阅读说明：本技术 密封用膜、密封结构体和密封结构体的制造方法 (Sealing film, sealing structure, and method for producing sealing structure ) 是由 野村丰 渡濑裕介 石毛纮之 铃木雅彦 于 2018-04-27 设计创作，主要内容包括：一种密封用膜,其由树脂组合物构成,上述树脂组合物含有热固性成分、无机填充材、和羧基当量为270～4300g/eq.的含羧基弹性体,以热固性成分与含羧基弹性体的合计量为基准计,含羧基弹性体的含量小于40质量％。(A sealing film comprising a resin composition containing a thermosetting component, an inorganic filler, and a carboxyl group-containing elastomer having a carboxyl group equivalent of 270 to 4300g/eq, wherein the content of the carboxyl group-containing elastomer is less than 40% by mass based on the total amount of the thermosetting component and the carboxyl group-containing elastomer.)

1. A sealing film comprising a resin composition containing a thermosetting component, an inorganic filler, and a carboxyl group-containing elastomer having a carboxyl group equivalent of 270 to 4300g/eq,

The content of the carboxyl group-containing elastomer is less than 40% by mass based on the total amount of the thermosetting component and the carboxyl group-containing elastomer.

2. The sealing film according to claim 1, wherein a content of the elastomer component containing the carboxyl group-containing elastomer contained in the resin composition is 2% by mass or more and less than 40% by mass based on a total amount of the thermosetting component and the elastomer component.

3. The sealing film according to claim 1 or 2, wherein the content of the structural unit having a carboxyl group in the carboxyl group-containing elastomer is 2 to 35 mol% based on the total amount of the structural units constituting the carboxyl group-containing elastomer.

4. The sealing film according to any one of claims 1 to 3, wherein the carboxyl group-containing elastomer comprises a structural unit derived from (meth) acrylic acid.

5. The sealing film according to any one of claims 1 to 4, wherein the weight average molecular weight of the carboxyl group-containing elastomer is 30 to 1000 ten thousand.

6. The sealing film according to any one of claims 1 to 5, wherein the thermosetting component comprises an epoxy resin and a phenol resin.

7. The sealing film according to any one of claims 1 to 6, wherein the content of the inorganic filler is 90% by mass or less based on the total mass of the sealing film.

8. The sealing film according to any one of claims 1 to 7, which has a film thickness of 20 to 400 μm.

9. The sealing film according to any one of claims 1 to 8, which is used for sealing a sealed body provided on a substrate with a bump interposed therebetween.

10. A method for manufacturing a sealing structure body,

Preparing a hollow structure body including a substrate and a sealed body provided on the substrate with a bump interposed therebetween, a hollow region being provided between the substrate and the sealed body;

Sealing the sealed body with the sealing film according to any one of claims 1 to 9.

11. The method of manufacturing a seal structure according to claim 10, wherein the sealed body is a SAW device having an electrode on the hollow region side.

12. A seal structure body is provided with: a cured product of the sealing film according to any one of claims 1 to 9, which comprises a substrate, a sealed body provided on the substrate via a bump, and the sealed body,

A hollow region is provided between the substrate and the sealed body.

13. the seal structure body according to claim 12, wherein the sealed body is a SAW device having an electrode on the hollow region side.

Technical Field

The present invention relates to a sealing film, a sealing structure, and a method for manufacturing a sealing structure.

Background

In recent years, with the development of electronic devices manufactured on the premise of being carried, such as smartphones, semiconductor devices have been reduced in size and thickness, and electronic component devices used therein have been required to be reduced in size and thickness. Therefore, various technologies for packaging electronic components having a movable portion such as a Surface Acoustic Wave (SAW) device have been studied. A SAW device is an electronic component in which a thin film of a piezoelectric body or a piezoelectric substrate is provided with an ordered comb-shaped electrode, and is capable of extracting an electric signal of a specific frequency band by using a surface acoustic wave.

When such an electronic component having a movable portion is packaged, a space for ensuring the mobility of the movable portion needs to be provided. For example, in the SAW device, if another substance adheres to the surface on which the comb-shaped electrode is formed, desired frequency characteristics cannot be obtained, and therefore, it is necessary to form a hollow structure.

Conventionally, in order to form a hollow structure, a sealing method has been performed in which a rib or the like is formed on a piezoelectric substrate and then a lid is closed (patent document 1). However, this method has a problem that it is difficult to make the electronic component device thin because the number of steps increases and the height of the sealing portion is high.

Therefore, the following methods are proposed: a hollow structure is prepared, and sealing of the chip is performed in a state where a hollow region is provided between the substrate and the chip, and the hollow structure is formed by flip-chip mounting the chip on which the comb-shaped electrode is formed on the substrate via bumps (for example, patent documents 2 and 3).

Disclosure of Invention

Problems to be solved by the invention

When a sealed body is sealed in a state where a hollow region is provided between a substrate and the sealed body to obtain a hollow sealed structure (for example, an electronic component device), it is necessary to suppress the flow of a sealing material (a resin composition constituting a sealing film) into the hollow region. On the other hand, in the methods of patent documents 2 and 3, since the elastomer component is contained at a high concentration, even if the flow of the sealing material into the hollow region can be suppressed, there is a concern that: the elastomer component greatly lowers the glass transition temperature (Tg) of the cured product, and the reliability (particularly, thermal reliability) of the hollow sealed structure is lowered. For example, it is presumed that when the thermosetting component and the elastomer component form a sea-island structure, Tg derived from the elastomer component exists in a low-temperature region, but since the thermal expansion coefficient of the resin changes greatly before and after Tg, a high concentration of the elastomer component becomes one cause of lowering the reliability of the hollow seal structure.

Accordingly, an object of the present invention is to provide a sealing film capable of sufficiently suppressing a sealing material from flowing into a hollow region between a substrate and a sealed body and forming a cured product having a sufficient glass transition temperature, a sealed structure using the sealing film, and a method for manufacturing the sealed structure.

Means for solving the problems

The present inventors have made studies on the premise that the smaller the amount of the elastomer component to be added, the better the Tg reduction can be avoided. From the viewpoint of sufficiently suppressing the inflow of the sealing material (resin composition constituting the sealing film) into the hollow region, the state and action of an ideal elastomer component are considered as follows.

(1) From the viewpoint that the elastomer component serves as resistance to the flow of the resin composition and can suppress the flow of the resin composition, the shape of the elastomer component in the resin composition is preferably linear as compared with the state of excessive winding (the line ま り).

(2) From the viewpoint that the flow of the resin component can be suppressed by restricting the flow of the resin composition by the elastomer component, it is preferable that the elastomer component is formed into a polymer in a pseudo manner by an intermolecular interaction.

The present inventors have conducted intensive studies based on the above viewpoints and as a result, have found that the use of an elastomer having a specific carboxyl equivalent weight can reduce the amount of an elastomer component to be added and sufficiently suppress the flow of a resin composition into a hollow region, thereby completing the present invention.

