JPH075301A - Photosensitive composition for formation of microlens - Google Patents

Abstract

PURPOSE:To form a lens excellent in chemical resistance, etc., by incorporating an alkali-soluble resin, photosensitive agent comprising naphthoquinonediazido sulfonate, specified alicyclic epoxy thermosetting agent, and solvent. CONSTITUTION:This compsn. contains an alkali-soluble resin, photosensitive agent comprising 1,2,-naphthoquinonediazido sulfonate, thermosetting agent comprising a tetra-or higher functional alicyclic epoxy compd., and solvent. The alkali-soluble resin consists of, preferably, sturctural units expressed by formula or II. In formula I, II, R1 is a hydrogen atom or methyl group, R2 and R2 are hydrogen atoms, methyl groups, chlorine etc., A reprents OA1 (wherein A1 is hydrogen or alkyl group of 1-6 cardon number), k, m, z are intergers >1, and 1, n, x, y are integers including 0. By this method, a resist pattern with high sensitivity and high resolution can be obtd., and a lens having large refractive index, excellent transparency in a visible region, heat resistnace and chemical resistance can be obtd.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a color solid-state image pickup device,
The present invention relates to a micro-condensing lens material formed on a color filter of a color liquid crystal display device, etc., and a photosensitive composition that can be used for applications using a micro-lens-shaped concavo-convex pattern and a heat-cured concavo-convex pattern.

[0002]

2. Description of the Related Art In recent years, with the spread of color video cameras using image pickup devices, the demand for high-quality image pickup devices is increasing. Then, in order to cope with high image quality, a micro condenser lens is formed. That is, the micro condenser lens is usually formed on the uppermost part of the color filter layer, the intermediate film, the protective film, etc. formed on the image pickup device,
This lens is disclosed in JP-A-1-91103 and JP-A-1-24.
6505, JP-A-1-257901, JP-A 1-2
As shown in Japanese Patent No. 63601 and the like, there are effects such as improvement in sensitivity of the element and reduction in aliasing distortion of an output signal of the element, and formation of a micro focusing lens is an indispensable condition for a color solid-state image pickup element. ing.

Further, in color liquid crystal display elements, the formation of microlenses is being studied, and in principle, the same function as that of the image pickup element is required.

Further, a reflector of a liquid crystal display element as described in JP-A-4-315129 and JP-A-5-34730, or an interlayer for a thin film magnetic head described in JP-A-4-63351 and the like. Insulation layer etc. are patterned,
The uneven shape formed after thermosetting can be used.
Although there is no regulation regarding transparency and refractive index, it is expected that the specifications will be the same or stricter with respect to other functions, especially durability such as chemical resistance and heat resistance.

There are various methods for forming a micro condenser lens, for example, Japanese Patent Laid-Open Nos. 1-246505 and 3-53.
No. 223702, a transparent photosensitive resin is applied on the surface protective film, exposed and developed so that the resin layer remains in the portion corresponding to the photodiode, and then the pattern is heat-treated.

By the way, the performance of the image pickup element is changing day by day, and the characteristics required for the micro condenser lens are becoming severer day by day. The basic required characteristics of lens forming materials are high refractive index, high transparency in the visible light range, excellent heat resistance after pattern deformation, chemical resistance, and light resistance. It has excellent resisting properties, high sensitivity and high resolution. In particular, regarding the lens forming ability, it is necessary to have a curvature with sufficient light collecting ability with the recent miniaturization of photodiodes. For example, in the forming method of heat-treating the above pattern, the dimension of the pattern changes. It is closer to the ideal to have roundness without doing it.

[0007]

For example, when a positive type photoresist for semiconductor integrated circuit is used as a microlens material, a micro condenser lens can be formed by coating, prebaking, exposing, developing and heat treatment.

However, practical use of this lens is impossible. There are various reasons for this, but problems such as poor chemical resistance, pattern flow when reheating after lens formation, and extremely low transparency can be considered.

Therefore, in order to solve this problem, an alkali-soluble resin, 1,2-naphthoquinonediazide sulfonic acid ester as a photosensitizer, and heat curing for imparting heat resistance and chemical resistance when forming a lens by heat treatment. Agent,
In particular, it provides a positive photosensitive material for microlenses, which comprises a melamine-based curing agent and a solvent (JP-A-3-223).
702).

However, this positive type photosensitive material also has some dissatisfaction with respect to durability such as chemical resistance and is not yet sufficient.

