JP4789727B2 - Photosensitive resin composition, laminate thereof, cured product thereof, and pattern forming method using the composition - Google Patents

Description

  The present invention relates to a photosensitive resin composition capable of forming a pattern having a high resolution and a high aspect ratio, a laminate thereof, a cured product thereof, and a pattern forming method using the composition.

  Photolithographic processable resists have recently been widely used in semiconductor and MEMS (microelectromechanical systems) applications. In such an application, photolithography processing is performed by patterning exposure on a substrate, and then it is achieved by selectively removing exposed or non-exposed areas by developing with a developer. Resist that can be processed by photolithography (photoresist) has a positive type or a negative type. A resist that dissolves in a developer upon exposure is a positive type, and a resist that becomes insoluble is a negative type. Advanced electro-package applications require high aspect ratios, while MEMS applications maintain a uniform spin coating film formation capability, maintain a straight shape with a thickness of 100 μm or more, and enable photolithography with a high aspect ratio Resist is required. Here, the aspect ratio is an important characteristic expressed by resist film thickness / pattern line width and showing the performance of photolithography.

  Conventional positive resists based on the dinaphthoquinone-novolak reaction are not suitable for applications requiring thick films of 50 μm or more. There is a limit in increasing the film thickness because the dinaphthoquinone type (DNQ) photoreactant in the near-ultraviolet region wavelength (350 to 450) generally used for resist exposure has a relatively high light absorption. . In the DNQ type photoresist, the side wall shape is not a straight shape but a slope shape due to a characteristic solubility difference between the exposed region and the non-exposed region in the developer. Light absorption reduces the irradiation intensity from the top to the bottom of the film, but if this light absorption is too high, the bottom of the resist will be underexposed compared to the top, resulting in a slope shape or a distorted shape. Become.

  Negative type chemically amplified thick film photolithography processable compositions are known to have very low light absorption in the 350-450 nm wavelength region, and the composition of this resist is multifunctional bisphenol A novolac epoxy resin ( Photocationic polymerization initiators such as EPON SU-8 resin manufactured by Resolution Performance Products and CYRACURE UVI-6974 manufactured by Dow Chemical (This photocationic polymerization initiator is propylene carbonate of aromatic sulfonium hexafluoroantimonate. Consisting of solution). This photoresist composition is spin-coated or curtain-coated on various substrates, and then the solvent is volatilized by baking to form a solid photoresist layer having a thickness of 100 μm or more. Further, contact exposure, proximity exposure, Photolithography is performed by irradiating near ultraviolet light through a photomask using various exposure methods such as projection exposure. Then, it is immersed in a developing solution, the non-exposed area is dissolved, and a high-resolution photomask negative image is formed on the substrate.

  EPON SU-8 resin is a low molecular weight epoxy oligomer that has superior features in high aspect ratio photolithography processing with thick films. Its advantageous features are (1) high epoxy functional group number, (2) high branching degree, (3) high transmittance at 350-450 nm, and (4) low molecular weight necessary and sufficient to form solids. is there. High epoxy functional group number and high degree of branching cause sufficient cross-linking under strong acid catalyst, and high transmittance is uniformly irradiated through a thick film, and resist performance to form a pattern with an aspect ratio of 10 or more with a thick film of 100μ or more have. The selection of a resin having a high number of epoxy functional groups and a high degree of branching is an important item for forming a structure having a high aspect ratio with straight sidewalls. The selection of a low molecular weight resin allows a thick film photoresist to form a solid layer on the substrate with a minimum number of coating steps.

  Photocationic polymerization initiators based on sulfonium salts or iodonium salts are well known, and useful photocationic polymerization initiators with moderate absorbance are disclosed, including carbonyl-p-phenylenethioether ( Patent Documents 1 and 2). Further, it is possible to add a sensitizer such as 2-alkyl-9,10-dimethoxyanthracene or other anthracene, naphthalene, peryl or pyryl compound, which may be introduced into the photocationic polymerization initiator (Patent Document). 3).

  Negative resists based on the above disclosed compounds suitable for spin coating are marketed by Micro Chem and are used commercially, especially in MEMS device components. For example, the “SU-8 Series” provided by Micro-Chem Company is spin-coated at 1000 to 3000 rpm to form a film with a thickness of 30 to 100 μm, and after exposure and development, an aspect ratio with a film thickness of 100 μ or more. Ten or more patterns can be formed.

  An application such as a dry film resist coated on a substrate such as a polyester film is also disclosed (Patent Document 4).

