Photocurable resin composition

Abstract

To provide a photocurable resin composition that yields a cured product having superior adhesion to wafers, the ability to suppress wafer detachment during dicing, and superior chemical resistance.SOLUTION: A photocurable resin composition for wafer coating comprises a curable resin, the curable resin comprises a compound having a carboxyl group and a polymerizable functional group, and the content of the compound having a carboxyl group and a polymerizable functional group is 9 pts.mass or more and 40 pts.mass or less based on 100 pts.mass of the photocurable resin composition.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a photocurable resin composition. [Background technology]

[0002] In recent years, a method called wafer-level CSP has been used as a mounting method for semiconductor components. In wafer-level CSP, since internal wiring using bonding wires is not performed, it is possible to make semiconductor components thinner, and since a dicing process is performed all at once after a packaging process for multiple semiconductor chips, it has excellent productivity. During the packaging process performed before the dicing process, a silicon wafer and a glass wafer are bonded together using a curable resin composition (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2018 / 030140 Summary of the Invention [Problem to be solved by the invention]

[0004] When a conventional curable resin composition is used, even if sufficient adhesive strength is exhibited when wafers (e.g., a silicon wafer and a glass wafer) are bonded together, peeling may occur on the wafer when a dicing process is performed thereafter, or when a process of treating with a chemical such as an amine solution (etching process, etc.) is performed, the chemical may corrode the cured product of the curable resin composition, or peeling may occur on the wafer. Therefore, there has been a demand for a curable resin composition that not only exhibits sufficient adhesive strength when wafers are bonded together, but also can suppress peeling of the wafer during dicing and has excellent chemical resistance (especially resistance to amine solutions).

[0005] An object of the present invention is to provide a photocurable resin composition which, when cured, has excellent adhesion to a wafer, can suppress peeling of the wafer during dicing, and has excellent chemical resistance. [Means for solving the problem]

[0006] Disclosure 1 relates to a photocurable resin composition to be applied to a wafer, the photocurable resin composition containing a curable resin, the curable resin containing a compound having a carboxy group and a polymerizable functional group, and the content of the compound having a carboxy group and a polymerizable functional group in 100 parts by mass of the photocurable resin composition is 9 parts by mass or more and 40 parts by mass or less. The present disclosure 2 is a photocurable resin composition to be applied to a wafer, the photocurable resin composition containing a curable resin, the curable resin containing a compound having a carboxy group and a polymerizable functional group, the number of carboxy groups in one molecule of the compound having the carboxy group and the polymerizable functional group being A, and the content ratio of the compound having the carboxy group and the polymerizable functional group in the curable resin being W. A (mass %), and the molecular weight of the compound having a carboxy group and a polymerizable functional group is M A The molecular weight of the components other than the compound having a carboxy group and a polymerizable functional group contained in the curable resin is M B The content ratio of components other than the compound having a carboxy group and a polymerizable functional group in the curable resin is W B (mass%), the carboxyl value Y in the entire curable resin calculated by the following formula (I) is 9.0 × 10 -5 Above 4.0×10 -4 The photocurable resin composition is as follows: Y = (A × W A ) / (M A ×W A +M B ×W B ) (I) The present disclosure 3 is the photocurable resin composition of the present disclosure 1 or 2, wherein the curable resin further contains a compound having a ring-opened caprolactone skeleton and a polymerizable functional group. The present disclosure 4 is the photocurable resin composition of the present disclosure 3, in which the content of the compound having a ring-opened caprolactone skeleton and a polymerizable functional group is 2.0 parts by mass or more and 10.0 parts by mass or less per part by mass of the compound having a carboxy group and a polymerizable functional group. The present disclosure 5 is a photocurable resin composition according to the present disclosure 1, 2, 3, or 4, which is used in a wafer bonding step in the manufacture of a CMOS image sensor. The present invention will be described in detail below. The photocurable resin composition according to Disclosure 1 is also referred to as the "photocurable resin composition of Invention 1," and the photocurable resin composition according to Disclosure 2 is also referred to as the "photocurable resin composition of Invention 2." Furthermore, matters common to the photocurable resin composition of Invention 1 and the photocurable resin composition of Invention 2 are not particularly specified or are described as the "photocurable resin composition of the present invention."

[0007] The present inventors have investigated the use of a specific content of a compound having a carboxy group and a polymerizable functional group in a photocurable resin composition to be applied to a wafer, and have found that a cured product having excellent adhesion to the wafer, suppressing peeling of the wafer during dicing, and excellent chemical resistance can be obtained, leading to the completion of the present invention 1. The present inventors have also investigated how to make the carboxyl value of the entire curable resin of a photocurable resin composition to be applied to a wafer fall within a specific range, and have found that it is possible to obtain a cured product that has excellent adhesion to the wafer, can suppress peeling of the wafer during dicing, and has excellent chemical resistance, thereby completing the present invention 2.