The present invention has been made in view of the above problems, and an object thereof is to provide a material which sufficiently satisfies the above-mentioned required characteristics.

[0012]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies based on such a background, and as a result, an alkali-soluble resin having an aromatic ring component and a carboxylic acid component as a base polymer, or vinylphenol. Excellent transparency when using polymers, vinylphenol copolymers, novolak resins that are polycondensates of phenols and aldehydes, partially hydrogenated products of each resin, or resins in which some of the hydroxyl groups of each resin are modified And a positive photosensitive composition composed of a naphthoquinonediazide-based photosensitizer, a tetrafunctional or more alicyclic epoxy compound that imparts heat resistance and chemical resistance during lens formation as a thermosetting agent, and a solvent. The inventors have found that the above problems can be solved and completed the present invention. That is, the present invention is an alkali-soluble resin, in particular, a resin comprising a structural unit represented by a predetermined general formula, or a vinylphenol polymer, vinylphenol copolymer, novolak which is a polycondensation product of phenols and aldehydes. A resin or a hydrogenated product of each resin or a resin in which a part of the hydroxyl group is modified, 1,2-naphthoquinonediazide sulfonic acid ester as a photosensitizer, a tetrafunctional or more alicyclic epoxy compound as a thermosetting agent, and a micro containing a solvent It is a photosensitive composition for forming a lens.

The present invention will be described in more detail below.

The alkali-soluble resin in the present invention is not particularly limited as long as it is soluble in a solvent and can form a film. This is for imparting the solubility of the binder and the alkaline developer as the photosensitive composition. In particular,
The alkali-soluble resin of the present invention is preferably a resin having a structural unit represented by the following general formula (1) or general formula (2) in order to maintain transparency even when reheated.

[0015]

[Chemical 3]

[Wherein R ₁ represents hydrogen or a methyl group,
A is OA ₁ or NA ₂ A ₃ (A ₁ , A ₂ and A ₃ are respectively hydrogen, an alkyl group having 1 to 6 carbon atoms, and 6 to 1 carbon atoms)
An allyl group having up to 2 or an aralkyl group having 7 to 12 carbon atoms is shown. ), K and m each represent an integer of 1 or more, and l and n each represent an integer including 0. ]

[0017]

[Chemical 4]

[In the formula, R ₁ represents hydrogen or a methyl group,
R ₂ and R ₃ each represent hydrogen, a methyl group, chlorine or bromine, A is OA ₁ or NA ₂ A ₃ (A ₁ , A ₂ and A ₃ are each hydrogen, an alkyl group having 1 to 6 carbon atoms, Carbon number 6
It shows an allyl group having 1 to 12 or an aralkyl group having 7 to 12 carbon atoms. ), X and y are integers including 0, and z is an integer of 1 or more. The alkyl group represented by A _{1 to} A ₃ in the above formula is a methyl group, an ethyl group, an n-propyl group, an isopropyl group,
Examples thereof include an n-butyl group, an isobutyl group, a t-butyl group, an n-amyl group, an isoamyl group, an n-hexyl group and a cyclohexyl group. Examples of the allyl group include a phenyl group, a tolyl group, a xylyl group and ethylphenyl. Group, naphthyl group and the like, aralkyl group includes benzyl group and phenethyl group, and the benzene ring may be substituted with halogen such as chlorine and bromine, nitro group and cyano group.

Examples of the alkali-soluble resin include vinylphenol polymers, vinylphenol copolymers, novolak resins which are polycondensates of phenols and aldehydes, partial hydrogenated products of each resin, and hydroxyl groups of each resin. A resin partially modified is also suitable.

The method for synthesizing the alkali-soluble resin in the present invention is not particularly limited, but it can be synthesized, for example, by the following method.

The alkali-soluble resin composed of the structural unit represented by the general formula (1) is obtained by synthesizing an (α-methyl) styrene / maleic anhydride copolymer by solution or bulk radical polymerization according to a conventional method, and then alcohol. It can be synthesized by esterification or amidation reaction with phenols or amines. Further, the (α-methyl) styrene / maleic acid ester copolymer can be synthesized by a conventional method such as solution or bulk radical polymerization.

