阅读说明：本技术 放射线敏感性组合物的处理方法 (Method for treating radiation-sensitive composition ) 是由 浅冈高英 新木利治 藤井总一郎 吉田知识 于 2021-04-09 设计创作，主要内容包括：本发明提供一种即使使用LED光源,也能够对放射线敏感性组合物赋予高的透射性、抑制气泡的产生的放射线敏感性组合物的处理方法。本发明的放射线敏感性组合物的处理方法的特征在于,放射线敏感性组合物具有：作为具有酸基的自由基聚合性化合物(a)、具有环氧基的自由基聚合性化合物(b)、以及其他自由基聚合性化合物(c)的共聚物的可溶于碱水溶液的树脂(A)和放射线敏感性产酸化合物(B),其中,所述方法包含下述工序(α)：从LED元件对放射线敏感性组合物照射主峰值波长在375nm以上且395nm以下的范围内的紫外线,提高放射线敏感性组合物的透射率。(The invention provides a method for treating a radiation-sensitive composition, which can impart high transmittance to the radiation-sensitive composition and suppress the generation of bubbles even when an LED light source is used. The method for treating a radiation-sensitive composition of the present invention is characterized in that the radiation-sensitive composition comprises: an aqueous alkali solution-soluble resin (A) and a radiation-sensitive acid-generating compound (B) which are copolymers of a radically polymerizable compound (a) having an acid group, a radically polymerizable compound (B) having an epoxy group, and another radically polymerizable compound (c), wherein the method comprises the following step (a): the radiation-sensitive composition is irradiated with ultraviolet rays having a main peak wavelength in a range of 375nm to 395nm from the LED element, thereby improving the transmittance of the radiation-sensitive composition.)

1. A method for treating a radiation-sensitive composition, the radiation-sensitive composition having:

an aqueous alkali solution-soluble resin (A) which is a copolymer of a radical polymerizable compound (a) having an acid group, a radical polymerizable compound (b) having an epoxy group, and another radical polymerizable compound (c), and

a radiation-sensitive acid-generating compound (B);

wherein the method comprises the following step (α):

the radiation-sensitive composition is irradiated with ultraviolet rays having a main peak wavelength in a range of 375nm to 395nm from an LED element, and the transmittance of the radiation-sensitive composition is improved.

2. The method of treating a radiation-sensitive composition according to claim 1, wherein the half-value width of the ultraviolet ray is 20nm or less.

3. The method of treating a radiation-sensitive composition according to claim 1, wherein the intensity of light at 365nm of the ultraviolet ray is less than 10% relative to the intensity of light at the main peak wavelength.

4. The method of treating a radiation-sensitive composition according to claim 2, wherein the light intensity at 365nm of the ultraviolet light is less than 10% relative to the light intensity at the main peak wavelength.

5. The method of treating a radiation-sensitive composition according to claim 3, wherein the step (α) is a step of irradiating the radiation-sensitive composition with the ultraviolet light from the LED element via a filter that cuts light having a wavelength of 365nm or less.

6. The method of treating a radiation-sensitive composition according to claim 4, wherein the step (α) is a step of irradiating the radiation-sensitive composition with the ultraviolet light from the LED element via a filter that cuts light having a wavelength of 365nm or less.

7. The method for treating a radiation-sensitive composition according to any one of claims 1 to 6, wherein the radiation-sensitive acid-generating compound (B) is a 1, 2-quinonediazide compound.

8. The method for treating a radiation-sensitive composition according to any one of claims 1 to 6, wherein the proportion of the radiation-sensitive acid-generating compound (B) in the radiation-sensitive composition is 15 to 30 parts by mass with respect to 100 parts by mass of the resin (A).

9. The method for treating a radiation-sensitive composition according to any one of claims 1 to 6, wherein the other radical polymerizable compound (c) is a structural unit derived from at least 1 monomer selected from the group consisting of a (meth) acrylate having an alicyclic structure, a (meth) acrylate having an aromatic ring structure, an aromatic vinyl compound, an N-substituted maleimide compound, and a vinyl compound having a heterocyclic structure.

10. The method for treating a radiation-sensitive composition according to any one of claims 1 to 6, wherein the method comprises:

a step (beta 1) of forming a base film,

a step (β 2) of applying the radiation-sensitive composition to an upper layer of the base film formed by the step (β 1), and

a step (β 3) of sequentially performing, after the step (β 2), respective processes of pre-baking, exposure, and development on the radiation-sensitive composition;

wherein the step (α) is performed after the step (β 3).

11. The method of treating a radiation-sensitive composition according to claim 7, wherein the proportion of the radiation-sensitive acid-generating compound (B) in the radiation-sensitive composition is 15 to 30 parts by mass with respect to 100 parts by mass of the resin (A).

12. The method of treating a radiation-sensitive composition according to claim 11, wherein the other radical polymerizable compound (c) is a structural unit derived from at least 1 monomer selected from the group consisting of a (meth) acrylate having an alicyclic structure, a (meth) acrylate having an aromatic ring structure, an aromatic vinyl compound, an N-substituted maleimide compound, and a vinyl compound having a heterocyclic structure.

13. The method of treating a radiation-sensitive composition according to claim 12, characterized in that the method has:

a step (beta 1) of forming a base film,

a step (β 2) of applying the radiation-sensitive composition to an upper layer of the base film formed by the step (β 1), and

a step (β 3) of sequentially performing, after the step (β 2), respective processes of pre-baking, exposure, and development on the radiation-sensitive composition;

wherein the step (α) is performed after the step (β 3).

14. The method of treating a radiation-sensitive composition according to claim 7, wherein the other radical polymerizable compound (c) is a structural unit derived from at least 1 monomer selected from the group consisting of a (meth) acrylate having an alicyclic structure, a (meth) acrylate having an aromatic ring structure, an aromatic vinyl compound, an N-substituted maleimide compound, and a vinyl compound having a heterocyclic structure.

15. The method of treating a radiation-sensitive composition according to claim 14, characterized in that the method has:

a step (beta 1) of forming a base film,

a step (β 2) of applying the radiation-sensitive composition to an upper layer of the base film formed by the step (β 1), and

a step (β 3) of sequentially performing, after the step (β 2), respective processes of pre-baking, exposure, and development on the radiation-sensitive composition;

wherein the step (α) is performed after the step (β 3).