[0008] The photocurable resin composition of the present invention is used by coating it on a wafer. By applying the photocurable resin composition of the present invention to a wafer, the wafers (for example, a silicon wafer and a glass wafer) can be bonded together via the photocurable resin composition of the present invention. Examples of wafers onto which the photocurable resin composition of the present invention is applied include silicon wafers and glass wafers. The photocurable resin composition of the present invention is preferably applied to a wafer by spin coating. When the photocurable resin composition of the present invention is applied to a wafer by the above spin coating method, it is preferable to apply the composition at room temperature (15° C. or higher and 25° C. or lower) at a speed of 500 rpm or higher and 3000 rpm or lower.

[0009] The photocurable resin composition of the present invention contains a curable resin. The curable resin contains a compound having a carboxy group and a polymerizable functional group. By containing the compound having a carboxy group and a polymerizable functional group, the photocurable resin composition of the present invention has excellent adhesion to a wafer.

[0010] Examples of the polymerizable functional group contained in the compound having a carboxy group and a polymerizable functional group include a (meth)acryloyl group, a (meth)acrylamide group, a vinyl group, a thiol group, an epoxy group, etc. Among these, a (meth)acryloyl group is preferable. In this specification, the term "(meth)acryloyl" means acryloyl or methacryloyl, and the term "(meth)acrylic" means acrylic or methacrylic.

[0011] Specific examples of the compound having a carboxy group and a polymerizable functional group include 2-(meth)acryloyloxyethyl phthalic acid, 2-(meth)acryloyloxyethyl hexahydrophthalic acid, and the like.

[0012] In the photocurable resin composition of the present invention 1, the lower limit of the content of the compound having a carboxy group and a polymerizable functional group in 100 parts by mass of the photocurable resin composition is 9 parts by mass, and the upper limit is 40 parts by mass. When the content of the compound having a carboxy group and a polymerizable functional group is 9 parts by mass or more, the effect of suppressing peeling during dicing after bonding wafers (e.g., silicon wafer and glass wafer) is excellent. When the content of the compound having a carboxy group and a polymerizable functional group is 40 parts by mass or less, the obtained photocurable resin composition has excellent chemical resistance (particularly resistance to amine solution). In the photocurable resin composition of the present invention 1, the preferred lower limit of the content of the compound having a carboxy group and a polymerizable functional group in 100 parts by mass of the photocurable resin composition is 15 parts by mass, and the preferred upper limit is 35 parts by mass. In addition, in the photocurable resin composition of the present invention 2, the content of the compound having a carboxy group and a polymerizable functional group in 100 parts by mass of the photocurable resin composition is preferably 9 parts by mass, and the upper limit is preferably 40 parts by mass. When the content of the compound having a carboxy group and a polymerizable functional group is 9 parts by mass or more, the effect of suppressing peeling during dicing after bonding wafers (e.g., silicon wafer and glass wafer) is more excellent. When the content of the compound having a carboxy group and a polymerizable functional group is 40 parts by mass or less, the obtained photocurable resin composition has more excellent chemical resistance (particularly resistance to amine solution). In the photocurable resin composition of the present invention 2, the content of the compound having a carboxy group and a polymerizable functional group in 100 parts by mass of the photocurable resin composition is more preferably 15 parts by mass, and the upper limit is more preferably 35 parts by mass.

[0013] In the photocurable resin composition of the present invention 2, the lower limit of the carboxyl group value in the entire curable resin is 9.0 × 10 -5 , with an upper limit of 4.0×10 -4 The carboxyl value in the entire curable resin is 9.0×10 -5By satisfying the above, the effect of suppressing peeling during dicing after bonding wafers (e.g., silicon wafer and glass wafer) is excellent. -4 In the photocurable resin composition of the present invention 2, the preferred lower limit of the carboxyl value in the entire curable resin is 9.8×10 or less. -5 , with a preferred upper limit of 3.5×10 -4 and a more preferable lower limit is 1.0×10 -4 , and a more preferable upper limit is 3.0×10 -4 and a more preferable lower limit is 1.5×10 -4 It is. In the photocurable resin composition of the present invention 1, the preferred lower limit of the carboxyl group value in the entire curable resin is 9.0 × 10 -5 , the preferred upper limit is 4.0×10 -4 The carboxyl value in the entire curable resin is 9.0×10 -5 By satisfying the above condition, the effect of suppressing peeling during dicing after bonding wafers (e.g., silicon wafer and glass wafer) is excellent. -4 When the carboxyl value is 9.8×10 or less, the photocurable resin composition obtained has excellent chemical resistance (particularly resistance to amine solutions). In the photocurable resin composition of the present invention 1, the more preferable lower limit of the carboxyl value in the entire curable resin is 9.8×10 or less. -5 , and a more preferable upper limit is 3.5×10 -4 and a more preferable lower limit is 1.0×10 -4 , and more preferably the upper limit is 3.0×10 -4 and the particularly preferred lower limit is 1.5×10 -4 It is. The "carboxy value in the entire curable resin" is represented by Y, A, the number of carboxy groups in one molecule of the compound having a carboxy group and a polymerizable functional group, W, and Wc, respectively. A (mass %), and the molecular weight of the compound having a carboxy group and a polymerizable functional group is M A The molecular weight of the components other than the compound having a carboxy group and a polymerizable functional group contained in the curable resin (hereinafter, also referred to as "other curable resins") is M B The content ratio of the other curable resin in the curable resin is W B When expressed as % by mass, it can be calculated by the following formula (I). Y = (A × W A ) / (M A ×W A +M B ×W B ) (I) In this specification, the molecular weight is the molecular weight calculated from the structural formula for compounds with specific molecular structure, but may be expressed using the weight average molecular weight for compounds with a wide distribution of polymerization degrees and compounds with unspecified modified sites. In this specification, the "weight average molecular weight" is a value measured by gel permeation chromatography (GPC) and calculated in terms of polystyrene. Examples of columns used when measuring the weight average molecular weight calculated in terms of polystyrene by GPC include Shodex LF-804 (manufactured by Showa Denko KK). In addition, when the curable resin contains a plurality of types of compounds having a carboxy group and a polymerizable functional group, the above A and the above M A is the weight average value, and when the curable resin contains a plurality of types of the other curable resins, the above M B is the weighted average value.