The alkali-soluble resin composed of the structural unit represented by the general formula (2) includes (α-methyl) styrene / (meth) acrylic acid and (α-methyl) styrene / (meth) acrylic acid ester copolymer. According to a conventional method, it can be synthesized by solution radical polymerization or the like, and then esterification, amidation or hydrolysis. It can also be synthesized by a method of multi-component copolymerization with an esterified or amidated monomer, and a method of esterifying or amidating poly (meth) acrylic acid.

The vinylphenol (co) polymer can be synthesized by radical polymerization or cationic polymerization, and the novolac resin can be synthesized by polycondensation of phenol, cresols and aldehydes such as formaldehyde. Further, the method of hydrogenating the vinylphenol polymer or the novolac resin is not particularly limited.
103604, JP-A-2-4254, JP-A-2-2
It can be synthesized by the methods of 9751 and JP-A-2-9752. The modification of the hydroxyl group of the vinylphenol polymer or the novolak resin can be performed by a reaction such as alkylation, acylation, sulfonylation and the like. For example, alkylation can be synthesized by reacting a resin with an alkyl halide under a basic catalyst, and acylation and sulfonylation can be performed by reacting a resin with a carboxylic acid, sulfonic acid, carbonyl halide or sulfonyl halide with an acid catalyst or a base. It can be synthesized by reacting under a neutral catalyst. Further, as the copolymerization component of the vinylphenol copolymer, a monomer having a double bond capable of radical copolymerization can be used, and examples thereof include (meth) acrylic acid such as methyl acrylate, methyl methacrylate, and hydroxyethyl methacrylate. Examples thereof include acid esters, acid amides such as acrylamide and methacrylamide, acrylonitrile, and styrene.

As the photosensitizer in the present invention, 1,2-
Naphthoquinone diazide sulfonic acid ester, which is for imparting a dissolution inhibiting effect to the alkali developing solution in the unexposed area and a dissolution promoting effect in the exposed area.

The ester component of 1,2-naphthoquinonediazide sulfonic acid ester is not particularly limited as long as it can maintain the characteristics, but for example, 2,4
-Dihydroxybenzophenone, 2,3,4-trihydroxybenzophenone, 2,3,4,4'-tetrahydroxybenzophenone, 2,2 ', 3,4,4'-pentahydroxybenzophenone, phenol, 1,3-dihydroxy Examples thereof include benzene, 1,3,5-trihydroxybenzene, methyl gallate, ethyl gallate, and phenyl gallate.

The thermosetting agent in the present invention is a tetrafunctional or higher-functional alicyclic epoxy compound, which imparts heat resistance and chemical resistance when a lens is formed by heat treatment, and is tetrafunctional. The compound containing the alicyclic epoxy group is not particularly limited, and examples thereof include an oligomer, a polymer, and a polymer represented by the following general formula (3):
Functional alicyclic epoxy resin [commercial item, EPOLIDE (trademark)
GT-400 (manufactured by Daicel Chemical Industries)] and the like. The alicyclic epoxy compound having a functionality of 4 or more is selected as the thermosetting agent in the present invention because it has an excellent lens shape and improves the chemical resistance of the cured product.

[0027]

[Chemical 5]

[In the formula, R ₄ represents hydrogen or a methyl group,
a represents an integer of 4 or more. ] Further, as a thermosetting agent, as long as the characteristics are not deteriorated,
Other thermosetting agents, such as other epoxy-based, melamine-based,
You may add an isocyanate type | system | group, a polyfunctional unsaturated compound, etc. In particular, in order to obtain sufficient curing characteristics, epoxy type and melamine type are preferable. For example, other epoxy type curing agents include n-butyl glycidyl ether, 2-ethoxyhexyl glycidyl ether, phenyl glycidyl ether, and allyl glycidyl ether. , Ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, glycerol polyglycidyl ether,
Glycidyl ethers such as sorbitol polyglycidyl ether, adipic acid diglycidyl ester, o-phthalic acid diglycidyl ester and other glycidyl esters, 3,
4-epoxycyclohexylmethyl (3,4-epoxycyclohexane) carboxylate, 3,4-epoxy-6-methylcyclohexylmethyl (3,4-epoxy-6-methylcyclohexane) carboxylate, bis (3,4-epoxy-) Alicyclic epoxies such as 6-methylcyclohexylmethyl) adipate, dicyclopentadiene oxide, and bis (2,3-epoxycyclopentyl) ether can be mentioned, and as the melamine-based curing agent, hexamethylolmelamine and alkylated hexamethylol are used. Examples thereof include melamine, partially methylolated melamine or alkylated products thereof, tetramethylol benzoguanamine, alkylated tetramethylol benzoguanamine, partially methylolated benzoguanamine or alkylated products thereof.