  A photoimageable cationic polymerizable flame retardant composition suitable for use as a solder mask is disclosed (Patent Documents 5, 6, and 7). This consists of a mixture containing 10-80% by weight of a condensate of bisphenol A and epichlorohydrin, 20-90% by weight of bisphenol A novolac epoxy resin, 35-50% by weight of epoxidized tetrabromobisphenol A, and photocationic polymerization. It consists of a composition containing 0.1 to 15% by weight of an initiator.

  A photopolymerizable compound based on a hydroxyl group-containing additive, a photocationic polymerization initiator, and an epoxy resin having a functional group number of 1.5 or more is also disclosed. Hydroxyl-containing additives have been reported to increase flexibility and reduce stress in thick films of 100 μm or more (Patent Document 8).

  Patent Document 9 discloses a method of making a hard epoxy resin system in an EB curable application. The main improvement here is the brittleness of the radiation-cured epoxy resin. Many structural and consumer resins (epoxy resins) must have sufficient strength and impact resistance to withstand years of rigorous service. A wide range of tough materials including SU-8 resin is disclosed herein. For increased strength, the effectiveness of the claimed invention is demonstrated by fracture toughness and flexural modulus. The tough materials within the scope of the claims consist of various thermoplastics, hydroxyl-containing thermoplastic oligomers, epoxy-containing thermoplastic oligomers, reactive softeners, elastomers, rubbers and mixtures thereof. However, the composition described in Patent Document 9 is a composition applied to a film imaged by non-pattern EB irradiation. When patterned and exposed by UV, X-ray and EB irradiation, the properties of these compositions are not useful for photo imaging applications.

Many proposals have been made on photoresist compositions containing epoxy (Patent Document 10). Here, the necessity of formulating a resist composition as applied to, for example, a spin coating method is disclosed, and rheological characteristics are required. In addition, the composition here needs to have a sufficient transmittance for exposure irradiation that photodegrades the photoinitiator through the film thickness. In order to withstand various applications, the photoresist composition must have appropriate physical and chemical properties such that there is no solder resistance or ink resistance or strength, significant deterioration, or poor adhesion. If this photoresist composition is used for other applications, such as an etching photoresist, other properties are required. There is currently no specific epoxy resin that satisfies all of the various requirements. Many different combinations or mixtures of various epoxy resins have already been disclosed, and all of the prominent patents describe various resins, photoinitiators for photocuring compositions, many of which are permanent film applications It will be useful as a photoimageable resist. However, none of these disclose the optimal composition for our intended MEMS application, and in fact most examples of plasticizers, softeners and tougheners reduce lithographic performance.
USP5502083 USP 6368769 B1 USP 5102772 USP 4882245 USP 5026624 USP 5278010 USP 5304457 USP 4256828 USP 5726216 USP 5264325

  In the conventional photosensitive resin composition using a polyfunctional epoxy resin such as a novolak-type epoxy resin, the sensitivity of the photocation polymerization initiator contained is low, so that it is necessary to contain a large amount of initiator or a short amount of initiator. There was a problem that the mask pattern could not be faithfully reproduced in time. Moreover, although the photocationic polymerization initiator containing SbF6- has a relatively high sensitivity, there has been a problem that its intended use is limited due to toxicity problems.

  The present invention has been made in view of the above-described conventional circumstances, and the problem is to provide a photosensitive resin composition that can form a pattern with high resolution and a high aspect ratio and has high sensitivity. is there.

In order to solve the above-mentioned problems, the present inventors have intensively studied, experimented, and studied on increasing the sensitivity and resolution of the photosensitive resin composition, and as a result, a specific polyfunctional epoxy resin and a specific photocation were obtained. It was found that if a photosensitive resin composition was prepared in combination with a polymerization initiator and a resin pattern was formed using this photosensitive resin composition, a resin pattern with high sensitivity and high aspect ratio could be formed. . That is, the present invention
(1) 1,2-epoxy-4- (2-oxiranyl ) of photocationic polymerization initiator (A) which is sulfonium tris (pentafluoroethyl) trifluorophosphate and 2,2-bis (hydroxymethyl) -1-butanol ) A photosensitive resin composition containing the cyclohexane adduct (B),
(2) The photocationic polymerization initiator (A) described in (1) above is a compound (A-1) represented by the following formula (1):