That is, one aspect of the present invention relates to a sealing film comprising a resin composition containing a thermosetting component, an inorganic filler, and a carboxyl group-containing elastomer having a carboxyl equivalent weight of 270 to 4300g/eq, wherein the content of the carboxyl group-containing elastomer is less than 40% by mass based on the total amount of the thermosetting component and the carboxyl group-containing elastomer. According to the sealing film, the sealing material can be sufficiently suppressed from flowing into the hollow region between the substrate and the sealed body. That is, the sealing film has excellent hollow non-filling properties. Further, according to the sealing film, a cured product having a sufficient glass transition temperature (Tg) can be formed.

The content of the elastomer component containing the carboxyl group-containing elastomer in the resin composition may be 2% by mass or more and 40% by mass or less, based on the total amount of the thermosetting component and the elastomer component. In this case, the hollow non-filling property is more excellent, and a more sufficient Tg is easily obtained after curing.

The content of the structural unit having a carboxyl group in the carboxyl group-containing elastomer may be 2 to 35 mol% based on the total amount of the structural units constituting the carboxyl group-containing elastomer. In this case, the hollow non-filling property is more excellent, and a more sufficient Tg is easily obtained after curing.

The above carboxyl group-containing elastomer may contain a structural unit derived from (meth) acrylic acid. In this case, the hollow non-filling property is more excellent, and a more sufficient Tg is easily obtained after curing.

The weight average molecular weight of the carboxyl group-containing elastomer may be 30 to 1000 ten thousand. In this case, the hollow non-filling property is more excellent, and a more sufficient Tg is easily obtained after curing.

The thermosetting component may include an epoxy resin and a phenol resin. In this case, the physical properties of the cured film (for example, heat resistance (Tg) and dimensional stability (thermal expansion coefficient)) and the reliability of the SAW device can be improved.

The content of the inorganic filler may be 90% by mass or less based on the total mass of the sealing film. In this case, excellent embedding properties with respect to the sealed body can be easily obtained.

The sealing film may have a film thickness of 20 to 400 μm.

The sealing film is suitably used for sealing a sealed body provided on a substrate with a bump interposed therebetween.

One aspect of the present invention relates to a method for manufacturing a sealed structure, including preparing a hollow structure, and sealing the sealed body with the sealing film of the present invention, the hollow structure including a substrate and a sealed body provided on the substrate with a bump interposed therebetween, and a hollow region provided between the substrate and the sealed body. According to this method, the sealing material can be sufficiently suppressed from flowing into the hollow region between the substrate and the sealed body. Further, since the sealed body can be sealed with a cured product having a sufficient Tg, a sealed structure having excellent reliability (thermal reliability) can be obtained.

In the above-described manufacturing method, the sealed body may be a SAW device having an electrode on the hollow region side. In the above manufacturing method, the adhesion of the sealing material to the surface of the SAW device having the electrode can be sufficiently suppressed, and the SAW device can be sealed with a cured product having a sufficient Tg. Therefore, according to the above manufacturing method, the reliability of the SAW device can be improved. For the same reason, the above-described manufacturing method can improve the yield in manufacturing a sealed structure (hollow sealed structure) including such a sealed body.

One aspect of the present invention relates to a sealed structure including a substrate, a sealed body provided on the substrate with a bump interposed therebetween, and a cured product of the sealing film of the present invention that seals the sealed body, wherein a hollow region is provided between the substrate and the sealed body. In the sealing structure, the hollow region is sufficiently secured, and the object to be sealed is sealed with a cured product having a sufficient Tg.

In the above-described seal structure, the sealed body may be a SAW device having an electrode on the hollow region side. In the sealing structure, adhesion of a sealing material to a surface of the SAW device having the electrode is sufficiently suppressed, and the SAW device is sealed with a cured product having a sufficient Tg. Therefore, the SAW device is excellent in reliability.

Effects of the invention

According to the present invention, it is possible to provide a sealing film capable of sufficiently suppressing a sealing material from flowing into a hollow region between a substrate and a sealed body and forming a cured product having a sufficient glass transition temperature, a sealed structure using the sealing film, and a method for manufacturing the sealed structure.

Drawings

Fig. 1 is a schematic cross-sectional view showing a sealing film with a support, which is provided with the sealing film according to the embodiment.

Fig. 2 is a schematic cross-sectional view for explaining an embodiment of a method for manufacturing a hollow seal structure.

FIG. 3 is a view showing a method for evaluating a flow rate in examples.

Detailed Description

In the present specification, a numerical range represented by "to" means a range including numerical values recited before and after "to" as a minimum value and a maximum value, respectively. In the numerical ranges recited in the present specification, the upper limit or the lower limit of the numerical range in a certain stage may be replaced with the upper limit or the lower limit of the numerical range in another stage. In the numerical ranges described in the present specification, the upper limit or the lower limit of the numerical range may be replaced with the values shown in the examples. "a or B" may include either or both of a and B. The materials exemplified in this specification may be used singly or in combination of two or more unless otherwise specified. In the present specification, the content of each component in the composition refers to the total amount of a plurality of substances present in the composition unless otherwise specified, when a plurality of substances corresponding to each component are present in the composition.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

< sealing film >

The sealing film of the present embodiment is a film-shaped resin composition containing a thermosetting component, an inorganic filler, and a carboxyl group-containing elastomer having a carboxyl group equivalent weight of 270 to 4300g/eq as an elastomer (flexibilizer) component. In the present embodiment, the content of the carboxyl group-containing elastomer having a carboxyl group equivalent of 270 to 4300g/eq may be less than 40% by mass based on the total amount of the thermosetting component and the carboxyl group-containing elastomer. In the present embodiment, the content of the elastomer component (including the carboxyl group-containing elastomer) contained in the resin composition may be 2% by mass or more and 40% by mass or less, based on the total amount of the thermosetting component and the elastomer component.

The sealing film according to the present embodiment can be suitably used for a hollow structure including a substrate, a sealed body (for example, an electronic component such as a SAW device) provided on the substrate, and a hollow region provided between the substrate and the sealed body. According to the sealing film, the sealing material can be sufficiently prevented from flowing into the hollow region between the substrate and the sealed body. Further, according to the sealing film, since a cured product having a sufficient glass transition temperature can be formed, a sealed structure having excellent reliability (thermal reliability) can be obtained. The reason why such an effect can be obtained is not clear, but the present inventors presume as follows.

That is, first, when the carboxyl equivalent of the elastomer is less than 270g/eq, the polarity of the elastomer becomes large, and therefore, it is presumed that the molecular chain of the elastomer forms a coiled structure in the sealing film (in the resin composition). As described above, when the elastomer is excessively wound, the resistance effect of suppressing the fluidity of the resin composition in the sealing film is considered to be small. Therefore, it is presumed that a large amount of an elastomer component needs to be added in order to sufficiently suppress the flow of the sealing material into the hollow region. On the other hand, when the carboxyl equivalent is more than 4300g/eq, the polarity of the elastomer is small, and therefore, although it is estimated that the molecular chain of the elastomer forms a nearly linear structure in the sealing film (in the resin composition), the interaction between the molecular chains is small because the number of carboxyl groups as polar groups is small. In this case, since the interaction between the molecular chains is small, it is considered that only an effect corresponding to the amount of the elastomer component added is obtained as an effect of suppressing the fluidity of the resin composition in the sealing film obtained by adding the elastomer component. In contrast, the sealing film of the present embodiment contains an elastomer having a carboxyl equivalent weight of 270 to 4300g/eq. Presume that: the elastomer maintains a linear shape in the resin composition, and molecular chains of the elastomer are artificially polymerized by the interaction of carboxyl groups (that is, the molecular chains of the elastomer form a three-dimensional network). Therefore, the amount of the elastomer component added to the sealing film can be made smaller than in the conventional art, and as a result, the above-described effects are presumed to be obtained.