In addition to the photosensitive composition of the present invention,
The addition of a curing aid for promoting thermal curing can complete the curing at a relatively low temperature and in a short time,
Further, it is preferable because the chemical resistance can be further improved.

The curing aid is not particularly limited as long as it has good storage stability and sufficient thermosetting property, and examples thereof include latent thermal acid generators and latent photoacid generators. Agents, polycarboxylic acid anhydrides, polycarboxylic acids, phenolic compounds, and imidazole compounds can be used. In particular, the latent thermal acid generator is effective in terms of storage stability, and also polyvalent carboxylic anhydride, polyvalent carboxylic acid,
Phenolic compounds are also effective. Specific examples of the thermal acid generator include organic halogen compounds and onium salts. Examples of the organic halogen compounds include trihalomethyl group-containing triazine compounds and oxadiazole compounds, and onium salts include allyldiazonium salts. ,
(Di) allyl iodonium salt, (di, tri) allyl sulfonium salt and the like can be mentioned. Further, carboxylic acid anhydrides include phthalic anhydride, trimellitic anhydride, pyromellitic dianhydride, benzophenone tetracarboxylic anhydride, etc. as aromatic, succinic anhydride as aliphatic,
Examples thereof include maleic anhydride, and examples of the alicyclic group include methyl nadic acid anhydride, hexahydrophthalic anhydride, tetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, methyltetrahydrophthalic anhydride and the like. Examples of the carboxylic acid include ring-opened products of the above acid anhydrides. Further, as the phenolic compound, (poly) hydroxybenzophenone, bis [(poly) hydroxyphenyl] sulfone, bis [(poly) hydroxyphenyl] sulfide,
Examples include bisphenol A and bisphenol F.

The photosensitive composition of the present invention comprises, as described above, an alkali-soluble resin, a 1,2-naphthoquinonediazide sulfonic acid ester as a photosensitizer, a tetrafunctional or more alicyclic epoxy curing agent as a heat curing agent, and a solvent. It is contained, and its combination is characteristic. That is, the alkali-soluble resin is a polymer having an aromatic ring component and a carboxylic acid at the same time, or a vinylphenol (co) polymer, a novolac resin or a partially hydrogenated product of each resin, or a resin obtained by modifying a part of the hydroxyl groups of each resin. By using it, a system which is soluble in alkali, has a large refractive index, and is excellent in transparency can be realized. Moreover, it is characterized by excellent heat resistance and light resistance, and no change in transparency.

By using 1,2-naphthoquinonediazide sulfonic acid ester as a photosensitizer and mixing it with the above-mentioned alkali-soluble resin, a high-resolution resist which does not swell in an alkali developing solution can be realized. Further, a tetrafunctional or higher functional cycloaliphatic epoxy curing agent as a heat curing agent is necessary for imparting heat resistance, chemical resistance and good fluidity. In particular,
Since the heat curing can be performed at the same time when the lens is formed, it is very advantageous in the process.

In the photosensitive composition of the present invention, the composition ratio of the resin to the photosensitizer and the thermosetting agent can be variously changed within the range in which the characteristics can be maintained, but for example, the following range is preferable. . The photosensitizer is preferably 10 to 30% by weight based on the resin, and the thermosetting agent is 5 to 30% by weight based on the solid content. Within this range, the adhesiveness, transparency, sensitivity, resolution, and lens forming ability are excellent and stable characteristics can be exhibited.

The photosensitive composition of the present invention comprises, for example, a resin,
It is obtained by dissolving a photosensitizer and a thermosetting agent in an appropriate solvent so that the solid content is 10 to 40 parts by weight. As a solvent,
For example, ethylene glycol monoalkyl ether or its acetates, propylene glycol monoalkyl ether or its acetates, diethylene glycol mono or dialkyl ethers, alkyl propionate or its alkoxys, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone and other ketones, acetic acid Examples thereof include acetic acid esters such as ethyl and butyl acetate, aromatic hydrocarbons such as toluene and xylene, ethyl lactate, diacetone alcohol, dimethylacetamide, dimethylformamide, and N-methylpyrrolidone. These solvents can be used alone or in combination of two or more.

