Photocurable resin composition

Abstract

The purpose of the present invention is to provide a photocurable resin composition which exhibits excellent adhesion of a cured product to a wafer and which is capable of suppressing wafer peeling during dicing. The present invention relates to a photocurable resin composition which is used by being coated on a wafer, the photocurable resin composition containing a curable resin, and the photocurable resin composition being capable of being used by being coated on the wafer when the photocurable resin composition does not contain a solvent. The storage modulus of a cured product obtained by irradiating the photocurable resin composition with light having a wavelength of 365 nm and an illuminance of 100 mW / cm2 for 30 seconds at 25 DEG C is 2.0 GPa or more, and when the photocurable resin composition contains a solvent, after the solvent is removed from the photocurable resin composition, the storage modulus of the cured product at 25 DEG C is 2.0 GPa or more. And a cured product obtained by irradiating with light having a wavelength of 365 nm and an illuminance of 100 mW / cm2 for 30 seconds has a storage modulus of 2.0 GPa or more at 25 DEG C.

Description

Technical Field

[0001] This invention relates to photocurable resin compositions. Background Technology

[0002] In recent years, a method known as wafer-level CSP has been developed as a method for mounting semiconductor components. With wafer-level CSP, since internal wiring is not performed using bonding wires, it is possible to achieve thinner semiconductor components. Furthermore, since the dicing process is performed together after the packaging process of multiple semiconductor chips, the productivity is excellent. In the packaging process performed before the dicing process, a curable resin composition is used to bond the silicon wafer to the glass wafer (for example, Patent Document 1).

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: International Publication No. 2018 / 030140 Summary of the Invention

[0006] The problem that the invention aims to solve

[0007] When using conventional curable resin compositions, even if sufficient adhesive force is exhibited when bonding wafers (e.g., silicon wafers and glass wafers), wafer peeling sometimes occurs during subsequent dicing processes. Therefore, there is a need for curable resin compositions that not only provide sufficient adhesive force when bonding wafers but also suppress wafer peeling during dicing.

[0008] The purpose of this invention is to provide a photocurable resin composition that exhibits excellent adhesion of the cured material to wafers and can suppress wafer peeling during dicing.

[0009] Methods for solving problems

[0010] This disclosure 1 relates to a photocurable resin composition for coating onto a wafer, the photocurable resin composition containing a curable resin, wherein the photocurable resin composition is irradiated with a wavelength of 365 nm and an illuminance of 100 mW / cm² without containing a solvent. 2 The cured product obtained by irradiating with light for 30 seconds has a storage modulus of 2.0 GPa or higher at 25°C. In the case where the photocurable resin composition contains a solvent, after removing the solvent from the photocurable resin composition, irradiation at a wavelength of 365 nm and an illuminance of 100 mW / cm² is performed. 2 The solidified material obtained by 30 seconds of light exposure has a storage modulus of over 2.0 GPa at 25°C.

[0011] This disclosure 2 relates to a photocurable resin composition of this disclosure 1, wherein the photocurable resin comprises a compound having a carboxyl group and a polymerizable functional group.

[0012] This disclosure 3 relates to a photocurable resin composition of disclosure 1 or 2, wherein the photocurable resin comprises a compound having an open-ring backbone of caprolactone and polymerizable functional groups.

[0013] This disclosure 4 relates to a photocurable resin composition of this disclosure 1, wherein the photocurable resin comprises a compound having a carboxyl group and a polymerizable functional group, and a compound having a caprolactone ring-opening skeleton and a polymerizable functional group. The content of the compound having a carboxyl group and a polymerizable functional group is 0.20 parts by mass or more and 2.40 parts by mass or less, relative to 1 part by mass of the compound having a carboxyl group and a polymerizable functional group, and the total content of the compound having a carboxyl group and a polymerizable functional group and the compound having a caprolactone ring-opening skeleton and a polymerizable functional group in the total photocurable resin is 80% by mass or more.

[0014] This disclosure 5 relates to photocurable resin compositions of disclosures 1, 2, 3 or 4, used in the wafer bonding process of CMOS image sensor manufacturing.

[0015] The present invention will now be described in detail.

[0016] The inventors investigated a photocurable resin composition used for coating wafers and determined that the storage modulus of the photocurable resin composition (or, in the case of a solvent-containing photocurable resin composition, the solvent-free photocurable resin composition) at 25°C after photocuring reached a specific value or higher. The results showed that a cured product with excellent adhesion to the wafer and the ability to suppress wafer peeling during dicing could be obtained, thus completing the present invention.

[0017] The photocurable resin composition of the present invention is coated onto a wafer for use.