16. The method of treating a radiation-sensitive composition according to claim 8, wherein the other radical polymerizable compound (c) is a structural unit derived from at least 1 monomer selected from the group consisting of a (meth) acrylate having an alicyclic structure, a (meth) acrylate having an aromatic ring structure, an aromatic vinyl compound, an N-substituted maleimide compound, and a vinyl compound having a heterocyclic structure.

17. The method of treating a radiation-sensitive composition according to claim 7, characterized in that the method has:

a step (beta 1) of forming a base film,

a step (β 2) of applying the radiation-sensitive composition to an upper layer of the base film formed by the step (β 1), and

a step (β 3) of sequentially performing, after the step (β 2), respective processes of pre-baking, exposure, and development on the radiation-sensitive composition;

wherein the step (α) is performed after the step (β 3).

18. The method of treating a radiation-sensitive composition according to claim 17, wherein the proportion of the radiation-sensitive acid-generating compound (B) in the radiation-sensitive composition is 15 to 30 parts by mass with respect to 100 parts by mass of the resin (a).

19. The method of treating a radiation-sensitive composition according to claim 8, characterized in that the method has:

a step (beta 1) of forming a base film,

a step (β 2) of applying the radiation-sensitive composition to an upper layer of the base film formed by the step (β 1), and

a step (β 3) of sequentially performing, after the step (β 2), respective processes of pre-baking, exposure, and development on the radiation-sensitive composition;

wherein the step (α) is performed after the step (β 3).

20. The method of treating a radiation-sensitive composition according to claim 16, characterized in that the method has:

a step (beta 1) of forming a base film,

a step (β 2) of applying the radiation-sensitive composition to an upper layer of the base film formed by the step (β 1), and

a step (β 3) of sequentially performing, after the step (β 2), respective processes of pre-baking, exposure, and development on the radiation-sensitive composition;

wherein the step (α) is performed after the step (β 3).

21. The method of treating a radiation-sensitive composition according to claim 9, characterized in that the method has:

a step (beta 1) of forming a base film,

a step (β 2) of applying the radiation-sensitive composition to an upper layer of the base film formed by the step (β 1), and

a step (β 3) of sequentially performing, after the step (β 2), respective processes of pre-baking, exposure, and development on the radiation-sensitive composition;

wherein the step (α) is performed after the step (β 3).

Technical Field

The present invention relates to a method for treating a radiation-sensitive composition, and more particularly, to a bleaching treatment method for improving transmittance of a radiation-sensitive composition.

Background

In display devices such as liquid crystal panels and organic EL panels, a fine semiconductor element is provided corresponding to each pixel, and a composition exhibiting a property sensitive to light (radiation sensitivity) is widely used as an insulating material (resist material) in the element.

For example, it is known that in the production process of a display device, the light transmittance and durability (heat resistance) of a pattern after exposure and development are improved by applying a radiation-sensitive composition and prebaking the composition and then irradiating the pattern with ultraviolet rays. In this way, the treatment for improving the transmittance of the film to visible light by irradiating the film to be patterned with ultraviolet light is sometimes referred to as "bleaching treatment". The treatment is caused by decomposing the photosensitive material contained in the radiation-sensitive composition with ultraviolet rays.

For example, patent document 1 describes that a resist pattern is subjected to a bleaching treatment by irradiating i-rays, i.e., ultraviolet rays having a wavelength of 365 nm.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2017-037169

Disclosure of Invention

Problems to be solved by the invention

The light source for the bleaching treatment is generally a lamp such as a high-pressure mercury lamp. Patent document 1 also describes "i-ray", and therefore estimates a mercury spectrum, and although there is no written description, it is understood that a high-pressure mercury lamp is intended to be used.

In contrast, with the recent technological progress of solid-state light sources, studies on bleaching treatment using UV-LEDs are being conducted.

However, as a result of intensive studies by the present inventors, it has been found that when an LED light source is used for the bleaching treatment, a problem that a desired transmittance (bleaching ability) cannot be obtained and a problem that foaming occurs inside the radiation-sensitive composition tend to occur.

In view of the above problems, an object of the present invention is to provide a method for treating a radiation-sensitive composition, which can provide a high transmittance to the radiation-sensitive composition and further suppress the generation of bubbles even when an LED light source is used.

Means for solving the problems

The present invention relates to a method for treating a radiation-sensitive composition, the radiation-sensitive composition comprising:

an aqueous alkali solution-soluble resin (A) which is a copolymer of a radical polymerizable compound (a) having an acid group, a radical polymerizable compound (b) having an epoxy group, and another radical polymerizable compound (c), and

a radiation-sensitive acid-generating compound (B);

wherein the method comprises the following step (α):

the radiation-sensitive composition is irradiated with ultraviolet rays having a main peak wavelength in a range of 375nm to 395nm from an LED element, and the transmittance of the radiation-sensitive composition is improved.

When a film containing a radiation-sensitive composition is subjected to a bleaching treatment, a mercury lamp has been generally used in the past as described in the section "problem to be solved by the present invention". This is because it is empirically known that the radiation-sensitive acid-generating compound exhibits high photosensitivity to 365nm (i-ray), which is 1 kind of the peak wavelength of light emitted from the mercury lamp.

Based on the above findings, the present inventors prepared LED elements exhibiting a main peak wavelength of around 365nm, and performed bleaching treatment by irradiating a treatment target film (hereinafter, may be referred to as "target film") containing a radiation-sensitive composition with ultraviolet light emitted from the LED elements. Then, it was confirmed that the transmittance of the target film after the treatment was lower than the desired value, and the satisfactory transmittance performance was not achieved.

Note that, the above description is made in terms of the main peak wavelength being "near 365 nm" because, even in the case of an element obtained as an LED element having a main peak wavelength of 365nm, individual differences may occur between elements, and the main peak wavelength may cause an error in manufacturing of about ± 10 nm.

Further, it was confirmed that several bubbles were present in the treated target film. Since the object film including the radiation-sensitive composition functions as an insulating film in a liquid crystal panel, an organic EL panel, or the like as described above, if bubbles are visually recognized from the light extraction surface side, the display performance of the device or the like is affected.

