Photosensitive resin composition and cured product thereof

Abstract

To provide a photosensitive resin composition from which a cured product having high elastic modulus at normal temperature and high temperature and excellent resistance against a temperature and a pressure applied in a sealing step in a package manufacturing step can be obtained.SOLUTION: There are provided: a photosensitive resin composition which contains a polyfunctional epoxy resin (A) having an aromatic ring and three or more epoxy groups, an alicyclic epoxy resin (B) represented by the following formula (1) or (2), wherein X represents CR17R18, and R1 to R18 each independently represent a hydrogen atom, an alkyl group or an alkoxy group, and a photo-cationic polymerization initiator (C); and a cured product of the same.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 which has a high elastic modulus at high temperatures and excellent adhesion to various substrates. [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] When photoresist cured products are used as components in semiconductor packages, for example, if the manufacturing process of the semiconductor package includes a step of resin encapsulating the photoresist cured product together with other components, the cured product is required to have a high elastic modulus so that it can maintain its shape during resin encapsulation. In particular, in recent years, with the miniaturization and weight reduction of devices, there has been an increasing demand for smaller and thinner semiconductor packages, so a higher elastic modulus is required for the photoresist cured film.

[0005] Patent Document 1 discloses a photosensitive resin composition comprising a compound having a specific structure with a triazine ring, a polyfunctional epoxy resin of a specific structure, and a photocationic polymerization initiator. The examples in this document describe that the cured product of the photosensitive resin composition has high elastic modulus at high temperatures and high adhesion strength to substrates other than silicon wafers. However, given the increasing demand for higher elastic modulus, the content described in this patent is insufficient, and further improvement in elasticity was necessary. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Patent No. 7085791 [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 has a high elastic modulus and can produce a cured product with excellent resistance to temperature and pressure during the sealing process in the package manufacturing process. [Means for solving the problem]

[0008] As a result of diligent research, the present inventors have found that a photosensitive resin composition containing a polyfunctional epoxy resin having an aromatic ring and three or more epoxy groups, an alicyclic epoxy resin with a specific structure, and a photocationic polymerization initiator can solve the above problems, and have completed the present invention.

[0009] The present invention relates to the following embodiments. [1] A polyfunctional epoxy resin (A) having an aromatic ring and three or more epoxy groups, the following formula (1) or (2)

[0010] [ka]

[0011] (In the formula, X represents CR17R18, and R1 to R 18 (Each of these independently represents a hydrogen atom, an alkyl group, or an alkoxy group.) A photosensitive resin composition containing an alicyclic epoxy resin (B) represented by [formula] and a photocationic polymerization initiator (C). [2] The photosensitive resin composition according to paragraph [1], wherein the content of the alicyclic epoxy resin (B) is 10% by mass or more and less than 100% by mass relative to the polyfunctional epoxy resin (A) having an aromatic ring and three or more epoxy groups. [3]R1 to R 18 The photosensitive resin composition described in the preceding paragraph [1], wherein is a hydrogen atom. [4] The photosensitive resin composition according to item [1] above, wherein the polyfunctional epoxy resin (A) having an aromatic ring and three or more epoxy groups has a softening point of 50°C or higher. [5] A dry film resist comprising the photosensitive resin composition described in any one of the preceding paragraphs [1] to [4]. [6] A cured product of a photosensitive resin composition as described in any one of the preceding paragraphs [1] to [4]. [Effects of the Invention]

[0012] The cured product of the photosensitive resin composition of the present invention has a high elastic modulus and excellent resistance to the temperature and pressure applied during sealing in the package manufacturing process. Therefore, this photosensitive resin composition is suitably used 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 comprises a polyfunctional epoxy resin (A) having an aromatic ring and three or more epoxy groups, and the above formula (1) or (2) It contains an alicyclic epoxy resin (B) represented by [formula] and a photocationic polymerization initiator (C).

[0014] The functional epoxy resin (A) (hereinafter simply referred to as "component (A)") contained in the photosensitive resin composition of the present invention is not particularly limited as long as it is an epoxy resin having an aromatic ring and 3 or more epoxy groups in one molecule. By containing the epoxy resin having an aromatic ring and 3 or more epoxy groups, the heat resistance and elastic modulus of the photosensitive resin composition are improved.

