JPH0798503A - Thermosetting positive type photosensitive composition - Google Patents

Abstract

PURPOSE:To provide a photosensitive compsn. having satisfactory appliability on a stepped part and used at the time of producing a solid-state image pickup element, a liq. crystal element, etc. CONSTITUTION:This photosensitive compsn. for a stepped substrate consists of an alkali-soluble resin, a photosensitive agent, a heat curing agent and a solvent based on a mixture of a solvent selected from among alkyl lactate, alkyl alkoxypropionate, propylene glycol monoalkyl et.her and propylene glycol monoalkyl ether acetate with a ketone solvent having <=150 deg.C b.p.

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 the purpose of utilizing a microlens-shaped uneven pattern and a heat-cured uneven pattern. Means that there is no precipitation of the photosensitive component in the photosensitive composition,
The present invention relates to a thermosetting positive photosensitive composition which has excellent storage stability and can impart high flatness when applied to a stepped substrate having irregularities.

[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 an improvement in the sensitivity of the element and a reduction in aliasing distortion of the output signal of the element, and formation of a micro condensing lens is an essential condition of the 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 device as described in JP-A-4-243226, JP-A-5-34730 or the like or an interlayer for a thin film magnetic head described in JP-A-4-63351 or the like. Patterning of insulating film,
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.
-189604, JP-A-3-282403, JP-A-3-223702, JP-A-4-182650, JP-A-4-352101, and JP-A-5-158232, the surface protection of a transparent photosensitive resin is carried out. It can be formed by coating on the film, exposing and developing so that the resin layer remains in the portion corresponding to the photodiode, and then heat treating the pattern.

[0006]

By the way, the performance of the image pickup device 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. Further, it is important to form a lens that is uniform in the plane. In particular, with the recent miniaturization of photodiodes, a higher-resolution resist function and smooth coatability on a concave-convex substrate for improving in-plane uniformity are required.

[0007] In general, as a method for achieving high resolution of a positive photoresist, a method of increasing the esterification rate of a quinonediazide-containing compound as a photosensitizer has been tried. The problem in that case is that the solubility of the photosensitizer in a solvent is lowered, and as a result, precipitation of the photosensitive component is caused during storage of the solution. Various solvents have been studied as measures for improving the problem.

Conventionally, ethylene glycol ethyl ether acetate has been generally used as a solvent for photoresists, but its use is being prohibited due to toxicity with diethylene glycol dimethyl ether. Further, as a novel solvent in consideration of solubility and safety, cyclopentanone (JP-A-59-155838), monooxymonocarboxylic acid ester (Japanese Patent Publication No. 3-22619)
No.), propylene glycol alkyl ether acetate (Japanese Patent Publication No. 3-1659, Japanese Patent Publication No. 4-56973).
No.), propylene glycol monoalkyl ether (Japanese Patent Publication No. 3-6494), propylene glycol alkyl ether acetate and propylene glycol monoalkyl ether mixed solvent (Japanese Patent Publication No. 4-59630), cyclic ketone and alcohol mixed solvent (USP4526856).
No.), 3-methyl-3-methoxybutylacetate (JP-A-1-62359), dicarboxylic acid diester (JP-A-1-173029), isopropyl cellosolve acetate (JP-A-1-293341), glycol diester (JP-A-1-293341). 2-84649), 3-methoxybutanol (JP-A-4-9064), 3-methyl-3-.
Methoxybutanol (JP-A-4-9852), alkyl pyruvate (JP-A-4-36752), alkyl lactate acetate (JP-A-4-368863), trialkyl orthoformate (JP-A-4-368949), propionic acid. n-Butyl, n-ethyl valerate, n-propyl n-butyrate (JP-A-4-368950), mixed solvent of acetic acid ester and alkyl pyruvate (JP-A-5-94013)
No.) etc. have been proposed.

The above remedy is a description in the case of a photoresist using a novolak resin as an alkali-soluble resin and naphthoquinonediazide as a photosensitizer. In the case of a thermosetting positive-type photosensitive composition, the resin, the photosensitizer, and the thermosetting agent have their respective characteristics, and therefore the solubility in a solvent in the case of the conventionally proposed photoresist is different. Moreover, in order to improve the in-plane uniformity, smooth coating properties on the uneven substrate, especially when used as a micro-focusing lens, the product value will be lost if the focusing efficiency decreases a little. Properties are required, and at present, satisfactory properties cannot be obtained with the above coating solvents. Further, the above-mentioned publicly known documents do not mention the smooth coating property of a composition containing a resin, a photosensitizer and a thermosetting agent on an uneven substrate.

