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

Abstract

Provided is a wafer processing temporary adhesive for temporarily bonding a wafer to a support, a wafer processing body, and a method for manufacturing a thin wafer using the wafer processing temporary adhesive, which contain a photocurable silicone resin composition containing an unfunctional organic polysiloxane.

Description

TECHNICAL FIELD

[0001] The present application relates to a temporary adhesive for wafer processing, a wafer laminate, and a manufacturing method of a thin wafer. BACKGROUND

[0002] In order to achieve higher density and larger capacity, 3-dimensional semiconductor packaging is becoming indispensable. The so-called 3-dimensional packaging technology is a semiconductor manufacturing technology in which a semiconductor chip is thinned, and then, while being made conductive by a through silicon via (TSV), it is laminated into multiple layers. In order to achieve this, the following processes are required: thinning of a substrate in which a semiconductor circuit is formed by grinding a non-circuit formation surface (also referred to as a back surface), and then, formation of an electrode including a TSV on the back surface. In the past, in the back surface grinding process of a silicon substrate, a back surface protection tape is attached to the opposite side of the ground surface to prevent breakage of the wafer during grinding. However, although this tape uses an organic resin film as a support base material, it has insufficient strength and heat resistance, and is not suitable for performing the TSV formation process and the wiring layer formation process on the back surface.

[0003] Therefore, a system that can sufficiently withstand the back surface grinding, TSV, and back surface electrode formation processes by joining a semiconductor substrate to a support such as silicon or glass via an adhesive layer has been proposed. At this time, the adhesive layer when joining the substrate to the support is important. It is necessary to join the substrate to the support without gaps, to have sufficient durability to withstand the subsequent processes, and to be able to easily peel off the thin wafer from the support at the end. Therefore, since peeling off at the end, in this specification, this adhesive layer is also referred to as a temporary adhesive layer.

[0004] As a currently known temporary adhesive layer and its peeling method, a technology in which an adhesive layer is peeled off from a support by irradiating high-intensity light to an adhesive containing a light-absorbing substance to decompose the adhesive layer (Patent Literature 1), and a technology in which a thermally fusible hydrocarbon compound is used in the adhesive, and joining / peeling is performed in a heated and molten state (Patent Literature 2) have been proposed. In the former technology, there are problems such as the need for an expensive device such as a laser, and the processing time per 1 substrate becomes long. In addition, in the latter technology, since control is performed only by heating, it is simple, but since the heat stability is insufficient at a high temperature of 200°C or more, the range of application is narrow. Furthermore, these temporary adhesive layers are also not suitable for forming a uniform film thickness and complete adhesion to the support on a substrate with a large difference in height.

[0005] A technique of using a silicone pressure-sensitive adhesive in a temporary adhesive material layer has been proposed, but it is a technique of joining a substrate to a support body using a heat-curable silicone pressure-sensitive adhesive, immersing in a chemical capable of dissolving or decomposing a silicone resin at the time of peeling, and separating the substrate from the support body (Patent Document 3). Therefore, a very long time is required for peeling, and it is difficult to apply to actual manufacturing processes. In addition, a long time is also required for cleaning the silicone pressure-sensitive adhesive remaining as a residue on the substrate after peeling, and there are problems from the viewpoint of cleaning removal properties and the like. On the other hand, in the joining process, heating at around 150°C is required in the case of a heat-curable silicone, and in particular, in the case of heating on a hot plate, warping of the wafer sometimes becomes a problem. Therefore, in the case of attempting to join at a low temperature in order to suppress warping of the wafer, there are problems that completion of curing requires a long time and the like.

[0006] Prior Art Documents

[0007] Patent Documents

[0008] Patent Document 1: Japanese Patent Application Laid-Open (JP-A) No. 2004-64040

[0009] Patent Document 2: Japanese Patent Application Laid-Open (JP-A) No. 2006-328104

[0010] Patent Document 3: U.S. Patent No. 7541264 SUMMARY

[0011] PROBLEMS TO BE SOLVED BY THE INVENTION

[0012] The present application has been achieved in view of the above problems, and aims to provide a temporary adhesive for wafer processing, a wafer laminate, and a manufacturing method of a thin wafer using the same, which can join a substrate to a support body at a lower temperature and in a short time, thereby improving workability at the time of joining, wafer warping, and the like, and even in the case of using a substrate having a large difference in level, the substrate retention property after joining is sufficient, process adaptability to a wafer backgrinding process, a TSV forming process, and a wafer back wiring process is high, resistance to wafer thermal processes is also excellent, on the other hand, peeling is easy in the peeling process, and the cleaning property of a residue on the substrate after peeling is also excellent, and the like, and contributes to improvement in productivity of thin wafers.

[0013] MEANS FOR SOLVING THE PROBLEMS

[0014] The present inventors have intensively studied in order to solve the above problems, and as a result, have found that the above problems can be solved by using a photocurable silicone resin composition containing an unfunctionalized organopolysiloxane in a temporary adhesive, and have completed the present application.

[0015] Accordingly, the present application provides a wafer processing temporary adhesive, wafer laminate, and thin wafer manufacturing method described below.

[0016] 1. A wafer processing temporary adhesive for temporarily bonding a wafer to a support, comprising a photocurable silicone resin composition containing a non-functional organopolysiloxane.

[0017] 2. The wafer processing temporary adhesive according to 1, wherein the photocurable silicone resin composition containing a non-functional organopolysiloxane comprises:

[0018] (A) an organopolysiloxane having 2 or more alkenyl groups in 1 molecule: 100 parts by mass,

[0019] (B) an organohydrogenpolysiloxane containing 2 or more silicon atom-bonded hydrogen atoms (SiH groups) in 1 molecule: an amount satisfying a total of SiH groups in the (B) component relative to a total of alkenyl groups in the (A) component in a molar ratio of 0.3 to 10,

[0020] (C) a non-functional organopolysiloxane: 0.1 to 200 parts by mass, and

[0021] (D) a photoactive hydrosilylation reaction catalyst: 0.1 to 5000 ppm in terms of metal atom amount relative to a total mass of the (A), (B), and (C) components.

[0022] 3. The wafer processing temporary adhesive according to 2, wherein a 30% toluene solution of the non-functional organopolysiloxane of the (C) component has a viscosity of 100 to 500,000 mPa-s at 25°C.

[0023] 4. The wafer processing temporary adhesive according to any one of 1 to 3, wherein the photocurable silicone resin composition containing a non-functional organopolysiloxane further comprises 0.001 to 10 parts by mass of a hydrosilylation reaction control agent as an (E) component relative to a total mass of the (A), (B), and (C) components.

[0024] 5. The wafer processing temporary adhesive according to any one of 1 to 4, wherein a 25 mm wide test piece has a peel strength of 2 gf or more and 50 gf or less at 25°C for a 180° peel from a silicon substrate after curing of the photocurable silicone resin composition containing a non-functional organopolysiloxane.

[0025] 6. The wafer processing temporary adhesive according to any one of 1 to 5, wherein the photocurable silicone resin composition containing a non-functional organopolysiloxane has a storage modulus of 1,000 Pa or more and 1,000 MPa or less at 25°C after curing.

[0026] 7. A method for manufacturing a thin wafer using the photocurable silicone resin composition containing an unfunctional organic polysiloxane, wherein in a process (processes (a), (b) hereinafter) of joining and curing a wafer to a support body via a temporary adhesive layer, any one of the following modes is included. Here, the processes (c) to (e) are common to any one of the modes.

[0027] (Mode 1)

[0028] (a1) a process of joining the circuit formation surface of a wafer having a circuit formation surface on the front surface and a non-circuit formation surface on the back surface, and / or the joining surface of a support body to the wafer, by applying the wafer processing temporary adhesive composition according to any one of 1 to 6,

[0029] (b1) a process of photocuring the temporary adhesive of the joined wafer,

[0030] (Mode 2)

[0031] (a2) a process of light-irradiating the wafer processing temporary adhesive composition according to any one of 1 to 6,

[0032] (b2) a process of joining and curing the circuit formation surface of a wafer having a circuit formation surface on the front surface and a non-circuit formation surface on the back surface, and / or the joining surface of a support body to the wafer, by applying the wafer processing temporary adhesive composition subjected to light-irradiation in (a2),

[0033] (c) a process of grinding or polishing the non-circuit formation surface of the wafer of the wafer laminate,

[0034] (d) a process of performing processing on the non-circuit formation surface of the wafer,

[0035] (e) a process of peeling the wafer subjected to processing from the support body.

[0036] 8. A wafer laminate comprising: a support body, a temporary adhesive layer obtained from the wafer processing temporary adhesive according to any one of 1 to 6 laminated thereon, and a wafer having a circuit formation surface on the front surface and a non-circuit formation surface on the back surface,

[0037] the temporary adhesive layer is peelably adhered to the front surface of the wafer.