[0014] The curable resin preferably further includes a compound having a ring-opened caprolactone skeleton and a polymerizable functional group as the other curable resin. By including the compound having a ring-opened caprolactone skeleton and a polymerizable functional group, the photocurable resin composition of the present invention has excellent adhesion to a wafer due to stress relaxation.

[0015] Examples of the polymerizable functional group contained in the compound having a ring-opened caprolactone skeleton and a polymerizable functional group include a (meth)acryloyl group, a (meth)acrylamide group, a vinyl group, a thiol group, an epoxy group, etc. Among these, a (meth)acryloyl group is preferred.

[0016] Specific examples of the compound having a ring-opened caprolactone skeleton and a polymerizable functional group include compounds represented by the following formula (1).

[0017] [ka]

[0018] In formula (1), R 1 represents a hydrogen atom or a methyl group, R 2 represents a group represented by the following formula (2-1), (2-2), or (2-3), and R 3 represents a structure derived from an optionally substituted dicarboxylic acid or anhydride thereof, X represents a ring-open structure of caprolactone, n is 1 or more and 5 or less, and Ep represents a structure derived from a di- or higher functional epoxy compound.

[0019] [ka]

[0020] In formulae (2-1), (2-2), and (2-3), * and ** represent bonding positions, and in formula (2-2), a is an integer of 1 or more and 8 or less, and in formula (2-3), b is an integer of 1 or more and 8 or less, c is an integer of 1 or more and 3 or less, and d is an integer of 1 or more and 8 or less. In formulae (2-1) and (2-3), of the bonding positions * and **, * is the bonding position with the (meth)acryloyloxy group in formula (1).

[0021] When the curable resin contains a compound having the ring-opening skeleton of caprolactone and a polymerizable functional group, the content of the compound having the ring-opening skeleton of caprolactone and a polymerizable functional group relative to 1 part by mass of the compound having the carboxy group and a polymerizable functional group is preferably 2.0 parts by mass, and the preferred upper limit is 10.0 parts by mass. When the content of the compound having the ring-opening skeleton of caprolactone and a polymerizable functional group relative to 1 part by mass of the compound having the carboxy group and a polymerizable functional group is within this range, the obtained photocurable resin composition has an effect of suppressing peeling of the wafer during dicing and is more excellent in chemical resistance. The more preferred lower limit of the content of the compound having the ring-opening skeleton of caprolactone and a polymerizable functional group relative to 1 part by mass of the compound having the carboxy group and a polymerizable functional group is 4.0 parts by mass, the more preferred upper limit is 9.0 parts by mass, and the even more preferred upper limit is 8.0 parts by mass.

[0022] In addition, when the curable resin contains a compound having the ring-opening skeleton of caprolactone and a polymerizable functional group, the total content ratio of the compound having the carboxyl group and the polymerizable functional group and the compound having the ring-opening skeleton of caprolactone and the polymerizable functional group in the entire curable resin is preferably 80% by mass or more. When the total content ratio of the compound having the carboxyl group and the polymerizable functional group and the compound having the ring-opening skeleton of caprolactone and the polymerizable functional group is 80% by mass or more, the obtained photocurable resin composition has better adhesion to the wafer. The more preferable lower limit of the total content ratio of the compound having the carboxyl group and the polymerizable functional group and the compound having the ring-opening skeleton of caprolactone and the polymerizable functional group is 90% by mass. Furthermore, the total content of the compound having a carboxy group and a polymerizable functional group, and the compound having a ring-opened skeleton of caprolactone and a polymerizable functional group in the entire curable resin may be 100 mass%, that is, the curable resin may contain only the compound having a carboxy group and a polymerizable functional group, and the compound having a ring-opened skeleton of caprolactone and a polymerizable functional group.