[0018] By applying the photocurable resin composition of the present invention to a wafer, it is possible to bond wafers (e.g., silicon wafers and glass wafers) using the photocurable resin composition of the present invention.

[0019] Examples of wafers coated with the photocurable resin composition of the present invention include silicon wafers and glass wafers.

[0020] Furthermore, spin coating is a suitable method for coating the photocurable resin composition of the present invention onto a wafer.

[0021] When the photocurable resin composition of the present invention is coated onto a wafer by the above spin coating method, it is preferable to perform the coating 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.

[0022] When the photocurable resin composition of the present invention does not contain a solvent, the photocurable resin composition is irradiated with a wavelength of 365 nm and an illuminance of 100 mW / cm. 2 The cured product obtained by irradiation for 30 seconds has a storage modulus of 2.0 GPa or higher at 25°C. In the case where the photocurable resin composition of the present invention contains a solvent, after removing the solvent from the photocurable resin composition, irradiation at a wavelength of 365 nm and an illuminance of 100 mW / cm² is performed. 2 The cured material obtained by applying light for 30 seconds has a storage modulus of 2.0 GPa or higher at 25°C. By ensuring that the storage modulus of the cured material is 2.0 GPa or higher at 25°C, the effect of suppressing peeling during dicing after bonding wafers (e.g., silicon wafers and glass wafers) becomes excellent. The preferred lower limit of the storage modulus of the cured material at 25°C is 2.5 GPa.

[0023] In addition, there is no particular upper limit to the preferred storage modulus of the above-mentioned solidified material at 25°C, but the actual upper limit is 5.0 GPa.

[0024] It should be noted that, in the case where 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 onto a release PET film (manufactured by LINTEC, "PET5011") with a thickness of 100 μm using a bar coater (manufactured by RD Specialities, No. 37) and heating it at 80°C for 5 minutes.

[0025] In addition, specifically, the above-mentioned storage modulus was determined by 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 clamping 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.

[0026] The photocurable resin composition of the present invention contains a curable resin.

[0027] The aforementioned curable resin preferably contains compounds having carboxyl groups and polymerizable functional groups. By containing the aforementioned compounds having carboxyl groups and polymerizable functional groups, the photocurable resin composition of the present invention exhibits superior adhesion to wafers.

[0028] Examples of polymerizable functional groups in compounds having carboxyl and polymerizable functional groups include (meth)acryloyl, (meth)acrylamido, vinyl, thiol, and epoxy groups. Among these, (meth)acryloyl is preferred.

[0029] It should be noted that in this specification, "(meth)acryloyl" refers to acryloyl or methacryloyl, and "(meth)acrylic acid" refers to acrylic acid or methacrylic acid.

[0030] Specifically, examples of compounds having carboxyl and polymerizable functional groups include 2-(meth)acryloyloxyethyl phthalate and 2-(meth)acryloyloxyethyl hexahydrophthalate.

[0031] The preferred lower limit for the content of the compound having carboxyl groups and polymeric functional groups in 100 parts by weight of the aforementioned curable resin is 20 parts by weight, and the preferred upper limit is 60 parts by weight. By setting the content of the compound having carboxyl groups and polymeric functional groups in 100 parts by weight of the aforementioned curable resin within this range, the resulting photocurable resin composition exhibits superior adhesion to the wafer. A more preferred lower limit for the content of the compound having carboxyl groups and polymeric functional groups in 100 parts by weight of the aforementioned curable resin is 30 parts by weight, and a more preferred upper limit is 50 parts by weight.

[0032] The aforementioned curable resin preferably comprises a compound having a caprolactone ring-opening backbone and polymerizable functional groups. By comprising the aforementioned compound having a caprolactone ring-opening backbone and polymerizable functional groups, the photocurable resin composition of the present invention exhibits superior adhesion to wafers through stress relaxation.

[0033] It should be noted that compounds having a carboxyl group, a caprolactone open-ring skeleton, and a polymerizable functional group are treated as compounds having a caprolactone open-ring skeleton and a polymerizable functional group as described above.

[0034] Examples of polymerizable functional groups in compounds having an open-ring skeleton of caprolactone and polymerizable functional groups include (meth)acryloyl, (meth)acrylamido, vinyl, thiol, and epoxy groups. Among these, (meth)acryloyl is preferred.

[0035] Specifically, examples of compounds having an open-ring skeleton of caprolactone and polymerizable functional groups include compounds represented by the following formula (1).

[0036] [Chemical Formula 1]

[0037]

[0038] In equation (1), R1 R represents a hydrogen atom or a methyl group. 2 R represents the group shown in formula (2-1), (2-2), or (2-3) below. 3 The structure is derived from a dicarboxylic acid or its anhydride that can be substituted, X represents the open ring structure of caprolactone, n is 1 or more and 5 or less, and Ep represents the structure derived from an epoxy compound with more than 2 functions.