[0038] Effects of the Invention

[0039] The wafer processing temporary adhesive of the present application can perform the bonding of a substrate at a lower temperature and in a short time by light irradiation by using a photocurable silicone resin composition containing a non-functional organopolysiloxane, as a result of which it can suppress the warping of a wafer at the time of bonding and also shorten the bonding time. In addition, after bonding, needless to say, there is no thermal decomposition of the resin, and in particular, there is no flow of the resin even at a high temperature of 200°C or higher, and thus the heat resistance is high. Therefore, it can be applied to a wide range of semiconductor film formation processes, and the resistance to CVD (chemical vapor deposition) is also excellent; in addition, for a wafer having a step, it is also possible to form a temporary adhesive layer having high film thickness uniformity, and due to this film thickness uniformity, it is possible to easily manufacture a uniform thin wafer of 50 μm or less. Furthermore, by using a non-functional organopolysiloxane, the peelability is also excellent, and thus, after manufacturing a thin wafer, it is possible to easily peel the wafer from the support, for example, at room temperature, and it is possible to easily manufacture a fragile thin wafer. In addition, since the temporary adhesive of the present application can be selectively bonded to the support, after peeling, there is no residue from the temporary adhesive remaining on the thin wafer, and the cleaning removability after that is also excellent. According to the thin wafer manufacturing method of the present application, it is possible to easily manufacture a thin wafer having a through electrode structure or a bump connection structure. BRIEF DESCRIPTION OF DRAWINGS

[0040] Figure 1 is an explanatory diagram showing the steps of the thin wafer manufacturing method of the present application. DETAILED DESCRIPTION

[0041] [Temporary adhesive for wafer processing]

[0042] The temporary adhesive for wafer processing of the present application contains a photocurable silicone resin composition containing a non-functional organopolysiloxane. From the viewpoint of the applicability to a silicon wafer or the like having a step, it is suitable to use a silicone resin composition having good spin coatability as a temporary adhesive for wafer processing.

[0043] As such a photocurable silicone resin composition, for example, a composition containing the following (A) to (D) components is preferable.

[0044] (A) organopolysiloxane having 2 or more alkenyl groups in 1 molecule: 100 parts by mass,

[0045] (B) organohydrogenpolysiloxane containing 2 or more silicon atom-bonded hydrogen atoms (SiH groups) in 1 molecule: an amount satisfying that the total of SiH groups in the (B) component is 0.3 to 10 in terms of molar ratio to the total of alkenyl groups in the (A) component,

[0046] (C) non-functional organopolysiloxane: 0.1 to 200 parts by mass, and

[0047] (D) photoactive hydrosilylation reaction catalyst: 0.1 to 5000 ppm in terms of the amount of metal atom, relative to the total mass of the components (A), (B), and (C).

[0048] [(A) component]

[0049] The (A) component is an organopolysiloxane having two or more alkenyl groups in one molecule. As the (A) component, mention can be made of linear or branched diorganopolysiloxane containing two or more alkenyl groups in one molecule, three-dimensional network-structured organopolysiloxane having a three-dimensional network structure of siloxane units (Q units) represented by SiO 4 / 2 units (Q units) represented by SiO

[0050] As such organopolysiloxane, mention can be made of organopolysiloxane represented by the following formula (A-1), (A-2), or (A-3). They can be used alone or in combination of two or more.

[0051] [Chemical Formula 1]

[0052]

[0053]

[0054]

[0055] In formulae (A-1) to (A-3), R 1 to R 16 are each independently a monovalent hydrocarbon group other than an aliphatic unsaturated hydrocarbon group. X 1 to X 5 are each independently an alkenyl group-containing monovalent organic group.

[0056] In formula (A-1), a and b are each independently an integer of 0 to 3. In formulae (A-1) and (A-2), c 1 , c 2 , d 1 , and d 2 are integers satisfying 0 ≤ c 1 ≤ 10, 2 ≤ c 2 ≤ 10, 0 ≤ d 1 ≤ 100, and 0 ≤ d 2 ≤ 100. Among them, a + b + c 1 ≥ 2. a, b, c 1 , c2 , d 1 and d 2 The combination is preferably such that the content of alkenyl groups is a number of 0.6 to 9 mol%.

[0057] In formula (A-3), e is an integer of 1 to 3.f 1 , f 2 and f 3 is such that (f 2 +f 3 ) / f 1 is a number of 0.3 to 3.0, and f 3 / (f 1 +f 2 +f 3 ) is a number of 0.01 to 0.6.

[0058] As the monovalent hydrocarbon group other than the above-mentioned aliphatically 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, t-butyl, n-pentyl, n-hexyl, and the like; cycloalkyl groups such as cyclopentyl, cyclohexyl, and the like; aryl groups such as phenyl, tolyl, and the like. Among these, an alkyl group such as methyl or a phenyl group is preferred.

[0059] As the above-mentioned monovalent organic group containing an alkenyl group, an organic group having 2 to 10 carbon atoms is preferred, and examples thereof include alkenyl groups such as vinyl, allyl, hexenyl, octenyl, and the like; (meth)acrylalkyl groups such as acrylpropyl, acryylethyl, acrylmethyl, methacrylpropyl, and the like; (meth)acryloxyalkyl groups such as acryloxypropyl, acryloxyethyl, acryloxy- methyl, methacryloxypropyl, methacryloxyethyl, methacryloxy- methyl, and the like; monovalent hydrocarbon groups containing an alkenyl group such as cyclohexenylethyl, vinyloxypropyl, and the like. Among these, from an industrial viewpoint, a vinyl group is preferred.

[0060] In formula (A-1), a and b are each independently an integer of 0 to 3, but if a and b are 1 to 3, the molecular chain ends are blocked by alkenyl groups, so that the reaction can be completed in a short time by the molecular chain end alkenyl groups which have a high reactivity, and thus are preferred. In addition, from a cost aspect, a and b are preferably 1 in industry. The alkenyl group-containing diorganopolysiloxane represented by formula (A-1) or (A-2) is preferably in an oil or raw rubber state.

[0061] 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, but from a cost aspect, 1 is preferred in industry. In addition, the average value of e and f 3 / (f 1 +f 2 +f 3The product of the number of SiH groups in the (A) component and the number of SiVi groups in the (B) component is preferably 0.02 to 1.5, more preferably 0.03 to 1.0. The organopolysiloxane represented by formula (A-3) can be used as a solution obtained by dissolving in an organic solvent.

[0062] The number average molecular weight (Mn) of the organopolysiloxane of the (A) component is preferably 100 to 1,000,000, more preferably 1,000 to 100,000. If Mn is within the above range, it is preferable in terms of operability relating to the viscosity of the composition, and processability relating to the storage modulus after curing. Note that, in the present application, Mn is a polystyrene conversion measurement value obtained by gel permeation chromatography using toluene as a solvent.

[0063] As the (A) component, one kind can be used alone, or two or more kinds can be used in combination. In particular, it is preferable to use the organopolysiloxane represented by formula (A-1) and the organopolysiloxane represented by formula (A-3) in combination. At this time, the amount of use of the organopolysiloxane represented by formula (A-3) is preferably 1 to 1,000 parts by mass, more preferably 10 to 500 parts by mass, relative to 100 parts by mass of the organopolysiloxane represented by formula (A-1).

[0064] [(B) component]

[0065] The (B) component is a crosslinking agent, and is an organohydrogenpolysiloxane having at least two, preferably three or more, silicon atom-bonded hydrogen atoms (SiH groups) in one molecule. The above organohydrogenpolysiloxane can be any one of a linear shape, a branched shape, and a cyclic shape. In addition, as the above organohydrogenpolysiloxane, one kind can be used alone, or two or more kinds can be used in combination.

[0066] The viscosity at 25°C of the organohydrogenpolysiloxane of the (B) component is preferably 1 to 5,000 mPa-s, more preferably 5 to 500 mPa-s. Note that, in the present application, the viscosity is a measurement value at 25°C using a rotational viscometer.

[0067] The Mn of the organohydrogenpolysiloxane of the (B) component is preferably 100 to 100,000, more preferably 500 to 10,000. If Mn is within the above range, it is preferable in terms of operability relating to the viscosity of the composition, and processability relating to the storage modulus after curing.

[0068] (B) component is preferably compounded in a manner that the total of SiH groups in the (B) component is in a range of 0.3 to 10 in terms of a molar ratio (SiH group / alkenyl group) with respect to the total of alkenyl groups in the (A) component, and more preferably in a range of 1.0 to 8.0. If the above molar ratio is 0.3 or more, the crosslinking density does not become low, and problems such as non-curing of the temporary adhesive layer do not occur. In addition, if the above molar ratio is 10 or less, the crosslinking density does not become excessively high, and sufficient adhesion and tack can be obtained, and the usable time of the processing liquid can be extended.

[0069] [(C) component]

[0070] The (C) component is a non-functional organopolysiloxane. Here, the "non-functional" means that no reactive group such as an alkenyl group, a hydrogen atom, a hydroxyl group, an alkoxy group, a halogen atom, an epoxy group, or the like is directly bonded to a silicon atom or bonded via any group within the molecule.

[0071] As such a non-functional organopolysiloxane, for example, an organopolysiloxane having a monovalent hydrocarbon group other than an aliphatic unsaturated hydrocarbon group, which is unsubstituted or substituted, and which has 1 to 12, preferably 1 to 10 carbon atoms can be exemplified. As such a monovalent hydrocarbon group, for example, an alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, and the like; a cycloalkyl group such as a cyclohexyl group; an aryl group such as a phenyl group, a tolyl group, a xylyl group, a naphthyl group, and the like; an aralkyl group such as a benzyl group, a phenethyl group, and the like can be exemplified. In addition, part or all of the hydrogen atoms of these groups can be substituted with a halogen atom such as a chlorine atom, a fluorine atom, a bromine atom, and the like, and as such a group, a halogenated alkyl group such as a chloromethyl group, a 3-chloropropyl group, a 3,3,3-trifluoropropyl group, and the like can be exemplified. As the above monovalent hydrocarbon group, an alkyl group and an aryl group are preferred, and a methyl group and a phenyl group are more preferred.

[0072] The molecular structure of the non-functional organopolysiloxane of the (C) component is not particularly limited, and can be any of a linear shape, a branched shape, a cyclic shape, and the like, but an organopolysiloxane of a linear shape or a branched shape is preferred, and a linear diorganopolysiloxane in which the main chain is composed of a repeating diorganosiloxane unit, and both ends of the molecular chain are capped with a triorganosiloxy group is preferred.

