Methods for producing thin wafers

Abstract

A method for producing thin wafers includes: separating a support from a wafer laminate by irradiating the wafer laminate with light from the support side of the wafer laminate, the wafer laminate including a support, an adhesive layer formed on the support, and a wafer including a circuit plane facing the adhesive layer laminated thereon; and removing a residual resin layer from the wafer after separation by peeling; wherein the adhesive layer from the support side sequentially includes only a light-shielding resin layer A and a resin layer B comprising a thermosetting silicone resin or a non-silicone thermoplastic resin.

Description

[0001] Cross-reference to related applications

[0002] This non-provisional application claims priority to Japanese Patent Application No. 2018-164373, filed September 3, 2018, pursuant to Section 119(a) of Title 35 of the United States Code, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This invention relates to a method for producing thin wafers. Background Technology

[0004] Three-dimensional semiconductor packaging has become essential for achieving higher density and capacity. Three-dimensional packaging technology is a semiconductor manufacturing technique in which each thinned semiconductor chip is connected and stacked on top of each other through silicon through-holes (TSVs). This technology requires thinning a substrate containing semiconductor circuitry by grinding the non-circuit-forming surface (also known as the "back side") and forming electrodes including TSVs on the back side. Conventionally, in the back-side grinding step of the silicon substrate, a back-side protective tape is provided on the surface opposite to the surface to be ground to prevent damage to the wafer during grinding. However, this tape includes an organic resin film as a support base material, which is advantageous in flexibility but disadvantageous in insufficient strength and heat resistance. Therefore, this tape is unsuitable for the TSV formation step or the wiring layer formation step on the back side.

[0005] In view of the above, a system has been proposed in which a semiconductor substrate is bonded to a support made of silicon, glass, etc., wherein an adhesive layer is inserted between them. Thus, the substrate can withstand steps such as grinding the back side or forming a TSV or back electrode. It is important here that the adhesive layer is used to bond the substrate to the support. The adhesive layer needs to be durable enough to tightly bond the substrate to the support and withstand subsequent steps, and also needs to allow for easy separation of the thin wafer from the support at the end. Because the adhesive layer is ultimately separated, it is also referred to herein as a temporary adhesive layer.

[0006] As for known temporary adhesive layers and their separation methods, a technique has been proposed in which bonding and separation are carried out in a hot-molten state using a hot-melt hydrocarbon compound as an adhesive (Patent Document 1). This technique is simple because it is controlled solely by heating; however, its applicability is limited because of insufficient thermal stability at temperatures above 200°C.

[0007] Another technique using siloxane adhesives as a temporary adhesive layer has been proposed (Patent Document 2). In this technique, an addition-curable silicone adhesive is used to bond the substrate to the support, and during separation, the substrate is immersed in chemicals that dissolve or decompose the silicone resin, thereby separating the substrate from the support. Therefore, separating the substrate takes a long time and is thus difficult to apply to actual production processes.

[0008] On the other hand, another technique has been proposed in which an adhesive comprising a light-absorbing material is irradiated with high-intensity light to decompose the adhesive layer, thereby separating the adhesive layer from the support (Patent Document 3). The advantage of this method is that it requires less time to process each substrate in the separation of the substrate from the support; however, metal contamination may occur because a metal compound is needed to convert the transmitted light into heat. Additionally, when the adhesive layer remaining on the substrate is removed with a solvent, the decomposed adhesive is insoluble in the solvent, and therefore the remaining adhesive may re-adhere to the substrate, causing contamination.

[0009] Citation List

[0010] Patent Document 1: JP-A 2003-177528

[0011] Patent Document 2: WO 2015 / 072418

[0012] Patent Document 3: JP-A 2013-534721 Summary of the Invention

[0013] The present invention was made in view of the above-mentioned problems, and the object of the present invention is to provide a method for producing thin wafers that can easily separate the wafer from the support, remove resin without contaminating the wafer, and increase the productivity of thin wafers.

[0014] As a result of careful research to achieve the stated objective, the inventors have discovered that the above objective can be achieved by forming a wafer assembly by bonding a support and a wafer with a predetermined adhesive layer, separating the support from the wafer assembly, and then removing the residual adhesive layer by peeling. Thus, the present invention is completed.

[0015] Therefore, the present invention provides the following method for producing thin wafers.

[0016] 1. A method for producing a thin wafer, comprising: separating a support from a wafer laminate by irradiating the wafer laminate with light from a support side of the wafer laminate; and removing a residual resin layer from the wafer after separation by peeling; wherein the wafer laminate includes a support, an adhesive layer formed on the support, and a wafer including a circuit plane facing the adhesive layer stacked thereon; and the adhesive layer from the support side sequentially includes only a light-shielding resin layer A and a resin layer B comprising a thermosetting silicone resin or a non-silicone thermoplastic resin.

[0017] 2. The method for producing thin wafers according to claim 1, wherein the laminate is exposed to a temperature of 30 to 60°C during the separation of resin layer B from the wafer by peeling.

[0018] 3. The method for producing thin wafers according to 1 or 2, wherein the light-shielding resin layer A has a transmittance of less than 20% at a wavelength of 355 nm and a maximum absorption wavelength of 300 to 500 nm.

[0019] 4. The method for producing a thin wafer according to any one of 1 to 3, wherein the resin layer A comprises a cured resin composition A containing resin A, said resin A comprising repeating units represented by the following formula (1):

[0020]

[0021] Where R 1 To R 3 R independently represents a hydrogen atom, a hydroxyl group, or a monovalent organic group of 1 to 20 carbon atoms. 1 To R 3 At least one of them is a hydroxyl group, and R 4 A monovalent organic group representing a hydrogen atom or 1 to 30 carbon atoms that may have substituents.

[0022] 5. The method for producing thin wafers according to claim 4, wherein the resin composition A further comprises a crosslinking agent.

[0023] 6. The method for producing thin wafers according to 4 or 5, wherein the resin composition A further comprises an acid-generating agent.

[0024] 7. The method for producing thin wafers according to any one of 4 to 6, wherein the resin composition A further comprises an organic solvent.

[0025] 8. The method for producing thin wafers according to any one of 1 to 7, wherein the resin layer A has a thickness of 0.1 to 50 μm.

[0026] 9. The method for producing a thin wafer according to any one of 1 to 8, wherein the resin layer B includes a resin containing a siloxane skeleton and an epoxy group, and the resin containing a siloxane skeleton and an epoxy group includes a repeating unit represented by the following formula (2) and an optional repeating unit represented by the following formula (3):

[0027]

[0028] where R 31 to R 34 each independently represents a monovalent hydrocarbon group having 1 to 8 carbon atoms, m represents an integer of 1 to 100, A and B are numbers satisfying 0 < A ≤ 1, 0 ≤ B < 1, and A + B = 1, and X 1 and X 2 each represents a divalent organic group represented by the following formula (4):

[0029]

[0030] wherein, Y 1 represents a single bond, a methylene group, a propane-2,2-diyl group, a 1,1,1,3,3,3-hexafluoropropane-2,2-diyl group, or a fluorene-9,9-diyl group, R 41 and R 42 each independently represents an alkoxy group or an alkyl group having 1 to 4 carbon atoms, and p and q independently represent 0, 1, or 2.

[0031] 10. The method for producing a thin wafer according to any one of 1 to 8, wherein the resin layer B includes a non-organosilicon thermoplastic resin, and the non-organosilicon thermoplastic resin is at least one selected from the following: polyolefin-based thermoplastic elastomer, polybutadiene-based thermoplastic elastomer, polystyrene-based thermoplastic elastomer, polystyrene-butadiene-based thermoplastic elastomer, polystyrene-olefin-based thermoplastic elastomer, and hydrogenated products of these elastomers.

[0032] [[ID=�2]] Beneficial effects of the present invention

[0033] According to the present invention, the wafer can be easily separated from the support, the resin can be removed without contaminating the wafer, and the productivity of the thin wafer can be increased. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 is a schematic view showing a wafer laminate. DETAILED DESCRIPTION

[0035] The method for producing thin wafers according to the present invention includes: separating a support from a wafer laminate by irradiating the wafer laminate with light from the support side of the wafer laminate; and removing a residual resin layer from the wafer by peeling; said wafer laminate includes a support, an adhesive layer formed on the support, and a wafer including a circuit plane facing the adhesive layer laminated thereon.

[0036] Describe the structure of the wafer layer assembly in detail. For example, Figure 1 As shown, the support 1 and the wafer 3 are bonded together using an adhesive layer 2. The adhesive layer 2 comprises two layers: a resin layer 2a (resin layer A) formed in contact with the support 1 and a resin layer 2b (resin layer B) formed in contact with the resin layer 2a. In this invention, after the support is separated from the wafer laminate, the resin layer 2b is removed from the laminate by peeling.

[0037] support body

[0038] The support can be a transparent substrate, a silicon wafer, a ceramic substrate, etc., and a transparent substrate is preferred in terms of transmittance of laser light to be propagated in the separated support. The transparent substrate is typically a glass substrate or a quartz substrate, having a thickness preferably from 300 to 1,000 μm, more preferably from 500 to 800 μm.

[0039] Chips

[0040] The wafer is typically a semiconductor wafer. Examples of semiconductor wafers include silicon wafers, germanium wafers, gallium-arsenic wafers, gallium-phosphorus wafers, gallium-arsenic-aluminum wafers, etc. The thickness of the wafer is not limited to a specific thickness, but is generally preferred to be 600 to 800 μm, more preferably 625 to 775 μm.

[0041] Adhesive layer

[0042] The adhesive layer comprises only a light-shielding resin layer A and a resin layer B comprising a thermosetting silicone resin or a non-silicone thermoplastic resin. In the wafer assembly, resin layer A and resin layer B are formed sequentially from the support side.

[0043] Resin layer A

[0044] Resin layer A is a light-shielding resin layer (light-shielding layer) with a transmittance of preferably 20% or less, more preferably 18% or less, and even more preferably 15% or less at a wavelength of 355 nm. Resin layer A preferably has a maximum absorption wavelength of 300 to 500 nm, and more preferably 300 to 400 nm. Furthermore, resin layer A preferably has a transmittance of 20% or less at a wavelength of 300 to 500 nm.

[0045] From the viewpoints of heat resistance, adhesion, chemical resistance, etc., resin A included in resin layer A preferably contains a resin having fused rings in its main chain. Resin A preferably includes repeating units represented by the following formula (1). As a repeating unit represented by formula (1), it may include only one type, or it may include two or more types.

[0046]

[0047] In equation (1), R 1 To R 3 Independently representing a hydrogen atom, a hydroxyl group, or a monovalent organic group having 1 to 20 carbon atoms, preferably 1 to 10 carbon atoms, provided that R 1 To R 3 At least one of them is a hydroxyl group.

[0048] Examples of monovalent organic groups include: straight-chain, branched, or cyclic alkyl groups having 1 to 20 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, neopentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl, n-dodecyl, n-pentadecanyl, n-eicosyl, cyclopentyl, cyclohexyl, cyclopentylmethyl, cyclohexylmethyl, cyclopentylethyl, cyclohexylethyl, cyclopentylbutyl, cyclohexylbutyl, and adamantyl; straight-chain, branched, or cyclic alkoxy groups having 1 to 5 carbon atoms, such as methoxy; epoxy-containing groups, such as glycidyloxy; and aryl groups such as phenyl and naphthyl. 1 To R 3 Preferably, hydrogen atoms, hydroxyl groups, methyl groups, etc.

[0049] In equation (1), R 4 A monovalent organic group consisting of 1 to 30 carbon atoms, preferably 1 to 10 carbon atoms, and may include substituents, of hydrogen atoms. (By R) 4 Examples of monovalent organic groups include straight-chain, branched, or cyclic alkyl groups, aryl groups such as phenyl, naphthyl, and anthracene, and monovalent polycyclic saturated hydrocarbon groups such as norbornyl. These hydrogen atoms can be substituted by alkyl, aryl, aldehyde, halogen, nitro, nitrile, hydroxyl, etc.

