Photosensitive resin composition and cured product thereof

Abstract

To provide a photosensitive resin composition which is excellent in resolution and adhesion to a substrate and reduces dew condensation that occurs inside a package when the temperature rapidly changes.SOLUTION: The photosensitive resin composition contains a cationically curable resin (A), a photocationic polymerization initiator (B), and a quencher (C). The cationically curable resin (A) contains 60 mass% or more of a polyfunctional epoxy resin (a-1) having a softening point of 50°C or higher and / or an acid-modified product (a-2) of a polyfunctional epoxy resin having a softening point of 50°C or higher. The quencher (C) contains a compound represented by the following formula (1) (where R1-R3 each independently represent an alkyl group or a phenyl group).SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a photosensitive resin composition with excellent resolution that is useful in the manufacture of MEMS (micro-electromechanical systems) components, micromachine components, microfluidic components, μ-TAS (micro-total analytical systems) components, inkjet printer components, microreactor components, conductive layers, LIGA components, molds and stamps for micro-injection molding and thermal embossing, screens or stencils for micro-printing applications, MEMS package components, semiconductor package components, BioMEMS and biophotonic devices, and printed circuit boards. The present invention further relates to a cured product of the photosensitive resin composition that exhibits excellent adhesion to substrates and reduces condensation generated inside the package during rapid temperature changes. [Background technology]

[0002] Photolithographic resists are now widely used in semiconductor, MEMS, and micromachine applications. In these applications, photolithography is achieved by patterning and exposing a substrate, followed by development with a developer to selectively remove either the exposed or unexposed areas. Photolithographic resists (photoresists) come in positive and negative types; the positive type dissolves in the developer, while the negative type remains insoluble. Advanced electropackaging and MEMS applications require not only the ability to form uniform spin-coated films, but also high aspect ratios, straight sidewall shapes in thick films, and high adhesion to the substrate. Here, the aspect ratio is calculated from the resist film thickness / pattern line width and is an important characteristic indicating the performance of photolithography.

[0003] Known photoresists include a negative-type chemically amplified photoresist composition containing a polyfunctional bisphenol A novolac epoxy resin (trade name EPON SU-8 resin, manufactured by Resolution Performance Products) and a photocationic polymerization initiator such as Dow Chemical's CYRACURE UVI-6974 (this photocationic polymerization initiator consists of a propylene carbonate solution of aromatic sulfonium hexafluoroantimonate). This photoresist composition is known as a photoresist composition that can be processed by thick-film photolithography because it has very low light absorption in the wavelength range of 350 to 450 nm. This photoresist composition can be applied to various substrates by methods such as spin coating or curtain coating, and then the solvent can be evaporated by baking to form a solid photoresist layer with a thickness of 100 μm or more. Furthermore, photolithography can be performed by irradiating this solid photoresist layer with near-ultraviolet light through a photomask using various exposure methods such as contact exposure, proximity exposure, or projection exposure. Next, by immersing the substrate in a developing solution and dissolving the unexposed areas, a high-resolution negative image of the photomask can be formed on the substrate.

[0004] On the other hand, in the fields of MEMS components and MEMS and semiconductor packages, it is known that the physical properties of the package material affect the reliability of the device. MEMS elements and semiconductor elements are susceptible to degradation of their properties due to changes in ambient temperature and humidity, or the influence of fine dust and debris, and are also prone to damage from mechanical vibrations and shocks. To protect them from these external factors, MEMS elements and semiconductor elements are used in the form of packages, either sealed with various materials or enclosed in a hollow structure (cavity) surrounded by an outer wall of various materials. In the case of hermetic sealing methods using metals or ceramics for the sealing agent or outer wall material, the resulting package is highly reliable, but has drawbacks such as high manufacturing costs and poor dimensional accuracy. In contrast, in the case of resin sealing using resin for the sealing agent or outer wall material, conventional resins have relatively low manufacturing costs and high dimensional accuracy, but have problems with moisture resistance and heat resistance. For example, problems include the delamination of the sealing agent from the substrate or element due to moisture absorbed by the resin material from the external environment, and defects caused by outgassing from the package when exposed to high-temperature environments. Furthermore, in recent years, in packages having cavities made of resin material, when cooled rapidly after high-temperature heating processes such as solder reflow, moisture contained within the resin or generated by the resin curing reaction condenses inside the cavity, causing a degradation in the characteristics of MEMS and semiconductor devices.

[0005] Patent Document 1 describes how the storage stability of a composition comprising a compound selected from oxetane compounds and epoxy compounds, and an onium salt which is a cationic polymerization initiator, can be improved by incorporating a phosphine oxide derivative of a specific structure. However, this document makes no mention of the composition's resolution, adhesion to the substrate, or effect on reducing condensation during rapid temperature changes. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Patent No. 3817620 [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] The present invention has been made in view of the above circumstances, and aims to provide a photosensitive resin composition that exhibits excellent resolution and adhesion to a substrate, and reduces condensation generated inside the package during rapid temperature changes. [Means for solving the problem]

[0008] As a result of diligent research, the inventors of the present invention have found that a photosensitive resin composition containing a specific cationic curable resin, a photocationic polymerization initiator, and a quencher of a specific structure can solve the above problems, and have completed the present invention.