[0015] Examples of component (A) include novolac-type epoxy resins obtained by reacting novolacs, which are obtained by reacting phenols (phenol, alkyl-substituted phenol, naphthol, alkyl-substituted naphthol, dihydroxybenzene, dihydroxynaphthalene, etc.) with formaldehyde under an acidic catalyst, with halohydrins such as epichlorohydrin and methylepichlorohydrin. Specific examples of such component (A) 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. Component (A) may be used alone or in combination of two or more in the photosensitive resin composition of the present invention.

[0016] The content of component (A) in the photosensitive resin composition of the present invention is preferably 20 to 90 mass%, more preferably 40 to 80 mass%, in the solid content (components other than the solvent) of the photosensitive resin composition. The softening point of component (A) contained in the photosensitive resin composition of the present invention is preferably 50 to 120°C, more preferably 60 to 110°C, because if the softening point of the resin component contained in the photosensitive resin composition is low, tack (stickiness) occurs on the surface of the resin layer (or dry film resist) formed using the photosensitive resin composition, and sticking of the photomask tends to occur. The softening point in the present invention is a value measured by a method conforming to the ring and ball method of JIS K7234. The epoxy equivalent of component (A) contained in the photosensitive resin composition of the present invention is preferably 100 to 500 g / eq., more preferably 200 to 350 g / eq. The epoxy equivalent in the present invention is a value measured by a method in accordance with JIS K7236.

[0017] The photosensitive resin composition of the present invention contains an alicyclic epoxy resin (B) having a specific structure represented by the above formula (1) or formula (2) (hereinafter simply referred to as "component (B)"). X in formula (1) and formula (2) represents CR17R18, and R1 to R 18 each independently represent a hydrogen atom, an alkyl group or an alkoxy group. R1 to R 18 each are preferably a hydrogen atom or an alkyl group, more preferably a hydrogen atom.

[0018] Preferable specific examples of component (B) include, for example, dodecahydro-2,6-methano-2H-oxireno[3',4']cyclopenta[1',2':6,7]naphtho[2,3-b]oxirene (product name: DE-102 (ENEOS Corporation), an alicyclic epoxy resin represented by formula (1) in which R1 to R 18 are hydrogen atoms), dodecahydro-2,6:3,5-dimethano-2H-oxireno[3',4']cyclopenta[1',2':6,7]naphtho[2,3-b]oxirene (DE-103 (ENEOS Corporation), an alicyclic epoxy resin represented by formula (2) in which R1 to R 14 , R 17 and R 18 are hydrogen atoms).

[0019] Component (B) may be used alone in the photosensitive resin composition of the present invention, or two or more thereof may be used in combination, and the alicyclic epoxy resin represented by formula (1) and the alicyclic epoxy resin represented by formula (2) may be used in combination. The content of component (B) in the photosensitive resin composition of the present invention is usually 1 to 100 mass%, preferably 5 to 100 mass%, more preferably 15 to 100 mass%, relative to component (A).

[0020] The photosensitive resin composition of the present invention contains (C) a photocationic polymerization initiator (hereinafter simply referred to as "component (C)"). The photosensitive resin composition of the present invention contains component (C), which 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 cationic polymerizable compounds such as epoxy resins. Component (C) 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.

[0021] 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).

[0022] 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.

[0023] Of these (C) components, in the present invention, aromatic sulfonium complex salts that have high vertical rectangular processability and high thermal stability are preferred in the photosensitive image forming process, and more preferably are a mixture of aromatic sulfonium hexafluoroantimonates containing 4-{4-(2-chlorobenzoyl)phenylthio}phenylbis(4-fluorophenyl)sulfonium hexafluoroantimonate, 4-thiophenyldiphenylsulfonium hexafluoroantimonate, or tris[4-(4-acetylphenyl)sulfonylphenyl]sulfonium tetrakis(2,3,4,5,6-pentafluorophenyl)borate.