When the sealing film contains an elastomer component at a high concentration, it is estimated that the amount of thermal expansion changes more when the electronic component device is mounted due to the influence of Tg derived from the elastomer component in a low temperature region, and defects (warpage, cracks, and the like) are likely to occur. In contrast, in the sealing film of the present embodiment, since the content of the elastomer component is in the above range, the number of mounting defects can be reduced.

In addition, when the sealing film contains an elastomer component at a high concentration, sufficient embedding properties for the sealed body may not be obtained. In contrast, in the sealing film of the present embodiment, since the amount of the elastomer component added can be reduced, sufficient embedding properties with respect to the sealed body can be easily obtained.

(thermosetting component)

Examples of the thermosetting component include thermosetting resins, curing agents, and curing accelerators. The thermosetting component may contain a thermosetting resin without containing a curing agent and/or a curing accelerator.

[ thermosetting resin ]

Examples of the thermosetting resin include epoxy resins, phenoxy resins, cyanate ester resins, thermosetting polyimides, melamine resins, urea resins, unsaturated polyesters, alkyd resins, and polyurethanes. As the thermosetting resin, an epoxy resin is preferable from the viewpoint of easiness in controlling the fluidity and curing reactivity of the resin.

The epoxy resin is not particularly limited as long as it has 2 or more epoxy groups in one molecule. Examples of the epoxy resin include: bisphenol A type epoxy resin, bisphenol AP type epoxy resin, bisphenol AF type epoxy resin, bisphenol B type epoxy resin, bisphenol BP type epoxy resin, bisphenol C type epoxy resin, bisphenol E type epoxy resin, bisphenol F type epoxy resin, bisphenol G type epoxy resin, bisphenol M type epoxy resin, bisphenol S type epoxy resin (hexanediol bisphenol S diglycidyl ether, etc.), bisphenol P-type epoxy resins, bisphenol PH-type epoxy resins, bisphenol TMC-type epoxy resins, bisphenol Z-type epoxy resins, phenol novolac-type epoxy resins, biphenyl-type epoxy resins, naphthalene-type epoxy resins, dicyclopentadiene-type epoxy resins, biphenol-type epoxy resins (such as biscresol diglycidyl ether), hydrogenated bisphenol a-type epoxy resins (such as hydrogenated bisphenol a glycidyl ether), and dibasic acid-modified diglycidyl ether-type epoxy resins of these resins; aliphatic epoxy resins, and the like. One kind of the epoxy resin may be used alone, or two or more kinds may be used in combination.

The epoxy resin may be an epoxy resin that is liquid at 25 ℃ (liquid epoxy resin) from the viewpoint of easily suppressing the occurrence of cracks and fissures on the film surface. As the liquid epoxy resin, there can be mentioned: bisphenol a type glycidyl ether, bisphenol AD type glycidyl ether, bisphenol S type glycidyl ether, bisphenol F type glycidyl ether, hydrogenated bisphenol a type glycidyl ether, ethylene oxide adduct bisphenol a type glycidyl ether, propylene oxide adduct bisphenol a type glycidyl ether, naphthalene resin glycidyl ether, 3-functional or 4-functional glycidyl amine, and the like. The phrase "in a liquid state at 25 ℃ means that the viscosity at 25 ℃ as measured with an E-type viscometer is 400 pas or less.

Examples of commercially available epoxy resins include: a soft and tough epoxy resin such as "jER 825" (bisphenol a type epoxy resin, epoxy equivalent: 175g/eq.) manufactured by mitsubishi chemical corporation, a "jER 806" (bisphenol F type epoxy resin, epoxy equivalent: 160g/eq.) manufactured by mitsubishi chemical corporation, a "HP-4032D" (naphthalene type epoxy resin, epoxy equivalent: 141g/eq.) manufactured by DIC corporation, and a "EXA-4850" manufactured by DIC corporation; a trade name "HP-4700" (4-functional naphthalene type epoxy resin), a trade name "HP-4750" (3-functional naphthalene type epoxy resin), a trade name "HP-4710" (4-functional naphthalene type epoxy resin), a trade name "EPICLON-770" (phenol novolac type epoxy resin), a trade name "EPICLON-660" (cresol novolac type epoxy resin), and a trade name "EPICLON HP-7200H" (dicyclopentadiene type epoxy resin), manufactured by DIC corporation; trade name "EPPN-502H" (triphenylmethane type epoxy resin) and trade name "NC-3000" (biphenyl aralkyl type epoxy resin) manufactured by Nippon chemical Co., Ltd.; a trade name "ESN-355" (naphthalene type epoxy resin) manufactured by Nippon iron Japan chemical Co., Ltd.; trade name "YX-8800" (anthracene-type epoxy resin) manufactured by Mitsubishi chemical corporation, trade name "ESCN-190-2" (o-cresol novolac-type epoxy resin) manufactured by Sumitomo chemical corporation, and the like. These epoxy resins may be used alone or in combination of two or more.

From the viewpoint of easily obtaining excellent fluidity, the content of the thermosetting resin is preferably not less than 1% by mass, more preferably not less than 3% by mass, further preferably not less than 4% by mass, particularly preferably not less than 5% by mass, very preferably not less than 10% by mass, and very preferably not less than 15% by mass, based on the total mass of the sealing film. From the viewpoint of easily suppressing the occurrence of cracks and fissures on the film surface, the content of the thermosetting resin is preferably 30% by mass or less, more preferably 25% by mass or less, and still more preferably 20% by mass or less, based on the total mass of the sealing film. The upper limit value and the lower limit value may be arbitrarily combined. Therefore, the content of the thermosetting resin may be, for example, 1 to 30% by mass, 3 to 30% by mass, 4 to 25% by mass, 5 to 25% by mass, 10 to 20% by mass, or 15 to 20% by mass based on the total mass of the sealing film. In the following description, the upper limit value and the lower limit value described in the respective descriptions may be arbitrarily combined.

In the case where the resin composition is an epoxy resin composition containing an epoxy resin, the content of the epoxy resin is preferably 50% by mass or more, more preferably 80% by mass or more, and further preferably 90% by mass or more, based on the total mass of the thermosetting resin, from the viewpoint of easily obtaining a cured product having excellent thermal conductivity. The content of the epoxy resin may be 100% by mass based on the total mass of the thermosetting resin.