[0009] The present invention relates to the following embodiments. [1] A photosensitive resin composition comprising a cationic curable resin (A), a photocationic polymerization initiator (B), and a quencher (C), wherein the cationic curable resin (A) contains 60% by mass or more of a polyfunctional epoxy resin (a-1) with a softening point of 50°C or higher and / or an acid-modified product of a polyfunctional epoxy resin (a-2) with a softening point of 50°C or higher, and the quencher (C) is of the following formula (1)

[0010] [ka]

[0011] (In the formula, R 1 ~R 3 A photosensitive resin composition containing a compound represented by (where each independently represents an alkyl group or a phenyl group). [2]R 1 ~R 3 The photosensitive resin composition according to the preceding paragraph [1], wherein is a phenyl group. [3] A dry film resist comprising the photosensitive resin composition described in item [1] or [2] above. [4] A cured product of the photosensitive resin composition described in item [1] or [2] above. [Effects of the Invention]

[0012] The photosensitive resin composition of the present invention exhibits excellent resolution and adhesion to substrates, and also reduces condensation that occurs inside the package during rapid temperature changes, making it suitable for use in MEMS components, micromachine components, semiconductor package components, and the like. [Modes for carrying out the invention]

[0013] The present invention will be described below. The photosensitive resin composition of the present invention is a photosensitive resin composition comprising a cationic curable resin (A), a photocationic polymerization initiator (B), and a quencher (C), wherein the cationic curable resin (A) contains 60% by mass or more of a polyfunctional epoxy resin (a-1) with a softening point of 50°C or higher and / or an acid-modified product of a polyfunctional epoxy resin (a-2) with a softening point of 50°C or higher, and the quencher (C) contains a compound represented by the above formula (1).

[0014] The cationic curable resin (A) used in the photosensitive resin composition of the present invention (hereinafter simply referred to as "component (A)") contains 60% by mass or more of a polyfunctional epoxy resin (a-1) (hereinafter simply referred to as "component (a-1)") with a softening point of 50°C or higher and / or an acid-modified product of a polyfunctional epoxy resin (a-2) (hereinafter simply referred to as "component (a-2)"). By containing 60% by mass or more of component (a-1) and / or component (a-2) with a softening point of 50°C or higher in the cationic curable resin (A), it is possible to prevent condensation from occurring inside the package during reflow testing and to prevent the film obtained using the photosensitive resin composition from becoming sticky. The content of component (a-1) and / or component (a-2) in component (A) is more preferably 70% by mass or more.

[0015] (a-1) component is not particularly limited as long as it is a compound having a softening point of 50 °C or higher and two or more epoxy groups in one molecule. Examples include novolacs obtained by reacting phenols (phenol, alkyl-substituted phenol, naphthol, alkyl-substituted naphthol, dihydroxybenzene, dihydroxynaphthalene, etc.) with formaldehyde under an acidic catalyst, and novolak-type epoxy resins having a softening point of 50 °C or higher obtained by reacting with halohydrins such as epichlorohydrin and methyl epichlorohydrin. Specific examples of the (a-1) component include KM-N-LCL, EOCN-102S, EOCN-103S, EOCN-104S, EOCN-1020, EOCN-4400H, EPPN-201, EPPN-501, EPPN-502, XD-1000, BREN-S, NC-3000H, NC-7000L, NC-6000H, GTR-1800 (all are trade names, manufactured by Nippon Kayaku Co., Ltd.) and the like.

[0016] The softening point of the (a-1) component is preferably 50 to 120 °C, more preferably 60 to 110 °C. The softening point herein is the value measured by a method based on the ring and ball method of JIS K7234. The epoxy equivalent of the (a-1) component is preferably 100 to 500 g / eq., more preferably 200 to 350 g / eq. The epoxy equivalent herein is the value measured by a method based on JIS K7236.

[0017] (a-2) component is a compound obtained by reacting a polybasic acid anhydride (z) (hereinafter simply referred to as "(z) component") with the alcoholic hydroxyl group of a reaction product (xy) of an epoxy compound (x) having two or more epoxy groups (hereinafter simply referred to as "(x) component") and a monocarboxylic acid compound (y) having an alcoholic hydroxyl group (hereinafter simply referred to as "(y) component").

[0018] The raw material for component (a-2), component (x), is not particularly limited as long as it is a compound having two or more epoxy groups, but examples include bifunctional epoxy resins having epoxy groups at both ends, such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, and bisphenol S type epoxy resin. The epoxy equivalent of these (x) components is usually 300 to 1,300 g / eq., preferably 500 to 1,200 g / eq., and more preferably 700 to 1,100 g / eq. The softening point of component (x) is preferably 50°C to 120°C, more preferably 60°C to 110°C. Specific examples of (x) components having the above epoxy equivalent include bisphenol A type epoxy resins such as jER1003 and jER1004 (manufactured by Mitsubishi Chemical Corporation), and bisphenol F type epoxy resins such as jER4004P and jER4005P (manufactured by Mitsubishi Chemical Corporation).

[0019] Examples of component (y), which is a raw material for component (a-2), include monomethylolpropionic acid, dimethylolpropionic acid, monomethylolbutanoic acid, and dimethylolbutanoic acid. Dimethylolpropionic acid and dimethylolbutanoic acid are preferred because they allow for the introduction of a large amount of alcoholic hydroxyl groups that can react with component (z) into the reaction product of component (x) and component (y). These components (y) may be used individually or as a mixture of two or more.

