Temporary adhesive for wafer processing, wafer laminate, and method for manufacturing thin wafer

Abstract

The present invention is a temporary adhesive for wafer processing, the temporary adhesive for wafer processing being used for temporarily adhering a wafer to a support, the temporary adhesive for wafer processing comprising a curable silicone resin composition that can be cured by a hydrosilylation reaction, the curable silicone resin composition contains a phenolic antioxidant that does not contain phosphorus atoms and sulfur atoms. Thus, provided are a temporary adhesive for wafer processing, a wafer laminate, and a method for manufacturing a thin wafer, the temporary adhesive for wafer processing having sufficient substrate retention after wafer bonding even when a high step substrate is used, having excellent wafer processing resistance after wafer bonding, and being capable of improving the yield of the wafer. The wafer peelability after processing, particularly the thermal stability of the wafer peelability, is excellent, and the cleaning removability after peeling is also excellent.

Description

Technical Field

[0001] The present invention relates to a temporary adhesive for wafer processing, a wafer stack and a method for manufacturing a thin wafer. Background Art

[0002] In order to achieve further high density and large capacity, three-dimensional semiconductor mounting is required. Three-dimensional mounting technology refers to a semiconductor manufacturing technology that thins a semiconductor chip, further connects it through silicon via electrodes (TSV: through silicon via), and stacks it into multiple layers. In order to realize this technology, it is necessary to thin the substrate on which the semiconductor circuit is formed by grinding the non-circuit forming surface (also called the "back side"), and further perform a process of forming electrodes including TSV on the back side. In the past, in the back grinding process of the silicon substrate, a back protective tape was affixed to the opposite side of the grinding surface to prevent the wafer from being damaged during grinding. However, this tape uses an organic resin film as a support substrate. Although it has flexibility, its strength and heat resistance are not sufficient, and it is not suitable for the TSV formation process or the back wiring layer formation process.

[0003] Therefore, a system is proposed that is capable of bonding a semiconductor substrate to a support such as silicon or glass via an adhesive layer, thereby being able to withstand the processes of back grinding, TSV, or back electrode formation. The adhesive layer used to bond the substrate to the support is important. It needs to be able to bond the substrate to the support without a gap and have sufficient durability to withstand subsequent processes. Furthermore, it needs to be able to easily peel off the thin wafer from the support at the end. Therefore, since it will be peeled off at the end, this adhesive layer is also referred to as a temporary adhesive layer in this specification.

[0004] So far, as known temporary adhesive layers and methods for peeling them off, there have been proposed a technology that irradiates an adhesive containing a light-absorbing substance with high-intensity light to decompose the adhesive layer, thereby peeling the adhesive layer from the support (Patent Document 1); and a technology that uses a heat-melting hydrocarbon compound as an adhesive and performs bonding and peeling in a heated and molten state (Patent Document 2). The former technology requires expensive equipment such as lasers, and there are problems such as a longer processing time for each substrate. In addition, although the latter technology can be controlled only by heating and is relatively simple, its thermal stability at high temperatures above 200°C is not sufficient, so its scope of application is narrow. In addition, these temporary adhesive layers are not suitable for forming a uniform film thickness on high-step difference substrates and for completely bonding to the support.

[0005] Further, a technique of using a silicone adhesive for a temporary adhesive layer has been proposed. It uses an addition-curable silicone adhesive to adhere a substrate to a support, and upon peeling, the substrate is separated from the support by immersing in a chemical agent that dissolves or decomposes the silicone resin (Patent Document 3). Therefore, the peeling requires a very long time, and it is difficult to apply to actual manufacturing processes. Further, after peeling, it also requires a long time to clean the silicone adhesive that remains on the substrate in the form of residues, and there is a technical problem in terms of cleaning removal.

[0006] For the above technical problems, it has been conventionally known to use a curable silicone composition containing a non-functional polyorganosiloxane for a temporary adhesive layer (Patent Documents 4 and 5). According to this composition, by joining a substrate to a support via a temporary adhesive layer, the adhesion between the substrate and the temporary adhesive layer that can withstand processing of the substrate is obtained, and on the other hand, upon peeling the support from the substrate, the temporary adhesive layer can be peeled in a state of selectively adhering to the support side, and therefore, after peeling, the temporary adhesive layer hardly remains on the substrate. Thus, the cleaning removal of the substrate after peeling can be greatly improved, and it is possible to satisfy both the above peeling property and the cleaning removal property.

[0007] However, after joining the substrate to the support, in the substrate processing process before peeling, when exposed to a high temperature of more than 200°C in the air for a long time, the silicone of the temporary adhesive layer is oxidatively deteriorated by oxygen in the air, and particularly, problems such as adhesion of the substrate to the temporary adhesive layer occur near the outer peripheral portion of the joined substrate. Since this causes abnormalities such as a part of the temporary adhesive layer remaining on the substrate after peeling (residue generation) or a substrate that has been thinned is broken at the time of peeling, it is required to be solved as soon as possible.

[0008] Prior Art Documents

[0009] Patent Documents

[0010] Patent Document 1: Japanese Patent Application Publication No. 2004-64040

[0011] Patent Document 2: Japanese Patent Application Publication No. 2006-328104

[0012] Patent Document 3: U.S. Patent No. 7541264

[0013] Patent Document 4: International Publication No. WO2021 / 112070

[0014] Patent Document 5: International Publication No. WO2021 / 220929 SUMMARY

[0015] (1) Technical Problem to be Solved

[0016] The present invention is completed in view of the above-mentioned technical problems, and its purpose is to provide a temporary adhesive for wafer processing, a wafer stack, and a method for manufacturing a thin wafer using a temporary adhesive for wafer processing. The temporary adhesive for wafer processing has sufficient substrate retention after bonding even when a high-step-difference substrate is used, and is highly suitable for the wafer back grinding process, TSV formation process, and wafer back wiring process. Even after bonding, after undergoing a high-temperature and long-term heat process in the air, peeling in the peeling process will be easier, and the residue cleaning property of the substrate after peeling is also excellent, etc., which helps to improve the productivity of thin wafers.

[0017] (2) Technical solution

[0018] In order to solve the above technical problems, the present invention provides a temporary adhesive for wafer processing, which is a temporary adhesive for wafer processing used for temporarily bonding a wafer to a support body, characterized in that the temporary adhesive for wafer processing is composed of a curable silicone resin composition that can be cured by a hydrosilation reaction, and the curable silicone resin composition contains a phenolic antioxidant that does not contain phosphorus atoms and sulfur atoms.

[0019] The temporary adhesive for wafer processing of the present invention can fully retain the substrate after bonding even when using a high-step substrate, and can improve the process suitability for the wafer back grinding process, TSV formation process, and wafer back wiring process. In addition, even if such a temporary adhesive for wafer processing is subjected to a high-temperature and long-term heat process in air after bonding, peeling in the peeling process will be easier, and the residue cleaning property of the substrate after peeling is also excellent, which helps to improve the productivity of thin wafers.

[0020] Furthermore, in the present invention, the curable silicone resin composition preferably comprises:

[0021] (A) 100 parts by mass of an organopolysiloxane having two or more alkenyl groups in one molecule;

[0022] (B) an organohydrogenpolysiloxane containing two or more hydrogen atoms bonded to silicon atoms (SiH groups) in one molecule, wherein the total molar ratio of the SiH groups in the component (B) to the total molar ratio of the alkenyl groups in the component (A) is 0.3 to 10;

[0023] (C) 0.1 to 200 parts by mass of a non-functional organopolysiloxane;

[0024] (D) a hydrosilylation catalyst, in an amount of 0.1 to 5,000 ppm in terms of metal atomic weight relative to the total mass of components (A), (B), and (C); and

[0025] (E) The phenolic antioxidant is present in an amount of 1 to 100,000 ppm based on the total mass of the components (A), (B), and (C).

[0026] In the temporary adhesive for wafer processing of the present invention, more specifically, the curable silicone resin composition may contain the above-mentioned components.

[0027] In this case, the amount of the component (B) is more preferably such that the total molar ratio of the SiH groups in the component (B) to the total molar ratio of the alkenyl groups in the component (A) is 0.3 to 5.0.

[0028] Furthermore, it is preferred that the curable silicone resin composition be curable by light and / or heat.

[0029] Thus, by making the curable silicone resin composition a material that is cured by light and / or heat, curing can be performed more simply and efficiently.

[0030] Furthermore, the phenolic antioxidant as the component (E) is preferably a hindered phenolic antioxidant.

[0031] Such hindered phenol-based antioxidants are preferred because they easily exhibit an antioxidant effect.

[0032] Furthermore, it is preferred that the non-functional organopolysiloxane of the component (C) is dimethylpolysiloxane, and the viscosity of a 30% by mass toluene solution of the component (C) at 25° C. is 100 to 500,000 mPa·s.

[0033] Such a viscosity range has an appropriate molecular weight, so it is preferred because it does not volatilize during heat curing of the silicone resin composition, thereby preventing the effect from being difficult to obtain, or does not cause wafer cracking during wafer thermal processes such as CVD, and has good handleability and coating properties.

[0034] The curable silicone resin composition containing the phenolic antioxidant preferably further contains 0.001 to 10 parts by mass of a hydrosilylation reaction control agent as the component (F) based on the total mass of the components (A), (B), and (C).

[0035] By setting the content of the component (F) within this range, the composition can be used for a long time, long-term storage stability can be obtained, and good curability and workability can be achieved.

[0036] Furthermore, after curing, the curable silicone resin composition containing the phenolic antioxidant preferably has a 180° peel strength of 2 gf or more and 100 gf or less of a 25 mm wide test piece at 25° C. relative to a silicon substrate.

[0037] By setting the peeling force within such a range, the wafer will not be displaced during wafer polishing, and peeling can be easily performed.

[0038] Furthermore, it is preferred that the curable silicone resin composition containing the phenolic antioxidant has a storage modulus at 25° C. of 1,000 Pa or more and 1,000 MPa or less after curing.

[0039] If the curable silicone resin composition has such a storage modulus after curing, the wafer will not shift during wafer polishing and will be stable even when the wafer is subjected to a thermal process.

[0040] Furthermore, it is preferred that a curable silicone resin composition containing the phenolic antioxidant is applied to the wafer to produce a laminate, whereby the peeling interface during peeling of the laminate can be controlled to be the interface between the temporary adhesive layer obtained from the temporary adhesive for wafer processing and the wafer.

