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

Abstract

An object of the present invention is to provide a temporary adhesive for wafer processing, a wafer laminate, and a method for manufacturing a thin wafer using the same, which have sufficient substrate holding properties after bonding even in a case where a highly stepped substrate is used, have high process compatibility with a wafer rear surface grinding step, a TSV forming step, and a wafer rear surface wiring step, are easily peeled off in a peeling step even after a high-temperature and long-time thermal process is performed in the air after bonding, have excellent residue washability of a substrate after peeling, and lead to improvement of productivity of a thin wafer.SOLUTION: A temporary adhesive for a wafer processing for temporarily adhering a wafer to a support, wherein the temporary adhesive for a wafer processing comprises a curable silicone resin composition that can be cured by a hydrosilylation reaction, and the curable silicone resin composition comprises an organopolysiloxane having only one alkenyl group or only one hydrogen atom bonded to a silicon atom (SiH group) in one molecule.SELECTED DRAWING: None

Description

[Technical Field]

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

[0002] Three-dimensional semiconductor packaging is becoming essential for achieving ever-increasing density and capacity. 3D packaging technology is a semiconductor fabrication technology that thins individual semiconductor chips and then stacks them in multiple layers while connecting them with through-silicon vias (TSVs). To achieve this, a substrate with semiconductor circuits formed on it must be thinned by grinding the non-circuit-forming side (also called the "backside"), followed by the process of forming electrodes, including TSVs, on the backside. Conventionally, in the backside grinding process for silicon substrates, a backside protection tape is attached to the side opposite the grinding surface to prevent wafer damage during grinding. However, this tape uses an organic resin film as a support base, which, while flexible, lacks strength and heat resistance, making it unsuitable for the TSV formation process or the backside wiring layer formation process.

[0003] Therefore, a system has been proposed in which a semiconductor substrate is bonded to a support such as silicon or glass via an adhesive layer, thereby being able to withstand the processes of back grinding, TSV formation, and back electrode formation. The adhesive layer used to bond the substrate to the support is crucial. It must be able to bond the substrate to the support without gaps, be durable enough to withstand subsequent processes, and ultimately allow the thin wafer to be easily peeled from the support. Because this adhesive layer is peeled off last, it is also referred to as a temporary adhesive layer in this specification.

[0004] Previously known temporary adhesive layers and their peeling methods include a technique in which high-intensity light is irradiated onto an adhesive containing a light-absorbing substance to decompose the adhesive layer and thereby peel it off from the support (Patent Document 1), and a technique in which a heat-fusible hydrocarbon compound is used as the adhesive and bonding and peeling are performed in a heated, molten state (Patent Document 2). The former technique requires expensive equipment such as a laser and has problems such as a long processing time per substrate. The latter technique is simple because it is controlled only by heating, but its thermal stability at temperatures above 200°C is insufficient, limiting its range of application. Furthermore, these temporary adhesive layers are not suitable for forming a uniform film thickness on high-step substrates or for complete adhesion to the support.

[0005] Furthermore, a technology using a silicone adhesive as a temporary adhesive layer has been proposed. In this technology, an addition-curing silicone adhesive is used to adhere a substrate to a support, and when peeling, the substrate is separated from the support by immersing it in a chemical that dissolves or decomposes the silicone resin (Patent Document 3). As a result, peeling takes an extremely long time, making it difficult to apply to actual manufacturing processes. Furthermore, after peeling, it takes a long time to clean off the silicone adhesive that remains as residue on the substrate, which also poses a problem in terms of cleaning removability.

[0006] To address the above-mentioned issues, a technology using a curable silicone composition containing a non-functional polyorganosiloxane as a temporary adhesive layer has been previously known (Patent Documents 4 and 5). This composition allows a substrate and a support to be bonded via a temporary adhesive layer, thereby achieving adhesion between the substrate and the temporary adhesive layer that can withstand substrate processing. Furthermore, when the support is peeled from the substrate, the temporary adhesive layer can be selectively peeled off while remaining adhered to the support, so that almost no temporary adhesive layer remains on the substrate after peeling. This significantly improves the washability of the substrate after peeling, making it possible to satisfy both the above-mentioned issues of peelability and washability. However, depending on the type of substrate with a high step, selective peeling from between the substrate and the temporary adhesive layer may not be possible, and some of the temporary adhesive may remain on the substrate, resulting in problems such as requiring a long time to clean the residue.In addition, peeling the thinned substrate from the support after a long, high-temperature thermal process can lead to an abnormality where the substrate cracks, so an immediate solution was needed. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-64040 [Patent Document 2] Japanese Patent Application Laid-Open No. 2006-328104 [Patent Document 3] U.S. Patent No. 7,541,264 [Patent Document 4] WO2021-112070 publication [Patent Document 5] WO2021-220929 publication Summary of the Invention [Problem to be solved by the invention]

[0008] The present invention has been made in consideration of the above-mentioned problems, and aims to provide a temporary adhesive for wafer processing, a wafer laminate, and a method for manufacturing thin wafers using the same, which have sufficient substrate retention after bonding even when using a substrate with a high step difference, are highly process-compatible with the wafer backside grinding process, TSV formation process, and wafer backside wiring process, are easy to peel in the peeling process even after undergoing a high-temperature, long-term thermal process in air after bonding, and have excellent residue cleanability on the substrate after peeling, thereby leading to improved productivity of thin wafers, such as: [Means for solving the problem]

[0009] In order to solve the above problems, the present invention provides: The present invention provides a temporary adhesive for wafer processing, which is used to temporarily bond a wafer to a support, and which is made of a curable silicone resin composition that can be cured by a hydrosilylation reaction, and which is characterized in that the curable silicone resin composition contains an organopolysiloxane that has only one alkenyl group or only one hydrogen atom bonded to a silicon atom (SiH group) per molecule.

[0010] Such a curable silicone resin composition exhibits sufficient substrate retention after bonding, even when a substrate with a high level difference is used, is highly compatible with the wafer backside grinding process, TSV formation process, and wafer backside wiring process, and is easy to peel in the peeling process even after undergoing a high-temperature, long-term thermal process in air after bonding. It also exhibits excellent cleanability for removing residue from the substrate after peeling, and is particularly able to improve the heat resistance of the resin.

[0011] Furthermore, the curable silicone resin composition is (A) organopolysiloxane having two or more alkenyl groups per molecule: 100 parts by mass, (B) an organopolysiloxane having only one alkenyl group or only one hydrogen atom bonded to a silicon atom (SiH group) per molecule: 0.1 to 100 parts by mass, (C) an organohydrogenpolysiloxane containing two or more silicon-bonded hydrogen atoms (SiH groups) per molecule: in an amount such that the total of the SiH groups in components (B) and (C) relative to the total of the alkenyl groups in components (A) and (B) is in a molar ratio of 0.3 to 5; (D) non-functional organopolysiloxane: 0.1 to 200 parts by mass, and (E) Hydrosilylation reaction catalyst: 0.1 to 5,000 ppm in terms of metal atomic weight based on the total mass of components (A), (B), (C), and (D). It is preferred that the compound contains:

[0012] Such a curable silicone resin composition is preferable as a temporary adhesive for wafer processing.

[0013] In this case, it is preferable that the organopolysiloxane containing two or more alkenyl groups in one molecule of component (A) also contains at least one aryl group.

[0014] Such component (A) can be used as the curable silicone resin composition.

[0015] The non-functional organopolysiloxane of component (D) is preferably a dimethylpolysiloxane having a viscosity of 100 to 500,000 mPa·s at 25° C. in a 30% by mass toluene solution.

[0016] Such a viscosity is preferable from the viewpoints of workability of the composition, applicability to equipment, mechanical properties of the drop, peelability of the support, and the like.

[0017] Furthermore, it is preferable that the curable silicone resin composition containing the components (A) to (E) further contains a hydrosilylation reaction inhibitor as component (F) in an amount of 0.001 to 10 parts by mass, based on the total mass of the components (A), (B), and (C).

[0018] By including the component (F), thickening and gelation of the curable silicone resin composition can be prevented.

[0019] It is preferable that the organopolysiloxane contains only one alkenyl group or only one silicon-bonded hydrogen atom (SiH group) located on either a side chain or at the end of one molecule.

[0020] By including such an organopolysiloxane in the curable silicone resin composition, the heat resistance of the resin can be further improved.

[0021] The curable silicone resin composition is preferably one that can be cured by light and / or heat.

[0022] Such a curable silicone resin composition can be made into a composition that can be cured by light and / or heat through the hydrosilylation reaction of the component (E) used.

[0023] After the curable silicone resin composition is cured, it is preferable that the 180° peel strength of a 25 mm wide test piece against a silicon substrate at 25°C is 2 gf or more and 100 gf or less.