In general, when an organic substance is spin-coated, it is very difficult to form a uniform coating film by completely flattening a substrate having irregularities, and it is common for unevenness of the film thickness to occur due to irregularities of the base. Is. The case of forming a micro condensing lens is no exception, and the demand for flatness has become stronger, especially under the recent demands for miniaturization and strict dimensional accuracy. Some improvements are expected due to changes in the resin content concentration or changes in the coating environment, but drastic improvements cannot be expected, and in light of future trends, it is necessary to review from the viewpoint of materials.

Therefore, it can be said at present that there is a strong demand for a photosensitive composition having good coating properties on uneven steps.

The present invention has been made in view of the above problems, and an object thereof is that the photosensitive component is not deposited and the coatability on a step having unevenness is very good.
Provided is a photosensitive composition which can be used for a micro solid-state lens material formed on a color filter such as a color solid-state image pickup device and a color liquid crystal display device, and a microlens-like uneven pattern and a heat-cured uneven pattern. To do.

[0013]

Means for Solving the Problems As a result of intensive studies on coating solvents in order to solve the above problems, the present inventors have found a solvent system capable of solving the above problems and completed the present invention. It is a thing. That is, the present invention is a photosensitizer comprising an alkali-soluble resin, a 1,2-naphthoquinonediazide sulfonate as a photosensitizer, a thermosetting agent that imparts heat resistance and chemical resistance by heat treatment after patterning as a thermosetting agent, and a solvent. In the sexual composition,
The main component of the solvent is a mixture of one solvent selected from alkyl lactate, alkoxypropionic acid alkyl ester, propylene glycol monoalkyl ether or propylene glycol monoalkyl ether acetate, and a ketone solvent having a boiling point of 150 ° C. or lower. It is a thermosetting positive-type photosensitive composition characterized by the above.

The present invention will be described in more detail below.

The thermosetting positive photosensitive composition of the present invention comprises
It is composed of an alkali-soluble resin, a photosensitizer which is 1,2-naphthoquinonediazide sulfonate, a thermosetting agent and a solvent, and is characterized by using a special combination of solvents. That is, the main component of the solvent is lactate alkyl ester, alkoxypropionate alkyl ester,
It is an organic compound composed of a mixture of one kind of solvent selected from propylene glycol monoalkyl ether or propylene glycol monoalkyl ether acetate and a ketone solvent having a boiling point of 150 ° C. or lower. Specifically, as the alkyl lactate, methyl lactate, ethyl lactate,
Butyl lactate and the like, alkyl propionate alkyl esters such as methyl 3-methoxypropionate and ethyl 3-ethoxypropionate, and propylene glycol monoalkyl ethers such as propylene glycol monomethyl ether and propylene glycol monoethyl ether. Examples of the propylene glycol monoalkyl ether acetate include acetic acid ester of propylene glycol monoalkyl ether. In addition, examples of the ketone solvent having a boiling point of 150 ° C. or lower include acetone, methyl ethyl ketone, diethyl ketone, methyl-n-propyl ketone, methyl-n-butyl ketone, methyl isobutyl ketone, di-n-propyl ketone, and the like.

The feature of the combination of both solvents in the present invention is to make up for the drawbacks of a single solvent. Specifically, it can be summarized as follows, although it is different depending on the combination. In the case of ketone-based solvents, lower ketones with a short carbon number cause uneven coating on flat substrates, which is called striation, and the coating properties are extremely poor on uneven substrates.In addition, higher ketones dissolve resins and photosensitizers. It becomes poor in property and it is impossible to prepare a solution with a single solvent. On the other hand, in the case of an alkyl lactate ester, the solubility is good, but the coating uniformity on unevenness is difficult due to its high viscosity. In the case of the alkoxypropionic acid alkyl ester, propylene glycol monoalkyl ether, and propylene glycol monoalkyl ether acetate, there is no solvent that can sufficiently satisfy both the coating property and the solubility on unevenness. Therefore, in the case of the mixed solvent, the combination of the individual solvents which can supplement the coating property or the solubility on the insufficient unevenness can maximize the effects of the present invention. Further, the mixing of a ketone solvent having a boiling point of 150 ° C. or lower has an effect of lowering the viscosity of the solution, an effect of increasing the evaporation rate, an effect of increasing the spreadability of the solution at the time of application, etc. It is possible to improve the property.