[0041] Furthermore, it is preferred that the curable silicone resin composition containing the phenolic antioxidant is applied to the support to produce a laminate, whereby the peeling interface during peeling of the laminate can be controlled to be the interface between the temporary adhesive layer obtained from the temporary adhesive for wafer processing and the support.

[0042] In addition, the present invention provides a method for manufacturing a thin wafer, comprising:

[0043] (a) using any of the above-mentioned temporary adhesives for wafer processing, the circuit-forming surface of a wafer having a circuit-forming surface on one surface and a non-circuit-forming surface on the other side is releasably bonded to a support, thereby forming a wafer stack;

[0044] (b) a step of curing the temporary adhesive;

[0045] (c) grinding or polishing the non-circuit-forming surface of the wafer of the wafer stack;

[0046] (d) a step of processing the non-circuit-forming surface of the wafer; and

[0047] (e) A step of peeling the processed wafer from the support.

[0048] According to such a method for manufacturing a thin wafer, a thin wafer having a through-hole electrode structure or a bump connection structure can be easily manufactured using a temporary adhesive material layer.

[0049] In addition, the present invention provides a wafer stack comprising a support body, a temporary adhesive layer obtained by stacking on the support body any of the above-mentioned temporary adhesives for wafer processing, and a wafer having a circuit-forming surface on the surface and a non-circuit-forming surface on the back, wherein the temporary adhesive layer is adhered to the surface of the wafer in a removable manner.

[0050] If it is such a wafer stack, the peelability of the substrate and the support is stable, especially even when exposed to a high temperature of more than 200°C for a long time after bonding, the substrate can be easily peeled off from the support. Therefore, it can be applied to a wide range of semiconductor film forming processes, and the CVD (chemical vapor deposition) resistance is also excellent. Even for wafers with step differences, a temporary adhesive layer with high film thickness uniformity can be formed, and thin wafers that are easy to break can be easily manufactured. In addition, the temporary adhesive can be selectively bonded to the support, so no residue from the temporary adhesive will remain on the substrate after peeling, and the subsequent cleaning and removal properties are also excellent.

[0051] (3) Beneficial effects

[0052] The temporary adhesive for wafer processing of the present invention can improve the heat resistance of the resin by using a curable silicone resin composition containing an antioxidant. As a result, the peelability of the substrate and the support is stable, and in particular, even when exposed to a high temperature of more than 200°C for a long time after bonding, the substrate can be easily peeled off from the support. Therefore, it can be applied to a wide range of semiconductor film forming processes, and has excellent CVD (chemical vapor deposition) resistance. Even for wafers with step differences, a temporary adhesive layer with high film thickness uniformity can be formed, and thin wafers that are easy to break can be easily manufactured. In addition, the temporary adhesive of the present invention can be selectively bonded to the support, so that no residue from the temporary adhesive will remain on the substrate after peeling, and the subsequent cleaning and removal properties are also excellent. According to the method for manufacturing thin wafers of the present invention, thin wafers with a through-hole electrode structure or a bump connection structure can be easily manufactured. DETAILED DESCRIPTION

[0053] The inventors of the present application conducted intensive research to solve the above-mentioned technical problems and found that a curable silicone resin composition that can be cured by a hydrosilylation reaction of a phenolic antioxidant containing no phosphorus or sulfur atoms can be used as a temporary adhesive, thereby solving the above-mentioned technical problems and completing the present invention.

[0054] That is, the temporary adhesive for wafer processing of the present invention is a temporary adhesive for wafer processing used for temporarily bonding a wafer to a support body, characterized in that the temporary adhesive for wafer processing is composed of a curable silicone resin composition that can be cured by a hydrosilation reaction, and the curable silicone resin composition contains a phenolic antioxidant that does not contain phosphorus atoms and sulfur atoms.

[0055] [Temporary adhesive for wafer processing]

[0056] As described above, the temporary adhesive for wafer processing of the present invention is composed of a curable silicone resin composition containing an antioxidant. From the perspective of applicability to silicon wafers having steps, etc., a silicone resin composition having good spin-coatability is suitable for use as a temporary adhesive for wafer processing.

[0057] Such a curable silicone resin composition preferably contains, for example, the following components (A) to (E). The composition can be cured by heat and / or light using the hydrosilylation reaction catalyst of the component (D).

[0058] (A) 100 parts by mass of an organopolysiloxane having two or more alkenyl groups in one molecule;

[0059] (B) an organohydrogenpolysiloxane containing two or more hydrogen atoms bonded to silicon atoms (SiH groups) in one molecule, wherein the total molar ratio of the SiH groups in the component (B) to the total molar ratio of the alkenyl groups in the component (A) is 0.3 to 10;

[0060] (C) 0.1 to 200 parts by mass of a non-functional organopolysiloxane;

[0061] (D) the phenolic hydrosilylation catalyst, in an amount of 0.1 to 5,000 ppm in terms of metal atomic weight relative to the total mass of components (A), (B), and (C); and

[0062] (E) Antioxidant: 1 to 100,000 ppm based on the total mass of the components (A), (B), and (C).

[0063] [(A) ingredient]

[0064] Component (A) is an organopolysiloxane having two or more alkenyl groups in one molecule. Examples of component (A) include linear or branched diorganopolysiloxanes having two or more alkenyl groups in one molecule, and diorganopolysiloxanes having two or more alkenyl groups in one molecule and having SiO 4 / 2 The invention also provides an organopolysiloxane having a three-dimensional network structure of siloxane units (Q units) represented by siloxane units. Among them, diorganopolysiloxanes or organopolysiloxanes having an alkenyl group content of 0.6 to 9 mol% are preferred. In the present invention, the alkenyl group content refers to the ratio of alkenyl-containing siloxane units to all siloxane units.

[0065] Examples of such organopolysiloxanes include those represented by the following formula (A-1), (A-2), or (A-3).

[0066] [Chemical Formula 1]

[0067]

[0068] In formulas (A-1) to (A-3), R 1 ~R 16 Each independently represents a monovalent hydrocarbon group other than an aliphatic unsaturated hydrocarbon group. 1 ~X 5 Each is independently an alkenyl-containing monovalent organic group.

[0069] In formula (A-1), a and b are each independently an integer of 0 to 3. In formula (A-1) and (A-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 Integer ≤ 100. Where a+b+c 1 ≥2. a, b, c 1 、c 2 d 1 and d 2 A combination of numbers such that the alkenyl group content is 0.6 to 9 mol % is preferred.

[0070] In formula (A-3), e is an integer from 1 to 3. 1 、f 2 and f 3 In order to make (f 2 +f 3 ) / f 1 is 0.3~3.0 and f 3 / (f 1 +f 2 +f 3 ) is a number between 0.01 and 0.6.

[0071] As the monovalent hydrocarbon group other than the aliphatic unsaturated hydrocarbon group, a hydrocarbon group having 1 to 10 carbon atoms is preferred, and examples thereof 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 them, alkyl groups such as methyl or phenyl are preferred.

[0072] As the alkenyl group-containing monovalent organic group, preferable are organic groups having 2 to 10 carbon atoms, and examples thereof include vinyl group, allyl group, hexenyl group, octenyl group, and the like; acrylpropyl group, acrylmethyl group, methacrylpropyl group, and the like (meth)acrylalkyl group; acryloxypropyl group, acryloxymethyl group, methacryloxypropyl group, methacryloxy methyl group, and the like (meth)acryloxyalkyl group; cyclohexenylethyl group, vinyloxypropyl group, and the like alkenyl group-containing monovalent hydrocarbon group. Of these, from an industrial viewpoint, vinyl group is preferable.

[0073] In formula (A-1), a and b are each independently an integer of 0 to 3, and if a is 1 to 3, the molecular chain terminal is capped with an alkenyl group, and thus the reaction can be completed in a short time by the molecular chain terminal alkenyl group having a high reactivity, and thus it is preferable. Further, from a cost aspect, it is industrially preferable that a be 1. The alkenyl group-containing diorganopolysiloxane represented by formula (A-1) or (A-2) is preferably in an oil or raw rubber state.

[0074] The organopolysiloxane represented by formula (A-3) contains SiO 4 / 2 units and has a three-dimensional network structure. In formula (A-3), e is each independently an integer of 1 to 3, and from a cost aspect, it is industrially preferable that e be 1. Further, the average value of e and f 3 / (f 1 + f 2 + f 3 ) is preferably 0.02 to 1.5, and more preferably 0.03 to 1.0. The organopolysiloxane represented by formula (A-3) can be used in the form of a solution dissolved in an organic solvent.

[0075] The number average molecular weight (Mn) of the organopolysiloxane of the (A) component is preferably 100 to 1,000,000, and more preferably 1,000 to 100,000. If Mn is in the range, it is preferable from the viewpoint of the operability accompanying the viscosity of the composition or the processability accompanying the storage modulus after curing. In addition, in the present application, Mn is a polystyrene conversion measurement value obtained using gel permeation chromatography (GPC) with toluene as a solvent.

[0076] The (A) component can be used singly with one kind, or two or more kinds in combination. It is particularly preferable to use the organopolysiloxane represented by formula (A-1) in combination with the organopolysiloxane represented by formula (A-3). At this time, the use amount of the organopolysiloxane represented by formula (A-3) is preferably 1 to 1,000 parts by mass, and more preferably 10 to 500 parts by mass, relative to 100 parts by mass of the organopolysiloxane represented by formula (A-1).

[0077] [(B) component]

[0078] Component (B) is a crosslinking agent, which is an organohydrogenpolysiloxane having at least two, and preferably three or more, hydrogen atoms (SiH groups) bonded to silicon atoms in one molecule. The organohydrogenpolysiloxane may be linear, branched, or cyclic. These organohydrogenpolysiloxanes may be used alone or in combination of two or more.

[0079] The viscosity of the organohydrogenpolysiloxane of the component (B) at 25° C. is preferably 1 to 5,000 mPa·s, more preferably 5 to 500 mPa·s. In the present invention, the viscosity is a value measured at 25° C. using a rotational viscometer.

[0080] The organohydrogenpolysiloxane of component (B) preferably has an Mn of 100 to 100,000, more preferably 500 to 10,000. The Mn within the above range is preferred from the perspective of workability due to the viscosity of the composition and processability due to the storage modulus after curing.