[0024] Component (C) may be used alone or in combination of two or more in the photosensitive resin composition of the present invention. Because component (C) has the effect of absorbing light, when a large amount of component (C) is used (for example, more than 15% by mass) in the case of a thick film (for example, 50 μm or more), it tends to be difficult to sufficiently transmit light to the depths during curing, while when a small amount is used (for example, less than 3% by mass), it is not easy to obtain a sufficient curing rate. In the case of a thin film, a small amount of component (C) (for example, 1% by mass or more) is added to exhibit sufficient performance. Conversely, when a large amount of component (C) is used in the case of a thin film, there is no problem with light transmission to the depths, but it is not economical because it requires the use of an unnecessarily large amount of an expensive initiator. From these points of view, the content of component (C) in the photosensitive resin composition of the present invention is usually 0.1 to 10% by mass, preferably 0.5 to 5% by mass, relative to the total mass of components (A) and (B). In another embodiment, the proportion of component (C) in the photosensitive resin composition of the present invention may be 0.1 to 5% by mass, or 0.5 to 10% by mass, relative to the total mass of components (A) and (B). However, if the molar extinction coefficient of component (C) at a wavelength of 300 to 380 nm is high, it is necessary to adjust the proportion to an appropriate level depending on the film thickness when using the photosensitive resin composition.

[0025] The photosensitive resin composition of the present invention may also contain epoxy compound (D) other than component (A) and component (B) (hereinafter simply referred to as "component (D)"). Examples of component (D) include bifunctional or less aromatic glycidyl ether epoxy compounds (e.g., bisphenol A type glycidyl ether, bisphenol F type glycidyl ether, etc.); bifunctional or less 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 (D) may be used alone or in combination of two or more types.

[0026] Component (D) is used to improve the reactivity of the photosensitive resin composition of the present invention and the physical properties of the cured film. Component (D) is mostly liquid, and if more than 20% by mass of liquid component (D) is added to the solid content of the photosensitive resin composition, tack (stickiness) will occur on the surface of the resin layer (or dry film resist) formed using the photosensitive resin composition, making photomask sticking more likely. Furthermore, if component (D) is added in excess, it is thought that the elastic modulus of the cured product of the photosensitive resin composition will decrease. Therefore, the content of component (D) is preferably 10% by mass or less, and more preferably 7% by mass or less, relative to the total mass of components (A) and (B).

[0027] The photosensitive resin composition of the present invention may contain a solvent to reduce the viscosity of the composition and improve its applicability to various substrates. Any organic solvent commonly used in inks, paints, etc., that is capable of dissolving each component of the photosensitive resin composition can be used without particular limitations. 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. These solvents can be used individually or in mixtures of two or more.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] The photosensitive resin composition of the present invention may also contain a sensitizer that absorbs ultraviolet light and provides 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 have 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.

[0033] 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.

[0034] 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.

[0035] 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 (C).

[0036] If it is necessary to reduce the adverse effects of ions derived from component (C) in the photosensitive resin composition of the present invention, ion catchers such as alkoxyaluminum such as trismethoxyaluminum, trisethoxyaluminum, trisisopropoxyaluminum, isopropoxydiethoxyaluminum, and trisbutoxyaluminum, phenoxyaluminum such as trisphenoxyaluminum and trisparamethylphenoxyaluminum, trisacetoxyaluminum, trisstearatoaluminum, trisbutyratoaluminum, trispropionatoaluminum, trisacetylacetonatoaluminum, tristrifluoroacetylacenatoaluminum, trisethylacetoacetatoaluminum, diacetylacetonatodipivaloylmethanatoaluminum, and organoaluminum compounds such as diisopropoxy(ethylacetoacetato)aluminum may be added. These ion catchers can be used alone or in combination of two or more. The amount added 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.