[0023] The curable resin may include, as the other curable resin, a curable resin other than the compound having the ring-opened caprolactone skeleton and a polymerizable functional group. Examples of such curable resins include (meth)acrylic compounds other than those included in the compound having a carboxy group and a polymerizable functional group and the compound having a ring-opened skeleton of caprolactone and a polymerizable functional group.

[0024] Examples of the other (meth)acrylic compounds include (meth)acrylic acid ester compounds, epoxy (meth)acrylates, urethane (meth)acrylates, etc. From the viewpoint of reactivity, the other (meth)acrylic compounds preferably have two or more (meth)acryloyl groups in one molecule. In this specification, the term "(meth)acrylate" means acrylate or methacrylate, and the term "epoxy (meth)acrylate" refers to a compound in which all epoxy groups in an epoxy compound have been reacted with (meth)acrylic acid.

[0025] Examples of the monofunctional (meth)acrylic acid ester compounds include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate, isononyl (meth)acrylate, isodecyl (meth)acrylate, lauryl (meth)acrylate, isomyristyl (meth)acrylate, stearyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, and bicyclopentenyl (meth)acrylate. Acrylate, benzyl (meth)acrylate, 2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, 2-butoxyethyl (meth)acrylate, 2-phenoxyethyl (meth)acrylate, methoxyethylene glycol (meth)acrylate, methoxypolyethylene glycol (meth)acrylate, phenoxydiethylene glycol (meth)acrylate, phenoxypolyethylene glycol (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, ethyl carbitol (meth)acrylate, 2,2,2-trifluoroethyl (meth)acrylate, 2,2,3,3-tetrafluoropropyl (meth)acrylate, 1H,1H,5H-octafluoropentyl (meth)acrylate, imide (meth)acrylate, dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, and the like.

[0026] Examples of the bifunctional (meth)acrylic acid ester compounds include 1,3-butanediol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, 1,10-decanediol di(meth)acrylate, ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, 2-n-butyl-2-ethyl-1,3-propanediol di(meth)acrylate, dipropylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, and polypropylene glycol. di(meth)acrylate, neopentyl glycol di(meth)acrylate, ethylene oxide-added bisphenol A di(meth)acrylate, propylene oxide-added bisphenol A di(meth)acrylate, ethylene oxide-added bisphenol F di(meth)acrylate, dimethylol dicyclopentadienyl di(meth)acrylate, ethylene oxide-modified isocyanuric acid di(meth)acrylate, 2-hydroxy-3-(meth)acryloyloxypropyl (meth)acrylate, carbonate diol di(meth)acrylate, polyether diol di(meth)acrylate, polyester diol di(meth)acrylate, polybutadiene diol di(meth)acrylate, tricyclodecane dimethanol di(meth)acrylate, and the like.

[0027] Furthermore, examples of the (meth)acrylic acid ester compounds having three or more functional groups include trimethylolpropane tri(meth)acrylate, ethylene oxide-added trimethylolpropane tri(meth)acrylate, propylene oxide-added trimethylolpropane tri(meth)acrylate, ethylene oxide-added isocyanuric acid tri(meth)acrylate, glycerin tri(meth)acrylate, propylene oxide-added glycerin tri(meth)acrylate, pentaerythritol tri(meth)acrylate, tris(meth)acryloyloxyethyl phosphate, ditrimethylolpropane tetra(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, and dipentaerythritol hexa(meth)acrylate.

[0028] The epoxy (meth)acrylate may, for example, be one obtained by reacting an epoxy compound with (meth)acrylic acid in the presence of a basic catalyst according to a conventional method.

[0029] Examples of epoxy compounds that serve as raw materials for synthesizing the above-mentioned epoxy (meth)acrylates include bisphenol A type epoxy compounds, bisphenol F type epoxy compounds, bisphenol E type epoxy compounds, bisphenol S type epoxy compounds, 2,2'-diallyl bisphenol A type epoxy compounds, hydrogenated bisphenol type epoxy compounds, propylene oxide-added bisphenol A type epoxy compounds, resorcinol type epoxy compounds, biphenyl type epoxy compounds, sulfide type epoxy compounds, diphenyl ether type epoxy compounds, dicyclopentadiene type epoxy compounds, naphthalene type epoxy compounds, phenol novolac type epoxy compounds, ortho-cresol novolac type epoxy compounds, dicyclopentadiene novolac type epoxy compounds, biphenyl novolac type epoxy compounds, naphthalene phenol novolac type epoxy compounds, glycidyl amine type epoxy compounds, alkyl polyol type epoxy compounds, rubber-modified type epoxy compounds, and glycidyl ester compounds.

[0030] The urethane (meth)acrylate can be obtained, for example, by reacting an isocyanate compound with a (meth)acrylic acid derivative having a hydroxyl group in the presence of a catalytic amount of a tin compound.