A photosensitive resin composition, wherein
( 3 ) In the photosensitive resin composition containing the solvent (D), the solid content concentration is 5 to 95% by weight, the photosensitive resin composition according to the above (1) or (2) ,
( 4 ) The radiation-sensitive composition according to any one of the above (1) to ( 3 ), wherein the main chain structure of the polyfunctional epoxy compound has a branched alkylene chain ( 5 ) The above (1) to ( 4 ) A photosensitive resin composition laminate in which the photosensitive resin composition according to ( 4 ) is sandwiched between substrates, ( 6 ) a cured product of the photosensitive resin composition according to (1) to ( 5 ) above,
( 7 ) The photosensitive resin composition according to any one of (1) to ( 4 ) above is applied on a desired support, dried, and then exposed to a predetermined pattern to expose the photosensitive resin composition layer. Post-baking, developing the resin composition layer, and heat-treating the obtained resin pattern to obtain a cured resin pattern having a predetermined shape,
( 8 ) The substrate of the laminate described in ( 5 ) above is removed, and the substrate is attached onto the desired support, the photosensitive resin composition layer is exposed to a predetermined pattern, post-exposure baking is performed, and the resin composition Developing a product, heat-treating the obtained resin pattern to obtain a cured resin pattern of a predetermined shape,
About.

(Mode for carrying out the invention)
Hereinafter, embodiments of the present invention will be described.
The photosensitive resin composition of the present invention comprises a photocationic polymerization initiator (A) that is a salt of sulfonium with tris (pentafluoroethyl) trifluorophosphate ion, an alicyclic structure in the main chain structure, and an epoxy group. It contains three or more polyfunctional epoxy compounds (B), and can form a resin pattern with high sensitivity and high aspect ratio. Furthermore, the characteristic which can be exhibited over a long period of time can be provided, without the capability to form the said resin pattern deteriorating. These combinations can be various, but in particular, as a polyfunctional epoxy compound, for example, the main chain structure such as XD-1000 (manufactured by Nippon Kayaku Co., Ltd.) has an alicyclic structure and the epoxy group has 3 or more polyfunctional epoxy compounds; an alicyclic structure and a branched alkylene chain in the main chain structure such as Epolide GT300, Epolide GT400, EHPE3150 (manufactured by Daicel Chemical Industries, Ltd.), and 3 or more epoxy groups A combination of a polyfunctional epoxy compound and a photocationic polymerization initiator that is a compound represented by the formula (2) is most preferable.

  The cationic photopolymerization initiator in the present invention generates cations upon irradiation with radiation such as excimer lasers such as ultraviolet rays, far ultraviolet rays, KrF and ArF, X-rays, and electron beams, and the cations can serve as polymerization initiators. A compound.

  The cationic photopolymerization initiator (A) is a salt of sulfonium with tris (pentafluoroethyl) trifluorophosphate ion.

  As the sulfonium of the cationic photopolymerization initiator, triphenylsulfonium, tri-p-tolylsulfonium, tri-o-tolylsulfonium, tris (4-methoxyphenyl) sulfonium, 1-naphthyldiphenylsulfonium, 2-naphthyldiphenylsulfonium, Tris (4-fluorophenyl) sulfonium, tri-1-naphthylsulfonium, tri-2-naphthylsulfonium, tris (4-hydroxyphenyl) sulfonium, 4- (phenylthio) phenyldiphenylsulfonium, 4- (p-tolylthio) phenyldi- p-tolylsulfonium, 4- (4-methoxyphenylthio) phenylbis (4-methoxyphenyl) sulfonium, 4- (phenylthio) phenylbis (4-fluorophenyl) sulfonium, -(Phenylthio) phenylbis (4-methoxyphenyl) sulfonium, 4- (phenylthio) phenyldi-p-tolylsulfonium, bis [4- (diphenylsulfonio) phenyl] sulfide, bis [4- (bis [4- (2 -Hydroxyethoxy) phenyl] sulfonio) phenyl] sulfide, bis (4- [bis (4-fluorophenyl) sulfonio] phenyl) sulfide, bis (4- [bis (4-methylphenyl) sulfonio] phenyl) sulfide, bis ( 4- [bis (4-methoxyphenyl) sulfonio] phenyl) sulfide, 4- (4-benzoyl-4-chlorophenylthio) phenylbis (4-fluorophenyl) sulfonium, 4- (4-benzoyl-4-chlorophenylthio) Phenyldiphenylsulfonium 4- (4-benzoylphenylthio) phenylbis (4-fluorophenyl) sulfonium, 4- (4-benzoylphenylthio) phenyldiphenylsulfonium, 4-isopropyl-4-oxo-10-thia-9,10-dihydroanthracene 2-yldi-p-tolylsulfonium, 7-isopropyl-9-oxo-10-thia-9,10-dihydroanthracen-2-yldiphenylsulfonium, 2-[(di-p-tolyl) sulfonio] thioxanthone, 2 -[(Diphenyl) sulfonio] thioxanthone, 4- [4- (4-tert-butylbenzoyl) phenylthio] phenyldi-p-tolylsulfonium, 4- [4- (4-tert-butylbenzoyl) phenylthio] phenyldiphenylsulfonium, 4- [4- (Ben Zoylphenylthio)] phenyldi-p-tolylsulfonium, 4- [4- (benzoylphenylthio)] phenyldiphenylsulfonium, 5- (4-methoxyphenyl) thiaanthrhenium, 5-phenylthiaanthrhenium, 5-tolylthia Triarylsulfonium such as anthrenium, 5- (4-ethoxyphenyl) thiaanthrhenium, 5- (2,4,6-trimethylphenyl) thiaanthrhenium; diphenylphenacylsulfonium, diphenyl-4-nitrophenacylsulfonium, diphenyl Diarylsulfonium such as benzylsulfonium, diphenylmethylsulfonium; phenylmethylbenzylsulfonium, 4-hydroxyphenylmethylbenzylsulfonium, 4-methoxyphenylmethylbenzylsulfur 4-acetocarbonyloxyphenylmethylbenzylsulfonium, 2-naphthylmethylbenzylsulfonium, 2-naphthylmethyl (1-ethoxycarbonyl) ethylsulfonium, phenylmethylphenacylsulfonium, 4-hydroxyphenylmethylphenacylsulfonium, 4-methoxy Monoarylsulfonium such as phenylmethylphenacylsulfonium, 4-acetocarbonyloxyphenylmethylphenacylsulfonium, 2-naphthylmethylphenacylsulfonium, 2-naphthyloctadecylphenacylsulfonium, 9-anthracenylmethylphenacylsulfonium; dimethylphena Silsulfonium, phenacyltetrahydrothiophenium, dimethylbenzylsulfonium, benzyltetrahydride Thiophenium, etc. trialkyl sulfonium such as octadecyl methyl phenacyl sulfonium and the like, which are described in the following documents.