On the other hand, the present inventors have tried to prepare an LED element which intentionally shifts the wavelength to the side of a wavelength longer than i-ray (365nm) and emits light having a main peak wavelength of 375nm or more and 395nm or less, and irradiate the object film with ultraviolet rays from the LED element. Surprisingly, it was found that the transmittance was improved and the amount of bubbles generated in the film could be significantly reduced as compared with the case of irradiating ultraviolet rays from an LED element having a main peak wavelength of 365nm or so. This fact is considered to be an extremely surprising effect in view of the conventional knowledge that a radiation-sensitive acid-generating compound represented by a quinonediazide compound exhibits high sensitivity to 365 nm.

In the present specification, "main peak wavelength" means a wavelength at which the light intensity is highest in the spectrum.

The ultraviolet ray may be an ultraviolet ray having a half-value width of 20nm or less.

By using an LED element that emits ultraviolet light exhibiting a spectrum with a half-value width of 20nm, the light intensity of a 365nm component contained in the ultraviolet light can be sufficiently reduced with respect to the light intensity of the main peak wavelength. This can achieve both improvement of transmittance and suppression of bubble generation.

The light intensity at 365nm of the ultraviolet light may be less than 10% relative to the light intensity at the main peak wavelength.

The step (α) may be a step of irradiating the radiation-sensitive composition with the ultraviolet light from the LED element via a filter for cutting off light having a wavelength of 365nm or less.

The radiation-sensitive acid generating compound (B) may be a 1, 2-quinonediazide compound.

The proportion of the radiation-sensitive acid-generating compound (B) in the radiation-sensitive composition may be 15 to 30 parts by mass with respect to 100 parts by mass of the resin (a).

The other radical polymerizable compound (c) may be a structural unit derived from at least 1 monomer selected from the group consisting of a (meth) acrylate having an alicyclic structure, a (meth) acrylate having an aromatic ring structure, an aromatic vinyl compound, an N-substituted maleimide compound, and a vinyl compound having a heterocyclic structure.

The effect of suppressing foaming upon irradiation with ultraviolet light can be enhanced by including a cyclic structure such as a (meth) acrylate having an alicyclic structure, a (meth) acrylate having an aromatic ring structure, an aromatic vinyl compound, an N-substituted maleimide compound, or a vinyl compound having a heterocyclic structure in the compound constituting the resin.

The resin (a) may contain a crosslinkable group-containing structural unit. With this configuration, the effect of suppressing foaming during ultraviolet irradiation can be further improved.

The method of treating the radiation-sensitive composition may include:

a step (beta 1) of forming a base film,

a step (β 2) of applying the radiation-sensitive composition to an upper layer of the base film formed by the step (β 1), and

a step (β 3) of sequentially performing, after the step (β 2), respective processes of pre-baking, exposure, and development on the radiation-sensitive composition;

wherein the step (α) is performed after the step (β 3).

By the above method, for example, the transmittance of the insulating film after the pattern formation in the display device or the like can be improved.

Effects of the invention

The method of the present invention can provide a subject film containing a radiation-sensitive composition with high transmittance and suppress the generation of bubbles in the film, even when an LED light source is used.

Drawings

Fig. 1 is a view schematically showing one step of the method for treating a radiation-sensitive composition of the present invention.

Fig. 2 is a diagram showing an example of a spectrum of ultraviolet rays emitted from the LED element.

FIG. 3 is a graph obtained by superimposing ultraviolet spectra having main peak wavelengths of 365nm, 385nm, and 405 nm.

Fig. 4 is another view schematically showing a step of the method for treating a radiation-sensitive composition of the present invention.

[ description of symbols ]

1: object film

2: layer (lower layer of object film)

3: light source

4: LED element

5: filter with a filter element having a plurality of filter elements

L1: ultraviolet ray

Detailed Description

Fig. 1 is a view schematically showing one step of the method for treating a radiation-sensitive composition of the present invention. However, fig. 1 is a schematic diagram, and the actual size ratio does not necessarily coincide with the size ratio in the drawing.

A film to be processed (hereinafter referred to as "target film 1") is laminated on the layer 2 and subjected to a patterning process. The subject film 1 is made of a material (radiation-sensitive composition) exhibiting radiation sensitivity. The detailed description of the materials is described later. Wherein layer 2 corresponds to the "base film".

Ultraviolet light L1 having a main peak wavelength of 375nm to 395nm is irradiated from a light source 3 on which an LED element 4 is mounted to the target film 1 (corresponding to step (α)). Fig. 2 shows an example of the spectrum of ultraviolet L1. The spectrum shown in fig. 2 corresponds to the case where the LED element 4 is an element that emits ultraviolet light L1 having a main peak wavelength of 385 nm. In the spectrum shown in FIG. 2, the half-value width d λ is 13 nm. Among them, the half-value width d λ is preferably 20nm or less.

Such an LED element 4 is realized, for example, by including an active layer having a well layer made of InGaN or AlInGaN and a barrier layer made of InGaN or AlInGaN having a lower In composition than GaN or the well layer.

By irradiating the object film 1 with ultraviolet L1 having a main peak wavelength of 375nm or more and 395nm or less, the transmittance of the object film 1 is improved, and the generation of bubbles in the object film 1 is suppressed. This point will be described later with reference to examples.

Next, the material of the target film 1 will be described.

The subject film 1 contains a radiation-sensitive composition. The radiation-sensitive composition contains a resin (A), a radiation-sensitive acid-generating compound (B), and, if necessary, another compounding agent (C).

Resin (A)

The resin (a) is composed of a material having an alkali-soluble group and preferably exhibiting a property of being cured by heating. The resin (a) is obtained by radical copolymerization of a radical polymerizable compound (a) having an acid group, a radical polymerizable compound (b) having an epoxy group, and another radical polymerizable compound (c) in a solvent.