[0073] From the viewpoints of the handleability of the composition, the coatability to a substrate, the mechanical properties of the cured product, the releasability from a support, and the like, the viscosity (25°C) of a 30 mass% toluene solution of the non-functional organopolysiloxane of the (C) component is preferably 100 to 500,000 mPa-s, and more preferably 200 to 100,000 mPa-s. If it is within the above range, since it has an appropriate molecular weight, cases where the effect is difficult to obtain due to volatilization when the silicone resin composition is heat-cured, or cases where wafer cracking occurs in wafer thermal processes such as CVD do not occur, and the handleability and the coatability are both good, and thus it is preferred.

[0074] As the above-mentioned non-functional organopolysiloxane, there can be mentioned a dimethylsiloxane polymer having both terminals of the molecular chain capped with trimethylsiloxy groups, a phenylmethylpolysiloxane having both terminals of the molecular chain capped with trimethylsiloxy groups, a 3,3,3-trifluoropropylmethylsiloxane polymer having both terminals of the molecular chain capped with trimethylsiloxy groups, a dimethylsiloxane / methylphenylsiloxane copolymer having both terminals of the molecular chain capped with trimethylsiloxy groups, a dimethylsiloxane / 3,3,3-trifluoropropylmethyl copolymer having both terminals of the molecular chain capped with trimethylsiloxy groups, a methylphenylsiloxane / 3,3,3-trifluoropropylmethyl copolymer having both terminals of the molecular chain capped with trimethylsiloxy groups, a dimethylsiloxane / 3,3,3-trifluoropropylmethylsiloxane / methylphenylsiloxane copolymer having both terminals of the molecular chain capped with trimethylsiloxy groups, a dimethylpolysiloxane having both terminals of the molecular chain capped with dimethylphenylsiloxy groups, a methylphenylpolysiloxane having both terminals of the molecular chain capped with dimethylphenylsiloxy groups, a dimethylsiloxane / methylphenylsiloxane copolymer having both terminals of the molecular chain capped with dimethylphenylsiloxy groups, and the like.

[0075] The non-functional organopolysiloxane of the (C) component can be used alone or in combination of two or more. In addition, it is preferably in the form of an oil or a raw rubber.

[0076] [(D) component]

[0077] The (D) component is a photoactive hydrosilylation reaction catalyst which is activated by irradiation of light, particularly ultraviolet light having a wavelength of 300 to 400 nm, to promote 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 dependency, and a high promotion effect is obtained at a higher temperature. Therefore, from the aspect of completing the reaction within an appropriate reaction time, it is preferable to use at an ambient temperature of 0 to 200°C, more preferably 10 to 100°C, after irradiation of light.

[0078] The photoactive hydrosilylation reaction catalyst is mainly a platinum group metal catalyst or an iron group metal catalyst, and as the platinum group metal catalyst, there are metal complexes of platinum, palladium, and rhodium, and as the iron group metal catalyst, there are iron group complexes of nickel, iron, and cobalt. Among them, the platinum group metal complex is preferable and is often used because it is easily available and exhibits a good catalytic activity.

[0079] In addition, as the ligand, from the aspect of suppressing damage to the wafer, a ligand which exhibits a catalytic activity under UV light having a medium wavelength to long wavelength in the UV-B to UV-A range is preferable. As such a ligand, there can be mentioned a cyclic diene ligand, a β-diketone ligand, and the like.

[0080] As the preferred examples of the photoactive hydrosilylation reaction catalyst, as the cyclic diene ligand type, for example, (η 5 - cyclopentadienyl)tris(σ-alkyl) platinum (IV) complexes, and particularly specifically, (methylcyclopentadienyl)trimethyl platinum (IV), (cyclopentadienyl)trimethyl platinum (IV), (1,2,3,4,5-pentamethylcyclopentadienyl)trimethyl platinum (IV), (cyclopentadienyl)dimethyl ethyl platinum (IV), (cyclopentadienyl)dimethyl acetyl platinum (IV), (trimethylsilylcyclopentadienyl)trimethyl platinum (IV), (methoxycarbonylcyclopentadienyl)trimethyl platinum (IV), (dimethylphenylsilylcyclopentadienyl)trimethyl platinum (IV), and the like, and as the β-diketone ligand type, β-diketone platinum (II) or platinum (IV) complexes, and particularly specifically, trimethyl(acetylacetone) platinum (IV), trimethyl(3,5-heptanedione) platinum (IV), trimethyl(methyl acetoacetate) 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(l-phenyl-l,3-butanedione) platinum (II), bis(l,3-diphenyl-l,3-propanedione) platinum (II), bis(hexafluoroacetylacetone) platinum (II), and the like.

[0081] In the case of using these catalysts, in the case where it is a solid catalyst, it can be used as a solid, but in order to obtain a more uniform cured product, it is preferable to make the catalyst dissolved in a suitable solvent compatible with the organopolysiloxane having an alkenyl group of the (A) component and use it.

[0082] As the solvent, isononyl, toluene, 2-(2-butoxyethoxy)ethyl acetate, and the like can be exemplified.

[0083] The addition amount of the (D) component is an effective amount, but generally, it is 0.1 to 5000 ppm, preferably 0.5 to 2000 ppm, and further preferably 1 to 500 ppm, in terms of the platinum component (metal atomic weight conversion) with respect to the total mass of (A), (B), and (C). If it is 0.1 ppm or more, the curability of the composition does not decrease, the crosslinking density does not become low, and the retention does not decrease. If it is 0.5% or less, the usable time of the treatment bath can be extended.

[0084] [(E) component]

[0085] The above-mentioned photocurable silicone resin composition can further include a reaction control agent as the (E) component. The reaction control agent is an ingredient that is optionally added as needed in order not to cause thickening or gelation of the composition at the time of preparing the composition or coating on a substrate.

[0086] As the above-mentioned reaction control agent, 3-methyl-1-butyne-3-ol, 3-methyl-1-pentyne-3-ol, 3,5-dimethyl-1-hexyne-3-ol, 1-ethynylcyclohexanol, 3-methyl-3-trimethylsilyloxy-1-butyne, 3-methyl-3-trimethylsilyloxy-1-pentyne, 3,5-dimethyl-3-trimethylsilyloxy-1-hexyne, 1-ethynyl-1-trimethylsilyloxycyclohexane, bis(2,2-dimethyl-3-butyloxy)dimethylsilane, 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane, 1,1,3,3-tetramethyl-1,3-divinyl disiloxane, and the like can be exemplified. Among them, 1-ethynylcyclohexanol and 3-methyl-1-butyne-3-ol are preferred.

[0087] In the case where the above-mentioned photocurable silicone resin composition contains the (E) component, the ability varies depending on the chemical structure, and therefore the content thereof should be adjusted to the most suitable amount for each, but if the influence on the curability, storage stability, and physical properties after curing, and the like are taken into consideration, the content thereof is preferably 0.001 to 10 parts by mass, more preferably 0.01 to 10 parts by mass, relative to the total mass of the above-mentioned (A), (B), and (C) components. If the content of the (E) component is within the above-mentioned range, the usable time of the composition is long, long-term storage stability is obtained, and the curability and workability are good.

[0088] In the above-mentioned photocurable silicone resin composition, R A 3SiO 0.5 units (in the formula, R A each independently is an unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms) and SiO2units, R A 3SiO 0.5 units relative to the SiO2units (molar ratio (R A 3SiO 0.5 / SiO2) is 0.3 to 1.8. The addition amount thereof is preferably 0 to 500 parts by mass, relative to 100 parts by mass of the (A) component. Further preferably, it is greater than 0 to 300 parts by mass.

[0089] In order to further improve the heat resistance of the temporary adhesive layer thus obtained, a filler such as silica can be added to the above-mentioned photocurable silicone resin composition within a range not impairing the properties thereof.

[0090] From the viewpoint of the improvement in the operability, the improvement in the miscibility, the adjustment of the film thickness of the temporary adhesive layer, etc. resulting from the reduction in the viscosity of the photocurable silicone resin composition, the composition can be used in the form of a solution by adding a solvent. The solvent used is not particularly limited as long as it can dissolve the above components, but for example, a hydrocarbon-based solvent such as pentane, hexane, cyclohexane, isooctane, nonane, decane, p-menthane, pinene, isododecane, limonene, etc. is preferred.

[0091] As the method of forming a solution, the following methods can be mentioned: a method in which the above photocurable silicone resin composition is prepared and then a solvent is added at the end to adjust the viscosity to the desired value; a method in which the components (A), (B), and / or (C) having a high viscosity are diluted in advance with a solvent to improve the operability and the miscibility, and then the remaining components are mixed. In addition, as the mixing method at the time of forming a solution, an appropriate mixing method can be selected from a vibration mixer, a magnetic stirrer, various mixers, etc. in consideration of the viscosity and the operability of the composition.

[0092] The amount of the solvent to be added is appropriately set from the viewpoint of adjusting the viscosity, the operability, the film thickness of the temporary adhesive layer, etc. of the composition, but for example, 5 to 900 parts by mass, more preferably 10 to 400 parts by mass, relative to 100 parts by mass of the photocurable silicone resin composition is preferred.

[0093] The above photocurable silicone resin composition can be applied to a substrate by a method such as spin coating, roll coating, etc. to form a temporary adhesive layer. In the case where a temporary adhesive layer is formed on a substrate by a method such as spin coating, etc., it is preferred that the above photocurable silicone resin composition be formed into a solution and then applied.

[0094] From the viewpoint of the coatability, the viscosity of the photocurable silicone resin composition formed into a solution at 25°C is preferably 1 to 100,000 mPa-s, more preferably 10 to 10,000 mPa-s.