[0024] If the 180° peel force is 2 gf or more, there is no risk of the wafer slipping during wafer grinding, and if it is 100 gf or less, the wafer can be easily peeled.

[0025] After curing, the curable silicone resin composition preferably has a storage modulus at 25° C. of 1,000 Pa or more and 1,000 MPa or less.

[0026] If the storage modulus is 1,000 Pa or more, the film formed is strong and there is no risk of wafer misalignment or subsequent wafer cracking during wafer grinding. If the storage modulus is 1,000 MPa or less, deformation stress during wafer thermal processes such as CVD can be alleviated, and the film is stable even during thermal processes on the wafer.

[0027] Furthermore, the present invention provides (a) forming a wafer laminate by releasably adhering 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 described above; (b) curing the temporary adhesive; (c) grinding or polishing the non-circuit-forming surfaces of the wafers in the wafer stack; (d) processing the non-circuit-forming surface of the wafer; (e) peeling the processed wafer from the support; The present invention provides a method for manufacturing a thin wafer, comprising:

[0028] By such a method for producing a thin wafer, the temporary adhesive for wafer processing can be used to temporarily bond a wafer having semiconductor circuits and the like to a support.

[0029] Furthermore, the present invention provides a wafer laminate comprising a support, a temporary adhesive layer obtained from the above-mentioned temporary adhesive for wafer processing laminated thereon, and a wafer having a circuit-forming surface on its front side and a circuit-free surface on its back side, wherein the temporary adhesive layer is releasably adhered to the front side of the wafer.

[0030] Use of such a wafer stack can lead to improved productivity in thin wafers. [Effects of the Invention]

[0031] As described above, 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 organopolysiloxane having only one alkenyl group or only one hydrogen atom bonded to a silicon atom (SiH group) per molecule. This stabilizes the releasability of the substrate and support, making it possible to easily peel the substrate from the support, especially even when exposed to high temperatures of 200°C or higher for long periods after bonding, and also provides excellent cleanability for residues after peeling. Therefore, the method can be applied to a wide range of semiconductor film formation processes, has excellent CVD (chemical vapor deposition) resistance, and can form a temporary adhesive layer with high film thickness uniformity even on wafers with steps, making it possible to easily manufacture thin wafers that are prone to cracking. According to the method for manufacturing a thin wafer of the present invention, it is possible to easily manufacture thin wafers that have a through electrode structure or a bump connection structure. DETAILED DESCRIPTION OF THE INVENTION

[0032] As mentioned above, in the technology using a curable silicone composition for the temporary adhesive layer, depending on the type of substrate with a high step height, selective peeling from between the substrate and the temporary adhesive layer is not possible, and some of the temporary adhesive remains on the substrate, resulting in problems such as the need for a long time to clean off the residue. Furthermore, peeling the thinned substrate from the support after a long-term thermal process at high temperature can lead to an abnormality in which the substrate cracks, and therefore an immediate solution was needed.

[0033] As a result of extensive research into the above-mentioned problems, the present inventors have discovered that the use of a curable silicone resin composition containing a specific organopolysiloxane as a temporary adhesive for wafer processing can improve the heat resistance of the resin. They have also discovered that a temporary adhesive layer with high film thickness uniformity can be formed even on wafers with steps, making it possible to easily manufacture thin wafers that are prone to cracking, and have completed the present invention.

[0034] That is, the present invention provides a temporary adhesive for wafer processing, for temporarily bonding a wafer to a support, characterized in that the temporary adhesive for wafer processing comprises a curable silicone resin composition that can be cured by a hydrosilylation reaction, and the curable silicone resin composition contains an organopolysiloxane having only one alkenyl group or only one hydrogen atom bonded to a silicon atom (SiH group) per molecule.

[0035] The present invention will be described in detail below, but the present invention is not limited thereto.

[0036] [Temporary adhesive for wafer processing] The temporary adhesive for wafer processing of the present invention comprises a curable silicone resin composition containing an organopolysiloxane having only one alkenyl group or only one hydrogen atom bonded to a silicon atom (SiH group) per molecule. Because of its applicability to silicon wafers and the like having uneven surfaces, silicone resin compositions with good spin-coatability are preferably used as temporary adhesives for wafer processing.

[0037] Such a curable silicone resin composition preferably contains, for example, the following components (A) to (E): The hydrosilylation reaction catalyst of component (E) used can make the composition heat- and / or light-curable. (A) organopolysiloxane having two or more alkenyl groups per molecule: 100 parts by mass, (B) an organopolysiloxane having only one alkenyl group or only one hydrogen atom bonded to a silicon atom (SiH group) per molecule: 0.1 to 100 parts by mass, (C) an organohydrogenpolysiloxane containing two or more silicon-bonded hydrogen atoms (SiH groups) per molecule: in an amount such that the total of the SiH groups in components (B) and (C) relative to the total of the alkenyl groups in components (A) and (B) is in a molar ratio of 0.3 to 5; (D) non-functional organopolysiloxane: 0.1 to 200 parts by mass, and (E) Hydrosilylation reaction catalyst: 0.1 to 5,000 ppm in terms of metal atomic weight based on the total mass of components (A), (B), (C), and (D).

[0038] [Component (A)] Component (A) is an organopolysiloxane having two or more alkenyl groups per molecule. Component (A) includes linear or branched diorganopolysiloxanes containing two or more alkenyl groups per molecule, organopolysiloxanes containing two or more alkenyl groups and at least one aryl group per molecule, and organopolysiloxanes containing two or more alkenyl groups per molecule and having SiO 4 / 2 and organopolysiloxanes having a three-dimensional network structure with siloxane units (Q units) represented by units. Among these, diorganopolysiloxanes or organopolysiloxanes having a three-dimensional network structure with an alkenyl group content of 0.0001 to 3.0 mol / 100 g are preferred. In the present invention, the alkenyl group content refers to the number of moles of alkenyl groups contained per 100 g.

[0039] Furthermore, the component (A) is preferably an organopolysiloxane containing two or more alkenyl groups and at least one or more aryl groups in each molecule.

[0040] Such organopolysiloxanes include those represented by the following formula (A-1), (A-2), or (A-3): These may be used alone or in combination of two or more. [ka]

[0041] In formulas (A-1) to (A-3), R 1 ~R 16 are each independently a monovalent hydrocarbon group other than an aliphatic unsaturated hydrocarbon group. 1 ~X 5 are each independently an alkenyl-containing monovalent organic group.

[0042] In formula (A-1), a and b each independently represent an integer of 0 to 3. In formulas (A-1) and (A-2), c 1 , c 2 , d 1 and d 2 is 0≦c 1 ≦100, 2≦c 2 ≦100, 0≦d 1 ≦10,000 and 0≦d 2 An integer that satisfies ≦10,000, where a+b+c 1 ≧2. a, b, c 1 , c 2 , d 1 and d 2 The alkenyl group content is preferably 0.0001 to 3.0 mol / 100 g.

[0043] In formula (A-3), e is an integer of 1 to 3. 1 , f 2 and f 3 is (f 2 +f 3 ) / f 1is 0.3 to 4.0, and the alkenyl group content is 0.001 to 2.3 mol / 100 g.

[0044] The monovalent hydrocarbon group other than the aliphatic unsaturated hydrocarbon group is preferably one having 1 to 10 carbon atoms, 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. Of these, alkyl groups such as methyl or phenyl are preferred.

[0045] The alkenyl-containing monovalent organic group preferably has 2 to 10 carbon atoms, and examples thereof include alkenyl groups such as vinyl, allyl, hexenyl, and octenyl; (meth)acryloylalkyl groups such as acryloylpropyl, acryloylmethyl, and methacryloylpropyl; (meth)acryloxyalkyl groups such as acryloxypropyl, acryloxymethyl, methacryloxypropyl, and methacryloxymethyl; and alkenyl-containing monovalent hydrocarbon groups such as cyclohexenylethyl and vinyloxypropyl. Of these, vinyl is preferred from an industrial viewpoint.

[0046] In formula (A-1), a and b are each independently an integer of 0 to 3, but when a is 1 to 3, the molecular chain terminals are blocked with alkenyl groups, and the highly reactive alkenyl groups at the molecular chain terminals enable the reaction to be completed in a short time, which is preferable. Furthermore, from an industrial perspective, it is preferable for a to be 1. The alkenyl-containing diorganopolysiloxane represented by formula (A-1) or (A-2) is preferably in the form of an oil or a crude rubber.