If necessary, in order to improve the coating property, a nonionic, fluorine-based or silicon-based surfactant may be added. Furthermore, if necessary, other compatible additives may be added.

The photosensitive composition of the present invention can be used for forming a resist pattern by ultraviolet rays, far ultraviolet rays, electron beams, X-rays, etc., and has excellent sensitivity and resolution. In particular, by performing a baking process after pattern formation,
A condenser lens can be formed. The formed lens has a large refractive index and is excellent in transparency, heat resistance, and chemical resistance.

The method of using the photosensitive composition of the present invention to form a resist pattern by irradiation with radiation is not particularly limited and may be a conventional method. Further, the lens pattern can be obtained by performing a heat treatment after forming the resist pattern.

For example, first, in the photosensitive resin solution, the alkali-soluble resin of the present invention, the photosensitizer and the thermosetting agent are dissolved in a solvent, and the insoluble matter is removed by filtration (for example, with a filter having a pore size of about 0.2 μm). It is prepared by
A photosensitive resin film is obtained by spin-coating a photosensitive resin solution on a substrate such as a silicon wafer or a resin hard-baked on a silicon wafer and pre-baking. Then, a resist pattern can be formed by performing exposure with a reduction projection exposure device, a proximity aligner, a mirror projection, an electron beam exposure device, etc., and developing and rinsing. Examples of the developer include sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, an inorganic alkaline aqueous solution such as ammonia, a primary amine such as ethylamine and n-propylamine, diethylamine, di-n-butylamine. Secondary amines such as triethylamine, tertiary amines such as methyldiethylamine, alcohol amines such as dimethylethanolamine and triethanolamine, and organic alkaline aqueous solutions such as tetramethylammonium hydroxide, tetraethylammonium hydroxide and choline. it can. Furthermore, alcohols and surfactants may be added in appropriate amounts to the above alkaline aqueous solution before use. Other techniques such as coating, baking, exposure, development, and rinsing can follow conventional methods for forming resist patterns for manufacturing integrated circuits and the like.

The resist pattern can be formed as described above. Next, for the lens pattern, the formed resist pattern is first exposed to UV light over the entire surface to impart transparency, and then 100 to 200 ° C., preferably 130 to 18 on a hot plate or in a convection oven.
It can be formed by heat treatment at a predetermined temperature of 0 ° C. for a predetermined time of about 1 to 30 minutes. The shape and curvature of the lens can be arbitrarily selected depending on the setting conditions.

[0040]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto.

Example 1 Styrene / maleic anhydride copolymerized partial ester (copolymerization ratio 2/1, weight average molecular weight 5000 (GPC measured value,
Polystyrene conversion), manufactured by Atochem Inc., SMA (trademark) -2625) 25 g, 2,3,4-
1,2-naphthoquinonediazide sulfonic acid ester of trihydroxybenzophenone (triester form) 6.0
g, 4-functional alicyclic epoxy resin (manufactured by Daicel Chemical Industries,
4.0 g of Epolide (trademark) GT-400 and 65 g of diethylene glycol dimethyl ether were mixed and dissolved, and then filtered with a 0.2 μm filter to prepare a resist solution.

Next, a resist solution having a thickness of 2.0 μm was formed by spin coating a resist solution on a silicon substrate, and
Prebaking was performed on a hot plate at 0 ° C. for 90 seconds. After that, a g-line reduction projection exposure apparatus (DSW-6300
A, GCA), and developed with a 1.2% tetramethylammonium hydroxide aqueous solution. The patterning could resolve 0.8 μmL / S at 400 mJ / cm ² .

Next, the obtained 6 μmL / S pattern is U-shaped.
Full exposure with V light (PLA-501, Canon) (L
After performing I = 30), it was heated on a hot plate at 160 ° C. for 10 minutes to flow and cure simultaneously to form a lens pattern. After forming the lens pattern, 200 ℃
No deformation of the pattern was observed even when the heat treatment was carried out at.

The refractive index of the lens pattern was 1.57, which was a good value as a lens material.

The transparency of the lens pattern in the visible light region was good, and was 97% at 400 nm, for example. No change in transparency was observed even after heating at 200 ° C.

Chemical resistance is water, isopropyl alcohol,
When it was dipped in a solvent of xylene or methyl ethyl ketone, no surface roughness was observed. In addition, the samples heated at 200 ° C. for 1 hour showed no change in resistance to mineral acids such as nitric acid and hydrochloric acid. Furthermore, 250
Good chemical resistance even in samples heated at ℃ for 1 hour,
No heat shrinkage or pattern deformation was observed, and it was confirmed that the heat resistance was extremely high.