The mixing ratio of both solvents is not particularly limited as long as the above characteristics are satisfied, and the optimum mixing ratio depends on the combination of the alkali-soluble resin, the photosensitizer and the thermosetting agent. Generally, the ratio of lactic acid alkyl ester, alkoxypropionic acid alkyl ester, propylene glycol monoalkyl ether, propylene glycol monoalkyl ether acetate and ketone solvent is in the range of 1: 9 to 9: 1. Is.

The following solvents may be added to the solvent in the present invention to the extent that the characteristics are not impaired.
For example, ethylene glycol monoalkyl ether and its acetates, diethylene glycol mono- or dialkyl ethers, pyruvic acid alkyl esters, ethyl acetate, acetic acid esters such as butyl acetate, toluene,
Examples thereof include aromatic hydrocarbons such as xylene, alcohols such as methanol and ethanol, diacetone alcohol, dimethylacetamide, dimethylformamide, N-methylpyrrolidone and γ-butyrolactone. If necessary, a nonionic, fluorine-based, or silicon-based surfactant or other compatible additive may be added.

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.

[0020]

[Chemical 4]

[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. ]

[0022]

[Chemical 5]

[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 each represent an integer including 0, and z represents an integer of 1 or more. ] The alkyl group represented by A _{1 to} A ₃ in the above formula is a methyl group,
Examples thereof include ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, t-butyl group, n-amyl group, isoamyl group, n-hexyl group and cyclohexyl group, and the allyl group is phenyl. Group, tolyl group, xylyl group, ethylphenyl group, naphthyl group, etc., aralkyl group includes benzyl group, phenethyl group, etc., benzene ring is halogen such as chlorine, bromine, nitro group, cyano group, etc. It may be substituted.

As the alkali-soluble resin, 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 hydroxyl group of each resin is used. 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) is (α-methyl) styrene / (meth) acrylic acid or (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 a copolymerization component of the vinylphenol copolymer, a monomer having a double bond capable of radical copolymerization can be used, and examples thereof include methyl acrylate, methyl methacrylate, hydroxyethyl methacrylate, glycidyl methacrylate and the like. Examples thereof include (meth) acrylic 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 used in the present invention is not particularly limited as long as it does not deteriorate the properties, and examples thereof include melamine compounds, phenol compounds, azo compounds, isocyanate compounds, epoxy compounds, Examples include functionally unsaturated compounds. A melamine-based compound or an epoxy-based compound represented by the following general formula (3) is preferable because of its excellent properties.

[0032]

[Chemical 6]

[In the formula, W represents --NY ₅ Y ₆ {Y ₅ and Y ₆ are each hydrogen or --CH ₂ OZ (Z represents hydrogen or an alkyl group having 1 to 6 carbon atoms). } Or a phenyl group, and Y ₁ to Y ₄ are each hydrogen or —CH ₂ O.
Z (Z represents hydrogen or an alkyl group having 1 to 6 carbon atoms). ] In addition, as the alkyl group of Z in the above general formula, a methyl group, an ethyl group, an n-propyl group,
Examples thereof include isopropyl group, n-butyl group, isobutyl group, t-butyl group, n-amyl group, isoamyl group, n-hexyl group and cyclohexyl group.

Examples of the melamine compound include hexamethylolmelamine and alkylated hexamethylolmelamine, partially methylolated melamine and alkylated products thereof, tetramethylolbenzoguanamine and alkylated tetramethylolbenzoguanamine, partially methylolated benzoguanamine and alkylated products thereof. Etc. On the other hand, as the epoxy-based compound, for example, as a glycidyl ether type, n-butyl glycidyl ether, 2-ethoxyhexyl glycidyl ether, phenyl glycidyl ether, allyl glycidyl ether, ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, neo Examples thereof include pentyl glycol diglycidyl ether, glycerol polyglycidyl ether, and sorbitol polyglycidyl ether. Examples of the glycidyl ester type include adipic acid diglycidyl ester and o-phthalic acid diglycidyl ester, and alicyclic epoxy type. Is 3,4-epoxycyclohexylmethyl (3,4
-Epoxycyclohexane) carboxylate, 3,4
-Epoxy-6-methylcyclohexylmethyl (3,4
-Epoxy-6-methylcyclohexane) carboxylate, bis (3,4-epoxy-6-methylcyclohexylmethyl) adipate, dicyclopentadiene oxide, bis (2,3-epoxycyclopentyl) ether, polyfunctional alicyclic epoxy resin (Eporide (trademark) G
Examples thereof include T-300 and GT-400 (manufactured by Daicel Chemical Industries).