  Regarding triarylsulfonium, U.S. Pat. No. 4,231,951, U.S. Pat. No. 4,256,828, JP-A-7-61964, JP-A-8-165290, JP-A-7-10914, JP-A-7-25922, JP-A-8- 27208, JP-A-8-27209, JP-A-8-165290, JP-A-8-301991, JP-A-9-143212, JP-A-9-278813, JP-A-10-7680, JP-A-10-287463. JP-A-10-245378, JP-A-8-157510, JP-A-10-204083, JP-A-8-245656, JP-A-8-157451, JP-A-7-324069, JP-A-9-268205. JP, 9-278935, JP 2001-288205, JP 11-80118, JP 10-182825, JP-A-10-330353, JP-A-10-152495, JP-A-5-239213, JP-A-7-333834, JP-A-9-12537, JP-A-8-325259, JP-A-8. -160606, JP-A No. 2000-186071 (US Pat. No. 6,368,769), etc .; Regarding diarylsulfonium, JP-A Nos. 7-300504, 64-45357, 64-64419, etc .; monoaryl Regarding sulfonium, JP-A-6-345726, JP-A-8-325225, JP-A-9-118663 (US Pat. No. 6,097,753), JP-A-2-196812, JP-A-2-1470, JP-A-2-1470 196812, JP-A-3-237107, JP-A-3-17101, JP-A-6- 28086, JP-A-10-152469, JP-A-7-300505, JP-A-2003-277353, JP-A-2003-277352, etc .; with respect to trialkylsulfonium, JP-A-4-308563, JP-A-5-140210, JP-A-5-140209, JP-A-5-230189, JP-A-6-271532, JP-A-58-37003, JP-A-2-178303, JP-A-10-338688, JP-A-9-328506, JP-A-11-228534, JP-A-8-27102, JP-A-7-333834, JP-A-5-222167, JP-A-11-21307, JP-A-11-35613, US Pat. It is done.

  In particular, as the sulfonium of the photocationic polymerization initiator, triphenylsulfonium and 4- (phenylthio) phenyldiphenylsulfonium are more preferable, and 4- (phenylthio) phenyldiphenylsulfonium (A-1) represented by the following formula (3) is preferable. Most preferred.

  The polyfunctional epoxy compound (B) having an alicyclic structure in the main chain structure and having 3 or more epoxy groups in the present invention contains sufficient epoxy groups in one molecule to form a thick film pattern. Any epoxy resin may be used as long as it is a polyfunctional epoxy resin. The epoxy equivalent of these polyfunctional epoxy resins is preferably 150 to 400, and if it is smaller than this range, the curing shrinkage is large. On the other hand, if it is larger than this range, the crosslinking density is undesirably small. A polyfunctional epoxy compound having an alicyclic structure in the main chain structure such as XD-1000 (manufactured by Nippon Kayaku Co., Ltd.) satisfying the above-mentioned range and having 3 or more epoxy groups; Kogyo Co., Ltd.) is particularly preferred.