[0031] Examples of the isocyanate compound that is a raw material for the urethane (meth)acrylate include isophorone diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, diphenylmethane-4,4'-diisocyanate (MDI), hydrogenated MDI, polymeric MDI, 1,5-naphthalene diisocyanate, norbornane diisocyanate, tolidine diisocyanate, xylylene diisocyanate (XDI), hydrogenated XDI, lysine diisocyanate, triphenylmethane triisocyanate, tris(isocyanatephenyl)thiophosphate, tetramethylxylylene diisocyanate, and 1,6,11-undecane triisocyanate.

[0032] As the isocyanate compound serving as a raw material for the urethane (meth)acrylate, a chain-extended isocyanate compound obtained by reacting a polyol with an excess of an isocyanate compound can also be used. Examples of the polyol include ethylene glycol, propylene glycol, glycerin, sorbitol, trimethylolpropane, carbonate diol, polyether diol, and polyester diol.

[0033] Examples of the (meth)acrylic acid derivative having a hydroxyl group include hydroxyalkyl mono(meth)acrylates, mono(meth)acrylates of dihydric alcohols, mono(meth)acrylates or di(meth)acrylates of trihydric alcohols, and epoxy (meth)acrylates. Examples of the hydroxyalkyl mono(meth)acrylate include 2-hydroxyethyl(meth)acrylate, 2-hydroxypropyl(meth)acrylate, 2-hydroxybutyl(meth)acrylate, and 4-hydroxybutyl(meth)acrylate. Examples of the dihydric alcohol include ethylene glycol, propylene glycol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, and polyethylene glycol. Examples of the trihydric alcohol include trimethylolethane, trimethylolpropane, and glycerin. The epoxy (meth)acrylate may, for example, be bisphenol A type epoxy (meth)acrylate.

[0034] The content of the curable resin in the photocurable resin composition of the present invention (in the components excluding the solvent when the composition contains a solvent) is preferably 5.0% by mass at the lower limit and 20.0% by mass at the upper limit. By setting the content of the curable resin in this range, the resulting photocurable resin composition has better adhesion to the wafer. The content of the curable resin is more preferably 8.0% by mass at the lower limit and 15.0% by mass at the upper limit.

[0035] The photocurable resin composition of the present invention preferably further contains a photopolymerization initiator. Examples of the photopolymerization initiator include benzophenone compounds, acetophenone compounds, acylphosphine oxide compounds, titanocene compounds, oxime ester compounds, benzoin ether compounds, and thioxanthone compounds. Specific examples of the photopolymerization initiator include 1-hydroxycyclohexyl phenyl ketone, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-1-butanone, 2-(dimethylamino)-2-((4-methylphenyl)methyl)-1-(4-(4-morpholinyl)phenyl)-1-butanone, 2,2-dimethoxy-1,2-diphenylethan-1-one, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, 2-methyl-1-(4-methylphenyl ... 1-(4-(2-hydroxyethoxy)phenyl)-2-methyl-1-propan-1-one, 1-(4-(phenylthio)phenyl)-1,2-octanedione 2-(O-benzoyloxime), 2-(acetoxyimino)-1-(4-(4-(2-hydroxyethoxy)phenylthio)phenyl)propan-1-one, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, and the like. The photopolymerization initiators may be used alone or in combination of two or more kinds.

[0036] The content of the photopolymerization initiator is preferably 0.1 parts by mass at the lower limit and 10 parts by mass at the upper limit with respect to 100 parts by mass of the curable resin. By the content of the photopolymerization initiator being within this range, the obtained photocurable resin composition has better storage stability and photocurability. The more preferred lower limit of the content of the photopolymerization initiator is 1 part by mass, and the more preferred upper limit is 5 parts by mass.

[0037] The photocurable resin composition of the present invention may contain a heat curing agent. However, from the viewpoint of curing the photocurable resin composition of the present invention without carrying out a heating step, it is preferable that the composition does not contain the heat curing agent.

[0038] The photocurable resin composition of the present invention may further contain a thermoplastic resin from the viewpoint of improving adhesion to a wafer by stress relaxation.

[0039] Examples of the thermoplastic resin include polyvinyl butyral, polyurethane, and styrene-ethylene-butylene-styrene block copolymer. Among them, polyvinyl butyral is preferable. The thermoplastic resin may be used alone or in combination of two or more kinds.

[0040] The content of the thermoplastic resin is preferably 1.0 parts by mass at the lower limit and 10.0 parts by mass at the upper limit with respect to 100 parts by mass of the curable resin. By the content of the thermoplastic resin being within this range, the obtained photocurable resin composition has better adhesion to the wafer. The more preferred lower limit of the content of the thermoplastic resin is 3.0 parts by mass, and the more preferred upper limit is 5.0 parts by mass.

[0041] The photocurable resin composition of the present invention may contain a filler, but from the viewpoint of transparency, it is preferable that the composition does not contain the above-mentioned filler.

[0042] The photocurable resin composition of the present invention may contain a solvent. When the photocurable resin composition of the present invention contains a solvent, the solvent is removed after the composition is applied to a wafer and before the wafer is bonded to increase the viscosity, thereby preventing the composition from bleeding out when the wafer is bonded.