When a melamine compound and an epoxy compound are mixed and used as the thermosetting agent, the above compounds may be used in an appropriate combination.

Further, other thermosetting agents such as isocyanate-based ones may be used as long as the properties of these compounds are not deteriorated.
You may add a polyfunctional unsaturated compound etc.

The addition of a curing aid for accelerating heat curing to the positive photosensitive composition of the present invention can complete the curing at a relatively low temperature in a short time, and 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, imidazole compounds and the like.

Examples of the latent acid generator include organic halogen compounds and onium salts, and examples of the organic halogen compounds include trihalomethyl group-containing triazine compounds and oxadiazole compounds, and onium salts. , Allyldiazonium salts, (di) allyliodonium salts, (di, tri) allylsulfonium salts and the like.

As the polyvalent carboxylic acid anhydride, for example,
Aliphatic acid anhydrides such as polyadipic acid anhydride, polyazelaic acid anhydride, polysebacic acid anhydride, poly (ethyloctadecanedioic acid) anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, methylhymic anhydride Alicyclic acid anhydrides such as acids, hexahydrophthalic anhydride, tetrahydrophthalic anhydride, trialkyltetrahydrophthalic anhydride, methylcyclohexene dicarboxylic acid anhydride, phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, benzophenone tricarboxylic acid Examples thereof include acid anhydrides, benzophenone tetracarboxylic acid anhydrides, aromatic acid anhydrides such as ethylene glycol bistrimellitate and glycerol tris trimellitate, and halogen-based acid anhydrides such as het anhydride and tetrabromophthalic anhydride.

Examples of the polyvalent carboxylic acid include aliphatic acid anhydrides, alicyclic acid anhydrides, aromatic acid anhydrides, hydrolysates of halogen-based acid anhydrides, succinic acid, glutaric acid, adipic acid, Butanetetracarboxylic acid, maleic acid, malonic acid, itaconic acid, 1,2,4-cyclohexanetricarboxylic acid, cyclopentanetetracarboxylic acid, 1,4
Examples include 5,8-naphthalene tetracarboxylic acid.

Examples of the imidazole compound include 2
-Methylimidazole, 2-ethyl-4-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 2-phenylimidazole, 1-benzyl-2-methylimidazole, 1-cyanoethyl-2
-Methylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-undecylimidazolium trimellitate, 2-methylimidazolium isocyanurate, 2 -Phenylimidazolium isocyanurate, 2,4-diamino-6-
[2-Methylimidazolyl- (1)]-ethyl-s-triazine, 2,4-diamino-6- [2-ethylimidazolyl- (1)]-ethyl-s-triazine, 2,4-
Diamino-6- [2-undecylimidazolyl-
(1)]-Ethyl-s-triazine, 2-phenyl-
Examples include 4,5-dihydroxymethylimidazole, 1-cyanoethyl-2-phenyl-4,5-di (cyanoethoxymethyl) imidazole and the like.

The solid content concentration of the positive photosensitive composition of the present invention is not particularly limited as long as the solubility can be sufficiently maintained, but normally the resin, the photosensitizer and the thermosetting agent are all solids. It can be used by dissolving it in a solvent so that the content becomes 10 to 50% by weight.

In the positive photosensitive composition of the present invention,
The composition ratio of the resin to the photosensitizer and the resin to the thermosetting agent can be variously changed within a range in which the characteristics can be maintained.
For example, the thermosetting agent is preferably 5 to 30% by weight based on the solid content, and the photosensitizer is 10 to 30% by weight based on the solid content.
Within this range, in addition to flatness, adhesion, transparency,
It is possible to maintain a stable system with good heat resistance, chemical resistance, resist function and lens characteristics due to curing.

The positive photosensitive composition of the present invention contains an alkali-soluble resin, a 1,2-naphthoquinonediazide sulfonic acid ester as a photosensitizer, a thermosetting agent and a solvent as described above. That is, the resin is a polymer having an aromatic ring component and a carboxylic acid at the same time, a vinylphenol (co) polymer, a novolac resin, a partially hydrogenated product of each resin, or a resin obtained by partially modifying the hydroxyl groups of each resin. A system that is soluble in alkali, has a large refractive index, and has good 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, the thermosetting agent is necessary for imparting heat resistance and chemical resistance. In particular, heat curing can be performed simultaneously with lens formation, which is extremely advantageous in the process.