[0050] Resin A can typically be obtained by using an acid or base as a catalyst, and subjecting naphthol or its derivatives to a polycondensation reaction with an aldehyde compound at room temperature or, if necessary, under cooling or heating conditions, with or without a solvent.

[0051] Examples of naphthol or its derivatives include 1-naphthol, 2-naphthol, 2-methyl-1-naphthol, 4-methoxy-1-naphthol, 7-methoxy-2-naphthol, 1,2-dihydroxynaphthol, 1,3-dihydroxynaphthol, 2,3-dihydroxynaphthol, 1,4-dihydroxynaphthol, 1,5-dihydroxynaphthol, 1,6-dihydroxynaphthol, 2,6-dihydroxynaphthol, 1,7-dihydroxynaphthol, 2,7-dihydroxynaphthol, 1,8- Dihydroxynaphthalene, 5-amino-1-naphthol, 2-methoxycarbonyl-1-naphthol, 1-(4-hydroxyphenyl)naphthalene, 6-(4-hydroxyphenyl)-2-naphthol, 6-(cyclohexyl)-2-naphthol, 1,1'-bi-2-naphthol, 6,6'-bi-2-naphthol, 9,9-bis(6-hydroxy-2-naphthyl)fluorene, 6-hydroxy-2-vinylnaphthalene, 1-hydroxymethylnaphthalene, and 2-hydroxymethylnaphthalene. Any of the above-mentioned naphthols or their derivatives may be used alone or in combination of two or more.

[0052] An example of an aldehyde compound is shown below.

[0053] R 4 -CHO

[0054] In the formula, R 4 Same as described above.

[0055] Examples of aldehyde compounds include formaldehyde, paraformaldehyde, paraformaldehyde, acetaldehyde, propionaldehyde, adamantane formaldehyde, benzaldehyde, phenylacetaldehyde, α-phenylpropionaldehyde, β-phenylpropionaldehyde, o-chlorobenzaldehyde, m-chlorobenzaldehyde, p-chlorobenzaldehyde, o-nitrobenzaldehyde, m-nitrobenzaldehyde, p-nitrobenzaldehyde, o-methylbenzaldehyde, m-methylbenzaldehyde, p-methylbenzaldehyde, p-ethylbenzaldehyde, p-n-butylbenzaldehyde, 1-naphthaldehyde, 2-naphthaldehyde, anthracene formaldehyde, pyrene formaldehyde, furfural, methyl acetal, o-phthalaldehyde, m-phthalaldehyde, terephthalaldehyde, naphthalene dicarboxaldehyde, anthracene dicarboxaldehyde, and pyrene dicarboxaldehyde. Any one of the above-mentioned aldehyde compounds may be used alone or in combination of two or more.

[0056] Examples of solvents used in polycondensation reactions include: alcohols such as methanol, ethanol, isopropanol, butanol, ethylene glycol, propylene glycol, diethylene glycol, glycerol, methyl cellosolve, ethyl cellosolve, butyl cellosolve, and propylene glycol monomethyl ether; ethers such as diethyl ether, dibutyl ether, diethylene glycol diethyl ether, diethylene glycol dimethyl ether, tetrahydrofuran (THF), and 1,4-dioxane; chlorinated solvents such as dichloromethane, chloroform, dichloromethane, and trichloroethylene; hydrocarbons such as hexane, heptane, benzene, toluene, xylene, and cumene; nitriles such as acetonitrile; ketones such as acetone, ethyl methyl ketone, and isobutyl methyl ketone; esters such as ethyl acetate, n-butyl acetate, and propylene glycol methyl ether acetate; lactones such as γ-butyrolactone; and aprotic polar solvents such as dimethyl sulfoxide, N,N-dimethylformamide, and hexamethylphosphoric triamine. Any of the above solvents may be used alone or in combination of two or more. Based on the total amount of naphthol or its derivatives and aldehyde compounds per 100 parts by weight, any of these solvents may preferably be used in an amount of 0 to 2,000 parts by weight, more preferably 10 to 2,000 parts by weight.

[0057] Examples of acid catalysts used in polycondensation reactions include: inorganic acids such as hydrochloric acid, hydrobromic acid, sulfuric acid, nitric acid, phosphoric acid, and heteropoly acids; organic acids such as oxalic acid, trifluoroacetic acid, methanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, and trifluoromethanesulfonic acid; and Lewis acids such as aluminum trichloride, aluminum ethoxylate, aluminum isopropoxylate, boron trifluoride, boron trichloride, boron tribromide, tin tetrachloride, tin tetrabromide, dibutyltin dichloride, dibutyldimethoxytin, dibutyltin oxide, titanium tetrachloride, titanium tetrabromide, methoxytitanium (IV), ethoxytitanium (IV), isopropoxytitanium (IV), and titanium oxide (IV).

[0058] Examples of base catalysts used in polycondensation reactions include: inorganic bases such as sodium hydroxide, potassium hydroxide, barium hydroxide, sodium carbonate, sodium bicarbonate, potassium carbonate, lithium hydride, sodium hydride, potassium hydride, and calcium hydride; alkyl metals such as methyllithium, n-butyllithium, methylmagnesium chloride, and ethylmagnesium bromide; alkoxides such as sodium methoxide, sodium ethoxide, and potassium tert-butoxide; and organic bases such as triethylamine, diisopropylethylamine, N,N-dimethylaniline, pyridine, and 4-dimethylaminopyridine.

[0059] The catalyst is preferably used in the amount of 0.001 to 100 parts by weight, more preferably 0.005 to 50 parts by weight, per 100 parts by weight of the total amount of naphthol or its derivatives and aldehyde compounds. The reaction temperature is preferably in the range of -50°C to the boiling point of the solvent, more preferably room temperature to 100°C.

[0060] Examples of polycondensation reaction methods include methods for co-preparing naphthol or its derivatives, aldehyde compounds, and catalysts, as well as methods for dropwise adding naphthol or its derivatives and aldehyde compounds in the presence of a catalyst.

[0061] Regarding the ratio of naphthol or its derivatives to aldehyde compounds, the aldehyde compounds are preferably used in a molar ratio of 0.01 to 5, more preferably 0.05 to 2, even more preferably 0.05 to 1, and most preferably 0.1 to 0.9, based on the total amount of naphthol or its derivatives.

[0062] To remove unreacted raw materials, catalysts, etc., remaining in the system after the polycondensation reaction, the temperature of the reaction vessel can be increased to 130 to 230°C and volatile substances can be removed at approximately 1 to 50 mmHg. Alternatively, the polymer can be fractionated by adding a suitable solvent or water, or the polymer can be dissolved in a good solvent and then redeprecipitated in a poor solvent. These methods can be selected based on the properties of the obtained reaction products.

[0063] The weight-average molecular weight (Mw) of resin A is preferably from 500 to 500,000, more preferably from 1,000 to 100,000. The polymer dispersion is preferably in the range of 1.2 to 20; removing monomeric components, oligomer components, or low molecular weight components with a Mw of less than 500 can suppress volatile components during baking and prevent contamination around the baking cup or surface defects due to dripping of evaporating components. In this invention, Mw is a measurement relative to polystyrene obtained by gel permeation chromatography (GPC) using THF as a solvent.

[0064] Resin layer A is preferably formed from a cured resin composition A containing resin A. Resin composition A preferably includes a crosslinking agent that crosslinks resin A through a thermal reaction. The crosslinking agent is preferably, for example, an epoxy compound having two or more functional groups in its molecule, or an epoxy resin, or an amino resin such as hydroxymethyl melamine, and preferably an additional catalyst is added to accelerate the crosslinking reaction between the crosslinking agent and the polymer.

[0065] Epoxy compounds and epoxy resins can be, for example, difunctional, trifunctional, tetrafunctional or more functional groups, such as EOCN-1020 (see the following formula), EOCN-102S, XD-1000, NC-2000-L, EPPN-201, GAN, NC6000 (Nippon Kayaku Co., Ltd.), or substances represented by the following formula.

[0066]

[0067] When using an epoxy compound or epoxy resin as a crosslinking agent, the mixing amount is preferably 0.1 to 50 parts by weight, more preferably 0.1 to 30 parts by weight, and even more preferably 1 to 30 parts by weight per 100 parts by weight of the polymer comprising repeating units represented by formula (1). Any crosslinking agent can be used alone or in combination of two or more. If the mixing amount is within the above range, sufficient crosslinking density is achieved and the resulting cured product functions properly.

[0068] When using epoxy resin as a crosslinking agent, it is preferable to add a curing accelerator as a catalyst. By using an epoxy resin curing accelerator, the curing reaction can be promoted appropriately and uniformly.

[0069] Examples of epoxy resin curing accelerators include imidazole compounds such as 2-methylimidazolium, 2-ethylimidazolium, 2-ethyl-4-methylimidazolium, ethyl isocyanates of these compounds, 2-phenylimidazolium, 2-phenyl-4-methylimidazolium, 2-phenyl-4-methyl-5-hydroxymethylimidazolium, and 2-phenyl-4,5-dihydroxymethylimidazolium; DBU compounds such as 1,8-diazabicyclo[5.4.0]undecene-7 (DBU), 1,5-di... Azabicyclo[4.3.0]nonene-5 (DBN), organic acid salts of DBU, phenolic resin salts of DBU, tetraphenylborates of DBU derivatives; triorganophosphines, such as triphenylphosphine, tributylphosphine, tris(p-methylphenyl)phosphine, tris(p-methoxyphenyl)phosphine, tris(p-ethoxyphenyl)phosphine, triphenylphosphine-triphenylborate, tetraphenylphosphine-tetraphenylborate; and quaternary phosphonium salts; tertiary amines, such as triethylammonium-triphenylborate and its tetraphenylborate. Any of these epoxy resin curing accelerators can be used alone, or in combination of two or more.

[0070] Based on 100 parts by weight of resin A, it contains preferably 0.1 to 10 parts by weight, more preferably 0.2 to 5 parts by weight of epoxy resin curing accelerator.

[0071] As an amino resin used in this invention, such as hydroxymethyl melamine, one or more components selected from the group consisting of phenolic compounds comprising an average of two or more hydroxymethyl or alkoxyhydroxymethyl groups in one molecule and amino condensates modified with formalin or formalin-alcohol can be used.

[0072] The amino resin has a Mw preferably from 150 to 10,000, more preferably from 200 to 3,000. If the Mw is within the above range, sufficient hardness is obtained and the cured composition has high heat resistance.

[0073] Examples of formalin- or formalin-alcohol-modified amino condensates include formalin- or formalin-alcohol-modified melamine condensates and formalin- or formalin-alcohol-modified urea condensates.

[0074] Formalin- or formalin-alcohol-modified melamine condensates can be prepared by modifying melamine monomers with formalin to form hydroxymethylates according to known methods, or by further modifying the product with alcohols to form alkoxylates, to produce modified melamine represented by the following formula. Examples of alcohols include lower alcohols, such as alcohols with 1 to 4 carbon atoms.

[0075]

[0076] In the formula, R 11 To R 16 Independently representing hydroxymethyl, including straight-chain, branched, or cyclic alkoxymethyl groups with 1 to 4 carbon atoms, or hydrogen atoms, and R 11 To R 16 At least one of them is hydroxymethyl or alkoxymethyl.

[0077] Examples of modified melamine include trimethoxymethyl melamine, dimethoxymethyl melamine, trimethylolamine, hexamethylolamine, and hexamethoxymethylolamine. Subsequently, the modified melamine or polymers derived from the modified melamine (e.g., oligomers such as dimers or trimers) are subjected to addition condensation polymerization with formaldehyde according to general methods until the desired molecular weight is achieved; thus, formalin- or formalin-alcohol-modified melamine condensates can be obtained. It should be noted that one or more of the modified melamine and the corresponding melamine condensate can be used as crosslinking agents.