[0081] The mode that makes the total of the SiH group in (B) composition relative to the total of the alkenyl in (A) composition is preferably 0.3~10 scope, more preferably 0.3~5.0 scope, further preferably 0.5~3.0 scope is blended (B) composition in mol ratio (SiH group / alkenyl).If described mol ratio is more than 0.3, then temporary adhesive layer fully solidifies and cross-linking density can not tail off yet.In addition, if described mol ratio is below 10, then cross-linking density can not be made to become too high, can obtain sufficient adhesion and viscosity, can prolong the usable time of treatment fluid.

[0082] [(C) ingredient]

[0083] Component (C) is a non-functional organopolysiloxane. "Non-functional" here means that the molecule does not contain reactive groups such as hydrogen atoms, halogen atoms, hydroxyl groups, and alkoxy groups that are directly bonded to silicon atoms, and does not contain reactive groups such as alkenyl groups and epoxy groups that are directly bonded to silicon atoms or bonded to silicon atoms via any group.

[0084] Examples of such nonfunctional organopolysiloxanes include those having unsubstituted or substituted monovalent hydrocarbon groups having 1 to 12, preferably 1 to 10, carbon atoms other than aliphatic unsaturated hydrocarbon groups. Examples of such monovalent hydrocarbon groups include alkyl groups such as methyl, ethyl, propyl, butyl, pentyl, hexyl, and heptyl; cycloalkyl groups such as cyclohexyl; aryl groups such as phenyl, tolyl, xylyl, and naphthyl; and aralkyl groups such as benzyl and phenethyl. Furthermore, some or all of the hydrogen atoms in these groups may be substituted with halogen atoms such as chlorine, fluorine, or bromine. Examples of such groups include haloalkyl groups such as chloromethyl, 3-chloropropyl, and 3,3,3-trifluoropropyl. These monovalent hydrocarbon groups are preferably alkyl groups and aryl groups, with methyl and phenyl groups being more preferred.

[0085] The molecular structure of the non-functional organopolysiloxane of component (C) is not particularly limited and may be any of linear, branched, cyclic, etc., but is preferably a linear or branched organopolysiloxane, and preferably a linear diorganopolysiloxane whose main chain is essentially composed of repeating diorganosiloxane units and whose molecular chain ends are capped with triorganosiloxy groups.

[0086] From the perspectives of the composition's workability, substrate coating properties, mechanical properties of the cured product, and support releasability, the viscosity (25°C) of a 30% by mass toluene solution of the non-functional organopolysiloxane (component (C)) is preferably 100 to 500,000 mPa·s, and more preferably 200 to 100,000 mPa·s. This range provides an appropriate molecular weight, thus preventing volatilization during heat curing of the silicone resin composition, which could hinder the effectiveness of the composition, or wafer cracking during wafer thermal processes such as CVD. Furthermore, it is preferred for its excellent workability and coating properties.

[0087] Examples of the non-functional organopolysiloxane include dimethylsiloxane polymers terminated with trimethylsiloxy groups at both ends of the molecular chain, phenylmethylpolysiloxane terminated with trimethylsiloxy groups at both ends of the molecular chain, 3,3,3-trifluoropropylmethylsiloxane polymers terminated with trimethylsiloxy groups at both ends of the molecular chain, dimethylsiloxane-methylphenylsiloxane copolymers terminated with trimethylsiloxy groups at both ends of the molecular chain, dimethylsiloxane-3,3,3-trifluoropropylmethyl copolymers terminated with trimethylsiloxy groups at both ends of the molecular chain, and methylphenylsiloxane copolymers terminated with trimethylsiloxy groups at both ends of the molecular chain. Trimethylsiloxy-terminated methylphenylsiloxane-3,3,3-trifluoropropyl methyl copolymer at both ends of the molecular chain, trimethylsiloxy-terminated dimethylsiloxane-3,3,3-trifluoropropyl methylsiloxane-methylphenylsiloxane copolymer at both ends of the molecular chain, dimethylphenylsiloxy-terminated dimethylpolysiloxane at both ends of the molecular chain, dimethylphenylsiloxy-terminated methylphenylpolysiloxane at both ends of the molecular chain, dimethylphenylsiloxy-terminated dimethylsiloxane-methylphenylsiloxane copolymer at both ends of the molecular chain, etc.

[0088] (C) Component (C) is a non-functional organopolysiloxane. One kind of non-functional organopolysiloxane can be used alone, or two or more kinds of non-functional organopolysiloxane can be used in combination. In addition, the non-functional organopolysiloxane is preferably in the form of an oil or a raw rubber.

[0089] The (C) component is preferably blended at 0.1 to 200 parts by mass, and further preferably blended at 1 to 100 parts by mass, relative to 100 parts by mass of the (A) component. If the blending ratio is 0.1 parts by mass or more, peeling can be easily performed, particularly in the process of peeling the support from the substrate, and thus it is preferable. In addition, if the blending ratio is 200 parts by mass or less, the wafer does not peel during wafer backgrinding or wafer processing such as heat treatment thereafter, and wafer processing durability can be obtained, and thus it is preferable.

[0090] [(D) Component]

[0091] The (D) component is a hydrosilylation reaction catalyst, and is preferably a platinum group metal-based hydrosilylation reaction catalyst. The (D) component is a catalyst that promotes the addition reaction of the alkenyl group in the (A) component and the hydrogenosilane group in the (B) component. There are a thermally active hydrosilylation reaction catalyst (D-1) that is activated by heat, and a photoactive hydrosilylation reaction catalyst (D-2) that is activated by light. Both of these hydrosilylation reaction catalysts are generally compounds of noble metals, and since they are expensive, platinum or platinum compounds, which are relatively easy to obtain, are often used.

[0092] (D-1) Thermally active hydrosilylation reaction catalyst

[0093] As the platinum compound, for example, chloroplatinic acid or a complex of chloroplatinic acid with an olefin such as ethylene, a complex with an alcohol or a vinylsiloxane, a platinum metal supported on silica, alumina, carbon, or the like can be given. As a platinum group metal catalyst other than a platinum compound, rhodium, ruthenium, iridium, and palladium compounds are also known, and for example, RhCl(PPh3)3, RhCl(CO)(PPh3)2, Ru3(CO) 12 , IrCl(CO)(PPh3)2, Pd(PPh3)4, and the like can be given. In the formula, Ph is a phenyl group.

[0094] (D-2) Photoactive hydrosilylation reaction catalyst

[0095] The photoactive hydrosilylation reaction catalyst is a catalyst that is activated by irradiation of light, particularly ultraviolet rays having a wavelength of 300 to 400 nm, and promotes the addition reaction of the alkenyl group in the (A) component and the Si-H group in the (B) component. The promotion effect has a temperature dependence, and a high promotion effect can be obtained at a higher temperature. Therefore, it is preferable to use at an ambient temperature of 0 to 200°C, and more preferably 10 to 100°C, after light irradiation, from the viewpoint of completing the reaction within an appropriate reaction time.

[0096] The ligand of this catalyst preferably exhibits catalytic activity under UV light of medium to long wavelengths, such as UV-B and UV-A, to suppress damage to the wafer. Examples of such ligands include cyclic diene ligands and β-diketone ligands.

[0097] In summary, as preferred examples of photoactive hydrosilylation catalysts, as cyclic diene ligand type, for example (η 5 -cyclopentadienyl)tri(σ-alkyl)platinum(IV) complexes, particularly specifically (methylcyclopentadienyl)trimethylplatinum(IV), (cyclopentadienyl)trimethylplatinum(IV), (1,2,3,4,5-pentamethylcyclopentadienyl)trimethylplatinum(IV), (cyclopentadienyl)dimethylethylplatinum(IV), (cyclopentadienyl)dimethylacetylplatinum(IV), (trimethylsilylcyclopentadienyl)trimethylplatinum(IV), (methoxycarbonylcyclopentadienyl)trimethylplatinum(IV), (dimethylphenylsilylcyclopentadienyl)trimethylplatinum(IV), etc., and β-diketone complexes are also mentioned. The body type includes β-diketone platinum (II) or platinum (IV) complexes, and more specifically, trimethyl (acetylacetonate) platinum (IV), trimethyl (3,5-heptanedione) platinum (IV), trimethyl (methylacetoacetate) platinum (IV), bis (2,4-pentanedione) platinum (II), bis (2,4-hexanedione) platinum (II), bis (2,4-heptanedione) platinum (II), bis (3,5-heptanedione) platinum (II), bis (1-phenyl-1,3-butanedione) platinum (II), bis (1,3-diphenyl-1,3-propanedione) platinum (II), bis (hexafluoroacetylacetone) platinum (II), etc.

[0098] When using these catalysts, if they are solid catalysts, they can be used in solid form. However, in order to obtain a more uniform cured product, it is preferred to use the catalyst dissolved in a suitable solvent. The suitable solvent herein refers to a solvent that is soluble in any one or all of components (A), (B), and (C) and is suitable for the working environment and process.

[0099] The amount of component (D) added is an effective amount, typically 0.1 to 5,000 ppm, preferably 1 to 1,000 ppm, relative to the combined mass of components (A), (B), and (C), calculated as metal atomic weight. A content of 0.1 ppm or greater prevents a decrease in the curability of the composition, a reduction in crosslink density, and a decrease in holding power. A content of 5,000 ppm or less suppresses side reactions such as dehydrogenation during curing, extending the usable life of the treatment solution.

[0100] [(E) ingredient]

[0101] Component (E) is a phenolic antioxidant. To avoid inhibiting the hydrosilylation reaction, it is preferred that the chemical formula contain no phosphorus or sulfur atoms. Therefore, in the present invention, the curable silicone resin composition must contain a phenolic antioxidant that does not contain phosphorus or sulfur atoms.