Specific examples of the radical polymerizable compound (a) having an acid group include:

examples of the monomer constituting the structural unit having a carboxyl group include unsaturated monocarboxylic acids such as crotonic (meth) acrylate and 4-vinylbenzoic acid; unsaturated dicarboxylic acids such as maleic acid, fumaric acid, citraconic acid, mesaconic acid, and itaconic acid;

examples of the monomer constituting the structural unit having a sulfonic acid group include vinylsulfonic acid, (meth) allylsulfonic acid, styrenesulfonic acid, (meth) acryloyloxyethylsulfonic acid, and the like;

examples of the monomer constituting the structural unit having a phenolic hydroxyl group include 4-hydroxystyrene, o-isopropenylphenol, m-isopropenylphenol, p-isopropenylphenol, hydroxyphenyl (meth) acrylate, and the like.

In addition, as the monomer, maleimide may be used.

Examples of the radical polymerizable compound (b) having an epoxy group include glycidyl (meth) acrylate, 3, 4-epoxycyclohexyl (meth) acrylate, 3, 4-epoxycyclohexylmethyl (meth) acrylate, 2- (3, 4-epoxycyclohexyl) ethyl (meth) acrylate, and 3, 4-epoxytricyclo [5.2.1.0 ]^2,6]Decyl (meth) acrylate, (3-methyloxetan-3-yl) methyl (meth) acrylate, (3-ethyloxetan-3-yl) (meth) acrylate, (oxetan-3-yl) methyl (meth) acrylate, (3-ethyloxetan-3-yl) methyl (meth) acrylate, and the like. In the present specification, the term "epoxy group" refers to a group containing an ethylene oxide group and a butylene oxide group.

In the case of obtaining the resin (a) (hereinafter, referred to as "copolymer (I)"), in the radical polymerization in the two-component system of the radical polymerizable compound (a) having an acid group and the radical polymerizable compound (b) having an epoxy group, the radical polymerizable compound having an epoxy group and an acid group may react during the polymerization reaction, causing crosslinking and gelling of the polymerization system.

Therefore, in order to obtain the copolymer (I), it is preferable to use another radical polymerizable compound (c) as the third component to suppress the reaction with the radical polymerizable compound having an epoxy group and an acid group. Examples of the other radical polymerizable compound (c) include alkyl (meth) acrylates, cycloalkyl (meth) acrylates, aromatic vinyl compounds, N-substituted maleimide compounds, heterocyclic ring-containing vinyl compounds, conjugated diene compounds, nitrogen-containing vinyl compounds, unsaturated dicarboxylic acid dialkyl ester compounds, and the like.

Specific examples of the other radically polymerizable compound (c) include:

examples of the alkyl (meth) acrylate include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-lauryl (meth) acrylate, and n-stearyl (meth) acrylate;

examples of the (meth) acrylate having an alicyclic structure include cyclohexyl (meth) acrylate, 2-methylcyclohexyl (meth) acrylate, dicyclopentyl (meth) acrylate, and tricyclo [5.2.1.0 ] meth) acrylate^2,5]Decan-8-yloxyethyl ester, isobornyl (meth) acrylate, and the like;

examples of the (meth) acrylate having an aromatic ring structure include phenyl (meth) acrylate, benzyl (meth) acrylate, and the like;

examples of the aromatic vinyl compound include styrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, α -methylstyrene, 2, 4-dimethylstyrene, 2, 4-diisopropylstyrene, 5-tert-butyl-2-methylstyrene, divinylbenzene, trivinylbenzene, tert-butoxystyrene, vinylbenzyldimethylamine, (4-vinylbenzyl) dimethylaminoethyl ether, N-dimethylaminoethylstyrene, N-dimethylaminomethylstyrene, 2-ethylstyrene, 3-ethylstyrene, 4-ethylstyrene, 2-tert-butylstyrene, 3-tert-butylstyrene, 4-tert-butylstyrene, diphenylethylene, and mixtures thereof, Vinylnaphthalene, vinylpyridine, and the like;

examples of the N-substituted maleimide compound include N-cyclohexylmaleimide, N-cyclopentylmaleimide, N- (2-methylcyclohexyl) maleimide, N- (4-ethylcyclohexyl) maleimide, N- (2, 6-dimethylcyclohexyl) maleimide, N-norbornylmaleimide, N-tricyclodecylmaleimide, N-adamantylmaleimide, N-phenylmaleimide, N- (2-methylphenyl) maleimide, N- (4-ethylphenyl) maleimide, N- (2, 6-dimethylphenyl) maleimide, N-cyclohexylmaleimide, N- (4-ethylcyclohexyl) maleimide, N-cyclohexylmaleimide, N- (4-methylcyclohexyl) maleimide, N- (2, 6-dimethylphenyl) maleimide, N-cyclohexylmaleimide, N- (4-ethylcyclohexyl) maleimide, N- (2-ethylcyclohexyl) maleimide, N- (4-dimethylcyclohexyl) maleimide, N- (4-ethylcyclohexyl) maleimide, N- (2-cyclohexylmaleimide, N-phenylmaleimide, N- (4-phenylmaleimide, N- (2-phenylmaleimide, N, n-benzylmaleimide, N-naphthylmaleimide, etc.;

examples of the vinyl compound having a heterocyclic structure include tetrahydrofurfuryl (meth) acrylate, tetrahydropyranyl (meth) acrylate, 5-ethyl-1, 3-dioxan-5-ylmethyl (meth) acrylate, 5-methyl-1, 3-dioxan-5-ylmethyl (meth) acrylate, (2-methyl-2-ethyl-1, 3-dioxolan-4-yl) methyl (meth) acrylate, 2- (meth) acryloyloxymethyl-1, 4, 6-trioxaspiro [4,6] undecane, (γ -butyrolactone-2-yl) acrylate, glycerol carbonate (meth) acrylate, (γ -lactam-2-yl) acrylate, and mixtures thereof, N- (meth) acryloyloxyethylhexahydrophthalimide, etc.;

examples of the conjugated diene compound include 1, 3-butadiene, isoprene, and the like;

examples of the nitrogen-containing vinyl compound include (meth) acrylonitrile, (meth) acrylamide, and the like;

examples of the unsaturated dicarboxylic acid dialkyl ester compound include diethyl itaconate and the like.

In addition, examples of the other monomer include monomers such as vinyl chloride, vinylidene chloride, and vinyl acetate, in addition to the above monomers.