[0078] Urea condensates modified with formalin or formalin-alcohol can be prepared by modifying a urea condensate with a desired molecular weight into a hydroxymethylated product with formalin according to known methods, or by further modifying the product into an alkoxylated product with an alcohol.

[0079] Specific examples of modified urea condensates include methoxymethylated urea condensates, ethoxymethylated urea condensates, and propoxymethylated urea condensates. One or more of these modified urea condensates may be used.

[0080] Among these, phenolic compounds that, on average, include at least two or more hydroxymethyl or alkoxyhydroxymethyl groups in one molecule are, for example, (2-hydroxy-5-methyl)-1,3-benzyldiethanol and 2,2',6,6'-tetramethoxymethylbisphenol A.

[0081] Any of these amino condensates and phenolic compounds can be used alone or in combination of two or more.

[0082] Based on 100 parts by weight of resin A, it contains preferably 0.1 to 50 parts by weight, more preferably 1 to 30 parts by weight of a crosslinking agent. Within this range, composition A is sufficiently cured and the resulting cured product functions properly.

[0083] If an amino resin such as hydroxymethyl melamine is used as a crosslinking agent, it is preferable to add a thermogenic acid-producing agent as a catalyst. This thermogenic acid-producing agent is not limited to a specific type; for example, an ammonium salt represented by the following formula is given.

[0084]

[0085] In the formula, R 21 To R 24 Independently representing a hydrogen atom, a straight-chain, branched, or cyclic alkyl or oxoalkyl group with 1 to 12 carbon atoms, a straight-chain, branched, or cyclic alkenyl or oxoalkenyl group with 2 to 12 carbon atoms, an aryl group with 6 to 20 carbon atoms, or an aralkyl or aryloxoalkyl group with 7 to 12 carbon atoms. The hydrogen atoms in these groups may be wholly or partially substituted with alkoxy groups. (Selected from R) 21 To R 24 The two nitrogen atoms that can bond to them can form a ring. This ring can be an alicyclic ring with 3 to 10 carbon atoms containing the nitrogen atom in the formula, or a heteroaromatic ring with 5 to 10 carbon atoms containing the nitrogen atom in the formula. X - It represents at least one fluorinated sulfonic acid anion, perfluoroalkylimide acid anion, or perfluoroalkylmethide acid anion at the α-position.

[0086] X - Specific examples include: perfluoroalkane sulfonate anions, such as trifluoromethanesulfonate anion and nonafluorobutanesulfonate anion; sulfonate anions having at least one α-fluorine substitution; imide anions, such as bis(trifluoromethanesulfonyl)imide anion, bis(perfluoroethylsulfonyl)imide anion and bis(perfluorobutylsulfonyl)imide anion; and methanide anions, such as tri(trifluoromethanesulfonyl)methaneide anion and tri(perfluoroethylsulfonyl)methaneide anion.

[0087] Based on 100 parts by weight of resin A, it contains preferably 0.1 to 15 parts by weight, more preferably 0.2 to 10 parts by weight of a thermogenic acid-producing agent. Within this range, composition A is fully cured and exhibits high storage stability.

[0088] Resin composition A may include a solvent. Examples of solvents include: ketones, such as cyclohexanone, cyclopentanone, and methyl-2-n-pentyl ketone; alcohols, such as 3-methoxybutanol, 3-methyl-3-methoxybutanol, 1-methoxy-2-propanol, and 1-ethoxy-2-propanol; ethers, such as propylene glycol monomethyl ether, ethylene glycol monomethyl ether, propylene glycol monoethyl ether, ethylene glycol monoethyl ether, propylene glycol dimethyl ether, and diethylene glycol dimethyl ether; and propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, ethyl lactate, ethyl pyruvate, butyl acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, tert-butyl acetate, tert-butyl propionate, propylene glycol monotert-butyl ether acetate, and γ-butyrolactone, as well as other esters. Any one of these solvents may be used alone or in combination of two or more. Based on 100 parts by weight of resin A, it contains preferably 100 to 5,000 parts by weight, more preferably 150 to 2,500 parts by weight of solvent.

[0089] Resin composition A can be used as a solvent-free film composition.

[0090] If desired, resin composition A may contain, for example, surfactants or antioxidants for enhancing heat resistance.

[0091] Surfactants are not limited to specific types, and examples include: polyoxyethylene alkyl ethers, such as polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene cetyl ether, and polyoxyethylene oleyl ether; polyoxyethylene alkyl aryl ethers, such as polyoxyethylene octylphenyl ether and polyoxyethylene nonylphenyl ether; polyoxyethylene polyoxypropylene block copolymers; sorbitan fatty acid esters, such as sorbitan monolaurate, sorbitan monopalmitate, and sorbitan monostearate; polyoxyethylene sorbitan fatty acid esters, such as polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan trioleate, and polyoxyethylene sorbitan tristearate, and other nonionic surfactants; EFTOP (registered trademarks) EF301, EF303, and EF352 (Tochem Products). Co., Ltd., Megaface (registered trademark) F171, F172 and F173 (DIC Corporation), Fluorad (registered trademark) FC430 and FC431 (3M), AsahiGuard AG710, Surflon (registered trademark) S-381, S-382, SC101, SC102, SC103, SC104, SC105 and SC106, Surfynol (registered trademark) E1004, KH-10, KH-20, KH-30 and KH-40 (AGC Inc.) and other fluorinated surfactants; and organosiloxane polymers KP341, X-70-092, X-70-093 and X-70-1102 (Shin-Etsu Chemical). (Co., Ltd.) and acrylic acid or methacrylic acid Polyflow No. 75 and No. 95 (Kyoeisha Chemical Co., Ltd.). Any of these can be used alone or in combination of two or more.

[0092] The antioxidant is preferably selected from at least one of hindered phenolic compounds, hindered amine compounds, organophosphorus compounds, and organosulfur compounds.

[0093] Hindered phenolic compounds are not limited to specific types; for example, the following compounds are preferred: 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene (product name: IRGANOX 1330); 2,6-di-tert-butyl-4-methylphenol (product name: Sumilizer BHT); 2,5-di-tert-butyl-hydroquinone (product name: Nocrac NS-7); 2,6-di-tert-butyl-4-ethylphenol (product name: Nocrac M-17); 2,5-di-tert-pentylhydroquinone (product name: Nocrac DAH); 2,2'-methylenebis(4-methyl-6-tert-butylphenol) (product name: Nocrac NS-6); diethyl 3,5-di-tert-butyl-4-hydroxybenzylphosphonate (product name: IRGANOX). 1222); 4,4'-Thiobis(3-methyl-6-tert-butylphenol) (Product name: Nocrac300); 2,2'-Methylenebis(4-ethyl-6-tert-butylphenol) (Product name: Nocrac NS-5); 4,4'-Butylidenebis(3-methyl-6-tert-butylphenol) (Product name: ADEKA STAB AO-40); 2-tert-butyl-6-(3-tert-butyl-2-hydroxy-5-methylbenzyl)-4-methylphenyl acrylate (Product name: Sumilizer GM); 2-[1-(2-hydroxy-3,5-di-tert-pentylphenyl)ethyl]-4,6-di-tert-pentylphenyl acrylate (Product name: Sumilizer) GS); 2,2'-Methylenebis[4-methyl-6-(α-methyl-cyclohexyl)phenol]; 4,4'-Methylenebis(2,6-di-tert-butylphenol (product name: SEENOX 226M); 4,6-bis(octylthiomethyl)-o-cresol (product name: IRGANOX 1520L); 2,2'-Ethylenebis(4,6-di-tert-butylphenol); Octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (product name: IRGANOX 1076); 1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane (product name: ADEKA STAB AO-30); Tetra[methylene-(3,5-di-tert-butyl-4-hydroxyhydrocinnamate)]methane (product name: ADEKA STAB) AO-60); Triethylene glycol bis[3-(3-tert-butyl-5-methyl-4-hydroxyphenyl)propionate] (product name: IRGANOX 245); 2,4-bis(n-octylthio)-6-(4-hydroxy-3,5-di-tert-butylaniline)-1,3,5-triazine (product name: IRGANOX 565); N,N'-hexamethylenebis(3,5-di-tert-butyl-4-hydroxy-hydrogenated cinnamamide) (product name: IRGANOX1098);1,6-Hexanediol-bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (Product name: IRGANOX 259); 2,2-Thio-diethylidene bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (Product name: IRGANOX 1035); 3,9-bis[2-[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy]1,1-dimethylethyl]-2,4,8,10-tetraoxazolo[5.5]undecane (Product name: Sumilizer GA-80); tris-(3,5-di-tert-butyl-4-hydroxybenzyl)isocyanurate (Product name: IRGANOX 3114); bis(3,5-di-tert-butyl-4-hydroxybenzylphosphonate ethyl)calcium / polyethylene wax mixture (50:50) (Product name: IRGANOX) 1425WL); isooctyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (product name: IRGANOX 1135); 4,4'-thiobis(6-tert-butyl-3-methylphenol) (product name: Sumilizer WX-R); and 6-[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propoxy]-2,4,8,10-tetra-tert-butyldibenzo[d,f][1,3,2]dioxophosphazene (product name: Sumilizer GP).

[0094] Hindered amine compounds are not limited to specific types; for example, the following compounds are preferred: p,p'-dioctyldiphenylamine (product name: IRGANOX 5057); phenyl-α-naphthylamine (product name: Nocrac PA); poly(2,2,4-trimethyl-1,2-dihydroquinoline) (product name: Nocrac 224,224-S); 6-ethoxy-2,2,4-trimethyl-1,2-dihydroquinoline (product name: Nocrac AW); N,N'-diphenyl-p-phenylene diamine (product name: Nocrac DP); N,N'-di-β-naphthyl-p-phenylene diamine (product name: Nocrac White); N-phenyl-N'-isopropyl-p-phenylene diamine (product name: Nocrac 810NA); N,N'-diallyl-p-phenylene diamine (product name: Nonflex) TP); 4,4'-(α,α-dimethylbenzyl)diphenylamine (product name: Nocrac CD); p,p-toluenesulfonylaminodiphenylamine (product name: Nocrac TD); N-phenyl-N'-(3-methacryloyloxy-2-hydroxypropyl)-p-phenylenediamine (product name: Nocrac G1); N-(1-methylheptyl)-N'-phenyl-p-phenylenediamine (product name: Ozonon 35); N,N'-di-sec-butyl-p-phenylenediamine (product name: Sumilizer BPA); N-phenyl-N'-1,3-dimethylbutyl-p-phenylenediamine (product name: Antigene 6C); alkylated diphenylamine (product name: Sumilizer 9A); dimethyl-1-(2-hydroxyethyl)-4-hydroxy-2,2,6,6-tetramethylpiperidine condensate (product name: Tinuvin) 622LD); Poly[[6-(1,1,3,3-tetramethylbutyl)amino-1,3,5-triazine-2,4-diyl][(2,2,6,6-tetramethyl-4-piperidinyl)imino]hexamethylene[(2,2,6,6-tetramethyl-4-piperidinyl)imino]] (Product name: CHIMASSORB944); N,N'-bis(3-aminopropyl)ethylenediamine-2,4-bis[N-butyl-N-(1,2,2,6,6-pentamethyl-4-piperidinyl)amino]-6-chloro-1,3,5-triazine condensate (Product name: CHIMASSORB119FL); bis(1-octyloxy-2,2,6,6-tetramethyl-4-piperidinyl) sebacate (Product name: TINUVIN) 123); Bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate (product name: TINUVIN 770); 2-(3,5-di-tert-butyl-4-hydroxybenzyl)-2-n-butylmalonic acid bis(1,2,2,6,6-pentamethyl-4-piperidinyl) (product name: TINUVIN 144);Bis(1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate (product name: TINUVIN 765); tetra(1,2,2,6,6-pentamethyl-4-piperidinyl)1,2,3,4-butanetetracarboxylate (product name: LA-57); tetra(2,2,6,6-tetramethyl-4-piperidinyl)1,2,3,4-butanetetracarboxylate (product name: LA-52); esterification product of a mixture of 1,2,3,4-butanetetracarboxylic acid with 1,2,2,6,6-pentamethyl-4-piperidinol and 1-tridecaneol (product name: LA-62); esterification product of a mixture of 1,2,3,4-butanetetracarboxylic acid with 2,2,6,6-tetramethyl-4-piperidinol and 1-tridecaneol (product name: LA-67); 1,2,3,4-butanetetracarboxylic acid with 2,2,6,6-tetramethyl-4-piperidinol and 1-tridecaneol Esterification products of a mixture of alkyltetracarboxylic acid with 1,2,2,6,6-pentamethyl-4-piperidinol and 3,9-bis(2-hydroxy-1,1-dimethylethyl)-2,4,8,10-tetraoxaspiro[5.5]undecane (product name: LA-63P); esterification products of a mixture of 1,2,3,4-butanetetracarboxylic acid with 2,2,6,6-tetramethyl-4-piperidinol and 3,9-bis(2-hydroxy-1,1-dimethylethyl)-2,4,8,10-tetraoxaspiro[5.5]undecane (product name: LA-68LD); (2,2,6,6-tetramethylene-4-piperidinyl)-2-propylene carboxylate (product name: ADEKA) STAB LA-82; and (1,2,2,6,6-pentamethyl-4-piperidinyl)-2-propylene carbamate (product name: ADEKASTAB LA-87).

