JP4789733B2 - 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 that can form a pattern with high resolution and a high aspect ratio and is excellent in sensitivity, a laminate thereof, a cured product thereof, and a pattern forming method using the composition.

  Photolithographically processable resists have recently been widely used in semiconductor and MEMS micromachine 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. High aspect ratios are required for advanced electropackage applications. On the other hand, a MEMS application requires a resist capable of forming a uniform spin coating film, maintaining a straight shape in a thick film of 100 μm or more, and photolithography with a high aspect ratio. 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 thickness of the film because the dinaphthoquinone type (DNQ) photoreactant in the near-ultraviolet region wavelength (350 to 450 nm) 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.

  It is known that a negative-type chemical amplification type thick film photolithography processable composition has very low light absorption in a wavelength range of 350 to 450 nm. The composition of this resist is polyfunctional bisphenol A novolak epoxy resin (EPON SU-8 resin manufactured by Resolution Performance Products), CYRACURE UVI-6974 manufactured by Dow Chemical (this photocationic polymerization initiator is an aromatic sulfonium hexahexa A photocationic polymerization initiator such as a propylene carbonate solution of fluoroantimonate). 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 superior 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 crosslinking under a strong acid catalyst, and high transmittance is a resist performance that allows uniform light irradiation through a thick film to form a pattern with an aspect ratio of 10 or more with a thick film of 100 μm 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. For example, a useful photocationic polymerization initiator containing carbonyl-p-phenylenethioether and having an appropriate absorbance is disclosed (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 sold by Micro Chem and are used in particular in MEMS device components. For example, the “SU-8 series” provided by Micro-Chem 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, the aspect ratio is 100 μm 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 has 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 having a thickness 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. The effectiveness of the invention claimed in that document for increased strength is demonstrated by fracture toughness and flexural modulus. The tough materials according to the invention comprise various thermoplastics, hydroxyl group-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. The properties of these compositions do not provide a reference for photoimaging applications when patterning exposure is performed with UV, X-ray, or EB irradiation.

Many proposals have been made on a photoresist composition containing an 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 photocurable compositions. Many of them will be useful as photoimageable resists for permanent film applications. 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.
Accordingly, it would be desirable to provide a composition comprising an epoxy resin based on a cationically cured SU-8 resin capable of photoimaging having good image resolution, thermal stability, chemical resistance and solvent resistance. Yes. At the same time, it is desirable to improve the performance of adhesion, peeling, cracks, stress, and flexibility.

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. Has a problem that it cannot be faithfully reproduced in the resin pattern. Moreover, although the photocationic polymerization initiator containing SbF6- has a relatively high sensitivity, there is also 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 its problem is to provide a photosensitive resin composition that can form a pattern with high resolution and high aspect ratio, and is highly sensitive and less toxic. There is to do.

  In order to solve the above-mentioned problems, the present inventors have intensively studied, experimented, and studied about high sensitivity and high resolution in the photosensitive resin composition, and as a result, specific polyfunctional epoxy resins and phenolic curing agents have been obtained. And a specific photocationic polymerization initiator are combined to prepare a photosensitive resin composition. By using this photosensitive resin composition to form a resin pattern, a resin pattern with high sensitivity and high aspect ratio can be obtained. It was found that it can be formed. That is, the configuration of the present invention is as follows.

(1) A solid polyfunctional epoxy resin (A) having an epoxy equivalent of 150 to 400 g / eq and a softening point at room temperature of 25 ° C. or higher, a phenolic curing agent (B) having a hydroxyl equivalent of 90 to 300 g / eq, And a cationic photopolymerization initiator (C) that is sulfonium tris (pentafluoroethyl) trifluorophosphate, the component (A), the component (B), and the component (C) The component (A) is blended in an amount of 50 to 90% by weight, the component (B) is blended in an amount of 1 to 35% by weight, and the component (C) The photosensitive resin composition whose compounding ratio of is 1 to 15 weight%.

  (2) The photosensitive resin composition according to item (1), wherein the cationic photopolymerization initiator (C) is a compound represented by the following formula (1).