[0037] The photosensitive resin composition of the present invention may further contain a quencher for the purpose of improving storage stability and preventing the diffusion of acid generated from the photocationic polymerization initiator. Examples of quenchers include organic amine compounds (primary, secondary, and tertiary aliphatic amines, aromatic amines, and heterocyclic amines), and organophosphorus compounds (triphenylphosphine (TPP: manufactured by Hokko Chemical Co., Ltd.), triphenylphosphine oxide (TPPO: manufactured by Hokko Chemical Co., Ltd.)). These quenchers can be used individually or in combination of two or more. The amount used is preferably 0.01% to 1% relative to component (C).

[0038] 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.

[0039] The photosensitive resin composition of the present invention may further contain various additives as needed, such as thermoplastic resins, colorants, thickeners, defoamers, and leveling agents. 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 defoaming agents include silicone-based, fluorine-based, and polymer-based defoaming agents. When using these additives, the amount used in the photosensitive resin composition of the present invention should be, for example, 30% by mass or less of each. This amount can be increased or decreased as appropriate depending on the intended use.

[0040] 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.

[0041] 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.

[0042] 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, to a thickness of 0.1 to 1000 μm using a spin coater. 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.

[0043] 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.

[0044] 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.

[0045] When used as a MEMS package or semiconductor package, the photosensitive resin composition of the present invention can be used by coating a 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 of aluminum, gold, copper, chromium, titanium, etc., are deposited on silicon wafers of various shapes by sputtering or vapor deposition to a thickness of 10 to 5000 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 10000 Å. Next, a 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. When creating a hollow structure, a partition wall is formed on the substrate by the method described above, and then a dry film is laminated on top of it by the method described above, and patterned to form a lid on the partition wall, thereby creating a hollow package structure. Furthermore, 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.

[0046] 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.

[0047] 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]

[0048] The present invention will be described below with reference to examples. These examples are merely illustrative for suitably illustrating the present invention, and the scope of the present invention is not limited to the examples shown below.

[0049] Examples 1 to 11, Comparative Examples 1 to 8 (Preparation of photosensitive resin compositions) According to the proportions (in parts by mass) listed in Tables 1 to 3, essential components (A) to (C) and other optional components were mixed in a flask equipped with a stirrer at 60°C for 2 hours to obtain the photosensitive resin compositions of the present invention and comparative compositions.

[0050] (Preparation of dry film resist) These photosensitive resin composition solutions were uniformly applied to a 38 μm thick polyethylene terephthalate (PET) film (base film, manufactured by Fujimori Kogyo Co., Ltd.) using a coater, and dried in a hot air convection dryer at 80°C for 2 minutes and then at 100°C for 2 minutes. After that, the release-treated side of a cover film (release-treated 38 μm thick PET film, manufactured by Mitsubishi Chemical Polyester Films Co., Ltd.) was laminated onto the dried coating surface to obtain a laminate (dry film resist) with a photosensitive resin composition layer thickness of 20 μm.

[0051] (Evaluation of the heat resistance of the cured product) The dry film resist obtained above was exposed through a mask pattern with an exposed area of 4 mm × 90 mm at 150 to 1,000 mJ / cm 2 of irradiation dose (i-line exposure apparatus, mask aligner: manufactured by Ushio Inc.). Thereafter, heating was performed on a hot plate at 95°C for 5 to 15 minutes, followed by development with PGMEA (propylene glycol monomethyl ether acetate) for 6 minutes to produce a cured product. Using a DMA measurement apparatus (RSA-G2 manufactured by TA Instruments), the elastic moduli of the cured product obtained above at 50°C and 175°C were measured under the conditions of tensile mode, 1 Hz, and a ramp rate of 3°C / sec. The results are shown in Tables 1 to 3 below.

[0052]

Table 1

[0053]

Table 2

[0054]