The most characteristic feature of the positive-working photosensitive composition of the present invention lies in the combination of solvents, from alkyl lactate esters, alkoxypropionic acid alkyl esters, propylene glycol monoalkyl ethers or propylene glycol monoalkyl ether acetates. The above component is dissolved in a mixed solvent of one selected solvent and a ketone solvent having a boiling point of 150 ° C. or less. In the solvent system, the characteristics of each component of the alkali-soluble resin, the photosensitizer, and the thermosetting agent can be maximized, and there is no precipitation of the photosensitive component in the photosensitive composition, which is excellent in storage stability.
In addition, a pattern with further improved in-plane uniformity can be formed in order to impart a high degree of flatness when applied to a stepped substrate having irregularities, and as a result, a micro-focusing lens having exactly the same shape can be formed. .

The positive type photosensitive composition of the present invention can be exposed to ultraviolet rays, deep ultraviolet rays, electron beams, X-rays and the like to form a resist pattern, and is excellent in sensitivity and resolution. In particular, a thermosetting micro-condensing lens or a concavo-convex pattern is formed by performing a baking process after forming the pattern. The formed lens has a uniform shape, a large refractive index, and excellent transparency, heat resistance, and chemical resistance.

The method of using the positive 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. The heat-cured lens pattern or uneven pattern can be obtained by performing heat treatment after forming a resist pattern.

For example, first, in the photosensitive resin solution, an alkali-soluble resin, a photosensitizer and a thermosetting agent are dissolved in the mixed solvent of the present invention, and the insoluble matter is removed by filtration (for example, with a filter having a pore size of about 0.2 μm). Prepared by removing. 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. When forming a thermosetting concave-convex pattern that does not require transparency, the entire surface exposure with UV light can be omitted.

[0052]

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 After forming a photoresist pattern by photolithography on a silicon substrate on which a silicon dioxide film having a thickness of 1 μm was formed, the silicon dioxide film was etched by a reactive ion etching method using a resist pattern as a mask. Finally, the photoresist was removed, and irregularities of 10 μm and 5 μm line / space (L / S) of silicon dioxide were formed on the silicon substrate.

P-Vinylphenol / Methyl Methacrylate Copolymer (Maruzen Petrochemical, Maruka Linker ™)
CMM, weight average molecular weight 8500 (polystyrene conversion), copolymerization ratio 1/1) 25 g, methyl gallate 1,
6.5 g of 2-naphthoquinonediazide-5-sulfonic acid ester (triester), hexamethoxymethylol melamine (manufactured by Mitsui Cyanamid, Cymel (trademark))
-303) 4.5 g, fluorine-based surfactant (Sumitomo Three M
Fluorinert (trademark) FC-430) 0.04 g,
108 g of ethyl lactate and 12 g of acetone were mixed and dissolved, and then filtered with a 0.2 μm filter to prepare a resist solution.

This resist solution was spin-coated on a substrate having irregularities to a thickness of 2.0 μm, and the temperature was 90 ° C./9.
Bake on a hot plate for 0 seconds. After that, when the flatness of the flattening film was observed using a contact type step measuring device (Taylor Hobson Co., Taristep (trademark)), no unevenness was observed on the inner and outer peripheries of the substrate on the flattening film. It was completely flattened.

Next, 2.0 μm is formed on the flat silicon substrate.
After coating the resist solution in a thick thickness and baking on a hot plate at 90 ° C. for 90 seconds, a g-line reduction projection exposure apparatus (G
It was exposed through a reticle with DSW-6300A (CA, CA) and developed with a 1.3% aqueous solution of tetramethylammonium hydroxide. Patterning is 250 mJ / cm ²
Was able to resolve 0.8 μmL / S.

Next, the obtained 6 μmL / S pattern is U-shaped.
After performing overall exposure (LI = 30) with V light (PLA-501 manufactured by Canon Inc.), 130, 140, 150,
It heated for 5 minutes on each hot plate of 160 degreeC.
It was possible to create lens patterns with various curvatures according to each temperature. Also, after forming the lens pattern, 200 ° C
No deformation of the pattern was observed even when the heat treatment was carried out at. Furthermore, chemical resistance is water, isopropyl alcohol,
When it was immersed in a solvent such as trichloroethane, xylene, or methyl ethyl ketone, no surface roughness was observed. When the storage stability of the resist solution was measured by a foreign matter inspection (automatic liquid particle counter, manufactured by Rion), the number of foreign matter of 1.0 μm or more was 1 in the initial stage and 1 in 2 months later, and deposition of the photosensitive component. Was not recognized.