[0095] Organophosphorus compounds are not limited to specific types; for example, the following compounds are preferred: bis(2,4-di-tert-butylphenyl)[1,1-biphenyl]-4,4'-dimethylbisphosphite; 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (product name: SANKO-HCA); triethyl phosphite (product name: JP302); tri-n-butyl phosphite (product name: JP304); triphenyl phosphite (product name: ADEKA STAB TPP); diphenyl monooctyl phosphite (product name: ADEKA STAB C); tri(p-cresol) phosphite (product name: Chelex-PC); diphenyl monodecyl phosphite (product name: ADEKA STAB) 135A); Diphenyl mono(tridecyl) phosphite (product name: JPM313); Tri(2-ethylhexyl) phosphite (product name: JP308); Phenyl didecyl phosphite (product name: ADEKA STAB 517); Tridecyl phosphite (product name: ADEKA STAB 3010); Tetraphenyl dipropylene glycol diphosphite (product name: JPP100); Bis(2,4-di-tert-butylphenyl) pentaerythritol diphosphite (product name: ADEKA STAB PEP-24G); Tri(tridecyl) phosphite (product name: JP333E); Bis(nonylphenyl) pentaerythritol diphosphite (product name: ADEKA STAB PEP-4C); Bis(2,6-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphite (product name: ADEKA STAB) PEP-36); Bis[2,4-Di(1-phenylisopropyl)phenyl]pentaerythritol diphosphite (product name: ADEKA STAB PEP-45); Trilauryl trithiophosphite (product name: JPS312); Tris(2,4-di-tert-butylphenyl) phosphite (product name: IRGAFOS 168); Tris(nonylphenyl) phosphite (product name: ADEKA STAB 1178); Distearate pentaerythritol diphosphite (product name: ADEKA STAB PEP-8); Tris(mono, dinonylphenyl) phosphite (product name: ADEKA STAB) 329K); Triolein phosphite (product name: Chelex-OL); Tristearin phosphite (product name: JP318E); 4,4'-Butylidene bis(3-methyl-6-tert-butylphenyl di(tetrazyl)) phosphite (product name: JPH1200); Tetra(C 12 -C 15Mixed alkyl)-4,4'-isopropylidene diphenyl diphosphite (product name: ADEKA STAB1500); tetra(tridecyl)-4,4'-butylidene bis(3-methyl-6-tert-butylphenol) diphosphite (product name: ADEKA STAB 260); hexa(tridecyl)-1,1,3-tris(2-methyl-5-tert-butyl-4-hydroxyphenyl)butane-triphosphite (product name: ADEKA STAB) 522A); Hydrogenated bisphenol A phosphite polymer (HBP); Tetra(2,4-di-tert-butylphenoxy)4,4'-biphenyl-diphosphine (product name: P-EPQ); Tetra(2,4-di-tert-butyl-5-methylphenoxy)4,4'-biphenyl-diphosphine (product name: GSY-101P); 2-[[2,4,8,10-tetra(1,1-dimethylethyl)dibenzo[d,f][1,3,2]dioxophosphazene-6-yl]oxy]-N,N-bis[2-[[2,4,8,10-tetra(1,1-dimethylethyl)dibenzo[d,f][1,3,2]dioxophosphazene-6-yl]oxy]-ethyl]ethylamine (product name: IRGAFOS) 12); and 2,2'-methylenebis(4,6-di-tert-butylphenyl)octyl phosphite (product name: ADEKA STAB HP-10).

[0096] Organosulfur compounds are not limited to specific compounds; for example, the following compounds are preferred: dilauryl-3,3'-thiodipropionate (product name: Sumilizer TPL-R); dimyristyl-3,3'-thiodipropionate (product name: Sumilizer TPM); distearate-3,3'-thiodipropionate (product name: Sumilizer TPS); pentaerythritol tetra(3-laurylthiopropionate) (product name: Sumilizer TP-D); di(tridecyl)-3,3'-thiodipropionate (product name: Sumilizer TL); 2-mercaptobenzimidazole (product name: Sumilizer MB); di(tridecyl)-3,3'-thiodipropionate (product name: ADEKA STAB AO-503A); 1,3,5-tris-β-stearoylthiopropionyloxyethyl isocyanurate; di(dodecyl) 3,3'-thiodipropionate (product name: IRGANOX PS) 800FL); and 3,3'-thiobispropionate di(octadecyl) ester (product name: IRGANOX PS 802FL).

[0097] Of the antioxidants mentioned above, tetra[methylene-(3,5-di-tert-butyl-4-hydroxycinnamate)]methane is particularly preferred. Preferred amounts are 0.5 to 5 parts by weight, more preferably 1 to 3 parts by weight, per 100 parts by weight of resin A. Within this range, sufficient heat resistance and compatibility can be achieved. It should be noted that any single antioxidant can be used alone, or two or more can be used in combination.

[0098] Up to 50 parts by weight of filler, such as known silica, may be added to resin composition A per 100 parts by weight of resin A to enhance heat resistance.

[0099] If resin composition A is a solution, it is applied to a support by methods such as spin coating, roller coating, molding, printing, or dip coating. The applied resin composition A is then pre-baked at a temperature preferably 80 to 200°C, more preferably 100 to 180°C, depending on the solvent evaporation conditions, to evaporate the solvent. This forms resin composition layer A'.

[0100] On the other hand, if resin composition A is a film composition, resin composition layer A' can be formed on the support by lamination.

[0101] The resin composition layer A' formed on the support is further thermocured, thereby assuming the function of resin layer A. Thermocuring can be carried out using a hot plate or oven at a temperature typically between 100 and 350°C for 5 to 10 minutes, preferably between 150 and 300°C for 3 to 8 minutes. This curing reaction can also be achieved by heating the entire laminate after forming an uncured wafer laminate under the uncured resin composition layer A'.

[0102] The thickness of the resin layer A formed on the support is preferably 0.1 to 50 μm, more preferably 0.3 to 30 μm. Within this film thickness range, the light-shielding properties are sufficient and the film has preferred flatness.

[0103] Resin layer B

[0104] Resin layer B is a resin layer that contacts resin layer A formed on the support side of the wafer layer assembly, and will be removed by peeling after separation of the support.

[0105] The resin in resin layer B is a thermosetting silicone resin or a non-silicone thermoplastic resin (i.e., a thermoplastic resin that does not contain a siloxane backbone).

[0106] Thermosetting silicone resin is preferably formed to include repeating units represented by formula (2) and optional repeating units represented by formula (3) (hereinafter referred to as epoxy-modified silicone resin).

[0107]

[0108] In the formula, R 31 to R 34 independently represent a monovalent hydrocarbon group having 1 to 8 carbon atoms, and m is an integer of 1 to 100. Further, in the formula, A and B are numbers satisfying 0 < A ≤ 1, 0 ≤ B < 1 and A + B = 1, and X 1 and X 2 each represent a divalent organic group represented by the following formula (4).

[0109]

[0110] In the formula, Y 1 represents a single bond, methylene, propane-2,2-diyl, 1,1,1,3,3,3-hexafluoropropane-2,2-diyl or fluorene-9,9-diyl, R 41 and R 42 independently represent an alkoxy group or an alkyl group having 1 to 4 carbon atoms, and p and q independently represent 0, 1 or 2.

[0111] The epoxy-modified silicone resin preferably has an Mw of 3,000 to 500,000, more preferably 10,000 to 100,000. Desirably, the amount of the siloxane contained in the epoxy-modified silicone resin is controlled within 30 to 80% by weight in the resin.

[0112] The epoxy-modified silicone resin can be synthesized according to the method disclosed in, for example, JP-A 2013-110391.

[0113] If the resin layer B contains the epoxy-modified silicone resin, the resin layer B is preferably formed from a cured product of a resin composition B-1 containing the epoxy-modified silicone resin. Therefore, for thermal curing, the resin composition B-1 preferably includes at least one crosslinking agent selected from a phenolic compound having an average of two or more phenolic hydroxyl groups in one molecule and an epoxy compound having an average of two or more epoxy groups in one molecule.

[0114] The epoxy compound is not limited to a specific compound, and the examples shown in the description of the resin layer A can be used.

[0115] Phenolic compounds are not limited to specific compounds; for example, m-cresol or p-cresol phenolic resins (e.g., EP-6030G, ASAHI YUKIZAI CORPORATION), trifunctional phenolic compounds (e.g., Tris-P-PA, Honshu Chemical Industry Co., Ltd.), tetrafunctional phenolic compounds (e.g., TEP-TPA ASAHI YUKIZA CORPORATION), etc.

[0116] Based on 100 parts by weight of the epoxy-modified silicone resin, it contains preferably 0.1 to 50 parts by weight, more preferably 0.1 to 30 parts by weight, and even more preferably 1 to 20 parts by weight of a crosslinking agent. The crosslinking agent may be used alone or in combination of two or more of them.

[0117] In addition, based on 100 parts by weight of epoxy-modified silicone resin, resin composition B-1 may contain less than 10 parts by weight of curing catalyst, such as acid anhydride.

[0118] Resin composition B-1 may contain a solvent. Examples of solvents include ketones such as cyclohexanone, cyclopentanone, and methyl-2-n-pentyl ketone; alcohols such as 3-methoxybutanol, 3-methyl-3-methoxybutanol, 1-methoxy-2-propanol, and 1-ethoxy-2-propanol; ethers such as propylene glycol monomethyl ether, ethylene glycol monomethyl ether, propylene glycol monoethyl ether, ethylene glycol monoethyl ether, propylene glycol dimethyl ether, and diethylene glycol dimethyl ether; and esters such as propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, ethyl lactate, ethyl pyruvate, butyl acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, tert-butyl acetate, tert-butyl propionate, propylene glycol monotert-butyl ether acetate, and γ-butyrolactone. Any of these solvents may be used alone or in combination of two or more. The product contains preferably 40 to 1,000 parts by weight, more preferably 50 to 600 parts by weight, of solvent per 100 parts by weight of epoxy-modified silicone resin.

[0119] Resin composition B-1 can also be used as a solvent-free film composition.

[0120] Resin composition B-1 may contain surfactants and antioxidants to improve coatability and heat resistance. The surfactants and antioxidants may be those given as examples in the description of resin layer A.

[0121] For higher heat resistance, resin composition B-1 may contain up to 50 parts by weight of filler, such as silica, per 100 parts by weight of epoxy-modified silicone resin.

[0122] If resin composition B-1 is a solution, it is applied to resin layer A or resin composition layer A' by methods such as spin coating, roller coating, molding, printing, or dip coating, and pre-baked at a temperature preferably 60 to 160°C for 1 to 4 minutes, more preferably 80 to 140°C for 2 to 4 minutes, depending on the solvent evaporation conditions, thereby evaporating the solvent. This forms resin composition layer B1.