[0102] Preferred examples of such antioxidants include 4,4'-dihydroxy-3,3',5,5'-tetraisopropylbiphenyl, 3-(3,5-di-tert-butyl-4-hydroxyphenyl)-N'-[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl]propanehydrazide, 4,6-di-tert-butylbenzene-1,3-diol, bis[3-[3-(tert-butyl)-4-hydroxy-5-methylphenyl]propionate] 2,4,8,10-tetraoxaspiro[5.5]undecane-3,9-diylbis(2-methylpropane-2,1-diyl), 2,2'-methylenebis[6-(1-methylcyclohexyl)-p-cresol], 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl]propanehydrazide, ) octadecyl propionate, triethylene glycol bis[3-(3-tert-butyl-4-hydroxy-5-methylphenyl) propionate], 2,4,6-tris(2,4-dihydroxyphenyl)-1,3,5-triazine, 2,6-di-tert-butyl-4-ethylphenol, 2,2'-methylenebis(6-tert-butyl-4-ethylphenol), 2,6-di-tert-butyl-4-methoxyphenol, 4,4'-butylenebis(6-tert-butyl-m-cresol), 6-tert-butyl-2,4-xylenol, 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid, 2,6-di-tert-butylphenol, 4,4'-dihydroxy-3,3',5,5'-tetraisopropylbiphenyl, 2,5-bis(1,1,3,3-tetramethyl 2,5-di-tert-butylhydroquinone, 2,6-di-tert-butyl-p-cresol, 2,6-di-tert-butyl-4-methoxyphenol, 2,2'-methylenebis(6-cyclohexyl-p-cresol), 4-(hexyloxy)-2,3,6-trimethylphenol, 3,5-di-tert-butyl-4-hydroxybenzoate, 2,2',6,6'-tetra-tert-butyl-4,4'-dihydroxybiphenyl, 2,4,6-tris(2,4-dihydroxyphenyl)-1, 3,5-triazine, 2,5-di-tert-butylhydroquinone, 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, ethylenebis(oxyethylene)bis-(3-(5-tert-butyl-4-hydroxy-m-tolyl)propionate), etc., among which, 4,4'-dihydroxy-3,3',5,5'-tetraisopropylbiphenyl, 3-(3,5-di-tert-butyl-4-hydroxyphenyl)-N'-[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl]propane hydrazide, bis[3-[3-(tert-butyl)-4-hydroxy-5-methylphenyl]propionic acid] 2,4,8,10-tetraoxaspiro[5.5] Undecane-3,9-diylbis(2-methylpropane-2,1-diyl), 2,2'-methylenebis[6-(1-methylcyclohexyl)-p-cresol], 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid octadecyl, triethylene glycol bis[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionic acid ester], 2,6-di-tert-butyl-4-ethylphenol, 2,2'-methylenebis(6-tert-butyl-4 -ethylphenol), 2,6-di-tert-butyl-4-methoxyphenol, 6-tert-butyl-2,4-dimethylphenol, 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid, 2,6-di-tert-butylphenol, 4,4'-dihydroxy-3,3',5,5'-tetraisopropylbiphenyl, N,N'-(hexane-1,6-diyl)bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propaneamide], pentaerythritol tetra[ 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate], 2,6-di-tert-butyl-p-cresol, 2,6-di-tert-butyl-4-methoxyphenol, 2,2'-methylenebis(6-cyclohexyl-p-cresol), 4-(hexyloxy)-2,3,6-trimethylphenol, 3,5-di-tert-butyl-4-hydroxybenzoate, 2,2',6,6'-tetra-tert-butyl-4,4'-dihydroxybiphenyl, 2,4, Hindered phenolic antioxidants such as 6-tris(2,4-dihydroxyphenyl)-1,3,5-triazine, 2,5-di-tert-butylhydroquinone, 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, and ethylenebis(oxyethylene)bis-(3-(5-tert-butyl-4-hydroxy-m-tolyl)propionate) are preferred because they are more likely to produce an antioxidant effect.

[0103] When using these antioxidants, if they are solid, they can be used in a solid state. However, in order to obtain a more uniform solidified product, they are preferably dissolved in a suitable solvent before use.

[0104] The amount of component (E) added is an effective amount, typically 1 to 100,000 ppm, preferably 10 to 10,000 ppm, relative to the total mass of components (A), (B), and (C). A concentration of 1 ppm or greater can improve the heat resistance stability of the cured product, while a concentration of 100,000 ppm or less can improve heat resistance stability without affecting curability or post-cured physical properties.

[0105] [(F)INGREDIENT]

[0106] The curable silicone resin composition may further contain a reaction control agent (hydrosilylation reaction control agent) as component (F). The reaction control agent is optionally added as needed to prevent the composition from becoming thicker or gelling during preparation of the composition or coating on a substrate.

[0107] Examples of the reaction control agent include 3-methyl-1-butyn-3-ol, 3-methyl-1-pentyn-3-ol, 3,5-dimethyl-1-hexyn-3-ol, 1-ethynylcyclohexanol, 3-methyl-3-trimethylsiloxy-1-butyn, 3-methyl-3-trimethylsiloxy-1-pentyn, 3,5-dimethyl-3-trimethylsiloxy-1-hexyn, 1-ethynyl-1-trimethylsiloxycyclohexane, bis(2,2-dimethyl-3-butynyloxy)dimethylsilane, 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane, and 1,1,3,3-tetramethyl-1,3-divinyldisiloxane. Among these, 1-ethynylcyclohexanol and 3-methyl-1-butyn-3-ol are preferred.

[0108] When the curable silicone resin composition includes component (F), the controllability varies depending on the chemical structure, and its content should be adjusted to the optimal amount. Considering the effects on curability, storage stability, and physical properties after curing, its content is preferably 0.001 to 10 parts by mass, more preferably 0.01 to 10 parts by mass, relative to the total mass of components (A), (B), and (C). When the content of component (F) is within this range, the composition has a long usable life, achieves long-term storage stability, and exhibits excellent curability and handleability.

[0109] The curable silicone composition may further contain R A 3SiO 0.5 Unit (where R A Each independently represents an unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms. ) and SiO2 units and R A 3SiO 0.5 The molar ratio of the unit to the SiO2 unit (R A 3SiO 0.5 The amount of the organopolysiloxane added is preferably 0 to 500 parts by mass relative to 100 parts by mass of the component (A).

[0110] In order to further improve the physical strength of the temporary adhesive layer obtained from the curable silicone resin composition, a filler such as silica may be added to the curable silicone resin composition.

[0111] To improve workability due to the low viscosity of the composition, improve miscibility, and adjust the thickness of the temporary adhesive layer, the curable silicone resin composition can be dissolved by adding a solvent. The solvent used is not particularly limited as long as it can dissolve the components. For example, hydrocarbon solvents such as pentane, hexane, cyclohexane, isooctane, nonane, decane, p-menthane, pinene, isododecane, and limonene are preferred.

[0112] Examples of solubilization methods include: preparing the curable silicone resin composition and then adding a solvent to adjust the desired viscosity; and pre-diluting the high-viscosity components (A), (B), and / or (C) with a solvent to improve workability or mixing, and then mixing the remaining components. Furthermore, the solubilization mixing method can be selected based on the viscosity and workability of the composition, using a shaker, magnetic stirrer, or various mixers.

[0113] The amount of solvent added may be appropriately set from the perspective of adjusting the viscosity or workability of the composition, the thickness of the temporary adhesive layer, etc. For example, the amount of solvent added is preferably 5 to 900 parts by mass, more preferably 10 to 400 parts by mass, relative to 100 parts by mass of the curable silicone resin composition.

[0114] The temporary adhesive layer can be formed by coating the curable silicone resin composition on the substrate by spin coating, roller coating, etc. When the temporary adhesive layer is formed on the substrate by spin coating, the curable silicone resin composition is preferably dissolved and then coated.

[0115] From the viewpoint of coating properties, the viscosity of the solubilized curable silicone resin composition at 25° C. is preferably 1 to 100,000 mPa·s, more preferably 10 to 10,000 mPa·s.

[0116] The 180° peel force of a 25 mm wide test piece (e.g., a glass test piece) at 25°C after curing the curable silicone resin composition relative to a silicon substrate is typically 2 to 100 gf, preferably 3 to 50 gf, and more preferably 5 to 30 gf. A value of 2 gf or greater prevents wafer shifting during polishing, while a value of 100 gf or less facilitates wafer peeling.

[0117] The storage modulus of the curable silicone resin composition at 25°C after curing is 1,000 Pa to 1,000 MPa, preferably 10,000 Pa to 100 MPa. A storage modulus of 1,000 Pa or higher provides a strong film, preventing wafer shifting or wafer cracking associated with shifting during wafer polishing. A storage modulus of 1,000 MPa or lower mitigates deformation stress during wafer thermal processes such as CVD, ensuring stability during wafer thermal processing.

[0118] When the laminated body of wafer (substrate) / temporary adhesive layer / support is formed by curable silicone resin composition, by being coated on wafer (substrate) side or being coated on support side, can after forming laminated body, selectively control the interface when peeling off.That is, be coated on wafer (substrate), when forming support and joint body and peeling off, selectively peel off between wafer (substrate) / temporary adhesive layer, now, temporary adhesive layer remains in support body as residue, therefore can simplify subsequent wafer (substrate) cleaning process, from the perspective of improving operability and preferred.On the other hand, the object of coating curable silicone resin composition is changed to support body, when peeling off the joint body with wafer (substrate), selectively peel off at temporary adhesive layer / support interface.Now, the residue of temporary adhesive layer remains in wafer (substrate) side, therefore may cause operability to decline in subsequent wafer (substrate) cleaning process. However, when applied to the support side, it is preferred from the viewpoint of being less susceptible to the influence of, for example, curing inhibition of the hydrosilylation reaction due to the wafer (substrate) used, and being able to easily obtain a stable function as a temporary adhesive.

[0119] [Thin wafer manufacturing method]

[0120] The method for producing a thin wafer of the present invention is characterized in that the temporary adhesive for wafer processing is used for temporarily bonding a wafer having a semiconductor circuit or the like to a support.

[0121] The method for manufacturing a thin wafer of the present invention includes the following steps (a) to (e).

[0122] [Step (a)]

[0123] Step (a) is a temporary bonding step of releasably bonding the circuit-forming surface of a wafer having a circuit-forming surface on its front surface and a non-circuit-forming surface on its back surface to a support using the temporary adhesive for wafer processing to form a wafer stack.

[0124] Specifically, any one of the following methods is suitable: a method of using the temporary adhesive for wafer processing to form a temporary adhesive layer on the surface of the wafer, and bonding the support body to the surface of the wafer via the temporary adhesive layer; a method of using the temporary adhesive for wafer processing to form a temporary adhesive layer on the surface of the support body, and bonding the support body to the surface of the wafer via the temporary adhesive layer; a method of using the temporary adhesive for wafer processing to form a temporary adhesive layer on both the surface of the wafer and the surface of the support body, and bonding the support body to the surface of the wafer via the temporary adhesive layer.

[0125] Wafers applicable to the present invention are typically semiconductor wafers. Examples of such semiconductor wafers include not only silicon wafers but also germanium wafers, gallium-arsenic wafers, gallium-phosphorus wafers, and gallium-arsenic-aluminum wafers. The thickness of the wafer is not particularly limited, but is typically 600-800 μm, more typically 625-775 μm.