[0039] [Chemical Formula 2]

[0040]

[0041] In equations (2-1), (2-2), and (2-3), * and ** represent bonding positions. In equation (2-2), a is an integer greater than or equal to 1 and less than 8. In equation (2-3), b is an integer greater than or equal to 1 and less than 8, c is an integer greater than or equal to 1 and less than 3, and d is an integer greater than or equal to 1 and less than 8. In equations (2-1) and (2-3), * represents the bonding position with the (meth)acryloyloxy group in equation (1).

[0042] The preferred lower limit for the content of the compound having a caprolactone-containing ring-opening backbone and polymerizable functional groups in 100 parts by weight of the aforementioned curable resin is 10 parts by weight, and the preferred upper limit is 50 parts by weight. By setting the content of the compound having a caprolactone-containing ring-opening backbone and polymerizable functional groups in 100 parts by weight of the aforementioned curable resin within this range, the resulting photocurable resin composition exhibits superior adhesion to the wafer. The more preferred lower limit for the content of the compound having a caprolactone-containing ring-opening backbone and polymerizable functional groups in 100 parts by weight of the aforementioned curable resin is 20 parts by weight, and the more preferred upper limit is 40 parts by weight.

[0043] The curable resin described above preferably includes both the compound having a carboxyl group and a polymerizable functional group, and the compound having a caprolactone ring-opening skeleton and a polymerizable functional group.

[0044] When the aforementioned curable resin comprises both the compound having carboxyl groups and polymerizable functional groups, and the compound having a caprolactone ring-opening backbone and polymerizable functional groups, the preferred lower limit of the content of the compound having caprolactone ring-opening backbone and polymerizable functional groups is 0.20 parts by mass, and the preferred upper limit is 2.40 parts by mass, relative to 1 part by mass of the compound having carboxyl groups and polymerizable functional groups. By setting the content of the compound having caprolactone ring-opening backbone and polymerizable functional groups within this range relative to 1 part by mass of the compound having carboxyl groups and polymerizable functional groups, the resulting photocurable resin composition exhibits superior adhesion to wafers. The more preferred lower limit of the content of the compound having caprolactone ring-opening backbone and polymerizable functional groups is 0.25 parts by mass, and the more preferred upper limit is 0.80 parts by mass, relative to 1 part by mass of the compound having carboxyl groups and polymerizable functional groups.

[0045] Furthermore, when the curable resin comprises both the compound having carboxyl groups and polymeric functional groups, and the compound having a caprolactone ring-opening backbone and polymeric functional groups, the total content of the compound having carboxyl groups and polymeric functional groups and the compound having a caprolactone ring-opening backbone and polymeric functional groups in the curable resin is preferably 80% by mass or more. By making the total content of the compound having carboxyl groups and polymeric functional groups and the compound having a caprolactone ring-opening backbone and polymeric functional groups 80% by mass or more, the resulting photocurable resin composition exhibits superior adhesion to wafers. A more preferable lower limit for the total content of the compound having carboxyl groups and polymeric functional groups and the compound having a caprolactone ring-opening backbone and polymeric functional groups is 90% by mass.

[0046] Furthermore, the total content of the compounds having carboxyl groups and polymeric functional groups and the compounds having caprolactone open-ring skeletons and polymeric functional groups in the curing resin as a whole can be 100% by mass, that is, the curing resin can contain only the compounds having carboxyl groups and polymeric functional groups and the compounds having caprolactone open-ring skeletons and polymeric functional groups.

[0047] The aforementioned curable resin may include other curable resins besides the compounds having carboxyl groups and polymerizable functional groups and the compounds having caprolactone ring-opening skeletons and polymerizable functional groups.

[0048] Other curable resins mentioned above include, for example, compounds other than those containing carboxyl groups and polymerizable functional groups, as well as compounds containing caprolactone ring-opening skeletons and polymerizable functional groups.

[0049] Other examples of (meth)acrylic compounds mentioned above include (meth)acrylate compounds, epoxy (meth)acrylates, and urethane (meth)acrylates. Furthermore, from a reactivity point of view, these other (meth)acrylic compounds preferably have two or more (meth)acryloyl groups in one molecule.

[0050] It should be noted that in this specification, "(meth)acrylate" refers to acrylate or methacrylate, and "epoxy (meth)acrylate" refers to a compound obtained by reacting all the epoxy groups in an epoxy compound with (meth)acrylic acid.

