阅读说明：本技术 感光性树脂组合物、感光性树脂片、中空结构的制造方法及电子部件 (Photosensitive resin composition, photosensitive resin sheet, method for producing hollow structure, and electronic component ) 是由 桂田悠基 河野友孝 金森大典 于 2020-03-18 设计创作，主要内容包括：本发明的感光性树脂组合物为含有碱溶性聚酰亚胺(a)、含有不饱和键的化合物(b)、热交联性化合物(c)、具有下述通式(1)所示的结构并且具有光漂白性的光聚合引发剂(d-1)、和具有下述通式(1)所示的结构并且波长405nm下的摩尔吸光系数为1000L/(mol·cm)以上的光聚合引发剂(d-2)的感光性树脂组合物。(在通式(1)中,R～(1)表示卤原子、羟基、羧基、硝基、氰基、-NR～(3)R～(4)、碳原子数1～20的1价烃基、碳原子数1～20的酰基或碳原子数1～20的烷氧基,R～(3)和R～(4)各自独立地表示氢原子或碳原子数1～10的烷基。其中,烃基、酰基和烷氧基的氢原子的至少一部分可以被卤原子、羟基、羧基、硝基、氰基或-NR～(3)R～(4)取代,烃基中、酰基中和烷氧基中的烃基可以被醚键、硫醚键、酯键、硫酯键、酰胺键或氨基甲酸酯键中断。R～(2)表示碳原子数1～5的烷基。式中的＊是指在＊部分与相邻的基团结合。)进一步,本发明的感光性树脂组合物为含有碱溶性聚酰亚胺(a)、含有不饱和键的化合物(b)、热交联性化合物(c)、2种以上肟酯系光聚合引发剂(d)的感光性树脂组合物。本发明的感光性树脂组合物可以将中空结构体的盖部分高灵敏度并且良好地通过光刻进行图案形成。使用了本发明的感光性树脂组合物的感光性树脂片在具有中空结构体的电子部件的中空结构体的盖用途中是有用的。(The photosensitive resin composition of the present invention comprises an alkali-soluble polyimide (a), a compound (b) having an unsaturated bond, a thermally crosslinkable compound (c), a photo-polymerization initiator (d-1) having a structure represented by the following general formula (1) and having photobleaching properties, and a photo-polymerization initiator (d-2) having a structure represented by the following general formula (1) and having a molar absorption coefficient at a wavelength of 405nm of 1000L/(mol cm) or more. (in the general formula (1), R 1 Represents a halogen atom, a hydroxyl group, a carboxyl group, a nitro group, a cyano group, -NR 3 R 4 A C1-valent hydrocarbon group of 1 to 20, a C1-20 acyl group or a C1-20 alkoxy group, R 3 And R 4 Each independently represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms. Wherein at least a part of the hydrogen atoms of the hydrocarbon group, the acyl group and the alkoxy group may be substituted by a halogen atom, a hydroxyl group, a carboxyl group, a nitro group, a cyano group or-NR 3 R 4 The hydrocarbyl group, the acyl group and the alkoxy group may be interrupted by an ether bond, a thioether bond, an ester bond, a thioester bond, an amide bond or a urethane bond. R 2 Represents an alkyl group having 1 to 5 carbon atoms. Wherein means that the bond between the onium moiety and the adjacent group is present. ) Further, the photosensitive resin composition of the present invention is a photosensitive resin composition containing (a) an alkali-soluble polyimide, (b) a compound having an unsaturated bond, (c) a thermally crosslinkable compound, and (d) at least 2 oxime ester photopolymerization initiators. The photosensitive resin composition of the present invention can pattern the lid portion of the hollow structure with high sensitivity and in a satisfactory manner by photolithography. The photosensitive resin sheet using the photosensitive resin composition of the present invention is useful for a hollow structure cover of an electronic component having a hollow structure.)

1. A photosensitive resin composition comprising an alkali-soluble polyimide (a), a compound (b) having an unsaturated bond, a thermally crosslinkable compound (c), a photo-polymerization initiator (d-1) having a structure represented by the following general formula (1) and having photobleachability, and a photo-polymerization initiator (d-2) having a structure represented by the following general formula (1) and having a molar absorption coefficient at a wavelength of 405nm of 1000L/(mol cm) or more,

in the general formula (1), R¹Represents a halogen atom, a hydroxyl group, a carboxyl group, a nitro group, a cyano group, -NR³R⁴A C1-valent hydrocarbon group of 1 to 20, a C1-20 acyl group or a C1-20 alkoxy group, R³And R⁴Each independently represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms; wherein at least a part of the hydrogen atoms of the hydrocarbon group, the acyl group and the alkoxy group may be substituted by a halogen atom, a hydroxyl group, a carboxyl group, a nitro group, a cyano group or-NR³R⁴Substituted, the hydrocarbyl group in the hydrocarbyl group, the acyl group and the alkoxy group may be interrupted by ether, thioether, ester, thioester, amide or carbamate linkages; r²Represents an alkyl group having 1 to 5 carbon atoms; wherein means that the bond between the onium moiety and the adjacent group is present.

2. A photosensitive resin composition comprising an alkali-soluble polyimide (a), a compound (b) having an unsaturated bond, a thermally crosslinkable compound (c), and 2 or more oxime ester photopolymerization initiators (d).

3. The photosensitive resin composition according to claim 2, wherein the oxime ester type photopolymerization initiator (d) contains at least 1 or more types of photopolymerization initiator (d-1) having a structure represented by the following general formula (2) and having photobleachability,

in the general formula (2), R¹Represents a halogen atom, a hydroxyl group, a carboxyl group, a nitro group, a cyano group, -NR³R⁴A C1-valent hydrocarbon group of 1 to 20, a C1-20 acyl group or a C1-20 alkoxy group, R³And R⁴Each independently represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms; wherein at least a part of the hydrogen atoms of the hydrocarbon group, the acyl group and the alkoxy group may be substituted by a halogen atom, a hydroxyl group, a carboxyl group, a nitro group, a cyano group or-NR³R⁴(ii) substituted, the hydrocarbyl group in the hydrocarbyl group, in the acyl group and in the alkoxy group may be interrupted by an ether, thioether, ester, thioester, amide or carbamate linkage; r²Represents an alkyl group having 1 to 5 carbon atoms; wherein means that the bond between the onium moiety and the adjacent group is present.

4. The photosensitive resin composition according to claim 2 or 3, wherein the oxime ester type photopolymerization initiator (d) comprises at least 1 or more photopolymerization initiators (d-2) having a structure represented by the following general formula (3) and having a molar absorption coefficient at a wavelength of 405nm of 1000L/(mol-cm) or more,

in the general formula (3), R¹Represents a halogen atom, a hydroxyl group, a carboxyl group, a nitro group, a cyano group, -NR³R⁴A C1-valent hydrocarbon group of 1 to 20, a C1-20 acyl group or a C1-20 alkoxy group, R³And R⁴Each independently represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms; wherein said hydrocarbyl group, said acyl groupThe group and at least a part of the hydrogen atoms of the alkoxy group may be substituted by a halogen atom, a hydroxyl group, a carboxyl group, a nitro group, a cyano group or-NR³R⁴(ii) substituted, the hydrocarbyl group in the hydrocarbyl group, in the acyl group and in the alkoxy group may be interrupted by an ether, thioether, ester, thioester, amide or carbamate linkage; r²Represents an alkyl group having 1 to 5 carbon atoms; wherein means that the bond between the onium moiety and the adjacent group is present.

5. The photosensitive resin composition according to any one of claims 1 and 3 to 4, wherein the photopolymerization initiator (d-1) is represented by the following general formula (4),

in the general formula (4), R⁵～R⁷Each independently represents a halogen atom, a hydroxyl group, a carboxyl group, a nitro group, a cyano group, -NR⁹R¹⁰A C1-valent hydrocarbon group of 1 to 20, a C1-20 acyl group or a C1-20 alkoxy group, R⁹And R¹⁰Each independently represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms; wherein at least a part of the hydrogen atoms of the hydrocarbon group, the acyl group and the alkoxy group may be substituted by a halogen atom, a hydroxyl group, a carboxyl group, a nitro group, a cyano group or-NR⁹R¹⁰(ii) substituted, the hydrocarbyl group in the hydrocarbyl group, in the acyl group and in the alkoxy group may be interrupted by an ether, thioether, ester, thioester, amide or carbamate linkage; r⁸Represents an alkyl group having 1 to 5 carbon atoms; a represents an integer of 0 to 5, b represents an integer of 0 to 4; a represents CO or a direct bond.

6. The photosensitive resin composition according to any one of claims 1 and 4 to 5, wherein the photopolymerization initiator (d-2) is represented by the following general formula (5),

in the general formula (5), R¹¹～R¹³Each independently represents a halogen atom, a hydroxyl group, a carboxyl group, a nitro group, a cyano group, -NR¹⁵R¹⁶A C1-valent hydrocarbon group of 1 to 20, a C1-20 acyl group or a C1-20 alkoxy group, R¹⁵And R¹⁶Each independently represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms; wherein at least a part of the hydrogen atoms of the hydrocarbon group, the acyl group and the alkoxy group may be substituted by a halogen atom, a hydroxyl group, a carboxyl group, a nitro group, a cyano group or-NR¹⁵R¹⁶(ii) substituted, the hydrocarbyl group in the hydrocarbyl group, in the acyl group and in the alkoxy group may be interrupted by an ether, thioether, ester, thioester, amide or carbamate linkage; r¹⁴Represents an alkyl group having 1 to 5 carbon atoms; e represents an integer of 0 to 4, and f represents an integer of 0 to 3; b represents CO or a direct bond; d represents-N (R)¹⁷) -or-C (R)¹⁸)(R¹⁹)-；R¹⁷～R¹⁹Each independently represents a hydrogen atom or a 1-valent hydrocarbon substituent having 1 to 10 carbon atoms.

7. The photosensitive resin composition according to any one of claims 1 and 4 to 6, wherein the content of the photopolymerization initiator (d-2) is 5 to 50 parts by mass based on 100 parts by mass of the total solid content of the photopolymerization initiator (d-1).

8. The photosensitive resin composition according to any one of claims 1 to 7, wherein the alkali-soluble polyimide (a) has a phenolic hydroxyl group or a carboxyl group.

9. The photosensitive resin composition according to any one of claims 1 to 8, wherein the unsaturated bond-containing compound (b) has an isocyanate group or a blocked isocyanate group.

10. The photosensitive resin composition according to any one of claims 1 to 9, further comprising a sensitizer (e).

11. The photosensitive resin composition according to any one of claims 1 to 10, further comprising a filler (f).

12. The photosensitive resin composition according to claim 11, wherein the filler (f) is glass or a filler having an average particle diameter of 10 to 100 nm.

13. The photosensitive resin composition according to any one of claims 1 to 12, wherein a cured product of the photosensitive resin composition has an elastic modulus of 3GPa or more at 180 ℃.

14. The photosensitive resin composition according to any one of claims 1 to 13, wherein the thickness of the photosensitive resin after coating and drying on the substrate is 12 to 150 μm.

15. A photosensitive resin sheet comprising a support and a photosensitive resin layer formed on the support by using the photosensitive resin composition according to any one of claims 1 to 14.

16. The photosensitive resin sheet according to claim 15, wherein the support has a haze of 1% or less at a wavelength of 405 nm.

17. The photosensitive resin sheet according to claim 15 or 16, wherein the thickness of the support is 30 μm or less.

18. A hollow structure formed by a convex portion provided on a substrate of an electronic component and a cover, wherein the cover is formed of the photosensitive resin composition layer of the photosensitive resin sheet according to any one of claims 15 to 17.

19. An electronic component having the hollow structure of claim 18.

20. The electronic component of claim 19, which is an elastic wave filter.

21. A method for manufacturing a hollow structure, comprising the steps of: a laminating step (A) of laminating the photosensitive resin sheet according to any one of claims 15 to 17 on a projection provided for forming a hollow structure on a substrate so as to form a cover of the hollow structure, thereby forming a photosensitive resin layer; an exposure step (B) of irradiating a predetermined portion of the photosensitive resin layer with active light to photocure the exposed portion; a baking step (C) for heating the photosensitive resin layer to accelerate curing of the exposed portion; a peeling step (D) of peeling off the support; a developing step (E) for removing the photosensitive resin layer except for the exposed portion by using a developer; and a thermosetting step (F) of thermally curing the exposed portion of the photosensitive resin layer to form a cured resin product.

22. The method of manufacturing a hollow structure according to claim 21, wherein in the exposure step (B), the support is exposed without peeling the support from the photosensitive resin sheet.

23. A method for producing a hollow structure according to claim 21 or 22, wherein the baking temperature in the baking step (C) is 60 to 180 ℃.

Technical Field

The invention relates to a photosensitive resin composition, a photosensitive resin sheet, a method for manufacturing a hollow structure, and an electronic component.

Background

In recent years, with the miniaturization of devices such as mobile phones and smart phones, electronic components mounted thereon have been miniaturized and made lower in height. As electronic components requiring a hollow structure, for example, elastic wave filters and MEMS (Micro Electro Mechanical Systems) are known. Electronic components requiring a hollow structure have conventionally been generally formed using inorganic materials such as piezoelectric substrates, glass, and silicon. However, a method of using a photosensitive resin which is more easily miniaturized and has a lower height for a cap of a hollow structure is becoming mainstream. The photosensitive resin used as the cover is a sheet-shaped material (photosensitive resin sheet), and is generally a 3-layer structure in which the photosensitive resin layer is sandwiched between a support film and a protective film. When the photosensitive resin to be used as the cap is used, the protective film is peeled off, and the photosensitive resin layer is attached to a position where a hollow structure is to be formed, and then photolithography processing is performed, whereby the cap made of the photosensitive resin can be formed. The photosensitive resin is suitable for lowering the height of the photosensitive resin because it can be processed thinner than inorganic materials such as glass and silicon. Further, since the photosensitive resin can also be subjected to fine through hole processing for electrode formation, it is also suitable for miniaturization, and the method of using the photosensitive resin for the cover of the hollow structure has been in practical use.