[0126] As the support, substrates such as silicon wafers, glass plates, and quartz wafers can be used, but are not limited thereto. In the present invention, when the curable silicone resin composition is cured without irradiating the support with light, the support does not need to be light-transmissive. On the other hand, when the curable silicone resin composition is cured by irradiating the support with light, a light-transmissive support is preferably used.

[0127] The temporary adhesive layer can be formed by molding the curable silicone resin composition into a film and laminating it on a wafer or support, or by applying the curable silicone resin composition using methods such as spin coating or roller coating. When the curable silicone resin composition is a solution containing a solvent, after application, it is preferably pre-baked at a temperature of 40-200°C, more preferably 50-150°C, depending on the volatilization conditions of the solvent, before use.

[0128] The temporary adhesive layer is preferably formed to a thickness of 0.1 to 500 μm, preferably 1.0 to 200 μm. A thickness of 0.1 μm or greater allows for full coverage of the substrate without leaving any unapplied areas. On the other hand, a thickness of 500 μm or less allows for the durability of the polishing process used to create thin wafers.

[0129] Examples of a method for bonding the support body and the surface of the wafer via the temporary adhesive layer include a method of uniformly pressing the support body at a temperature range of preferably 10 to 200° C., more preferably 20 to 150° C., under reduced pressure.

[0130] The pressure when the wafer and the support body that have formed the temporary adhesive layer are pressed together depends on the viscosity of the temporary adhesive layer, and is preferably 0.01 to 10 MPa, more preferably 0.1 to 1.0 MPa. If the pressure is more than 0.01 MPa, the circuit forming surface or the space between the wafer and the support body can be filled with the temporary adhesive layer. If it is below 10 MPa, it will not cause wafer cracking, deterioration of the flatness of the wafer and the temporary adhesive layer, and subsequent wafer processing is good.

[0131] The wafers can be bonded using a commercially available wafer bonder, such as EVG520IS and 850TB from EVG, or XBS300 from SUSSMicroTec.

[0132] [Step (b)]

[0133] Step (b) is a step of curing the temporary adhesive layer. In the case of a curable silicone resin composition, after forming the wafer stack, the temporary adhesive layer is cured by heating the wafer stack at preferably 50-300°C, more preferably 100-200°C, for preferably 1 minute to 4 hours, more preferably 5 minutes to 2 hours.

[0134] In the case of a photocurable resin composition, after forming the above-mentioned laminate substrate, the temporary adhesive layer can be photocured by irradiating light from the support body side with light transmittance, or after forming the above-mentioned laminate substrate with a photocurable silicone resin composition that has been previously irradiated with light, it can be cured. The type of active light at this time is not particularly limited, preferably ultraviolet rays, and more preferably ultraviolet rays with a wavelength of 300-400nm. For ultraviolet irradiation (illuminance), in order to obtain good curability, it is expected to be 100mJ / cm3 in terms of cumulative light intensity. 2 ~100,000mJ / cm 2 , preferably 500mJ / cm 2 ~10,000mJ / cm 2 , more preferably 1,000~5,000mJ / cm 2 If the ultraviolet irradiation amount (illuminance) is above the lower limit of the above range, energy sufficient to activate the photoactive hydrosilylation reaction catalyst in the temporary adhesive layer can be obtained, and a sufficient cured product can be obtained. On the other hand, if the ultraviolet irradiation amount (illuminance) is below the upper limit of the above range, sufficient energy can be irradiated to the composition, and a sufficient cured product can be obtained without causing decomposition of components in the polymer layer or partial deactivation of the catalyst.

[0135] Ultraviolet irradiation can be light with multiple luminescence spectra or light with a single luminescence spectrum. In addition, a single luminescence spectrum can have a wide spectrum in the region of 300nm to 400nm. The light with a single luminescence spectrum is light with a peak (i.e., maximum peak wavelength) in the range of 300nm to 400nm, preferably 350nm to 380nm. As the light source for irradiating such light, ultraviolet light emitting semiconductor element light sources such as ultraviolet light emitting diodes (UV LEDs) and ultraviolet light emitting semiconductor lasers can be listed.

[0136] As light sources for irradiating light having multiple emission spectra, there can be listed metal halide lamps, xenon lamps, carbon arc lamps, chemical lamps, sodium lamps, low-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, etc., gas lasers such as nitrogen, liquid lasers of organic pigment solutions, solid lasers containing rare earth ions in inorganic single crystals, etc.

[0137] When the light has a peak in a wavelength region shorter than 300nm in the luminescence spectrum, or when there is a wavelength with a radiant illuminance greater than 5% of the radiant illuminance of the maximum peak wavelength in the luminescence spectrum in a wavelength region shorter than 300nm (for example, when the luminescence spectrum is broad in a wide-area wavelength region), and when a substrate having light transmittance even for wavelengths shorter than 300nm is used on a support such as a quartz wafer, in order to obtain sufficient cured product, it is preferred to utilize an optical filter to remove the wavelength except for the light in the wavelength region shorter than 300nm. Thus, the radiant illuminance of each wavelength in the wavelength region shorter than 300nm is made to be less than 5% of the radiant illuminance of the maximum peak wavelength, preferably less than 1%, more preferably less than 0.1%, and further preferably 0%. In addition, in the luminescence spectrum, when there are multiple peaks in the wavelength region of 300nm to 400nm, the peak wavelength showing the maximum absorbance is set to the maximum peak wavelength. The optical filter is not particularly limited as long as it cuts off wavelengths shorter than 300 nm, and a known optical filter can be used. For example, a 365 nm bandpass filter can be used. Furthermore, the illuminance and spectral distribution of ultraviolet light can be measured using a spectroradiometer, such as the USR-45D (Ushio Inc.).

[0138] The light irradiation device is not particularly limited, and for example, a point irradiation device, a surface irradiation device, a line irradiation device, a conveyor irradiation device, or the like can be used.

[0139] When curing a photocurable silicone resin composition, the light irradiation time also depends on the illumination intensity and cannot be generalized. For example, if the illumination intensity is adjusted to 1 to 300 seconds, preferably 10 to 200 seconds, and more preferably 30 to 150 seconds, the irradiation time can be appropriately shortened, without any particular operational issues. Furthermore, the photocurable silicone resin composition that has been irradiated with light will gel after 1 to 120 minutes, particularly 5 to 60 minutes. In the present invention, gelation refers to a state in which the curing reaction of the photocurable silicone resin composition has partially progressed, resulting in the composition losing its fluidity.

[0140] Furthermore, since the curing rate of the photocurable silicone resin composition after light irradiation depends on the ambient temperature, the wafer processing product (laminated substrate) is preferably left at 20-150°C, more preferably 30-100°C, from the viewpoint of improving workability.

[0141] Thus, a wafer stack can be obtained, which comprises a support body, a temporary adhesive layer obtained from a temporary adhesive for wafer processing stacked on the support body, and a wafer having a circuit-forming surface on the front surface and a non-circuit-forming surface on the back surface, wherein the temporary adhesive layer is adhered to the surface of the wafer in a removable manner.

[0142] [Step (c)]

[0143] Process (c) is a process for grinding or polishing the non-circuit forming surface of the wafer (i.e., the wafer of the wafer stack) temporarily bonded to the support, that is, grinding the back side of the wafer of the wafer stack obtained in the process to reduce the thickness of the wafer. There is no particular restriction on the grinding method of the back side of the wafer, and a known grinding method can be used. It is preferred to grind while adding water to the wafer and the grindstone (diamond, etc.) to cool it. As a device for grinding the back side of the wafer, for example, DAG-810 (trade name) manufactured by DISCO CORPORATION can be listed. In addition, chemical mechanical polishing (CMP) can also be performed on the back side of the wafer.

[0144] [Step (d)]

[0145] Process (d) is a process for processing the non-circuit forming surface of the wafer laminated body that has been ground in process (c). That is, it is a process for processing the non-circuit forming surface of the wafer laminated body after thinning by back grinding. This process includes various processes used at the wafer level. As examples, electrode formation, metal wiring formation, protective film formation, etc. can be listed. More specifically, metal sputtering for forming electrodes, wet etching for etching metal sputtering layers, coating of resist for making masks for forming metal wiring, patterning by exposure and development, stripping of resist, dry etching, formation of metal plating, silicon etching for forming TSV, formation of oxide film on silicon surface, etc., can be listed.

[0146] [Step (e)]

[0147] Process (e) is a process of peeling the wafer processed in process (d) from the support, that is, after various processes are performed on the thinned wafer, the wafer is peeled from the support before cutting. As this peeling process, it is usually carried out under relatively mild conditions of room temperature to about 60°C. As peeling methods, there can be listed: a method of fixing one of the wafer or the support of the wafer stack horizontally, applying a certain angle to the other and lifting it from the horizontal direction; a method of sticking a protective film on the polished surface of the polished wafer, and peeling the wafer and the protective film from the wafer stack by tearing, etc. When the peeling process is carried out using these peeling methods, it is usually carried out at room temperature.

[0148] Furthermore, step (e) preferably comprises:

[0149] (e1) a step of attaching a dicing tape to the wafer surface of the processed wafer,

[0150] (e2) vacuum adsorption of the dicing tape surface onto the adsorption surface, and

[0151] (e3) a process of peeling the support from the wafer on which the process has been performed by peel-off at a temperature of the adsorption surface in the range of 10°C to 100°C.

[0152] Thus, the support can be easily peeled from the wafer on which the process has been performed, and furthermore, the subsequent cutting process can be easily performed.

[0153] Furthermore, a process (f) of removing the temporary adhesive layer remaining on the circuit formation surface of the wafer on which the peeling has been performed is preferably performed after the process (e). A part of the temporary adhesive layer can remain on the circuit formation surface of the wafer peeled from the support by the process (e), and this temporary adhesive layer can be removed, for example, by washing the wafer.

[0154] In the process (f), any washing liquid that can dissolve the silicone resin of the temporary adhesive layer can be used, and specifically, pentane, hexane, cyclohexane, decane, isononane, p-menthane, pinene, isododecane, limonene, and the like can be listed. These solvents can be used singly or in combination of two or more.