  If the polyfunctional epoxy compound having an alicyclic structure in the main chain structure and having 3 or more epoxy groups has a low softening point, mask sticking is likely to occur during patterning, and it can be used as a dry film resist. It is not preferable because it softens at room temperature. On the other hand, when the polyfunctional epoxy compound having an alicyclic structure in the main chain structure and having 3 or more epoxy groups has a high softening point, it is difficult to soften when laminating the dry film resist to the substrate, Since pasting property worsens, it is not preferable. For the above reasons, the preferred softening point of the polyfunctional epoxy resin is 40 to 120 ° C, more preferably 50 to 100 ° C.

  The content of the photocationic polymerization initiator (A) in the photosensitive resin composition is too high, the main chain structure has an alicyclic structure, and the polyfunctional epoxy compound (B) has 3 or more epoxy groups. When the content in the photosensitive resin composition is too low, it is not preferable because development of the resin composition is difficult and a film after curing becomes brittle. Conversely, the content of the photocationic polymerization initiator (A) in the photosensitive resin composition is too low, the polyfunctional epoxy compound having an alicyclic structure in the main chain structure and 3 or more epoxy groups ( When the content of B) in the photosensitive resin composition is too high, the curing time by radiation exposure of the resin composition becomes long when coated on the substrate, which is not preferable. Considering these, the ratio of the photocationic polymerization initiator (A) to the polyfunctional epoxy compound (B) having an alicyclic structure in the main chain structure and having 3 or more epoxy groups is 0.1: 99.9. -15: 85, preferably 0.5: 99.5-10: 90.

  In order to further improve the performance of the pattern, a miscible reactive epoxy monomer (C) may be added to the photosensitive resin composition of the present invention. As the reactive epoxy monomer, a glycidyl ether compound can be used, for example, diethylene glycol diglycidyl ether, hexanediol diglycidyl ether, dimethylolpropane diglycidyl ether, polypropylene glycol diglycidyl ether (manufactured by Asahi Denka Kogyo Co., Ltd., ED506), Examples thereof include trimethylolpropane triglycidyl ether (manufactured by Asahi Denka Kogyo Co., Ltd., ED505), pentaerythritol tetraglycidyl ether, and the like. These can be used alone or in admixture of two or more. The reactive epoxy monomer (C) component is used for the purpose of improving the reactivity of the resist and the physical properties of the cured film. However, the reactive epoxy monomer component is often in a liquid form, and when the component is in a liquid form, it is 20% by weight. If it is added in an amount greater than%, it is inappropriate because the film after solvent removal tends to be sticky and mask sticking is likely to occur. From this point, when blending the monomer component, the blending ratio is 1 to the total solid content of the resist, with the total of the (A) component, (B) component, and (C) component being the solid content of the resist. 10% by weight is preferable, and 2 to 7% by weight is particularly preferable.

  A solvent (D) can be used to lower the viscosity of the photosensitive resin composition of the present invention and improve the coating properties. As the solvent, any organic solvent that can dissolve each component can be used. Examples of such organic solvents include ketones such as acetone, ethyl methyl ketone, and cyclohexanone, aromatic hydrocarbons such as toluene, xylene, and tetramethylbenzene, glycol ethers such as dipropylene glycol dimethyl ether and dipropylene glycol diethyl ether, Ethyl acetate, butyl acetate, butyl cellosolve acetate, carbitol acetate, propylene glycol monomethyl ether acetate, esters such as γ-butyrolactone, alcohols such as methanol, ethanol, ceresolve, methyl ceresolve, aliphatic hydrocarbons such as octane, decane And organic solvents such as petroleum solvents such as petroleum ether, petroleum naphtha, hydrogenated petroleum naphtha, and solvent naphtha.

  These solvents can be used alone or in admixture of two or more. The solvent component is added for the purpose of adjusting the film thickness and applicability when applied to a substrate, and in order to maintain the solubility of the main component, the volatility of the component, and the liquid viscosity of the composition properly. The amount is preferably 5 to 95% by weight, particularly preferably 10 to 90% by weight, based on the photosensitive resin composition.

  In the photosensitive resin composition of the present invention, a miscible adhesion imparting agent may be used for the purpose of further improving the adhesion of the composition to the substrate. As the adhesion-imparting agent, a coupling agent such as a coupling agent silane coupling agent or a titanium coupling agent can be used, and a silane coupling agent is preferable.