[0095] In the case of the above photocurable silicone resin composition, after curing, the peel strength at 180° peeling of a test piece (for example, a silicon substrate test piece) having a width of 25 mm at 25°C is generally 2 to 50 gf, preferably 3 to 30 gf, further preferably 5 to 20 gf. If it is 2 gf or more, the wafer will not be shifted when being ground; if it is 50 gf or less, the wafer will be easily peeled.

[0096] In the case of the photocurable silicone resin composition, the storage modulus after curing is 1000 Pa or more and 1000 MPa or less at 25°C, and is preferably 10000 Pa or more and 500 MPa or less. If the storage modulus is 1000 Pa or more, the film formed is strong and flexible, and wafer shift and wafer breakage accompanying the same do not occur during polishing of the wafer. If the storage modulus is 1000 MPa or less, the deformation stress during a wafer thermal process such as CVD is alleviated, and the wafer is stable during the thermal process.

[0097] [Method for manufacturing thin wafer]

[0098] The method for manufacturing a thin wafer of the present application is characterized in that, as an adhesive layer of a wafer having a semiconductor circuit or the like and a support, a temporary adhesive material layer containing a photocurable silicone resin composition is used. Here, two modes and their schematic illustrations are shown in Figure 1 In either mode, 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.

[0099] The method for manufacturing a thin wafer of the present application has the following (al) to (e) as a first mode. In addition, (f) to (i) are provided as needed.

[0100] [Process (al)]

[0101] Process (al) is a temporary adhesive process, and is a process of forming a wafer laminate by peelably adhering the circuit formation surface of a wafer having a circuit formation surface on the front surface and a non-circuit formation surface on the back surface to a support using the above-mentioned temporary adhesive for wafer processing.

[0102] Specifically, any of the following methods can be applied: a method of forming a temporary adhesive layer on the front surface of the above-mentioned wafer using the above-mentioned temporary adhesive for wafer processing, and adhering the support to the front surface of the above-mentioned wafer via the temporary adhesive layer; a method of forming a temporary adhesive layer on the front surface of the support using the above-mentioned temporary adhesive for wafer processing, and adhering the support to the front surface of the above-mentioned wafer via the temporary adhesive layer; and a method of forming temporary adhesive layers on both the front surface of the above-mentioned wafer and the front surface of the support using the above-mentioned temporary adhesive for wafer processing, and adhering the support to the front surface of the above-mentioned wafer via the temporary adhesive layers.

[0103] The wafer that can be applied to the present application is typically a semiconductor wafer. As examples of the above-mentioned semiconductor wafer, not only a silicon wafer, but also a germanium wafer, a gallium-arsenic wafer, a gallium-phosphorus wafer, a gallium-arsenic-aluminum wafer, and the like can be listed. The thickness of the above-mentioned wafer is not particularly limited, but is typically 600 to 800 μm, and more typically 625 to 775 μm.

[0104] In the first mode of the present application, since the light irradiation of the photocurable silicone resin composition is performed by the support, as the support, a substrate having light transmittance such as a glass plate, a quartz plate, an acrylic resin plate, a polycarbonate plate, a polyethylene terephthalate plate, and the like can be used. Among them, the glass plate has light transmittance to ultraviolet rays and excellent heat resistance, and thus is preferred.

[0105] The temporary adhesive layer can be formed by laminating the product obtained by molding the above-mentioned photocurable silicone resin composition into a film to a wafer or a support, or can be formed by coating the above-mentioned photocurable silicone resin composition using a spin coating, a roll coating, or the like. In the case where the above-mentioned photocurable silicone resin composition is a solution containing a solvent, after coating, a preliminary baking is performed at a temperature of preferably 20 to 200°C, more preferably 30 to 150°C, according to the volatilization conditions of the solvent, and then used.

[0106] The above-mentioned temporary adhesive layer is preferably used by being formed into a film thickness of 0.1 to 500 μm, preferably 1.0 to 200 μm. If the film thickness is 0.1 μm or more, in the case of coating on a substrate, a portion where coating is not performed is not generated and thus the entire coating can be performed. On the other hand, if the film thickness is 500 μm or less, the grinding process at the time of forming a thin wafer can be tolerated.

[0107] As a method of attaching the support and the front surface of the wafer via the above-mentioned temporary adhesive layer, a method of uniformly pressure bonding under reduced pressure in a temperature range of preferably 0 to 200°C, more preferably 20 to 100°C can be exemplified.

[0108] The pressure at the time of pressure bonding the wafer on which the temporary adhesive layer is formed and the support varies depending on the viscosity of the temporary adhesive layer, but is preferably 0.01 to 10 MPa, more preferably 0.05 to 1.0 MPa. If the pressure is 0.01 MPa or more, the circuit formation surface and the wafer-support can be filled with the temporary adhesive layer, and if it is 10 MPa or less, the wafer is not broken and the flatness of the wafer and the temporary adhesive layer is not deteriorated, and the subsequent wafer processing is good.

[0109] The attachment of the wafer can be performed using a commercially available wafer bonder such as EVG520IS, 850TB of EVG Corporation, XBS300 of SUSS MicroTec Corporation, and the like.

[0110] [Process (b1)]

[0111] The process (b1) is a process of photo-curing the temporary adhesive layer. After the wafer processed body (laminated substrate) is formed, light is irradiated from the support body side having light transmissivity to photo-cure the temporary adhesive layer. The type of active light at this time is not particularly limited, but is preferably ultraviolet light, and further preferably ultraviolet light having a wavelength of 300 to 400 nm. In terms of the amount of ultraviolet light irradiation (irradiance), it is desirable to be 100 mJ / cm 2 ~ 100000 mJ / cm 2 , preferably 500 mJ / cm 2 ~ 10000 mJ / cm 2 , more preferably 1000 to 5000 mJ / cm 2 If the amount of ultraviolet light irradiation (irradiance) is equal to or greater than the above range, sufficient energy is obtained to activate the photoactive hydrosilylation reaction catalyst in the temporary adhesive layer, and a sufficient cured product is obtained. On the other hand, if the amount of ultraviolet light irradiation (irradiance) is less than the above range, sufficient energy is not irradiated to the composition, and decomposition of the components in the polymer layer or inactivation of a part of the catalyst does not occur, and a sufficient cured product is obtained.

[0112] The ultraviolet light irradiation can be light having a plurality of emission spectra, or light having a single emission spectrum. In addition, the single emission spectrum can have a wide spectrum in the region of 300 nm to 400 nm. Light having a single emission spectrum is light having a peak (i.e., the maximum peak wavelength) in the range of 300 nm to 400 nm, preferably 350 nm to 380 nm. As a light source that irradiates such light, ultraviolet light-emitting semiconductor element light sources such as ultraviolet light-emitting diodes (ultraviolet LEDs), ultraviolet light-emitting semiconductor lasers, and the like can be exemplified.

[0113] As a light source that irradiates light having a plurality of emission spectra, lamps such as metal halide lamps, xenon lamps, carbon arc lamps, chemical lamps, sodium lamps, low-pressure mercury lamps, high-pressure mercury lamps, super-high-pressure mercury lamps, and the like, gas lasers such as nitrogen gas lasers, liquid lasers of organic dye solutions, solid-state lasers containing rare earth ions in inorganic single crystals, and the like can be exemplified.

[0114] In the case where the above light has a peak in a wavelength region shorter than 300 nm in the emission spectrum, or in the case where a wavelength having a radiation intensity of 5% or more of the maximum peak wavelength in the above emission spectrum exists in a wavelength region shorter than 300 nm (for example, in the case where the emission spectrum is broadened over a wide wavelength region), and in the case where a substrate having transparency to a wavelength shorter than 300 nm, such as a quartz wafer, is used as the support, it is preferable to remove the light in the wavelength region shorter than 300 nm by an optical filter in terms of obtaining a sufficient cured product. Thereby, the radiation intensity of each wavelength in the wavelength region shorter than 300 nm is 5% or less, preferably 1% or less, more preferably 0.1% or less, and further preferably 0% of the radiation intensity of the maximum peak wavelength. Note that, in the case where a plurality of peaks exist in the wavelength region from 300 nm to 400 nm in the emission spectrum, the peak wavelength showing the largest absorbance is set as the maximum peak wavelength. The optical filter is not particularly limited as long as it is an optical filter that removes the light in the wavelength shorter than 300 nm, and a publicly known device can be used. For example, a 365 nm band-pass filter or the like can be used. Note that, the irradiance and the spectral distribution of the ultraviolet light can be measured using a spectroradiometer, such as USR-45D (Ushio Denki).

[0115] The light irradiation device is not particularly limited, but for example, a point irradiation device, a surface irradiation device, a line irradiation device, a conveyer belt irradiation device, or the like can be used.

[0116] The light irradiation time when the light-curable silicone resin composition of the present application is cured also varies depending on the irradiance, and thus cannot be determined generally, but for example, if the irradiance is adjusted so as to be 1 to 300 seconds, preferably 10 to 200 seconds, and more preferably 30 to 150 seconds, the irradiation time is also appropriately short, and there is no particular problem in the operation process. In addition, the light-curable silicone resin composition subjected to light irradiation forms a gel after 1 to 120 minutes of irradiation, particularly after 5 to 60 minutes of irradiation. Note that, in the present application, the formation of a gel means a state where the curing reaction of the light-curable silicone resin composition is partially performed, and the composition loses fluidity.