[0047] The organopolysiloxane represented by formula (A-3) is SiO 4 / 2It contains units and has a three-dimensional network structure. In formula (A-3), e is each independently an integer of 1 to 3, but is industrially preferably 1 from the viewpoint of cost. In addition, the product of the average value of e and the alkenyl group content is preferably 0.001 to 7.0 mol / 100 g, more preferably 0.001 to 2.3 mol / 100 g. The organopolysiloxane represented by formula (A-3) may be used as a solution dissolved in an organic solvent.

[0048] The number average molecular weight (Mn) of the organopolysiloxane of component (A) is preferably 100 to 1,000,000, and more preferably 1,000 to 100,000. Mn within this range is preferable in terms of workability due to the viscosity of the composition and processability due to the storage modulus after curing. In the present invention, Mn is a value measured in terms of polystyrene equivalent by gel permeation chromatography using toluene as a solvent.

[0049] The component (A) may be used alone or in combination of two or more. It is particularly preferred to use a combination of an organopolysiloxane represented by formula (A-1) and an organopolysiloxane represented by formula (A-3). In this case, the amount of the organopolysiloxane represented by formula (A-3) used is preferably 1 to 1,000 parts by mass, more preferably 10 to 500 parts by mass, per 100 parts by mass of the organopolysiloxane represented by formula (A-1).

[0050] [(B) Component] Component (B) is an organopolysiloxane in which, per molecule, there is only one alkenyl group or one silicon-bonded hydrogen atom (SiH group) located either on a side chain or at the end.

[0051] Such organopolysiloxanes include those represented by the following formula (B-1) or (B-2): These may be used alone or in combination of two or more. [ka]

[0052] In formula (B-1) or (B-2), R 17 ~R 25 are each independently a monovalent hydrocarbon group other than an aliphatic unsaturated hydrocarbon group. 1 ~Y 3 are each independently either an alkenyl-group-containing monovalent organic group, a hydrogen atom, or an organohydrogenpolysiloxane containing one hydrogen atom bonded to a silicon atom (SiH group).

[0053] In formula (B-1), g+h=1 is satisfied, and i is an integer that satisfies 0≦i≦10,000. g, h, and i preferably result in an alkenyl group or SiH group content of 0.0001 to 0.7 mol / 100 g.

[0054] In formula (B-2), j 1 and j 2 is (j 2 +1) / j 1 is 0.3 to 4.0, and the alkenyl group or SiH group content is 0.0001 to 0.3 mol / 100 g.

[0055] The monovalent hydrocarbon group other than the aliphatic unsaturated hydrocarbon group is preferably one having 1 to 10 carbon atoms, 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. Of these, alkyl groups such as methyl or phenyl are preferred.

[0056] The alkenyl-containing monovalent organic group preferably has 2 to 10 carbon atoms, and examples thereof include alkenyl groups such as vinyl, allyl, hexenyl, and octenyl; (meth)acryloylalkyl groups such as acryloylpropyl, acryloylmethyl, and methacryloylpropyl; (meth)acryloxyalkyl groups such as acryloxypropyl, acryloxymethyl, methacryloxypropyl, and methacryloxymethyl; and alkenyl-containing monovalent hydrocarbon groups such as cyclohexenylethyl and vinyloxypropyl. Of these, vinyl is preferred from an industrial viewpoint.

[0057] As the organopolysiloxane in which the hydrogen atom bonded to the silicon atom (SiH group) is located either on a side chain or at a terminal, Y 1 ~Y 3 is an organohydrogenpolysiloxane containing a hydrogen atom or one hydrogen atom bonded to a silicon atom, but from an industrial viewpoint, a hydrogen atom is preferred.

[0058] The organopolysiloxane represented by formula (B-1), in which only one alkenyl group or silicon-bonded hydrogen atom (SiH group) is located in a side chain or at an end per molecule, is preferably in the form of an oil or a crude rubber.

[0059] The viscosity at 25°C of organopolysiloxanes containing only one alkenyl group or one silicon-bonded hydrogen atom (SiH group) per molecule, either in a side chain or at a terminal, of component (B) is preferably 1 to 5,000 mPa·s, more preferably 5 to 500 mPa·s. The viscosity here was measured at 25°C in accordance with JIS Z 8803. The viscometer used may be selected appropriately depending on the viscosity; for example, an E-type viscometer (RE-85R manufactured by Toki Sangyo Co., Ltd.) is preferably used.

[0060] The number average molecular weight (Mn) of the organopolysiloxane of component (B) is preferably 2 to 10,000, and more preferably 2 to 1,000. Mn within this range is preferable in terms of workability associated with the viscosity of the composition and processability associated with the storage modulus after curing.

[0061] Although two or more types of component (B) may be used in combination, it is preferable to use one type alone. In this case, the amount of component (B) used is preferably 0.1 to 1,000 parts by mass, and more preferably 0.1 to 100 parts by mass, per 100 parts by mass of the organopolysiloxane represented by formula (A-1).

[0062] [(C) component] Component (C) is a crosslinking agent, and is an organohydrogenpolysiloxane having at least two, preferably three or more, silicon-bonded hydrogen atoms (SiH groups) per molecule. The organohydrogenpolysiloxane may be linear, branched, or cyclic. The organohydrogenpolysiloxane may be used alone or in combination of two or more.

[0063] The viscosity of the organohydrogenpolysiloxane of component (C) at 25°C is preferably 1 to 5,000 mPa·s, and more preferably 5 to 500 mPa·s. The viscosity here was measured at 25°C in accordance with JIS Z 8803. The viscometer used can be selected appropriately depending on the viscosity, but an E-type viscometer (RE-85R manufactured by Toki Sangyo Co., Ltd.) is suitable, for example.

[0064] The Mn of the organohydrogenpolysiloxane of component (C) is preferably 100 to 100,000, and more preferably 500 to 10,000. Mn within this range is preferable in terms of workability associated with the viscosity of the composition and processability associated with the storage modulus after curing.

[0065] Component (C) is preferably blended so that the molar ratio (SiH groups / alkenyl groups) of the total SiH groups in components (B) and (C) to the total alkenyl groups in components (A) and (B) is 0.3 to 10, more preferably 0.5 to 5.0. A molar ratio of 0.3 or higher prevents low crosslink density and problems such as non-curing of the temporary adhesive layer. Furthermore, a molar ratio of 5 or lower prevents excessively high crosslink density, providing sufficient adhesive strength and tack, thereby extending the usable life of the treatment solution. The molar ratio (SiH groups / alkenyl groups) was calculated from the measured values ​​of SiH per 100 g (mol / 100 g) and alkenyl groups per 100 g (mol / 100 g). The molar ratio (SiH groups / alkenyl groups) in the Preparation Examples was calculated using the following formula: [(SiH group content of POHS / 100) x amount of POHS added] / {[(Alkenyl group content of PDMS / 100) × Amount of PDMS added] + [(Alkenyl group content of PVMS / 100) × Amount of PVMS added]} (In the above formula, POHS: organohydrogenpolysiloxane, PDMS: dimethylpolysiloxane, PVMS: vinylmethylpolysiloxane with a resin structure)

[0066] [(D) component] Component (D) is a non-functional organopolysiloxane. Here, "non-functional" means that the molecule does not contain any reactive groups such as alkenyl groups, hydroxy groups, alkoxy groups, or epoxy groups bonded directly to silicon atoms or via any other group, nor does the molecule contain any hydrogen or halogen atoms bonded directly to silicon atoms.

[0067] Examples of such non-functional organopolysiloxanes include organopolysiloxanes having unsubstituted or substituted monovalent hydrocarbon groups other than aliphatic unsaturated hydrocarbon groups, having 1 to 12 carbon atoms, preferably 1 to 10 carbon atoms. 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. Some or all of the hydrogen atoms in these groups may be substituted with halogen atoms such as chlorine, fluorine, and bromine. Examples of such groups include halogenated alkyl groups such as chloromethyl, 3-chloropropyl, and 3,3,3-trifluoropropyl. The monovalent hydrocarbon group is preferably an alkyl group or an aryl group, more preferably a methyl group or a phenyl group.

[0068] The molecular structure of the non-functional organopolysiloxane of component (D) is not particularly limited and may be linear, branched, cyclic, or any other structure. However, linear or branched organopolysiloxanes are preferred, and linear diorganopolysiloxanes in which the main chain is essentially composed of repeating diorganosiloxane units and both molecular chain terminals are blocked with triorganosiloxy groups are preferred.