[0043] Examples of the solvent include aromatic solvents, alcohol solvents, amide solvents, lactone solvents, carbonate solvents, glyme solvents, and aprotic polar solvents. Examples of the aromatic solvent include benzene, toluene, and xylene. Examples of the alcohol-based solvent include methanol, ethanol, and isopropyl alcohol. Examples of the amide solvent include N,N'-dimethylformamide, N,N'-dimethylacetamide, and N-methyl-2-pyrrolidone. Examples of the lactone solvent include γ-butyrolactone, γ-valerolactone, and δ-valerolactone. Examples of the carbonate solvent include ethylene carbonate and propylene carbonate. Examples of the glyme-based solvent include monoglyme, diglyme, and triglyme. The aprotic polar solvent may, for example, be dimethyl sulfoxide.

[0044] The content of the solvent is preferably 10.0 parts by mass at the lower limit and 30.0 parts by mass at the upper limit with respect to 100 parts by mass of the curable resin. By the content of the solvent being within this range, the photocurable resin composition obtained has better coatability and workability. The more preferred lower limit of the content of the solvent is 15.0 parts by mass, and the more preferred upper limit is 20.0 parts by mass.

[0045] Furthermore, the photocurable resin composition of the present invention may contain various known additives, such as a leveling agent, a curing retarder, a reinforcing agent, a viscosity modifier, and an antioxidant, as necessary, within the scope of not impairing the object of the present invention.

[0046] The photocurable resin composition of the present invention has a wavelength of 300 nm or more and 400 nm or less and an illuminance of 100 mW / cm 2 More than 1000mW / cm 2 Irradiation time: 10 seconds or more, 60 seconds or less, cumulative light intensity: 1500 mJ / cm 2 More than 5000mJ / cm 2 The composition can be suitably cured by irradiation with the following light.

[0047] Examples of light sources used for irradiating light when curing the photocurable resin composition of the present invention include low pressure mercury lamps, medium pressure mercury lamps, high pressure mercury lamps, ultra-high pressure mercury lamps, excimer lasers, chemical lamps, black light lamps, microwave excited mercury lamps, metal halide lamps, sodium lamps, halogen lamps, xenon lamps, LED lamps, fluorescent lamps, sunlight, electron beam irradiation devices, etc. These light sources may be used alone or in combination of two or more.

[0048] Examples of means for irradiating the photocurable resin composition of the present invention with light include simultaneous irradiation with various light sources, sequential irradiation with a time lag, and a combination of simultaneous irradiation and sequential irradiation. Any irradiation means may be used.

[0049] When the photocurable resin composition of the present invention does not contain a solvent, the photocurable resin composition is exposed to a wavelength of 365 nm and an illuminance of 100 mW / cm 2 The preferred upper limit of the glass transition temperature of the cured product obtained by irradiating the photocurable resin composition of the present invention with light of a wavelength of 365 nm and an illuminance of 100 mW / cm for 30 seconds is 80° C., and when the photocurable resin composition of the present invention contains a solvent, the solvent is removed from the photocurable resin composition, and then the cured product is cured with light of a wavelength of 365 nm and an illuminance of 10 2 The preferred upper limit of the glass transition temperature of the cured product obtained by irradiating the photocurable resin composition with light for 30 seconds is 80° C. When the glass transition temperature of the cured product is 80° C. or lower, the photocurable resin composition can be photocured and then heated at a low temperature (80° C.) to further improve the adhesive strength to the wafer while controlling the gap between the wafers. The more preferred upper limit of the glass transition temperature of the cured product is 70° C. There is no particular preferred lower limit for the glass transition temperature of the cured product, but the substantial lower limit is 30°C. When the photocurable resin composition of the present invention contains a solvent, a method for removing the solvent from the photocurable resin composition may include, for example, applying the photocurable resin composition to a thickness of 100 μm on a release PET film (manufactured by Lintec Corporation, "PET5011") using a bar coater (manufactured by RD specialities, No. 37) and heating at 80° C. for 5 minutes. In addition, in this specification, the "glass transition temperature" refers to the temperature at which the maximum due to micro-Brownian motion appears among the maximum loss tangent (tan δ) obtained by dynamic viscoelasticity measurement. Specifically, the glass transition temperature is determined by performing dynamic viscoelasticity measurement using a dynamic viscoelasticity measuring device under the conditions of a test piece width of 5 mm, a thickness of 0.50 mm, a tensile mode, a grip width of 25 mm, a heating rate of 10°C / min, a temperature range of 0°C to 150°C, and a frequency of 1 Hz. Examples of the dynamic viscoelasticity measuring device include DVA-200 (manufactured by IT Keisoku Seigyo Co., Ltd.).