Heretofore, as a photosensitive resin sheet used for a cover of a hollow structure, a photosensitive polyimide sheet containing a polyimide resin having excellent heat resistance, electrical characteristics, and mechanical characteristics has been proposed (for example, see patent document 1). However, polyimide resin has a problem that the pattern shape is likely to be inverted due to large absorption of light, and thus embedding of metal serving as a conductor is insufficient, and conduction failure is likely to occur.

Therefore, a photosensitive polyimide sheet having an alkali-soluble polyimide, a compound having an unsaturated bond, a thermally crosslinkable compound, and a specific photopolymerization initiator has been proposed (for example, see patent document 2). Even when a polyimide resin is used, the pattern can be rectangular or tapered, and a cover of a hollow structure made of a polyimide resin having excellent heat resistance, electrical characteristics, and mechanical characteristics can be formed in a good shape.

However, when the photosensitive resin sheet described in patent document 2 is processed, a high exposure amount is required for sufficient photocuring, and there is a problem that processing takes time. If the exposure amount is insufficient, there are problems such as the occurrence of cracks in the resin, the occurrence of a cap serving as a hollow structure of the resin, and the occurrence of surface roughness of the resin.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2010-10812

Patent document 2: international publication No. 2018/173840

Disclosure of Invention

Problems to be solved by the invention

The purpose of the present invention is to provide a photosensitive resin composition which can pattern the lid portion of a hollow structure with high sensitivity and good photolithography.

Means for solving the problems

In order to solve the above problems and achieve the object, the photosensitive resin composition of the present invention has the following configuration.

A photosensitive resin composition comprising an alkali-soluble polyimide (a), a compound (b) having an unsaturated bond, a thermally crosslinkable compound (c), a photopolymerization initiator (d-1) having a structure represented by the following general formula (1) and having photobleachability, and a photopolymerization initiator (d-2) having a structure represented by the following general formula (1) and having a molar absorption coefficient at a wavelength of 405nm of 1000L/(mol cm) or more.

(in the general formula (1), R¹Represents a halogen atom, a hydroxyl group, a carboxyl group, a nitro group, a cyano group, -NR³R⁴And a valence of 1 to 20 carbon atomsA hydrocarbon group, an acyl group having 1 to 20 carbon atoms or an alkoxy group having 1 to 20 carbon atoms, R³And R⁴Each independently represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms. Wherein at least a part of the hydrogen atoms of the hydrocarbon group, the acyl group and the alkoxy group may be substituted by a halogen atom, a hydroxyl group, a carboxyl group, a nitro group, a cyano group or-NR³R⁴The hydrocarbon group in the hydrocarbon group, the acyl group and the alkoxy group may be interrupted by an ether bond, a thioether bond, an ester bond, a thioester bond, an amide bond or a urethane bond. R²Represents an alkyl group having 1 to 5 carbon atoms. Wherein means that the bond between the onium moiety and the adjacent group is present. )

Further, the photosensitive resin composition of the present invention is a photosensitive resin composition containing (a) an alkali-soluble polyimide, (b) a compound having an unsaturated bond, (c) a thermally crosslinkable compound, and (d) at least 2 oxime ester photopolymerization initiators.

The photosensitive resin sheet of the present invention includes a support and a photosensitive resin layer formed on the support by using the photosensitive resin composition of the present invention.

Further, the method for manufacturing a hollow structure of the present invention includes the steps of: a laminating step (a) of laminating the photosensitive resin sheet described above on a projection provided for forming a hollow structure on a substrate so as to form a cover of the hollow structure and form a photosensitive resin layer; an exposure step (B) of irradiating a predetermined portion of the photosensitive resin layer with active light to photocure the exposed portion; a baking step (C) for heating the photosensitive resin layer to accelerate curing of the exposed portion; a peeling step (D) of peeling off the support; a developing step (E) for removing the photosensitive resin layer except for the exposed portion by using a developer; and a thermosetting step (F) of thermally curing the exposed portion of the photosensitive resin layer to form a cured resin product.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, the lid portion of the hollow structure can be patterned by photolithography with high sensitivity and in a satisfactory manner.

Drawings

Fig. 1 is a diagram showing one suitable processing method of an elastic wave filter (SAW filter) as one of the electronic components of the present invention and a photosensitive resin sheet of the present invention.

Fig. 2 is a schematic view showing a crack in the photosensitive resin layer.

Fig. 3 is a schematic view showing the bending of the cover formed of the photosensitive resin layer.

Fig. 4 is a schematic view showing a convex pattern in examples and comparative examples.

Fig. 5 is a schematic view showing the patterns of the caps made of the photosensitive resin layers in the examples and comparative examples.

Fig. 6 is a schematic view of a wafer on which a projection pattern was formed in examples and comparative examples.

Detailed Description

Hereinafter, preferred embodiments of the photosensitive resin composition, the photosensitive resin sheet, the method for producing a hollow structure, and the electronic component of the present invention will be described in detail. However, the present invention is not limited to the following embodiments, and can be carried out by being variously modified depending on the purpose and the application.

< photosensitive resin composition >

(alkali-soluble polyimide)

The photosensitive resin composition of the present invention contains an alkali-soluble polyimide (a). The alkali-soluble polyimide (a) is a ring-closed polyimide having a solubility in a 2.38 mass% aqueous tetramethylammonium solution of 0.1g/100g or more at a temperature of 23 ℃.

The alkali-soluble polyimide (a) preferably has at least one of a carboxyl group, a phenolic hydroxyl group, a sulfonic acid group and a thiol group at the end of the main chain. This is because the alkali solubility of the alkali-soluble polyimide (a) can be improved by this constitution. In view of the utility to alkali developing solutions generally used in the semiconductor industry, the alkali-soluble polyimide (a) preferably has a phenolic hydroxyl group or a carboxyl group at the end of the main chain, and particularly preferably has a phenolic hydroxyl group. The introduction of a carboxyl group, a phenolic hydroxyl group, a sulfonic acid group, or a thiol group into the main chain end can be performed by using a blocking agent having these groups. By capping the main chain end, the number of repeating units of the alkali-soluble polyimide (a) is appropriately reduced. Therefore, the processability of a fine pattern of the photosensitive resin composition containing the alkali-soluble polyimide (a) can be improved.

The alkali-soluble polyimide (a) having at least one group selected from a carboxyl group, a phenolic hydroxyl group, a sulfonic acid group and a thiol group at the end of the main chain is preferably, for example, a polyimide having a structure represented by the following general formula (6) or the following general formula (7).

In the general formulae (6) and (7), X represents a 1-valent organic group having at least one group selected from a carboxyl group, a phenolic hydroxyl group, a sulfonic acid group and a thiol group. Y represents a 2-valent organic group having at least one group selected from a carboxyl group, a phenolic hydroxyl group, a sulfonic acid group and a thiol group. X and Y preferably have a phenolic hydroxyl group or a carboxyl group, and particularly preferably have a phenolic hydroxyl group.

Furthermore, R²⁰Represents a 4-14 valent organic group, R²¹Represents a 2-12 valent organic group. R²²And R²³Each independently represents a carboxyl group, a phenolic hydroxyl group, a sulfonic acid group or a thiol group. R²²And R²³The phenolic hydroxyl group or carboxyl group is preferable, and the phenolic hydroxyl group is particularly preferable.

Further, α and β each independently represent an integer in the range of 0 to 10. Of these α and β, α + β is preferably 1 or more. n represents the number of repetitions of the structural unit of the polymer. The range of n is 3 to 200. When n is 3 or more, the coating property of the photosensitive resin composition can be improved. From the viewpoint of improving the coatability, n is preferably 5 or more. On the other hand, if n is 200 or less, the solubility of the alkali-soluble polyimide (a) in the alkali developing solution can be improved. From the viewpoint of improving the solubility, n is preferably 100 or less. In addition, in each polymer chain, n is an integer, but n obtained by analysis from the alkali-soluble polyimide (a) may not be an integer.

In the above general formulae (6) and (7), R²⁰Is a 4-14 valent organic group having a structure derived from a tetracarboxylic dianhydride. Such R²⁰Preferably an organic group having 5 to 40 carbon atoms and containing an aromatic group or a cyclic aliphatic group.

Examples of the tetracarboxylic dianhydride include aromatic tetracarboxylic dianhydride, aliphatic tetracarboxylic dianhydride, and the like. Examples of the aromatic tetracarboxylic acid dianhydride include pyromellitic dianhydride, 3,3 ', 4, 4' -biphenyltetracarboxylic acid dianhydride, 2,3,3 ', 4' -biphenyltetracarboxylic acid dianhydride, 2 ', 3, 3' -biphenyltetracarboxylic acid dianhydride, 3,3 ', 4, 4' -benzophenonetetracarboxylic acid dianhydride, 2 ', 3, 3' -benzophenonetetracarboxylic acid dianhydride, 2-bis (3, 4-dicarboxyphenyl) propane dianhydride, 2-bis (2, 3-dicarboxyphenyl) propane dianhydride, 1-bis (3, 4-dicarboxyphenyl) ethane dianhydride, 1-bis (2, 3-dicarboxyphenyl) ethane dianhydride, bis (3, 4-dicarboxyphenyl) methane dianhydride, bis (2, 3-dicarboxyphenyl) methane dianhydride, Bis (3, 4-dicarboxyphenyl) sulfone dianhydride, bis (3, 4-dicarboxyphenyl) ether dianhydride, 1,2,5, 6-naphthalene tetracarboxylic dianhydride, 9-bis (3, 4-dicarboxyphenyl) fluorenic dianhydride, 9-bis {4- (3, 4-dicarboxyphenoxy) phenyl } fluorenic dianhydride, 2,3,6, 7-naphthalene tetracarboxylic dianhydride, 2,3,5, 6-pyridine tetracarboxylic dianhydride, 3,4,9, 10-perylene tetracarboxylic dianhydride, 2-bis (3, 4-dicarboxyphenyl) hexafluoropropane dianhydride, and the like. Examples of the aliphatic tetracarboxylic acid dianhydride include butane tetracarboxylic acid dianhydride, 1,2,3, 4-cyclopentane tetracarboxylic acid dianhydride, and the like.

Examples of the tetracarboxylic dianhydride include acid dianhydrides having the following structures. In the present embodiment, as the tetracarboxylic dianhydride, 2 or more kinds among the above-described aromatic tetracarboxylic dianhydride, aliphatic tetracarboxylic dianhydride, and acid dianhydride having the structure shown below can be used.

In the acid having the structureIn the general formula of the dianhydride, R²⁴Represents an oxygen atom, C (CF)₃)₂、C(CH₃)₂Or SO₂。R²⁵And R²⁶Each independently represents a hydroxyl group or a carboxyl group.

In the above general formulae (6) and (7), R²¹Is a 2-12 valent organic group having a structure derived from a diamine. Such R²¹Preferably an organic group having 5 to 40 carbon atoms and containing an aromatic group or a cyclic aliphatic group.

Examples of the diamine include a hydroxyl group-containing diamine, a carboxyl group-containing diamine, a thiol group-containing diamine, an aromatic diamine, a compound obtained by substituting at least a part of hydrogen atoms of an aromatic ring thereof with an alkyl group or a halogen atom, and an aliphatic diamine.

Examples of the hydroxyl group-containing diamine include bis- (3-amino-4-hydroxyphenyl) hexafluoropropane, bis (3-amino-4-hydroxyphenyl) sulfone, bis (3-amino-4-hydroxyphenyl) propane, bis (3-amino-4-hydroxyphenyl) methane, bis (3-amino-4-hydroxyphenyl) ether, bis (3-amino-4-hydroxy) biphenyl, and bis (3-amino-4-hydroxyphenyl) fluorene. Examples of the diamine having a carboxyl group include 2, 2-bis [ 3-amino-4-carboxyphenyl ] propane, 2, 2-bis [ 4-amino-3-carboxyphenyl ] propane, 2, 2-bis [ 3-amino-4-carboxyphenyl ] hexafluoropropane, 4 '-diamino-2, 2', 5,5 '-tetracarboxyldiphenylmethane, 3' -diamino-4, 4 '-dicarboxyldiphenyl ether, 4' -diamino-3, 3 '-dicarboxyldiphenyl ether, 4' -diamino-2, 2 ', 5, 5' -tetracarboxyldiphenyl ether, 3,3 ' -diamino-4, 4 ' -dicarboxydiphenylsulfone, 4 ' -diamino-3, 3 ' -dicarboxydiphenylsulfone, 4 ' -diamino-2, 2 ', 5,5 ' -tetracarboxydiphenylsulfone, 2-bis [4- (4-amino-3-carboxyphenoxy) phenyl ] propane, 2-bis [4- (4-amino-3-carboxyphenoxy) phenyl ] sulfone and the like. Examples of the diamine containing a thiol group include dimercaptophenylenediamine and the like.

Examples of the aromatic diamine include 3,3 ' -diaminodiphenyl ether, 3,4 ' -diaminodiphenyl ether, 4 ' -diaminodiphenyl ether, 3,3 ' -diaminodiphenyl methane, 3,4 ' -diaminodiphenyl methane, 4 ' -diaminodiphenyl methane, 3,3 ' -diaminodiphenyl sulfone, 3,4 ' -diaminodiphenyl sulfone, 4 ' -diaminodiphenyl sulfone, 3,4 ' -diaminodiphenyl sulfide, 4 ' -diaminodiphenyl sulfide, 1, 4-bis (4-aminophenoxy) benzene, 1, 3-bis (3-aminophenoxy) benzene, benzidine, m-phenylenediamine, p-phenylenediamine, and the like, 1, 5-naphthalenediamine, 2, 6-naphthalenediamine, bis (4-aminophenoxyphenyl) sulfone, bis (3-aminophenoxyphenyl) sulfone, bis (4-aminophenoxy) biphenyl, bis {4- (4-aminophenoxy) phenyl } ether, 1, 4-bis (4-aminophenoxy) benzene, 2 ' -dimethyl-4, 4 ' -diaminobiphenyl, 2 ' -diethyl-4, 4 ' -diaminobiphenyl, 3,3 ' -dimethyl-4, 4 ' -diaminobiphenyl, 3,3 ' -diethyl-4, 4 ' -diaminobiphenyl, 2 ', 3,3 ' -tetramethyl-4, 4 ' -diaminobiphenyl, 3,3 ', 4,4 ' -tetramethyl-4, 4 ' -diaminobiphenyl, 2 ' -bis (trifluoromethyl) -4,4 ' -diaminobiphenyl, 9-bis (4-aminophenyl) fluorene, and the like. Examples of the aliphatic diamine include cyclohexanediamine and methylenebiscyclohexylamine.