Example 2 25 g of styrene / maleic anhydride copolymerized half-benzyl ester (copolymerization ratio 2/1, weight average molecular weight 8500 (in terms of polystyrene)), 2,3,4,4'-tetrahydroxybenzophenone 1 , 2-naphthoquinonediazide-
5-sulfonic acid ester (3.5 ester form) 6.0
g, hexabutoxymethylol melamine (Mitsui Cyanamid, Mycoat (trademark) -506) 4.0 g, fluorine-based surfactant (Sumitomo Three M, Fluorinert (trademark) FC-430) 0.04 g, ethyl lactate 84 g and After mixing and dissolving 36 g of methyl isobutyl ketone,
A resist solution was prepared by filtering with a 2 μm filter.

This resist solution was applied onto a stepped substrate similar to that in Example 1 by spin coating so as to have a thickness of 2.0 μm.
Bake at 90 ° C./90 seconds on a hot plate. Then, when the flatness was observed in the same manner as in Example 1, no unevenness was recognized on the flattening film on the inner and outer peripheries of the substrate, and the flattening was extremely complete.

After that, an exposure test was conducted in the same manner as in Example 1 except that a 0.5% tetramethylammonium hydroxide aqueous solution was used as the developing solution. as a result,
Patterning is 0.8 μmL / S at 300 mJ / cm ^2.
Was able to be resolved.

Next, the obtained 6 μmL / S pattern was used for U
After performing overall exposure (LI = 30) with V light (PLA-501 manufactured by Canon Inc.), 130, 140, 150,
It heated for 5 minutes on each hot plate of 160 degreeC.
It was possible to create lens patterns with various curvatures according to each temperature. Also, after forming the lens pattern, 200 ° C
No deformation of the pattern was observed even when the heat treatment was carried out at. Furthermore, chemical resistance is water, isopropyl alcohol,
When it was immersed in a solvent such as trichloroethane or xylene, no surface roughness was observed. When the storage stability of the resist solution was measured by a foreign matter inspection, precipitation of a photosensitive component after 2 months was not observed.

Example 3 25 g of polyvinylphenol (Maruzen Petrochemical, Maruka Linker (trademark) M, weight average molecular weight 9600 (in terms of polystyrene)), 1,2-naphthoquinonediazide-5-sulfonate of methyl gallate (tri Ester) 6.5 g, tetrafunctional alicyclic epoxy resin (manufactured by Daicel Chemical Industries, Epolide (trademark) GT-400) 6.0
g, 0.04 g of a fluorine-based surfactant (Sumitomo Three M, Fluorinert (trademark) FC-430), 117 g of propylene glycol monomethyl ether and 13 g of methyl ethyl ketone were mixed and dissolved, and then filtered with a 0.2 μm filter to form a resist. A solution was prepared.

This resist solution was applied by spin coating onto a stepped substrate similar to that in Example 1 to a thickness of 2.0 μm, and 90
Bake at 90 ° C./90 seconds on a hot plate. Then, when the flatness was observed in the same manner as in Example 1, no unevenness was recognized on the flattening film on the inner and outer peripheries of the substrate, and the flattening was extremely complete.

Then, an exposure test was conducted in the same manner as in Example 1 except that a 0.7% tetramethylammonium hydroxide aqueous solution was used as the developing solution. as a result,
Patterning is 0.8 μmL / S at 700 mJ / cm ^2.
Was able to be resolved.

Next, the obtained 6 μmL / S pattern was
It heated on each hot plate of 130, 140, 150, 160 degreeC for 5 minutes each. It was possible to create thermosetting uneven patterns having various curvatures according to each temperature. In addition, after the thermosetting pattern was formed, the pattern was not deformed even if heat treatment was performed at 200 ° C. Further, regarding chemical resistance, no surface roughness was observed when immersed in a solvent such as water, isopropyl alcohol, trichloroethane, xylene or methyl ethyl ketone.

Example 4 p-Vinylphenol / methylmethacrylate copolymer (Maruzen Petrochemical, Marca Linker (trademark) CMM, weight average molecular weight 8500 (polystyrene conversion), copolymerization ratio 1/1) 25 g, gallic acid 3. 1,2-naphthoquinonediazide-5-sulfonic acid ester of methyl (triester form) 6.5 g, hexamethoxymethylol melamine (manufactured by Mitsui Cyanamid, Cymel (trademark) -303) 4.
5 g, fluorosurfactant (Sumitomo Three M, Fluorinate (trademark) FC-430) 0.04 g, methyl 3-methoxypropionate 99 g and methyl ethyl ketone 11 g
Were mixed and dissolved, and then filtered through a 0.2 μm filter to prepare a resist solution.