[0117] [Step (c)]

[0118] The step (c) is a step of grinding or polishing the non-circuit formation surface of the wafer temporarily bonded to the support, that is, a step of grinding the wafer back surface side of the wafer laminate obtained by the above step to thin the wafer. The grinding processing method of the wafer back surface is not particularly limited, and a publicly known grinding method is adopted. It is preferable to perform grinding while cooling by pouring water on the wafer and the grindstone (diamond or the like). As a device for grinding the wafer back surface, for example, DAG-810 (trade name) manufactured by DISCO Corporation or the like can be cited. Alternatively, the wafer back surface side can be subjected to chemical mechanical polishing (CMP).

[0119] [Step (d)]

[0120] The step (d) is a step of processing the non-circuit formation surface of the wafer laminate whose non-circuit formation surface has been ground by the step (c). That is, it is a step of processing the non-circuit formation surface of the wafer of the wafer laminate thinned by back surface grinding. This step includes various processes used at the wafer level. For example, electrode formation, metal wiring formation, protective film formation, and the like can be cited. More specifically, publicly known processes such as metal sputtering for forming an electrode or the like, wet etching for etching a metal sputtered layer, coating of resist for making a mask for metal wiring formation, pattern formation by exposure and development, stripping of resist, dry etching, formation of metal plating, silicon etching for forming a TSV, oxide film formation on a silicon surface, and the like can be cited.

[0121] [Step (e)]

[0122] The step (e) is a step of peeling the wafer on which processing has been performed by the step (d) from the support, that is, a step of peeling the wafer from the support after various processing has been performed on the thinned wafer. As this peeling step, it is generally performed under relatively mild conditions at room temperature to about 60°C. As the peeling method, a method in which one of the wafer or the support of the wafer laminate is horizontally fixed, and the other is pulled up at a certain angle from the horizontal direction; a method in which the wafer laminate is previously immersed in a solvent, the temporary bonding material layer is swelled, and then the same peeling as described above is performed; and a method in which a protective film is attached to the ground surface of the ground wafer, and the wafer and the protective film are peeled from the wafer laminate in a peeling manner, and the like can be cited. In the case where the peeling step is performed using these peeling methods, it is generally performed at room temperature.

[0123] Further, the step (e) preferably includes:

[0124] (e1) a step of attaching a dicing tape to the wafer surface of the wafer on which processing has been performed,

[0125] (e2) a step of vacuum-adsorbing the dicing tape surface to an adsorption surface, and

[0126] (e3) a process of peeling the support from the wafer on which the processing has been performed by peeling off, when the temperature of the adsorption surface is in the range of 10 to 1000C.

[0127] Thus, the support can be easily peeled from the wafer on which the processing has been performed, and the subsequent cutting process can be easily performed.

[0128] Further, after the process (e),

[0129] The process (f) of removing the temporary adhesive layer remaining on the circuit formation surface of the peeled wafer is preferably performed. A part of the temporary adhesive layer sometimes remains on the circuit formation surface of the wafer peeled from the support by the process (e), and the removal of the temporary adhesive layer can be performed by, for example, cleaning the wafer.

[0130] In the process (f), any cleaning liquid which 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 two or more kinds can be used in combination.

[0131] Further, in the case where the temporary adhesive layer is difficult to remove, an alkali or an acid can be added to the above cleaning liquid. As the alkali, amine such as ethanolamine, diethanolamine, triethanolamine, triethylamine, and ammonia; and ammonium salt such as tetramethylammonium hydroxide can be used. As the acid, organic acid such as acetic acid, oxalic acid, benzenesulfonic acid, and dodecylbenzenesulfonic acid can be used. The amount of the alkali or the acid to be added is preferably an amount in which the concentration in the cleaning liquid becomes 0.01 to 10 mass%, and more preferably 0.1 to 5 mass%. Further, in order to improve the removal of the residue, a conventional surfactant can be added. Further, SPIS-TA-CLEANER series (manufactured by Shin-Etsu Chemical Co., Ltd.) available as a wafer cleaner can also be suitably used.

[0132] As the cleaning method of the wafer, a method of cleaning using the above cleaning liquid with a stirrer, a method of cleaning by spraying a spray, and a method of dipping in a cleaning liquid tank can be listed. The temperature at the time of cleaning is preferably 10 to 80°C, and more preferably 15 to 65°C. If necessary, after dissolving the temporary adhesive layer with these cleaning liquids, a final rinsing with water or alcohol and a drying treatment can be performed.

[0133] As the second mode of the method of manufacturing a thin wafer of the present application, the processes of (a2) and (b2) shown below are exemplified. The processes of (b2) and (c) to (e), preferably (c) to (f), which are the processes subsequent to (a2), are the same as those of the first mode described above.

[0134] [Process (a2)]

[0135] Process (a2) is a process of forming a layer of the photo-irradiated photocurable silicone resin composition on the wafer and / or the support.

[0136] Unlike the first method in which the wafer and the support are joined and then photo-irradiated, by photo-irradiating the photocurable silicone resin composition before joining, the photo-irradiation process through the support is not required, and as a result, the support does not need to be light-transmissive. Therefore, according to this method, in the above-described application examples of the support, a non-light-transmissive substrate such as silicon, aluminum, SUS, copper, germanium, gallium-arsenic, gallium-phosphorus, gallium-arsenic-aluminum, and the like can also be used as the support. In addition, according to this method, the influence of the curing hindrance from the wafer can also be reduced, and thus the application range of the wafer can also be expanded.

[0137] As for the coating of the photo-irradiated photocurable silicone resin composition, any one of [1] the wafer, [2] the support, and [3] both sides of the wafer and the support can be used.

[0138] As for the method of photo-irradiating the photocurable silicone resin composition before joining, a method in which the composition is photo-irradiated while being coated on the wafer and / or the support, a method in which the entire composition is photo-irradiated and then coated on the wafer and / or the support, a method in which the composition is coated on the wafer and / or the support and then photo-irradiated, and the like can be exemplified, but there is no particular limitation, and the method can be appropriately selected in view of the workability. In addition, as for the kind of active light in the photo-irradiation, the ultraviolet irradiation amount (illuminance), the light source, the emission spectrum, the photo-irradiation device, and the photo-irradiation time, the methods listed in [Process (b1)] of the first method can be used.

[0139] The forming method of the first and second temporary adhesive layers can be performed in the same manner as the first method, and a film can be formed on the wafer and / or the support or the corresponding composition or solution thereof by a method such as spin coating, roll coating, and the like. In the case of using as a solution, after spin coating, pre-baking is performed at a temperature of 20 to 200°C, preferably 30 to 150°C, according to the volatilization conditions of the solvent, and then used.

[0140] [Process (b2)]

[0141] Process (b2) is a process of joining the wafer with the circuit formed with the layer of the photocurable silicone resin composition manufactured by process (a2) and / or the support under vacuum. At this time, by uniformly pressing the substrate at a temperature in the range of preferably 0 to 200°C, more preferably 20 to 100°C, under this temperature and reduced pressure (vacuum), a wafer processing body (laminated substrate) in which the wafer is joined to the support is formed. Here, as the wafer bonding device, the same device as in the first method can be used.

[0142] Example

[0143] The following Preparation Examples, Comparative Preparation Examples, Examples, and Comparative Examples more specifically illustrate the present application, but the present application is not limited to these Examples. It should be noted that the viscosity is a measured value at 25°C using a TVB-10M-type rotational viscometer (manufactured by Tokimec, Inc.).

[0144] [1] Preparation of photocurable silicone resin solution

[0145] [Preparation Example 1]

[0146] To a solution consisting of dimethylpolysiloxane having 2.5 mole% of vinyl groups in the side chain of the molecule, 100 parts by mass, and toluene, 200 parts by mass, was added: a solution consisting of vinylmethylpolysiloxane having 50 mole% of SiO 4 / 2 units (Q units), 48 mole% of (CH3)3SiO 1 / 2 units (M units), and 2 mole% of (CH2=CH)3SiO 1 / 2 units (Vi units), 50 parts by mass, and toluene, 100 parts by mass, a solution consisting of organohydrogenpolysiloxane represented by the following formula (M-1), 230 parts by mass, a 30 mass% toluene solution having a viscosity (25°C) of 30,000 mPa-s, dimethylpolysiloxane having both ends of the molecular chain blocked with trimethylsiloxy groups, 50 parts by mass, and toluene, 120 parts by mass, and 1-ethynylcyclohexanol, 0.6 parts by mass, were mixed. Further, a photoactive hydrosilylation reaction catalyst; a toluene solution of (methylcyclopentadienyl)trimethylplatinum(IV) (platinum concentration 1.0 mass%), 0.4 parts by mass, was added thereto, filtered using a 0.2-μm membrane filter, to prepare a photocurable silicone resin solution Al. The viscosity of the resin solution Al at 25°C was 230 mPa-s.

[0147] [Chemical 2]

[0148]

[0149] [Preparation Example 2]

[0150] To a solution consisting of dimethylpolysiloxane having 2.5 mole% of vinyl groups in the side chain of the molecule, 100 parts by mass, and toluene, 200 parts by mass, was added: a solution consisting of vinylmethylpolysiloxane having 2.5 mole% of vinyl groups in the side chain of the molecule, 100 parts by mass, and toluene, 200 parts by mass, was added: a solution consisting of vinylmethylpolysiloxane having 50 mole% of SiO 4 / 2 units (Q units), 48 mole% of (CH3)3SiO 1 / 2 units (M units), and 2 mole% of (CH2=CH)3SiO 1 / 2A solution of a dimethylpolysiloxane having a viscosity (25°C) of 1000 mPa-s of a 30 mass% toluene solution, both terminals of the molecular chain of which were capped with trimethylsiloxy groups, 30 parts by mass, and 1-ethynylcyclohexanol 0.6 parts by mass were mixed. Further, a photoreactive hydrosilylation reaction catalyst; a toluene solution of (methylcyclopentadienyl)trimethylplatinum (IV) (platinum concentration 1.0 mass%) 0.4 parts by mass, was added thereto, filtered using a 0.2 μm membrane filter, to prepare a photocurable silicone resin solution A2. The viscosity of the resin solution A2 at 25°C was 100 mPa-s.