[0123] On the other hand, if the resin composition B-1 is a film composition, the resin composition layer B1 can be formed on the resin layer A or the resin composition layer A' by a lamination method.

[0124] Depending on the type of wafer used in the laminate, the required heat resistance during production can be relatively low. In this case, resin layer B can be formed from a resin composition B-1 that does not contain a crosslinking agent or curing catalyst.

[0125] If resin layer B contains epoxy-modified silicone resin, then for the purpose of bonding the support and silicon wafer as different types of substrates and for the purpose of suppressing warpage, the elastic modulus of resin layer B at 25°C is preferably 10 to 1,000 MPa. In this invention, elastic modulus refers to the elastic modulus (E') measured using a known dynamic viscoelastic analyzer under tensile conditions where the cured material used to form resin layer B has a rectangular shape with a thickness of 0.5 mm and a length of 30 mm × 10 mm, and a frequency of 1 Hz.

[0126] In addition, the resin of resin layer B can be a thermosetting silicone resin without epoxy groups (hereinafter referred to as epoxy-free silicone resin).

[0127] An example of an epoxy-free silicone resin is produced by curing a composition (hereinafter referred to as resin composition B-2) containing:

[0128] (b1) Organopolysiloxanes containing two or more alkenyl groups in one molecule;

[0129] (b2) Organohydropolysiloxanes containing two or more hydrogen atoms (Si-H groups) bonded to silicon atoms in one molecule; and

[0130] (b3) Platinum catalyst.

[0131] Component (b1) is an organopolysiloxane containing two or more alkenyl groups in one molecule, and for example, a straight-chain or branched diorganopolysiloxane containing two or more alkenyl groups in one molecule is given, having a composition of SiO 4 / 2Organopolysiloxanes with resin structures, such as those representing siloxane units (Q units). In particular, preferred examples of component (b1) are diorganopolysiloxanes having two or more alkenyl groups in one molecule, wherein the alkenyl content ratio is 0.6 to 9 mol%, or organopolysiloxanes having resin structures. In this invention, the alkenyl content ratio is the ratio (mol%) of the number of alkenyl groups to the number of silicon atoms in the molecule.

[0132] Specific examples of such organopolysiloxanes include those represented by formulas (b1-1), (b1-2), and (b1-3). Any one of these may be used, or two or more may be used in combination.

[0133]

[0134] In equations (b1-1) to (b1-3), R 101 To R 116 Independently representing a monovalent hydrocarbon group that is different from an aliphatic unsaturated hydrocarbon group, and Z 1 To Z 5 Independently represents a monovalent organic group containing an alkenyl group.

[0135] In equation (b1-1), a and b independently represent integers from 0 to 3. In equations (b1-1) and (b1-2), c 1 c 2 d 1 and d 2 To satisfy 0≤c 1 ≤10、2≤c 2 ≤10、0≤d 1 ≤100 and 0≤d 2 Integers ≤ 100, and a, b, c 1 c 2 d 1 and d 2 Preferably, the number of alkenyl groups is such that the alkenyl groups comprise 0.6 to 9 mol%.

[0136] In equation (b1-3), e is an integer from 1 to 3, and f 1 f 2 and f 3 To satisfy (f 2 +f 3 ) / f 1 =0.3 to 3.0 and f 3 / (f 1 +f 2 +f 3 () = numbers between 0.01 and 0.6.

[0137] Unlike aliphatic unsaturated hydrocarbon groups, the monovalent hydrocarbon group is preferably a group with 1 to 10 carbon atoms, and examples include alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, n-pentyl, and n-hexyl; cycloalkyl groups such as cyclopentyl and cyclohexyl; and aryl groups such as phenyl and tolyl. Among these groups, phenyl or alkyl groups such as methyl are preferred.

[0138] The monovalent organic group containing an alkenyl group is preferably an organic group with 2 to 10 carbon atoms, and examples include: alkenyl groups such as vinyl, allyl, hexenyl, and octenyl; (meth)acryloylalkyl groups such as acrylopropyl, acrylomethyl, and methacrylopropyl; (meth)acrylooxyalkyl groups such as acrylooxypropyl, acrylooxymethyl, and methacrylooxypropyl; and monovalent hydrocarbon groups containing an alkenyl group such as cyclohexenylethyl and vinyloxypropyl. Among these groups, vinyl is preferred from an industrial point of view.

[0139] In formula (b1-1), a and b are independent integers from 0 to 3. If a is 1 to 3, the molecular chain is end-capped by an alkenyl group; therefore, the reaction can be completed quickly by the highly reactive alkenyl group at the end of the molecular chain. Furthermore, from a cost perspective, a = 1 is preferred. The alkenyl-containing diorganopolysiloxane represented by formula (b1-1) is preferably in the form of an oil or raw rubber.

[0140] The organopolysiloxane represented by formula (b1-3) has SiO 4 / 2 The resin structure of the unit. In the formula, e independently represents an integer from 1 to 3, and for cost reasons, e = 1 is preferred. Preferably, the average value of e and f are... 3 / (f 1 +f 2 +f 3 The product of () is in the range of 0.02 to 1.5, more preferably 0.03 to 1.0. The organopolysiloxane having this resin structure can be used as a solution, wherein the organopolysiloxane is soluble in an organic solvent.

[0141] Component (b2) is a crosslinking agent and is an organohydrogen polysiloxane containing at least two, preferably three or more, hydrogen atoms (Si-H groups) bonded to silicon atoms in one molecule. The organohydrogen polysiloxane can be linear, branched, or cyclic. Any of the organohydrogen polysiloxanes can be used alone or in combination of two or more.

[0142] The organohydrogen polysiloxane preferably has a viscosity of 1 to 5,000 mPa·s, more preferably 5 to 500 mPa·s, at 25°C.

[0143] The resin composition B-2 contains component (b2) such that the total Si-H groups in component (b2) relative to the total alkenyl groups in component (b1) are preferably in the range of 0.3 to 10, more preferably 1.0 to 8.0 molar ratio (Si-H groups / alkenyl groups). If the molar ratio is 0.3 or higher, the crosslinking density will not become lower and there will be no problem of failure during the curing of the adhesive layer. If the molar ratio is 10 or lower, an extreme decrease in crosslinking density can be suppressed.

[0144] Component (b3) is a platinum group catalyst (i.e., a platinum group metal) and examples of such catalysts include chloroplatinic acid, an alcoholic solution of chloroplatinic acid, a product produced by the reaction of chloroplatinic acid with an alcohol, a product produced by the reaction of chloroplatinic acid with an olefin compound, and a product produced by the reaction of chloroplatinic acid with a vinyl-containing siloxane.

[0145] In resin composition B-2, component (b3) is contained in an effective amount, and its amount, based on the sum of components (b1) and (b2), is typically 1 to 5,000 ppm, preferably 5 to 2,000 ppm, of platinum group metals (by weight). If the amount is above 1 ppm, the hardness, crosslinking density, and retention power of the composition do not become lower. If the amount is below 5,000 ppm, the processing bath can be used for a longer period.

[0146] Resin composition B-2 may contain a reaction control agent (b4) as an optional component. The reaction control agent may be added as needed to prevent the processing solution from thickening or gelling before heat curing when preparing resin composition B-2 or applying it to a base material.

[0147] Specific examples include 3-methyl-1-butyn-3-ol, 3-methyl-1-pentyn-3-ol, 3,5-dimethyl-1-hexyn-3-ol, 1-ethyncyclohexanol, 3-methyl-3-trimethylsilyloxy-1-butyn, 3-methyl-3-trimethylsilyloxy-1-pentyn, 3,5-dimethyl-3-trimethylsilyloxy-1-hexyn, 1-ethyn-1-trimethylsilyloxycyclohexane, bis(2,2-dimethyl-3-butynoxy)dimethylsilane, 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane, and 1,1,3,3-tetramethyl-1,3-divinyldisiloxane. Among these, 1-ethyncyclohexanol and 3-methyl-1-butyn-3-ol are preferred.

[0148] In resin composition B-2, based on a total of 100 parts by weight of components (b1) and (b2), it typically contains 0 to 8 parts by weight, preferably 0.01 to 8 parts by weight, and more preferably 0.05 to 2 parts by weight of component (b4). If the amount is less than 8 parts by weight, the hardness of the composition will not become lower. If the amount is 0.01 parts by weight or more, sufficient reaction control is achieved.

[0149] Resin composition B-2 may contain an organic solvent (b5) as an arbitrary component. The organic solvent is not limited to a specific solvent and may be any solvent capable of dissolving components (b1) to (b4). Preferred examples include hydrocarbon solvents such as pentane, hexane, cyclohexane, isooctane, nonane, decane, p-menthane, pinene, isododecane, and limonene, as well as organosilicon solvents. If resin composition B-2 contains a solvent, resin layer B can be formed on a wafer by spin coating, roll coating, or other methods. The solvent is preferably 10 to 900 parts by weight, more preferably 25 to 400 parts by weight, and even more preferably 40 to 300 parts by weight per 100 parts by weight of component (b1).

[0150] A resin composition B-2 with a film-like structure can be formed.

[0151] For the purpose of improving heat resistance, known antioxidants can be added to resin composition B-2.

[0152] The epoxy-free silicone resin has a preferred Mw of 40,000 to 550,000, more preferably 50,000 to 500,000.

[0153] The cured product of resin composition B-2 preferably has a curing temperature of 1×10⁻⁶ at 25°C. 6 Up to 1×10 9 The elastic modulus of Pa. Compositions having an elastic modulus within this range are preferred, for example, because the composition can adequately withstand the polishing steps that thin the circuit board and does not adhere to the device in the process of reducing substrate warpage.

[0154] If relatively low heat resistance is required during production, resin layer B may contain a non-silicone thermoplastic resin. In this case, after separating the support, the resin on the wafer is peeled off, and then cleaned and removed with a solvent.

[0155] The non-silicone thermoplastic resin is particularly preferred to be a non-silicone thermoplastic resin having a glass transition temperature of about -80 to 120°C and a Mw of 20,000 to 200,000, more preferably 30,000 to 150,000.

[0156] Examples of non-silicone thermoplastic resins include non-silicone thermoplastic elastomers, such as polyolefin-based thermoplastic elastomers, polybutadiene-based thermoplastic elastomers, polystyrene-based thermoplastic elastomers, polystyrene-butadiene-based thermoplastic elastomers, polystyrene-olefin-based thermoplastic elastomers, and hydrogenated versions of these elastomers. Hydrogenated polystyrene elastomers with excellent heat resistance are particularly preferred. Specifically, Tuftek (registered trademark) (Asahi Kasei Chemicals Corporation), ESPOLEX (registered trademark) SB series (SUMITOMO CHEMICAL COMPANY, LIMITED), RABARON (registered trademark) (Mitsubishi Chemical Corporation), SEPTON (registered trademark) (KURARAY CO., LTD.), and DYNARON (registered trademark) (JSR Corporation) are given. Non-silicone thermoplastic resins include, for example, cyclic olefin polymers represented by ZEONEX (registered trademark) (ZEON CORPORATION) and cyclic olefin copolymers represented by TOPAS (registered trademark) (TOPAS ADVANCED POLYMERS GMBH).

[0157] The non-silicone thermoplastic resin is preferably a non-silicone thermoplastic elastomer. If a temporary adhesive layer comprising a composite containing a layer of non-silicone thermoplastic elastomer is used, the wafer can be easily separated from the support after production. Therefore, fragile wafers can be handled more easily.

[0158] If resin layer B comprises a non-silicone thermoplastic resin, then resin layer B is preferably a cured product of resin composition B-3 containing a non-silicone thermoplastic resin.