[0069] The viscosity (25°C) of the non-functional organopolysiloxane, a 30% by weight solution in toluene, is preferably 100 to 500,000 mPa·s, more preferably 200 to 100,000 mPa·s, from the viewpoints of workability of the composition, coatability to substrates, mechanical properties of the cured product, and support peelability. A viscosity within this range is preferred because it has an appropriate molecular weight, prevents volatilization during heat curing of the silicone resin composition, provides sufficient effectiveness, does not cause wafer cracking during wafer thermal processes such as CVD, and provides good workability and coatability. The viscosity here was measured at 25°C in accordance with JIS Z 8803. The viscometer used can be selected appropriately depending on the viscosity; for example, an E-type viscometer (RE-85R manufactured by Toki Sangyo Co., Ltd.) is suitable.

[0070] Examples of the non-functional organopolysiloxane include dimethylsiloxane polymers capped at both molecular chain terminals with trimethylsiloxy groups, phenylmethylpolysiloxanes capped at both molecular chain terminals with trimethylsiloxy groups, 3,3,3-trifluoropropylmethylsiloxane polymers capped at both molecular chain terminals with trimethylsiloxy groups, dimethylsiloxane-methylphenylsiloxane copolymers capped at both molecular chain terminals with trimethylsiloxy groups, dimethylsiloxane-3,3,3-trifluoropropylmethyl copolymers capped at both molecular chain terminals with trimethylsiloxy groups, and dimethylsiloxane-3,3,3-trifluoropropylmethyl copolymers capped at both molecular chain terminals with trimethylsiloxy groups. Examples of suitable siloxanes include methylphenylsiloxane-3,3,3-trifluoropropylmethyl copolymers, dimethylsiloxane-3,3,3-trifluoropropylmethylsiloxane-methylphenylsiloxane copolymers terminated at both molecular chain ends with trimethylsiloxy groups, dimethylpolysiloxanes terminated at both molecular chain ends with dimethylphenylsiloxy groups, methylphenylpolysiloxanes terminated at both molecular chain ends with dimethylphenylsiloxy groups, and dimethylsiloxane-methylphenylsiloxane copolymers terminated at both molecular chain ends with dimethylphenylsiloxy groups.

[0071] The non-functional organopolysiloxane of component (D) may be used alone or in combination of two or more. It is preferably in the form of an oil or a crude rubber. The amount of component (D) is 0.1 to 200 parts by mass per 100 parts by mass of component (A).

[0072] [(E) component] Component (E) is a hydrosilylation catalyst, preferably a platinum group metal-based hydrosilylation catalyst. Component (E) promotes the addition reaction between the alkenyl groups in components (A) and (B) and the hydrosilyl groups in components (B) and (C). It can be classified as a thermally activated hydrosilylation catalyst (E-1) that is activated by heat, or a photoactivated hydrosilylation catalyst (E-2) that is activated by light. These hydrosilylation catalysts are generally compounds of noble metals and are expensive, so platinum or platinum compounds, which are relatively readily available, are often used.

[0073] That is, the curable silicone resin composition is preferably one that can be cured by light and / or heat.

[0074] (E-1) Thermally activated hydrosilylation catalyst Examples of platinum compounds include chloroplatinic acid or complexes of chloroplatinic acid with olefins such as ethylene, complexes with alcohols or vinylsiloxanes, and metallic platinum supported on silica, alumina, carbon, etc. As platinum group metal catalysts other than platinum compounds, rhodium, ruthenium, iridium, and palladium compounds are also known, such as RhCl(PPh3)3, RhCl(CO)(PPh3)2, and Ru3(CO) 12 , IrCl(CO)(PPh3)2, Pd(PPh3)4, etc. In the above formula, Ph is a phenyl group.

[0075] (E-2) Photoactivatable hydrosilylation catalyst This photoactivated hydrosilylation catalyst is activated by irradiation with light, particularly ultraviolet light with a wavelength of 300 to 400 nm, and promotes the addition reaction between the alkenyl groups in components (A) and (B) and the hydrosilyl groups in components (B) and (C). This promotion effect is temperature-dependent, with higher promotion being achieved at higher temperatures. Therefore, after the preferred light irradiation, it is preferable to use the catalyst at an ambient temperature of 0 to 200°C, more preferably 10 to 100°C, in order to complete the reaction within an appropriate reaction time.

[0076] The ligand of this catalyst is preferably one that shows catalytic activity under UV light with medium to long wavelengths, from UV-B to UV-A, in order to prevent damage to the wafer. Examples of such ligands include cyclic diene ligands and β-diketonato ligands.

[0077] From the above, preferred examples of the photoactivatable hydrosilylation reaction catalyst include, for example, a cyclic diene ligand type, such as (η 5-cyclopentadienyl)tri(σ-alkyl)platinum(IV) complexes, particularly (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), and the like, and also β-diketonato ligand type Examples of the platinum complex include β-diketonatoplatinum(II) or platinum(IV), particularly specifically trimethyl(acetylacetonato)platinum(IV), trimethyl(3,5-heptanedionato)platinum(IV), trimethyl(methylacetoacetate)platinum(IV), bis(2,4-pentanedionato)platinum(II), bis(2,4-hexanedionato)platinum(II), bis(2,4-heptanedionato)platinum(II), bis(3,5-heptanedionato)platinum(II), bis(1-phenyl-1,3-butanedionato)platinum(II), bis(1,3-diphenyl-1,3-propanedionato)platinum(II), and bis(hexafluoroacetylacetonato)platinum(II).

[0078] When using these catalysts, if they are solid catalysts, they can be used in solid form, but to obtain a more uniform cured product, it is preferable to use them dissolved in an appropriate solvent. In this case, appropriate solvent means a solvent that is soluble in any or all of components (A), (B), and (C) and is suitable for the working environment and process.

[0079] The amount of component (E) added is an effective amount, typically 0.1 to 5,000 ppm, preferably 1 to 1,000 ppm, calculated as the metal atom weight relative to the total mass of components (A), (B), (C), and (D). A content of 0.1 ppm or more does not impair the curability of the composition, nor does it reduce the crosslink density or holding power. A content of 5,000 ppm or less can suppress side reactions such as dehydrogenation during curing and extend the usable life of the treatment solution. The compounding ratio of components (E-1) to (E-2) is (E-1):(E-2) = 80:20 or 20:80, preferably 100:0 or 0:100. Component (E-1) alone can be heat-cured without the need for UV irradiation, while component (E-2) alone can be cured in a short time.

[0080] [Component (F)] The curable silicone resin composition may further contain a reaction inhibitor as component (F), which is optionally added as needed to prevent thickening or gelation of the composition when preparing the composition or applying it to a substrate.

[0081] Examples of the reaction inhibitor 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-butyne, 3-methyl-3-trimethylsiloxy-1-pentyne, 3,5-dimethyl-3-trimethylsiloxy-1-hexyne, 1-ethynyl-1-trimethylsiloxycyclohexane, bis(2,2-dimethyl-3-butynyloxy)dimethylsilane, 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane, 1,1,3,3-tetramethyl-1,3-divinyldisiloxane, etc. Among these, 1-ethynylcyclohexanol and 3-methyl-1-butyn-3-ol are preferred.

[0082] When the curable silicone resin composition containing the components (A) to (E) also contains component (F), its controllability differs depending on the chemical structure, so its content should be adjusted to an optimal amount for each component, but considering its effects on curability, storage stability, and post-curing physical properties, it is preferably 0.001 to 10 parts by mass, and more preferably 0.01 to 10 parts by mass, relative to the total mass of the components (A), (B), and (C). If the content of component (F) is within this range, the composition will have a long usable life, long-term storage stability, and good curability and workability.

[0083] The curable silicone resin composition further contains R A 3SiO 0.5 Units (wherein R A are each independently an unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms.) and an SiO2 unit, and R relative to the SiO2 unit A 3SiO 0.5 The unit of mole ratio (R A 3SiO 0.5 An organopolysiloxane having a SiO2 ratio (SiO2 / SiO2) of 0.3 to 1.8 may also be added, preferably in an amount of 0 to 500 parts by mass per 100 parts by mass of component (A).

[0084] To the curable silicone resin composition, known antioxidants such as phenol-based, quinone-based, and amine-based antioxidants can be added to improve heat resistance.

[0085] A filler such as silica may be added to the curable silicone resin composition in order to further increase the physical strength of the temporary adhesive layer obtained from the composition.

[0086] The curable silicone resin composition may be used in the form of a solution by adding a solvent for reasons such as improving workability and mixability by lowering the viscosity of the composition, adjusting the film thickness of the temporary adhesive layer, etc. The solvent used is not particularly limited as long as it can dissolve the components described above, but hydrocarbon solvents such as pentane, hexane, cyclohexane, isooctane, nonane, decane, p-menthane, pinene, isododecane, and limonene are preferred.