[0020] The reaction between component (x) and component (y) is usually carried out in a solvent that does not contain hydroxyl groups. Examples of such solvents include ketones such as acetone, ethyl methyl ketone, and cyclohexanone; aromatic hydrocarbons such as benzene, toluene, xylene, and tetramethylbenzene; glycol ethers such as ethylene glycol dimethyl ether, ethylene glycol diethyl ether, dipropylene glycol dimethyl ether, and dipropylene glycol diethyl ether; esters such as ethyl acetate, butyl acetate, butyl cellosolve acetate, carbitol acetate, propylene glycol monomethyl ether acetate, and γ-butyrolactone; alcohols such as methanol, ethanol, ceresolve, and methyl ceresolve; aliphatic hydrocarbons such as octane and decane; and petroleum solvents such as petroleum ether, petroleum naphtha, hydrogenated petroleum naphtha, and solvent naphtha.

[0021] For the reaction between component (x) and component (y), it is preferable to use a catalyst to promote the addition reaction. Specific examples of catalysts include triethylamine, benzyldimethylamine, triethylammonium chloride, benzyltrimethylammonium bromide, benzyltrimethylammonium iodide, triphenylphosphine, triphenylstyvin, chromium octanoate, and zirconium octanoate. The amount of catalyst used is usually 0.1 to 10% by mass relative to the total of components (x) and (y). The reaction temperature is usually 60 to 150°C, and the reaction time is usually 5 to 60 hours.

[0022] The addition ratio of the carboxyl group of component (y) to the epoxy group of component (x) is preferably 80% or more, more preferably 90 equivalents or more, and even more preferably 100%. By setting the addition ratio of component (y) to the epoxy group of component (x) to 80% or more, a large amount of alcoholic hydroxyl groups derived from component (y) are introduced into the reaction product of component (x) and component (y), and as a result the amount of component (z) added to the reaction product of component (x) and component (y) increases, the developability of the photosensitive resin composition is improved.

[0023] Examples of component (z), which is a raw material for component (a-2), include succinic anhydride, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, maleic anhydride, trimellitic anhydride, and pyromellitic anhydride. Succinic anhydride, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, or maleic anhydride are preferred, and tetrahydrophthalic anhydride is more preferred. These components (z) may be used individually or in combination of two or more. The addition reaction between the reactants of component (x) and component (y) and component (z) can be carried out simply by adding the required amount of component (z) to the solution containing the reactants of component (x) and component (y) obtained above and heating it. The reaction temperature is usually 60 to 150°C, and the reaction time is usually 5 to 10 hours.

[0024] The addition ratio of the acid anhydride of component (z) to the alcoholic hydroxyl groups of the reaction product of component (x) and component (y) is preferably 80% or more, more preferably 90% or more, and even more preferably 100%. By setting the addition ratio of component (z) to the alcoholic hydroxyl groups of the reaction product of component (x) and component (y) to 80% or more, a large amount of carboxyl groups are introduced by the addition reaction of component (z), improving the alkali developability of the photosensitive resin composition. The solid acid value of component (a-2) obtained by the above method is preferably 90 to 105 mg·KOH / g. The solid acid value used herein is the value measured according to the method compliant with JIS K0070. (a-2) The softening point of component is preferably 50 to 120°C, and more preferably 60 to 110°C. (a-2) The weight-average molecular weight of component is preferably 500 to 15,000, and more preferably 500 to 9,000.

[0025] Component (A) may contain less than 40% by mass of a cationic polymerizable resin (a-3) other than components (a-1) and (a-2) (hereinafter simply referred to as "component (a-3)"). Component (a-3) is not particularly limited as long as it is a compound (resin) other than components (a-1) and (a-2) and has a cationic curable functional group, but examples include glycidyl ether epoxy compounds that are liquid at room temperature (e.g., bisphenol A type glycidyl ether, bisphenol F type glycidyl ether, etc.); alicyclic glycidyl ether epoxy compounds (e.g., hydrogenated bisphenol A type glycidyl ether, hydrogenated bisphenol F type glycidyl ether, etc.); aliphatic glycidyl ether type epoxy compounds; alicyclic epoxy compounds; epoxy-modified siloxane compounds, etc. Component (a-3) may be used alone or in combination of two or more. (a-3) Specific examples of components include, for example, JER-828, JER-806, YX-8000 (manufactured by Mitsubishi Chemical Corporation), Celoxide 2021P (manufactured by Daicel Corporation), Denacol EX-321, Denacol EX-145 (manufactured by Nagase ChemteX Corporation), and TEPIC-VL (manufactured by Nissan Chemical Corporation).

[0026] The (B) photocationic polymerization initiator used in the photosensitive resin composition of the present invention (hereinafter simply referred to as "component (B)") is a compound that generates cations upon irradiation with radiation such as ultraviolet light, far ultraviolet light, excimer lasers such as KrF and ArF, X-rays and electron beams, and these cations can initiate the polymerization reaction of a cationic curable resin (compound) such as epoxy resin. Component (B) is not particularly limited as long as it is a conventionally known photocationic polymerization initiator, but typical examples include aromatic iodonium complex salts and aromatic sulfonium complex salts.

[0027] Specific examples of aromatic iodonium complex salts include diphenyliodonium tetrakis(pentafluorophenyl) borate, diphenyliodonium hexafluorophosphate, diphenyliodonium hexafluoroantimonate, di(4-nonylphenyl)iodonium hexafluorophosphate, tolylcmyliodonium tetrakis(pentafluorophenyl) borate (manufactured by Rhodia, trade name Rhodorsil PI2074), and di(4-tert-butyl)iodonium tris(trifluoromethanesulfonyl) methanide (manufactured by BASF, trade name CGI BBI-C1).