Examples of the diamine include those having the following structures. In the present embodiment, as the diamine, 2 or more of the above-described hydroxyl group-containing diamines, carboxyl group-containing diamines, thiol group-containing diamines, aromatic diamines, compounds obtained by substituting at least a part of hydrogen atoms in the aromatic ring thereof with an alkyl group or a halogen atom, aliphatic diamines, and diamines having the structure shown below can be used.

In the general formula of the diamine having the above structure, R²⁴Represents an oxygen atom, C (CF)₃)₂、C(CH₃)₂Or SO₂。R²⁵～R²⁸Each independently represents a hydroxyl group or a carboxyl group.

Among the above diamines, bis- (3-amino-4-hydroxyphenyl) hexafluoropropane, bis (3-amino-4-hydroxyphenyl) sulfone, bis (3-amino-4-hydroxyphenyl) propane, bis (3-amino-4-hydroxyphenyl) methane, bis (3-amino-4-hydroxyphenyl) ether, bis (3-amino-4-hydroxy) biphenyl, bis (3-amino-4-hydroxyphenyl) fluorene, 2-bis [ 3-amino-4-carboxyphenyl ] propane, 2-bis [ 4-amino-3-carboxyphenyl ] propane, 2-bis [ 3-amino-4-carboxyphenyl ] hexafluoropropane, bis (3-amino-4-carboxyphenyl) hexafluoropropane, bis (3-amino-4-hydroxyphenyl) sulfone, bis (3-amino-4-hydroxyphenyl) methane, bis (3-amino-4-hydroxyphenyl) ether, 4,4 ' -diamino-2, 2 ', 5,5 ' -tetracarboxyldiphenylmethane, 3 ' -diamino-4, 4 ' -dicarboxydiphenyl ether, 4 ' -diamino-3, 3 ' -dicarboxydiphenyl ether, 4 ' -diamino-2, 2 ', 5,5 ' -tetracarboxydiphenyl ether, 3 ' -diamino-4, 4 ' -dicarboxydiphenyl sulfone, 4 ' -diamino-3, 3 ' -dicarboxydiphenyl sulfone, 4 ' -diamino-2, 2 ', 5,5 ' -tetracarboxydiphenyl sulfone, 2, 2-bis [4- (4-amino-3-carboxyphenoxy) phenyl ] propane, 2-bis [4- (4-amino-3-carboxyphenoxy) phenyl ] sulfone, 3 ' -diaminodiphenyl ether, 3,4 ' -diaminodiphenyl ether, 4 ' -diaminodiphenyl ether, 3 ' -diaminodiphenylmethane, 3,4 ' -diaminodiphenylmethane, 4 ' -diaminodiphenylmethane, 3 ' -diaminodiphenyl sulfone, 3,4 ' -diaminodiphenyl sulfone, 4 ' -diaminodiphenyl sulfone, 3,4 ' -diaminodiphenyl sulfide, 4 ' -diaminodiphenyl sulfide, m-phenylenediamine, p-phenylenediamine, 1, 4-bis (4-aminophenoxy) benzene, 9-bis (4-aminophenyl) fluorene, and a diamine having the structure shown below.

In the above general formulae (6) and (7), R²²And R²³As described above, each independently represents a carboxyl group, a phenolic hydroxyl group, a sulfonic acid group, or a thiol group. By adjusting these R²²And R²³The amount of the alkali-soluble group (b) in the alkali aqueous solution is not particularly limited, and the alkali-soluble polyimide (a) may be used alone or in combination with other additives.

Further, in the alkali-soluble polyimide (a) having a structure represented by the general formulae (6) and (7), the aliphatic compound having a siloxane structure and R may be added within a range in which heat resistance is not lowered²¹And (3) copolymerization. By copolymerizing an aliphatic compound having a siloxane structure, the transparency of the alkali-soluble polyimide (a) can be improved, the adhesion between the alkali-soluble polyimide (a) and a substrate can be improved, and lamination can be easily performed when the alkali-soluble polyimide (a) is used for a photosensitive resin sheet. Examples of the aliphatic compound having a siloxane structure include 1, 3-bis (3-aminopropyl) tetramethyldisiloxane and 1, 3-bis (p-amino-phenyl) octamethylpentasiloxane in the case of a diamine. It is preferable that they are copolymerized in an amount of 1 to 10 mol% based on the total diamine of the alkali-soluble polyimide (a).

Further, in the general formula (6), X is derived from a primary monoamine as an end-capping agent. Preferred primary monoamines as the blocking agent are, for example, 5-amino-8-hydroxyquinoline, 1-hydroxy-7-aminonaphthalene, 1-hydroxy-6-aminonaphthalene, 1-hydroxy-5-aminonaphthalene, 1-hydroxy-4-aminonaphthalene, 2-hydroxy-7-aminonaphthalene, 2-hydroxy-6-aminonaphthalene, 2-hydroxy-5-aminonaphthalene, 1-carboxy-7-aminonaphthalene, 1-carboxy-6-aminonaphthalene, 1-carboxy-5-aminonaphthalene, 2-carboxy-7-aminonaphthalene, 2-carboxy-6-aminonaphthalene, 2-carboxy-5-aminonaphthalene, 2-hydroxy-7-aminonaphthalene, 1-hydroxy-5-aminonaphthalene, 1-hydroxy-4-aminonaphthalene, 2-hydroxy-7-aminonaphthalene, 2-carboxy-6-aminonaphthalene, 2-carboxy-5-aminonaphthalene, and, 2-aminobenzoic acid, 3-aminobenzoic acid, 4-aminosalicylic acid, 5-aminosalicylic acid, 6-aminosalicylic acid, 2-aminobenzenesulfonic acid, 3-aminobenzenesulfonic acid, 4-aminobenzenesulfonic acid, 3-amino-4, 6-dihydroxypyrimidine, 2-aminophenol, 3-aminophenol, 4-aminophenol, 2-aminothiophenol, 3-aminothiophenol, 4-aminothiophenol and the like. As such a terminal-blocking material, 2 or more kinds of these primary amines can be used.

Further, in the general formula (7), Y is derived from a dicarboxylic anhydride as a terminal blocking agent. The dicarboxylic anhydride as the end-capping agent is preferably, for example, 4-carboxyphthalic anhydride, 3-hydroxyphthalic anhydride, cis-aconitic anhydride, or the like. As such a capping material, 2 or more of these dicarboxylic anhydrides can be used.

The alkali-soluble polyimide (a) in the present invention may contain an alkali-soluble polyimide other than the substances having the structures represented by the general formula (6) or the general formula (7). In this case, the alkali-soluble polyimide having a structure represented by general formula (6) or general formula (7) is preferably contained in an amount of 30 mass% or more, and more preferably 60 mass% or more, based on the mass of the entire alkali-soluble polyimide (a). By containing 30% by mass or more of the alkali-soluble polyimide represented by the general formula (6) or (7), shrinkage at the time of thermal curing of the alkali-soluble polyimide (a) can be suppressed. The kind of the alkali-soluble polyimide having a structure other than that represented by the general formula (6) or the general formula (7) and the content in the alkali-soluble polyimide (a) are preferably selected within a range that does not impair the heat resistance and solubility in an alkali developing solution of the alkali-soluble polyimide (a) obtained by the final heat treatment.

The alkali-soluble polyimide (a) can be synthesized by any method in which a part of diamine is replaced with a monoamine as an end-capping agent or a tetracarboxylic dianhydride is replaced with a dicarboxylic anhydride as an end-capping agent. For example, the alkali-soluble polyimide (a) can be synthesized by the method 1 of reacting a tetracarboxylic dianhydride with a diamine compound and a monoamine at a low temperature; a 2 nd method of reacting a tetracarboxylic dianhydride and a dicarboxylic anhydride with a diamine compound at low temperature; a polyimide precursor is obtained by a method of obtaining a diester from a tetracarboxylic dianhydride and an alcohol, and then reacting the diester with a diamine and a monoamine in the presence of a condensing agent, and then the obtained polyimide precursor is completely imidized by an arbitrary imidization reaction method, method 3.

In the present invention, the imidization ratio of the alkali-soluble polyimide (a) is preferably 90% or more from the viewpoint of further improving the electrical characteristics, mechanical characteristics, heat resistance, moisture resistance and residual film ratio of the polyimide. Examples of the method for adjusting the imidization ratio of the alkali-soluble polyimide (a) to the above range include a method in which the imidization reaction is carried out under a dry nitrogen gas flow at a reaction temperature of 160 ℃ or higher for a reaction time of 2 hours or longer.

Here, theThe imidization ratio of the alkali-soluble polyimide (a) in the present invention can be determined by the following method. First, the infrared absorption spectrum of the alkali-soluble polyimide (a) was measured to obtain 1377cm as an absorption peak derived from the imide structure^-1Near peak intensity P1. Next, the alkali-soluble polyimide (a) was heat-treated at 350 ℃ for 1 hour, and then the infrared absorption spectrum was measured again to obtain 1377cm^-1Near peak intensity P2. The imidization ratio of the alkali-soluble polyimide (a) can be determined based on the following formula using the obtained peak intensities P1 and P2.

Imidization rate [% ] is (peak intensity P1 ÷ peak intensity P2) × 100

The end-capping agent introduced into the alkali-soluble polyimide (a) can be detected by the following method. For example, an alkali-soluble polyimide (a) having an end-capping agent introduced therein is dissolved in an acidic solution and decomposed into an amine component and a carboxylic anhydride component, which are constituent units of the polyimide. Then, the amine component and the carboxylic anhydride component are analyzed by Gas Chromatography (GC) and NMR, whereby the end-capping agent of the alkali-soluble polyimide (a) can be detected. Further, the alkali-soluble polyimide (a) having the terminal-capping agent introduced thereinto was subjected to thermal cracking gas chromatography (PGC), infrared spectroscopy and¹³the end-capping agent of the alkali-soluble polyimide (a) can also be detected by analysis by CNMR spectroscopy.

(Compound having unsaturated bond)

The photosensitive resin composition of the present invention contains a compound (b) containing an unsaturated bond. The unsaturated bond-containing compound (b) is an unsaturated bond-containing compound. Examples of the unsaturated bond-containing group in the unsaturated bond-containing compound (b) include unsaturated double bond-containing groups such as a vinyl group, an allyl group, an acryloyl group, and a methacryloyl group, and unsaturated triple bond-containing groups such as a propargyl group. The unsaturated bond-containing compound (b) may contain 2 or more of these unsaturated bond-containing groups. Among them, conjugated vinyl groups, acryloyl groups, and methacryloyl groups are preferable in terms of polymerizability. In addition, the number of unsaturated bonds in the compound (b) containing an unsaturated bond is preferably 1 to 6 from the viewpoint of suppressing pattern cracks due to excessive crosslinking points caused by polymerization reaction.

The unsaturated bond-containing compound (b) preferably has an isocyanate group or a blocked isocyanate group, and particularly preferably has a blocked isocyanate group from the viewpoint of stability. The alkali-soluble polyimide (a) and the compound (b) having an unsaturated bond form a crosslinked structure by reacting an isocyanate group or a blocked isocyanate group with an acid group of the alkali-soluble polyimide (a). This increases the strength of the resin composition, and when the photosensitive resin sheet is formed as a hollow cap, the shape of the cap can be easily maintained.

Examples of the unsaturated bond-containing compound (b) having no isocyanate group or a blocked isocyanate group include diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, trimethylolpropane diacrylate, trimethylolpropane triacrylate, trimethylolpropane dimethacrylate, trimethylolpropane trimethacrylate, styrene, α -methylstyrene, 1, 2-dihydronaphthalene, 1, 3-diisopropenylbenzene, 3-methylstyrene, 4-methylstyrene, 2-vinylnaphthalene, butyl acrylate, butyl methacrylate, isobutyl acrylate, hexyl acrylate, isooctyl acrylate, isobornyl acrylate, and mixtures thereof, Isobornyl methacrylate, cyclohexyl methacrylate, 1, 3-butanediol diacrylate, 1, 3-butanediol dimethacrylate, neopentyl glycol diacrylate, 1, 4-butanediol dimethacrylate, 1, 6-hexanediol diacrylate, 1, 6-hexanediol dimethacrylate, 1, 9-nonanediol dimethacrylate, 1, 10-decanediol dimethacrylate, dimethylol-tricyclodecane diacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, pentaerythritol trimethacrylate, pentaerythritol tetramethacrylate, dipentaerythritol hexaacrylate, dipentaerythritol hexamethacrylate, 2-hydroxyethyl acrylate, poly (ethylene glycol) methacrylate, poly (ethylene glycol) acrylate), poly (ethylene glycol) acrylate, poly (ethylene glycol) acrylate), poly (ethylene glycol), and poly (ethylene glycol), and poly (ethylene glycol), and poly (ethylene glycol), and poly (ethylene glycol), and poly, 2-hydroxyethyl methacrylate, 1, 3-diacryloyloxy-2-hydroxypropane, 1, 3-dimethacryloxy-2-hydroxypropane, methylenebisacrylamide, N-dimethylacrylamide, N-methylolacrylamide, 2,6, 6-tetramethylpiperidine methacrylate, 2,6, 6-tetramethylpiperidine acrylate, N-methyl-2, 2,6, 6-tetramethylpiperidine methacrylate, N-methyl-2, 2,6, 6-tetramethylpiperidine acrylate, ethylene oxide-modified bisphenol A diacrylate, ethylene oxide-modified bisphenol A dimethacrylate, propylene oxide-modified bisphenol A diacrylate, propylene oxide-modified bisphenol A methacrylate, and mixtures thereof, Propoxylated ethoxylated bisphenol A diacrylate, propoxylated ethoxylated bisphenol A dimethacrylate, N-vinyl pyrrolidone, N-vinyl caprolactam, and the like. Examples of the unsaturated bond-containing compound (b) having an isocyanate group include 2-isocyanatoethyl acrylate, 2-isocyanatoethyl methacrylate, 1- (bisacryloxymethyl) ethyl isocyanate, and 2- (2-isocyanatoethoxy) ethyl methacrylate. Examples of the unsaturated bond-containing compound (b) having a blocked isocyanate group include 2- [ O- (1' -methylpropyleneamino) carboxyamino ] ethyl methacrylate and 2- [ (3, 5-dimethylpyrazolyl) carbonylamino ] ethyl methacrylate. The compound (b) having an unsaturated bond may contain 2 or more of them.