[0087] Examples of the solution-forming method include a method in which the curable silicone resin composition is prepared and then a solvent is added at the end to adjust the viscosity to the desired level, or a method in which the highly viscous components (A), (B) and / or (C) are pre-diluted with a solvent to improve workability and mixability, and then the remaining components are mixed in. Furthermore, the mixing method used to form the solution may be selected appropriately based on the viscosity of the composition and workability, such as a shaking mixer, a magnetic stirrer, or various mixers.

[0088] The amount of solvent to be added may be set as appropriate from the viewpoints of adjusting the viscosity and workability of the composition, and the film thickness of the temporary adhesive layer, but is preferably 5 to 900 parts by mass, and more preferably 10 to 400 parts by mass, per 100 parts by mass of the curable silicone resin composition.

[0089] The temporary adhesive layer can be formed by applying the curable silicone resin composition onto a substrate by a method such as spin coating, roll coating, etc. Among these, when the temporary adhesive layer is formed on a substrate by a method such as spin coating, it is preferable to coat the curable silicone resin composition in the form of a solution.

[0090] From the viewpoint of coatability, the viscosity of the curable silicone resin composition in solution at 25°C is preferably 1 to 100,000 mPa·s, and more preferably 10 to 10,000 mPa·s. The viscosity here was measured at 25°C in accordance with JIS Z 8803. The viscometer used may be selected appropriately depending on the viscosity, but an E-type viscometer (RE-85R manufactured by Toki Sangyo Co., Ltd.) is preferably used, for example.

[0091] The curable silicone resin composition has a 180° peel strength of typically 2 gf to 100 gf, preferably 3 gf to 50 gf, and more preferably 5 gf to 30 gf, at 25° C. after curing, on a 25 mm wide test piece (e.g., a glass test piece). If the strength is 2 gf or more, there is no risk of wafer misalignment during wafer grinding, and if the strength is 100 gf or less, the wafer can be easily peeled off.

[0092] The curable silicone resin composition has a storage modulus at 25° C. after curing of 1,000 Pa or more and 1,000 MPa or less, and preferably 10,000 Pa or more and 100 MPa or less. If the storage modulus is 1,000 Pa or more, the film formed is strong and there is no risk of wafer misalignment or associated wafer cracking during wafer grinding. If the storage modulus is 1,000 MPa or less, deformation stress during wafer thermal processes such as CVD can be alleviated, and the film is stable during wafer thermal processes.

[0093] When forming a laminate of substrate / temporary adhesive layer / support, the curable silicone resin composition can selectively control the interface at which the laminate is peeled off after formation by applying the curable silicone resin composition to the substrate side or the support side. That is, when the composition is applied to the substrate and a bonded structure is formed with the support and then peeled off, selective peeling is possible between the substrate and the temporary adhesive layer. In this case, the temporary adhesive layer remains as a residue on the support, which simplifies the subsequent substrate cleaning process and is preferable in terms of improved workability. On the other hand, when the target to which the curable silicone resin composition is applied is changed to the support and the bonded structure with the substrate is peeled off, selective peeling is possible at the temporary adhesive layer / support interface. In this case, the residue of the temporary adhesive layer remains on the substrate side, which may lead to reduced workability in the subsequent substrate cleaning process. However, when the composition is applied to the support side, it is less susceptible to influences that may be caused by the substrate used, such as curing inhibition in the hydrosilylation reaction, and is therefore more likely to function as a stable temporary adhesive.

[0094] [Method of manufacturing thin wafers] The method for producing a thin wafer of the present invention is characterized in that the temporary adhesive for wafer processing is used to temporarily bond a wafer having semiconductor circuits or the like to a support.

[0095] The method for producing a thin wafer of the present invention includes the following steps (a) to (e). (a) forming a wafer laminate by releasably adhering 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; (b) curing the temporary adhesive; (c) grinding or polishing the non-circuit-forming surfaces of the wafers in the wafer stack; (d) processing the non-circuit-forming surface of the wafer; (e) peeling the processed wafer from the support; A method for manufacturing a thin wafer, comprising:

[0096] [Process (a)] Step (a) is a temporary bonding step in which 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 is releasably bonded to a support using the temporary adhesive for wafer processing to form a wafer laminate.

[0097] Specifically, any one of the following methods is applied: a method of forming a temporary adhesive layer on the surface of the wafer using the temporary adhesive for wafer processing, and bonding the support and the surface of the wafer via the temporary adhesive layer; a method of forming a temporary adhesive layer on the surface of a support using the temporary adhesive for wafer processing, and bonding the support and the surface of the wafer via the temporary adhesive layer; or a method of forming temporary adhesive layers on both the surface of the wafer and the surface of the support using the temporary adhesive for wafer processing, and bonding the support and the surface of the wafer via the temporary adhesive layer.

[0098] The wafers applicable to the present invention are typically semiconductor wafers. Examples of the semiconductor wafers include not only silicon wafers but also germanium wafers, gallium-arsenide wafers, gallium-phosphorus wafers, and gallium-arsenide-aluminum wafers. The thickness of the wafer is not particularly limited, but is typically 600 to 800 μm, more typically 625 to 775 μm.

[0099] The support may be a substrate such as a silicon wafer, a glass plate, or a quartz wafer, but is not limited to these. In the present invention, when the curable silicone resin composition is cured without being irradiated with light through the support, the support may not be light-transmitting. On the other hand, when the curable silicone resin composition is cured by being irradiated with light through the support, it is preferable to use a support that is light-transmitting.

[0100] The temporary adhesive layer may be formed by laminating a film formed from the curable silicone resin composition on a wafer or a support, or by applying the curable silicone resin composition by a method such as spin coating or roll coating. When the curable silicone resin composition is a solution containing a solvent, after application, the composition is prebaked in advance at a temperature of preferably 40 to 200°C, more preferably 50 to 150°C, depending on the evaporation conditions of the solvent, before use.

[0101] The temporary adhesive layer is preferably formed and used with 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, when the temporary adhesive layer is applied to a substrate, the temporary adhesive layer can be applied to the entire substrate without leaving any uncoated areas. On the other hand, if the film thickness is 500 μm or less, the temporary adhesive layer can withstand the grinding process when forming a thin wafer.

[0102] The method for bonding the support and the wafer surface via the temporary adhesive layer includes a method of uniformly pressing them together under reduced pressure, preferably in a temperature range of 10 to 200°C, more preferably 20 to 150°C.

[0103] The pressure when pressing the wafer on which the temporary adhesive layer has been formed and the support body together is preferably 0.01 to 10 MPa, more preferably 0.1 to 1.0 MPa, depending on the viscosity of the temporary adhesive layer. If the pressure is 0.01 MPa or more, the circuit formation surface and the space between the wafer and the support body can be filled with the temporary adhesive layer, and if the pressure is 10 MPa or less, there is no risk of the wafer cracking or deterioration of the flatness of the wafer and the temporary adhesive layer, and subsequent wafer processing is favorable.

[0104] Wafer bonding can be performed using a commercially available wafer bonder, such as EVG520IS or 850TB manufactured by EVG, or XBS300 manufactured by SUSS MicroTec.

[0105] [Step (b)] Step (b) is a step of curing the temporary adhesive layer. In the case of a thermosetting silicone resin composition, after forming the wafer laminate, the temporary adhesive layer is cured by heating preferably at 50 to 300°C, more preferably at 100 to 200°C, for preferably 1 minute to 4 hours, more preferably 5 minutes to 2 hours. In the case of a photocurable resin composition, after the wafer processed body (laminate substrate) is formed, light may be irradiated from the light-transmitting support side to photocure the temporary adhesive layer, or the wafer processed body (laminate substrate) may be formed using a photocurable silicone resin composition that has been irradiated with light in advance, and then cured. The type of actinic ray used in this case is not particularly limited, but ultraviolet light is preferred, and ultraviolet light with a wavelength of 300-400 nm is more preferred. The ultraviolet irradiation dose (illuminance) is 100 mJ / cm as an integrated light amount. 2 ~100,000mJ / cm 2 , preferably 500 mJ / cm 2 ~10,000mJ / cm 2 , more preferably 1,000 to 5,000 mJ / cm 2 In order to obtain good curability, it is desirable that the UV irradiation amount (illuminance) is equal to or greater than the lower limit of the above range, sufficient energy is obtained to activate the photoactivated hydrosilylation reaction catalyst in the temporary adhesive layer, and a sufficient cured product can be obtained. On the other hand, if the UV irradiation amount (illuminance) is equal to or less than the upper limit of the above range, sufficient energy is irradiated onto the composition, and a sufficient cured product can be obtained without decomposition of the components in the polymer layer or partial deactivation of the catalyst.