The other radical polymerizable compound (c) is preferably a structural unit derived from at least 1 monomer selected from the group consisting of an alkyl (meth) acrylate, a (meth) acrylate having an alicyclic structure, (meth) acrylate having an aromatic ring structure, an aromatic vinyl compound, an N-substituted maleimide compound, and a vinyl compound having a heterocyclic structure, from the viewpoint of adjusting the glass transition temperature of the polymer component to suppress melt flow during thermal curing.

The copolymerization ratio of the radically polymerizable compound (a) having an acid group in the copolymer (I) is preferably 5 to 40% by mass, and particularly preferably 10 to 30% by mass. When the amount is less than 5% by mass, the resulting copolymer is not easily dissolved in an aqueous alkali solution, and therefore, development residue is easily generated, and it is difficult to form a sufficient pattern. On the other hand, if it exceeds 40 mass%, the solubility of the resulting copolymer in an aqueous alkali solution becomes too high, and it becomes difficult to prevent the dissolution of the radiation-irradiated portion, that is, the film reduction (film thickness loss) development.

The copolymerization ratio of the radical polymerizable compound (b) having an epoxy group in the copolymer (I) is preferably 10 to 70% by mass, and particularly preferably 20 to 50% by mass. If the amount is less than 10% by mass, the reaction of generating an acid by irradiating the radical polymerizable compound (a) having an acid group or the radiation-sensitive acid generating compound (B) with radiation hardly proceeds sufficiently, and the heat resistance of the pattern obtained from the composition becomes insufficient. When the amount exceeds 70% by mass, the storage stability of the copolymer (I) tends to be problematic.

The copolymerization ratio of the other radical polymerizable compound (c) in the copolymer (I) is preferably 10 to 70% by mass, and particularly preferably 30 to 50% by mass. When the amount is less than 10% by mass, gelation tends to occur during the polymerization reaction. If the amount exceeds 70% by mass, the amounts of the radical polymerizable compound (b) having an epoxy group and the radical polymerizable compound (a) having an acid group are relatively small, and therefore, the solubility of the resin in an aqueous alkali solution may be reduced, or the heat resistance of the pattern obtained from the composition may be insufficient.

Examples of the solvent used in the polymerization of the copolymer (I) include alcohols such as methanol and ethanol; ethers such as tetrahydrofuran; glycol ethers such as ethylene glycol monomethyl ether; cellosolve esters such as methyl cellosolve acetate; propylene glycol alkyl ether acetates such as propylene glycol methyl ether acetate and propylene glycol propyl ether acetate; other examples include aromatic hydrocarbons, ketones, esters, and the like.

As the polymerization catalyst in the radical polymerization, a general radical polymerization initiator can be used, and examples thereof include azo compounds such as 2,2 ' -azobisisobutyronitrile, 2 ' -azobis- (2, 4-dimethylvaleronitrile), 2 ' -azobis- (4-methoxy-2, 4-dimethylvaleronitrile); organic peroxides such as benzoyl peroxide, lauroyl peroxide, t-butyl peroxypivalate, and 1, 1-bis- (t-butylperoxy) cyclohexane, and hydrogen peroxide. When a peroxide is used as the radical polymerization initiator, a redox type initiator may be prepared by combining reducing agents.

The molecular weight and the distribution of the above copolymer (I) are not particularly limited as long as the solution of the radiation-sensitive composition forming the object film 1 can be uniformly applied.

Acid-producing Compound (B) sensitive to radiation

The radiation-sensitive acid-generating compound (B) is a compound that generates an acid by irradiation with light. As an example, the radiation-sensitive acid-generating compound is a quinone diazide compound (B1). The quinonediazide compound (B1) is an ester compound of a compound having 1 or more phenolic hydroxyl groups and 1, 2-naphthoquinonediazide-4-sulfonic acid or 1, 2-naphthoquinonediazide-5-sulfonic acid.

More specifically, examples of the quinone diazide compound (B1) include 1, 2-quinone diazide sulfonic acid esters such as 1, 2-quinone diazide sulfonic acid esters, 1, 2-naphthoquinone diazide sulfonic acid amides, and 1, 2-naphthoquinone diazide sulfonic acid amides.

Among them, the quinone diazide compound (B1) preferably includes compounds having good transparency in a visible light region of 400 to 800nm after irradiation with radiation, for example, 1, 2-benzoquinone diazide-4-sulfonate such as 2,3, 4-trihydroxybenzophenone, 2,3,4,4 '-tetrahydroxybenzophenone, 3' -methoxy-2, 3,4,4 '-tetrahydroxybenzophenone, 2', 5,5 '-tetramethyl-2', 4,4 '-trihydroxytriphenylmethane, 4, 4' - [1- [4- [1- (4-hydroxyphenyl) -1-methylethyl ] phenyl ] ethylene ] bisphenol, and 2,4, 4-trimethyl-2 ', 4', 7-trihydroxy-2-phenyl flavan, etc, 1, 2-naphthoquinonediazide-4-sulfonate or 1, 2-naphthoquinonediazide-5-sulfonate.

The quinone diazide compound (B1) may be used alone in 1 kind, or may be used in combination in 2 or more kinds.

The radiation-sensitive acid generating compound (B) is not limited to the quinonediazide compound (B1) and may be another acid generator (B2) as long as it generates an acid by irradiation with light. Examples of the acid generator (B2) include an onium salt compound, a halogen-containing compound, a sulfone compound, a sulfonic acid compound, a sulfonimide compound, and a diazomethane compound.

The amount of the radiation-sensitive acid-producing compound (B) added is preferably 5 to 100 parts by mass, more preferably 10 to 50 parts by mass, and particularly preferably 15 to 30 parts by mass, per 100 parts by mass of the resin (A). When the amount is less than 5 parts by mass, the amount of acid generated by light absorption is small, and thus a difference in solubility in an aqueous alkali solution before and after light irradiation cannot be caused, and pattern formation becomes difficult, and also, even in a reaction with an epoxy group of the copolymer (I), the amount of acid involved is small, and therefore, there is a possibility that a pattern obtained from the composition has poor heat resistance. When the amount is more than 100 parts by mass, most of the added radiation-sensitive acid-generating compound remains as it is even after short-time irradiation, and therefore the insolubilizing effect in an aqueous alkali solution may be too high to make development difficult.