[0155] Furthermore, when it is difficult to remove the temporary adhesive layer, an alkali or an acid can be added to the washing liquid. As the alkali, amine such as ethanolamine, diethanolamine, triethanolamine, triethylamine, ammonia, and the like; and ammonium salt such as tetramethylammonium hydroxide can be used. As the acid, organic acid such as acetic acid, oxalic acid, benzene sulfonic acid, dodecylbenzenesulfonic acid, and the like can be used. The alkali or the acid is added in an amount such that the concentration in the washing liquid is preferably 0.01 to 10 mass%, and more preferably 0.1 to 5 mass%. Furthermore, in order to improve the removability of the residue, an existing surfactant can be added. Furthermore, SPIS-TA-CLEANER series (manufactured by Shin-Etsu Chemical Co., Ltd.) that can be obtained as a wafer cleaning agent is also suitably used.

[0156] As the method of washing the wafer, a method of washing with a paddle using the washing liquid, a method of washing with a spray, and a method of immersing in a tank of the washing liquid can be listed. The temperature at the time of washing is preferably 10 to 80°C, and more preferably 15 to 65°C, and if necessary, the temporary adhesive layer can be dissolved using these washing liquids, and then finally washed with water or alcohol, and subjected to a drying process.

[0157] The thickness of the thin wafer obtained by the manufacturing method of the present application is typically 5 to 300 μm, and more typically 10 to 100 μm.

[0158] Example

[0159] The present application will be described more specifically below by way of Production Examples, Comparative Production Examples, Examples and Comparative Examples, but the present application is not limited to these Examples. In addition, the viscosity is a measured value at 25°C obtained by a rotational viscometer.

[0160] [1] Preparation of curable silicone resin solution

[0161] [Production Example 1]

[0162] To a solution formed of 100 parts by mass of dimethylpolysiloxane having Mn of 3 million (consisting of (CH3)2SiO 2 / 2 units (D units) 97.5 mole%, (CH2=CH)(CH3)SiO 2 / 2 units (D Vi units) 2.5 mole%) and 200 parts by mass of toluene, was added a solution formed of 50 parts by mass of vinylmethylpolysiloxane having a resin structure with Mn of 7,000 (consisting of SiO 4 / 2 units (Q units) 50 mole%, (CH3)3SiO 1 / 2 units (M units) 48 mole% and (CH2=CH)(CH3)2SiO 1 / 2 units (M Vi units) 2 mole%) and 100 parts by mass of toluene, a solution of 21 parts by mass of organohydrogenpolysiloxane having Mn of 2,400 (consisting of (CH3)2SiO 2 / 2 units (D units) 83.9 mole%, (CH3)HSiO 2 / 2 units (D H units) 16.1 mole%) and 50 parts by mass of dimethylpolysiloxane terminated at both molecular chain ends by trimethylsiloxy groups having a viscosity (25°C) of 30,000 mPa-s in a 30% toluene solution, and 120 parts by mass of toluene, a solution of 0.6 parts by mass of 1-ethynylcyclohexanol, and 0.1 parts by mass of an antioxidant represented by the following formula (M-1) and 0.4 parts by mass of toluene, were mixed. Then, 0.4 parts by mass of a hydrosilation catalyst CAT-PL-5 (manufactured by Shin-Etsu Chemical Co., Ltd., platinum concentration 1.0 mass%) was added thereto, and filtered with a 0.2 μm membrane filter, thereby preparing a thermosetting silicone resin solution Al. The viscosity of the resin solution (Al) at 25°C was 2,300 mPa-s.

[0163] The value of the total of SiH groups in the (B) component relative to the total of alkenyl groups in the (A) component (Si-H / Si-Vi) in this Production Example 1 can be calculated from the following formula.

[0164] The value of (Si-H / Si-Vi), which is the total amount of SiH groups in the component (B) relative to the total amount of alkenyl groups in the component (A) in Preparation Example 1, can be calculated from the following formula.

[0165] (1) Amount of Si-Vi from PDMS (mole)

[0166] (PDMS addition amount / PDMS molecular weight)×<PDMS molecular weight / {[(D unit molecular weight)×(D unit mol% / 100)]+[(D Vi Unit molecular weight)×(D vi Unit mole % / 100)]}>×(D vi Unit mole % / 100)

[0167] (2) Amount of Si-Vi derived from PVMS with a Vi-based resin structure (mol)

[0168] (PVMS addition amount / PVMS molecular weight)×<PVMS molecular weight / {[(Q unit molecular weight)×(Q unit mol% / 100)]+[(M unit molecular weight)×(M unit mol% / 100)]+[(M Vi Unit molecular weight)×(M Vi Unit mole % / 100)]}>×(M Vi Unit mole % / 100)

[0169] (3) Amount of Si-H from POHS (mole)

[0170] (POHS addition amount / POHS molecular weight)×<PVMS molecular weight / {[(D unit molecular weight)×(D unit mol% / 100)]+[(D H Unit molecular weight)×(D H Unit mole % / 100)]}>×(D H Unit mole % / 100)

[0171] (In the above formula, PDMS: dimethyl polysiloxane, PVMS: resin-structured vinyl methyl polysiloxane, POHS: organohydrogen polysiloxane)

[0172] The Si-H / Si-Vi (molar ratio) of Preparation Example 1 obtained from (1) to (3) above was 1.0.

[0173] [Chemical Formula 2]

[0174]

[0175] [Preparation Example 2]

[0176] 70 parts by mass of dimethylpolysiloxane ((CH3)2SiO2 / 2 Unit (D unit) 97.5 mol%, (CH2=CH)(CH3)SiO 2 / 2 Unit (D Vi 2.5 mol% of units), 30 parts by mass of dimethylpolysiloxane (composed of (CH3)2SiO 2 / 2 Unit (D unit) 99.85 mol%, (CH2=CH)(CH3)SiO 2 / 2 Unit (D Vi To a solution consisting of 200 parts by mass of toluene and 50 parts by mass of vinylmethylpolysiloxane (composed of SiO 4 / 2 Unit (Q unit) 50 mol%, (CH3)3SiO 1 / 2 Unit (M unit) 48 mol% and (CH2=CH)(CH3)2SiO 1 / 2 Unit (M Vi A solution of 100 parts by mass of toluene and 25 parts by mass of an organohydrogenpolysiloxane (composed of (CH3)HSiO 2 / 2 Unit (D H A solution of 30 parts by mass of a dimethylpolysiloxane containing 16.1 mol% of a 30% toluene solution (consisting of 16.1 mol% of a 30% toluene solution) with a molecular chain end-terminated trimethylsiloxy group having a viscosity (25°C) of 5,000 mPa·s was mixed. 0.6 parts by mass of 1-ethynylcyclohexanol was mixed with 0.1 parts by mass of an antioxidant represented by the following formula (M-2). The mixture was then filtered through a 0.2 μm membrane filter to prepare a thermosetting silicone resin solution A2. The viscosity of the resin solution (A2) at 25°C was 1,800 mPa·s. The Si—H / Si—Vi (molar ratio) in Preparation Example 2 was 1.5.

[0177] [Chemical Formula 3]

[0178]

[0179] [Preparation Example 3]

[0180] To 100 parts by mass of dimethylpolysiloxane ((CH3)2SiO 2 / 2 Unit (D unit) 97.5 mol%, (CH2=CH)(CH3)SiO 2 / 2 Unit (D ViTo a solution consisting of 2.5 mol% of SiO units) and 200 parts by mass of toluene, 50 parts by mass of vinylmethylpolysiloxane (composed of SiO 4 / 2 Unit (Q unit) 50 mol%, (CH3)3SiO 1 / 2 Unit (M unit) 48 mol% and (CH2=CH)(CH3)2SiO 1 / 2 Unit (M Vi A solution of 100 parts by mass of toluene and 15 parts by mass of an organohydrogenpolysiloxane (composed of (CH3)HSiO) having an Mn of 2,400 2 / 2 Unit (D H A solution of 20 parts by mass of a dimethylpolysiloxane (comprising 16.1 mol% of 30% by mass toluene solution with a viscosity (25°C) of 100,000 mPa·s at both ends of the molecular chain, 80 parts by mass of toluene, and 0.6 parts by mass of 1-ethynylcyclohexanol, 0.1 parts by mass of an antioxidant represented by the following formula (M-3), and 0.4 parts by mass of toluene were mixed. Subsequently, 0.4 parts by mass of a hydrosilylation catalyst CAT-PL-5 was added to the mixture, and the mixture was filtered through a 0.2 μm membrane filter to prepare a thermosetting silicone resin solution A3. The viscosity of the resin solution (A3) at 25°C was 2,800 mPa·s. The Si—H / Si-Vi (molar ratio) in Preparation Example 3 was 0.7.

[0181] [Chemical Formula 4]

[0182]

[0183] [Preparation Example 4]

[0184] The amount of the antioxidant represented by the formula (M-3) in the above-mentioned Preparation Example 3 was changed from 0.1 parts by mass to 0.05 parts by mass, and the organohydrogen polysiloxane ((CH3)HSiO 2 / 2 Unit (D H A thermosetting silicone resin solution A4 was prepared in the same manner except that the content of the 16.1 mol% unit (composition) was changed from 15 parts by mass to 21 parts by mass. The viscosity of the resin solution (A4) at 25°C was 2,400 mPa·s. The Si—H / Si—Vi (molar ratio) in Preparation Example 4 was 1.0.

[0185] [Preparation Example 5]

[0186] A thermosetting silicone resin solution A5 was prepared in the same manner as in Preparation Example 4, except that the amount of the antioxidant represented by formula (M-3) was changed from 0.1 part by mass to 0.4 part by mass. The viscosity of the resin solution (A5) at 25°C was 2,400 mPa·s. The Si—H / Si—Vi (molar ratio) in Preparation Example 5 was 1.0.

[0187] [Preparation Example 6]

[0188] Photocurable silicone resin solution A6 was prepared in the same manner as in Preparation Example 1, except that a toluene solution of (methylcyclopentadienyl)trimethylplatinum(IV) (platinum concentration: 1.0 mass%) (0.4 mass parts) was added instead of the hydrosilylation catalyst CAT-PL-5 (0.4 mass parts). The viscosity of resin solution (A6) at 25°C was 2,300 mPa·s. The Si—H / Si—Vi (molar ratio) in Preparation Example 6 was 1.0.

[0189] [Preparation Example 7]

[0190] In Preparation Example 2, a photocurable silicone resin solution A7 was prepared in the same manner as above, except that a toluene solution of (methylcyclopentadienyl)trimethylplatinum(IV) (platinum concentration: 1.0 mass%) (0.4 mass parts) was added instead of the hydrosilylation catalyst CAT-PL-5 (0.4 mass parts). The viscosity of the resin solution (A7) at 25°C was 1,800 mPa·s. The Si—H / Si—Vi (molar ratio) in Preparation Example 7 was 1.5.