(3) The phenolic curing agent (B) has a phenol novolak resin, a cresol novolak resin, a polyfunctional bisphenol A novolak resin, a biphenylphenol novolac resin, a phenol resin having a trishydroxyphenylmethane skeleton, and a terpene diphenol skeleton. The photosensitive resin composition according to (1) or (2) above, which is at least one phenolic curing agent selected from the group consisting of phenolic resins.

(4) The polyfunctional epoxy resin (A) is a polyfunctional bisphenol A novolac epoxy resin, bisphenol A novolac epoxy resin, cresol novolac epoxy resin, biphenylphenol novolac epoxy resin, or alcohol of bisphenol F epoxy resin. The photosensitive resin composition according to any one of (1) to (3) above, which is at least one polyfunctional epoxy resin selected from the group consisting of epoxy resins obtained by a reaction product of a reactive hydroxyl group and epichlorohydrin. object.

(5) The photosensitive resin composition according to any one of (1) to (4) above, further containing a reactive epoxy monomer (D).
(6) The photosensitive resin composition further comprising a solvent (E), wherein the solid content concentration is from 5 to 95% by weight, according to any one of (1) to (5) above. Photosensitive resin composition.
(7) A photosensitive resin composition laminate in which the photosensitive resin composition according to any one of (1) to (5) above is sandwiched between substrates.
(8) A cured product of the photosensitive resin composition according to any one of (1) to (7) above.

(9) The photosensitive resin composition according to any one of (1) to (6) above is applied on a desired support, and after drying, the layer of the photosensitive resin composition has a predetermined pattern. A pattern forming method comprising: exposing to light, baking after exposure, developing the resin composition layer, and heat-treating the obtained resin pattern to obtain a cured resin pattern having a predetermined shape.
(10) The substrate of the laminate described in (7) above is removed, and the substrate is attached onto a desired support, the photosensitive resin composition layer is exposed to a predetermined pattern, post-exposure baked, and resin The pattern formation method including developing a composition and heat-treating the obtained resin pattern to obtain a cured resin pattern having a predetermined shape.

  The photosensitive resin composition of 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.

Hereinafter, embodiments of the present invention will be described.
The photosensitive resin composition of the present invention is a photocationic polymerization initiator which is a salt of a specific polyfunctional epoxy resin (A), a phenolic curing agent (B), and tris (pentafluoroethyl) trifluorophosphate ion of sulfonium. (C) is contained, and a resin pattern having high sensitivity and a high aspect ratio can be formed. Various combinations of these are possible, but in particular, photocationic polymerization initiation which is a compound represented by the above formula (1) with a polyfunctional epoxy resin and a phenolic curing agent (eg, manufactured by Meiwa Kasei Co., Ltd., H-1). A combination with an agent is most preferred.