[0028] Specific examples of aromatic sulfonium complex salts include 4-thiophenyldiphenylsulfonium hexafluoroantimonate (manufactured by Sunapro, trade name CPI-101A), thiophenyldiphenylsulfonium tris(pentafluoroethyl)trifluorophosphate (manufactured by Sunapro, trade name CPI-210S), 4-{4-(2-chlorobenzoyl)phenylthio}phenylbis(4-fluorophenyl)sulfonium hexafluoroantimonate (manufactured by ADEKA, trade name SP-172), a mixture of aromatic sulfonium hexafluoroantimonates containing 4-thiophenyldiphenylsulfonium hexafluoroantimonate (manufactured by ACETO Corporate USA, trade name CPI-6976), triphenylsulfonium tris(trifluoromethanesulfonyl)methanide (manufactured by BASF, trade name CGI TPS-C1), and tris[4-(4-acetylphenyl)sulfonylphenyl]sulfonium tris(trifluoromethylsulfonyl)methide (manufactured by BASF, trade name GSID). Examples include 26-1), tris[4-(4-acetylphenyl)sulfonylphenyl]sulfonium tetrakis(2,3,4,5,6-pentafluorophenyl) borate (manufactured by BASF, trade name Irgacure PAG290), etc.

[0029] Among these (B) components, in the photosensitive image forming process of the present invention, an aromatic sulfonium complex salt having high perpendicular rectangular processability and high thermal stability is preferred, and 4-{4-(2-chlorobenzoyl)phenylthio}phenylbis(4-fluorophenyl)sulfonium hexafluoroantimonate, a mixture of aromatic sulfonium hexafluoroantimonate containing 4-thiophenyldiphenylsulfonium hexafluoroantimonate, or tris[4-(4-acetylphenyl)sulfonylphenyl]sulfonium tetrakis(2,3,4,5,6-pentafluorophenyl)borate is more preferred. The (B) component may be used alone or in combination of two or more in the photosensitive resin composition of the present invention.

[0030] The content of the (B) component in the photosensitive resin composition of the present invention is usually 0.1 to 10% by mass, preferably 0.5 to 5% by mass, based on the (A) component. In another aspect, the mixing ratio of the (B) component in the photosensitive resin composition of the present invention may be 0.1 to 5% by mass or 0.5 to 10% by mass based on the (A) component. However, when the molar absorption coefficient of the (B) component at a wavelength of 300 to 380 nm is high, it is necessary to adjust the blending amount to an appropriate amount according to the film thickness when using the photosensitive resin composition.

[0031] The photosensitive resin composition of the present invention contains a quencher (C) represented by the above formula (1) (hereinafter simply referred to as the "(C) component"). In formula (1), R 1 to R 3 each independently represents an alkyl group or a phenyl group respectively.

[0032] The photosensitive resin composition of the present invention contains a quencher (C) represented by the above formula (1) (hereinafter simply referred to as the "(C) component"). The alkyl group represented by R 1 to R 3 in formula (1) may be either linear or branched, and the number of carbon atoms thereof is not particularly limited, but a linear or branched alkyl group having 1 to 10 carbon atoms is preferred. R in formula (1) 1~R 3 The alkyl group and phenyl group represented by may have substituents. Here, "substituted alkyl group" refers to an alkyl group in which a hydrogen atom is replaced by a substituent, and the number of substituents in the alkyl group is not particularly limited. The substituents on the alkyl group are not particularly limited, but examples include hydroxyl groups, halogen atoms, and aryl groups. R in equation (1) 1 ~R 3 Preferably, each of these is independently a linear or branched alkyl group having 1 to 10 carbon atoms, or a phenyl group, R 1 ~R 3 More preferably, the same linear or branched alkyl group having 1 to 10 carbon atoms, or a phenyl group.

[0033] (C)Specific examples of components include tributylphosphine oxide (TBPO), triphenylphosphine oxide (TPPO), tri(3-hydroxypropyl)phosphine oxide, and n-butyl-bis(3-hydroxypropyl)phosphine oxide.

[0034] The content of component (C) in the photosensitive resin composition of the present invention is typically 0.1 to 50% by mass, preferably 1 to 30% by mass, relative to the content of component (B). By setting the content of component (C) within the above range, the photosensitive resin composition of the present invention exhibits a condensation reduction effect and excellent curability. While it is permissible to use known quenchers other than the compound represented by formula (1) in component (C) as long as it does not impair the effects of the invention, it is preferable to use only the compound represented by formula (1) in component (C) because using a quencher other than the compound represented by formula (1) may result in excessive inhibition of the reaction due to an over-enhancement of the acid binding capacity, leading to a significant decrease in sensitivity, or conversely, excessively low binding capacity, resulting in a decrease in the condensation prevention effect.

[0035] The photosensitive resin composition of the present invention may contain a solvent to reduce the viscosity of the composition and improve its coatability on various substrates. The solvent is not particularly limited and can be any organic solvent commonly used in inks, paints, etc., that is capable of dissolving each component of the photosensitive resin composition. Specific examples of solvents include ketones such as acetone, ethyl methyl ketone, cyclohexanone, and cyclopentanone; aromatic hydrocarbons such as toluene, xylene, and tetramethylbenzene; glycol ethers such as ethylene glycol dimethyl ether, dipropylene glycol dimethyl ether, and dipropylene glycol diethyl ether; esters such as ethyl acetate, butyl acetate, butyl cellosolve acetate, carbitol acetate, propylene glycol monomethyl ether acetate, and γ-butyrolactone; alcohols such as methanol, ethanol, cellosolve, and methyl cellosolve; aliphatic hydrocarbons such as octane and decane; and petroleum-based solvents such as petroleum ether, petroleum naphtha, hydrogenated petroleum naphtha, and solvent naphtha. The solvent content in the photosensitive resin composition of the present invention is preferably 95% by mass or less, and more preferably 10 to 90% by mass.