[0159] Resin composition B-3 may include antioxidants for improving heat resistance, surfactants for improving coatability, or release agents for improving separability. Examples of antioxidants include di-tert-butylphenol. Examples of surfactants include the fluoroorganosilicone surfactant X-70-1102 (Shin-Etsu Chemical Co., Ltd.). Examples of release agents include KF-96 (Shin-Etsu Chemical Co., Ltd.).

[0160] Resin composition B-3 may contain a solvent. The solvent may be a hydrocarbon solvent. Preferred examples include nonane, p-menthane, pinene, isooctane, toluene, xylene, and mesitylene. For coatability, nonane, p-menthane, isooctane, and mesitylene are more preferred. Any of these solvents may be used alone or in combination of two or more. The solvent is preferably present in a concentration of 250 to 3,500 parts by weight, more preferably 300 to 2,000 parts by weight, per 100 parts by weight of the non-silicone thermoplastic resin.

[0161] Resin composition B-3 can also be used as a solvent-free film composition.

[0162] If the resin composition B-3 is a solution, the solution is applied to the wafer by methods such as spin coating, roll coating, die coating, printing, or dip coating, and then heated using a hot plate or oven; thereby forming the resin layer B. In this case, the heating conditions are typically 1 to 10 minutes at 100 to 200°C, preferably 2 to 5 minutes at 130 to 190°C.

[0163] The resin layer B preferably has a thickness of 1 to 200 μm, more preferably 5 to 150 μm. A thickness within this range provides sufficient adhesion for bonding, and the bonded wafers exhibit high flatness.

[0164] Methods for producing thin wafers

[0165] As described above, the method for producing thin wafers according to the present invention includes the steps of separating a support from a wafer layer assembly and removing a residual resin layer from the wafer by peeling. Other steps may be known steps. The method for producing thin wafers according to the present invention may, for example, include steps (a) to (h).

[0166] Step (a) or (a')

[0167] Step (a) is the step of forming resin layer A on the support, and step (a') is the step of forming resin composition layer A' on the support. If the resin composition A used to form resin layer A is a solution, the solution is applied to the support by spin coating, roll coating, or other methods, and pre-baked at a temperature preferably 80 to 200°C, more preferably 100 to 180°C, depending on the solvent evaporation conditions, thereby evaporating the solvent. Resin composition layer A' is thus formed. If the resin composition A is a film composition, resin composition layer A' is formed on the support by a lamination method.

[0168] The resin composition layer A' formed on the support can function as resin layer A through thermosetting. A hot plate or oven can be used, typically at 100 to 350°C, preferably 150 to 300°C. The curing time is typically 1 to 10 minutes, preferably 2 to 8 minutes. This curing reaction can also be achieved by heating the entire wafer assembly after forming an uncured wafer assembly under the uncured resin composition layer A'.

[0169] Step (b) or (b')

[0170] Step (b) is the step of forming resin layer B on the surface of the wafer forming circuit, and step (b') is the step of forming resin layer B on resin layer A or resin composition layer A'. If resin compositions B-1 to B-3 are solutions, the solution is applied to the wafer by methods such as spin coating, roll coating, die coating, printing, dip coating, etc., and heated at 130 to 190°C using a hot plate or oven. Resin layer B is thus formed.

[0171] On the other hand, if resin compositions B-1 to B-3 are film compositions, resin layer B can be formed on a wafer by lamination.

[0172] Step (c) or (c')

[0173] Step (c) is the step of bonding resin layer A or resin composition layer A' to resin layer B under reduced pressure, and step (c') is the step of bonding resin layer B on the support and the surface of the wafer forming circuit under reduced pressure. The reduced pressure condition is preferably 0.1 to 100 Pa, more preferably 1 to 80 Pa. In this case, the substrate is uniformly pressed and bonded under reduced pressure within a temperature range preferably 40 to 240°C, more preferably 60 to 220°C.

[0174] Step (d)

[0175] Step (d) is the process of forming resin layer A by thermosetting the resin composition layer A' of the wafer layer assembly combined in step (c) or (c') to resin layer B, wherein after forming the wafer layer assembly, thermosetting is performed by heating at 120 to 260°C, preferably 150 to 250°C for 1 minute to 4 hours, preferably 3 minutes to 2 hours.

[0176] Step (e)

[0177] Step (e) is the step of processing the non-circuit-forming surface of a wafer, i.e., a wafer thinned by back-side grinding. This step includes various wafer-level processing. Examples include wafer surface processing, electrode formation, metal line formation, and protective film formation. More specifically, CVD and laser annealing for processing wafer surfaces, metal sputtering for forming electrodes, vapor deposition, wet etching for etching metal sputtered layers, applying a resist to be used as a mask for forming metal lines, patterning by exposure and development, resist separation, dry etching, forming a metal plating layer, forming an organic film for surface protection, silicon etching for TSV formation, forming an oxide film on a silicon surface, and other conventionally known processes are given. In the processes described above, the wafer processing body preferably has resistance in a high temperature range up to about 400°C, and preferably has strength and lifetime at temperatures above 300°C.

[0178] Step (f)

[0179] Step (f) is the step of separating the support from the thin wafer laminate processed in step (e). This separation step is typically carried out at a relatively low temperature, usually around room temperature, and preferably includes:

[0180] (f1) The step of attaching dicing tape to the processed surface (back side) of the processed wafer;

[0181] (f2) The step of vacuum suctioning the surface of the dicing tape to the adhesion surface; and

[0182] (f3) The step of separating the support from the thin wafer laminate by delivering, for example, a laser with a wavelength of 355 nm from the support side of the thin wafer laminate.

[0183] Therefore, the support can be easily separated from the wafer assembly, and the subsequent dicing step can be easily performed. It should be noted that the dicing tape can be a known tape formed from polyester or polyethylene film, etc.

[0184] Step (g)

[0185] Step (g) is the step of separating the remaining resin layers A and B that were not decomposed by the laser from the processed wafer after separating the support in step (f) by means of tape peeling or the like.

[0186] The separation step is performed at relatively low temperatures in the range of room temperature to approximately 60°C. In one example of the separation method in step (g), the wafer is horizontally fixed after step (f) and adhesive tape for separation is adhered to the exposed and undecomposed resin layer A; then the undecomposed resin layer A and resin layer B can be separated from the processed wafer by peeling off the adhesive tape.

[0187] The tape material can be any tape material that can be separated. In particular, tapes formed from silicone adhesives are preferred, and polyester film adhesive tapes No. 646S and No. 648 from TERAOKA SEISAKUSHO CO.,LTD. are preferred.

[0188] Furthermore, when separating the adhesive tape material by peeling, it is preferable to separate the tape material under a heated laminate. The heating temperature is preferably 30 to 60°C, more preferably 35 to 55°C. If a heated laminate is used, the adhesion between the resin layer B and the wafer is low, and therefore separation by peeling is easier.

[0189] Step (h)

[0190] Following step (g), it is preferable to perform a step of removing the temporary adhesive layer remaining on the non-circuit-forming surface of the separated wafer. On the circuit-forming surface of the wafer separated in step (g), resin layer B may partially remain, and in this case, resin layer B can be removed, for example, by cleaning the wafer.

[0191] In step (h), a cleaning agent that dissolves the components of resin layer B can be used; specifically, pentane, hexane, cyclohexane, decane, isononane, p-menthane, pinene, isododecane, limonene, etc., can be used. Any of these solvents can be used alone or in combination of two or more. If removal is difficult, a base or acid can be added to the solvent. Examples of bases include amines such as ethanolamine, diethanolamine, triethanolamine, triethylamine, and ammonia, and ammonium salts such as tetramethylammonium hydroxide. Examples of acids include organic acids such as acetates, oxalates, benzenesulfonates, and dodecylbenzenesulfonates. An additive may be present in a concentration of 0.01 to 10% by weight, preferably 0.1 to 5% by weight, and this is the concentration of the additive in a clear solution. To further remove residues, existing surfactants can be added. Cleaning methods can include cleaning methods using a solution with stirring, cleaning methods using spray, methods of immersion in a cleaning solution tank, etc. The temperature is preferably 10 to 80°C, more preferably 15 to 65°C, and if necessary, after dissolving resin layer B in its solution, it is finally cleaned with water or rinsed with alcohol and dried to obtain a thin wafer.

[0192] As described above, a support, a resin layer, and a substrate with circuitry on the surface are combined. The support is then separated, and the resin layer is further separated by peeling off adhesive tape. This process ultimately yields a thin wafer.

[0193] The process described above allows for easy bonding of the support and the wafer, the formation of a film with uniform thickness on substrates with large horizontal differences, the appropriate execution of the TSV formation step and the formation of lines on the back side of the wafer, high tolerance to wafer thermal processing such as CVD (chemical vapor deposition), easy separation of the wafer from the support, removal of the resist without contaminating the wafer, and enhanced productivity of thin wafers.

[0194] Example

[0195] The invention is described in more detail with reference to the preparation examples, embodiments, and comparative examples; however, the invention is not limited to these embodiments. It should be noted that the weight-average molecular weight (Mw) is a measurement relative to polystyrene obtained by GPC using THF as a solvent.

[0196] The compounds (M-1) to (M-6) and the acid-producing agent AG used in the following examples are as follows.

[0197]

[0198] [1] Preparation of resin composition

[0199] Preparation Example 1

[0200] Add 80 g (0.50 mol) of 1,5-dihydroxynaphthalene, 51.6 g (0.30 mol) of 2-hydroxy-6-naphthaldehyde, and 145 g of methyl cellosolve to a 1,000-mL flask. While stirring the mixture at 70°C, add 20 g of a methyl cellosolve solution containing 20% ​​by weight of p-toluenesulfonate. Stir the mixture for 6 hours as the temperature rises to 85°C, then cool to room temperature. The mixture is then diluted with 800 mL of ethyl acetate. After transferring the mixture to a separatory funnel, it is repeatedly cleaned with 200 mL of deionized water to remove the reaction catalyst and metallic impurities. Concentrate the resulting solution under reduced pressure; then add 600 mL of ethyl acetate to the residue and add the resulting mixture to 2,400 mL of hexane to precipitate the resin. Filter and collect the precipitated resin, then dry it under reduced pressure; thus obtaining resin A1 comprising repeating units represented by the following formula. Resin A1 has a Mw of 3,200 and a dispersity of 2.44 (Mw / Mn).

[0201] 20 parts by weight of resin A1, 1 part by weight of acid-generating agent AG, and 4 parts by weight of NIKALAC Mw390 (Sanwa Chemical Co., Ltd.) as a crosslinking agent were dissolved in 100 parts by weight of PGMEA containing 0.1 wt% FC-4430 (3M), and the mixture was filtered through a 0.1 μm filter made of fluororesin; thereby obtaining resin composition A1.

[0202]

[0203] Preparation Example 2

[0204] 80 g (0.50 mol) of 1,5-dihydroxynaphthalene, 9.0 g (0.30 mol) of paraformaldehyde, and 145 g of methyl cellosolve were added to a 1,000-mL flask. While stirring the mixture at 70°C, 20 g of a methyl cellosolve solution containing 20 wt% p-toluenesulfonate was added to the mixture. The mixture was stirred for 6 hours as the temperature was raised to 85°C, and then cooled to room temperature. The mixture was then diluted with 800 mL of ethyl acetate. After transferring the mixture to a separatory funnel, it was repeatedly cleaned with 200 mL of deionized water to remove the reaction catalyst and metallic impurities. The resulting solution was concentrated under reduced pressure; then 600 mL of ethyl acetate was added to the residue, and the resulting mixture was added to 2,400 mL of hexane to precipitate the resin. The precipitated resin was filtered and collected, and then dried under reduced pressure; thus obtaining resin A2 comprising repeating units represented by the following formula. Resin A2 has a Mw of 1,500 and a Mw / Mn of 2.20.

[0205] 20 parts by weight of resin A2, 1 part by weight of acid-generating agent AG, and 4 parts by weight of NIKALAC Mw390 (Sanwa Chemical Co., Ltd.) as a crosslinking agent were dissolved in 100 parts by weight of PGMEA containing 0.1 wt% FC-4430 (3M), and the mixture was filtered through a 0.1 μm filter made of fluororesin; thereby obtaining resin composition A2.