  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 polyfunctional epoxy resin (A) used in the present invention can be obtained from the market. For example, bisphenol A type epoxy resin, octafunctional bisphenol A novolak type epoxy resin (eg, EPON SU-8 manufactured by Resolution Performance Products), obtained by reaction of alcoholic hydroxyl group of bisphenol F type epoxy resin with epichlorohydrin Epoxy resin (eg, NER-7604 manufactured by Nippon Kayaku Co., Ltd.), epoxy resin obtained by reaction of alcoholic hydroxyl group of bisphenol A type epoxy resin and epichlorohydrin (eg, NER-1302 manufactured by Nippon Kayaku Co., Ltd.) , O-cresol novolak type epoxy resin (for example, EOCN4400 manufactured by Nippon Kayaku Co., Ltd.), obtained by reacting a phenolic hydroxyl group of a resin obtained by reacting di (methoxymethylphenyl) with phenol and epichlorohydrin. Bi Phenylphenol novolac type epoxy resin (for example, Nippon Kayaku Co., Ltd. NC-3000H) etc. are mentioned. The epoxy equivalent of these polyfunctional epoxy resins (A) is preferably 150 to 400, and if it is smaller than this range, it is not preferred in that the cured product is likely to warp or crack. On the other hand, when it is larger than this range, the strength and durability of the cured film are poor, which is not preferable. In the case of a photosensitive resin composition using a polyfunctional epoxy resin (A) having a low softening point, mask sticking is likely to occur during patterning, and also softens at room temperature when used as a dry film resist. Therefore, it is not preferable. On the other hand, in the case of a photosensitive resin composition using a polyfunctional epoxy resin (A) having a high softening point, it is difficult to soften when laminating a dry film resist to a substrate, and the bonding property to the substrate becomes worse. It is not preferable. For the above reasons, the preferred softening point of the polyfunctional epoxy resin (A) is 40 to 100 ° C, more preferably 50 to 90 ° C. These polyfunctional epoxy resins (A) can be used alone or in combination of two or more. When the photosensitive resin composition is coated on a substrate or used as a dry film resist, it is important to maintain a sufficient hardness as a solid material so that the dry film surface is not sticky. Therefore, the blending ratio of the polyfunctional epoxy resin (A) component is 50 weights with respect to the total of the polyfunctional epoxy resin (A) component, the phenolic curing agent (B) component, and the photocationic polymerization initiator (C) component. % To 90% by weight, particularly preferably 60% to 70% by weight. If it is lower than this range, it is not preferable in that the dry film tends to be sticky.

  Examples of the phenolic curing agent (B) used in the present invention include a phenol novolak resin, a cresol novolak resin, a polyfunctional bisphenol A novolak resin, a biphenylphenol novolak resin, a phenol resin having a trishydroxyphenylmethane skeleton, and a terpene diphenol. Examples thereof include phenol resins having a skeleton and phenol resins made from various phenols such as bisphenol A and bisphenol F. When the hydroxyl group equivalent of these phenol type curing agents (B) is small, unreacted hydroxyl groups remain, which is not preferable in that the durability of the cured product may be adversely affected. On the other hand, when the hydroxyl equivalent is large, the cross-linking ratio with the epoxy is small, the characteristics of the phenolic curing agent (B) are hardly expressed, and this is not preferable in that the contribution to the durability of the cured film is reduced. For the above reasons, the preferred hydroxyl equivalent of the phenol-based curing agent (B) is 90 to 300, more preferably 100 to 250. These phenolic curing agents (B) may be used alone or in combination of two or more. In addition, amine-based curing agents and acid anhydride-based curing agents that are generally used as curing agents for epoxy compositions have poor liquid storage stability over time when added to a resist such as the present invention, Storage at room temperature is difficult and impractical. Since the phenol-based curing agent (B) component is added for the purpose of more effectively extracting the physical properties of the epoxy resin, it is not necessary to add a large amount. The blending ratio is preferably 1% by weight to 35% by weight, particularly preferably based on the total of the polyfunctional epoxy resin (A) component, the phenolic curing agent (B) component, and the cationic photopolymerization initiator (C) component. Is 5 to 25% by weight.

  The photocationic polymerization initiator (C) is sulfonium tris (pentafluoroethyl) trifluorophosphate.

  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 cationic photopolymerization initiator, triphenylsulfonium and 4- (phenylthio) phenyldiphenylsulfonium are more preferable, and 4- (phenylthio) phenyldiphenylsulfonium represented by the following formula (2) is most preferable.

  Since the cationic photopolymerization initiator (C) component has an action of absorbing light, when a large amount of the component (C) is used in a thick film (specifically, 50 μm or more) (specifically, 15% by weight) If the amount exceeds this, the light at the time of curing cannot be sufficiently transmitted to the deep part. On the other hand, when a small amount is used (specifically, less than 3% by weight), it is difficult to obtain a sufficient curing rate. In the case of a thin film, sufficient performance is exhibited by addition of a small amount (specifically, 1% by weight or more). On the contrary, when the component (C) is used in a large amount, there is no problem with respect to the light transmission to the deep part, but it is not economical because an expensive initiator is unnecessarily used. From these points, the blending ratio of the component (C) is 1% by weight to 15% by weight with respect to the solid content of the total of the component (A), the component (B), and the component (C) as the solid content of the resist. Is preferable, and 3 to 10% by weight is particularly preferable.