From the viewpoint of easily suppressing the occurrence of cracks and fissures on the film surface, the content of the liquid epoxy resin is preferably not less than 0.5% by mass, more preferably not less than 1% by mass, still more preferably not less than 3% by mass, particularly preferably not less than 5% by mass, very preferably not less than 7% by mass, and very preferably not less than 9% by mass, based on the total mass of the sealing film. From the viewpoint of easily suppressing excessive increase in the viscosity of the film and the viewpoint of easily suppressing edge fusion, the content of the liquid epoxy resin is preferably 20% by mass or less, more preferably 15% by mass or less, and still more preferably 13% by mass or less, based on the total mass of the sealing film. Therefore, the content of the liquid epoxy resin may be, for example, 0.5 to 20% by mass, 1 to 20% by mass, 3 to 15% by mass, 5 to 15% by mass, 7 to 13% by mass, or 9 to 13% by mass based on the total mass of the sealing film.

From the viewpoint of easily suppressing the occurrence of cracks and fissures on the film surface, the content of the liquid epoxy resin is preferably not less than 20 mass%, more preferably not less than 30 mass%, and still more preferably not less than 50 mass%, based on the total mass of the thermosetting resin. From the viewpoint of easily suppressing excessive increase in the viscosity of the film and the viewpoint of easily suppressing edge fusion, the content of the liquid epoxy resin is preferably 95% by mass or less, more preferably 90% by mass or less, and still more preferably 80% by mass or less, based on the total mass of the thermosetting resin. Therefore, the content of the liquid epoxy resin may be, for example, 20 to 95% by mass, 30 to 90% by mass, or 50 to 80% by mass based on the total mass of the thermosetting resin. The content of the liquid epoxy resin may be 100% by mass based on the total mass of the thermosetting resin.

[ curing agent ]

The curing agent is not particularly limited, and examples thereof include a phenol-based curing agent (e.g., a phenol resin), an acid anhydride-based curing agent, an active ester-based curing agent, and a cyanate ester-based curing agent. When the thermosetting resin contains an epoxy resin, the curing agent is not particularly limited as long as it is a compound having 2 or more functional groups reactive with an epoxy group in one molecule. Examples of such a curing agent include phenolic resins and acid anhydrides. As the curing agent, a phenol resin is preferable from the viewpoint of easily obtaining a cured product having excellent thermal conductivity. One curing agent may be used alone, or two or more curing agents may be used in combination.

As the phenol resin, a known phenol resin can be used without particular limitation as long as it has 2 or more phenolic hydroxyl groups in one molecule. Examples of the phenolic resin include: resins obtained by condensation or co-condensation of phenols and/or naphthols and aldehydes under an acidic catalyst, biphenyl skeleton-type phenol resins, p-xylene-modified phenol resins, m-xylene/p-xylene-modified phenol resins, melamine-modified phenol resins, terpene-modified phenol resins, dicyclopentadiene-modified phenol resins, cyclopentadiene-modified phenol resins, polycyclic aromatic ring-modified phenol resins, xylene-modified naphthol resins, and the like. Examples of the phenol include phenol, cresol, xylenol, resorcinol, catechol, bisphenol a, and bisphenol F. Examples of the naphthol include α -naphthol, β -naphthol, and dihydroxynaphthalene. Examples of the aldehydes include formaldehyde, acetaldehyde, propionaldehyde, benzaldehyde, and salicylaldehyde.

Examples of commercially available phenol resins include: the trade name "PAPS-PN 2" (Novolac type phenol resin) manufactured by Asahi organic materials industries Co., Ltd; trade name "SK Resin HE 200C-7" (biphenyl aralkyl type phenol Resin) and trade name "HE 910-10" (triphenylmethane type phenol Resin) manufactured by AIR WATER; trade names "MEH-7000", "DL-92", "H-4" and "HF-1M" manufactured by Minghe Kabushiki Kaisha; trade names "LVR-8210 DL", "ELP" series and "NC" series available from Rongchen chemical industries, Ltd; trade names "SN-100, SN-300, SN-395, SN-400" (naphthalene type phenol resin) manufactured by Nissian iron-on-gold chemical Co., Ltd.; and a trade name "HP-850N" (novolak phenol resin) manufactured by Hitachi chemical Co., Ltd.

From the viewpoint of excellent curability of the thermosetting resin, the content of the curing agent may be 1 to 20% by mass, 2 to 15% by mass, or 3 to 10% by mass based on the total mass of the sealing film.

When the thermosetting resin contains an epoxy resin, the ratio (M1/M2) of the number of moles M1 of epoxy groups of the epoxy resin to the number of moles M2 (phenolic hydroxyl group equivalent or the like) of functional groups (phenolic hydroxyl group or the like) in the curing agent that react with epoxy groups may be greater than or equal to 0.7, greater than or equal to 0.8, or greater than or equal to 0.9, and in addition, may be less than or equal to 2.0, less than or equal to 1.8, or less than or equal to 1.7. The ratio (M1/M2) is preferably 0.7 to 2.0, more preferably 0.8 to 1.8, and still more preferably 0.9 to 1.7. When the ratio is 0.7 or more and 2.0 or less, unreacted epoxy resin and/or unreacted curing agent are less likely to remain, and desired cured product characteristics are more likely to be obtained.

[ curing accelerators ]

The curing accelerator may be used without particular limitation, and is preferably at least one selected from the group consisting of amine-based curing accelerators and phosphorus-based curing accelerators. The curing accelerator is preferably an amine-based curing accelerator, more preferably at least one selected from the group consisting of imidazole compounds, aliphatic amines and alicyclic amines, and even more preferably an imidazole compound, from the viewpoint of easily obtaining a cured product having excellent thermal conductivity, from the viewpoint of abundance of derivatives, and from the viewpoint of easily obtaining a desired active temperature. Examples of the imidazole compound include 2-phenyl-4-methylimidazole and 1-benzyl-2-methylimidazole. The curing accelerator may be used alone or in combination of two or more. Commercially available products of the curing accelerator include "2P 4 MZ" and "1B 2 MZ" manufactured by national chemical industries co.

The content of the curing accelerator is preferably in the following range based on the thermosetting resin (epoxy resin, etc.) and the curing agent (phenol resin, etc.). The content of the curing accelerator is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, and still more preferably 0.3% by mass or more, from the viewpoint of easily obtaining a sufficient curing accelerating effect. The content of the curing accelerator is preferably 5% by mass or less, more preferably 3% by mass or less, and still more preferably 1.5% by mass or less, from the viewpoint that curing is not easily performed in the steps (for example, coating and drying) in the production of the sealing film or in the storage of the sealing film, and cracking of the sealing film and molding defects associated with an increase in melt viscosity are easily prevented. From these viewpoints, the content of the curing accelerator is preferably 0.01 to 5% by mass, more preferably 0.1 to 3% by mass, and still more preferably 0.3 to 1.5% by mass.

(inorganic Filler)

The inorganic filler is not particularly limited, and conventionally known inorganic fillers can be used. Examples of the constituent material of the inorganic filler include: silica (amorphous silica, crystalline silica, fused silica, spherical silica, synthetic silica, hollow silica, etc.), barium sulfate, barium titanate, talc, clay, mica powder, magnesium carbonate, calcium carbonate, alumina (aluminum oxide), aluminum hydroxide, magnesium oxide, magnesium hydroxide, silicon nitride, aluminum borate, boron nitride, barium titanate, strontium titanate, calcium titanate, magnesium titanate, bismuth titanate, titanium oxide, barium zirconate, calcium zirconate, etc. The inorganic filler containing silica is preferable from the viewpoint of easily obtaining the effect of improving dispersibility in the resin composition and the effect of suppressing sedimentation in the varnish by surface modification (for example, surface treatment with a silane compound) or the like, and from the viewpoint of easily obtaining desired cured film characteristics because of having a small thermal expansion coefficient. From the viewpoint of obtaining high thermal conductivity, an inorganic filler containing alumina is preferable. One kind of the inorganic filler may be used alone, or two or more kinds may be used in combination.