Example 2 To the resist solution of Example 1, 0.2 g of benzyl-p-hydroxyphenylmethylsulfonium hexafluoroantimonate (curing aid, Sanshin Chemical Co., SI-100) was further added to form a resist. It was a solution.

Next, patterning and lens formation were carried out in the same manner as in Example 1. When developed with a 1.0% tetramethylammonium hydroxide aqueous solution, 6
It was possible to resolve 0.8 μm at 00 mJ / cm ² . The curing conditions were 140 ° C./3 minutes (hot plate), and the lens shape at that time was also good.
The chemical resistance was also good.

Example 3 25 g of vinylphenol / methylmethacrylate copolymer (copolymerization ratio 1/1, weight average molecular weight 9000 (GPC measurement value, polystyrene conversion)), 1,2 of 2,3,4-trihydroxybenzophenone -Naphthoquinone diazide sulfonic acid ester (triester) 6.0 g, polyfunctional alicyclic epoxy resin (manufactured by Daicel Chemical Industries, Cyclomer (trademark) M-100 polymer, weight average molecular weight 50)
3.0 g (measured by GPC, calculated as polystyrene) and 90 g of diethylene glycol dimethyl ether were mixed and dissolved, and then filtered through a 0.2 μm filter to prepare a resist solution.

Next, patterning and lens formation were performed by the same method as in Example 1. When developed with a 2.0% aqueous solution of tetramethylammonium hydroxide, 6
It was possible to resolve 0.8 μm at 00 mJ / cm ² . Curing conditions: 160 ° C / 10 minutes (hot plate)
The lens shape at that time was also good. The chemical resistance was also good.

Example 4 To the resist solution of Example 3, 1.0 g of 4,4'-bis (4-hydroxyphenyl) sulfone (curing aid) was further added to obtain a resist solution.

Next, patterning and lens formation were performed by the same method as in Example 1. When developed with a 2.0% tetramethylammonium hydroxide aqueous solution, 5
It was possible to resolve 0.7 μm at 00 mJ / cm ² . The curing conditions were 150 ° C./5 minutes (hot plate), and the lens shape at that time was also good.
The chemical resistance was also good.

Example 5 Styrene / methacrylic acid copolymer (copolymerization ratio 75/2
5, weight average molecular weight 6000 (GPC measured value, converted to polystyrene) 25 g, methyl gallate 1,2-naphthoquinonediazide sulfonate (triester form)
6.0 g, a multifunctional alicyclic epoxy resin (manufactured by Daicel Chemical Industries, Cyclomer (trademark) M-100 polymer, weight average molecular weight 5000 (GPC measured value, converted to polystyrene)) 3.0 g and diethylene glycol dimethyl ether 90 g were mixed. After the dissolution, the solution was filtered with a 0.2 μm filter to prepare a resist solution.

Next, patterning and lens formation were performed by the same method as in Example 1. When developed with a 0.5% tetramethylammonium hydroxide aqueous solution, 3
It was possible to resolve 0.8 μm at 00 mJ / cm ² . Curing conditions: 160 ° C / 10 minutes (hot plate)
The lens shape at that time was also good. The chemical resistance was also good.

Example 6 0.2 g of benzyl-p-hydroxyphenylmethylsulfonium hexafluoroantimonate (curing aid, Sanshin Chemical Co., SI-100) was added to the resist solution of Example 5 to form a resist. It was a solution.

Next, patterning and lens formation were performed by the same method as in Example 1. When developed with a 0.4% tetramethylammonium hydroxide aqueous solution, 5
It was possible to resolve 0.8 μm at 00 mJ / cm ² . The curing conditions were 140 ° C./5 minutes (hot plate), and the lens shape at that time was also good.
The chemical resistance was also good.

Comparative Example 1 The same resist solution as in Example 1 was used except that the thermosetting agent (tetrafunctional alicyclic epoxy resin) was not added.
The same method was repeated. It was possible to form a lens, but when heated at 200 ° C., the pattern flowed and the shape of the lens could not be maintained. Regarding the chemical resistance, for example, it was dissolved when immersed in methyl ethyl ketone.