[0036] The photosensitive resin composition of the present invention may contain a miscible adhesion-improving agent for the purpose of improving the adhesion of the composition to the substrate. As the adhesion-improving agent, coupling agents such as silane coupling agents or titanium coupling agents can be used. Silane coupling agents are preferred.

[0037] Examples of silane coupling agents include 3-chloropropyltrimethoxysilane, vinyltrichlorosilane, vinyltriethoxysilane, vinyltrimethoxysilane, vinyltris(2-methoxyethoxy)silane, 3-methacryloxypropyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, and 3-ureidopropyltriethoxysilane. These adhesion-imparting agents can be used individually or in combination of two or more.

[0038] Excessively added adhesion promoters may remain unreacted in the cured product even after the photosensitive resin composition has hardened, potentially adversely affecting the physical properties of the cured product. Depending on the substrate, even a small amount may be effective, so it is appropriate to use it within a range that does not cause a decrease in physical properties. The proportion of adhesion promoter used is preferably 15% by mass or less, and more preferably 5% by mass or less, in the photosensitive resin composition.

[0039] The photosensitive resin composition of the present invention may further contain a sensitizer to absorb ultraviolet light and provide the absorbed light energy to the photocationic polymerization initiator. Preferred sensitizers include, for example, thioxanthones and anthracene compounds having alkoxy groups at the 9th and 10th positions (9,10-dialkoxyanthracene derivatives). Examples of the alkoxy group include alkoxy groups having 1 to 4 carbon atoms, such as methoxy, ethoxy, propoxy, and butoxy groups. The 9,10-dialkoxyanthracene derivative may further contain substituents. Examples of substituents include halogen atoms such as fluorine, chlorine, bromine, and iodine atoms, alkyl groups having 1 to 4 carbon atoms such as methyl, ethyl, and propyl groups, alkyl sulfonate ester groups, and alkyl carboxylate ester groups. Examples of alkyl groups in alkyl sulfonate ester groups and alkyl carboxylate esters include alkyl groups having 1 to 4 carbon atoms, such as methyl, ethyl, and propyl. The substitution position of these substituents is preferably at the 2nd position.

[0040] Specific examples of thioxanthones include 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2-chlorothioxanthone, 2-isopropylthioxanthone, 2,4-diisopropylthioxanthone, and 2-isopropylthioxanthone, with 2,4-diethylthioxanthone (trade name Kayacure DETX-S, manufactured by Nippon Kayaku Co., Ltd.) or 2-isopropylthioxanthone being preferred.

[0041] Examples of 9,10-dialkoxyanthracene derivatives include 9,10-dimethoxyanthracene, 9,10-diethoxyanthracene, 9,10-dipropoxyanthracene, 9,10-dibutoxyanthracene, 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, and 9,10-dimethoxyanthracene-2-carboxylate methyl ester.

[0042] These sensitizers can be used individually or in combination of two or more. The use of 2,4-diethylthioxanthone and 9,10-dimethoxy-2-ethylanthracene is most preferred. Since the sensitizer components are effective even in small amounts, their usage ratio is preferably 30% by mass or less, and more preferably 20% by mass or less, relative to component (B).

[0043] If it is necessary to reduce the adverse effects of ions derived from component (B), the photosensitive resin composition of the present invention may be supplemented with ion catchers such as alkoxyaluminum compounds including trismethoxyaluminum, trisethoxyaluminum, trisisopropoxyaluminum, isopropoxydiethoxyaluminum, and trisbutoxyaluminum; phenoxyaluminum compounds including trisphenoxyaluminum and trisparamethylphenoxyaluminum; trisacetoxyaluminum, trisstearatoaluminum, trisbutyratoaluminum, trispropionatoaluminum, trisacetylacetonatoaluminum, tristrifluoroacetylacetonatoaluminum, trisethylacetoacetatoaluminum, diacetylacetonatodipivaloylmethanatoaluminum, and organoaluminum compounds such as diisopropoxy(ethylacetoacetato)aluminum. These ion catchers can be used alone or in combination of two or more. The amount of these ion catchers may be 10% by mass or less relative to the total solid content (all components excluding the solvent) of the photosensitive resin composition of the present invention.

[0044] The photosensitive resin composition of the present invention may also contain a leveling agent for the purpose of further reducing surface tension and improving coating properties. Examples of leveling agents include fluorine-based leveling agents (Futergent 100, 300, 251, 222F, 710FL, 601AD: manufactured by Neos Co., Ltd.), silicone-based leveling agents (Disparon 711EF, 1761, LS-001, LS-460: manufactured by Kusumoto Kasei Co., Ltd.), and acrylic-based leveling agents (Disparon 1970, 230, LF-1980: manufactured by Kusumoto Kasei Co., Ltd.). These leveling agents can be used individually or in combination of two or more. The amount used is preferably 0.01% to 1% relative to the total solid content (all components excluding the solvent) of the photosensitive resin composition of the present invention.

[0045] The photosensitive resin composition of the present invention may further contain various additives as needed, such as thermoplastic resins, colorants, thickeners, and defoamers. Examples of thermoplastic resins include polyethersulfone, polystyrene, and polycarbonate. Examples of colorants include phthalocyanine blue, phthalocyanine green, iodine green, crystal violet, titanium dioxide, carbon black, and naphthalene black. Examples of thickeners include olbene, bentonite, and montmorillonite. Examples of defoamers include silicone-based, fluorine-based, and polymer-based defoamers. When using these additives, the amount used in the photosensitive resin composition of the present invention is, for example, 30% by mass or less of each. This amount can be appropriately increased or decreased depending on the intended use.