The inorganic filler may be surface-modified. The method of surface modification is not particularly limited. Surface modification using a silane coupling agent is preferable from the viewpoint of easy handling, abundant functional group types, and easiness of imparting desired characteristics.

examples of the silane coupling agent include: alkylsilanes, alkoxysilanes, vinylsilanes, epoxysilanes, aminosilanes, acrylic silanes, methacrylic silanes, mercaptosilanes, thioether silanes, isocyanate silanes, sulfur silanes, styrylsilanes, alkylchlorosilanes, and the like.

Specific examples of the silane coupling agent include: methyltrimethoxysilane, dimethyldimethoxysilane, trimethylmethoxysilane, methyltriethoxysilane, methyltriphenoxysilane, ethyltrimethoxysilane, n-propyltrimethoxysilane, diisopropyldimethoxysilane, isobutyltrimethoxysilane, diisobutyldimethoxysilane, isobutyltriethoxysilane, n-hexyltrimethoxysilane, n-hexyltriethoxysilane, cyclohexylmethyldimethoxysilane, n-octyltriethoxysilane, n-dodecylmethoxysilane, phenyltrimethoxysilane, diphenyldimethoxysilane, triphenylsilanol, methyltrichlorosilane, dimethyldichlorosilane, trimethylchlorosilane, n-octyldimethylchlorosilane, tetraethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3- (2-aminoethyl) aminopropyltrimethoxysilane, 3- (2-aminoethyl) aminopropylmethyldimethoxysilane, 3-phenylaminopropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, bis (3- (triethoxysilyl) propyl) disulfide, bis (3- (triethoxysilyl) propyl) tetrasulfide, vinyltriacetoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriisopropoxysilane, allyltrimethoxysilane, diallyldimethylsilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, glycidylmethoxysilane, glycidylmethane, 3-methacryloxypropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltriethoxysilane, N- (1, 3-dimethylbutylidene) -3-aminopropyltriethoxysilane, aminosilanes (such as phenylaminosilane) and the like. One kind of silane coupling agent may be used alone, or two or more kinds may be used in combination.

From the viewpoint of easily suppressing aggregation of the inorganic filler and easily dispersing the inorganic filler, the average particle diameter of the inorganic filler is preferably not less than 0.01. mu.m, more preferably not less than 0.1. mu.m, still more preferably not less than 0.3. mu.m, and particularly preferably not less than 0.5. mu.m. From the viewpoint of easily suppressing the sedimentation of the inorganic filler in the varnish and easily producing a homogeneous sealing film, the average particle diameter of the inorganic filler is preferably 25 μm or less, more preferably 10 μm or less, and still more preferably 5 μm or less. From these viewpoints, the average particle diameter of the inorganic filler is preferably 0.01 to 25 μm, more preferably 0.01 to 10 μm, still more preferably 0.1 to 10 μm, particularly preferably 0.3 to 5 μm, and most preferably 0.5 to 5 μm. The inorganic filler may have an average particle diameter of 10 to 18 μm.

From the viewpoint of excellent flowability of the resin composition, it is preferable to use a combination of a plurality of inorganic fillers having different average particle diameters. In the combination of the inorganic fillers, the maximum average particle diameter is preferably 15 to 25 μm. Preferably, an inorganic filler having an average particle diameter of 15 to 25 μm, an inorganic filler having an average particle diameter of 0.5 to 2.5 μm and an inorganic filler having an average particle diameter of 0.1 to 1.0 μm are used in combination.

The "average particle diameter" is a particle diameter at a point corresponding to 50% by volume when a cumulative particle size distribution curve based on the particle diameter is obtained with the total volume of the particles being 100%, and can be measured by a particle size distribution measuring apparatus using a laser diffraction scattering method or the like. The average particle diameter of each inorganic filler to be combined can be confirmed from the average particle diameter of each inorganic filler at the time of mixing, and can be confirmed by measuring the particle size distribution.

Commercially available inorganic fillers include "DAW-20" manufactured by Denka corporation, "SC 5500-SXE" and "SC 2050-KC" manufactured by Admatechs corporation.

The content of the inorganic filler may be 70% by mass or more, 75% by mass or more, 80% by mass or more, or 84% by mass or more based on the total mass of the sealing film, from the viewpoint of improving the thermal conductivity and easily suppressing the increase in warpage of the sealing structure (for example, an electronic component device such as a semiconductor device) due to the difference in thermal expansion coefficient from the sealed body. The content of the inorganic filler may be 93% by mass or less, may be 91% by mass or less, may be 90% by mass or less, or may be 88% by mass or less, based on the total mass of the sealing film, from the viewpoint of easily suppressing cracking of the sealing film in a drying step when the sealing film is produced, suppressing a decrease in fluidity of the sealing film due to an increase in melt viscosity, and easily sealing a sealed body (electronic component or the like). From these viewpoints, the content of the inorganic filler may be 70 to 93% by mass, 75 to 91% by mass, 80 to 90% by mass, or 84 to 88% by mass based on the total mass of the sealing film. The content is the content of the inorganic filler excluding the amount of the surface treatment agent.

(Elastomers)

the elastomer component comprises a carboxyl group-containing elastomer having a carboxyl group equivalent of 270 to 4300g/eq. Here, the "carboxyl equivalent" refers to the mass of the carboxyl group-containing elastomer with 1 equivalent (1eq.) of carboxyl groups in the carboxyl group-containing elastomer. The carboxyl equivalent can be determined from the amount of the monomer component charged. The carboxyl equivalent can be measured by titration.

From the viewpoint of suppressing the elastomer from becoming excessively curled and easily obtaining the fluidity-suppressing effect of the resin composition, the carboxyl group equivalent of the carboxyl group-containing elastomer may be not less than 340g/eq, not less than 400g/eq, not less than 600g/eq, or not less than 800g/eq. The carboxyl equivalent weight of the carboxyl group-containing elastomer may be 4000g/eq or less, may be 3000g/eq or less, or may be 2000g/eq or less, from the viewpoint that the molecular chains of the elastomer easily form a more compact three-dimensional network with each other and the hollow non-fillability becomes better. From these viewpoints, the carboxyl equivalent of the carboxyl group-containing elastomer may be 340 to 4000g/eq, 400 to 4000g/eq, 600 to 3000g/eq, or 800 to 2000g/eq.

The carboxyl group-containing elastomer preferably contains a structural unit derived from (meth) acrylic acid represented by the following formula (1) as a structural unit having a carboxyl group.