[0151] [Preparation Example 3]

[0152] To a solution of a dimethylpolysiloxane having 2.5 mole% of vinyl groups at both terminals and side chains, Mn 30,000, 100 parts by mass, and toluene 200 parts by mass, was added: an organohydrogenpolysiloxane represented by the formula (M-1), Mn 2800, 180 parts by mass, a 30 mass% toluene solution, a dimethylpolysiloxane having a viscosity (25°C) of 1000 mPa-s of a 30 mass% toluene solution, both terminals of the molecular chain of which were capped with trimethylsiloxy groups, 30 parts by mass, and 1-ethynylcyclohexanol 0.6 parts by mass were mixed. Further, a photoreactive hydrosilylation reaction catalyst; a toluene solution of (methylcyclopentadienyl)trimethylplatinum (IV) (platinum concentration 1.0 mass%) 0.4 parts by mass, was added thereto, filtered using a 0.2 μm membrane filter, to prepare a photocurable silicone resin solution A2. The viscosity of the resin solution A2 at 25°C was 100 mPa-s. 4 / 2 a unit (Q unit), 48 mole% of (CH3)3SiO 1 / 2 a unit (M unit), and 2 mole% of (CH2=CH)3SiO 1 / 2 A solution of a dimethylpolysiloxane having a viscosity (25°C) of 1000 mPa-s of a 30 mass% toluene solution, both terminals of the molecular chain of which were capped with trimethylsiloxy groups, 30 parts by mass, and 1-ethynylcyclohexanol 0.6 parts by mass were mixed. Further, a photoreactive hydrosilylation reaction catalyst; a toluene solution of (methylcyclopentadienyl)trimethylplatinum (IV) (platinum concentration 1.0 mass%) 0.4 parts by mass, was added thereto, filtered using a 0.2 μm membrane filter, to prepare a photocurable silicone resin solution A2. The viscosity of the resin solution A2 at 25°C was 100 mPa-s.

[0153] [Preparation Example 4]

[0154] To a solution of a dimethylpolysiloxane having 2.5 mole% of vinyl groups at both terminals and side chains, Mn 30,000, 100 parts by mass, and toluene 200 parts by mass, was added: an organohydrogenpolysiloxane represented by the formula (M-1), Mn 2800, 180 parts by mass, a 30 mass% toluene solution, a dimethylpolysiloxane having a viscosity (25°C) of 1000 mPa-s of a 30 mass% toluene solution, both terminals of the molecular chain of which were capped with trimethylsiloxy groups, 30 parts by mass, and 1-ethynylcyclohexanol 0.6 parts by mass were mixed. Further, a photoreactive hydrosilylation reaction catalyst; a toluene solution of (methylcyclopentadienyl)trimethylplatinum (IV) (platinum concentration 1.0 mass%) 0.4 parts by mass, was added thereto, filtered using a 0.2 μm membrane filter, to prepare a photocurable silicone resin solution A2. The viscosity of the resin solution A2 at 25°C was 100 mPa-s. 4 / 2 a unit (Q unit), 48 mole% of (CH3)3SiO 1 / 2 a unit (M unit), and 2 mole% of (CH2=CH)3SiO1 / 2 A solution consisting of a dimethylpolysiloxane having a Mn of 7,000 and consisting of a vinylmethylpolysiloxane unit (Vi unit) 200 parts by mass and toluene 400 parts by mass, an organohydrogenpolysiloxane represented by formula (M-1) having a Mn of 2,800 430 parts by mass, a solution consisting of a dimethylpolysiloxane having both terminals of the molecular chain capped with trimethylsiloxy groups and having a viscosity (25°C) of 30% by mass toluene solution of 30,000 mPa-s 100 parts by mass and toluene 120 parts by mass, and 1-ethynylcyclohexanol 1.2 parts by mass were mixed. Further, a photoactive hydrosilylation reaction catalyst; a toluene solution of (methylcyclopentadienyl)trimethylplatinum (IV) (platinum concentration 1.0% by mass) 0.8 parts by mass was added thereto, filtered using a 0.2 μm membrane filter, to prepare a photocurable silicone resin solution A4. The viscosity of the resin solution A4 at 25°C was 120 mPa-s.

[0155] [Preparation Example 5]

[0156] To a solution consisting of a dimethylpolysiloxane having a Mn of 30,000 and having 2.5% by mole of vinyl groups in the side chains of the molecules 70 parts by mass, a dimethylpolysiloxane having a Mn of 60,000 and having 0.15% by mole of vinyl groups at both terminal chains 30 parts by mass, and toluene 200 parts by mass, were added: an organohydrogenpolysiloxane represented by formula (M-1) having a Mn of 2,800 430 parts by mass, a solution consisting of a dimethylpolysiloxane having both terminals of the molecular chain capped with trimethylsiloxy groups and having a viscosity (25°C) of 30% by mass toluene solution of 30,000 mPa-s 100 parts by mass, and toluene 120 parts by mass, and 1-ethynylcyclohexanol 1.2 parts by mass. Further, a photoactive hydrosilylation reaction catalyst; a toluene solution of (methylcyclopentadienyl)trimethylplatinum (IV) (platinum concentration 1.0% by mass) 0.8 parts by mass was added thereto, filtered using a 0.2 μm membrane filter, to prepare a photocurable silicone resin solution A4. The viscosity of the resin solution A4 at 25°C was 120 mPa-s. 4 / 2 a Q unit, a (CH3)3SiO 1 / 2 a M unit, and a (CH2=CH)3SiO 1 / 2 A solution consisting of a dimethylpolysiloxane having a Mn of 7,000 and consisting of a vinylmethylpolysiloxane unit (Vi unit) 200 parts by mass and toluene 400 parts by mass, an organohydrogenpolysiloxane represented by formula (M-1) having a Mn of 2,800 430 parts by mass, a solution consisting of a dimethylpolysiloxane having both terminals of the molecular chain capped with trimethylsiloxy groups and having a viscosity (25°C) of 30% by mass toluene solution of 30,000 mPa-s 100 parts by mass and toluene 120 parts by mass, and 1-ethynylcyclohexanol 1.2 parts by mass were mixed. Further, a photoactive hydrosilylation reaction catalyst; a toluene solution of (methylcyclopentadienyl)trimethylplatinum (IV) (platinum concentration 1.0% by mass) 0.8 parts by mass was added thereto, filtered using a 0.2 μm membrane filter, to prepare a photocurable silicone resin solution A4. The viscosity of the resin solution A4 at 25°C was 120 mPa-s.

[0157] [Preparation Example 6]

[0158] To a solution consisting of a dimethylpolysiloxane having a Mn of 30,000 and having 2.5% by mole of vinyl groups in the side chains of the molecules 70 parts by mass, a dimethylpolysiloxane having a Mn of 60,000 and having 0.15% by mole of vinyl groups at both terminal chains 30 parts by mass, and toluene 200 parts by mass, were added: an organohydrogenpolysiloxane represented by formula (M-1) having a Mn of 2,800 430 parts by mass, a solution consisting of a dimethylpolysiloxane having both terminals of the molecular chain capped with trimethylsiloxy groups and having a viscosity (25°C) of 30% by mass toluene solution of 30,000 mPa-s 100 parts by mass, and toluene 120 parts by mass, and 1-ethynylcyclohexanol 1.2 parts by mass. Further, a photoactive hydrosilylation reaction catalyst; a toluene solution of (methylcyclopentadienyl)trimethylplatinum (IV) (platinum concentration 1.0% by mass) 0.8 parts by mass was added thereto, filtered using a 0.2 μm membrane filter, to prepare a photocurable silicone resin solution A4. The viscosity of the resin solution A4 at 25°C was 120 mPa-s. 4 / 2units (Q units), 48 mole% of (CH3)3SiO 1 / 2 units (M units), and 2 mole% of (CH2=CH)3SiO 1 / 2 units (Vi units), 200 parts by mass of a vinylmethylpolysiloxane having an Mn of 7,000, and 400 parts by mass of toluene, 380 parts by mass of an organohydrogenpolysiloxane represented by formula (M-1) having an Mn of 2,800, 150 parts by mass of a dimethylpolysiloxane having a viscosity (25°C) of 1,000 mPa-s as a 30 mass% toluene solution, both terminals of the molecular chain of which are capped with trimethylsiloxy groups, and 1.2 parts by mass of 1-ethynylcyclohexanol were mixed. Further, a photoactive hydrosilylation reaction catalyst; a 2-(2-butoxyethoxy)ethyl acetate solution of bis(2,4- hexanedionato)platinum(II) (platinum concentration 0.5 mass%) 1.6 mass% was added thereto, filtered using a 0.2 μm membrane filter, and a photocurable silicone resin solution A7 was prepared. The viscosity of the resin solution A7 at 25°C was 80 mPa-s.