In particular, by setting the amount of the radiation-sensitive acid-generating compound (B) to be added in the range of 15 to 30 parts by mass per 100 parts by weight of the resin (a), the effect of suppressing the amount of bubbles generated after the step (α) is performed can be improved.

Preparation of other compounding Agents (C)

From the viewpoint of improving the hardness and heat resistance of the target film 1, (meth) acrylic compounds, epoxy compounds, and the like shown below may be used in combination.

The (meth) acrylic compound is used to further improve the hardness, heat resistance, and the like of a coating film formed by self-polymerization of the (meth) acrylic compound during final heating. Examples of the (meth) acrylic compound include monofunctional (meth) acrylates, 2-functional (meth) acrylates, and 3-or more-functional (meth) acrylates. The epoxy compound is used for adjusting the reaction point of the copolymer (I) and an acid generated from the radiation-sensitive acid-generating compound by irradiation with radiation at the time of final heating.

Examples of the epoxy compound include bisphenol a type epoxy resins, phenol novolac type epoxy resins, cresol novolac type epoxy resins, cycloaliphatic epoxy resins, glycidyl ester type epoxy resins, glycidyl amine type epoxy resins, heterocyclic epoxy resins, and the like. Among them, phenol novolac type epoxy resins, cresol novolac type epoxy resins, cycloaliphatic epoxy resins, and glycidyl ester type epoxy resins are preferable from the viewpoint of being less likely to be colored after heat treatment.

The compounding agent (C) may contain a crosslinkable compound. Examples of the crosslinkable compound include compounds having a crosslinkable group such as an ethylene oxide group (1, 2-epoxy structure), a butylene oxide group (1, 3-epoxy structure), a methylol group, a vinyl group, a (meth) acryloyl group, and a cyclic carbonate group.

Among the crosslinkable groups, an ethylene oxide group (epoxy group), a butylene oxide group, a methylol group, and a combination thereof are preferable, an ethylene oxide group and a butylene oxide group are more preferable, and an ethylene oxide group is further preferable.

The compounding agent (C) may contain a surfactant. As the surfactant, for example, a fluorine-based surfactant, a silicone-based surfactant, and other surfactants can be used.

The radiation-sensitive composition contained in the subject film 1 can be easily prepared by uniformly mixing the above-described respective components. When mixing, the mixture is usually dissolved in an appropriate solvent and used in the form of a solution. As the solvent used, a solvent which uniformly dissolves the copolymer (I) and the radiation-sensitive acid-generating compound (B) and does not react with each component can be used.

Examples of the solvent include alcohols such as methanol and ethanol; ethers such as tetrahydrofuran; glycol ethers such as ethylene glycol monomethyl ether and ethylene glycol monoethyl ether; ethylene glycol alkyl ether acetates such as methyl cellosolve acetate and ethyl cellosolve acetate; diethylene glycols such as diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol dimethyl ether, and diethylene glycol methyl ethyl ether; propylene glycol alkyl ether acetates such as propylene glycol methyl ether acetate and propylene glycol propyl ether acetate; aromatic hydrocarbons such as toluene and xylene; ketones such as methyl ethyl ketone, cyclohexanone, and 4-hydroxy-4-methyl-2-pentanone; esters such as ethyl 2-hydroxypropionate, ethyl 2-hydroxy-2-methylpropionate, ethyl ethoxyacetate, ethyl glycolate, methyl 2-hydroxy-3-methylbutyrate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, methyl 3-ethoxypropionate, ethyl acetate, and butyl acetate.

In addition, high boiling point solvents such as N-methylformamide, N-dimethylformamide, N-methylformanilide, N-methylacetamide, N-dimethylacetamide, N-methylpyrrolidone, dimethyl sulfoxide, benzylethyl ether, dihexyl ether, acetonylacetone, isophorone, hexanoic acid, octanoic acid, 1-octanol, 1-nonanol, benzyl alcohol, benzyl acetate, ethyl benzoate, diethyl oxalate, diethyl maleate, γ -butyrolactone, ethylene carbonate, propylene carbonate, phenyl cellosolve acetate and the like may also be added.

Among these solvents, glycol ethers such as ethylene glycol monoethyl ether are preferable in terms of solubility, reactivity with each component, and easiness of forming a coating film; ethylene glycol alkyl ether acetates such as ethyl cellosolve acetate; esters such as ethyl 2-hydroxypropionate; diethylene glycols such as diethylene glycol monomethyl ether and diethylene glycol methyl ethyl ether, and propylene glycol alkyl ether acetates such as propylene glycol methyl ether acetate.

In addition, when preparing the composition solution, for example, a solution of the copolymer (I), a solution of the radiation-sensitive acid-generating compound, and a solution of other compounding agents may be prepared separately in advance, and these solutions may be mixed in a predetermined ratio immediately before use. The composition solution prepared as described above may be used after being filtered by using a membrane filter having a pore size of 0.2 μm or the like.

In the production of the target film 1, the above-mentioned composition solution is applied to a predetermined substrate surface (the upper surface of the layer 2 in fig. 1), and the solvent is removed by heating, thereby forming a desired coating film. The method of coating the surface of the substrate is not particularly limited, and various methods such as a spray coating method, a roll coating method, and a spin coating method can be used.

The heating conditions for coating the radiation-sensitive composition vary depending on the type and mixing ratio of the components, and are usually about 5 to 15 minutes at 70 to 90 ℃. Next, the obtained coating film is irradiated with ultraviolet light through a mask having a predetermined pattern, and then developed with a developer to remove unnecessary portions, thereby forming a pattern. Fig. 1 shows a coating film (target film 1) after pattern formation.

Examples of the developer include aqueous solutions of bases such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, aqueous ammonia, ethylamine, n-propylamine, diethylamine, di-n-propylamine, triethylamine, methyldiethylamine, dimethylethanolamine, triethanolamine, tetramethylammonium hydroxide, tetraethylammonium hydroxide, pyrrole, piperidine, 1, 8-diazabicyclo (5.4.0) -7-undecene, and 1, 5-diazabicyclo (4.3.0) -5-nonene. In addition, an aqueous solution obtained by adding an appropriate amount of a water-soluble organic solvent such as methanol or ethanol or a surfactant to the alkali aqueous solution may be used as the developer.