  Examples of the silane coupling agent include 3-chloropropyltrimethoxysilane, vinyltrichlorosilane, vinyltriethoxysilane, vinyltrimethoxysilane, vinyl tris (2-methoxyethoxy) silane, 3-methacryloxypropyltrimethoxysilane, 2 -(3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-2- (aminoethyl) -3 -Aminopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, etc. are mentioned. These adhesiveness imparting agents can be used alone or in combination of two or more. Since the adhesion-imparting agent is non-reactive with the main component, components other than those that act at the substrate interface exist as residual components after curing, and if used in a large amount, adverse effects such as deterioration of physical properties will occur. Depending on the base material, it is suitable for use within a range that does not adversely affect the effect even in a small amount, and its use ratio is preferably 15% by weight or less, particularly preferably based on the photosensitive resin composition. Is 5% by weight or less.

  In the photosensitive resin composition of the present invention, a sensitizer may be further used for absorbing ultraviolet light and supplying the absorbed light energy to the photocationic polymerization initiator. As the sensitizer, for example, an anthracene compound having an alkoxy group at the 9-position and the 10-position (9,10-dialkoxyanthracene derivative) is preferable. As an alkoxy group, C1-C4 alkoxy groups, such as a methoxy group, an ethoxy group, a propoxy group, are mentioned, for example. The 9,10-dialkoxyanthracene derivative may further have a substituent. Examples of the substituent include halogen atoms such as fluorine atom, chlorine atom, bromine atom and iodine atom, C1-C4 alkyl group such as methyl group, ethyl group and propyl group, sulfonic acid alkyl ester group, and carboxylic acid alkyl ester group. Etc. Examples of the alkyl in the sulfonic acid alkyl ester group and the carboxylic acid alkyl ester include C1-C4 alkyl such as methyl, ethyl, and propyl. The substitution position of these substituents is preferably the 2-position.

  As the 9,10-dialkoxyanthracene derivative, for example, 9,10-dimethoxyanthracene, 9,10-diethoxyanthracene, 9,10-dipropoxyanthracene, 9,10-dimethoxy-2-ethylanthracene, 9,10- Diethoxy-2-ethylanthracene, 9,10-dipropoxy-2-ethylanthracene, 9,10-dimethoxy-2-chloroanthracene, 9,10-dimethoxyanthracene-2-sulfonic acid methyl ester, 9,10-diethoxyanthracene -2-sulfonic acid methyl ester, 9,10-dimethoxyanthracene-2-carboxylic acid methyl ester, and the like. These can be used alone or in admixture of two or more. Since the sensitizer component exerts its effect in a small amount, its use ratio is preferably 3% by weight or less, particularly preferably 1% by weight or less, relative to the photocationic polymerization initiator (A) component.

  In the present invention, when it is necessary to reduce the adverse effects of ions derived from the photocationic polymerization initiator (A), trismethoxyaluminum, trisethoxyaluminum, trisisopropoxyaluminum, isopropoxydiethoxyaluminum, trisbutoxyaluminum, etc. Alkoxyaluminum, Trisphenoxyaluminum, Trisparamethylphenoxyaluminum, etc. Phenoxyaluminum, Trisacetoxyaluminum, Trisstearatoaluminum, Trisbutyratoaluminum, Trispropionatoaluminum, Trisacetylacetonatoaluminum, Tristrifluoroacetylacetonatoaluminum , Trisethyl acetoaceto aluminum, diacetyl acetonato dipivaloyl methanato aluminum Um, diisopropoxy may be added ion catcher, such as (ethylacetoacetato) an organoaluminum compound, such as aluminum, these components may be used alone or in combination of two or more. Moreover, the compounding quantity is 10 weight% or less with respect to solid content.

  Furthermore, in this invention, various additives, such as a thermoplastic resin, a coloring agent, a thickener, an antifoamer, a leveling agent, can be used as needed. Examples of the thermoplastic resin include polyethersulfone, polystyrene, and polycarbonate. Examples of the colorant include phthalocyanine blue, phthalocyanine green, iodin green, crystal violet, titanium oxide, carbon black, and naphthalene black. Examples of the thickener include olben, benton, and montmorillonite. Examples of the antifoaming agent include antifoaming agents such as silicone-based, fluorine-based, and polymer-based, and these additives are used. In this case, the amount used is, for example, about 0.1 to 30% by weight in the photosensitive resin composition of the present invention, but may be appropriately increased or decreased depending on the purpose of use.

  In the present invention, inorganic fillers such as barium sulfate, barium titanate, silicon oxide, amorphous silica, talc, clay, magnesium carbonate, calcium carbonate, aluminum oxide, aluminum hydroxide, and mica powder are used. The blending ratio is 0 to 60% by weight in the composition.