[ solution 1]

[ in the formula (1), R1 represents a hydrogen atom or a methyl group. ]

From the viewpoint of suppressing the elastomer from becoming excessively curled and easily obtaining the effect of suppressing the fluidity of the resin composition, the content of the structural unit having a carboxyl group in the carboxyl group-containing elastomer may be 2 mol% or more, 4 mol% or more, or 6 mol% or more, based on the total amount of the structural units constituting the carboxyl group-containing elastomer. The content of the structural unit having a carboxyl group may be 39 mol% or less, 37 mol% or less, 35 mol% or less, 31 mol% or less, or 29 mol% or less based on the total amount of the structural units constituting the carboxyl group-containing elastomer, from the viewpoint that the molecular chains of the elastomer easily form a more compact three-dimensional network with each other and the hollow non-fillability becomes better. From these viewpoints, the content of the structural unit having a carboxyl group may be 2 to 35 mol%, 4 to 31 mol%, or 6 to 29 mol%. From the same viewpoint, the content of the structural unit represented by the above formula (1) may be in the above range.

The carboxyl group-containing elastomer may be a copolymer (for example, a random copolymer, a block copolymer, or the like) composed of a plurality of different structural units. The carboxyl group-containing elastomer may further have a structural unit other than the structural unit having a carboxyl group. Examples of the other structural units include structural units having an carbalkoxy group (-C (═ O) -O-R (R represents an alkyl group which may have a substituent), a nitrile group (-C ≡ N), a hydroxyl group (-OH), an allyl group, and the like. Examples of R in the carbalkoxy group include a methyl group, an ethyl group, and a butyl group. The carboxyl group-containing elastomer is preferably a copolymer of (meth) acrylic acid with another monomer ((meth) acrylic acid copolymer).

Examples of the structural unit having an alkyl ester group include structural units derived from an alkyl (meth) acrylate represented by the following formula (2). That is, the carboxyl group-containing elastomer may be a copolymer of a monomer having a carboxyl group and an alkyl (meth) acrylate (carboxyl group-containing alkyl (meth) acrylate copolymer), and is preferably a copolymer of (meth) acrylic acid and (meth) acrylic acid ester ((meth) acrylic acid-alkyl (meth) acrylate copolymer).

[ solution 2]

[ in the formula (2), R2 represents a hydrogen atom or a methyl group, and R represents an alkyl group which may have a substituent. ]

The content of the structural unit represented by the above formula (2) in the carboxyl group-containing elastomer may be 65 mol% or more, 69 mol% or more, or 71 mol% or more, and may be 98 mol% or less, 96 mol% or less, or 94 mol% or less, based on the total amount of the structural units constituting the carboxyl group-containing elastomer, from the viewpoint of further excellent hollow non-fillability and easy attainment of a more sufficient Tg after curing. Therefore, the content of the structural unit represented by the above formula (2) may be, for example, 65 to 98 mol%, 69 to 96 mol%, or 71 to 94 mol%, based on the total amount of the structural units constituting the carboxyl group-containing elastomer.

Examples of the structural unit having a nitrile group include a structural unit derived from (meth) acrylonitrile represented by the following formula (3).

[ solution 3]

[ in formula (3), R3 represents a hydrogen atom or a methyl group. ]

The content of the structural unit represented by the above formula (3) in the carboxyl group-containing elastomer may be 65 to 98 mol%, 69 to 96 mol%, or 71 to 94 mol%, based on the total amount of the structural units constituting the carboxyl group-containing elastomer, from the viewpoint of further excellent hollow non-fillability and easy achievement of a more sufficient Tg after curing.

From the viewpoint of further excellent hollow non-fillability and easy obtainment of a more sufficient Tg after curing, the carboxyl group-containing elastomer preferably has a structural unit represented by the above formula (1), and a structural unit represented by the above formula (2) and/or a structural unit represented by the above formula (3).

The weight average molecular weight Mw of the carboxyl group-containing elastomer may be 30 ten thousand or more, 40 ten thousand or more, or 50 ten thousand or more, or 1000 ten thousand or less, 800 ten thousand or less, or 700 ten thousand or less, or 200 ten thousand or less, from the viewpoint of more excellent hollow non-filling property, more easily obtaining a more sufficient Tg after curing, and being able to obtain a sufficient embedding property for the sealed body. Accordingly, the weight average molecular weight Mw of the carboxyl group-containing elastomer may be, for example, 30 to 1000 ten thousand, 40 to 800 ten thousand, 50 to 700 ten thousand, or 50 to 200 ten thousand. The weight average molecular weight is a polystyrene conversion value obtained by Gel Permeation Chromatography (GPC) using a standard curve based on standard polystyrene.

When the carboxyl group-containing elastomer is in the form of particles, the average particle diameter of the elastomer is not particularly limited. The average particle diameter of the elastomer may be, for example, 50 μm or less from the viewpoint of excellent embedding property between the sealed bodies. The average particle diameter of the elastomer may be 0.1 μm or more from the viewpoint of excellent dispersibility of the carboxyl group-containing elastomer.

The carboxyl group-containing elastomer of the present embodiment can be obtained by polymerizing a polymerizable monomer having a carboxyl group by a conventionally known method, or can be obtained by copolymerizing a polymerizable monomer having a carboxyl group and a polymerizable monomer having no carboxyl group by a conventionally known method. For example, the carboxyl group-containing elastomer can be obtained by copolymerizing (meth) acrylic acid with an alkyl (meth) acrylate and/or (meth) acrylonitrile. In the present embodiment, the carboxyl equivalent weight can be adjusted to a desired range by adjusting the amount of the polymerizable monomer used. In the present embodiment, after the polymer is obtained by the above-described method, the carboxyl equivalent weight can be adjusted by substituting a part of the carboxyl groups by a method such as esterification.

In the polymerization, a polymerization initiator may be used. As the polymerization initiator, a thermal radical polymerization initiator, a photo radical polymerization initiator, an anionic polymerization initiator and a cationic polymerization initiator can be cited.

The content of the carboxyl group-containing elastomer may be less than 40% by mass based on the total amount of the thermosetting component and the carboxyl group-containing elastomer. In the present embodiment, by setting the content of the elastomer component to the above range, the sealing film has a sufficient Tg after curing, and a sealed structure having excellent reliability can be obtained. From the viewpoint of better hollow non-fillability, the content of the carboxyl group-containing elastomer may be more than 0% by mass, may be 2% by mass or more, may be 4% by mass or more, may be 8% by mass or more, and may be 12% by mass or more, based on the total amount of the thermosetting component and the carboxyl group-containing elastomer. The content of the carboxyl group-containing elastomer may be 35% by mass or less, 30% by mass or less, or 25% by mass or less based on the total amount of the thermosetting component and the carboxyl group-containing elastomer, from the viewpoint of making Tg after curing more sufficient and from the viewpoint of obtaining sufficient embedding properties with respect to the sealed body. Therefore, the content of the carboxyl group-containing elastomer may be, for example, more than 0% by mass and less than 40% by mass, or more than or equal to 2% by mass and less than 40% by mass, or 4 to 35% by mass, or 8 to 30% by mass, or 12 to 25% by mass, based on the total amount of the thermosetting component and the carboxyl group-containing elastomer.

In the present embodiment, the total amount of the thermosetting component, the inorganic filler and the carboxyl group-containing elastomer in the sealing film may be 80% by mass or more, 90% by mass or more, 95% by mass or more, or 100% by mass based on the total mass of the sealing film.