The developing time is usually 30 to 180 seconds, and the developing method may be any of a liquid coating method, a dipping method, and the like. After the development, the substrate is cleaned with flowing water for 30 to 90 seconds and air-dried with compressed air or compressed nitrogen, thereby removing unnecessary portions and forming a pattern. Then, for example, ultraviolet light is irradiated to change the acid generating compound remaining in the pattern, which is an unexposed portion, to an acid. The target film 1 having excellent heat resistance, transparency, hardness, and the like can be obtained by performing a heating treatment at a predetermined temperature, for example, 150 to 250 ℃ for a predetermined time, for example, 5 to 30 minutes on a hot plate, or 30 to 90 minutes in an oven, using a heating device such as a hot plate or an oven.

[ examples ]

The present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples. In the following, unless otherwise specified, parts are "parts by mass".

[ Synthesis example 1] (Synthesis of copolymer (I-1))

10 parts of 2, 2' -azobis (2, 4-dimethylvaleronitrile) and 200 parts of Propylene Glycol Monomethyl Ether Acetate (PGMEA) were placed in a flask equipped with a cooling tube and a stirrer. Subsequently, 15 parts of methacrylic acid, 20 parts of glycidyl methacrylate, 15 parts of 3, 4-epoxycyclohexylmethyl methacrylate and 50 parts of styrene were added, and after nitrogen substitution, polymerization was carried out by raising the temperature of the solution to 70 ℃ while slowly stirring, and maintaining the temperature for 5 hours, thereby obtaining a polymer solution containing the copolymer (I-1) as an alkali-soluble resin. The obtained polymer was reprecipitated in hexane, filtered, vacuum-dried, and purified, and the copolymer (I-1) was dissolved in PGMEA to prepare a solution having a polymer concentration of 30 mass%. The copolymer (I-1) had a weight average molecular weight (Mw) of 10,000 and a weight average molecular weight (Mw)/number average molecular weight (Mn) of 2.3.

[ Synthesis example 2-4] (Synthesis of copolymers (I-2) to (I-4))

Polymer solutions each containing the copolymers (I-2) to (I-4) were obtained in the same manner as in Synthesis example 1, except that the components were used in the kinds and blending amounts (parts by mass) shown in Table 1 below. In table 1, "-" indicates that the corresponding components are not used.

TABLE 1

The meanings of each symbol in table 1 are as follows.

MA: methacrylic acid

GMA: glycidyl methacrylate

ST: styrene (meth) acrylic acid ester

M-100: 3, 4-epoxycyclohexylmethyl methacrylate (manufactured by Cyclomer M100 Daicel Co., Ltd.)

DCM: methacrylic acid dicyclopentyl ester

CHMI: n-cyclohexyl maleimide

PMI: n-phenylmaleimide

PIPE: para-isopropenylphenol

And (3) OXMA: (3-Ethyloxetan-3-yl) methyl methacrylate

[ Components of radiation-sensitive composition ]

The following are a copolymer (I) (resin (a)), a radiation-sensitive acid-generating compound (B), and an organic solvent (C) as another compounding agent, which are used for the preparation of the radiation-sensitive compositions of examples and comparative examples.

Copolymer (I)

Copolymers I-1 to I-4: synthesis of copolymers (I-1) to (I-4) synthesized in Synthesis examples 1 to 4

Radiation sensitive acid producing compound (B)

B-1: condensate of 4, 4' - [1- [4- [1- (4-hydroxyphenyl) -1-methylethyl ] phenyl ] ethylene ] bisphenol (1.0 mol) and 1, 2-naphthoquinonediazide-5-sulfonyl chloride (2.0 mol)

B-2: condensate of 1,1, 1-tris (p-hydroxyphenyl) ethane (1.0 mol) with 1, 2-naphthoquinonediazide-5-sulfonyl chloride (2.0 mol)

Organic solvent (C)

C-1: diethylene glycol methyl ethyl Ether (EDM)

C-2: propylene Glycol Monomethyl Ether Acetate (PGMEA)

[ evaluation ]

The object film 1 was produced using the radiation-sensitive compositions of examples and comparative examples, and the following items were evaluated.

< example 1>

30 parts of a radiation-sensitive acid-generating compound (B-1) were mixed with 100 parts of the copolymer (I-1) in a polymer solution containing the copolymer (I-1) at a concentration of 30% by mass. The obtained mixture was dissolved in an organic solvent (C-1) so that the concentration of all components except the solvent was 30 mass%, and then filtered through a membrane filter having a pore size of 0.2 μm to prepare a radiation-sensitive composition.

< examples 2 to 9 and comparative examples 1 to 4>

Radiation-sensitive compositions of examples 2 to 9 and comparative examples 1 to 4 were prepared in the same manner as in example 1, except that the respective components of the types shown in table 2 below were used.

< evaluation of bubbles >

The radiation-sensitive compositions of examples and comparative examples shown in table 2 below were applied to a silicon substrate using a spinner, and then prebaked on a hot plate at 90 ℃ for 2 minutes to form a coating film having a thickness of 6.0 μm. Next, the reaction mixture was developed with a 2.38 mass% aqueous tetramethylammonium hydroxide solution at 23 ℃ for 60 seconds by the liquid filling method.

Subsequently, the sample was washed with ultrapure water for 1 minute and then dried, thereby producing a substrate for foam evaluation which simulates the target film 1. The evaluation substrate was measured at 2000m W/cm²Illuminance of 600mJ/cm²The exposure amount of (2) is an amount of irradiation of ultraviolet light L1 having a wavelength shown in table 2 from the light source 3 on which the LED element 4 is mounted.

After irradiation with ultraviolet light L1, the bubbles on the surface of the coating film were visually evaluated on a 6-point scale based on the following criteria.

(evaluation criteria)

0 failed to confirm the generation of bubbles.

1 bubbles were locally observed at the end of the coating film.

2 bubbles were observed over the entire surface of the coating film edge.

3 bubbles were observed locally in the center of the coating film.

4 bubbles were observed over the entire surface of the center of the coating film.

5 bubbles were observed over the entire surface of the center of the coating film, and a part of the coating film was chipped.