[0051] Examples of monofunctional compounds among the aforementioned (meth)acrylate compounds include: methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate, isononyl (meth)acrylate, isodecanyl (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 so on. Bicyclopentenyl acrylate, benzyl acrylate, 2-methoxyethyl acrylate, 2-ethoxyethyl acrylate, 2-butoxyethyl acrylate, 2-phenoxyethyl acrylate, methoxyethylene glycol (meth)acrylate, methoxy polyethylene glycol (meth)acrylate, phenoxydiethylene glycol (meth)acrylate, phenoxypolyethylene glycol (meth)acrylate, tetrahydrofurfuryl acrylate, ethyl carbitol (meth)acrylate, 2,2,2-trifluoroethyl acrylate, 2,2,3,3-tetrafluoropropyl acrylate, 1H,1H,5H-octafluoropentyl acrylate, imide (meth)acrylate, dimethylaminoethyl acrylate, diethylaminoethyl acrylate, etc.

[0052] Furthermore, examples of difunctional compounds among the aforementioned (meth)acrylate 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, and tripropylene glycol di(meth)acrylate. Polypropylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, ethylene oxide addition bisphenol A di(meth)acrylate, propylene oxide addition bisphenol A di(meth)acrylate, ethylene oxide addition bisphenol F di(meth)acrylate, dihydroxymethyldicyclopentadienyl di(meth)acrylate, ethylene oxide modified isocyanuric acid di(meth)acrylate, 2-hydroxy-3-(meth)acryloyloxypropyl (meth)acrylate, carbonate glycol di(meth)acrylate, polyether glycol di(meth)acrylate, polyester glycol di(meth)acrylate, polybutadiene glycol di(meth)acrylate, tricyclodecanediethanol di(meth)acrylate, etc.

[0053] In addition, examples of compounds with three or more functions among the aforementioned (meth)acrylate compounds include: trimethylolpropane tri(meth)acrylate, ethylene oxide addition trimethylolpropane tri(meth)acrylate, propylene oxide addition trimethylolpropane tri(meth)acrylate, ethylene oxide addition isocyanurate tri(meth)acrylate, glycerol tri(meth)acrylate, propylene oxide addition glycerol tri(meth)acrylate, pentaerythritol tri(meth)acrylate, tri(meth)acryloyloxyethyl phosphate, bis(trimethylolpropane tetra(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, etc.

[0054] Examples of the aforementioned epoxy (meth)acrylates include epoxy (meth)acrylates obtained by reacting an epoxy compound with (meth)acrylic acid in the presence of a basic catalyst using conventional methods.

[0055] Examples of epoxy compounds that can be used as raw materials for the synthesis of the aforementioned 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 addition bisphenol A type epoxy compounds, resorcinol type epoxy compounds, biphenyl type epoxy compounds, thioether type epoxy compounds, diphenyl ether type epoxy compounds, dicyclopentadiene type epoxy compounds, naphthyl type epoxy compounds, phenolic aldehyde type epoxy compounds, o-cresol aldehyde type epoxy compounds, dicyclopentadiene aldehyde type epoxy compounds, biphenyl aldehyde type epoxy compounds, naphthol aldehyde type epoxy compounds, glycidylamine type epoxy compounds, alkyl polyol type epoxy compounds, rubber-modified epoxy compounds, glycidyl ester compounds, etc.

[0056] The aforementioned urethane (meth)acrylates can be obtained, for example, by reacting a hydroxyl-containing (meth)acrylate derivative with an isocyanate compound in the presence of a catalytic amount of a tin-based compound.

[0057] Examples of isocyanate compounds that can serve as raw materials for the aforementioned urethane (meth)acrylates include: isophorone diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, diphenylmethane-4,4'-diisocyanate (MDI), hydrogenated MDI, polymerized MDI, 1,5-naphthalene diisocyanate, norbornene diisocyanate, dimethylbiphenyl diisocyanate, phenylmethylene diisocyanate (XDI), hydrogenated XDI, lysine diisocyanate, triphenylmethane triisocyanate, tri(isocyanate phenyl)thiophosphate, tetramethylphenylmethylene diisocyanate, and 1,6,11-undecane triisocyanate.

[0058] Alternatively, the isocyanate compound used as a raw material for the aforementioned urethane (meth)acrylate can be a chain-extended isocyanate compound obtained by reacting a polyol with an excess of the isocyanate compound.

[0059] Examples of such polyols include ethylene glycol, propylene glycol, glycerin, sorbitol, trimethylolpropane, carbonate glycol, polyether glycol, and polyester glycol.

[0060] Examples of the above-mentioned (meth)acrylic acid derivatives having hydroxyl groups include: hydroxyalkyl mono(meth)acrylates, mono(meth)acrylates of diols, mono(meth)acrylates or di(meth)acrylates of triols, epoxy (meth)acrylates, etc.