Among them, as the compound (b) having an unsaturated bond, 1, 9-nonanediol dimethacrylate, 1, 10-decanediol dimethacrylate, dimethylol-tricyclodecane diacrylate, isobornyl acrylate, isobornyl methacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, pentaerythritol trimethacrylate, pentaerythritol tetramethacrylate, dipentaerythritol hexaacrylate, dipentaerythritol hexamethacrylate, methylenebisacrylamide, N-dimethylacrylamide, N-methylolacrylamide, 2,6, 6-tetramethylpiperidine methacrylate, 2,6, 6-tetramethylpiperidine acrylate, N-methyl-2, 2,6, 6-tetramethylpiperidine, N-methyl-2, 2,6, 6-tetramethylpiperidine acrylate, ethylene oxide-modified bisphenol A diacrylate, ethylene oxide-modified bisphenol A dimethacrylate, propylene oxide-modified bisphenol A diacrylate, propylene oxide-modified bisphenol A methacrylate, propoxylated ethoxylated bisphenol A diacrylate, propoxylated ethoxylated bisphenol A dimethacrylate, N-vinylpyrrolidone, N-vinylcaprolactam, 2-isocyanatoethyl acrylate, 2-isocyanatoethyl methacrylate, 1- (bisacryloxymethyl) ethyl isocyanate, 2- (2-isocyanatoethoxy) ethyl methacrylate, 2- [ O- (1' -methylpropenylamino) carboxy-amino ] ethyl acrylate, poly (ethylene oxide-co-vinyl) acrylate, poly (propylene oxide-co-vinyl acetate), poly (propylene oxide-vinyl acetate), poly (ethylene oxide) -co-vinyl acetate, poly (ethylene oxide) -co-vinyl acetate, poly (ethylene oxide), 2- [ (3, 5-dimethylpyrazolyl) carbonylamino ] ethyl methacrylate. Among them, dipentaerythritol hexaacrylate, dipentaerythritol hexamethacrylate, ethylene oxide-modified bisphenol A diacrylate, ethylene oxide-modified bisphenol A dimethacrylate, propylene oxide-modified bisphenol A diacrylate, propylene oxide-modified bisphenol A methacrylate, 2-isocyanatoethyl acrylate, 2-isocyanatoethyl methacrylate, 1- (bisacryloxymethyl) ethyl isocyanate, 2- (2-isocyanatoethoxy) ethyl methacrylate, 2- [ O- (1' -methylpropyleneamino) carboxyamino ] ethyl methacrylate, and 2- [ (3, 5-dimethylpyrazolyl) carbonylamino ] ethyl methacrylate are more preferable.

The content of the unsaturated bond-containing compound (b) in the photosensitive resin composition of the present invention is preferably 40 parts by mass or more, and more preferably 50 parts by mass or more, per 100 parts by mass of the alkali-soluble polyimide (a), from the viewpoint of improving the residual film ratio after development. On the other hand, the content of the compound (b) containing an unsaturated bond is preferably 150 parts by mass or less, more preferably 100 parts by mass or less, per 100 parts by mass of the alkali-soluble polyimide (a), from the viewpoint of improving the heat resistance of the cured film.

The content of the unsaturated bond-containing compound (b) having an isocyanate group or a blocked isocyanate group in the photosensitive resin composition of the present invention is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, and still more preferably 20 parts by mass or more, per 100 parts by mass of the unsaturated bond-containing compound (b), from the viewpoint of easily maintaining the shape of the cap of the hollow structure. On the other hand, from the viewpoint of sufficiently exhibiting the alkali solubility of the alkali-soluble polyimide (a), the content of the unsaturated bond-containing compound (b) having an isocyanate group or a blocked isocyanate group is preferably 80 parts by mass or less, more preferably 50 parts by mass or less, and still more preferably 30 parts by mass or less, relative to 100 parts by mass of the unsaturated bond-containing compound (b).

(thermally crosslinkable Compound)

The photosensitive resin composition of the present invention contains a thermally crosslinkable compound (c). The thermally crosslinkable compound (c) is a compound having thermal crosslinking properties. The thermally crosslinkable compound (c) is preferably a compound containing at least 1 group of an alkoxymethyl group, a hydroxymethyl group and an epoxy group, and more preferably a compound having at least 2 groups of an alkoxymethyl group, a hydroxymethyl group and an epoxy group. The thermally crosslinkable compound (c) has at least 2 groups among these groups, and thus a crosslinked structure is formed by a reaction between the alkali-soluble polyimide (a) and the thermally crosslinkable compound (c) and a reaction between the thermally crosslinkable compounds (c). Therefore, the cured film obtained by heat-treating the thermally crosslinkable compound (c) can have improved mechanical properties and chemical resistance, and can easily maintain the shape of the hollow cap.

Examples of the compound having an alkoxymethyl group or hydroxymethyl group among the thermally crosslinkable compounds (c) include 46DMOC, 46DMOEP (trade name, manufactured by Asahi organic materials Co., Ltd.), DML-PC, DML-PEP, DML-OC, DML-OEP, DML-34X, DML-PTBP, DML-PCHP, DML-OCHP, DML-PFP, DML-PSBP, DML-POP, DML-MBOC, DML-MBPC, DML-MTrisPC, DML-BisOC-Z, DML-BisOCHP-Z, DML-BPC, DMLBisoc-P, DMOM-PC, DMOM-PTPC, TriDMOM-MBPC, TML-P, TriML-35XL, TML-HQ, TML-BP, TML-BPF, TML-BPE, TML-BPAF, TML-BPAP, TML-BPBP-TML-BPBP, TML-TMBPBP-35 XL, TML-HQ, TML-BPPP, TMOM-BPE, TMOM-BPA, TMOM-BPAF, TMOM-BPAP, HML-TPPHBA, HML-TPHAP, HMOM-TPPHBA, HMOM-TPHAP (trade name, manufactured by chemical industries, Ltd., Japan), "NIKALAC" (registered trademark) MX-290, "NIKALAC" MX-280, "NIKALAC" MX-270, "NIKALAC" MX-279, "NIKALAC" MW-100LM, "NIKALAC" MX-750LM (trade name, manufactured by Mitsu and ケミカル Co., Ltd.), and the like. The thermally crosslinkable compound (c) may contain 2 or more of them.

Examples of the compound having an epoxy group in the thermally crosslinkable compound (c) include bisphenol a type epoxy resins, bisphenol F type epoxy resins, propylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, polymethyl (glycidyloxypropyl), epoxy group-containing silicones, and the like. Specifically, examples thereof include "エピクロン" (registered trademark) 850-S, "エピクロン" HP-4032, "エピクロン" HP-7200, "エピクロン" HP-820, "エピクロン" HP-4700, "エピクロン" EXA-4710, "エピクロン" HP-4770, "エピクロン" EXA-859CRP, "エピクロン" EXA-1514, "エピクロン" EXA-4880, "エピクロン" EXA-4850- "150," エピクロン "EXA-4850-" 1000, "エピクロン" EXA-4816, "エピクロン" EXA-4822 (trade name, available from Dajapan インキ chemical industries), "リカレジン" (registered trademark) BEO-60E, "リカレジン" BPO-20E, "リカレジン" HBE-100, "リカレジン" DME-100 (trade name, manufactured by Nippon chemical Co., Ltd.), EP-4003S, EP-4000S (trade name, manufactured by ADEKA Co., Ltd.), PG-100, CG-500, EG-200 (trade name, manufactured by Osaka ガ ス ケミカル Co., Ltd.), NC-3000, NC-6000 (trade name, manufactured by Nippon Kagaku Co., Ltd.), "EPOX" (registered trademark) -MK R508, "EPOX" -MK R540, "EPOX" -MK R710, "EPOX" -MK R1710, VG3101L, VG3101M80 (trade name, manufactured by プリンテック Co., Ltd.), "セロキサイド" (registered trademark) 2021P, "セロキサイド" 2081, "セロキサイド" 2083, "セロキサイド" 2085 (trade name, manufactured by ダイセル chemical industries, Ltd.), and the like. The thermally crosslinkable compound (c) may contain 2 or more of them.

The content of the thermally crosslinkable compound (c) in the photosensitive resin composition of the present invention is preferably 1 part by mass or more, and more preferably 5 parts by mass or more, per 100 parts by mass of the alkali-soluble polyimide (a), from the viewpoint of improving the heat resistance of the cured film. On the other hand, the content of the thermally crosslinkable compound (c) is preferably 70 parts by mass or less, more preferably 50 parts by mass or less, per 100 parts by mass of the alkali-soluble polyimide (a), from the viewpoint of improving the residual film ratio after development.

(photopolymerization initiator)

The photosensitive resin composition of the present invention comprises an alkali-soluble polyimide (a), a compound (b) having an unsaturated bond, a thermal crosslinking agent (c), a photopolymerization initiator (d-1) and a photopolymerization initiator (d-2).

The photopolymerization initiator (d-1) is a photo-bleaching photopolymerization initiator. Photobleachability means a property of exhibiting discoloration by decomposition by exposure to light and reducing light absorption. Such a photopolymerization initiator can transmit light to the inside because transparency is improved by light irradiation.

The photopolymerization initiator (d-2) has a molar absorption coefficient of 1000L/(mol cm) or more at a wavelength of 405 nm. The molar absorption coefficient is a constant indicating the ability of the substance to absorb light, and a larger value indicates a higher ability to absorb light.

The photopolymerization initiator has a molar absorption coefficient ε at a wavelength of 405nm₄₀₅The measurement can be carried out by the following method. First, as in the evaluation of photobleachability, a photopolymerization initiator was dissolved in a soluble solvent, and the absorbance Abs at a wavelength of 405nm was measured by a spectrophotometer₄₀₅. Further, the molar absorption coefficient ε at a wavelength of 405nm can be calculated by substituting the value into the following Lambert beer formula₄₀₅。

ε₄₀₅＝Abs₄₀₅/(C·l)

C represents the concentration of the solution, and l represents the optical path length of the measurement sample.

The photopolymerization initiator (d-1) and the photopolymerization initiator (d-2) have a structure represented by the following general formula (1).

In the general formula (1), R¹Represents a halogen atom, a hydroxyl group, a carboxyl group, a nitro group, a cyano group, -NR³R⁴A C1-valent hydrocarbon group of 1 to 20, a C1-20 acyl group or a C1-20 alkoxy group, R³And R⁴Each independently represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms. Wherein at least a part of the hydrogen atoms of the hydrocarbon group, the acyl group and the alkoxy group may be substituted by a halogen atom, a hydroxyl group, a carboxyl group, a nitro group, a cyano group or-NR³R⁴The hydrocarbyl group, the acyl group and the alkoxy group may be interrupted by an ether bond, a thioether bond, an ester bond, a thioester bond, an amide bond or a urethane bond. R²Represents an alkyl group having 1 to 5 carbon atoms. Wherein means that the bond between the onium moiety and the adjacent group is present. R²Preferably methyl.

By containing the alkali-soluble polyimide (a), the compound (b) having an unsaturated bond, the photopolymerization initiator (d-1) and the photopolymerization initiator (d-2), a negative pattern which is easily soluble in an alkali developer before exposure but becomes insoluble in an alkali developer after exposure can be formed. The photopolymerization initiator (d-1) has photobleaching properties, and therefore the photosensitive resin composition of the present invention exhibits high internal curability, and when used as a cap for a hollow structure, the pattern shape can be easily formed into a rectangular shape or a forward tapered shape.

The photobleachability of the photopolymerization initiator can be investigated by the following method. First, a photopolymerization initiator was dissolved in a soluble solvent, and the absorbance was measured by a spectrophotometer. The concentration of the solution at this time was adjusted so as to fall within the measurement range of the spectrophotometer. As the solvent, methanol, ethanol, chloroform, acetonitrile, propylene glycol monomethyl ether acetate, ethyl lactate, and the like which do not inhibit the measurement of the absorbance of the photopolymerization initiator can be used. Next, the solution of the photopolymerization initiator was sufficiently exposed to light of a wavelength at which the photopolymerization initiator absorbs and reacts with light, and the absorbance was measured again. When the absorbance at the maximum absorption wavelength before exposure is taken as 100%, the absorbance Abs before exposure (before exposure) is determined so that the absorbance in the long wavelength region is 20% as compared with the maximum absorption wavelength. In the case where there are two or more maximum absorption wavelengths, the maximum absorption wavelength in the long wavelength region is used. Next, the absorbance Abs (after exposure) after exposure at the same wavelength as Abs (before exposure) is obtained, and Abs (before exposure) and Abs (after exposure) are compared. When Abs (before exposure) > Abs (after exposure), it is indicated as a photo-polymerization initiator having photobleaching property.

The photo-bleaching photopolymerization initiator (d-1) has a small molar absorption coefficient, and therefore, when used alone, the photosensitive resin composition has low sensitivity, and if processed into a hollow structure cap at a low exposure dose, there are problems such as cracks in the resin, falling-in of the hollow structure cap as a resin, and surface roughness of the resin.

The photopolymerization initiator (d-2) has a high molar absorptivity, so that it has high surface curability, can improve the sensitivity of the photosensitive resin composition, and can improve cracks in the resin, the entrapment of a cap as a hollow structure of the resin, the surface roughness of the resin, and the like during low exposure processing. The photopolymerization initiator (d-2) tends to exhibit no photobleachability and lacks internal curability, and thus the pattern shape tends to be inverted. As described above, the photosensitive resin composition of the present invention contains the photopolymerization initiator (d-1) and the photopolymerization initiator (d-2), and thus, the balance between surface curability and internal curability is improved, and the lid portion of the hollow structure can be patterned by photolithography with high sensitivity and in a satisfactory manner.

Further, the photosensitive resin composition of the present invention is a photosensitive resin composition containing (a) an alkali-soluble polyimide, (b) a compound having an unsaturated bond, (c) a thermally crosslinkable compound, and (d) at least 2 oxime ester photopolymerization initiators.