[0050] When the photocurable resin composition of the present invention does not contain a solvent, the photocurable resin composition is exposed to a wavelength of 365 nm and an illuminance of 100 mW / cm 2 The preferred lower limit of the storage modulus at 25°C of the cured product obtained by irradiating the photocurable resin composition of the present invention with light of a wavelength of 365 nm and an illuminance of 100 mW / cm for 30 seconds is 2.0 GPa. 2 The preferred lower limit of the storage modulus at 25°C of the cured product obtained by irradiating the cured product with light for 30 seconds is 2.0 GPa. When the storage modulus at 25°C of the cured product is 2.0 GPa or more, the cured product is more effective in suppressing peeling during dicing after bonding wafers (e.g., silicon wafer and glass wafer). The more preferred lower limit of the storage modulus at 25°C of the cured product is 2.5 GPa. Further, there is no particular preferred upper limit to the storage modulus of the cured product at 25° C., but the substantial upper limit is 5.0 GPa. Specifically, the storage modulus is determined by performing dynamic viscoelasticity measurement using a dynamic viscoelasticity measuring device under the conditions of a test piece width of 5 mm, a thickness of 0.50 mm, a tensile mode, a grip width of 25 mm, a heating rate of 10°C / min, a temperature range of 0°C to 150°C, and a frequency of 1 Hz.

[0051] The photocurable resin composition of the present invention preferably has a haze of 1% or less. Since the haze is 1% or less, the photocurable resin composition of the present invention can be suitably used for laminating wafers (e.g., silicon wafers and glass wafers) in the manufacture of semiconductor parts that require high transparency, and can be particularly suitably used in the manufacture of CMOS image sensors and the like. The more preferred upper limit of the haze is 0.5%. The above-mentioned haze means the ratio of diffuse transmitted light to the total transmitted light, and can be measured, for example, by using a spectrometer such as COH-7700 (manufactured by Nippon Denshoku Industries Co., Ltd.).

[0052] The photocurable resin composition of the present invention is suitably used for bonding wafers (for example, a silicon wafer and a glass wafer), and is particularly suitable for use in the wafer bonding step in the manufacture of CMOS image sensors. Effect of the Invention

[0053] According to the present invention, it is possible to provide a photocurable resin composition which, when cured, has excellent adhesion to a wafer, can suppress peeling of the wafer during dicing, and has excellent chemical resistance. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0054] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0055] (Synthesis Example 1) 105 parts by mass of 2-hydroxyethyl acrylate, 114 parts by mass of ε-caprolactone, and 0.2 parts by mass of hydroquinone as a polymerization inhibitor were added to a reaction flask, and the mixture was stirred at 90°C for 5 hours using a mantle heater, after which 148 parts by mass of phthalic anhydride was added and stirred for another 5 hours. Next, 170 parts by mass of bisphenol A diglycidyl ether was added to the resulting reaction product, and the mixture was stirred at 90°C for 5 hours to obtain a curable resin mixture. 1 H-NMR and 13 By C-NMR, the obtained curable resin mixture was found to be a compound represented by the above formula (1) (R 1 is hydrogen, R 2 is an ethylene group, R 3 It was confirmed that the copolymer contains a 1,2-phenylene group, X is a ring-open structure of ε-caprolactone, n is 1.01 (average value), and Ep is a structure derived from bisphenol A diglycidyl ether.

[0056] (Examples 1 to 3 and Comparative Examples 1 and 2) The photocurable resin compositions of Examples 1 to 3 and Comparative Examples 1 and 2 were prepared by stirring and mixing the materials using a stirring mixer according to the compounding ratios shown in Table 1. Awatori Rentaro ARE-310 (manufactured by Thinky Corporation) was used as the stirring mixer. Each of the obtained photocurable resin compositions was subjected to irradiation with a metal halide lamp at a wavelength of 365 nm and an illumination intensity of 100 mW / cm. 2 A cured product was obtained by irradiating the sample with light for 30 seconds. Dynamic viscoelasticity measurements were performed on the cured product using a dynamic viscoelasticity measuring device (manufactured by IT Measurement & Control Co., Ltd., "DVA-200") under the following conditions: test piece width 5 mm, thickness 0.50 mm, tensile mode, grip width 25 mm, heating rate 10°C / min, temperature range 0°C to 150°C, and frequency 1 Hz. The temperature at the maximum value of the loss tangent (tan δ) was determined as the glass transition temperature, and is shown in Table 1. The storage modulus at 25°C is also shown in Table 1.

[0057] <Evaluation> The photocurable resin compositions obtained in the Examples and Comparative Examples were evaluated as follows. The results are shown in Table 1.

[0058] (viscosity) The viscosity of each photocurable resin composition obtained was measured at 25° C. and 5 rpm (value 3 minutes after the start of rotation) using an E-type viscometer with a CP1-type cone plate. The E-type viscometer used was a VISCOMETER TV-22 (manufactured by Toki Sangyo Co., Ltd.).