The elastomer component (for example, a carboxyl group-containing elastomer) is a thermoplastic resin, the glass transition temperature (Tg) of the elastomer component as measured by a dynamic viscoelasticity measuring apparatus is preferably 20 ℃ or less, and the elastic modulus of the elastomer component at 25 ℃ as measured by a dynamic viscoelasticity measuring apparatus is preferably 5MPa or less.

The sealing film of the present embodiment may contain an elastomer other than the above-described carboxyl group-containing elastomer within a range that does not affect the effects of the present invention. Examples of the other elastomer include polybutadiene particles, styrene-butadiene particles, acrylic elastomers, silicone powder, silicone oil, and silicone oligomer.

In the sealing film of the present embodiment, the content of the elastomer component (including the carboxyl group-containing elastomer) is preferably 2% by mass or more and 40% by mass or less based on the total amount of the thermosetting component and the elastomer component. That is, even in the case where the elastomer component contains an elastomer other than the carboxyl group-containing elastomer, the total amount of the elastomer component is preferably 2% by mass or more and less than 40% by mass based on the total amount of the thermosetting component and the elastomer component. In this case, the sealing film has a more sufficient Tg after curing, and a sealed structure having more excellent reliability can be obtained. From the viewpoint of better hollow non-fillability, the content of the elastomer component may be 4% by mass or more, 8% by mass or more, or 12% by mass or more, based on the total amount of the thermosetting component and the elastomer component. From the viewpoint of making Tg after curing more sufficient and from the viewpoint of obtaining sufficient embedding properties with respect to the sealed body, the content of the elastomer component may be 35% by mass or less, 30% by mass or less, or 25% by mass or less, based on the total amount of the thermosetting component and the elastomer component. Therefore, the content of the elastomer component may be, for example, 4 to 35% by mass, 8 to 30% by mass, or 12 to 25% by mass based on the total amount of the thermosetting component and the elastomer component.

The content of the carboxyl group-containing elastomer in the elastomer component may be 80% by mass or more, 90% by mass or more, or 95% by mass or more, based on the total mass of the elastomer component, from the viewpoint of better hollow non-fillability. The content of the carboxyl group-containing elastomer in the elastomer component may be 100% by mass or less. Therefore, the content of the carboxyl group-containing elastomer in the elastomer component may be, for example, 80 to 100% by mass based on the total mass of the elastomer component. The elastomer component may substantially contain only the carboxyl group-containing elastomer.

(other Components)

The sealing film of the present embodiment may further contain other additives. Specific examples of such additives include: pigments, dyes, mold release agents, antioxidants, surface tension modifiers, and the like.

The sealing film of the present embodiment may contain a solvent (for example, a solvent used for producing the sealing film). The solvent may be a conventionally known organic solvent. The organic solvent may be a solvent capable of dissolving components other than the inorganic filler, and examples thereof include aliphatic hydrocarbons, aromatic hydrocarbons, terpenes, halogens, esters, ketones, alcohols, and aldehydes. One solvent may be used alone, or two or more solvents may be used in combination.

The solvent may be at least one selected from the group consisting of esters, ketones, and alcohols, from the viewpoint of reducing environmental load and from the viewpoint of easily dissolving the thermosetting component. Among them, when the solvent is a ketone, the thermosetting component is particularly easily dissolved. The solvent may be at least one selected from the group consisting of acetone, methyl ethyl ketone and methyl isobutyl ketone, from the viewpoint of less volatilization at room temperature (25 ℃) and easy removal at the time of drying.

The content of the solvent (organic solvent or the like) contained in the sealing film is preferably in the following range based on the total mass of the sealing film. The content of the solvent may be 0.2% by mass or more, 0.3% by mass or more, 0.5% by mass or more, 0.6% by mass or more, or 0.7% by mass or more, from the viewpoints of easily suppressing the sealing film from becoming brittle and causing defects such as cracking of the sealing film, and easily suppressing the decrease in embedding property due to the increase in the minimum melt viscosity. The content of the solvent may be 1.5% by mass or less, or 1% by mass or less, from the viewpoints of easily suppressing a problem such as deterioration of workability due to excessively strong adhesiveness of the sealing film and easily suppressing a problem such as foaming accompanied by volatilization of the solvent (organic solvent or the like) during thermal curing of the sealing film. From these viewpoints, the content of the solvent may be 0.2 to 1.5% by mass, 0.3 to 1% by mass, 0.5 to 1% by mass, 0.6 to 1% by mass, or 0.7 to 1% by mass.

The thickness (film thickness) of the sealing film may be 20 μm or more, 30 μm or more, 50 μm or more, or 100 μm or more, from the viewpoint of easily suppressing variation in-plane thickness at the time of coating. The thickness of the sealing film may be 400 μm or less, 250 μm or less, 200 μm or less, or 150 μm or less, from the viewpoint of easily obtaining a certain drying property in the depth direction at the time of coating. From these viewpoints, the thickness of the sealing film may be 20 to 400 μm, 20 to 250 μm, 30 to 250 μm, 50 to 200 μm, or 100 to 150 μm. Further, a plurality of sealing films may be laminated to produce a sealing film having a thickness of more than 250 μm.

From the viewpoint of reliability (thermal reliability) of the obtained sealing structure, the glass transition temperature Tg of the sealing film after curing may be 80 to 150 ℃, 90 to 140 ℃, or 100 to 130 ℃. The glass transition temperature Tg of the sealing film can be adjusted by the type and content of the thermosetting component, the type and content of the elastomer component, and the like. The glass transition temperature Tg can be determined by the method described in the examples.

From the viewpoint of forming a hollow structure, the minimum value of the melt viscosity (minimum melt viscosity) of the sealing film at 60 to 140 ℃ may be 1000 to 20000Pa · s, 3000 to 15000Pa · s, or 5000 to 12000Pa · s. The minimum melt viscosity can be determined by measuring the melt viscosity of the sealing film by the method described in examples.

As described above, the sealing film of the present embodiment can be suitably used for sealing a sealed body in a hollow structure, but the structure to be sealed may not have a hollow structure. The sealing film of the present embodiment can also be used for sealing a semiconductor device, embedding an electronic component disposed in a printed wiring board, and the like.

The sealing film of the present embodiment may be used as a sealing film with a support, for example. The sealing film 10 with a support shown in fig. 1 includes a support 1 and a sealing film 2 provided on the support 1.

As the support 1, a polymer film, a metal foil, or the like can be used. Examples of the polymer film include: polyolefin films such as polyethylene films and polypropylene films; vinyl films such as polyvinyl chloride films; polyester films such as polyethylene terephthalate films; a polycarbonate film; a cellulose acetate film; tetrafluoroethylene membranes, and the like. Examples of the metal foil include copper foil and aluminum foil.

The thickness of the support 1 is not particularly limited, and may be 2 to 200 μm from the viewpoint of excellent workability and drying property. When the thickness of the support 1 is 2 μm or more, the trouble of breaking the support at the time of coating, the trouble of bending the support due to the weight of the varnish, and the like are easily suppressed. When the thickness of the support 1 is 200 μm or less, when hot air is blown from both the coated surface and the back surface in the drying step, the problem that drying of the solvent in the varnish is hindered is easily suppressed.