[0191] [Comparative Preparation Example 1]

[0192] A thermosetting silicone resin solution CA1 was prepared in the same manner as in Preparation Example 1, except that the solution comprising 0.1 parts by mass of the antioxidant represented by Formula (M-1) and 0.4 parts by mass of toluene was not added. The viscosity of the resin solution (CA1) at 25°C was 2,400 mPa·s. The Si—H / Si—Vi (molar ratio) in this Comparative Preparation Example 1 was 1.0.

[0193] [Comparative Preparation Example 2]

[0194] In Preparation Example 1, a thermosetting silicone resin solution CA2 was prepared in the same manner as above, except that 0.1 part by mass of an antioxidant represented by the following formula (M-4) was added instead of 0.1 part by mass of the antioxidant represented by the above formula (M-1). The viscosity of the resin solution (CA2) at 25°C was 2,300 mPa·s. The Si—H / Si—Vi (molar ratio) in this Comparative Preparation Example 2 was 1.0.

[0195] [Chemical Formula 5]

[0196]

[0197] [Comparative Preparation Example 3]

[0198] In Preparation Example 6, a photocurable silicone resin solution CA3 was prepared in the same manner except that 0.1 part by mass of an antioxidant represented by the following formula (M-5) was added instead of 0.1 part by mass of the antioxidant represented by the above formula (M-1). The viscosity of the resin solution (CA3) at 25°C was 2,300 mPa·s. The Si—H / Si—Vi (molar ratio) in this Comparative Preparation Example 3 was 1.0.

[0199] [Chemical Formula 6]

[0200]

[0201] [2] Fabrication and evaluation of wafer stacks

[0202] [Examples 1 to 7 and Comparative Examples 1 to 3]

[0203] On a 200mm diameter silicon wafer (thickness: 725μm) with copper pillars 10μm high and 40μm in diameter formed on the entire surface, curable silicone resin solutions A1 to A7 and CA1 to CA3 were spin-coated, respectively. The wafer was heated in air at 100°C for 2 minutes in an oven, and a temporary adhesive layer was formed on the wafer bump-forming surface with the film thickness shown in Table 1 below. A 200mm diameter glass wafer (thickness: 500μm) was used as a support. The silicon wafer and glass wafer with the temporary adhesive layer were bonded to the glass wafer using EVG's EVG520IS wafer bonding system at 100°C for 2 minutes, 10 minutes, and 10 minutes. -3 The wafers were vacuum bonded under the conditions of a pressure of 1000 mbar or less and a load of 5 kN, and then a curing step was performed to produce a wafer stack. The curing conditions were as follows: when a thermosetting silicone resin solution was used, the wafers were heated in an oven at 180°C for 1 hour; when a photocurable silicone resin solution was used, the wafers were heated in an oven at 180°C for 1 hour; when a surface-illuminated UV-LED (wavelength 365 nm) was used, the wafers were heated at 23°C at 100 mW / cm 2 The light irradiation was performed at an illumination of 1000 nm for 120 seconds.

[0204] [Comparative Examples 4 and 5]

[0205] The curable silicone resin solutions A1 and A6 were applied to a glass wafer support with a diameter of 200 mm (thickness: 500 μm) by spin coating. The solution was then heated in an oven at 100°C in air for 2 minutes to form a temporary adhesive layer on the glass wafer support with the film thickness shown in Table 1 below. Next, a silicon wafer with a diameter of 200 mm (thickness: 725 μm) with copper pillars of 10 μm height and 40 μm diameter formed on the entire surface and the glass wafer with the temporary adhesive layer were bonded together using the EVG520IS wafer bonding device from EVG at 100°C for 2 minutes, 10 minutes, and 10 minutes. -3 The wafer stack was then vacuum bonded under the conditions of a pressure of less than mbar and a load of 5kN, and then cured to produce a wafer stack. The curing conditions were as follows: when a thermosetting silicone resin solution was used, the wafer was heated in an oven at 180°C for 1 hour; when a photocurable silicone resin solution was used, the wafer was heated in an oven at 180°C for 1 hour; when a surface-illuminated UV-LED (wavelength 365nm) was used, the wafer was heated at 23°C at 100mW / cm 2 The light irradiation was performed at an illumination of 1000 nm for 120 seconds.

[0206] Then, various tests were performed on the obtained wafer stack using the following test methods. The results are also shown in Table 1.

[0207] (1) Adhesion test

[0208] In the wafer stack, the bonding condition of the wafer interface was visually checked from the glass support side. If no abnormality such as bubbles was observed at the interface, it was evaluated as good and indicated by "○", and if abnormality was observed, it was evaluated as poor and indicated by "×".

[0209] (2) Back grinding resistance test

[0210] The wafer stack was used to grind the back of the silicon wafer using a grinder (DAG-810 manufactured by DISCO CORPORATION) and a diamond grindstone. After grinding to a thickness of 30 μm, an optical microscope (100 times) was used to investigate the presence or absence of abnormalities such as cracks and peeling. The situation where no abnormality occurred was evaluated as good and indicated by "○", and the situation where an abnormality occurred was evaluated as poor and indicated by "×".

[0211] (3) Heat resistance test in air

[0212] After the back grinding resistance test (2) was completed, the wafer stack was heated in an oven at 250°C in air for 1 hour and then visually inspected for any abnormalities in appearance after cooling to room temperature. No abnormalities in appearance were evaluated as good and indicated by "○". Abnormalities in appearance such as voids, wafer bulging, or wafer breakage were evaluated as poor and indicated by "×".

[0213] (4) Heat resistance test in nitrogen

[0214] After the back grinding resistance test (2) above was completed, the wafer stack was heated in a nitrogen atmosphere in an oven at 250°C for 1 hour, and then visually inspected for any abnormalities in appearance after cooling to room temperature. No abnormalities in appearance were evaluated as good and indicated by "○", while abnormalities in appearance such as voids, wafer bulging, or wafer breakage were evaluated as poor and indicated by "×".

[0215] (5) Peelability test after heat resistance test in air

[0216] Regarding the peelability of the substrate, first, a dicing tape (ELP UB-3083D manufactured by Nitto Denko Corporation.) is attached to the wafer side of the wafer stack after the heat resistance test in air (3) described above using a dicing frame, and the dicing tape surface is placed on an adsorption plate by vacuum adsorption. Then, at room temperature, one point of the glass is clamped with tweezers to peel off the glass wafer. "○" indicates that the 30 μm thick wafer can be peeled off without breaking it, and the case where an abnormality such as cracking occurs is evaluated as poor and indicated by "×". In addition, at this time, it is confirmed on which side of the substrate (silicon wafer) side and the support body (glass wafer) side the temporary adhesive layer remains in the form of residue.

[0217] (6) Peelability test after heat resistance test in nitrogen

[0218] The releasability of the substrate was evaluated using the wafer stack after the heat resistance test in nitrogen (4) described above, in the same manner as the releasability test after the heat resistance test in air (5) described above.

[0219] (7) Cleaning and removal test

[0220] The wafer of 200 mm in diameter on which the adhesion test of the above (5), (6) was completed and which was mounted on a dicing frame via a dicing tape was set on a spin coater with the peeling surface facing upward, and after spraying SPIS-TA-CLEANER 25 (manufactured by Shin-Etsu Chemical Co., Ltd.) as a cleaning solvent for 5 minutes, isopropanol (IPA) was sprayed while rotating the wafer, and thus rinsing was performed. Then, the appearance was observed, and the presence or absence of the remaining adhesive was checked with the naked eye. The case where the presence of the remaining resin was not confirmed was evaluated as good and indicated by "O", and the case where the presence of the remaining resin was confirmed was evaluated as poor and indicated by "X".

[0221] (8) Peeling force test

[0222] On a silicon wafer (thickness: 725 μm) of 200 mm in diameter on which a copper pillar of 10 μm in height and 40 μm in diameter was formed on the entire surface, spin coating was performed for each of the curable silicone resin solutions Al to A7 and CA1 to CA3, and a silicone resin layer was formed on the wafer bump formation surface at a film thickness shown in Table 1 using a hot plate at 100°C for 2 minutes. Then, the silicone resin layer was cured at the conditions shown in Table 1, and after cooling to room temperature, 5 pieces of polyimide tape of 150 mm in length and 25 mm in width were attached to the silicone resin layer on the wafer, and the temporary adhesive layer of the portion to which the tape was not attached was removed. Using AUTOGRAPH (AG-1) of SHIMADZU CORPORATION, 120 mm was peeled from one end of the tape at 180° at a speed of 300 mm / minute at 25°C, and the average (120 mm stroke x 5 times) of the force applied at this time was taken as the initial peeling force of the silicone resin layer. In addition, a cured product of the silicone resin layer was produced on the wafer bump formation surface in the same manner as described above, and the tape peeling force after heat treatment in an oven at 250°C for 1 hour in air was measured as the heat resistance after peeling force.

[0223] (9) Storage modulus measurement

[0224] On a glass wafer, spin coating was performed for each of the curable silicone resin solutions Al to A7 and CA1 to CA3, and a silicone resin layer was formed on the glass wafer at a film thickness shown in Table 1 using a hot plate at 100°C for 2 minutes. Then, the silicone resin layer was cured at the conditions shown in Table 1, and cooled to room temperature. Using Ares G2 manufactured by TA Instruments., the obtained glass wafer including the silicone resin layer was sandwiched with a 25 mmφ aluminum plate in such a manner that a load of 50 gf was applied to the silicone resin layer, and in this state, the elastic modulus measurement at 25°C was performed, and the value of the obtained elastic modulus was taken as the storage modulus of the silicone resin layer.

[0225] (10) Thermogravimetric determination in air

[0226] Appropriate amounts of curable silicone resin solutions A1-A5 and CA1-CA3 were poured into a Teflon (registered trademark)-coated mold measuring 100mm (H) x 100mm (W) x 1mm (D). Excess resin solution was removed with a scraper and then heated at 100°C for 2 minutes on a hot plate. The silicone resin layers were then cured under the conditions shown in Table 1 and cooled to room temperature to produce cured silicone resin layers. 10mg of the resulting cured product was subjected to thermogravimetric measurement in air, and the temperature at which the cured product lost 1% weight was measured. The apparatus used was a TGA2 manufactured by METTLER TOLEDO, and the measurement conditions were 40-400°C (10°C / min.).