  The photosensitive resin composition of the present invention is preferably blended in the proportions shown in Table 1 below, and if necessary, the adhesion imparting agent, sensitizer, ion catcher, thermoplastic resin, colorant, thickener, defoaming agent. Agents, leveling agents and inorganic fillers may be added. It is only necessary to mix and stir by a usual method, and if necessary, a disperser such as a dissolver, a homogenizer, or a three roll mill may be used for dispersion and mixing. Moreover, after mixing, you may further filter using a mesh, a membrane filter, etc.

  The photosensitive resin composition of the present invention is preferably used in liquid form. In order to use the photosensitive resin composition of the present invention, for example, it is coated on a substrate such as a silicon wafer or glass with a thickness of 0.1 to 1000 μm using a spin coater or the like, and at 60 to 130 ° C. for 5 to 60 minutes. After heat treatment to remove the solvent and form the photosensitive resin composition layer, a mask having a predetermined pattern is placed and irradiated with ultraviolet rays, and heat treatment is performed at 50 to 130 ° C. for about 1 to 50 minutes. After that, the unexposed part is developed with a developer at room temperature to 50 ° C. for about 1 to 180 minutes to form a pattern, and then subjected to heat treatment at 130 to 200 ° C., thereby providing permanent protection satisfying various characteristics. A membrane is obtained. As the developer, for example, an organic solvent such as γ-butyrolactone, triethylene glycol dimethyl ether, propylene glycol monomethyl ether acetate, or a mixed solution of the organic solvent and water can be used. For development, a paddle type, spray type, shower type, or other developing device may be used, and ultrasonic irradiation may be performed as necessary.

  The resin composition of the present invention is applied to the base film using a roll coater, die coater, knife coater, bar coater, gravure coater, etc., and then dried in a drying oven set at 45 to 100 ° C. A dry film resist can be obtained by removing a predetermined amount of the solvent and, if necessary, laminating a cover film or the like. At this time, the thickness of the resist on the base film is adjusted to 2 to 100 μm. As a base film and a cover film, films, such as polyester, a polypropylene, polyethylene, TAC, a polyimide, are used, for example. As these films, a film which has been subjected to a release treatment with a silicon release treatment agent or a non-silicon release treatment agent may be used as necessary. In order to use this dry film resist, for example, the cover film is peeled off, transferred to a substrate at a temperature of 40 ° C. to 100 ° C. at a pressure of 0.05 to 2 MPa by a hand roll, a laminator, and the like. Similar to the resin composition, exposure, post-exposure baking, development, and heat treatment may be performed.

  If the photosensitive resin composition is supplied as a film as described above, the steps of coating on the support and drying can be omitted, and the photosensitive resin composition of the present invention can be used more simply. Pattern formation is possible.

  The cured product of the resin composition of the present invention obtained by the above method is used, for example, as a permanent resist film, for example, for MEMS parts such as an inkjet recording head.

  Examples of the present invention will be described below. However, these examples are merely examples for suitably explaining the present invention, and do not limit the present invention.

Examples 1 to 4 (Comparative Examples 1 to 3)
(Photosensitive resin composition)
A photosensitive composition in which a polyfunctional epoxy resin, a photocationic polymerization initiator, and other components were mixed according to the composition described in the following table (unit: part by weight) was obtained.

(Patterning of photosensitive resin composition)
(Examples 1 to 3) (Comparative Examples 1 to 3)
This photosensitive resin composition was applied onto a silicon wafer with a spin coater and then dried to obtain a photosensitive resin composition layer having a thickness of 80 μm. This photosensitive resin composition layer was prebaked on a hot plate at 65 ° C. for 5 minutes and at 95 ° C. for 15 minutes. Thereafter, pattern exposure (soft contact, i-line) is performed using an i-line exposure apparatus (mask aligner: manufactured by Ushio Electric), post-exposure baking (PEB) is performed at 95 ° C. for 6 minutes using a hot plate, and propylene glycol Development processing was performed at 23 ° C. for 6 minutes by immersion using monomethyl ether acetate to obtain a resin pattern cured on the substrate.

(Evaluation of photosensitive resin composition)
After the development, the following evaluation was performed according to the required exposure amount. The results are shown in Table 2 below.