The photosensitive resin composition of the present invention is preferably a photosensitive resin composition in which the oxime ester photopolymerization initiator (d) contains at least 1 or more kinds of photopolymerization initiators (d-1) having a structure represented by the following general formula (2) and having photobleachability.

In the general formula (2), R¹Represents a halogen atom or a hydroxyl groupRadical, carboxyl, nitro, cyano, -NR³R⁴A C1-valent hydrocarbon group of 1 to 20, a C1-20 acyl group or a C1-20 alkoxy group, R³And R⁴Each independently represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms. Wherein at least a part of the hydrogen atoms of the hydrocarbon group, the acyl group and the alkoxy group may be substituted by a halogen atom, a hydroxyl group, a carboxyl group, a nitro group, a cyano group or-NR³R⁴The hydrocarbon group in the hydrocarbon group, the acyl group and the alkoxy group may be interrupted by an ether bond, a thioether bond, an ester bond, a thioester bond, an amide bond or a urethane bond. R²Represents an alkyl group having 1 to 5 carbon atoms. Wherein means that the bond between the onium moiety and the adjacent group is present. R²Preferably methyl.

The photosensitive resin composition of the present invention is preferably a photosensitive resin composition in which the oxime ester photopolymerization initiator (d) contains at least 1 or more kinds of photopolymerization initiators (d-2) having a structure represented by the following general formula (3) and having a molar absorption coefficient at a wavelength of 405nm of 1000L/(mol cm) or more.

(in the general formula (3), R¹Represents a halogen atom, a hydroxyl group, a carboxyl group, a nitro group, a cyano group, -NR³R⁴A C1-valent hydrocarbon group of 1 to 20, a C1-20 acyl group or a C1-20 alkoxy group, R³And R⁴Each independently represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms. Wherein at least a part of the hydrogen atoms of the hydrocarbon group, the acyl group and the alkoxy group may be substituted by a halogen atom, a hydroxyl group, a carboxyl group, a nitro group, a cyano group or-NR³R⁴The hydrocarbon group in the hydrocarbon group, the acyl group and the alkoxy group may be interrupted by an ether bond, a thioether bond, an ester bond, a thioester bond, an amide bond or a urethane bond. R²Represents an alkyl group having 1 to 5 carbon atoms. Wherein means that the bond between the onium moiety and the adjacent group is present. ) R is²Preferably methyl.

The photopolymerization initiator (d-1) is preferably a structure represented by the following general formula (4).

In the general formula (4), R⁵～R⁷Each independently represents a halogen atom, a hydroxyl group, a carboxyl group, a nitro group, a cyano group, -NR⁹R¹⁰A C1-valent hydrocarbon group of 1 to 20, a C1-20 acyl group or a C1-20 alkoxy group, R⁹And R¹⁰Each independently represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms. Wherein at least a part of the hydrogen atoms of the hydrocarbon group, the acyl group and the alkoxy group may be substituted by a halogen atom, a hydroxyl group, a carboxyl group, a nitro group, a cyano group or-NR⁹R¹⁰The hydrocarbon group in the hydrocarbon group, the acyl group and the alkoxy group may be interrupted by an ether bond, a thioether bond, an ester bond, a thioester bond, an amide bond or a urethane bond. R⁸Represents an alkyl group having 1 to 5 carbon atoms. Among them, R⁵Preferably C1-20 acyl or C1-20 alkoxy, more preferably C1-10 acyl or C1-10 alkoxy, and more preferably C1-10 acyl. The acyl group preferably has at least one of an aromatic ring and an ether bond. The alkoxy group is preferably an alkoxy group in which a part of hydrogen atoms is substituted with a hydroxyl group. R⁷Preferably a C1-valent hydrocarbon group of 1 to 20, more preferably a C1-valent hydrocarbon group of 1 to 10. R⁸Preferably methyl.

In the general formula (2), a represents an integer of 0 to 5, and b represents an integer of 0 to 4. A represents CO or a direct bond. a is preferably "1", b is preferably "0", and a is preferably a direct bond.

Examples of the photopolymerization initiator (d-1) include compounds described in International publication No. 2012/002028 and compounds described in International publication No. 2015/036910.

The photopolymerization initiator (d-2) is preferably a structure represented by the following general formula (5).

In the general formula (5), R¹¹～R¹³Each independently represents a halogen atom, a hydroxyl group, a carboxyl group, a nitro group, a cyano group, -NR¹⁵R¹⁶A C1-valent hydrocarbon group of 1 to 20, a C1-20 acyl group or a C1-20 alkoxy group, R¹⁵And R¹⁶Each independently represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms. Wherein at least a part of the hydrogen atoms of the hydrocarbon group, the acyl group and the alkoxy group may be substituted by a halogen atom, a hydroxyl group, a carboxyl group, a nitro group, a cyano group or-NR¹⁵R¹⁶The hydrocarbon group in the hydrocarbon group, the acyl group and the alkoxy group may be interrupted by an ether bond, a thioether bond, an ester bond, a thioester bond, an amide bond or a urethane bond. R¹⁴Represents an alkyl group having 1 to 5 carbon atoms. Among them, R¹¹Preferably nitro. R¹³Preferably has at least one of an aromatic ring and an ether bond. R¹⁴Preferably methyl.

In the general formula (5), e represents an integer of 0 to 4, and f represents an integer of 0 to 3. B represents CO or a direct bond. D represents-N (R)¹⁷) -or-C (R)¹⁸)(R¹⁹)-。R¹⁷～R¹⁹Each independently represents a hydrogen atom or a 1-valent hydrocarbon substituent having 1 to 10 carbon atoms. e is preferably "1" and f is preferably "0". B is preferably a direct bond. D is preferably-N (R)¹⁷)-，R¹⁷More preferably an alkyl chain having 5 or less carbon atoms.

The molar absorption coefficient at a wavelength of 405nm of the photopolymerization initiator (d-2) is preferably 1000L/(mol. cm) or more, more preferably 2000L/(mol. cm) or more, and still more preferably 3000L/(mol. cm) or more, from the viewpoint of improving the surface curability of the photosensitive resin composition.

Examples of the photopolymerization initiator (d-2) include several compounds described in International publication No. 2008/078678.

From the viewpoint of effectively advancing the photocuring reaction of the unsaturated bond-containing compound (b) upon exposure, the total amount of the photopolymerization initiator (d-1) and the photopolymerization initiator (d-2) in the photosensitive resin composition of the invention is preferably 1 part by mass or more, more preferably 3 parts by mass or more, further preferably 4 parts by mass or more, and most preferably 7 parts by mass or more, per 100 parts by mass of the alkali-soluble polyimide (a).

From the viewpoint of further improving the transmittance of the photosensitive resin composition and suppressing excessive polymerization reaction, the total amount of the photopolymerization initiator (d-1) and the photopolymerization initiator (d-2) is preferably 30 parts by mass or less, more preferably 20 parts by mass or less, further preferably 15 parts by mass or less, and most preferably 10 parts by mass or less, relative to 100 parts by mass of the alkali-soluble polyimide (a).

The content of the photopolymerization initiator (d-2) in the photosensitive resin composition of the present invention is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, and still more preferably 20 parts by mass or more, per 100 parts by mass of the photopolymerization initiator (d-1), from the viewpoint of improving the sensitivity of the photosensitive resin composition. On the other hand, the content of the photopolymerization initiator (d-2) is preferably 50 parts by mass or less, more preferably 40 parts by mass or less, and still more preferably 30 parts by mass or less, per 100 parts by mass of the photopolymerization initiator (d-1), from the viewpoints of improvement in resolution and easy processing of a pattern shape into a forward tapered shape or a rectangular shape.

The content of the photopolymerization initiator (d-2) in the photosensitive resin composition of the present invention is more preferably 5 to 50 parts by mass, and still more preferably 10 to 30 parts by mass, based on 100 parts by mass of the photopolymerization initiator (d-1).

(sensitizer)

The photosensitive resin composition of the present invention may further contain a sensitizer (e). By using the sensitizer (e), the photopolymerization initiator (d-1) and the photopolymerization initiator (d-2) are efficiently sensitized, and the sensitivity is further improved.

The sensitizer (e) is preferably a thioxanthone compound, preferably thioxanthone, 2-methylthioxanthone, 2-ethylthioxanthone, 2-propylthioxanthone, 4-methylthioxanthone, 4-ethylthioxanthone, 4-propylthioxanthone, 2-methyl-4-ethylthioxanthone, 2-ethyl-4-propylthioxanthone, 2-ethyl-4-methylthioxanthone, 2-ethyl-4-propylthioxanthone, 2-propyl-4-methylthioxanthone, 2-propyl-4-ethylthioxanthone, 2, 4-dimethylthioxanthone, 2, 4-diethylthioxanthone, 2, 4-dipropylthioxanthone, or the like.

The content of the sensitizer (e) in the photosensitive resin composition of the present invention is preferably 1 part by mass or more, and more preferably 5 parts by mass or more, per 100 parts by mass of the total amount of the photopolymerization initiator (d-1) and the photopolymerization initiator (d-2), from the viewpoint of improving the sensitivity of the photosensitive resin composition. On the other hand, the content of the sensitizer (e) is preferably 20 parts by mass or less, more preferably 15 parts by mass or less, based on 100 parts by mass of the total amount of the photopolymerization initiator (d-1) and the photopolymerization initiator (d-2), from the viewpoint of efficiently expressing the photosensitizing effect of light and improving the sensitivity of the photosensitive resin composition.

(Filler)

The photosensitive resin composition of the present invention may further contain a filler (f). By using the filler (f), mechanical properties such as elastic modulus and chemical resistance can be improved. This makes it easy to maintain the shape of the hollow cap and also suppresses cracks. Examples of the filler (f) include silicon oxides such as talc, amorphous silica, crystalline silica, fused silica and spherical silica, titanium oxide, aluminum oxide, calcium oxide, magnesium oxide, zinc oxide, calcium carbonate, magnesium carbonate, fly ash, dehydrated sludge, natural silica, synthetic silica, kaolin, clay, calcium hydroxide, aluminum hydroxide, magnesium hydroxide, mica, hydrotalcite, aluminum silicate, magnesium silicate, calcium silicate, calcined talc, wollastonite, potassium titanate, magnesium sulfate, calcium sulfate, magnesium phosphate, sepiolite, calcined vermiculite, boron nitride, aluminum borate, glass, silica spheres, glass spheres, iron-making slag, copper, iron oxide, iron-silicon-aluminum-magnetic alloy (sendust), alnico magnet (alnico magnet), magnetic powders such as various ferrites, cement, nonopau silica, diatomaceous earth, antimony trioxide, Basic magnesium sulfate (magnesium oxysulfate), hydrated aluminum, hydrated gypsum, alum, barium sulfate and the like.

Among them, glass is preferable as the filler (f) in view of suppressing light scattering by adjusting the refractive index and improving the resolution.

From the viewpoint of matching with the refractive index of the resin, the refractive index of the glass at a wavelength of 405nm is preferably 1.55 to 1.75.

The glass contains silica and alumina, and preferably the glass further contains yttria and/or a lanthanide oxide. The glass preferably contains a small amount of magnesium oxide, calcium oxide, and zinc oxide, which cause elution of components due to the influence of humidity, and more preferably does not contain any of these. Further, from the viewpoint of insulation reliability, the glass further preferably does not contain an alkali metal oxide. In addition, the glass preferably further contains boron oxide from the viewpoint of ease of melting of the glass, and the glass preferably contains yttrium oxide among lanthanoid oxide and yttrium oxide from the viewpoint of ease of obtaining raw materials.

As described above, since the glass preferably has a small content of magnesium oxide, calcium oxide, and zinc oxide, the total amount of magnesium ions, calcium ions, and zinc ions detected from an extract obtained by subjecting the glass to extraction treatment under a saturated water vapor pressure condition of 121 ℃ for 24 hours is preferably 100ppm (by weight) or less in the glass. The measurement can be performed by the following method. A glass (3 g) and ultrapure water (30 mL) were put into the vessel, the vessel was sealed, and the vessel was placed in a thermostat at 121 ℃ to conduct extraction treatment for 24 hours. The obtained extract was analyzed by an ion chromatography apparatus, and the amount of each ion extracted was converted from a calibration curve of a standard solution using each ion.

In order to obtain a glass in which the total amount of magnesium ions, calcium ions, and zinc ions detected from an extract liquid extracted at 121 ℃ for 24 hours is 100ppm (by weight) or less in the glass, and the refractive index at 405nm is 1.55 to 1.75, the content of the total of yttrium oxide and a lanthanoid oxide in 100 parts by mass of the glass is preferably 15 to 35 parts by mass, and more preferably 40 to 50 parts by mass of silicon oxide, 20 to 30 parts by mass of aluminum oxide, 15 to 35 parts by mass of the total of yttrium oxide and a lanthanoid oxide, and 0 to 10 parts by mass of boron oxide are contained in 100 parts by mass of the glass. The above-mentioned content of the total of yttrium oxide and lanthanoid oxide in 100 parts by mass of the glass is 15 to 35 parts by mass, and means that when the glass contains only one of yttrium oxide and lanthanoid oxide, the content of the one is 15 to 35 parts by mass.

The glass in the present invention is a material that does not have a sharp peak (half width 2 ° or less) of a crystal structure in which a specific component appears in a powder X-ray diffraction measurement of 2 θ - θ.

The refractive index of the glass can be measured by the Becker method, and in the present invention, the refractive index is measured at a wavelength of 405 nm. When the difference in refractive index between the glass and the organic component of the photosensitive resin composition is large, reflection and scattering occur at the interface, and thus the resolution is reduced. In order to obtain a good resolution, the absolute value of the difference between the refractive index of the (B) glass and the refractive index of the organic component of the photosensitive resin composition is preferably 0.05 or less. The refractive index of the organic component of the photosensitive resin composition largely depends on the refractive index of the soluble polymer, and in the case of the alkali-soluble polyimide (a), the refractive index is 1.55 to 1.75. The refractive index of the organic component of the photosensitive resin composition can be determined by modulating only the organic component of the photosensitive resin composition, and measuring light having a wavelength of 405nm at 25 ℃ by an ellipsometry method after the coating and drying steps.