Table 3

[0055] Note that (A-1) to (G) in Tables 1 and 2 are as follows respectively. (A-1): Bisphenol A novolac type epoxy resin (trade name: KM-N-LCL, manufactured by Nippon Kayaku Co., Ltd., softening point 85°C, epoxy equivalent: 210 g / eq.) (A-2): Cresol novolac type epoxy resin (trade name: EOCN-104S, manufactured by Nippon Kayaku Co., Ltd., softening point 90°C, epoxy equivalent 220 g / eq.) (A-3): Trade name XD-1000, manufactured by Nippon Kayaku Co., Ltd., softening point 74°C) (A-4): Trade name NC-7000L, manufactured by Nippon Kayaku Co., Ltd., softening point 85°C) (A-5): Cresol novolac type epoxy resin (product name: NC-6300H, manufactured by Nippon Kayaku Co., Ltd., softening point 65℃, epoxy equivalent 210g / eq.) (A-6): Trisphenolmethane type epoxy resin (product name: EPPN-502, manufactured by Nippon Kayaku Co., Ltd., softening point 65℃, epoxy equivalent 170g / eq.) (A-7): Tetraphenolethane type epoxy resin, product name GTR-1800, manufactured by Nippon Kayaku Co., Ltd., softening point 170℃, epoxy equivalent: 170g / eq.) (B-1): Alicyclic epoxy resin (product name: DE-102, manufactured by ENEOS Corporation, softening point: 86℃, epoxy equivalent: 107g / eq.) (B-2): Alicyclic epoxy resin (product name: DE-103, manufactured by ENEOS Corporation, softening point: 136℃, epoxy equivalent: 117g / eq.) (C-1): Tris[4-(4-acetylphenyl)sulfonylphenyl]sulfonium tetrakis(2,3,4,5,6-pentafluorophenyl) borate (trade name Irgcure290, manufactured by BASF) (D-1): Bisphenol A type epoxy resin (product name: YD-012, manufactured by Nippon Steel Chemical & Material Co., Ltd.) (D-2): Bisphenol F type epoxy resin (product name: JER-4004P, manufactured by Mitsubishi Chemical Corporation) (D-3): Anthracene-type epoxy resin (Product name: YX-8800, manufactured by Nippon Steel Chemical & Material Co., Ltd.) (D-4): Aliphatic epoxy resin (product name: EHPE-3150, manufactured by Daicel Corporation) (D-5): Alicyclic epoxy resin (product name: Celoxide 2021P, manufactured by Daicel Corporation) (D-6): Alicyclic epoxy resin (product name: THI-DE, manufactured by ENEOS Corporation) (E): Product name: Futergent 222F, manufactured by Neos Co., Ltd. (F):Product name TPPO, manufactured by Hokuko Chemical Co., Ltd. (G): Product name 2-Butanone, manufactured by Junsei Chemical Co., Ltd.

[0056] From the results in Table 1, it is clear that the photosensitive resin compositions of the present invention (Examples 1 to 11) have higher elastic moduli at 50°C and 175°C compared to the photosensitive resin compositions of Comparative Examples 1 to 8. [Industrial applicability]

[0057] The cured product of the photosensitive resin composition of the present invention has a high elastic modulus at high temperatures, making it particularly advantageous for cavity formation during molding in polymer capping applications such as SAW / BAW filters. As a result, it is possible to make the final product thinner, which is expected to broaden design flexibility.

Claims

1. A polyfunctional epoxy resin (A) having an aromatic ring and three or more epoxy groups, of the following formula (1) or (2) 【Chemistry 1】 (In the formula, X is CR １７ R １８ Represents R １ ~R １８ (Each of these independently represents a hydrogen atom, an alkyl group, or an alkoxy group.) A photosensitive resin composition comprising an alicyclic epoxy resin (B) represented by and a photocationic polymerization initiator (C), The polyfunctional epoxy resin (A) having the aromatic ring and three or more epoxy groups is a novolac-type epoxy resin. A photosensitive resin composition in which the content of the alicyclic epoxy resin (B) is 25 to 100% by mass relative to the polyfunctional epoxy resin (A) having an aromatic ring and three or more epoxy groups.

2. R １ ~R １８ The photosensitive resin composition according to claim 1, wherein is a hydrogen atom.

3. The photosensitive resin composition according to claim 1, wherein the softening point of the polyfunctional epoxy resin (A) having the aromatic ring and three or more epoxy groups is 50°C or higher.

4. A dry film resist comprising the photosensitive resin composition according to any one of claims 1 to 3.

5. A cured product of the photosensitive resin composition according to any one of claims 1 to 3.

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