This resist solution was applied by spin coating on a stepped substrate similar to that in Example 1 to a thickness of 2.0 μm, and 90
Bake at 90 ° C./90 seconds on a hot plate. Then, when the flatness was observed in the same manner as in Example 1, no unevenness was recognized on the flattening film on the inner and outer peripheries of the substrate, and the flattening was extremely complete.

Then, an exposure test was conducted in the same manner as in Example 1 except that a 1.3% tetramethylammonium hydroxide aqueous solution was used as the developing solution. as a result,
Patterning is 230 μJ / cm ² and 0.8 μmL / S
Was able to be resolved.

Next, the obtained 6 μmL / S pattern was used as U
After performing overall exposure (LI = 30) with V light (PLA-501 manufactured by Canon Inc.), 130, 140, 150,
It heated for 5 minutes on each hot plate of 160 degreeC.
It was possible to create lens patterns with various curvatures according to each temperature. Also, after forming the lens pattern, 200 ° C
No deformation of the pattern was observed even when the heat treatment was carried out at. Furthermore, chemical resistance is water, isopropyl alcohol,
When it was immersed in a solvent such as trichloroethane, xylene, or methyl ethyl ketone, no surface roughness was observed. When the storage stability of the resist solution was measured by a foreign matter inspection, precipitation of a photosensitive component after 2 months was not observed.

Example 5 Styrene / maleic anhydride copolymerized half-benzyl ester compound (copolymerization ratio 2/1, weight average molecular weight 8500 (in terms of polystyrene)) 25 g, 2,3,4,4'-tetrahydroxybenzophenone 1 , 2-naphthoquinonediazide-
5-sulfonic acid ester (3.5 ester form) 6.0
g, hexabutoxymethylol melamine (Mitsui Cyanamid, Mycoat (trademark) -506) 4.0 g, fluorine-based surfactant (Sumitomo Three M, Fluorinert (trademark) FC-430) 0.04 g, propylene glycol ethyl ether 102 g of acetate and 18 g of methyl ethyl ketone were mixed and dissolved, and then filtered with a 0.2 μm filter to prepare a resist solution.

This resist solution was applied by spin coating on a stepped substrate similar to that in Example 1 to a thickness of 2.0 μm, and 90
Bake at 90 ° C./90 seconds on a hot plate. Then, when the flatness was observed in the same manner as in Example 1, no unevenness was recognized on the flattening film on the inner and outer peripheries of the substrate, and the flattening was extremely complete.

Then, an exposure test was conducted in the same manner as in Example 1 except that a 0.5% tetramethylammonium hydroxide aqueous solution was used as the developing solution. as a result,
Patterning is 0.8 μmL / S at 350 mJ / cm ^2.
Was able to be resolved.

Next, the obtained 6 μmL / S pattern is U-shaped.
After performing overall exposure (LI = 30) with V light (PLA-501 manufactured by Canon Inc.), 130, 140, 150,
It heated for 5 minutes on each hot plate of 160 degreeC.
It was possible to create lens patterns with various curvatures according to each temperature. Also, after forming the lens pattern, 200 ° C
No deformation of the pattern was observed even when the heat treatment was carried out at. Furthermore, chemical resistance is water, isopropyl alcohol,
When it was immersed in a solvent such as trichloroethane or xylene, no surface roughness was observed. When the storage stability of the resist solution was measured by a foreign matter inspection, precipitation of a photosensitive component after 2 months was not observed.

Comparative Example 1 A resist solution was prepared by changing the solvent of Example 1 to ethyl lactate alone. By spin coating, the same stepped substrate as in Example 1 was coated to a thickness of 2.0 μm and baked on a hot plate at 90 ° C. for 90 seconds. After that, when the flatness was observed in the same manner as in Example 1, no unevenness was observed on the inner peripheral portion of the substrate on the flattening film, and the surface was completely flattened, but the outer peripheral portion had unevenness of about 0.2 μm. Was recognized.

Comparative Example 2 A resist solution was prepared by changing the solvent of Example 3 to propylene glycol monomethyl ether alone. By spin coating, the same stepped substrate as in Example 1 was coated to a thickness of 2.0 μm and baked on a hot plate at 90 ° C. for 90 seconds. After that, when the flatness was observed in the same manner as in Example 1, no unevenness was recognized on the flattening film on both the inner and outer circumferences of the substrate,
It was extremely flattened.