[0206]

[0207] Preparation Example 3

[0208] 72 g (0.50 mol) of 1-hydroxynaphthalene, 51.6 g (0.30 mol) of 2-hydroxy-6-naphthaldehyde, and 145 g of methyl cellosolve were added to a 1,000-mL flask, and while stirring the mixture at 70°C, 20 g of a methyl cellosolve solution containing 20 wt% p-toluenesulfonate was added. The mixture was stirred for 6 hours as the temperature was raised to 85°C, and then cooled to room temperature. The mixture was then diluted with 800 mL of ethyl acetate. After transferring the mixture to a separatory funnel, it was repeatedly cleaned with 200 mL of deionized water to remove the reaction catalyst and metallic impurities. The resulting solution was concentrated under reduced pressure; then 600 mL of ethyl acetate was added to the residue, and the resulting mixture was added to 2,400 mL of hexane to precipitate the resin. The precipitated resin was filtered and collected, and then dried under reduced pressure; thus obtaining resin A3 comprising repeating units represented by the following formula. Resin A3 has a Mw of 2,700 and a Mw / Mn of 2.61.

[0209] 20 parts by weight of resin A3, 1 part by weight of acid-producing agent AG, and 4 parts by weight of NIKALAC Mw390 (Sanwa Chemical Co., Ltd.) as a crosslinking agent were dissolved in 100 parts by weight of PGMEA containing 0.1 wt% FC-4430 (3M), and the mixture was filtered through a 0.1 μm filter made of fluororesin; thereby obtaining resin composition A3.

[0210]

[0211] Preparation Example 4

[0212] 43.1 g of compound (M-1), 90.8 g of compound (M-3), 135 g of toluene, and 0.04 g of chloroplatinic acid were added to a 5-L flask equipped with a stirrer, thermometer, nitrogen purging device, and reflux condenser, and the mixture was heated to 80°C. Then, 13.6 g of compound (M-5) was added dropwise to the flask over 1 hour. During this process, the temperature in the flask was raised to 85°C. After the dropwise addition, the mixture was aged at 80°C for another 2 hours, and toluene was distilled off, followed by the addition of 80 g of cyclohexanone; thus, a resin solution containing cyclohexanone as a solvent and having a resin solids concentration of 50% by weight was obtained. The resin in the resin solution had a Mw of 50,000. 7.5g of epoxy crosslinking agent EOCN-1020 (Nippon Kayaku Co., Ltd.) as a crosslinking agent, 0.2g of BSDM (bis(tert-butylsulfonyl)diazomethane (Wako PureChemical Corporation)) as a curing catalyst, and 0.1g of tetra[methylene(3,5-di-tert-butyl-4-hydroxycinnamate)]methane (product name: ADEKA STAB AO-60) as an antioxidant were added to 50g of the resin solution, and the mixture was filtered through a 1μm membrane filter to obtain resin composition B1.

[0213] Preparation Example 5

[0214] 84.1 g of compound (M-2) and 250 g of toluene were added to a 5-L flask equipped with a stirrer, thermometer, nitrogen purging device, and reflux condenser and dissolved. Then, 121.0 g of compound (M-3) and 21.5 g of compound (M-4) were added, and the mixture was heated to 60°C. After this, 1 g of carbon-supported platinum catalyst (5 wt%) was added, and after confirming that the internal reaction temperature had risen to 65-67°C, the temperature was further increased to 90°C, and the mixture was aged for 3 hours. Next, after cooling the mixture to room temperature, 250 g of methyl isobutyl ketone (MIBK) was added, and the reaction solution was filtered under pressure to remove the platinum catalyst. The solvent in the resin solution was distilled off under reduced pressure, and 150 g of propylene glycol monomethyl ether acetate (PGMEA) was added, thereby obtaining a resin solution with a solids content concentration of 60 wt%, including PGMEA as a solvent. The resin in the resin solution had a Mw of 45,000. Add 9g of the tetrafunctional phenolic compound TEP-TPA (ASAHI YUKIZAI CORPORATION) as a crosslinking agent and 0.2g of tetrahydrophthalic anhydride (RIKACID HH-A, New Japan Chemical Co., Ltd.) as a curing catalyst to 100g of the resin solution, and filter the mixture through a 1μm membrane filter to obtain resin composition B2.

[0215] Preparation Example 6

[0216] 84.1 g of compound (M-2) and 170 g of toluene were added to a 5-L flask equipped with a stirrer, thermometer, nitrogen purging device, and reflux condenser and dissolved. Then, 60.5 g of compound (M-3) and 24.2 g of compound (M-4) were added, and the mixture was heated to 60°C. After this, 1 g of carbon-supported platinum catalyst (5 wt%) was added, and after confirming that the internal reaction temperature had risen to 65-67°C, the temperature was further increased to 90°C, and the mixture was aged for 3 hours. Next, after cooling the mixture to room temperature, 170 g of MIBK was added, and the reaction solution was filtered under pressure to remove the platinum catalyst. The solvent in the resin solution was distilled off under reduced pressure, and 110 g of PGMEA was added, thereby obtaining a resin solution with a solids content concentration of 60 wt%, including PGMEA as a solvent. The resin in the resin solution had a Mw of 42,000. Add 9g of the tetrafunctional phenolic compound TEP-TPA (ASAHI YUKIZAICORPORATION) as a crosslinking agent and 0.2g of tetrahydrophthalic anhydride (RIKACID HH-A, New Japan Chemical Co., Ltd.) as a curing catalyst to 100g of the resin solution, and filter the mixture through a 1μm membrane filter to obtain resin composition B3.

[0217] Preparation Example 7

[0218] 84.1 g of compound (M-2) and 150 g of toluene were added to a 5-L flask equipped with a stirrer, thermometer, nitrogen purging device, and reflux condenser and dissolved. Then, 30.3 g of compound (M-3) and 25.5 g of compound (M-4) were added, and the mixture was heated to 60°C. After this, 1 g of carbon-supported platinum catalyst (5 wt%) was added, and after confirming that the internal reaction temperature had risen to 65-67°C, the temperature was further increased to 90°C, and the mixture was aged for 3 hours. Next, after cooling the mixture to room temperature, 150 g of MIBK was added, and the reaction solution was filtered under pressure to remove the platinum catalyst. The solvent in the resin solution was distilled off under reduced pressure, and 90 g of PGMEA was added, thereby obtaining a resin solution with a solid content concentration of 60 wt%, including PGMEA as a solvent. The resin in the resin solution had a Mw of 35,000. 9g of a tetrafunctional phenolic compound TEP-TPA (ASAHI YUKIZAICORPORATION) as a crosslinking agent and 0.2g of tetrahydrophthalic anhydride (RIKACID HH-A, New Japan Chemical Co., Ltd.) as a curing catalyst were added to 100g of the resin solution, and the mixture was filtered through a 1μm membrane filter to obtain resin composition B4.

[0219] Preparation Example 8

[0220] 84.1 g of compound (M-2) and 120 g of toluene were added to a 5-L flask equipped with a stirrer, thermometer, nitrogen purging device, and reflux condenser and dissolved. Then, 9.1 g of compound (M-3) and 26.5 g of compound (M-4) were added, and the mixture was heated to 60°C. After this, 1 g of carbon-supported platinum catalyst (5 wt%) was added, and after confirming that the internal reaction temperature had risen to 65-67°C, the temperature was further increased to 90°C, and the mixture was aged for 3 hours. Next, after cooling the mixture to room temperature, 120 g of MIBK was added, and the reaction solution was filtered under pressure to remove the platinum catalyst. The solvent in the resin solution was distilled off under reduced pressure, and 75 g of PGMEA was added, thereby obtaining a resin solution with a solid content concentration of 60 wt%, including PGMEA as a solvent. The resin in the resin solution had a Mw of 28,000. Add 9g of the tetrafunctional phenolic compound TEP-TPA (ASAHI YUKIZAICORPORATION) as a crosslinking agent and 0.2g of tetrahydrophthalic anhydride (RIKACID HH-A, New Japan Chemical Co., Ltd.) as a curing catalyst to 100g of the resin solution, and filter the mixture through a 1μm membrane filter to obtain resin composition B5.

[0221] Preparation Example 9

[0222] 84.1 g of compound (M-2) and 110 g of toluene were added to a 5-L flask equipped with a stirrer, thermometer, nitrogen purging device, and reflux condenser and dissolved. Then, 26.9 g of compound (M-4) was added and the mixture was heated to 60°C. After this, 1 g of carbon-supported platinum catalyst (5 wt%) was added, and after confirming that the internal reaction temperature had risen to 65-67°C, the temperature was further increased to 90°C, and the mixture was aged for 3 hours. Next, after cooling the mixture to room temperature, 110 g of MIBK was added, and the reaction solution was filtered under pressure to remove the platinum catalyst. The solvent in the resin solution was distilled off under reduced pressure, and 70 g of PGMEA was added, thereby obtaining a resin solution with a solid content concentration of 60 wt%, including PGMEA as a solvent. The resin in the resin solution had a Mw of 25,000. 9g of a tetrafunctional phenolic compound TEP-TPA (ASAHI YUKIZAI CORPORATION) as a crosslinking agent and 0.2g of tetrahydrophthalic anhydride (RIKACID HH-A, New Japan Chemical Co., Ltd.) as a curing catalyst were added to 100g of the resin solution, and the mixture was filtered through a 1μm membrane filter to obtain resin composition B6.

[0223] Preparation Example 10

[0224] 28.0 g of compound (M-2) and 130 g of toluene were added to a 5-L flask equipped with a stirrer, thermometer, nitrogen purging device, and reflux condenser and dissolved. Then, 100.9 g of compound (M-3) and 4.5 g of compound (M-4) were added, and the mixture was heated to 60°C. After this, 1 g of carbon-supported platinum catalyst (5 wt%) was added, and after confirming that the internal reaction temperature had risen to 65-67°C, the temperature was further increased to 90°C, and the mixture was aged for 3 hours. Next, after cooling the mixture to room temperature, 130 g of MIBK was added, and the reaction solution was filtered under pressure to remove the platinum catalyst. The solvent in the resin solution was distilled off under reduced pressure, and 80 g of PGMEA was added, thereby obtaining a resin solution with a solid content concentration of 60 wt%, including PGMEA as a solvent. The resin in the resin solution had a Mw of 52,000. Add 9g of the tetrafunctional phenolic compound TEP-TPA (ASAHI YUKIZAICORPORATION) as a crosslinking agent and 0.2g of tetrahydrophthalic anhydride (RIKACID HH-A, New Japan Chemical Co., Ltd.) as a curing catalyst to 100g of the resin solution, and filter the mixture through a 1μm membrane filter to obtain resin composition B7.

[0225] Preparation Example 11

[0226] 25 g of hydrogenated polystyrene thermoplastic resin SEPTON 4033 (KURARAY CO.,LTD., polystyrene-poly(ethylene-propylene) block-polystyrene copolymer, containing 30 wt% styrene) and 25 g of hydrogenated polystyrene thermoplastic resin SEPTON 8076 (KURARAY CO.,LTD., polystyrene-poly(ethylene-butene) block-polystyrene copolymer, containing 30 wt% styrene) were dissolved in 150 g of mesitylene to obtain a mesitylene solution containing 25 wt% SEPTON 4033 / 8076. The obtained solution was filtered through a 0.2 μm membrane filter to obtain resin composition B8.

[0227] Preparation Example 12

[0228] A solution containing 200 parts by weight of toluene and 100 parts by weight of polydimethylsiloxane having a number average molecular weight (Mn) of 30,000 and 2.5 mol% vinyl groups on molecular side chains was mixed with 40 parts by weight of compound (M-6) and 0.7 parts by weight of acetylenol. Additionally, 0.2 parts by weight of platinum catalyst CAT-PL-5 (Shin-Etsu Chemical Co., Ltd.) was added, and the mixture was filtered through a 0.2 μm membrane filter; thereby obtaining a thermosetting organosilicon resin composition B9. In resin composition B9, the molar ratio of organohydrogen polysiloxanes containing Si-H groups to the content of alkenyl groups in organopolysiloxanes is 1.1.