[0061] Examples of the above-mentioned hydroxyalkyl mono(meth)acrylates include: 2-hydroxyethyl(meth)acrylate, 2-hydroxypropyl(meth)acrylate, 2-hydroxybutyl(meth)acrylate, 4-hydroxybutyl(meth)acrylate, etc.

[0062] Examples of the aforementioned diols include ethylene glycol, propylene glycol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, and polyethylene glycol.

[0063] Examples of the aforementioned triols include trimethylolethane, trimethylolpropane, and glycerol.

[0064] Examples of the aforementioned epoxy (meth)acrylates include, for example, bisphenol A type epoxy (meth)acrylates.

[0065] The preferred lower limit of the content of the curable resin in the photocurable resin composition of the present invention (or, in the case of a solvent, components other than the solvent) is 5.0% by mass, and the preferred upper limit is 20.0% by mass. By setting the content of the curable resin within this range, the resulting photocurable resin composition exhibits superior adhesion to the wafer. A more preferred lower limit of the content of the curable resin is 8.0% by mass, and a more preferred upper limit is 15.0% by mass.

[0066] The photocurable resin composition of the present invention preferably further contains a photopolymerization initiator.

[0067] Examples of photopolymerization initiators include benzophenone compounds, acetophenone compounds, phosphine oxide compounds, titanoceramsite compounds, oxime ester compounds, benzoin ether compounds, and thioxanone compounds.

[0068] Specifically, examples of photopolymerization initiators include: 1-hydroxycyclohexylphenyl ketone, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-1-butanone, 2-(dimethylamino)-2-((4-methylphenyl)methyl)-1-(4-(4-morpholino)phenyl)-1-butanone, 2,2-dimethoxy-1,2-diphenylethane-1-one, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, 2-methyl- 1-(4-methylthiophenyl)-2-morpholinopropane-1-one, 1-(4-(2-hydroxyethoxy)-phenyl)-2-hydroxy-2-methyl-1-propane-1-one, 1-(4-(phenylthio)phenyl)-1,2-octanedione, 2-(O-benzoyl oxime), 2-(acetoxyimino)-1-(4-(4-(2-hydroxyethoxy)phenylthio)phenyl)propane-1-one, 2,4,6-trimethylbenzoyl diphenylphosphine oxide, etc.

[0069] The above-mentioned photopolymerization initiators can be used alone or in combination of two or more.

[0070] The preferred lower limit for the content of the photopolymerization initiator relative to 100 parts by weight of the aforementioned curable resin is 0.1 parts by weight, and the preferred upper limit is 10 parts by weight. By setting the content of the photopolymerization initiator within this range, the resulting photocurable resin composition exhibits superior storage stability and photocurability. A more preferred lower limit for the content of the photopolymerization initiator is 1 part by weight, and a more preferred upper limit is 5 parts by weight.

[0071] The photocurable resin composition of the present invention may contain a thermosetting agent, but from the viewpoint of curing the photocurable resin composition of the present invention without performing a heating process, it is preferable not to contain the aforementioned thermosetting agent.

[0072] From the viewpoint of adhesion to wafers based on stress relaxation, the photocurable resin composition of the present invention may further contain a thermoplastic resin.

[0073] Examples of the aforementioned thermoplastic resins include polyvinyl butyral, polyurethane, and styrene-ethylene-butene-styrene block copolymers. Polyvinyl butyral is preferred. These thermoplastic resins can be used alone or in combination of two or more.

[0074] The preferred lower limit for the content of the thermoplastic resin relative to 100 parts by weight of the curable resin is 1 part by weight, and the preferred upper limit is 10 parts by weight. By setting the content of the thermoplastic resin within this range, the resulting photocurable resin composition exhibits superior adhesion to the wafer. A more preferred lower limit for the content of the thermoplastic resin is 3 parts by weight, and a more preferred upper limit is 5 parts by weight.

[0075] The photocurable resin composition of the present invention may contain fillers, but from the viewpoint of transparency, it is preferable not to contain the aforementioned fillers.

[0076] The photocurable resin composition of the present invention may contain a solvent. When the photocurable resin composition of the present invention contains a solvent, by removing the solvent after coating the wafer and before bonding the wafer to thicken it, exudation during wafer bonding can be suppressed.

[0077] Examples of solvents mentioned above include aromatic solvents, alcohol solvents, amide solvents, lactone solvents, carbonate solvents, ethylene glycol ether solvents, and aprotic polar solvents.

[0078] Examples of aromatic solvents mentioned above include benzene, toluene, and xylene.

[0079] Examples of alcohol solvents mentioned above include methanol, ethanol, and isopropanol.