However, when the storage stability of the resist solution was measured by a foreign matter inspection, the number of foreign matter of 1.0 μm or more was 2 in the initial stage and 150 after 2 months, and deposition of the photosensitive component was recognized.

Comparative Example 3 A resist solution was prepared by changing the solvent of Example 4 to methyl 3-methoxypropionate alone. By spin coating,
The same step as in Example 1 was applied to a stepped substrate to a thickness of 2.0 μm,
Bake at 90 ° C./90 seconds on a hot plate. After that, when the flatness was observed in the same manner as in Example 1, no unevenness was observed on the inner peripheral portion of the substrate on the flattening film, and the surface was completely flattened, but the outer peripheral portion had unevenness of about 0.2 μm. Was recognized.

Comparative Example 4 A resist solution was prepared by changing the solvent of Example 5 to propylene glycol ethyl ether acetate alone. By spin coating, 2.0 μ is formed on the stepped substrate similar to that in the first embodiment.
It was applied to a thickness of m and baked on a hot plate at 90 ° C./90 seconds. After that, when the flatness was observed in the same manner as in Example 1, unevenness of 0.1 μm was recognized on the flattening film on the inner peripheral portion of the substrate, and unevenness of about 0.3 μm was recognized on the outer peripheral portion.

Comparative Example 5 A resist solution was prepared by changing the solvent of Example 2 to methyl isobutyl ketone alone. Example 1 by spin coating
Same as above, but apply it to a 2.0 μm thick stepped substrate at 90 ° C /
Bake for 90 seconds on a hot plate. After that, when the flatness was observed in the same manner as in Example 1, radial unevenness due to striation was severe, and it was in a state where it could not be determined whether the unevenness was good or bad.

[0080]

As is apparent from the above description, in the present invention, a lactate alkyl ester, an alkoxypropionic acid alkyl ester, a propylene glycol monoalkyl ether or a propylene glycol monoalkyl which has suitable polarity, evaporation rate and viscosity together. Since a thermosetting positive photosensitive composition using a mixed solvent of one solvent selected from ether acetate and a ketone solvent having a boiling point of 150 ° C. or less as a coating solvent is used, it is excellent in storage stability of a resist solution. The coating property on the step is good, and the uneven base can be highly planarized. As a result, when a lens or a thermosetting concave-convex pattern is formed after forming a pattern having excellent sensitivity and resolution, it is possible to realize a highly reliable and finer and more uniform shape.

Since the thermosetting positive-type photosensitive composition of the present invention has the above-mentioned excellent properties, it can be used for manufacturing a solid-state image pickup device, a micro focusing lens for a liquid crystal display device, a reflector plate, and a thin film magnetic head. It can be preferably used as a photosensitive composition used for coating and processing on a substrate having irregularities.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location G03F 7/023 511

Claims (3)

[Claims] 1. An alkali-soluble resin, 1, as a photosensitizer
In a thermosetting positive photosensitive composition comprising a 2-naphthoquinone diazide sulfonate, a thermosetting agent that imparts heat resistance and chemical resistance by heat treatment after patterning as a thermosetting agent, and a solvent, the main component of the solvent is A heat characterized by being a mixture of one solvent selected from alkyl lactate, alkoxypropionic acid alkyl ester, propylene glycol monoalkyl ether or propylene glycol monoalkyl ether acetate and a ketone solvent having a boiling point of 150 ° C. or lower. Curing positive type photosensitive composition. 2. A novolak-based resin in which the alkali-soluble resin is a vinylphenol polymer, a vinylphenol copolymer, a polycondensation product of phenols and aldehydes, a partial hydrogenation product of each resin, or a hydroxyl group of each resin. The thermosetting positive photosensitive composition according to claim 1, which is a resin having a modified part or a resin comprising a structural unit represented by the following general formula (1) or 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 each represent an integer including 0, and z represents an integer of 1 or more. ] 3. The heat-curing agent according to claim 1, wherein the heat-curing agent is selected from at least one selected from a curing agent having a structural unit represented by the following general formula (3) or an epoxy-based curing agent. Positive type photosensitive composition. [Chemical 3] [In the formula, W represents —NY ₅ Y ₆ {Y ₅ and Y ₆ each represent hydrogen or —CH ₂ OZ (Z represents hydrogen or an alkyl group having 1 to 6 carbon atoms). } Or a phenyl group, and Y
₁ to Y ₄ each represent hydrogen or —CH ₂ OZ (Z represents hydrogen or an alkyl group having 1 to 6 carbon atoms). ]