[0106] The ultraviolet light may be light having multiple emission spectra or light having a single emission spectrum. The single emission spectrum may be a broad spectrum in the range of 300 nm to 400 nm. Light having a single emission spectrum is light having a peak (i.e., maximum peak wavelength) in the range of 300 nm to 400 nm, preferably 350 nm to 380 nm. Examples of light sources for irradiating such light include ultraviolet light-emitting diodes (ultraviolet LEDs) and ultraviolet light-emitting semiconductor element light sources such as ultraviolet light-emitting semiconductor lasers.

[0107] Examples of light sources that irradiate light having multiple emission spectra include lamps such as metal halide lamps, xenon lamps, carbon arc lamps, chemical lamps, sodium lamps, low-pressure mercury lamps, high-pressure mercury lamps, and ultra-high-pressure mercury lamps; gas lasers such as nitrogen; liquid lasers using organic dye solutions; and solid-state lasers in which rare earth ions are incorporated into inorganic single crystals.

[0108] When the light has a peak in the wavelength range shorter than 300 nm in its emission spectrum, or when there are wavelengths in the wavelength range shorter than 300 nm that have an irradiance greater than 5% of the irradiance of the maximum peak wavelength in the emission spectrum (e.g., when the emission spectrum is broad across a wide wavelength range), and when a substrate that is optically transparent to wavelengths shorter than 300 nm, such as a quartz wafer, is used as the support, it is preferable to remove light with wavelengths shorter than 300 nm using an optical filter to obtain a satisfactory cured product. This reduces the irradiance of each wavelength shorter than 300 nm to 5% or less, preferably 1% or less, more preferably 0.1% or less, and even more preferably 0% of the irradiance of the maximum peak wavelength. When the emission spectrum has multiple peaks in the wavelength range from 300 nm to 400 nm, the peak wavelength showing the greatest absorbance among them is taken as the maximum peak wavelength. There are no particular limitations on the optical filter, as long as it cuts wavelengths shorter than 300 nm. Any known optical filter can be used. For example, a 365 nm bandpass filter can be used. The illuminance and spectral distribution of ultraviolet light can be measured using a spectroradiometer, for example, USR-45D (Ushio Inc.).

[0109] The light irradiation device is not particularly limited, but for example, a spot type irradiation device, a surface type irradiation device, a line type irradiation device, a conveyor type irradiation device, or the like can be used.

[0110] When curing a photocurable silicone resin composition, the light irradiation time cannot be generally specified because it depends on the illuminance. However, by adjusting the illuminance to, for example, 1 to 300 seconds, preferably 10 to 200 seconds, and more preferably 30 to 150 seconds, the irradiation time is appropriately short and does not cause any particular problems in the work process. Furthermore, the photocurable silicone resin composition that has been irradiated with light gels after 1 to 120 minutes, particularly 5 to 60 minutes, of irradiation. In this invention, gelation refers to a state in which the curing reaction of the photocurable silicone resin composition has partially progressed and the composition has lost its fluidity.

[0111] Furthermore, since the curing rate of the photocurable silicone resin composition after irradiation with light depends on the ambient temperature, it is preferable to leave the wafer processed body (laminate substrate) at a temperature of preferably 20 to 150°C, more preferably 30 to 100°C, from the viewpoint of improving workability.

[0112] [Process (c)] Step (c) is a step of grinding or polishing the non-circuit surface of the wafer temporarily bonded to the support, i.e., a step of grinding the backside of the wafer of the wafer laminate obtained in the previous step to reduce the thickness of the wafer. There are no particular limitations on the method of grinding the backside of the wafer, and any known grinding method can be used. Grinding is preferably performed while cooling the wafer and grinding stone (diamond, etc.) by spraying water on them. An example of an apparatus for grinding the backside of the wafer is the DAG-810 (trade name) manufactured by Disco Corporation. Alternatively, the backside of the wafer may be subjected to chemical mechanical polishing (CMP).

[0113] [Step (d)] Step (d) is a process for processing the non-circuit surface of the wafer laminate whose non-circuit surface has been ground in step (c). That is, this process processes the non-circuit surface of the wafer of the wafer laminate thinned by backside grinding. This process includes various processes used at the wafer level. Examples include electrode formation, metal wiring formation, and protective film formation. More specifically, this process includes conventionally known processes such as metal sputtering for forming electrodes, wet etching of the metal sputtered layer, pattern formation by applying, exposing, and developing a resist to serve as a mask for metal wiring formation, resist stripping, dry etching, metal plating, silicon etching for TSV formation, and oxide film formation on the silicon surface.

[0114] [Step (e)] Step (e) is a step of peeling the wafer processed in step (d) from the support, i.e., a step of peeling the wafer from the support after various processing has been performed on the thinned wafer and before dicing. This peeling step is generally performed under relatively mild conditions, such as room temperature to about 60°C. Examples of peeling methods include fixing one of the wafers or the support of the wafer stack horizontally and lifting the other at a certain angle from the horizontal, or attaching a protective film to the ground surface of the ground wafer and peeling the wafer and protective film from the wafer stack using a peel method. When using these peeling methods, the peeling step is usually performed at room temperature.

[0115] Also, step (e) is (e1) a step of attaching a dicing tape to the wafer surface of the processed wafer; (e2) vacuum-adsorbing the dicing tape surface onto the adsorption surface; and (e3) A step of peeling off the support from the processed wafer while keeping the temperature of the adsorption surface in the range of 10 to 100°C. In this way, the support can be easily peeled off from the processed wafer, and the subsequent dicing step can be easily carried out.

[0116] Also, after step (e), (f) A step of removing the temporary adhesive layer remaining on the circuit-formed surface of the peeled wafer. A portion of the temporary adhesive layer may remain on the circuit-forming surface of the wafer peeled off from the support in step (e), and the temporary adhesive layer can be removed by, for example, washing the wafer.

[0117] In this step (f), any cleaning liquid can be used as long as it dissolves the silicone resin of the temporary adhesive layer, and specific examples include pentane, hexane, cyclohexane, decane, isononane, p-menthane, pinene, isododecane, limonene, etc. These solvents may be used alone or in combination of two or more.

[0118] Furthermore, if the temporary adhesive layer is difficult to remove, a base or an acid may be added to the cleaning solution. Examples of the base include amines such as ethanolamine, diethanolamine, triethanolamine, triethylamine, and ammonia; and ammonium salts such as tetramethylammonium hydroxide. Examples of the acid include organic acids such as acetic acid, oxalic acid, benzenesulfonic acid, and dodecylbenzenesulfonic acid. The amount of the base or acid added is such that the concentration in the cleaning solution is preferably 0.01 to 10% by mass, more preferably 0.1 to 5% by mass. To improve the removability of residues, a conventional surfactant may be added. The SPIS-TA-CLEANER series (manufactured by Shin-Etsu Chemical Co., Ltd.), which is available as a wafer cleaner, can also be suitably used.

[0119] The wafer can be washed using the cleaning solution with a paddle, spraying, or immersing in a cleaning solution tank. The temperature during washing is preferably 10 to 80° C., more preferably 15 to 65° C. If necessary, the temporary adhesive layer may be dissolved in the cleaning solution, and then the wafer may be finally rinsed with water or alcohol and dried.

[0120] The thickness of the thin wafer obtained by the production method of the present invention is typically 5 to 300 μm, and more typically 10 to 100 μm.

[0121] [Wafer stack] The present invention provides a wafer laminate comprising a support, a temporary adhesive layer obtained from the above-described temporary adhesive for wafer processing laminated thereon, and a wafer having a circuit-forming surface on its front side and a non-circuit-forming surface on its back side, wherein the temporary adhesive layer is releasably adhered to the front side of the wafer. [Example]

[0122] The present invention will be explained in more detail below with reference to Preparation Examples, Comparative Preparation Examples, Examples, and Comparative Examples, but the present invention is not limited to these Examples. The viscosity here was measured at 25°C in accordance with JIS Z 8803. The viscometer to be used may be selected appropriately depending on the viscosity, and for example, an E-type viscometer (RE-85R manufactured by Toki Sangyo Co., Ltd.) can be suitably used.