Optimum exposure amount: Exposure amount with the best mask transfer accuracy Aspect ratio: Film thickness / The finest pattern width closely adhered in the formed resist pattern

note:
(A-1): Photocationic polymerization initiator (trade name: CPI-210S manufactured by San Apro)
(B-1): Alicyclic polyfunctional epoxy compound (trade name EHPE3150, manufactured by Daicel Chemical Industries)
(B-2): Alicyclic polyfunctional epoxy compound (trade name GT300, manufactured by Daicel Chemical Industries)
(B-3): Alicyclic polyfunctional epoxy compound (trade name GT400, manufactured by Daicel Chemical Industries)
(C): Reactive epoxy monomer (trade name ED506 manufactured by Asahi Denka Kogyo Co., Ltd.)
(D-1): Solvent Cyclopentanone (D-2): Solvent MEK
(E): Fluorine-based leveling agent (trade name: MegaFuck F-470, manufactured by Dainippon Ink, Inc.)
(F): Silane coupling agent (trade name: S-510, manufactured by Chisso Corporation)
(G): Photocationic polymerization initiator (trade name: UVI-6974, 50% propylene carbonate solution manufactured by Dow Chemical Company)

  Examples 1-4 were good results as shown in the table.

Example 4
(Photosensitive resin composition)
100 parts by weight of an alicyclic polyfunctional epoxy resin (trade name EHPE3150 manufactured by Daicel Chemical Industries), 4.6 parts by weight of a cationic photopolymerization initiator (trade name CPI-210S manufactured by San Apro), reactive epoxy monomer (commodity) A photosensitive composition was obtained by mixing 4 parts by weight of ED506 manufactured by Asahi Denka Kogyo Co., Ltd. and 40 parts by weight of MEK.
(Patterning of photosensitive resin composition)
This photosensitive resin composition was uniformly applied onto a polypropylene (PP) film (base film, manufactured by Toray Industries, Inc.) having a film thickness of 60 μm, and dried at 65 ° C. for 10 minutes and at 80 ° C. for 15 minutes by a hot air convection dryer. Thereafter, a PP film (cover film) having a film thickness of 60 μm was laminated on the exposed surface to form a photosensitive resin composition laminate having a film thickness of 40 μm.

The cover film of the photosensitive resin composition laminate is peeled off and laminated on a silicon wafer at a roll temperature of 70 ° C., an air pressure of 0.2 MPa, and a speed of 0.5 m / min. This operation is further repeated once to obtain a thickness of 80 μm. The photosensitive resin composition layer was laminated. This photosensitive resin composition layer was subjected to pattern exposure (soft contact, i-line) using an i-line exposure apparatus (mask aligner: manufactured by Ushio Inc.). Then, PEB was performed for 4 minutes at 95 ° C. using a hot plate, and development processing was performed for 4 minutes at 23 ° C. by immersion using PGMEA to obtain a cured resin pattern on the substrate. An optimum exposure amount of 120 mJ / cm ² and an excellent aspect ratio of 7.4 were obtained.

  From the results of Examples 1 to 5, a combination of a specific polyfunctional epoxy resin and a specific photocationic polymerization initiator can provide a resin pattern with a high sensitivity and a high aspect profile that cannot be obtained by other combinations. I understood.

  As described above, the photosensitive resin composition according to the present invention is useful for forming a resin pattern having a high aspect profile, and is particularly suitable for resin molding with high dimensional stability in a fine size electronic device. Yes.

Claims (8)

Addition of 1,2-epoxy-4- (2-oxiranyl) cyclohexane between photocationic polymerization initiator (A) which is sulfonium tris (pentafluoroethyl) trifluorophosphate and 2,2-bis (hydroxymethyl) -1-butanol A photosensitive resin composition comprising the product (B). The photocationic polymerization initiator (A) according to claim 1 is a compound (A-1) represented by the following formula (1):

The photosensitive resin composition characterized by the above-mentioned. The photosensitive resin composition according to claim 1 or 2 , wherein the photosensitive resin composition containing the solvent (D) has a solid content concentration of 5 to 95% by weight. The radiation-sensitive composition according to any one of claims 1 to 3 , wherein the main chain structure of the polyfunctional epoxy compound has a branched alkylene chain. The photosensitive resin composition laminated body which pinched | interposed the photosensitive resin composition in any one of Claims 1-4 with the base material. Hardened | cured material of the photosensitive resin composition in any one of Claims 1-5 . A photosensitive resin composition according to any one of claims 1 to 4 is applied onto a desired support, and after drying, the photosensitive resin composition layer is exposed to a predetermined pattern, post-exposure baked, and a resin. The pattern formation method characterized by developing a composition layer and heat-processing the obtained resin pattern, and obtaining the cured resin pattern of a predetermined shape. The base material of the laminated body of Claim 5 is removed, it affixes on the said desired support body, the said photosensitive resin composition layer is exposed to a predetermined pattern, a post-exposure baking is carried out, and the resin composition is developed. Then, the obtained resin pattern is heat-treated to obtain a cured resin pattern having a predetermined shape.