The average particle diameter of the filler (f) is preferably 10nm or more. By setting the average particle diameter to 10nm or more, the filler can be easily added, and high filling can be achieved. On the other hand, the average particle diameter of the filler (f) is preferably 2 μm or less, more preferably 1 μm or less, and further preferably 100nm or less. The smaller the average particle size, the more smooth the surface of the insulating film after patterning becomes, and light scattering is suppressed, thereby improving the resolution. The average particle diameter of the filler (f) is more preferably 10 to 100 nm.

The average particle diameter of the filler (f) in the present invention is a value of 50% volume particle diameter measured by using a particle size distribution meter (マイクロトラック particle size analyzer MODEL MT3000) by a laser diffraction scattering method. The measurement was carried out by taking about 1g of a sample and dispersing the sample in purified water for 1 to 3 minutes by ultrasonic waves of 40W output.

The shape of the filler (f) is not particularly limited, but is preferably spherical in view of increasing the amount of the filler added to the photosensitive resin composition and providing excellent smoothness of the insulating film obtained by patterning the photosensitive resin composition.

The content of the filler (f) used in the photosensitive resin composition of the present invention is preferably 30 parts by mass or more, and more preferably 60 parts by mass or more, per 100 parts by mass of the solid content of the photosensitive resin composition, from the viewpoint of improving mechanical properties such as elastic modulus and chemical resistance.

In addition, in order to disperse the filler (f) in the photosensitive resin composition, surface treatment with a silane coupling agent may be performed as necessary. Specific examples of the silane coupling agent include vinyltrimethoxysilane (KBM-1003), 3-glycidoxypropyltrimethoxysilane (KBM-403), 3-methacryloxypropyltrimethoxysilane (KBM-503), N-2- (aminoethyl) -3-aminopropyltrimethoxysilane (KBM-603), and N-phenyl-3-aminopropyltrimethoxysilane (KBM-603) which are known in the Beacon chemical industry. The surface treatment of the filler (f) can be performed by a dry surface treatment in which a silane coupling agent and a small amount of water are added to the filler (f) and stirred.

(other Inclusion substances)

The photosensitive resin composition of the present invention may further contain additives such as a crosslinking agent other than the thermally crosslinkable compound (c), a photopolymerization initiator other than the photopolymerization initiator (d-1) and the photopolymerization initiator (d-2), a thermal polymerization initiator, a polymerization inhibitor, a colorant, a surfactant, a silane coupling agent, a titanium chelating agent, a crosslinking accelerator, a dissolution regulator, a stabilizer, a defoaming agent, and an organic solvent, as required.

Examples of the photopolymerization initiator other than the photopolymerization initiator (d-1) and the photopolymerization initiator (d-2) include oximes, benzophenones, benzylidenes, coumarins, anthraquinones, benzoins, thioxanthones, sulfhydryls, glycin oximes, benzildimethylketals, α -hydroxyalkylbenzenes, α -aminoalkylbenzophenones, acylphosphine oxides, and 2,2 ' -bis (o-chlorophenyl) -4,4 ', 5,5 ' -tetraphenylbenzimidazole. The photosensitive resin composition of the present invention may contain 2 or more of the above-mentioned compounds as photopolymerization initiators other than the photopolymerization initiator (d-1) and the photopolymerization initiator (d-2).

Among them, oximes and acylphosphine oxides are preferable. Examples of the oximes include 1-phenyl-1, 2-butanedione-2- (O-methoxycarbonyl) oxime, 1-phenyl-1, 2-propanedione-2- (O-ethoxycarbonyl) oxime, 1-phenyl-1, 2-propanedione-2- (O-benzoyl) oxime, bis (. alpha. -isonitrosoprophenoxime) isophthaloyl, 1- [4- (phenylthio) phenyl ] -1, 2-octanedione 2- (O-benzoyloxime), and 1- [ 9-ethyl-6- (2-methylbenzoyl) -9H-carbazole-3- Yl ] ethanone 1- (O-acetyloxime), and the like. Examples of acylphosphine oxides include 2,4, 6-trimethylbenzoyldiphenyl-phosphine oxide, bis (2,4, 6-trimethylbenzoyl) -phenylphosphine oxide, and the like.

The photosensitive resin composition of the present invention contains a polymerization inhibitor to adjust the concentration of excitons, and therefore, can suppress excessive photoresponsiveness and widen the exposure margin. The photosensitive resin composition of the present invention contains a colorant, and thus exhibits an effect of suppressing stray light from a light-emitting region when used for an insulating layer of an organic electroluminescent element, and exhibits a hiding effect of hiding circuit wiring on a circuit board when used for a solder resist for a circuit board. Examples of the colorant include dyes and pigments. Examples of the dye include a thermochromatic dye. Examples of the pigment include inorganic pigments and organic pigments. As such a colorant, a substance that is soluble in an organic solvent that dissolves the alkali-soluble polyimide (a) and is compatible with the alkali-soluble polyimide (a) is preferable.

The photosensitive resin composition of the present invention contains a surfactant, a silane coupling agent, a titanium chelating agent, and the like, and thus can improve adhesion to a substrate. The organic solvent in the present invention is preferably one that dissolves the photosensitive resin composition. Examples of such organic solvents include ethers, acetates, ketones, aromatic hydrocarbons, N-methyl-2-pyrrolidone, N-cyclohexyl-2-pyrrolidone, N-dimethylformamide, N-dimethylacetamide, dimethylsulfoxide, and γ -butyrolactone. The photosensitive resin composition of the present invention may contain 2 or more of these as an organic solvent.

Examples of the ethers include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, and ethylene glycol dibutyl ether. Examples of the acetates include ethylene glycol monoethylether acetate, propylene glycol monomethyl ether acetate, propyl acetate, butyl acetate, isobutyl acetate, 3-methoxybutyl acetate, 3-methyl-3-methoxybutyl acetate, methyl lactate, ethyl lactate, and butyl lactate. Examples of the ketones include acetone, methyl ethyl ketone, acetylacetone, methyl propyl ketone, methyl butyl ketone, methyl isobutyl ketone, cyclopentanone, and 2-heptanone. Examples of the aromatic hydrocarbons include alcohols such as butanol, isobutanol, pentanol, 4-methyl-2-pentanol, 3-methyl-2-butanol, 3-methyl-3-methoxybutanol, and diacetone alcohol, toluene, and xylene.

< method for producing photosensitive resin composition >

The photosensitive resin composition of the present invention can be obtained by, for example, mixing and dissolving an alkali-soluble polyimide (a), a compound (b) having an unsaturated bond, a thermally crosslinkable compound (c), a photopolymerization initiator (d-1), a photopolymerization initiator (d-2), and if necessary, a sensitizer (e) and other additives. The photosensitive resin composition of the present invention can be obtained by, for example, mixing and dissolving a photosensitive resin composition containing an alkali-soluble polyimide (a), a compound (b) having an unsaturated bond, a thermally crosslinkable compound (c), 2 or more oxime ester photopolymerization initiators (d), and, if necessary, a sensitizer (e) and other additives. The photosensitive resin composition of the present invention can be dissolved in an organic solvent as needed to prepare a solution having a solid content concentration of about 20 to 70 mass%.

The photosensitive resin composition of the present invention can be filtered by using a filter paper or a filter. The method of filtering the photosensitive resin composition is not particularly limited, and a method of filtering by pressure filtration using a filter having a retained particle diameter of 0.4 to 10 μm is preferable.

< form of photosensitive resin composition >

The form of the photosensitive resin composition of the present invention may be selected from a sheet form, a rod form, a spherical form, a granular form, and the like, depending on the application. The term "sheet" as used herein includes films, plates, and the like. In the present invention, the form of the photosensitive resin composition is preferably a sheet form. That is, the photosensitive resin composition of the present invention is preferably formed into a sheet-like photosensitive resin sheet.

The photosensitive resin sheet of the present invention can be obtained, for example, by coating the photosensitive resin composition of the present invention on a support and then drying it as necessary.

The photosensitive resin sheet of the present invention is preferably a photosensitive resin sheet comprising a support and a photosensitive resin layer formed on the support using a photosensitive resin composition.

Examples of the support include a polyethylene terephthalate (PET) film, a polyphenylene sulfide film, and a polyimide film. The bonding surface between the support and the photosensitive resin sheet may be subjected to surface treatment with silicone, a silane coupling agent, an aluminum chelating agent, polyurea, or the like, in order to improve the adhesion and releasability thereof.

From the viewpoint of workability, the thickness of the support is preferably 10 μm or more. On the other hand, the thickness of the support is preferably 50 μm or less, more preferably 40 μm or less, and particularly preferably 30 μm or less, from the viewpoint of reducing cracks in the photosensitive resin when the film is peeled.

Further, from the viewpoint of suppressing scattering of light and improving the resolution when the photosensitive resin layer is exposed to light through the support, the haze of the support at a wavelength of 405nmThe degree is preferably 1% or less. HAZE at wavelength of 405nm, i.e. HAZE₄₀₅The transmittance can be determined by measuring the transmittance with a spectrophotometer and substituting the transmittance into the following equation.

HAZE₄₀₅＝T2-T1

T1 represents the transmittance at a wavelength of 405nm measured without an integrating sphere in a spectrophotometer, and T2 represents the transmittance at a wavelength of 405nm measured with an integrating sphere in a spectrophotometer.

The photosensitive resin sheet of the present invention may have a protective film for protecting the photosensitive resin layer. The surface of the photosensitive resin layer can be protected from contaminants such as dust and dirt in the atmosphere by the protective film.

Examples of the protective film in the present invention include a polyethylene film, a polypropylene (PP) film, a polyester film, and a polyvinyl alcohol film. The protective film preferably has a peeling force to such an extent that the photosensitive resin layer and the protective film are not easily peeled.

Examples of the method of applying the photosensitive resin composition to a support for producing the photosensitive resin sheet of the present invention include methods such as spin coating, spray coating, roll coating, screen printing, knife coater, die coater, calender coater, meniscus coater, bar coater, roll coater, comma roll coater, gravure coater, screen coater, and slot die coater using a spin coater.

The coating film thickness of the photosensitive resin composition varies depending on the coating method, the solid content concentration of the photosensitive resin composition to be coated, the viscosity, and the like, but from the viewpoint of securing the thickness of the cured film, the film thickness after drying of the photosensitive resin composition is preferably adjusted to 0.5 μm or more, more preferably adjusted to 10 μm or more, and still more preferably adjusted to 12 μm or more. On the other hand, from the viewpoint of making the cured film thin, the film thickness of the photosensitive resin composition after drying is preferably adjusted to 150 μm or less, more preferably 100 μm or less, and still more preferably 50 μm or less. The thickness of the coating film of the photosensitive resin composition is more preferably 12 to 150 μm after the photosensitive resin is coated and dried on the substrate, and still more preferably 12 to 50 μm after the photosensitive resin is coated and dried on the substrate.

Examples of the drying device for drying the applied photosensitive resin composition include an oven, an electric heating plate, and infrared rays. The drying temperature and the drying time may be in a range in which the organic solvent can be volatilized, and preferably, a range in which the photosensitive resin sheet is in an uncured or semi-cured state is appropriately set. Specifically, the drying temperature is preferably in the range of 40 to 120 ℃, and the drying time is preferably in the range of 1 to several tens of minutes. Further, as for the drying temperature, the temperature in this range may be combined to be gradually increased. For example, in the drying of the photosensitive resin composition, the photosensitive resin composition can be heated at 50 ℃, 60 ℃, 70 ℃ for 1 minute.

< cured product of photosensitive resin composition >

The cured product of the photosensitive resin composition can be obtained by heat-curing the photosensitive resin composition of the present invention. In the heat curing of the photosensitive resin composition, the heat curing temperature is preferably in the range of 120 to 400 ℃. The form of the cured product of the photosensitive resin composition is not particularly limited, and a sheet, a rod, a sphere, a pellet, or the like can be selected according to the application. In the present invention, the cured product is preferably in the form of a film.

From the viewpoint of heat resistance and pressure resistance, it is preferable that the cured product obtained by the heat treatment has a high 180 ℃ elastic modulus. The higher the 180 ℃ elastic modulus of the cured film, the more easily the film can withstand the sealing step of the hollow structure. The cured product of the photosensitive resin composition of the present invention has an elastic modulus at 180 ℃ of preferably 3GPa or more, more preferably 5GPa or more, and still more preferably 7 GPa.

The cured product of the photosensitive resin composition of the present invention can be used suitably for the cap portion of the hollow structure because it can form the cap of the hollow structure with high sensitivity and ease. The shape of the cured product of the photosensitive resin composition may be selected by patterning the photosensitive resin composition according to the application, such as formation of a cap of the hollow structure, formation of a protective film on a wall surface, formation of a through hole for conduction, adjustment of impedance, electrostatic capacity or internal stress, and provision of a heat release function.

< example of processing photosensitive resin sheet >

Next, a method of forming a hollow structure by patterning the photosensitive resin sheet of the present invention will be described by way of example.

The method for manufacturing a hollow structure of the present invention comprises the steps of: a laminating step (A) of laminating a photosensitive resin sheet on a projection provided for forming a hollow structure on a substrate so as to form a cover of the hollow structure, thereby forming a photosensitive resin layer; an exposure step (B) of irradiating a predetermined portion of the photosensitive resin layer with active light to photocure the exposed portion; a baking step (C) for heating the photosensitive resin layer to accelerate curing of the exposed portion; a peeling step (D) of peeling off the support; a developing step (E) for removing the photosensitive resin layer except for the exposed portion by using a developer; and a thermosetting step (F) of thermally curing the exposed portion of the photosensitive resin layer to form a cured resin product. Through these steps, a desired pattern for producing a hollow cap can be formed on the convex portion of the substrate.

The respective steps will be explained below. Fig. 1 shows an example of a suitable processing method of the photosensitive resin sheet of the present invention.