[0080] Examples of amide solvents mentioned above include N,N'-dimethylformamide, N,N'-dimethylacetamide, and N-methyl-2-pyrrolidone.

[0081] Examples of lactone solvents mentioned above include γ-butyrolactone, γ-valerolactone, and δ-valerolactone.

[0082] Examples of carbonate solvents include ethylene carbonate and propylene carbonate.

[0083] Examples of ethylene glycol ether solvents include monoethylene glycol methyl ether, diethylene glycol methyl ether, and triethylene glycol methyl ether.

[0084] Examples of aprotic polar solvents include dimethyl sulfoxide.

[0085] The preferred lower limit for the solvent content relative to 100 parts by weight of the curable resin is 10 parts by weight, and the preferred upper limit is 30 parts by weight. By setting the solvent content within this range, the coatability and workability of the resulting photocurable resin composition become more excellent. A more preferred lower limit for the solvent content is 15 parts by weight, and a more preferred upper limit is 20 parts by weight.

[0086] Furthermore, the photocurable resin composition of the present invention may contain various known additives such as leveling agents, curing delay agents, reinforcing agents, viscosity modifiers, and antioxidants as needed, without hindering the purpose of the present invention.

[0087] The viscosity of the photocurable resin composition of the present invention is adjusted according to the coating method. For example, when coating by spin coating, the preferred lower limit of the viscosity at 25°C is 0.10 Pa·s, the preferred upper limit is 3.0 Pa·s, the more preferred lower limit is 1.0 Pa·s, and the more preferred upper limit is 2.0 Pa·s.

[0088] It should be noted that the above viscosity can be measured using an E-type viscometer, employing a suitable cone plate, and selecting a rotation speed of 1 to 100 rpm from the optimal torque range for each viscosity region. Examples of such E-type viscometers include the VISCOMETER TV-22 (manufactured by Toki Sangyo Co., Ltd.).

[0089] The photocurable resin composition of the present invention can be cured by irradiation with a wavelength of 300 nm or higher and 400 nm or lower, and an illuminance of 100 mW / cm². 2 Above and 1000mW / cm 2 The following conditions must be met: irradiation time of 10 seconds or more but less than 60 seconds, and cumulative light intensity of 1500 mJ / cm². 2 Above 5000mJ / cm2 The following light is used for proper curing.

[0090] Examples of light sources used for irradiating the photocurable resin composition of the present invention during curing include: low-pressure mercury lamps, medium-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, excimer lasers, chemical lamps, black lights, microwave-excited mercury lamps, metal halide lamps, sodium lamps, halogen lamps, xenon lamps, LED lamps, fluorescent lamps, sunlight, and electron beam irradiation devices. These light sources can be used individually or in combination of two or more.

[0091] As a method of irradiating the photocurable resin composition of the present invention with light, examples include simultaneous irradiation with various light sources, successive irradiation with time differences, and a combination of simultaneous and successive irradiation. Any irradiation method can be used.

[0092] When the photocurable resin composition of the present invention does not contain a solvent, the photocurable resin composition is irradiated with a wavelength of 365 nm and an illuminance of 100 mW / cm. 2 The preferred upper limit for the glass transition temperature of the cured product obtained by irradiation for 30 seconds is 80°C. In the case where the photocurable resin composition of the present invention contains a solvent, after removing the solvent from the photocurable resin composition, irradiation is performed at a wavelength of 365 nm and an illuminance of 100 mW / cm². 2 The preferred upper limit for the glass transition temperature of the cured material obtained by photocuring for 30 seconds is 80°C. By setting the glass transition temperature of the cured material to 80°C or below, it is possible to further improve the adhesion to the wafers while controlling the gap between wafers by heating after photocuring the photocurable resin composition at a low temperature (80°C). A more preferred upper limit for the glass transition temperature of the cured material is 75°C.

[0093] Furthermore, there is no particular limitation on the preferred lower limit of the glass transition temperature of the aforementioned cured material; in practice, the lower limit is 30°C.

[0094] It should be noted that, in this specification, the "glass transition temperature" refers to the temperature at which the maximum value of the loss tangent (tanδ) obtained by dynamic viscoelasticity measurement occurs due to micro-Brownian motion. Specifically, the glass transition temperature is determined by performing dynamic viscoelasticity measurements using a dynamic viscoelasticity measuring device under the following conditions: test piece width 5 mm, thickness 0.50 mm, tensile mode, clamping width 25 mm, heating rate 10 °C / min, temperature range 0 °C to 150 °C, and frequency 1 Hz. Examples of such dynamic viscoelasticity measuring devices include the DVA-200 (manufactured by IT Measurement & Control Co., Ltd.).