[0123] [1] Preparation of curable silicone resin solution [Preparation Example 1] A solution of 100 parts by mass of polydimethylsiloxane having an alkenyl content of 0.0336 mol / 100 g and a number average molecular weight (Mn) of 30,000 and 200 parts by mass of xylene was added with SiO 4 / 2 Units (Q units) 50 mol%, (CH3)3SiO 1 / 2 Units (M units) 48 mol% and (CH2=CH)(CH3)2SiO 1 / 2 Unit (M Vi Units) A solution consisting of 50 parts by mass of vinylmethylpolysiloxane (Component A) with an alkenyl content of 0.0282 mol / 100 g and an Mn of 7,000, consisting of 2 mol%, and 100 parts by mass of xylene, 5 parts by mass of vinyldimethylpolysiloxane (Component B) with an alkenyl content of 0.0125 mol / 100 g and an Mn of 8,000, and having one vinyl group at one end, (CH3)2SiO 2 / 2 Units (D units) 83.9 mol%, (CH3)HSiO 2 / 2 Unit (D H25 parts by mass of organohydrogenpolysiloxane (Component C) with a SiH group content of 0.222 mol / 100 g (expressed as 16.1 mol%) and Mn of 2,400, 50 parts by mass of dimethylpolysiloxane (Component D) capped at both ends with trimethylsiloxy groups and having a viscosity of 30,000 mPa·s in a 30% by mass toluene solution at 25°C, 120 parts by mass of xylene, and 0.6 parts by mass of 1-ethynylcyclohexanol were mixed together. Then, 0.4 parts by mass of hydrosilylation catalyst CAT-PL-5 (Component E) was added, and the mixture was filtered through a 0.2 μm membrane filter to prepare thermosetting silicone resin solution A1. The viscosity of resin solution A1 at 25°C was 2,400 mPa·s. The Si-H / Si-Vi (molar ratio) in this Preparation Example 1 was 1.2.

[0124] [Preparation Example 2] A solution of 100 parts by mass of polydimethylsiloxane having an alkenyl content of 0.0336 mol / 100 g and a number average molecular weight (Mn) of 30,000 and 200 parts by mass of xylene was added with SiO 4 / 2 Units (Q units) 50 mol%, (CH3)3SiO 1 / 2 Units (M units) 48 mol% and (CH2=CH)(CH3)2SiO 1 / 2 Unit (M Vi Units: A solution consisting of 50 parts by mass of vinylmethylpolysiloxane (Component A) with an alkenyl content of 2 mol% and an Mn of 7,000 (0.0282 mol / 100 g) and 100 parts by mass of xylene, 5 parts by mass of organohydrogenpolydimethylsiloxane (Component B) with one SiH group at one end and an SiH group content of 0.0100 mol / 100 g and an Mn of 10,000, (CH3)2SiO 2 / 2 Units (D units) 83.9 mol%, (CH3)HSiO 2 / 2 Unit (D H35 parts by mass of organohydrogenpolysiloxane (Component C) with a SiH group content of 0.222 mol / 100 g (expressed as 16.1 mol%) and Mn of 2,400, 50 parts by mass of dimethylpolysiloxane (Component D) capped at both ends with trimethylsiloxy groups and having a viscosity of 1,000 mPa·s in a 30% by mass toluene solution at 25°C, 120 parts by mass of xylene, and 0.6 parts by mass of 1-ethynylcyclohexanol were mixed together. Then, 0.4 parts by mass of hydrosilylation catalyst CAT-PL-5 (Component E) was added and the mixture was filtered through a 0.2 μm membrane filter to prepare thermosetting silicone resin solution A2. The viscosity of resin solution A2 at 25°C was 1,200 mPa·s. The Si-H / Si-Vi (molar ratio) in this Preparation Example 2 was 1.6.

[0125] [Preparation Example 3] A solution of 100 parts by mass of polydimethylsiloxane with a phenyl group content of 0.127 mol / 100 g, an alkenyl group content of 0.0248 mol / 100 g, an Mn of 30,000, and 200 parts by mass of xylene was added to the solution. 4 / 2 Units (Q units) 50 mol%, (CH3)3SiO 1 / 2 Units (M units) 48 mol% and (CH2=CH)(CH3)2SiO 1 / 2 Unit (M Vi Units) A solution consisting of 50 parts by mass of vinylmethylpolysiloxane (Component A) with a resin structure consisting of 2 mol% alkenyl group content of 0.0282 mol / 100 g and Mn of 7,000, and 100 parts by mass of xylene, 5 parts by mass of vinyldimethylpolysiloxane (Component B) with an alkenyl group content of 0.0125 mol / 100 g and Mn of 8,000, and one vinyl group at one end, (CH3)2SiO 2 / 2 Units (D units) 83.9 mol%, (CH3)HSiO 2 / 2 Unit (D HA solution consisting of 10 parts by mass of organohydrogenpolysiloxane (Component C) with a SiH group content of 0.222 mol / 100 g (expressed as 16.1 mol%) and Mn of 2,400, 50 parts by mass of dimethylpolysiloxane (Component D) capped with trimethylsiloxy groups at both ends of the molecular chain (a 30% by mass toluene solution with a viscosity of 100,000 mPa·s at 25°C), 120 parts by mass of xylene, and 0.6 parts by mass of 1-ethynylcyclohexanol was added and mixed. Further, 0.4 parts by mass of hydrosilylation catalyst CAT-PL-5 (Shin-Etsu Chemical Co., Ltd., platinum concentration 1.0% by mass) (Component E) was added, and the mixture was filtered through a 0.2 μm membrane filter to prepare thermosetting silicone resin solution A3. The viscosity of resin solution A3 at 25°C was 3,300 mPa·s. In addition, the Si-H / Si-Vi (molar ratio) in Preparation Example 3 is 0.56.

[0126] [Preparation Example 4] A solution of 100 parts by mass of polydimethylsiloxane with a phenyl group content of 0.127 mol / 100 g, an alkenyl group content of 0.0248 mol / 100 g, an Mn of 30,000, and 200 parts by mass of xylene was added to the solution. 4 / 2 Units (Q units) 50 mol%, (CH3)3SiO 1 / 2 Units (M units) 48 mol% and (CH2=CH)(CH3)2SiO 1 / 2 Unit (M Vi Units: A solution consisting of 50 parts by mass of vinylmethylpolysiloxane (Component A) with a resin structure consisting of 2 mol% alkenyl group content of 0.0282 mol / 100 g and Mn of 7,000, and 100 parts by mass of xylene; 5 parts by mass of organohydrogenpolydimethylsiloxane (Component B) with one SiH group at one end and SiH group content of 0.0100 mol / 100 g and Mn of 10,000; (CH3)2SiO 2 / 2 Units (D units) 83.9 mol%, (CH3)HSiO 2 / 2 Unit (D HA solution consisting of 20 parts by mass of organohydrogenpolysiloxane (Component C) with a SiH group content of 0.222 mol / 100 g (expressed as 16.1 mol%) and Mn of 2,400, 50 parts by mass of dimethylpolysiloxane (Component D) capped with trimethylsiloxy groups at both ends of the molecular chain (a 30% by mass toluene solution with a viscosity of 30,000 mPa·s at 25°C), 120 parts by mass of xylene, and 0.6 parts by mass of 1-ethynylcyclohexanol was added and mixed. Further, 0.4 parts by mass of hydrosilylation catalyst CAT-PL-5 (Shin-Etsu Chemical Co., Ltd., platinum concentration 1.0% by mass) (Component E) was added, and the mixture was filtered through a 0.2 μm membrane filter to prepare thermosetting silicone resin solution A4. The viscosity of resin solution A4 at 25°C was 2,500 mPa·s. In addition, the Si-H / Si-Vi (molar ratio) in Preparation Example 4 is 1.2.

[0127] [Preparation Example 5] Thermosetting silicone resin solution A5 was prepared in the same manner as in Preparation Example 1 above, except that a vinyldimethylpolysiloxane (alkenyl group content: 0.0125 mol / 100 g, Mn: 8,000, 5 parts by mass) having one vinyl group on a side chain (component B) was added instead of the vinyldimethylpolysiloxane (alkenyl group content: 0.0125 mol / 100 g, Mn: 8,000, 5 parts by mass) having one vinyl group on one end. The viscosity of resin solution A5 at 25°C was 2,400 mPa·s. The Si-H / Si-Vi (molar ratio) in Preparation Example 5 was 1.2.

[0128] [Preparation Example 6] Thermosetting silicone resin solution A6 was prepared in the same manner as in Preparation Example 2 above, except that organohydrogenpolydimethylsiloxane having one SiH group on a side chain (SiH group content: 0.0100 mol / 100 g, Mn: 10,000, 5 parts by mass) (Component B) was added instead of organohydrogenpolydimethylsiloxane having one SiH group on one end (SiH group content: 0.0100 mol / 100 g, Mn: 10,000, 5 parts by mass). The viscosity of resin solution A6 at 25°C was 1,200 mPa·s. The Si-H / Si-Vi (molar ratio) in this Preparation Example 6 was 1.6.

[0129] [Preparation Example 7] Photocurable silicone resin solution A7 was prepared in the same manner as in Preparation Example 1 above, except that the hydrosilylation catalyst CAT-PL-5 (0.4 parts by mass) (Component E) was replaced with a photoactivated hydrosilylation catalyst: (methylcyclopentadienyl)trimethylplatinum(IV) toluene solution (platinum concentration 1.0% by mass) (Component E). The viscosity of resin solution A7 at 25°C was 2,400 mPa·s. The Si-H / Si-Vi (molar ratio) in this Preparation Example 7 was 1.2.