  As the reactive epoxy monomer (D) component used in the present invention, a glycidyl ether compound can be used. For example, diethylene glycol diglycidyl ether, hexanediol diglycidyl ether, dimethylolpropane diglycidyl ether, polypropylene glycol diglycidyl ether (Asahi Denka Kogyo Co., Ltd., ED506), trimethylolpropane triglycidyl ether (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 (D) component is used for the purpose of improving the reactivity of the resist and the physical properties of the cured film, but many of the reactive epoxy monomer components are liquid. Accordingly, when the component is in a liquid form, if it is added in an amount of more than 20% by weight, it is inappropriate because the film after solvent removal is likely 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.

  In the present invention, the composition of the polyfunctional epoxy resin (A), phenolic curing agent (B), photocationic polymerization initiator (C) and reactive epoxy monomer (D) is diluted with the solvent (E) for use. Provided. Examples of such a solvent (E) include ketones such as methyl ethyl ketone and cyclohexanone, aromatic hydrocarbons such as toluene, xylene and tetramethylbenzene, glycol ethers such as dipropylene glycol dimethyl ether and dipropylene glycol diethyl ether, Organic solvents such as esters such as ethyl acetate, butyl acetate, butyl cellosolve acetate and carbitol acetate, aliphatic hydrocarbons such as octane and decane, petroleum solvents such as petroleum ether, petroleum naphtha, hydrogenated petroleum naphtha and solvent naphtha Etc. These solvent (E) can be used individually or in mixture of 2 or more types. The solvent (E) component is added for the purpose of adjusting the film thickness and applicability when applied to the substrate, and the solubility of the main component, the volatility of the (E) component, and the liquid viscosity of the composition are appropriate. Therefore, it is preferably 5 to 95% by weight, particularly preferably 10 to 90% by weight based on the entire resist.

  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 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 substrate, it can be used within a range that does not adversely affect the effect even in a small amount. The proportion of use is preferably 15% by weight or less, particularly preferably 10% by weight or less, based on the photosensitive resin composition.

In the present invention, a sensitizer may be used to absorb ultraviolet rays and to supply the absorbed light energy to the photocationic polymerization initiator. As the sensitizer, for example, an anthracene compound having an alkoxy group at the 9th and 10th positions (9,10-dialkoxy-anthracene derivative) is preferable. Examples of the alkoxy group include a methoxy group, an ethoxy group, an alkoxy group of C ₁ -C _4, such as a propoxy group. The 9,10-dialkoxy-anthracene derivative may further have a substituent. Examples of the substituent include a fluorine atom, a chlorine atom, a bromine atom, a halogen atom such as iodine atom, a methyl group, an ethyl group, a propyl group or a sulfonic acid alkyl ester group having C ₁ -C ₄ such groups, alkyl carboxylic acid An ester group etc. are mentioned. Examples of the alkyl in the sulfonic acid alkyl ester group and the carboxylic acid alkyl ester include C _{1 to} C ₄ alkyl such as methyl, ethyl, and propyl. The substitution position of these substituents is preferably the 2-position.

  Examples of the 9,10-dialkoxy-anthracene derivative include 9,10-dimethoxy-anthracene, 9,10-diethoxy-anthracene, 9,10-dipropoxy-anthracene, 9,10-dimethoxy-2-ethyl-anthracene, 9 , 10-diethoxy-2-ethyl-anthracene, 9,10-dipropoxy-2-ethyl-anthracene, 9,10-dimethoxy-2-chloro-anthracene, 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 (C) component.

  In the present invention, when it is necessary to reduce the adverse effect of ions derived from the photocationic polymerization initiator (C), 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 can 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, naphthalene black and the like. Examples of the thickener include olben, benton, montmorillonite and the like. Examples of the antifoaming agent include silicone-based, fluorine-based and polymer-based antifoaming agents. When using these additives, etc., the amount used is, for example, about 0.1 to 30% by weight in the photosensitive resin composition of the present invention, but it may be appropriately increased or decreased depending on the purpose of use. obtain.