[0095] The preferred upper limit for the haze of the cured product of the photocurable resin composition of the present invention is 1%. By keeping the haze below 1%, the photocurable resin composition of the present invention is more suitable for bonding wafers (e.g., silicon wafers and glass wafers) in the manufacture of semiconductor components requiring high transparency, and is particularly suitable for the manufacture of CMOS image sensors, etc. A more preferred upper limit for the haze is 0.5%.

[0096] The haze mentioned above refers to the ratio of diffused transmitted light to total transmitted light, which can be measured, for example, using a spectrometer such as the COH-7700 (manufactured by Nippon Denshoku Kogyo Co., Ltd.).

[0097] The photocurable resin composition of the present invention is suitable for bonding wafers (e.g., silicon wafers and glass wafers), and is particularly suitable for the wafer bonding process in the manufacture of CMOS image sensors.

[0098] Invention Effects

[0099] According to the present invention, a photocurable resin composition is provided that exhibits excellent adhesion of the cured material to the wafer and can suppress wafer peeling during dicing. Detailed Implementation

[0100] The present invention will be described in more detail below with reference to specific embodiments, but the present invention is not limited to these embodiments.

[0101] (Synthesis example 1)

[0102] 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. The mixture was stirred at 90°C for 5 hours using a jacketed heater. Then, 148 parts by mass of phthalic anhydride were added, and the mixture was stirred for another 5 hours. Next, 170 parts by mass of bisphenol A diglycidyl ether were added to the resulting reactants, and the mixture was stirred at 90°C for 5 hours, thereby obtaining a curable resin mixture. 1 H-NMR and 13 C-NMR confirmed that the obtained curable resin mixture contained the compound (R) shown in formula (1) above. 1 For hydrogen, R 2 It is ethylene, R 3 1,2-Phenylidene, X is the open-ring structure of ε-caprolactone, n is 1.01 (average), and Ep is the structure derived from bisphenol A diglycidyl ether.

[0103] (Synthesis example 2)

[0104] While introducing air, 3550 parts by weight of carboxylic acid-terminated butadiene-acrylonitrile copolymer (manufactured by UBE, "CTBN1300X8"), 400 parts by weight of 4-hydroxybutyl methacrylate glycidyl ether (manufactured by Nippon Chemical Co., Ltd.), 10 parts by weight of p-methoxyphenol as a polymerization inhibitor, and 10 parts by weight of triethylamine as a reaction catalyst were refluxed and stirred at 110°C for 5 hours to obtain methacrylic acid-modified butadiene-acrylonitrile copolymer.

[0105] (Examples 1-5 and Comparative Examples 1 and 2)

[0106] Following the mixing ratios described in Table 1, the materials were mixed using a mixer to prepare the light-curable resin compositions of Examples 1-5 and Comparative Examples 1 and 2. An Awatori Rentaro ARE-310 (manufactured by THINKY Corporation) was used as the mixer. It should be noted that "CN704" in Table 1 refers to a carboxyl-containing difunctional polyester acrylate oligomer.

[0107] Using a bar coater (RD Specialities, No. 37), the obtained photocurable resin compositions were applied to a release PET film (LINTEC, "PET5011") to a thickness of 100 μm. The film was then dried at 80°C for 5 minutes to remove the solvent. After solvent removal, each photocurable resin composition was irradiated with a metal halide lamp at a wavelength of 365 nm and an illuminance of 100 mW / cm². 2 The solidified material was obtained by applying light for 30 seconds. The solidified material was then subjected to dynamic viscoelasticity testing using a dynamic viscoelasticity measuring device (IT Measurement & Control Co., Ltd., "DVA-200") under the following conditions: test piece width 5 mm, thickness 0.50 mm, tensile mode, clamping width 25 mm, heating rate 10 °C / min, temperature range 0 °C–150 °C, and frequency 1 Hz. The storage modulus at 25 °C is shown in Table 1. Furthermore, the temperature at which the maximum value of the loss tangent (tanδ) was determined is taken as the glass transition temperature and is shown in Table 1.

[0108] <Evaluation>

[0109] The photocurable resin compositions obtained in the Examples and Comparative Examples were evaluated as follows. The results are shown in Table 1.

[0110] (Coating properties and low exudation)

[0111] For each obtained photocurable resin composition, the viscosity (value after 3 minutes from the start of rotation) was measured at 25°C and 5 rpm using a CP1 type cone plate and an E-type viscometer. A VISCOMETER TV-22 (manufactured by Toki Sangyo Co., Ltd.) was used as the E-type viscometer. Viscosities below 3.0 Pa·s were designated as "A", and those exceeding 3.0 Pa·s were designated as "B". Coating properties (based on spin coating) were evaluated. It should be noted that for the photocurable resin compositions obtained in Example 5, Comparative Examples 1 and 2, the viscosity measurement involved in the evaluation of coating properties (based on spin coating) was not performed.