(laminating step (A))

When the photosensitive resin sheet has a protective film, the protective film is peeled off. The photosensitive resin sheet and the substrate having the convex portion are arranged to face each other and bonded by thermocompression bonding. Fig. 1 (a) shows a lamination process. The convex portion of the substrate may be formed on the substrate by printing of a resin material or by photolithography of a photosensitive material, or the substrate may be shaved by a method such as dry etching to form a concave portion and the convex portion may be formed oppositely. The convex portion of the substrate is in contact with the outer wall of the hollow structure formed of the photosensitive resin, and a space surrounded by the convex portion is formed. The space surrounded by the convex part is, for example, a space having one side of 100 to 10,000 μm and a height of 5 μm or more and 100 μm or less. The space surrounded by the convex portion may have a convex portion continuous with the outer wall and an independent convex portion. It is preferable that functional portions of electronic components such as comb electrodes of an elastic wave filter and crystals of a crystal oscillator are provided inside the space surrounded by the convex portions. As the size and shape of the substrate, a circular substrate having a diameter of 100 to 300mm, a square substrate having a side of 100 to 300mm, or the like is used, and the convex portions are arranged on the whole surface or a part thereof. As a method of bonding the photosensitive resin layer, a press machine and a roll laminator can be mentioned, but a roll laminator capable of roll-to-roll continuous bonding is preferable from the viewpoint of mass productivity. The bonding temperature is preferably 40 ℃ or higher because the adhesiveness of the photosensitive resin layer is not sufficiently exhibited at an excessively low temperature, and is preferably 80 ℃ or lower because the photosensitive resin layer is excessively softened and adhered to the substrate at an excessively high temperature. Further, if the bonding pressure is too high, the photosensitive resin layer is excessively pressed and bonded to the substrate, and therefore, it is preferably 0.2MPa or less.

(Exposure step (B))

A mask having a desired pattern is formed on the photosensitive resin sheet formed by the above method, and the photosensitive resin sheet is exposed to a pattern by irradiating a chemical ray through the mask. Fig. 1 (B) shows an exposure process. Examples of the chemical radiation used for the exposure include ultraviolet rays, visible rays, electron beams, and X-rays. In the present invention, i-ray (365nm), h-ray (405nm) and g-ray (436nm) of a mercury lamp are preferably used. In the case where the support is made of a transparent material for these rays, exposure can be performed without peeling the support from the photosensitive resin sheet. From the viewpoint of suppressing the cracks of the photosensitive resin layer, it is preferable to expose the support without peeling it from the photosensitive resin sheet.

(baking Process (C))

When the formation of the hollow structure is facilitated, for example, the crack of the photosensitive resin layer is reduced and the sinking of the cover is reduced, it is preferable to perform the baking step (C) of heating the photosensitive resin sheet before development. Fig. 1 (C) shows a baking process. In the baking treatment, the baking temperature is preferably 50 ℃ or higher, more preferably 60 ℃ or higher, from the viewpoint of accelerating curing. On the other hand, the baking temperature is preferably 180 ℃ or less, more preferably 120 ℃ or less, from the viewpoint of reducing the trapping of the photosensitive resin layer. The baking temperature in the baking step (C) is more preferably 60 to 180 ℃. The baking time is preferably 5 seconds to several hours. In the baking step (C), the baking may be performed without peeling the support from the photosensitive resin sheet. From the viewpoint of suppressing the cracking and trapping of the photosensitive resin layer, it is preferable to bake without peeling the support.

(peeling step (D))

After the laminating step (a), the support is peeled off from the photosensitive resin layer. Fig. 1 (D) shows a peeling step. The peeling step (D) may be performed before or after the exposure step (B), and is preferably performed after the exposure step (B) from the viewpoint of suppressing the cracking of the photosensitive resin layer. The peeling step (D) may be performed before or after the baking step (C), and is preferably performed after the baking step (C) from the viewpoint of suppressing the trapping of the photosensitive resin layer.

(developing step (E))

Next, an unexposed portion of the photosensitive resin sheet is removed using a developing solution, and the photosensitive resin sheet is patterned. Fig. 1 (E) shows a developing process. The developer is preferably an aqueous solution of tetramethylammonium, or an aqueous solution of a compound exhibiting basicity such as diethanolamine, diethylaminoethanol, sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, triethylamine, diethylamine, methylamine, dimethylamine, dimethylaminoethyl acetate, dimethylaminoethanol, dimethylaminoethyl methacrylate, cyclohexylamine, ethylenediamine, 1, 6-hexamethylenediamine, or the like. If necessary, polar solvents such as N-methyl-2-pyrrolidone, N-dimethylformamide, N-dimethylacetamide, dimethylsulfoxide, γ -butyrolactone, and dimethylacrylamide, alcohols such as methanol, ethanol, and isopropanol, esters such as ethyl lactate and propylene glycol monomethyl ether acetate, and ketones such as cyclopentanone, cyclohexanone, isobutyl ketone, and methyl isobutyl ketone may be added to these aqueous alkaline solutions.

Examples of the developing method of the photosensitive resin sheet include a method of spraying the above-mentioned developer onto a film surface, a method of immersing the film surface in the developer, a method of applying ultrasonic waves while immersing the film surface in the developer, and a method of spraying the developer while rotating a substrate. The "film surface" herein refers to a surface of the substrate portion covered with the patterned photosensitive resin sheet among the substrate surfaces. Conditions such as the developing time and the temperature of the developing solution may be set within a range in which the unexposed portion of the photosensitive resin sheet can be removed. In order to process fine patterns in the photosensitive resin sheet and remove residues between the patterns, the photosensitive resin sheet may be further developed after the unexposed portions are removed.

(washing step)

After the development of the photosensitive resin sheet, the substrate may be subjected to a rinsing treatment. The rinsing liquid used for this rinsing treatment is preferably water. If necessary, alcohols such as ethanol and isopropyl alcohol, esters such as ethyl lactate and propylene glycol monomethyl ether acetate, and the like may be added to the rinse solution (water).

(Heat curing step (F))

After the photosensitive resin sheet is developed, the photosensitive resin sheet on the substrate is heat-treated at a temperature of 120 to 400 ℃ to form a cured film. Fig. 1 (F) shows a thermosetting process. The heat treatment (cure) may be performed by gradually raising the temperature by selecting the temperature, or may be performed by continuously raising the temperature by selecting a certain temperature range. In this heat treatment, the heating temperature is more preferably 150 ℃ or higher, and still more preferably 180 ℃ or higher. On the other hand, the heating temperature is preferably 300 ℃ or less, more preferably 250 ℃ or less. The heat treatment time is preferably 5 minutes to 5 hours. Examples of the heat treatment include a method of heat treatment at 130 ℃ and 200 ℃ for 30 minutes, and a method of linearly raising the temperature from room temperature to 250 ℃ over 2 hours.

< hollow structure >

The hollow structure of the present invention is a hollow structure formed by a projection and a cover provided on a substrate of an electronic component, and the cover is a hollow structure formed by a photosensitive resin composition layer of a photosensitive resin sheet.

The film thickness of the cured product of the photosensitive resin composition is preferably 0.5 μm or more, more preferably 10 μm or more, and still more preferably 12 μm or more, from the viewpoint of maintaining the shape of the hollow structured cap. On the other hand, from the viewpoint of downsizing of the hollow structure, the film thickness of the cured product of the photosensitive resin composition is preferably 150 μm or less, more preferably 100 μm or less, and still more preferably 50 μm or less.

< electronic component >

The electronic component of the present invention has a hollow structure formed by a convex portion and a cover provided on a substrate of the electronic component, and the cover is composed of a photosensitive resin composition layer of a photosensitive resin sheet. The electronic component having a hollow structure includes an elastic wave filter, MEMS, and the like, and can be processed in a short time by applying the photosensitive resin sheet of the present invention. The elastic wave filter is a noise removing filter for extracting only a signal of a specific frequency by using vibration of a piezoelectric body. Since the elastic wave filter requires a space for vibrating the piezoelectric body and the electrode, a hollow structure covering and surrounding the piezoelectric body and the electrode as shown in fig. 1 is necessary.

Examples

The present invention will be specifically described below with reference to examples and comparative examples. The alkali-soluble polyimide (a), the photopolymerization initiator (d-1) and the photopolymerization initiator (d-2) used in each of the following examples and comparative examples were synthesized by the following methods.

(Synthesis example 1)

A method for synthesizing polyimide a1, which is an alkali-soluble polyimide (a), in synthesis example 1 of the present invention will be described. In the method for synthesizing polyimide a1, 2-bis (3-amino-4-hydroxyphenyl) hexafluoropropane (32.96g (0.090 mol)) and 1, 3-bis (3-aminopropyl) tetramethyldisiloxane (1.24g (0.005 mol)) were dissolved in N-methyl-2-pyrrolidone (100g) under a dry nitrogen gas flow. Hereinafter, "N-methyl-2-pyrrolidone" is referred to as "NMP". To this solution was added bis (3, 4-dicarboxyphenyl) ether dianhydride (31.02g (0.100 mol)) together with NMP (30g), and the mixture was stirred at 20 ℃ for 1 hour and then at 50 ℃ for 4 hours. To the stirred solution was added 3-aminophenol (1.09g (0.010 mol)), and the mixture was stirred at 50 ℃ for 2 hours and then at 180 ℃ for 5 hours to obtain a resin solution. Then, the resin solution was poured into water (3L) to form a white precipitate. The white precipitate was collected by filtration, washed 3 times with water, and dried for 5 hours with a vacuum drier at 80 ℃. As a result, a powder of alkali-soluble polyimide (polyimide a1) having a structure represented by general formula (4) was obtained.

The imidization rate of the obtained polyimide a1 was 94%. The polyimide A1 had a solubility in an aqueous tetramethylammonium solution (2.38 mass%) at 23 ℃ of 0.1g/100g or more.

(Synthesis example 2)

A photopolymerization initiator B1 having the following chemical structure was synthesized as a photopolymerization initiator (d-1) in Synthesis example 2 of the present invention by the method described in International publication No. 2015/036910.

(Synthesis example 3)

A photopolymerization initiator B2 having the following chemical structure was synthesized as the photopolymerization initiator (d-1) in Synthesis example 3 of the present invention by the method described in International publication No. 2012/002028.

(Synthesis example 4)

A photopolymerization initiator C1 having the following chemical structure was synthesized as the photopolymerization initiator (d-2) in Synthesis example 4 of the present invention by the method described in International publication No. 2008/078678.

(other materials)

On the other hand, other materials used in the following examples and comparative examples are as follows.

As the compound (b) having an unsaturated bond, BP-6EM (trade name, manufactured by Kyoeisha chemical Co., Ltd., ethylene oxide-modified bisphenol A dimethacrylate) and MOI-BP (trade name, manufactured by Showa Denko K.K., 2- [ (3, 5-dimethylpyrazolyl) carbonylamino ] ethyl methacrylate) were used.

As the thermally crosslinkable compound (c), HMOM-TPHAP (trade name, manufactured by chemical industries, Japan, 4,4 '-ethylidenetris [2,6-bis (methoxymethyl) phenol ] (4, 4' -ethylidenetris [2,6-bis (methoxymethyl) phenol ])) was used.

As the photopolymerization initiator other than the photopolymerization initiator (d-1) and the photopolymerization initiator (d-2), that is, the other photopolymerization initiator (d'), there are used "IRGACURE" (registered trademark) OXE01 (trade name, manufactured by BASF, 1- [4- (phenylthio) phenyl ] -1, 2-octanedione 2- (O-benzoyloxime) "as an oxime ester type photopolymerization initiator," IRGACURE "OXE 02 (trade name, manufactured by BASF, 1- [ 9-ethyl-6- (2-methylbenzoyl) -9H-carbazol-3-yl ] -ethanone 1- (O-acetyloxime)") as an oxime ester type photopolymerization initiator, and "IRGACURE" 369 (trade name, manufactured by BASF, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -one) as a non-oxime ester type photopolymerization initiator 1-butanone).

DETX-S (trade name, 2, 4-diethylthioxanthen-9-one, manufactured by Nippon Kagaku Co., Ltd.) was used as the sensitizer (e).

The following 3 types of fillers (f) were used.

ガラス1：

45% by weight of silica, 25% by weight of alumina, 4% by weight of boron oxide, 26% by weight of yttrium oxide, a refractive index (wavelength 405nm) of 1.61, an average particle diameter of 1.2 μm, and an extracted ion amount (magnesium ion + calcium ion + zinc ion) of 7ppm (weight basis)

サブシリカ1：

SO-E2 (trade name, manufactured by アドマテックス Co., Ltd.), refractive index (wavelength 405nm)1.47, average particle diameter 0.5 μm, extracted ion amount (magnesium ion + calcium ion + zinc ion) 2ppm (based on weight)

ナノシリカ1：

YA050C (trade name, アドマテックス Co., Ltd.), refractive index (wavelength 405nm)1.47, average particle diameter 50nm, and extracted ion amount (magnesium ion + calcium ion + zinc ion) 2ppm (weight basis)

In each of the following examples and comparative examples, the other additive (g) is a silane coupling agent. As the silane coupling agent, IM-1000 (trade name, manufactured by JX Nikkiso Metal Co., Ltd.) was used.

The photopolymerization initiators and the evaluation methods in the following examples and comparative examples are as follows.

< photobleaching of photopolymerization initiator >

The photopolymerization initiator B1 was dissolved in ethyl lactate and adjusted so that the concentration thereof became 0.1 g/L. Then, the mixture was poured into a quartz cell having a thickness of 0.2cm, and the absorbance before exposure was measured using a spectrophotometer (manufactured by Hitachi ハイテクサイエンス, U-3900). Then, the resultant was exposed to 1000mJ/cm using an exposure apparatus (SME-150 GA-TRJ, manufactured by QINGHI OPTICAL CORPORATION)²The quartz cell with the solution added was exposed (i-ray conversion). Then, the absorbance after exposure was measured using a spectrophotometer (manufactured by Hitachi ハイテクサイエンス, U-3900). When the absorbance at the maximum absorption wavelength before exposure is assumed to be 100%, the absorbance Abs before exposure (before exposure) at which the absorbance in the long wavelength region is 20% higher than the maximum absorption wavelength is obtained. In the case where there are two or more maximum absorption wavelengths, the maximum absorption wavelength in the long wavelength region is used. Next, absorbance Abs (after exposure) after exposure at the same wavelength as Abs (before exposure) was obtained, and Abs (before exposure) and Abs (after exposure) were compared. The photobleaching performance was evaluated according to the following criteria. Other photopolymerization initiators were also evaluated by the same method. The evaluation results of the respective photopolymerization initiators are shown in table 1 below.