[0229] [2] Production and evaluation of thin wafers

[0230] Examples 1 to 10, Comparative Examples 1 to 2

[0231] On a glass plate with a diameter of 200 mm (thickness: 500 μm), resin composition A1, A2 or A3 is spin-coated and heated on a hot plate at 180°C for 2 minutes, and then at 250°C for 5 minutes, thus forming a film of material for resin layer A with the thickness shown in Tables 1 and 2.

[0232] Additionally, a silicon wafer with a diameter of 200 mm (thickness: 725 μm) is provided, on which copper pillars with a height of 10 μm and a diameter of 40 μm are formed over the entire surface. Resin compositions B1, B2, B3, B4, B5, B6, B7, B8, or B9 are applied to the surface of the copper pillars or resin layer A by spin coating. Resin compositions B1 to B7 are then heated on a hot plate at 150°C for 5 minutes, resin composition B8 is heated on a hot plate at 150°C for 5 minutes, and resin composition B9 is not heated; thus, resin layer B is formed with the thicknesses shown in Tables 1 and 2.

[0233] The resin surface or resin layer B and the copper pillar surface of the wafer are bonded together in a vacuum bonding apparatus (EVG520IS, EVG) under reduced pressure conditions below 1 Pa and the conditions shown in Tables 1 and 2, according to either a combination of glass plate-resin layer A and resin layer B-wafer or a combination of glass plate-resin layer A-resin layer B and wafer. This produces a wafer laminate.

[0234] These bonded substrates were then tested as shown below. The results are shown in Tables 1 and 2. Evaluation was performed according to the following procedures.

[0235] (1) Adhesion test

[0236] Wafers with a diameter of 200 mm were bonded together using EVG's EVG520IS wafer bonding system. The bonding temperature was the value shown in Tables 1 and 2, the pressure in the bonding chamber was below 1 Pa, and the load was 5 kN in Examples 1 to 8 and Comparative Examples 1 and 2, 20 kN in Example 9, and 3 kN in Example 10. After bonding, the temperature was lowered to room temperature, and the bonding status at the interface was observed visually and with an optical microscope. Wafers without abnormalities such as bubbles at the interface were rated as good and marked "○", while wafers with abnormalities were rated as poor and marked "×".

[0237] (2) Tests on tolerance to backside grinding

[0238] The back side of the silicon wafer was polished using a diamond wheel in a polishing machine (DAG810, DISCO). After polishing the wafer until the final substrate thickness reached 50 μm, the wafer was examined using an optical microscope (100x magnification) to check for abnormalities such as cracks or separation. Wafers without abnormalities were rated as good and marked "○", while wafers with abnormalities were rated as poor and marked "×".

[0239] (3) Tolerance testing in CVD

[0240] The laminate, after back-side grinding of the silicon wafer, is introduced into a CVD apparatus, and a SiO2 film with a thickness of 1 μm or 2 μm is formed in the experiment. The appearance of any abnormalities is examined during the experiment. Laminates containing a 2 μm thick SiO2 film with no appearance abnormalities are evaluated as good and marked "○"; laminates containing a SiO2 film with a thickness of up to 1 μm without abnormalities are marked "△"; and laminates containing a 1 μm thick SiO2 film with appearance abnormalities such as porosity, wafer swelling, or wafer damage are evaluated as poor and marked "×". The CVD tolerance test is performed under the following conditions:

[0241] Device Name: Plasma CVD PD270STL (Samco Inc.)

[0242] RF: 500W, Internal pressure: 40Pa

[0243] TEOS (Tetraethyl Orthosilicate): O2 = 20 sccm: 680 sccm

[0244] (4) Test of the separability of the support

[0245] The separability of the support was evaluated using the following method. First, after a robustness test in CVD (where the wafer was thinned to 50 μm), slicing tape was adhered to the wafer side of the wafer laminate using a slicing frame, and the surface of the slicing tape was fixed to a suction plate via a vacuum section. After this, the entire surface was irradiated from the support side with a 355 nm laser. In Comparative Example 2, no laser irradiation was performed, and the glass substrate was separated by lifting a point of the glass with tweezers. If the glass substrate was separated without damaging the support or wafer with a thickness of 50 μm, it was marked with “○”, and if an abnormality such as cracking occurred, it was evaluated as poor and marked with “×”.

[0246] (5) Test for peelability and separability

[0247] The peelability of resin layer B produced by resin compositions B1 to B9 was evaluated using the following method. First, after a peelability test of the support, a release tape was applied to the surface of the adhesive layer in the wafer assembly. Then, the release tape was lifted to separate the adhesive layer and the wafer at the interface. It should be noted that the peelability test was conducted at room temperature (23°C) in Examples 1 to 5, 8, and 10 and Comparative Examples 1 and 2, on a heated workbench at 40°C in Examples 7 and 9, and on both a heated workbench at room temperature (23°C) and 40°C in Example 6. Here, a wafer with a thickness of 50 μm that can be separated without breakage or residue is shown as "○", a wafer without breakage but with residue is shown as "△", and a wafer with abnormalities such as breakage or residue is evaluated as poor and shown as "×".

[0248] (6) Peel-off force test

[0249] Resin compositions B1 to B9 were applied to a silicon wafer by spin coating and heated on a hot plate at 150°C for 5 minutes, followed by heating at 180°C for another hour. This cured the corresponding adhesive layers to the film thicknesses shown in Tables 1 and 2. Five polyimide tapes (each with a length of 150 mm and a width of 25 mm) were then applied to the adhesive layers on the wafer, and the adhesive layers in the un-tape areas were removed. Using AUTOGRAPH (AG-1), SHIMADZU CORPORATION separated the tapes from one end at 180° for 120 mm at a rate of 300 mm / min, and the average force applied during this separation (120 mm stroke × 5 times) was considered the separation force of the adhesive layer. It should be noted that the separation force tests in Examples 1 to 5, 8 and 10 and Comparative Examples 1 and 2 were conducted at room temperature (23°C), in Examples 7 and 9 on a heated workbench at 40°C, and in Example 6 on both a heated workbench at room temperature (23°C) and a heated workbench at 40°C.

[0250] (7) Transmittance test

[0251] Resin compositions A1, A2, and A3 were applied to a 0.3 μm thickness on a 500 μm thick glass substrate by spin coating. The mixtures were then cured by heating on a hot plate at 180°C for 2 minutes, followed by heating at 250°C for 5 minutes. The transmittance (wavelength 355 nm) was then measured using a spectrophotometer (U-4100, Hitachi High-Tech Science Corporation). Products with a transmittance of less than 20% were rated as good and marked "○", while products with a transmittance greater than 20% were rated as poor and marked "×".

[0252] The transmittance of resin layer A, formed on a support substrate using resin compositions A1, A2, and A3, was measured. The maximum absorption wavelength was confirmed to be in the range of 300 to 500 nm.

[0253] (8) Measurement of elastic modulus

[0254] Measuring sheets with a thickness of 0.5 mm and a size of 30 mm × 10 mm were obtained by curing resin compositions B1 to B9 at 180 °C for 10 minutes. Measuring sheets with a thickness of 0.5 mm and a size of 30 mm × 10 mm were also obtained by heating resin composition B8 at 180 °C for 10 minutes. Using the produced measuring sheets, measurements were performed using a dynamic mechanical analyzer (DMA7100, Hitachi High-Tech Science Corporation) at a frequency of 1 Hz and a temperature rise rate of 3 °C / min within a temperature range of 0 to 300 °C. The value obtained at 25 °C was used as the elastic modulus (E').

[0255] (9) Measurement of tensile breaking strength

[0256] Dumbbell-shaped sheets with shape number 5 were obtained from rectangular sheets with a thickness of 0.4 mm and dimensions of 200 mm × 40 mm by curing resin compositions B1 to B9 at 180°C for 10 minutes. Dumbbell-shaped sheets with shape number 5 were also obtained from rectangular sheets with a thickness of 0.4 mm and dimensions of 200 mm × 40 mm by heating resin composition B8 at 180°C for 10 minutes. Using the produced measuring sheets, tensile testing was performed using a tensile tester (V10D, Toyo Seiki Seisakusho, Ltd.) at a tensile rate of 50 mm / min, and the strength at which the measuring sheet broke was used as the breaking strength (MPa).

[0257] Table 1

[0258]

[0259] Table 2

[0260]

[0261] The above results indicate that in Examples 1 to 10, temporary adhesion, support separation, and peeling separation were easy. On the other hand, in Comparative Example 1, the support did not separate and broke after laser irradiation, and in Comparative Example 2, the support did not separate and broke. In Examples 1 to 10, measurements of the wafer surface after separation using SEM-EDX testing showed that metal contamination (metals: Ca, K, Na, Mg, Mn, Pb) was less than or equal to the problematic level.

[0262] Japanese Patent Application No. 2018-164373 is incorporated herein by reference.

[0263] Although some preferred embodiments have been described, many modifications and alterations can be made to them in accordance with the foregoing teachings. Therefore, it is understood that the invention may be practiced beyond the specific description without departing from the scope of the appended claims.

Claims

1. A method for producing thin wafers, comprising: The support is separated from the wafer laminate by irradiating the wafer laminate with light from the support side of the wafer laminate, wherein the wafer laminate includes a support, a temporary adhesive layer formed on the support, and a wafer including a circuit plane facing the adhesive layer stacked on its surface, and wherein the temporary adhesive layer from the support side sequentially includes only a light-shielding resin layer A and a resin layer B including a thermosetting silicone resin. After the above separation, resin layers B and A, which were not exposed to light during the separation step, are separated by attaching tape to resin layer A and peeling resin layers A and B from the wafer. Wherein resin layer A comprises a cured resin composition A containing a crosslinking agent and resin A, wherein resin A comprises repeating units represented by the following formula (1): Where R 1 To R 3 R independently represents a hydrogen atom, a hydroxyl group, or a monovalent organic group of 1 to 20 carbon atoms. 1 To R 3 At least one of them is a hydroxyl group, R 4 A monovalent organic group representing a hydrogen atom or 1 to 30 carbon atoms that may have substituents. Resin layer B comprises an epoxy-modified silicone resin containing a siloxane backbone and epoxy groups, wherein the amount of siloxane in the epoxy-modified silicone resin is 40-63% by weight of the resin. The epoxy-modified silicone resin comprising a siloxane backbone and epoxy groups comprises repeating units represented by formula (2) and optionally repeating units represented by formula (3): Where R 31 To R 34 Let X represent a monovalent hydrocarbon group with 1 to 8 carbon atoms, m represent an integer from 1 to 100, A and B be numbers satisfying 0 < A ≤ 1, 0 ≤ B < 1, and A + B = 1, and X 1 and X 2 Each represents a divalent organic group represented by the following formula (4): Among them, Y 1 Represents a single bond, methylene, propane-2,2-diyl, 1,1,1,3,3,3-hexafluoropropane-2,2-diyl, or fluorene-9,9-diyl, R 41 and R 42 The alkoxy or alkyl group with 1 to 4 carbon atoms is represented independently, and p and q represent 0, 1 or 2 independently.

2. The method for producing thin wafers according to claim 1, wherein the composite layer is exposed to a temperature of 30 to 60°C when separating the resin layer B from the wafer by peeling.

3. The method for producing thin wafers according to claim 1, wherein the light-shielding resin layer A has a transmittance of less than 20% at a wavelength of 355 nm and a maximum absorption wavelength of 300 to 500 nm.

4. The method for producing thin wafers according to claim 1, wherein the resin composition A further comprises an acid-generating agent.

5. The method for producing thin wafers according to claim 1, wherein the resin composition A further comprises an organic solvent.

6. The method for producing thin wafers according to claim 1, wherein the resin layer A has a thickness of 0.1 to 50 μm.

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