[0112] In addition, using a rod coater (RD Specialities, No. 37), each of the obtained photocurable resin compositions was applied to a release PET film (LINTEC, "PET5011") to a thickness of 100 μm, and dried at 80°C for 5 minutes to remove the solvent. The viscosity of each photocurable resin composition after solvent removal was also measured. Viscosities of 30.0 Pa·s or higher were designated as "A", and those less than 30.0 Pa·s were designated as "B", evaluating low exudation.

[0113] (Adhesion to glass (wafer))

[0114] The obtained photocurable resin compositions were drop-added onto one of two glass substrates (glass substrate A). The other glass substrate (glass substrate B) was then 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, the mixture was irradiated with a metal halide lamp at a wavelength of 365 nm and an illuminance of 100 mW / cm². 2 The photocurable resin composition was cured by applying light for 30 seconds to obtain a test piece. The test piece was then positioned with glass substrate B facing down, and both ends of glass substrate A were fixed from below. Using a precision universal testing machine, the ends of glass substrate B were compressed from above at 25°C and a speed of 5 mm / min, thereby measuring the adhesive force between glass substrate A and glass substrate B. The aforementioned precision universal testing machine was an Autograph AG-Xplus (manufactured by Shimadzu Corporation).

[0115] In addition, the same test pieces were heated at 80°C for 30 minutes, and the adhesive force between glass substrate A and glass substrate B was measured in the same manner. The adhesive force measured on the test pieces after heating at 80°C for 30 minutes was 6.0 kgf / cm². 2 The above situation is denoted as "A", and will be less than 6.0 kgf / cm². 2The condition is denoted as "B", which evaluates the adhesion to the glass (wafer).

[0116] (Cutting ability)

[0117] Using Kapton tape, frames with gaps of approximately 70 μm were formed on a glass substrate, and the obtained photocurable resin compositions were drop-filled into these frames. Next, another glass substrate was superimposed on the photocurable resin composition, and the substrate was irradiated with a metal halide lamp at a wavelength of 365 nm and an illuminance of 100 mW / cm². 2 The photocurable resin composition was cured by applying light for 30 seconds. Then, the Kapton tape was peeled off to obtain a test piece. The resulting test piece was then cut using a wire saw to confirm whether the glass substrate had peeled off.

[0118] Cases where glass substrate peeling is not confirmed are marked as "A", and cases where glass substrate peeling is confirmed are marked as "B". The cutability is evaluated.

[0119] [Table 1]

[0120]

[0121] Industrial availability

[0122] According to the present invention, a photocurable resin composition is provided that exhibits excellent adhesion of the cured material to the wafer and can suppress wafer peeling during dicing.

Claims

1. A photocurable resin composition, characterized in that, It is coated onto the chip for use. The photocurable resin composition contains a curable resin. When the photocurable resin composition does not contain a solvent, the photocurable resin composition is irradiated with a wavelength of 365 nm and an illuminance of 100 mW / cm. 2 The solidified material obtained by irradiating light for 30 seconds has a storage modulus of over 2.0 GPa at 25°C. When the photocurable resin composition contains a solvent, after removing the solvent from the photocurable resin composition, irradiation is performed at a wavelength of 365 nm and an illuminance of 100 mW / cm². 2 The solidified material obtained by 30 seconds of light exposure has a storage modulus of over 2.0 GPa at 25°C.

2. The photocurable resin composition according to claim 1, wherein, The curable resin comprises compounds having carboxyl groups and polymerizable functional groups.

3. The photocurable resin composition according to claim 1 or 2, wherein, The curable resin comprises a compound having a caprolactone ring-opening backbone and polymerizable functional groups.

4. The photocurable resin composition according to claim 1, wherein, The curable resin comprises compounds having carboxyl groups and polymerizable functional groups, as well as compounds having a caprolactone ring-opening skeleton and polymerizable functional groups. Relative to 1 part by mass of the compound having carboxyl and polymerizable functional groups, the content of the compound having a caprolactone ring-opening skeleton and polymerizable functional groups is 0.20 parts by mass or more and 2.40 parts by mass or less. The total content of the compounds having carboxyl groups and polymeric functional groups, as well as the compounds having caprolactone ring-opening skeletons and polymeric functional groups in the curable resin, is 80% by mass or more.

5. The photocurable resin composition according to claim 1, 2, 3 or 4, used in the wafer bonding process of CMOS image sensor manufacturing.

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