[0159] [Preparation Example 7]

[0160] To a solution composed of a dimethylpolysiloxane having 2.5 mole% of vinyl groups in the side chain of the molecule, 70 parts by mass, an Mn of 30,000, a dimethylpolysiloxane having 0.15 mole% of vinyl groups at both terminal chains, 30 parts by mass, and an Mn of 60,000, and 200 parts by mass of toluene, the following were added: an SiO 4 / 2 units (Q units), 48 mole% of (CH3)3SiO 1 / 2 units (M units), and 2 mole% of (CH2=CH)3SiO 1 / 2 units (Vi units), 200 parts by mass of a vinylmethylpolysiloxane having an Mn of 7,000, and 400 parts by mass of toluene, 380 parts by mass of an organohydrogenpolysiloxane represented by formula (M-1) having an Mn of 2,800, 150 parts by mass of a dimethylpolysiloxane having a viscosity (25°C) of 1,000 mPa-s as a 30 mass% toluene solution, both terminals of the molecular chain of which are capped with trimethylsiloxy groups, and 1.2 parts by mass of 1-ethynylcyclohexanol were mixed. Further, a photoactive hydrosilylation reaction catalyst; a 2-(2-butoxyethoxy)ethyl acetate solution of bis(2,4- hexanedionato)platinum(II) (platinum concentration 0.5 mass%) 1.6 mass% was added thereto, filtered using a 0.2 μm membrane filter, and a photocurable silicone resin solution A7 was prepared. The viscosity of the resin solution A7 at 25°C was 80 mPa-s.

[0161] [Comparative Preparation Example 1]

[0162] A thermocurable silicone resin solution CA1 was produced in the same manner as in Production Example 1 except that 0.4 parts by mass of a toluene solution of a photoactive hydrosilylation reaction catalyst; (methylcyclopentadienyl)trimethylplatinum(IV) (platinum concentration 1.0 mass%) was changed to 0.4 parts by mass of a thermally active hydrosilylation reaction catalyst; CAT-PL-5 (manufactured by Shin-Etsu Chemical Co., Ltd., platinum concentration 1.0 mass%) and that a solution composed of dimethylpolysiloxane 50 parts by mass having both terminals of the molecular chain capped with trimethylsiloxy groups and toluene 120 parts by mass was not added. The viscosity of the resin solution CA1 at 25°C was 230 mPa-s.

[0163] [Comparative Production Example 2]

[0164] A photo-curable silicone resin solution CA2 was produced in the same manner as in Production Example 1 except that a solution composed of dimethylpolysiloxane 50 parts by mass having both terminals of the molecular chain capped with trimethylsiloxy groups and toluene 120 parts by mass was not added. The viscosity of the resin solution CA2 at 25°C was 150 mPa-s.

[0165] [Comparative Production Example 3]

[0166] A photo-curable silicone resin solution CA3 was produced in the same manner as in Production Example 2 except that dimethylpolysiloxane 30 parts by mass having both terminals of the molecular chain capped with trimethylsiloxy groups was not added. The viscosity of the resin solution CA3 at 25°C was 180 mPa-s.

[0167] [Comparative Production Example 4]

[0168] A photo-curable silicone resin solution CA4 was obtained in the same manner as in Production Example 1 except that dimethylpolysiloxane 50 parts by mass having both terminals of the molecular chain capped with trimethylsiloxy groups was changed to polysiloxane (viscosity (25°C) of a 30 mass% toluene solution: 33000 mPa-s) represented by the following formula (M-2) containing an epoxy group in the side chain 50 parts by mass. The viscosity of the resin solution CA4 at 25°C was 260 mPa-s.

[0169] [Production Example 3]

[0170]

[0171] [Comparative Production Example 5]

[0172] A photo-curable silicone resin solution CA5 was obtained in the same manner as in Production Example 2 except that dimethylpolysiloxane 30 parts by mass having both terminals of the molecular chain capped with trimethylsiloxy groups was changed to polysiloxane (viscosity (25°C) of a 30 mass% toluene solution: 2500 mPa-s) represented by the following formula (M-3) containing a trimethoxysilyl group in the side chain 30 parts by mass. The viscosity of the resin solution CA5 at 25°C was 190 mPa-s.

[0173] [Chemical Formula 4]

[0174]

[0175] [2] Manufacture of wafer laminate and evaluation thereof

[0176] [Examples 1 to 7 and Comparative Examples 1 to 5]

[0177] On a silicon wafer (thickness: 725 μm) of 200 mm in diameter on which copper pillars of 10 μm in height and 40 μm in diameter were formed on the entire front surface, spin-coat curable silicone resin solutions Al to A7, CA1 to CA5, respectively, and heat at 100°C for 2 minutes using a hot plate to form a temporary adhesive layer having a film thickness shown in Table 1 below on the wafer bump formation surface. Using a wafer bonding apparatus EVG520IS of EVG, the silicon wafer having the temporary adhesive layer and a glass plate of 200 mm in diameter (thickness: 500 μm) as a support were vacuum-bonded at 25°C, 10 mbar or less under a load of 5 kN, respectively, to bring the temporary adhesive layer and the glass plate together. Thereafter, the curable silicone resin composition layer was subjected to light irradiation using a surface irradiation type UV-LED (wavelength 365 nm) irradiator under the conditions shown in Table 1 to manufacture a wafer laminate. In addition, for the sample using the thermally curable silicone resin solution CA1, a wafer laminate was manufactured by heating on a hot plate under the conditions shown in Table 1. -3 mbar or less under a load of 5 kN, respectively, to bring the temporary adhesive layer and the glass plate together. Thereafter, the curable silicone resin composition layer was subjected to light irradiation using a surface irradiation type UV-LED (wavelength 365 nm) irradiator under the conditions shown in Table 1 to manufacture a wafer laminate. In addition, for the sample using the thermally curable silicone resin solution CA1, a wafer laminate was manufactured by heating on a hot plate under the conditions shown in Table 1.

[0178] Thereafter, the obtained wafer laminate was subjected to the following tests. The results thereof are collectively shown in Table 1. In addition, the tests were performed by the following methods.

[0179] (1) Wafer warpage test

[0180] In the manufacture of the wafer laminate described above, the wafer warpage state at the time of curing of the temporary adhesive layer was confirmed by visual observation. A case where there was no warpage at all was evaluated as "O", and a case where warpage occurred was evaluated as "X".

[0181] (2) Adhesiveness test

[0182] After the wafer laminate described above was heated at 180°C for 1 hour using an oven and cooled to room temperature, the adhesion state of the wafer interface was confirmed by visual observation, a case where no abnormality such as a bubble occurred at the interface was evaluated as good and shown as "O", and a case where an abnormality occurred was evaluated as poor and shown as "X".

[0183] (3) Back surface grinding resistance test

[0184] Using the aforementioned wafer stack, the back side of the silicon wafer was ground using a diamond grinding wheel on a grinding machine (DAG-810 manufactured by DISAK Corporation). After grinding to a substrate thickness of 50 μm, an optical microscope (100x) was used to inspect for abnormalities such as cracks and peeling. Cases without abnormalities were rated as good and marked "○", while cases with abnormalities were rated as bad and marked "×".

[0185] (4) CVD tolerance test

[0186] After the back-side grinding tolerance test (3), the wafer stack was introduced into the CVD apparatus for a 2μm SiO2 film formation experiment. Visual inspection was conducted to check for any abnormalities. Cases without abnormalities were rated as good and marked "○", while cases with abnormalities such as porosity, wafer expansion, or wafer breakage were rated as bad and marked "×". The conditions for the CVD tolerance test are as follows:

[0187] Device Name: Plasma CVD manufactured by SAMKO Corporation, PD270STL

[0188] RF500W, internal pressure 40Pa

[0189] TEOS (Tetraethyl Orthosilicate): O2 = 20 sccm: 680 sccm

[0190] (5) Peel test

[0191] Regarding the peelability of the substrate, firstly, a cutting tape (ELPUB-3083D manufactured by Nitto Denko Corporation) was applied to the wafer side of the wafer stack after the (4) CVD tolerance test using a cutting frame, and the cutting tape side was placed on the adsorption plate by vacuum adsorption. Then, at room temperature, a glass substrate was peeled off by picking up a piece of glass with tweezers. Cases in which peeling was possible without breaking the 50μm thick wafer were marked as "○", and cases in which abnormalities such as breakage occurred were evaluated as defective and marked as "×".

[0192] (6) Cleaning and removal test

[0193] After the peel test (5), wafers with a diameter of 200 mm (exposed to CVD tolerance test conditions) were placed on a spin coater with the peel side facing upwards, using dicing tape loaded onto the cutting frame. SPIS-TA-CLEANER 25 (manufactured by Shin-Etsu Chemical Co., Ltd.) was sprayed as a cleaning solvent for 5 minutes, followed by rinsing with isopropyl alcohol (IPA) while rotating the wafer. Afterwards, the appearance was observed, and the presence of any adhesive residue was visually inspected. Samples with no visible resin residue were rated as good and marked "○", while samples with visible resin residue were rated as poor and marked "×".

[0194] (7) Peeling force test of peeling

[0195] On a silicon wafer (thickness: 725 μm) having a diameter of 200 mm, the curable silicone resin solutions Al to A7 and CA1 to CA5 were spin-coated, respectively, and the silicone resin layers were formed in the film thicknesses shown in Table 1 by heating at 100°C for 2 minutes using a hot plate. Thereafter, the curable silicone resin composition layers were subjected to light irradiation using a surface irradiation type UV-LED (wavelength 365 nm) irradiator under the conditions shown in Table 1, and the temporary adhesive layers were cured. In addition, for the sample using the thermally curable silicone resin solution CA1, the temporary adhesive layer was cured by heating on a hot plate under the conditions shown in Table 1.

[0196] Thereafter, 5 pieces of polyimide tape having a length of 150 mm and a width of 25 mm were attached to the silicone resin layer on the above wafer, and the temporary adhesive layer was removed from the portions not attached with the tape. Using an AUTOGRAPH (AG-1) manufactured by Shimadzu Corporation, the silicone resin layer was peeled off at 180° at a speed of 300 mm / minute from one end of the tape at 25°C, and the average (120 mm x 5 times) of the force applied at this time was taken as the peeling force of the silicone resin layer.