In the present embodiment, the support 1 may not be used. Further, a protective layer for the purpose of protecting the sealing film may be disposed on the side of the sealing film 2 opposite to the support 1. By forming the protective layer on the sealing film 2, the workability can be improved, and troubles such as adhesion of the sealing film to the back surface of the support body during winding can be avoided.

As the protective layer, a polymer film, a metal foil, or the like can be used. Examples of the polymer film include: polyolefin films such as polyethylene films and polypropylene films; vinyl films such as polyvinyl chloride films; polyester films such as polyethylene terephthalate films; a polycarbonate film; a cellulose acetate film; tetrafluoroethylene membranes, and the like. Examples of the metal foil include copper foil and aluminum foil.

< method for producing sealing film >

The sealing film of the present embodiment can be produced specifically as follows.

First, the constituent components of the resin composition of the present embodiment (thermosetting resin, curing agent, curing accelerator, inorganic filler, elastomer component, solvent, and the like) are mixed to prepare a varnish (varnish-like resin composition). The mixing method is not particularly limited, and a mill, a mixer, and a stirring blade may be used. The solvent (such as an organic solvent) can be used for dissolving and dispersing the components of the resin composition as the sealing film material to prepare a varnish or for preparing a varnish as an auxiliary. Most of the solvent can be removed by a drying step after coating.

The varnish prepared in this way is applied to a support (e.g., a film-shaped support), and then heated and dried by blowing hot air or the like, thereby producing a sealing film. The coating method is not particularly limited, and for example, a coater such as a die coater, a gravure coater, a kiss coater, a roll coater, a bar coater, a kiss coater, or the like may be used.

< sealing Structure and method for producing same >

The seal structure according to the present embodiment includes a sealed body and a seal portion that seals the sealed body. The sealing portion is a cured product of the sealing film of the present embodiment, and includes a cured product of the resin composition of the present embodiment. The seal structure may be a hollow seal structure having a hollow structure. The hollow seal structure includes, for example, a substrate, a sealed body provided on the substrate, a hollow region provided between the substrate and the sealed body, and a seal portion for sealing the sealed body. The seal structure of the present embodiment may include a plurality of sealed bodies. The plurality of sealed bodies may be of the same type or different types.

The sealing structure is, for example, an electronic component device. The electronic component device includes an electronic component as a sealed body. Examples of the electronic component include: a semiconductor element; a semiconductor wafer; an integrated circuit; a semiconductor device; filters such as SAW filters; passive components such as sensors, etc. A semiconductor element obtained by singulating a semiconductor wafer may be used. The electronic component device may be a semiconductor device including a semiconductor element or a semiconductor wafer as an electronic component; printed wiring boards, and the like. When the electronic component device has a hollow structure, that is, when the electronic component device is a hollow sealed structure, the sealed body is provided on the substrate via a bump so as to have a movable portion on the surface on the hollow region side (substrate side), for example. Examples of the sealed body include SAW devices such as SAW filters, and electronic components such as acceleration sensors. When the sealed body is a SAW filter, a movable portion is formed on a surface of the piezoelectric substrate on which a pair of IDTs (Inter Digital transducers) as comb-shaped electrodes are mounted.

Next, a method for producing a hollow sealed structure using the sealing membrane of the present embodiment will be described. Here, a case where the hollow seal structure is an electronic component device and the sealed body is a SAW device will be described.

Fig. 2 is a schematic cross-sectional view for explaining an embodiment of a method for manufacturing a semiconductor device as an electronic component device, which is an embodiment of a method for manufacturing a hollow sealed structure. In the manufacturing method of the present embodiment, first, a hollow structure including a substrate 30 and a plurality of SAW devices 20 arranged in parallel on the substrate 30 with bumps 40 interposed therebetween is prepared as a sealed body (an object to be embedded), and then the surface of the substrate 30 on the SAW device 20 side is opposed to the surface of the sealing film 10 with a support on the sealing film 2 side (fig. 2 (a)). Here, the hollow structure 60 has a hollow region 50, and the SAW device 20 has a movable portion on the surface 20a on the hollow region 50 side (substrate 30 side).

Next, the sealing film 2 is pressed (laminated) against the SAW device 20 under heating, thereby embedding the SAW device 20 in the sealing film 2, and then the sealing film 2 embedding the SAW device 20 is cured, thereby obtaining a cured product of the sealing film (a sealed portion including a cured product of the resin composition) 2a (fig. 2 (b)). Thereby, the electronic component device 100 can be obtained.

The laminator used for lamination is not particularly limited, and examples thereof include roll type laminators, air bag type laminators, and the like. The laminator may be of a gas-bag type capable of vacuum pressurization from the viewpoint of excellent embedding properties.

Lamination is generally carried out at a temperature less than or equal to the softening point of the support. The lamination temperature (sealing temperature) is preferably in the vicinity of the lowest melt viscosity of the sealing film. The laminating temperature is, for example, 60 to 140 ℃. The pressure at the time of lamination varies depending on the size, density, and the like of the sealed body to be embedded (for example, an electronic component such as a semiconductor element). The pressure during lamination may be, for example, in the range of 0.2 to 1.5MPa, or in the range of 0.3 to 1.0 MPa. The laminating time is not particularly limited, and may be 20 to 600 seconds, 30 to 300 seconds, or 40 to 120 seconds.

The curing of the sealing film may be performed, for example, under the atmosphere or under an inert gas. The curing temperature (heating temperature) is not particularly limited, and may be 80 to 280 ℃, 100 to 240 ℃, or 120 to 200 ℃. If the curing temperature is 80 ℃ or higher, the curing of the sealing film proceeds sufficiently, and the occurrence of troubles tends to be suppressed. When the curing temperature is 280 ℃ or lower, thermal damage to other materials tends to be suppressed. The curing time (heating time) is not particularly limited, and may be 30 to 600 minutes, 45 to 300 minutes, or 60 to 240 minutes. When the curing time is within these ranges, the curing of the sealing film proceeds sufficiently, and more favorable production efficiency can be obtained. In addition, a plurality of conditions may be combined.

In the present embodiment, a plurality of electronic component devices 200 may be obtained by further singulating the electronic component device 100 with a dicing saw or the like (fig. 2 (c)).

In the method of manufacturing a hollow seal structure according to the present embodiment, the sealing material can be sufficiently prevented from flowing into the hollow region 50 between the substrate 30 and the sealed body while ensuring excellent embedding properties with respect to the sealed body (for example, the SAW device 20).

In the present embodiment, the hollow seal structure (electronic component device) including the SAW device 20 embedded in the cured product 2a is obtained by sealing the SAW device 20 with the sealing film 2 by a lamination method and then thermally curing the sealing film 2, but the seal structure may be obtained by compression molding using a compression molding apparatus or may be obtained by press molding using a hydraulic press. The temperature (sealing temperature) at which the sealed body is sealed by compression molding and oil pressure pressing may be the same as the above-described lamination temperature.

Although the preferred embodiments of the present invention have been described above, the present invention is not necessarily limited to the above embodiments, and can be modified as appropriate within the scope not departing from the gist thereof.