[0046] The photosensitive resin composition of the present invention may contain inorganic fillers such as barium sulfate, barium titanate, silicon dioxide, amorphous silica, talc, clay, magnesium carbonate, calcium carbonate, aluminum oxide, aluminum hydroxide, and mica powder. The amount of inorganic filler added may be 60% by mass or less in the photosensitive composition of the present invention.

[0047] The photosensitive resin composition of the present invention can be prepared simply by mixing and stirring the essential components (A), (B), and (C) with solvents and various additives as needed, using a conventional method. Dispersion and mixing may also be performed using a disperser such as a dissolver, homogenizer, or three-roll mill, if necessary. Furthermore, filtration may be performed after mixing using a mesh, membrane filter, or the like.

[0048] The photosensitive resin composition of the present invention is preferably used in a solution with added solvent. To use the photosensitive resin composition of the present invention dissolved in a solvent, first, the photosensitive resin composition of the present invention can be applied to a metal substrate such as silicon, aluminum, or copper, a ceramic substrate such as lithium tantalate, glass, silicon oxide, or silicon nitride, or a substrate such as polyimide or polyethylene terephthalate, using a spin coater to a thickness of 0.1 to 1,000 μm. Next, the solvent is removed by heating at 60 to 130°C for about 5 to 60 minutes to form a photosensitive resin composition layer, and then pre-baking is performed before a mask having a predetermined pattern is placed on top and ultraviolet light is irradiated. Next, after heat treatment (post-exposure baking) at 50 to 130°C for about 1 to 50 minutes, the unexposed areas can be developed using a developer at room temperature to 50°C for about 1 to 180 minutes to form a pattern. Finally, by heat treatment (hard bake) at 130 to 230°C, a cured product satisfying various properties can be obtained. These processing conditions are not limiting and are typical examples. As the developer, for example, organic solvents such as γ-butyrolactone, triethylene glycol dimethyl ether, or propylene glycol monomethyl ether acetate, or a mixture of the above organic solvent and water can be used. Developing equipment such as paddle type, spray type, or shower type may be used. Ultrasonic irradiation may be performed as needed. A preferred metal substrate when using the photosensitive resin composition of the present invention is aluminum.

[0049] The photosensitive resin composition of the present invention can be made into a dry film resist by applying the composition onto a base film using a roll coater, die coater, knife coater, bar coater, gravure coater, etc., drying it in a drying oven set to 45 to 100°C, removing a predetermined amount of solvent, and laminating a cover film, etc., as needed. In this case, the thickness of the resist on the base film can be adjusted to 2 to 100 μm. For the base film and cover film, for example, films such as polyester, polypropylene, polyethylene, TAC, and polyimide can be used. These films may be films that have been released using a silicone-based release agent or a non-silicone-based release agent, etc., as needed. To use this dry film resist, for example, the cover film can be peeled off and transferred to a substrate using a hand roll or laminator, etc., at a temperature of 40 to 100°C and a pressure of 0.05 to 2 MPa, and then exposed, baked after exposure, developed, and heat-treated in the same way as the photosensitive resin composition dissolved in the solvent.

[0050] As described above, supplying the photosensitive resin composition as a dry film eliminates the need for coating and drying on a support. This makes it possible to form cured patterns using the photosensitive resin composition of the present invention more easily.

[0051] When used as a MEMS package or semiconductor package, the photosensitive resin composition of the present invention can be used by coating the MEMS or semiconductor device with the composition, or by creating a hollow structure around the MEMS or semiconductor device. As substrates for MEMS and semiconductor packages, substrates are used in which thin metal films such as aluminum, gold, copper, chromium, and titanium are deposited on silicon wafers of various shapes by sputtering or vapor deposition to a thickness of 10 to 5,000 Å, and the metal is micro-processed by etching or the like. In some cases, an inorganic protective film of silicon oxide or silicon nitride may also be deposited to a thickness of 10 to 10,000 Å. Next, the MEMS or semiconductor device is fabricated or installed on the substrate, and it is necessary to coat or create a hollow structure to isolate the device from the outside air. When coating with the photosensitive resin composition of the present invention, this can be done by the method described above. Furthermore, when fabricating a hollow structure, a partition wall is formed on the substrate using the method described above, and then a dry film is laminated on top of it using the method described above and patterned to form a lid on the partition wall, thereby creating a hollow package structure. After fabrication, MEMS package components and semiconductor package components that satisfy various properties can be obtained by heat treatment at 130 to 200°C for 10 to 120 minutes as needed.

[0052] Furthermore, "package" refers to a sealing method or product used to block the ingress of gases and liquids from the outside air in order to maintain the stability of substrates, wiring, elements, etc. In this specification, "package" refers to hollow packages for packaging devices with moving parts such as MEMS or oscillators such as SAW devices, as well as surface protection and resin sealing performed to prevent deterioration of semiconductor substrates, printed circuit boards, wiring, etc. In addition, "wafer-level package" as referred to in this specification refers to a packaging method or product in which protective film, terminals, wiring processing, and packaging are performed on a wafer before cutting it into chips.