[0059] (Adhesion to glass (wafer)) Each of the obtained photocurable resin compositions was dropped onto one of two glass substrates (glass substrate A), and then the other glass substrate (glass substrate B) was overlapped with glass substrate A in a cross shape so that the diameter of the photocurable resin composition sandwiched between glass substrates A and B was 3 mm. Next, a metal halide lamp was used to illuminate the glass substrate with a wavelength of 365 nm and an illuminance of 100 mW / cm. 2The photocurable resin composition was cured by irradiating the sample with light for 30 seconds to obtain a test piece. The obtained test piece was placed with glass substrate B facing downward, and both ends of glass substrate A were fixed from below. Both ends of glass substrate B were compressed from above with a precision universal testing machine at 25°C and a speed of 5 mm / min to measure the adhesive strength between glass substrate A and glass substrate B. An autograph AG-Xplus (manufactured by Shimadzu Corporation) was used as the precision universal testing machine. A test piece prepared in the same manner was heated at 80°C for 30 minutes, and the adhesive strength between glass substrate A and glass substrate B was measured in the same manner. The adhesive strength measured for the test piece after heating at 80°C for 30 minutes was 6.0 kgf / cm 2 If it is more than 6.0kgf / cm, it is "A". 2 If the adhesion was less than 10%, the adhesion to the glass (wafer) was rated as "B".

[0060] (Dicing ability) A frame having a gap of about 70 μm was provided on a glass substrate using Kapton tape, and each of the obtained photocurable resin compositions was dropped and filled into the frame. Next, another glass substrate was placed on the photocurable resin composition, and a metal halide lamp was used to illuminate the composition at a wavelength of 365 nm and an illuminance of 100 mW / cm. 2 The photocurable resin composition was cured by irradiating the glass substrate with light of 1000 nm for 30 seconds. The Kapton tape was then peeled off to obtain a test piece. The test piece was diced using a wire saw to check for peeling of the glass substrate. The dicing property was evaluated based on the following criteria: "A" indicates that no peeling of the glass substrate was observed, and "B" indicates that peeling of the glass substrate was observed.

[0061] (Chemical resistance) A frame having a gap of about 70 μm was provided on a glass substrate using Kapton tape, and each of the obtained photocurable resin compositions was dropped into the frame to fill it in. Next, a release PET film was placed on the photocurable resin composition, and a metal halide lamp was used to illuminate the composition at a wavelength of 365 nm and an illuminance of 100 mW / cm. 2The photocurable resin composition was cured by irradiating the photocurable resin composition with light for 30 seconds. The Kapton tape and the release PET film were then peeled off to obtain a test piece. The test piece obtained was immersed in a choline aqueous solution (concentration: 4% by mass) at 60°C for 30 minutes, and the erosion of the cured product of the photocurable resin composition by the choline aqueous solution and the presence or absence of peeling of the glass substrate were confirmed. The chemical resistance was evaluated based on the following criteria: "A" indicates that neither erosion nor peeling was observed, and "B" indicates that at least one of erosion and peeling was observed.

[0062] [Table 1] [Industrial Applicability]

[0063] According to the present invention, it is possible to provide a photocurable resin composition which, when cured, has excellent adhesion to a wafer, can suppress peeling of the wafer during dicing, and has excellent chemical resistance.

Claims

1. A photocurable resin composition for use by coating on a wafer, comprising: Contains a curable resin, the curable resin includes a compound having a carboxy group and a polymerizable functional group, The content of the compound having a carboxy group and a polymerizable functional group in 100 parts by mass of the photocurable resin composition is 9 parts by mass or more and 40 parts by mass or less. A photocurable resin composition comprising:

2. A photocurable resin composition for use by coating on a wafer, comprising: Contains a curable resin, the curable resin includes a compound having a carboxy group and a polymerizable functional group, The number of carboxy groups in one molecule of the compound having a carboxy group and a polymerizable functional group is A, and the content of the compound having a carboxy group and a polymerizable functional group in the curable resin is W. Ａ (mass %), the molecular weight of the compound having a carboxy group and a polymerizable functional group is M Ａ The molecular weight of the components other than the compound having a carboxy group and a polymerizable functional group contained in the curable resin is M Ｂ The content ratio of components other than the compound having a carboxy group and a polymerizable functional group in the curable resin is W Ｂ (mass%), the carboxy value Y in the entire curable resin calculated by the following formula (I) is 9.0 × 10 －５ Above 4.0 x 10 －４ is less than or equal to A photocurable resin composition comprising: Y=(A×W Ａ ) / (M Ａ ×W Ａ +M Ｂ ×W Ｂ ) (I)

3. 3. The photocurable resin composition according to claim 1, wherein the curable resin further comprises a compound having a ring-opened caprolactone skeleton and a polymerizable functional group.

4. 4. The photocurable resin composition according to claim 3, wherein the content of the compound having a ring-opened caprolactone skeleton and a polymerizable functional group is 2.0 parts by mass or more and 10.0 parts by mass or less relative to 1 part by mass of the compound having a carboxy group and a polymerizable functional group.

5. 3. The photocurable resin composition according to claim 1, which is used in a wafer lamination step in the manufacture of a CMOS image sensor.

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