[0227] [Table 1]

[0228]

[0229] As shown in Table 1, the temporary adhesive formed from the curable silicone resin composition containing an antioxidant in the Examples of the present invention exhibited sufficient curability and demonstrated excellent wafer processing durability, peel stability after prolonged heat treatment at high temperatures in air, and post-peel cleaning removability. Furthermore, thermogravimetric measurements in air confirmed improved heat resistance stability.

[0230] On the other hand, in Comparative Example 1, which did not contain an antioxidant, no effect was observed during the high-temperature, long-term heat treatment in nitrogen. However, after the high-temperature, long-term heat treatment in air, a negative impact on the subsequent peelability was confirmed. Furthermore, in Comparative Examples 2 and 3, which used antioxidants containing sulfur or phosphorus atoms in their structures, insufficient curing properties were observed, resulting in poor wafer processability.

[0231] In Comparative Examples 4 and 5, where a curable silicone resin composition was applied to a glass carrier as a support to create a bonded structure with a silicon wafer substrate, the process was identical to that of the Examples until the peeling step. However, during peeling, residue from the temporary adhesive layer remained on the substrate, making it impossible to completely remove it using the subsequent cleaning and removal process similar to that of the Examples. However, the residue was completely removed by repeating the cleaning and removal process twice.

[0232] This specification includes the following protocols.

[0233] [1]: A temporary adhesive for wafer processing, which is used for temporarily bonding a wafer to a support, characterized in that:

[0234] The temporary adhesive for wafer processing is composed of a curable silicone resin composition that can be cured by a hydrosilation reaction.

[0235] The curable silicone resin composition includes a phenolic antioxidant that does not contain phosphorus atoms or sulfur atoms.

[0236] [2]: The temporary adhesive for wafer processing according to [1] above, wherein the curable silicone resin composition comprises:

[0237] (A) 100 parts by mass of an organopolysiloxane having two or more alkenyl groups in one molecule;

[0238] (B) an organohydrogenpolysiloxane containing two or more hydrogen atoms bonded to silicon atoms (SiH groups) in one molecule, wherein the total molar ratio of the SiH groups in the component (B) to the total molar ratio of the alkenyl groups in the component (A) is 0.3 to 10;

[0239] (C) 0.1 to 200 parts by mass of a non-functional organopolysiloxane;

[0240] (D) a hydrosilylation catalyst, in an amount of 0.1 to 5,000 ppm based on the total mass of components (A), (B), and (C), calculated as metal atomic weight; and

[0241] (E) The phenolic antioxidant is present in an amount of 1 to 100,000 ppm based on the total mass of the components (A), (B), and (C).

[0242] [3]: The temporary adhesive for wafer processing according to [2] above, wherein the amount of the component (B) is such that the total molar ratio of the SiH groups in the component (B) to the total molar ratio of the alkenyl groups in the component (A) is 0.3 to 5.0.

[0243] [4]: The temporary adhesive for wafer processing according to any one of [1] to [3] above, wherein the curable silicone resin composition can be cured by light and / or heat.

[0244] [5]: The temporary adhesive for wafer processing according to any one of [2] to [4] above, wherein the phenolic antioxidant of the component (E) is a hindered phenolic antioxidant.

[0245] [6]: A temporary adhesive for wafer processing according to any one of [2] to [5] above, wherein the non-functional organopolysiloxane of component (C) is dimethylpolysiloxane, and a 30% by mass toluene solution of component (C) has a viscosity of 100 to 500,000 mPa·s at 25°C.

[0246] [7]: A temporary adhesive for wafer processing according to any one of [2] to [6] above, wherein the curable silicone resin composition containing the phenolic antioxidant further contains 0.001 to 10 parts by mass of a hydrosilylation reaction control agent as component (F) relative to the total mass of the components (A), (B) and (C).

[0247] [8]: A temporary adhesive for wafer processing according to any one of [1] to [7] above, wherein the 180° peeling force of a 25 mm wide test piece relative to a silicon substrate at 25°C after curing of the curable silicone resin composition containing the phenolic antioxidant is greater than or equal to 2 gf and less than or equal to 100 gf.

[0248] [9]: The temporary adhesive for processing according to any one of [1] to [8] above, wherein the storage modulus at 25°C after curing of the curable silicone resin composition containing the phenolic antioxidant is 1,000 Pa or more and 1,000 MPa or less.

[0249]

[10] : A temporary adhesive for wafer processing according to any one of [1] to [9] above, wherein a curable silicone resin composition containing the phenolic antioxidant is applied to the wafer to prepare a laminate, and the peeling interface when peeling the laminate can be controlled to be the interface between the temporary adhesive layer obtained from the temporary adhesive for wafer processing and the wafer.

[0250]

[11] : A temporary adhesive for wafer processing according to any one of [1] to

[10] above, wherein a curable silicone resin composition containing the phenolic antioxidant is applied to the support and a laminate is prepared, and the peeling interface when peeling the laminate can be controlled to be the interface between the temporary adhesive layer obtained from the temporary adhesive for wafer processing and the support.

[0251]

[12] :A method for manufacturing a thin wafer, comprising:

[0252] (a) using the temporary adhesive for wafer processing according to any one of [1] to

[11] above, the circuit-forming surface of a wafer having a circuit-forming surface on its front surface and a non-circuit-forming surface on its back surface is bonded to a support in a releasable manner, thereby forming a wafer stack;

[0253] (b) a step of curing the temporary adhesive;

[0254] (c) grinding or polishing the non-circuit-forming surface of the wafer of the wafer stack;

[0255] (d) a step of processing the non-circuit-forming surface of the wafer; and

[0256] (e) A step of peeling the processed wafer from the support.

[0257]

[13] : A wafer stack comprising a support, a temporary adhesive layer obtained by stacking on the support from the temporary adhesive for wafer processing of any one of [1] to

[11] , and a wafer having a circuit-forming surface on its surface and a non-circuit-forming surface on its back, wherein the temporary adhesive layer is bonded to the surface of the wafer in a removable manner.

[0258] The present invention is not limited to the above-described embodiments, which are merely examples, and any technical solution having substantially the same structure and exhibiting the same effects as the technical concept described in the claims of the present invention is within the scope of protection of the present invention.

Claims

1. A temporary adhesive for wafer processing, which is used for temporarily bonding a wafer to a support, characterized in that: The temporary adhesive for wafer processing is composed of a curable silicone resin composition that can be cured by a hydrosilation reaction. The curable silicone resin composition includes a phenolic antioxidant that does not contain phosphorus atoms or sulfur atoms.

2. The temporary adhesive for wafer processing according to claim 1, wherein The curable silicone resin composition comprises: (A) 100 parts by mass of an organopolysiloxane having two or more alkenyl groups in one molecule; (B) an organohydrogenpolysiloxane containing two or more hydrogen atoms bonded to silicon atoms (SiH groups) in one molecule, wherein the total molar ratio of the SiH groups in the component (B) to the total molar ratio of the alkenyl groups in the component (A) is 0.3 to 10; (C) 0.1 to 200 parts by mass of a non-functional organopolysiloxane; (D) a hydrosilylation catalyst, in an amount of 0.1 to 5,000 ppm based on the total mass of components (A), (B), and (C), calculated as metal atomic weight; and (E) The phenolic antioxidant is present in an amount of 1 to 100,000 ppm based on the total mass of the components (A), (B), and (C).

3. The temporary adhesive for wafer processing according to claim 2, wherein: The amount of the component (B) is such that the total amount of SiH groups in the component (B) is 0.3 to 5.0 in terms of molar ratio relative to the total amount of alkenyl groups in the component (A).

4. The temporary adhesive for wafer processing according to claim 1, wherein The curable silicone resin composition may be cured by light and / or heat.

5. The temporary adhesive for wafer processing according to claim 2, wherein: The phenolic antioxidant as the component (E) is a hindered phenolic antioxidant.

6. The temporary adhesive for wafer processing according to claim 2, wherein: The non-functional organopolysiloxane of the component (C) is dimethylpolysiloxane, and a 30% by mass toluene solution of the component (C) has a viscosity of 100 to 500,000 mPa·s at 25° C.

7. The temporary adhesive for wafer processing according to claim 2, wherein: The curable silicone resin composition containing the phenolic antioxidant further contains 0.001 to 10 parts by mass of a hydrosilylation reaction control agent as the component (F) based on the total mass of the components (A), (B), and (C).

8. The temporary adhesive for wafer processing according to claim 1, wherein The curable silicone resin composition containing the phenolic antioxidant has a 180° peel strength of 2 gf or more and 100 gf or less at 25° C. on a 25 mm wide test piece from a silicon substrate after curing.

9. The temporary adhesive for wafer processing according to claim 1, wherein The curable silicone resin composition containing the phenolic antioxidant has a storage modulus at 25° C. after curing of 1,000 Pa or more and 1,000 MPa or less.

10. The temporary adhesive for wafer processing according to claim 1, wherein By applying the curable silicone resin composition containing the phenolic antioxidant to the wafer to prepare a laminate, the peeling interface when peeling the laminate can be controlled to be the interface between the temporary adhesive layer obtained from the temporary adhesive for wafer processing and the wafer.

11. The temporary adhesive for wafer processing according to claim 1, wherein By applying the curable silicone resin composition containing the phenolic antioxidant to the support to prepare a laminate, the peeling interface during peeling of the laminate can be controlled to be the interface between the temporary adhesive layer obtained from the temporary adhesive for wafer processing and the support.

12. A method for manufacturing a thin wafer, comprising: (a) using the temporary adhesive for wafer processing according to any one of claims 1 to 11, the circuit-forming surface of a wafer having a circuit-forming surface on one surface and a non-circuit-forming surface on the other side is bonded to a support in a releasable manner to form a wafer stack; (b) a step of curing the temporary adhesive; (c) grinding or polishing the non-circuit-forming surface of the wafer of the wafer stack; (d) a step of processing the non-circuit-forming surface of the wafer; and (e) A step of peeling the processed wafer from the support.

13. A wafer stack comprising a support, a temporary adhesive layer obtained by laminating on the support and comprising the temporary adhesive for wafer processing according to any one of claims 1 to 11, and a wafer having a circuit-formed surface on one surface and a non-circuit-formed surface on the other, wherein: The temporary adhesive layer is adhered to the surface of the wafer in a releasable manner.

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