[0053] The photosensitive resin composition of the present invention exhibits a high elastic modulus. Therefore, this photosensitive resin composition can be used, for example, in the manufacture of MEMS (micro-electromechanical systems) components, micromachine components, microfluidic components, μ-TAS (micro-total analytical systems) components, inkjet printer components, microreactor components, conductive layers, LIGA components, molds and stamps for micro-injection molding and thermal embossing, screens or stencils for micro-printing applications, MEMS package components, semiconductor package components, BioMEMS and biophotonic devices, and printed circuit boards. It is particularly useful in the manufacture of MEMS package components and semiconductor package components. [Examples]

[0054] The present invention will be described below with reference to examples. These examples are merely illustrative to illustrate the present invention, and the scope of the present invention is not limited to the examples shown below.

[0055] Synthesis Example 1 (Synthesis of Component (A) (Acid-modified polyfunctional epoxy resin (a-2))) In a 5L flask, 429.5 parts of cyclopentanone as the reaction solvent and 868.0 parts of jER-4004P (manufactured by Mitsubishi Chemical Corporation, bisphenol F type epoxy resin, epoxy equivalent 868 g / eq.) as component (x) were charged and heated to 120°C to dissolve the resin. To this resin solution, 134.1 parts of dimethylolpropionic acid as component (y) and 1.43 parts of triphenylphosphine as a reaction catalyst were added and the mixture was reacted at 120°C for 26 hours. After confirming that the acid value of the reaction solution was 7 mg·KOH / g or less, 304.3 parts of tetrahydrophthalic anhydride and 272.5 parts of cyclopentanone were added as component (z) and the mixture was reacted at 80°C for 8 hours to obtain a cyclopentanone solution of component (a-2) (acid-modified polyfunctional epoxy resin (A-8)) with a solid content acid value of 99.6 mg·KOH / g.

[0056] Examples 1 to 15 and Comparative Examples 1 to 11 (Preparation of Photosensitive Resin Compositions) According to the proportions (in parts by mass) listed in Tables 1 to 4, the essential components (A) to (C) and other optional components were stirred and mixed in a flask with a stirrer at 60°C for 2 hours to obtain the photosensitive resin compositions of the present invention and comparative examples. Note that component (a-2) (acid-modified polyfunctional epoxy resin (A-8)) obtained in Synthesis Example 1 was a cyclopentanone solution; however, when used in the composition, the solvent was evaporated and then redissolved in the solvent in the composition before use. The proportions listed in Table 1 indicate the mass of the solid content.

[0057] (A-1) to (F) in Tables 1 to 4 are as follows: (A-1): Bisphenol A novolac type epoxy resin (product name: KM-N-LCL, manufactured by Nippon Kayaku Co., Ltd., softening point 85℃, epoxy equivalent: 210g / eq.) (A-2): Biphenyl aralkyl epoxy resin (Product name: NC-3000, manufactured by Nippon Kayaku Co., Ltd., softening point 57°C, epoxy equivalent 276 g / eq.) (A-3): Cresol novolac type epoxy resin (product name: EOCN-104S, manufactured by Nippon Kayaku Co., Ltd., softening point 90°C, epoxy equivalent 220 g / eq.) (A-4): Trisphenolmethane type epoxy resin (product name: EPPN-502, manufactured by Nippon Kayaku Co., Ltd., softening point 65℃, epoxy equivalent 170g / eq.) (A-5): Trifunctional epoxy resin (Product name: NC-6300H, manufactured by Nippon Kayaku Co., Ltd., softening point 65℃, epoxy equivalent 210g / eq.) (A-6): Alicyclic epoxy resin (Product name: DE-102, manufactured by ENEOS Corporation, softening point: 86℃, epoxy equivalent weight: 107g / eq.) (A-7): Bisphenol F type epoxy resin (product name: JER-4007P, manufactured by Nippon Kayaku Co., Ltd., softening point 108℃, epoxy equivalent: 2500g / eq.) (A-8): Acid-modified polyfunctional epoxy resin obtained in Synthesis Example 1 (A-8) (softening point: 70°C) (A-9): Liquid bisphenol A type epoxy resin (product name: RE-310S, manufactured by Nippon Kayaku Co., Ltd., epoxy equivalent 180 g / eq.) (A-10): Phenol novolac type epoxy resin (Product name: RE-305S, manufactured by Nippon Kayaku Co., Ltd., epoxy equivalent 173 g / eq.) (A-11): Liquid triazine-type epoxy resin (product name: TEPIC-VL, manufactured by Nissan Chemical Corporation, epoxy equivalent weight 190 g / eq.) (A-12): Liquid aliphatic epoxy resin (Product name: EX-321L, manufactured by Nagase ChemteX Corporation, epoxy equivalent weight 130 g / eq.) (A-13): Liquid oxetane resin (product name: OXT-221, manufactured by Toagosei Co., Ltd., oxetane equivalent 105g / eq.) (A-14): Alicyclic epoxy resin (Product name: Liquid Celloxide 2021P, manufactured by Daicel Corporation, epoxy equivalent 130 g / eq.) (A-15): Liquid bisphenol F type epoxy resin (Product name: YDF-8170C, manufactured by Nippon Steel Chemical & Material Co., Ltd., epoxy equivalent weight 170g / eq.) (B-1): Product name: Irgcure290, manufactured by BASF (C-1): Triphenylphosphine oxide (Trade name: TPPO, manufactured by Hokko Chemical Co., Ltd.) (C-2): Hindered amine compound (trade name: Tinuvin 770 DF, manufactured by BASF) (C-3): Weak acid-generating photocationic polymerization initiator (product name: SP-152, manufactured by ADEKA Corporation) (C-4): Weak acid-generating photocationic polymerization initiator (product name: CPI-300CS, manufactured by Sunapro Co., Ltd.) (D): Coupling agent (product name: S-510, manufactured by JNC Corporation) (E): Leveling agent (Product name: Futergent 222F, manufactured by Neos Co., Ltd.) (F): Solvent (Product name: 2-Butanone, manufactured by Junsei Chemical Co., Ltd.)