Comprises the following steps: abs (before exposure) > Abs (after exposure), photobleachable.

None: abs (before exposure) is less than or equal to Abs (after exposure), and no photobleaching.

< molar absorptivity of photopolymerization initiator >

The photopolymerization initiator B1 was dissolved in ethyl lactate and adjusted so that the concentration thereof became 0.1 g/L. Then, the mixture was poured into a quartz cell having a thickness of 0.2cm, and the absorbance Abs at a wavelength of 405nm was measured using a spectrophotometer (manufactured by Hitachi ハイテクサイエンス, U-3900)₄₀₅. For other photopolymerization initiators, Abs was also measured by the above-mentioned method₄₀₅. Then, the molar absorption coefficient ε at a wavelength of 405nm was calculated by the following Lambert beer formula₄₀₅. Other photopolymerization initiators were also evaluated by the same method. The evaluation results of the respective photopolymerization initiators are shown in table 1 below.

ε₄₀₅＝Abs₄₀₅/(C·l)

C represents the concentration of the solution, and l represents the optical path length of the measurement sample.

[ Table 1]

< resolution >

The protective film of the photosensitive resin sheet obtained in example 3 was peeled off, and the release surface layer of the photosensitive resin sheet was laminated on a 4-inch silicon wafer using a laminating apparatus (VTM-200M manufactured by タカトリ) under conditions of a platen temperature of 80 ℃, a roll temperature of 80 ℃, a vacuum degree of 150Pa, a bonding speed of 5 mm/sec, and a bonding pressure of 0.3 MPa. Using an exposure apparatus (SME-150 GA-TRJ, manufactured by QINGHI OPTICAL MAKING CO., LTD.) in a state where the support film was in contact with the photomask, the thickness of the support film was 300mJ/cm²(h-ray conversion) the exposure was performed. After peeling the support film, the substrate was subjected to a heat treatment at 200 ℃ for 1 hour in a nitrogen atmosphere having an oxygen concentration of 100ppm or less in an inert oven, to obtain a substrate having a resin film.

General purpose medicineThe protective film of the photosensitive resin sheet obtained in each example and each comparative example was peeled off, and the peeled surface of the photosensitive resin sheet was laminated on a substrate having a resin film by using a laminating apparatus (VTM-200M manufactured by タカトリ) under conditions of a platen temperature of 80 ℃, a roll temperature of 80 ℃, a vacuum degree of 150Pa, a bonding speed of 5 mm/sec, and a bonding pressure of 0.3 MPa. A photomask having a pattern of 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, and 100 μm Φ through a through hole was placed in an exposure apparatus (SME-150 GA-TRJ, manufactured by seikagaku corporation), and the support film was brought into contact with the photomask at 300mJ/cm²(h-ray conversion) the exposure was performed. After the exposure, the photosensitive resin layer was heated with a 70 ℃ hot plate for 10 minutes. Next, after the support film was peeled off, the unexposed portions of the photosensitive resin layer were removed by shower development for 60 seconds using a 2.38% aqueous solution of tetramethylammonium hydroxide. Further, the film was washed with water for 30 seconds and dried by spin drying. Then, the pattern formed on the photosensitive resin composition layer was observed with a microscope, and evaluated by the following criteria. A larger score means better and better resolution.

4: the minimum size of the through hole is 30 μm φ or less.

3: the minimum size of the through hole is 35 μm phi or more and 50 μm phi or less.

2: the minimum size of the through hole is 55 μm phi or more and 70 μm phi or less.

1: the minimum size of the via is 75 μm phi or more or the open via is not present.

< crack >

The protective film of the photosensitive resin sheet obtained in example 3 was peeled off, and the release surface layer of the photosensitive resin sheet was laminated on a 4-inch silicon wafer using a laminating apparatus (VTM-200M manufactured by タカトリ) under conditions of a platen temperature of 80 ℃, a roll temperature of 80 ℃, a vacuum degree of 150Pa, a bonding speed of 5 mm/sec, and a bonding pressure of 0.3 MPa. A mask in which 50 square patterns each having a width of 100 μm and a side of 500 μm were arranged in the vertical direction 50X in the horizontal direction 50 at intervals of 100 μm was placed in an exposure apparatus (SME-150 GA-TRJ, manufactured by QINGHI optical Co., Ltd.),in a state where the supporting film is in contact with the photomask, the thickness of the supporting film is 300mJ/cm²(h-ray conversion) the exposure was performed. After the exposure, the photosensitive resin layer was heated with a 70 ℃ hot plate for 10 minutes. Next, after the support film was peeled off, the unexposed portions of the photosensitive resin layer were removed by shower development for 60 seconds using a 2.38% aqueous solution of tetramethylammonium hydroxide. Further, the film was washed with water for 30 seconds and dried by spin drying. Then, the substrate was subjected to a heat treatment at 200 ℃ for 1 hour after the atmosphere was changed to a nitrogen atmosphere having an oxygen concentration of 100ppm or less in an inert oven, thereby obtaining a substrate on which a convex pattern was formed. Fig. 4 is a schematic view showing the convex pattern. Fig. 6 is a schematic view of a wafer on which a convex portion pattern is formed.

The protective film of the photosensitive resin sheet obtained in each example and each comparative example was peeled off, and the peeled surface of the photosensitive resin sheet was laminated on a substrate having a resin film by using a laminating apparatus (VTM-200M manufactured by タカトリ) at a platen temperature of 60 ℃, a roll temperature of 60 ℃, an adhesion speed of 20 mm/sec, an adhesion pressure of 0.1MPa, and an atmospheric pressure. A photomask in which 50 vertical and 50 horizontal square patterns each having a side of 600 μm were arranged at 200 μm intervals was placed in an exposure apparatus (SME-150 GA-TRJ, manufactured by QINGHI optical Co., Ltd.), and the photomask was placed at 300mJ/cm in a state where a support film was in contact with the photomask²(h-ray conversion) the exposure was performed. In this exposure, the position of the photomask is adjusted so that the center of the pattern of the cover is positioned at the center of the pattern of the convex portion, in order to form the hollow structure. After the exposure, the photosensitive resin layer was heated with a 70 ℃ hot plate for 10 minutes. Next, after the support film was peeled off, the unexposed portions of the photosensitive resin layer were removed by shower development for 60 seconds using a 2.38% aqueous solution of tetramethylammonium hydroxide. Further, the film was washed with water for 30 seconds and dried by spin drying. Then, the resultant was subjected to a heat treatment at 200 ℃ for 1 hour under a nitrogen atmosphere having an oxygen concentration of 100ppm or less in an inert oven to form a hollow structure. Fig. 5 is a schematic view showing a pattern of a cap formed on the convex portion pattern. Any 100 hollow structures in the substrate on which the hollow structures are formed are observed by a microscopeThe presence or absence of cracks in the lid made of the photosensitive resin layer was examined. Fig. 2 is a schematic view showing a crack in the photosensitive resin layer. The photosensitive resin layer that has been photo-cured by exposure to light is cracked and broken. The occurrence of cracks was calculated and evaluated by the following criteria. A larger score means less bad, and more excellent.

5: the incidence of cracks is less than 3%

4: the occurrence rate of cracks is 3% or more and less than 6%.

3: the occurrence rate of cracks is 6% or more and less than 10%.

2: the occurrence rate of cracks is 10% or more and less than 15%.

1: the incidence of cracks was 15% or more.

< trapping >

In any ten places of the hollow structure formed by the same method as in the case of the evaluation of the above-described crack, the bending of the cover composed of the photosensitive resin layer was measured from the cross-sectional view. Fig. 3 is a schematic view showing the bending of the cover formed of the photosensitive resin layer. The maximum bending of the lid was set as the bending amount with respect to the bonding surface of the convex portion and the photosensitive resin layer, and the average value was calculated. The calculated bending amount was evaluated by the following criteria. A larger score means a smaller, more excellent trap.

5: the amount of warpage is less than 3 μm.

4: the amount of warpage is 3 μm or more and less than 6 μm.

3: the amount of warpage is 6 μm or more and less than 10 μm.

2: the amount of warpage is 10 μm or more and less than 12 μm.

1: the amount of warpage is 12 μm or more.

< surface roughness/film reduction >

The presence or absence of surface roughening of the cover made of the photosensitive resin layer was confirmed by a microscope for the hollow structure formed by the same method as in the case of the evaluation of the crack. Further, the film thickness was measured by cross-sectional observation, and the film reduction of the cap composed of the photosensitive resin layer was evaluated by the following criteria. A larger score means better and more excellent surface curability.

3: the surface roughness was not generated, and the film thickness was 10 μm or more.

2: surface roughening has occurred and the film thickness is 10 μm or more.

1: surface roughening has occurred with a film thickness of less than 10 μm.

< Pattern shape >

The pattern shape of the cover formed of the photosensitive resin layer was observed in a cross section of the hollow structure formed by the same method as in the case of the evaluation of the crack. The taper angle formed by the convex portion and the side surface of the cap was measured, and the cross-sectional shape of the pattern was evaluated by the following criteria. A larger score means a better and more excellent pattern shape.

2: a rectangular or conical shape with a cone angle of 90 ° or less.

1: an inverted cone shape with a cone angle exceeding 90 deg..

Elastic modulus < 180 ℃ >

The photosensitive resin sheets obtained in each example and each comparative example were exposed to light at 300mJ/cm from the support side using an exposure apparatus (SME-150 GA-TRJ, manufactured by QINGHI optical Co., Ltd.)²(h-ray conversion) the exposure was performed. Then, the protective film was peeled off, and the resultant was subjected to a heat treatment at 200 ℃ for 1 hour after the atmosphere was changed to a nitrogen atmosphere having an oxygen concentration of 100ppm or less in an inert oven. Then, the support was peeled off to obtain a single film sample of a cured product. The single film sample was cut into 5 × 40mm with a single blade, and the sample length was measured using DMA (from hitachi ハイテクサイエンス, DMS 6100): 10mm, temperature conditions: the test was carried out at 25 ℃ → 350 ℃ (5 ℃/min), with a strain amplitude of 5 μm, a minimum tension/pressure of 10mN, a tension-pressure gain of 1.5, and an initial value of force amplitude of 50mN, and the elastic modulus at 180 ℃ was measured.

< example 1 >

In example 1 of the present invention, the polyimide A1 of Synthesis example 1 was used as the alkali-soluble polyimide (a), BP-6EM and MOI-BP were used as the unsaturated bond-containing compound (B), HMOM-TPHAP was used as the thermally crosslinkable compound (C), the photopolymerization initiator B1 of Synthesis example 2 was used as the photopolymerization initiator (d-1), and the photopolymerization initiator C1 of Synthesis example 4 was used as the photopolymerization initiator (d-2). Further, DETX-S was used as the sensitizer (e), and IM-1000 was used as the silane coupling agent.

Specifically, polyimide a1(35g), BP-6EM (15g), MOI-BP (5g), HMOM-TPHAP (6g), photopolymerization initiator B1(2g), photopolymerization initiator C1(0.05g), DETX-S (0.2g), and IM-1000(1g) were dissolved in a mixed solvent of diacetone alcohol/ethyl lactate (mass ratio) 30/70. The amount of the mixed solvent was adjusted so that the solid content concentration was 45 mass% by setting additives other than the solvent as solid contents. The obtained solution was subjected to pressure filtration using a filter having a retained particle diameter of 2 μm, thereby obtaining a photosensitive resin composition.

The obtained photosensitive resin composition was coated on a support film (a PET film having a thickness of 16 μm and a haze of 0.7% at a wavelength of 405nm) using a comma roll coater, dried at 75 ℃ for 5 minutes, and then laminated with a PP film having a thickness of 50 μm as a protective film, to obtain a photosensitive resin sheet having a thickness of 15 μm. Using the obtained photosensitive resin sheet, resolution, cracks, sink marks, surface roughness/film reduction, pattern shape, and 180 ℃ elastic modulus were evaluated by the above-described methods. The evaluation results of example 1 are shown in table 2 described below.

< examples 2 to 17, comparative examples 1 to 3 >

Photosensitive resin sheets were produced in the same manner as in example 1 except that in examples 2 to 17 of the present invention and comparative examples 1 to 3 of the present invention, the compositions in example 1 were changed to the compositions shown in tables 2 to 4, the thickness of the PET film as the base film, and the haze at a wavelength of 405 nm. Using the obtained photosensitive resin sheet, resolution, cracks, sink marks, surface roughness/film reduction, pattern shape, and 180 ℃ elastic modulus were evaluated by the above-described methods. The evaluation results of examples 2 to 17 and comparative examples 1 to 3 are shown in tables 2 to 4.

[ Table 2]

TABLE 2

[ Table 3]

TABLE 3

[ Table 4]

TABLE 4

As shown in tables 2 to 3, the results of evaluation were good in examples 1 to 17 using 2 or more oxime ester photopolymerization initiators (d). In examples 1 to 11 and 14 to 17 using the photopolymerization initiator (d-1) and the photopolymerization initiator (d-2), evaluation of cracks, sink marks, surface roughness, and film reduction was better than in examples 12 and 13. On the other hand, as shown in table 4, comparative examples 1 and 3 were inferior in evaluation of cracks and depressions to examples 1 to 17, and comparative example 2 was inferior in evaluation of resolution and pattern shape to examples 1 to 17.

Industrial applicability

The photosensitive resin composition of the present invention is a photosensitive resin composition which can pattern the lid portion of the hollow structure with high sensitivity and satisfactorily by photolithography. The photosensitive resin sheet of the present invention is suitable for a photosensitive resin sheet capable of patterning a cover portion of a hollow structure by photolithography with high sensitivity. Therefore, the photosensitive resin composition and the photosensitive resin sheet of the present invention are useful for the use of a hollow structure of an electronic component having a hollow structure as a cover, and specifically can be suitably used for the use of a hollow structure of an elastic wave filter as a cover.

Description of the symbols

1 piezoelectric substrate (substrate of piezoelectric body)

2 convex part

Comb-shaped electrode of 3 elastic wave filter (SAW filter)

4 support film

5 photosensitive resin layer

6 a photosensitive resin layer which is photo-cured by exposure to light.