Comparative Example 2 The same resist as in Example 1 except that the thermosetting agent (tetrafunctional alicyclic epoxy resin) was changed to a bifunctional alicyclic epoxy resin (Ceroxide (trademark) 2021 manufactured by Daicel Chemical Industries, Ltd.). The same procedure as in Example 1 was repeated using the solution. It was possible to form a lens sufficiently, but when heated at 200 ° C., the pattern slightly flowed and the shape of the lens changed. Regarding chemical resistance, for example, swelling of 0.5 μm was observed when immersed in methyl ethyl ketone. Further, when heat treatment was performed at 250 ° C., deformation of the lens pattern due to thermal contraction was observed.

Comparative Example 3 The same as Example 1 except that the thermosetting agent (tetrafunctional alicyclic epoxy resin) was changed to a trifunctional alicyclic epoxy resin (manufactured by DAICEL CHEMICAL INDUSTRIES, EPOLIDE (trademark) GT-300). The same procedure as in Example 1 was repeated using the resist solution in Example 1. Lens formation was sufficiently possible, and no pattern flow was observed even when heated at 200 ° C. However, in terms of chemical resistance, for example, nitric acid is 2
0.3μ even for samples that were treated at 00 ° C for 1 hour
Swelling of m was observed.

[0060]

As is clear from the above description, in the present invention, a photosensitizer comprising an alkali-soluble resin, 1,2-naphthoquinonediazide sulfonic acid ester, a tetrafunctional or higher alicyclic epoxy thermosetting agent, and Since the positive photosensitive composition containing a solvent is used, a highly sensitive and high-resolution resist pattern can be formed, and an uneven pattern having a lens function can be formed by heat treatment after patterning. The formed lens has a large refractive index, and has excellent properties such as transparency in the visible light range, heat resistance, light resistance, and chemical resistance, so that it can be used in color solid-state image pickup devices, color liquid crystal display devices, etc. It is suitable as a micro condenser lens material formed on a color filter. Further, since it also has a heat resistance of 250 ° C., it can be used as, for example, a reflection plate or an interlayer insulating film for a thin film magnetic head using a cured uneven pattern.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location C08G 59/40 NJM G02B 3/00 8106-2K G03C 1/695 9413-2H G03F 7/004 503 7 / 022 7/039

Claims (5)

[Claims] 1. An alkali-soluble resin, 1, as a photosensitizer
A photosensitive composition for forming a microlens, comprising a 2-naphthoquinonediazide sulfonate, a tetrafunctional or higher functional alicyclic epoxy compound as a heat curing agent, and a solvent. 2. The alkali-soluble resin is represented by the following general formula (1):
Alternatively, the photosensitive composition for forming a microlens according to claim 1, comprising a structural unit represented by the general formula (2). [Chemical 1] [In the formula, R ₁ represents hydrogen or a methyl group, A is OA ₁ or NA ₂ A ₃ (A ₁ , A ₂ and A ₃ are hydrogen and carbon atoms are 1 respectively.
And an alkyl group having 6 to 6 carbon atoms, an allyl group having 6 to 12 carbon atoms, or an aralkyl group having 7 to 12 carbon atoms. ), K and m each represent an integer of 1 or more, and l and n each represent an integer including 0. ] [Chemical 2] [In the formula, R ₁ represents hydrogen or a methyl group, R ₂ and R ₃ represent hydrogen, a methyl group, chlorine or bromine, respectively, and A is O
A ₁ or NA ₂ A ₃ (A ₁ , A ₂ and A ₃ are hydrogen, an alkyl group having 1 to 6 carbon atoms, an allyl group having 6 to 12 carbon atoms or an aralkyl group having 7 to 12 carbon atoms, respectively. Is shown), x and y represent an integer including 0, and z represents an integer of 1 or more. ] 3. An alkali-soluble resin is a vinylphenol polymer, a vinylphenol copolymer, a novolak resin which is a polycondensation product of phenols and aldehydes, a partial hydrogenation product of each resin, or a part of the hydroxyl groups of each resin. The photosensitive composition for forming a microlens according to claim 1, wherein the photosensitive composition is a resin modified from. 4. A photosensitive composition for microlens formation, which further comprises a curing aid in the photosensitive composition for microlens formation according to any one of claims 1 to 3. 5. The curing aid according to claim 4, wherein the curing aid is at least one selected from a latent thermal acid generator, a polycarboxylic acid anhydride, a polycarboxylic acid, and a phenol compound. A photosensitive composition for forming a microlens.