Since the coating film is applied by spin coating as described above, the end portions of the evaluation substrate are slightly thicker than the central portion. Since bubbles are more likely to be generated as the film thickness is thicker, it can be determined that bubbles are more likely to be generated when bubbles are generated in the central portion of the coating film, which is a region where the film thickness is relatively thin.

Evaluation of transmittance

The radiation-sensitive compositions of examples and comparative examples shown in Table 2 below were applied to a glass substrate ("Corning 7059" from Corning Inc.) using a spinner, and then prebaked on a hot plate at 90 ℃ for 2 minutes to form a coating film having a film thickness of 3.0 μm or 6.0. mu.m. Next, the reaction mixture was developed with a 2.38 mass% aqueous tetramethylammonium hydroxide solution at 23 ℃ for 60 seconds by the liquid filling method.

Subsequently, the substrate was washed with ultrapure water for 1 minute and dried to form a cured film simulating the target film 1. The evaluation substrate was 2000m W/cm²Illuminance of 600mJ/cm²The exposure amount of (2) is an amount of irradiation of ultraviolet light L1 having a wavelength shown in table 2 from the light source 3 on which the LED element 4 is mounted. Then, the mixture was heated at 230 ℃ for 30 minutes. This heating is performed for the purpose of promoting a crosslinking reaction (curing) of the crosslinking component present in the target film 1.

The transmittance of light having a wavelength in the range of 400nm to 800nm was measured for the evaluation substrate using a spectrophotometer ("150-20 type dual beam" manufactured by hitachi corporation), and the lowest value of the transmittance (also referred to as the lowest transmittance) of light having a wavelength in the range of 400nm to 800nm was evaluated for each glass substrate evaluation substrate.

Further, the same evaluation was performed on the evaluation substrates prepared in the same manner with the film thickness of the coating film set to 6.0 μm using the radiation-sensitive compositions of the examples and comparative examples shown in table 2 below.

The transmittance before irradiation with ultraviolet light L1 of the evaluation substrate produced with the coating film having a film thickness of 3.0 μm was 70%, and the transmittance before irradiation with ultraviolet light L1 of the evaluation substrate produced with the coating film having a film thickness of 6.0 μm was 52%.

The evaluation results of the radiation-sensitive compositions of examples 1 to 9 and comparative examples 1 to 4 and the subject film 1 formed using the compositions are shown in table 2 below.

TABLE 2

Fig. 3 is a graph obtained by superimposing the spectra of ultraviolet L1 having main peak wavelengths of 365nm, 385nm, and 405nm emitted from the light source 3 used in each example or comparative example. In the examples, the evaluation substrate was irradiated with ultraviolet light L1 from a light source 3 equipped with LED elements 4 having a main peak wavelength of 385 nm. In the comparative example, a light source 3 having an LED element 4 with a main peak wavelength of 365nm or a light source 3 having an LED element 4 with a main peak wavelength of 405nm was prepared, and ultraviolet light L1 was irradiated from each light source 3 to the evaluation substrate, unlike the light source 3 used in the examples.

As is clear from table 2, when example 1, comparative example 1 and comparative example 2 in which the radiation-sensitive composition was formed with the same material composition were compared, the transmittance was high regardless of the film thickness of the subject film 1 and the foaming in the film was suppressed in the case of irradiation with the ultraviolet ray L1 having a main peak wavelength of 385nm (example 1) as compared with the case of irradiation with the ultraviolet ray L1 having a main peak wavelength of 365nm or 405nm (comparative example 1 and comparative example 2).

Similarly, as is clear from table 2, when example 3, comparative example 3 and comparative example 4, in which the radiation-sensitive composition was formed with the same material composition, were compared, the transmittance was high regardless of the film thickness of the subject film 1 and foaming in the film was suppressed in the case of irradiation with the ultraviolet ray L1 having a main peak wavelength of 385nm (example 1) as compared with the case of irradiation with the ultraviolet ray L1 having a main peak wavelength of 365nm or 405nm (comparative example 1 and comparative example 2).

It is also understood that in any of examples 1 to 9 produced by appropriately changing the composition of the radiation-sensitive composition, the transmittance was high regardless of the film thickness of the object film 1 and the foaming in the film was suppressed by irradiating ultraviolet light L1 having a main peak wavelength of 385 nm.

It is considered that the generation of bubbles in the target film 1 by irradiating the target film 1 containing the radiation-sensitive composition with the ultraviolet ray L1 is caused by, for example, the reaction of the following formula (1) and generates nitrogen gas. The following formula (1) represents a reaction when the naphthoquinone diazide compound constituting the radiation-sensitive acid generating compound (B) is irradiated with ultraviolet light L1 (labeled as h ν in the following formula (1)).

[ CHEMICAL FORMULA NUMBER No. 1]

The reaction of the above formula (1) is likely to occur when the naphthoquinone diazide compound is irradiated with ultraviolet rays having a wavelength exhibiting high photosensitivity. That is, in the present invention, it is considered that the reaction of the formula (1) is progressed slowly by irradiating the object film 1 containing the radiation-sensitive acid-generating compound (B) with the ultraviolet ray L1 in the wavelength band in which the photosensitivity is intentionally slightly lowered, whereby the generation rate of the nitrogen gas is lowered. From the results in table 2, it was confirmed that the transmittance of the object film 1 was improved even when ultraviolet light L1 having a wavelength band in which the photosensitivity was slightly decreased, in this case, the main peak wavelength was 385nm, was irradiated.

As described in the "means for solving the problem" section, it is conceivable that the LED elements 4 have individual differences within a range of ± 10nm in the main peak wavelength depending on the accuracy at the time of manufacture and the environment at the time of use. In view of the above, it is understood that by irradiating the object film 1 with the ultraviolet light L1 having a main peak wavelength in the range of 375nm to 395nm from the LED element 4, the improvement of the transmittance and the suppression of the foaming can be achieved at the same time as in the respective examples.

[ other embodiments ]

As shown in fig. 4, the light source 3 is provided with a filter 5 for cutting off light having a wavelength of 365nm or less, and the ultraviolet light L1 emitted from the LED element 4 may be irradiated to the target film 1 in a state where light having a wavelength of 365nm or less is cut off by the filter 5. The filter 5 is formed of, for example, a dielectric multilayer film.