  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. it can. 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. You may add the said adhesiveness imparting agent, a sensitizer, an ion catcher, a thermoplastic resin, a coloring agent, a thickener, an antifoamer, a leveling agent, and an inorganic filler as needed. 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. About a heat treatment is performed to remove the solvent to form a photosensitive resin composition layer. Then, after placing a mask having a predetermined pattern and irradiating with ultraviolet rays, and performing heat treatment at 50 to 130 ° C. for about 1 to 50 minutes, the unexposed part is developed at room temperature to 50 ° C. using a developer. Development is performed for about 1 to 180 minutes to form a pattern, and then heat treatment is performed at 130 to 200 ° C. to obtain a permanent protective film satisfying various characteristics. 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, etc. Similarly to the above, 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.

(Preparation of photosensitive resin composition)
Examples 1 to 3 (Comparative Example 1)
In accordance with the blending amount shown in Table 2 (unit is part by weight), the polyfunctional epoxy resin, the photocationic polymerization initiator, and other components are stirred and mixed in a flask with a stirrer at 60 ° C. for 1 hour to obtain a photosensitive resin composition. Got.

(Patterning of photosensitive resin composition)
Examples 1 to 3 (Comparative Example 1)
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 20 minutes. Thereafter, pattern exposure (soft contact, i-line) was performed using an i-line exposure apparatus (mask aligner: manufactured by USHIO INC.). Next, after exposure baking (PEB) at 95 ° C. for 6 minutes with a hot plate, development processing was performed at 23 ° C. for 7 minutes by immersion using propylene glycol monomethyl ether acetate to form a cured resin pattern on the substrate. Obtained.

(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.

(Optimal exposure)
Exposure amount (aspect ratio) with the best mask transfer accuracy
Film thickness / The finest pattern width closely adhered in the formed resist pattern

note:
(A-1): Multifunctional epoxy resin biphenylphenol type polyfunctional epoxy resin, product name: NC3000H manufactured by Nippon Kayaku Co., Ltd. (A-2): Multifunctional epoxy resin modified bisphenol F type epoxy resin, product name: NER7694 Nippon Kayaku Co., Ltd. (A-3): Multifunctional Epoxy Resin Bisphenol A Novolak Type Polyfunctional Epoxy Resin, Product Name: EPON SU-8 Resolution Performance Products (B): Phenol Curing Agent Phenol Novolac resin, product name: H-1 Meiwa Kasei Co., Ltd. (C-1): Photocationic polymerization initiator product name CPI-210S San Apro Co., Ltd. (C-2): Photocationic polymerization initiator product name UVI -6974 50% propylene carbonate solution (D) manufactured by Dow Chemical Co., Ltd .: Reactive epoxy monomer Product name: ED506 Denka Kogyo Co., Ltd. (E): Solvent Cyclopentanone (F): Leveling agent trade name MegaFuck F-470 Dainippon Ink & Chemicals, Inc. (G): Silane coupling agent trade name S-510 Chisso Made by

  As shown in Table 2, Examples 1 to 3 were all good results.

Example 4
(Preparation of photosensitive resin composition)
10 parts by weight of multifunctional epoxy resin (trade name NC3000H manufactured by Nippon Kayaku Co., Ltd.), 10 parts by weight of multifunctional epoxy resin (trade name NER7604 manufactured by Nippon Kayaku Co., Ltd.), multifunctional epoxy resin (trade name EPON) 80 parts by weight of SU-8 Resolution Performance Products), 4.6 parts by weight of a cationic photopolymerization initiator (trade name CPI-210S manufactured by San Apro Co., Ltd.), a reactive epoxy monomer (trade name ED506 Asahi) A photosensitive resin composition obtained by mixing 4 parts by weight of Denka Kogyo Co., Ltd. and 30 parts by weight of methyl ethyl ketone was obtained.