[0197] (8) Storage modulus measurement

[0198] On a silicon substrate, the curable silicone resin solutions Al to A7 and CA1 to CA5 were spin-coated, respectively, and the silicone resin layers were formed on the silicon substrate in the film thicknesses shown in Table 1 by heating at 100°C for 2 minutes using a hot plate. Thereafter, the curable silicone resin composition layers were subjected to light irradiation using a surface irradiation type UV-LED (wavelength 365 nm) irradiator under the conditions shown in Table 1, and the temporary adhesive layers were cured. On the other hand, for the sample using the thermally curable silicone resin solution CA1, the temporary adhesive layer was cured by heating on a hot plate under the conditions shown in Table 1.

[0199] Using an ARES G2 manufactured by TA Instruments, Inc., the elastic modulus was measured at 25°C at 1 Hz in a state in which the obtained silicon substrate including the temporary adhesive layer was sandwiched using a 25 mm aluminum plate with a load of 50 gf applied to the temporary adhesive layer, and the value of the obtained elastic modulus was taken as the storage modulus of the silicone resin layer.

[0200] [Table 1]

[0201]

[0202] [Table 2]

[0203]

[0204] As shown in Table 1, the wafer laminates of Examples 1 to 7 including the temporary adhesive layer of the present application could be cured at a lower temperature and in a short time, and wafer warpage at the time of curing was also reduced. In addition, it was confirmed that sufficient processing durability was obtained, and the peelability was also excellent, and further, the cleaning removability after peeling was also good. On the other hand, as shown in Table 2, in Comparative Examples 1 and 2 in which a thermally active catalyst was used, it was confirmed that curing was insufficient due to insufficient heating, and wafer warpage at the time of curing. In addition, in Comparative Examples 3 and 4 in which no functional organopolysiloxane was used, and Comparative Examples 5 and 6 in which a functional organopolysiloxane was included, the wafer with a circuit and the support were strongly bonded, and as a result, wafer breakage occurred in the peeling process, and further, peeling was not possible.

[0205] [Example 8]

[0206] The photocurable silicone resin solution Al was subjected to light irradiation under the conditions shown in Table 2 using a surface irradiation type UV-LED (wavelength 365 nm) irradiator, and then, spin-coated on a silicon wafer (Si wafer with a circuit, thickness: 725 μm) of 200 mm in diameter on which copper pillars of 10 μm in height and 40 μm in diameter were formed on the entire front surface, and a temporary adhesive layer was formed on the wafer bump forming surface at a film thickness shown in Table 2 below using a hot plate at 100°C for 2 minutes. A silicon wafer (Si wafer, thickness: 770 μm) of 200 mm in diameter was used as a support, and the Si wafer with a temporary adhesive layer and the Si wafer of the support were vacuum-bonded at 25°C, 10 mbar or less at a load of 5 kN each using a wafer bonding apparatus EVG520IS of EVG Corporation, and the temporary adhesive layer was brought together with the Si wafer, and thus a wafer laminate was produced. -3 mbar or less at a load of 5 kN each using a wafer bonding apparatus EVG520IS of EVG Corporation, and the temporary adhesive layer was brought together with the Si wafer, and thus a wafer laminate was produced.

[0207] [Example 9]

[0208] A wafer laminate was produced similarly to the above Example 8 except that the object to which the light-irradiated photocurable silicone resin solution Al was applied was changed from the Si wafer with a circuit to the Si wafer of the support.

[0209] [Example 10]

[0210] A wafer laminate was produced similarly to the above Example 8 except that the object to which the light-irradiated photocurable silicone resin solution Al was applied was changed from the Si wafer with a circuit to both the Si wafer with a circuit and the Si wafer of the support.

[0211] [Example 11]

[0212] A wafer laminate was produced similarly to the above Example 8 except that the photocurable silicone resin solution used was changed from Al to A6.

[0213] [Example 12]

[0214] A wafer laminate was produced in the same manner as in the above-mentioned Example 9, except that the photocurable silicone resin solution to be used was changed from Al to A6.

[0215] [Example 13]

[0216] A wafer laminate was produced in the same manner as in the above-mentioned Example 10, except that the photocurable silicone resin solution to be used was changed from Al to A6.

[0217] In the above-mentioned Examples 8 to 13, the wafer laminates obtained were subjected to the same tests as the above-mentioned (1) wafer warpage test to (6) cleaning removability test. The results are shown in Table 3.

[0218] In addition, as for (7) peeling force test of peeling and (8) storage modulus measurement, a photocurable silicone resin solution subjected to light irradiation in advance was spin-coated on a silicon wafer (Si wafer, thickness: 770 μm) having a diameter of 200 mm, and the silicone resin layer was cured by heating at 100°C for 5 minutes using a hot plate, to prepare a test sample. Thereafter, the peeling force test of peeling and the elastic modulus measurement test were carried out in the same manner as above, and the results are shown in Table 3.

[0219] [Table 3]

[0220]

[0221] As shown in Table 3, it was confirmed that in the manufacturing method of a thin wafer of the present application, in the case where a silicone resin solution subjected to light irradiation in advance was applied and bonded, wafer processability equivalent to the case where light irradiation was carried out after application and bonding was also able to be obtained. In this case, since light irradiation through the support was not required, it is considered that the range of application of the support is expanded, and in addition, advantages such as avoidance of light damage to the device wafer can be obtained.

Claims

1. A temporary adhesive for temporarily bonding a wafer to a support during wafer processing, comprising a photocurable silicone resin composition, wherein the photocurable silicone resin composition comprises: (A) Organopolysiloxanes having two or more alkenyl groups in one molecule, (B) Organohydrogen polysiloxanes containing two or more hydrogen atoms bonded to silicon atoms (i.e., SiH groups) in one molecule. (C) Non-functional organopolysiloxanes, and (D) Photoactive hydrosilylation catalyst, The (C) nonfunctional organopolysiloxane is an organopolysiloxane whose molecular chains are closed at both ends by trimethylsiloxy groups or dimethylphenylsiloxy groups. A 30% by mass toluene solution of the (C) nonfunctional organopolysiloxane has a viscosity of 1000–500000 mPa at 25°C. s.

2. The temporary adhesive for wafer processing according to claim 1, wherein, The photocurable silicone resin composition containing nonfunctional organopolysiloxane comprises: (A) Organopolysiloxanes having two or more alkenyl groups in one molecule: 100 parts by mass, (B) Organohydrogen polysiloxanes containing two or more hydrogen atoms bonded to silicon atoms (i.e., SiH groups) in one molecule: the amount of SiH groups in component (B) is 0.3 to 10 molar ratio relative to the total number of alkenes in component (A). (C) Non-functional organopolysiloxanes: 0.1–200 parts by weight, and (D) Photoactive hydrogen silanization catalyst: 0.1 to 5000 ppm relative to the total mass of components (A), (B) and (C) in terms of metal atomic weight.

3. The temporary adhesive for wafer processing according to claim 2, wherein, (C) The viscosity of a 30% by mass toluene solution of the nonfunctional organopolysiloxane of component (C) at 25°C is 1000–100000 mPa·s.

4. The temporary adhesive for wafer processing according to any one of claims 1 to 3, wherein, Relative to the total mass of components (A), (B) and (C), the photocurable silicone resin composition containing nonfunctional organopolysiloxane further comprises 0.001 to 10 parts by mass of a hydrogenation silanization reaction control agent as component (E).

5. The temporary adhesive for wafer processing according to any one of claims 1 to 3, wherein, After curing, the photocurable silicone resin composition containing nonfunctional organopolysiloxane has a peel force of more than 2 gf and less than 50 gf when a 25 mm wide test piece peels off a silicon substrate at 25°C at a distance of 180°.

6. The temporary adhesive for wafer processing according to any one of claims 1 to 3, wherein, After curing, the photocurable silicone resin composition containing non-functional organopolysiloxane has a storage modulus of 1000 Pa or more and 1000 MPa or less at 25°C.

7. A method for manufacturing a thin wafer using a photocurable silicone resin composition containing a nonfunctional organopolysiloxane, wherein, In the process of bonding and curing the wafer and the support through a temporary adhesive layer to form a wafer stack, namely in steps (a) and (b) below, any of the following methods are included, wherein steps (c) to (e) are common in any of the methods. (Method 1) (a1) A process of applying a composition of a temporary adhesive for wafer processing according to any one of claims 1 to 6 to the circuit-forming surface of a wafer having a circuit-forming surface on the front side and a non-circuit-forming surface on the back side, and / or the bonding surface of the support to the wafer, to perform bonding. (b1) A process of photocuring the temporary adhesive of the joined wafers. (Method 2) (a2) A step of irradiating the composition of the temporary adhesive for wafer processing according to any one of claims 1 to 6 with light. (b2) A bonding process in which the composition of the temporary adhesive for wafer processing irradiated by light in (a2) is applied to the circuit forming surface of a wafer having a circuit forming surface on the front side and a non-circuit forming surface on the back side, and / or the bonding surface of the support to the wafer. (c) The process of grinding or polishing the non-circuit forming surface of the wafer in the wafer stack. (d) A process for processing the non-circuit forming surface of the wafer. (e) The process of peeling the processed wafer described in (d) from the support.

8. A wafer stack comprising: a support, a temporary adhesive layer obtained by a temporary adhesive for wafer processing according to any one of claims 1 to 6, and a wafer having a circuit forming surface on a front side and a non-circuit forming surface on a back side, stacked thereon. The temporary adhesive layer is peelably bonded to the front side of the wafer.

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