[0058] (Coating, drying, exposure, and development of the photosensitive resin layer) Each photosensitive resin composition obtained in Examples 1 to 15 and Comparative Examples 1 to 11 was coated onto a silicon wafer using a spin coater, and the solvent was dried to obtain a 20 μm photosensitive resin composition layer. This photosensitive resin composition layer was pre-baked on a hot plate at 65°C for 4 minutes. Then, pattern exposure (soft contact, i-line) was performed using an i-line exposure apparatus (mask aligner: Ushio Inc.), followed by exposure and baking on a hot plate at 95°C for 6 minutes, and development was performed using a immersion method with propylene glycol monomethyl ether acetate at 23°C for 5 minutes to obtain a cured resin pattern on a substrate (silicon wafer).

[0059] (Resolution evaluation of photosensitive resin compositions) In the pattern exposure on the silicon (Si) wafer substrate described above, the width of the narrowest pattern in close contact with the substrate was confirmed by microscope within the resist pattern resolved with a 1:1 line-and-space ratio without residue, and the resolution of the photosensitive resin composition was evaluated according to the following evaluation criteria. The results are shown in Tables 1 to 4. Evaluation Criteria ○ (Good): The narrowest pattern width is 10 μm or less. × (Defective): The narrowest pattern width exceeded 10 μm, or no pattern was formed.

[0060] (Evaluation of adhesion strength of photosensitive resin composition to Si) The adhesion strength referred to here is the shear strength (shear strength) at which the pattern peels off the substrate when force is applied from the side of the pattern using a shear tool. A higher value indicates stronger adhesion between the substrate and the resin composition, which is preferable. Specifically, a block-shaped resist pattern of 100 μm × 100 μm (film thickness of 20 μm) was formed on a silicon wafer substrate with the optimal exposure amount confirmed above. A bonding tester (manufactured by Resca) was used to measure the breaking load when a load was applied from the side at a height of 3 μm from the substrate at a speed of 50 μm / sec using a 100 μm shear tool, and the adhesion strength was evaluated according to the evaluation criteria below. The results are shown in Tables 1 to 4. Evaluation Criteria ○: Adhesion strength of 45gf or higher ×: Adhesion strength less than 45gf

[0061] (Condensation test of photosensitive resin composition) Using a 6-inch silicon wafer, the same patterning procedure as described above was performed on each photosensitive resin composition obtained in Examples 1 to 15 and Comparative Examples 1 to 11. However, in this case, a grid-shaped photomask was used to create a frame-like area with a width of 1 mm and a space of 3 mm vertically and horizontally. After patterning, a 300 μm thick 6-inch Tempax glass wafer (manufactured by Schott Japan Ltd.) substrate was bonded onto the pattern by heat and pressure (heat and pressure conditions: 150°C, 10 kN, 3 minutes) to obtain a sample for condensation testing with a cavity. This sample was heat-cured at 180°C for 1 hour using a convection oven to prepare an evaluation sample. The obtained sample was subjected to a heat cycle test consisting of 10 sets of heating on a 260°C hot plate for 3 minutes and cooling on a 23°C water-cooled cooling plate for 2 minutes. After this, the presence or absence of condensation on the glass substrate surface in the cavity was checked under a microscope and evaluated according to the following evaluation criteria. The results are shown in Tables 1 to 4. Evaluation Criteria ○: No condensation observed ×: Condensation was observed.

[0062] [Table 1]

[0063] [Table 2]

[0064] [Table 3]

[0065] [Table 4]

[0066] From the results in Tables 1 to 4, it is clear that the photosensitive resin compositions of the present invention (Examples 1 to 15) are superior to the photosensitive resin compositions of Comparative Examples 1 to 11 in terms of resist resolution, adhesion to Si substrates, and condensation prevention effect. [Industrial applicability]

[0067] The photosensitive resin composition of the present invention can form patterns with high adhesion to substrates and has a high condensation prevention effect, thus providing resin molded products that are resistant to durability tests such as reflow tests, particularly in fields such as MEMS components, MEMS package components, and semiconductor packages.

Claims

1. A photosensitive resin composition comprising a cationic curable resin (A), a photocationic polymerization initiator (B), and a quencher (C), wherein the cationic curable resin (A) contains a polyfunctional epoxy resin (a-1) with a softening point of 50°C or higher, and contains 60% by mass or more of the polyfunctional epoxy resin (a-1) with a softening point of 50°C or higher in the cationic curable resin (A), or contains 60% by mass or more of the total amount of the polyfunctional epoxy resin (a-1) with a softening point of 50°C or higher and an acid-modified product of the polyfunctional epoxy resin (a-2) with a softening point of 50°C or higher in the cationic curable resin (A), and the quencher (C) is of the following formula (1) 【Chemistry 1】 A photosensitive resin composition containing a compound represented by the formula (wherein R1 to R3 each independently represent an alkyl group or a phenyl group).

2. The photosensitive resin composition according to claim 1, wherein R1 to R3 are phenyl groups.

3. A dry film resist comprising the photosensitive resin composition according to claim 1 or 2.

4. A cured product of the photosensitive resin composition according to claim 1 or 2.

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