(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 heated at 65 ° C. for 10 minutes and at 80 ° C. for 15 minutes by a hot air convection dryer. After drying, a 60 μm-thick PP film (cover film, manufactured by Toray Industries, Inc.) was laminated on the photosensitive composition layer to form a 40 μm-thick photosensitive resin composition laminate.

The cover film of the photosensitive resin composition laminate is peeled off, 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, and the base film is peeled off. This operation was further repeated to obtain a photosensitive resin composition laminate having a thickness of 80 μm. 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 Electric Co., Ltd.). Then, PEB was performed for 6 minutes at 95 ° C. using a hot plate, and development processing was performed for 7 minutes at 23 ° C. by immersion using PGMEA to obtain a cured resin pattern on the substrate. Good results were obtained with an optimum exposure of 200 mJ / cm ² and an aspect ratio of 9.0.

  As is clear from the comparison between the results of Examples 1 to 4 and the comparative example, the combination of a polyfunctional epoxy resin having a specific structure, a phenolic curing agent, and a specific photocationic polymerization initiator cannot be obtained in other combinations. It was found that a resin pattern having a high sensitivity and a high aspect profile can be obtained.

  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 (9)

  Solid polyfunctional epoxy resin (A) having an epoxy equivalent of 150 to 400 g / eq and a softening point of 25 ° C. or higher at room temperature, phenolic curing agent (B) having a hydroxyl equivalent of 90 to 300 g / eq, and sulfonium tris A photosensitive resin composition comprising a photocationic polymerization initiator (C) that is (pentafluoroethyl) trifluorophosphate, comprising the component (A), the component (B), and the component (C). The blending ratio of the component (A) is 50 to 90% by weight with respect to the total, the blending ratio of the component (B) is 1 to 35% by weight, and the blending ratio of the component (C) is 1. The photosensitive resin composition which is -15 weight%. A compound in which the cationic photopolymerization initiator (C) is represented by the following formula (1)

The photosensitive resin composition of Claim 1 which is.   The phenolic curing agent (B) is a phenol novolak resin, a cresol novolak resin, a polyfunctional bisphenol A novolak resin, a biphenylphenol novolak resin, a phenol resin having a trishydroxyphenylmethane skeleton, and a phenol resin having a terpene diphenol skeleton. The photosensitive resin composition of Claim 1 or 2 which is at least 1 type of phenol-type hardening | curing agent chosen from the group which consists of.   The polyfunctional epoxy resin (A) is a polyfunctional bisphenol A novolac epoxy resin, a bisphenol A novolac epoxy resin, a cresol novolac epoxy resin, a biphenylphenol novolac epoxy resin, and an alcoholic hydroxyl group of a bisphenol F epoxy resin. The photosensitive resin composition of any one of Claims 1-3 which is at least 1 type of polyfunctional epoxy resin chosen from the group which consists of an epoxy resin obtained by the reaction material with epichlorohydrin. Furthermore, it is the photosensitive resin composition formed by containing a solvent (E), Comprising: Solid content concentration is 5 to 95 weight%, The photosensitive resin composition of any one of Claims 1-4 . The photosensitive resin composition laminated body which pinched | interposed the photosensitive resin composition of any one of Claims 1-4 with the base material. Hardened | cured material of the photosensitive resin composition of any one of Claims 1-5 . The photosensitive resin composition according to any one of claims 1 to 5 is applied on a desired support, and after drying, the layer of the photosensitive resin composition is exposed to a predetermined pattern, followed by baking after exposure. And developing the resin composition layer, and heat-treating the obtained resin pattern to obtain a cured resin pattern having a predetermined shape. The base material of the laminated body of Claim 6 is removed, it affixes on a desired support body, the layer of the said photosensitive resin composition is exposed to a predetermined pattern, a post-exposure baking is carried out, and the resin composition is developed. The pattern formation method including heat-processing the obtained resin pattern and obtaining the cured resin pattern of a predetermined shape.