[0130] [Preparation Example 8] Photocurable silicone resin solution A8 was prepared in the same manner as in Preparation Example 2 above, except that the hydrosilylation catalyst CAT-PL-5 (0.4 parts by mass) (Component E) was replaced with a photoactivated hydrosilylation catalyst: (methylcyclopentadienyl)trimethylplatinum(IV) toluene solution (platinum concentration 1.0% by mass) (Component E) (0.4 parts by mass). The viscosity of resin solution A8 at 25°C was 1,200 mPa·s. The Si-H / Si-Vi (molar ratio) in this Preparation Example 8 was 1.6.

[0131] [Comparative Preparation Example 1] Thermosetting silicone resin solution CA1 was prepared in the same manner as in Preparation Example 1 above, except that 5 parts by mass of vinyldimethylpolysiloxane (Component B) with an Mn of 8,000 and an alkenyl group content of 0.0125 mol / 100 g containing one vinyl group at one end was omitted. The viscosity of resin solution CA1 at 25°C was 2,500 mPa·s. The Si-H / Si-Vi (molar ratio) in this Comparative Preparation Example 1 was 1.2.

[0132] [Comparative Preparation Example 2] Thermosetting silicone resin solution CA2 was prepared by replacing 5 parts by mass of vinyldimethylpolysiloxane (component B) having an alkenyl group content of 0.0125 mol / 100 g and an Mn of 8,000, which has one vinyl group at one end, with 5 parts by mass of vinyldimethylpolysiloxane having an alkenyl group content of 0.025 mol / 100 g and an Mn of 8,000, which has vinyl groups at both ends. The viscosity of resin solution CA2 at 25°C was 2,500 mPa·s. The Si-H / Si-Vi (molar ratio) in this Comparative Preparation Example 2 was 1.1.

[0133] [Comparative Preparation Example 3] Thermosetting silicone resin solution CA3 was prepared in the same manner as in Preparation Example 2 above, except that 5 parts by mass of organohydrogenpolydimethylsiloxane (Component B) with a SiH group content of 0.0100 mol / 100 g and a Mn of 10,000, containing one SiH group at each end, was not added. The viscosity of resin solution CA3 at 25°C was 1,300 mPa·s. The Si-H / Si-Vi (molar ratio) in this Comparative Preparation Example 3 was 1.6.

[0134] [Comparative Preparation Example 4] Thermosetting silicone resin solution CA4 was prepared by replacing 5 parts by mass of organohydrogenpolydimethylsiloxane (component B) having a SiH group content of 0.0200 mol / 100 g and a Mn of 10,000 with 5 parts by mass of organohydrogenpolydimethylsiloxane having SiH groups at both ends and a SiH group content of 0.0400 mol / 100 g with 10,000 SiH groups (component B) in the above Preparation Example 2. The viscosity of resin solution CA4 at 25°C was 1,300 mPa·s. The Si-H / Si-Vi (molar ratio) in this Comparative Preparation Example 4 was 1.6.

[0135] [Comparative Preparation Example 5] Photocurable silicone resin solution CA5 was prepared in the same manner as in Preparation Example 5 above, except that 5 parts by mass of vinyldimethylpolysiloxane (Component B) with an Mn of 8,000 and an alkenyl group content of 0.0125 mol / 100 g containing one vinyl group at one end was not added. The viscosity of resin solution CA5 at 25°C was 2,400 mPa·s. The Si-H / Si-Vi (molar ratio) in this Comparative Preparation Example 5 was 1.2.

[0136] [2] Fabrication and evaluation of wafer stacks [Examples 1 to 8 and Comparative Examples 1 to 5] Curable silicone resin solutions A1 to A8 and CA1 to CA5 were spin-coated onto a 200 mm diameter silicon wafer (thickness: 725 μm) with copper posts 10 μm high and 40 μm in diameter formed all over its surface, and heated in an oven at 100°C for 2 minutes to form a temporary adhesive layer on the wafer bump-forming surface with the film thickness shown in Table 1 below. Using a 200 mm diameter glass wafer (thickness: 500 μm) as a support, the silicon wafer and glass wafer with the temporary adhesive layer were each bonded to the glass wafer using an EVG520IS wafer bonding machine from EVG Corporation at 100°C for 2 minutes, 10 -3The wafers were bonded under vacuum at a pressure of 5 mbar or less and a load of 5 kN, followed by a curing process to produce a wafer laminate. The curing conditions were as follows: when a thermosetting silicone resin solution was used, the resin was heated in an oven at 180°C for 1 hour; when a photocurable silicone resin solution was used, the resin was cured using a surface-irradiation type UV-LED (wavelength 365 nm) irradiator at 23°C and 100 mW / cm. 2 The test was carried out by irradiating the sample with light for 120 seconds at an illuminance of 1.0.

[0137] The wafer laminate was then subjected to various tests using the following test methods, the results of which are shown in Table 1.

[0138] (1) Adhesion test In the wafer stack, the adhesion state of the wafer interface was visually confirmed from the glass support side, and if no abnormalities such as air bubbles were found at the interface, it was evaluated as good and indicated by "○", and if any abnormalities were found, it was evaluated as bad and indicated by "×".

[0139] (2) Back grinding resistance test Using the wafer stack, the backside of the silicon wafer was ground using a diamond grinding wheel in a grinder (DAG-810 manufactured by Disco Corporation). After grinding until the substrate thickness was 30 μm, the presence or absence of abnormalities such as cracks and peeling was examined using an optical microscope (100x magnification). If no abnormalities were found, the result was evaluated as good and indicated by "○", and if abnormalities were found, the result was evaluated as bad and indicated by "×".

[0140] (3) Heat resistance test (2) After the back grinding resistance test, the wafer stack was heated in an oven at 250°C for 1 hour, and then cooled to room temperature. The presence or absence of any abnormal appearance was visually inspected. If no abnormal appearance occurred, it was evaluated as good and indicated by "○", and if abnormal appearance such as voids, wafer swelling, or wafer breakage occurred, it was evaluated as bad and indicated by "×".

[0141] (4) Peelability test after heat resistance test To evaluate the substrate peelability, dicing tape (ELP UB-3083D, manufactured by Nitto Denko Corporation) was first attached to the wafer side of the wafer stack that had undergone the heat resistance test (3) using a dicing frame, and the dicing tape surface was then attached to an adsorption plate by vacuum suction. The glass wafer was then peeled off at room temperature by lifting a point on the glass with tweezers. A "good" indicates that the 30 μm-thick wafer could be peeled off without cracking, while an "x" indicates that cracking or other abnormalities occurred, resulting in a failure. It was also confirmed whether the temporary adhesive layer remained as residue on the substrate (silicon wafer) or the support (glass wafer).

[0142] (5) Washability test After the peelability test in (4), the 200 mm diameter wafer attached to the dicing frame via the dicing tape was placed on a spin coater with the peeled surface facing up. SPIS-TA-CLEANER 25 (Shin-Etsu Chemical Co., Ltd.) was sprayed onto the wafer as a cleaning solvent for 5 minutes, and then the wafer was rotated while being sprayed with isopropyl alcohol (IPA) to rinse. The appearance was then observed and visually checked for the presence or absence of residual adhesive. Those in which no residual resin was observed were evaluated as good and indicated by a circle, and those in which residual resin was observed were evaluated as poor and indicated by an x.

[0143] (6) Peel strength test Curable silicone resin solutions A1-A8 and CA1-CA5 were spin-coated onto a 200 mm diameter silicon wafer (725 μm thick) with 10 μm high, 40 μm diameter copper posts formed on its entire surface. The wafer was then heated on a hot plate at 100°C for 2 minutes to form a silicone resin layer with the thickness shown in Table 1 on the wafer bump surface. The silicone resin layer was then cured under the conditions shown in Table 1. After cooling to room temperature, five strips of 150 mm long x 25 mm wide polyimide tape were attached to the silicone resin layer on the wafer, and the temporary adhesive layer was removed from the tape-free areas. Using a Shimadzu Corporation AUTOGRAPH (AG-1) tool, the tape was peeled 120 mm from one edge at a 180° peel angle at 25°C and a speed of 300 mm / min. The average force applied (120 mm stroke x 5 times) was recorded as the initial peel strength of the silicone resin layer. In addition, a cured silicone resin layer was prepared on the surface of the wafer where the bumps were formed in the same manner as above, and the tape peel strength after heat treatment in an oven at 250°C in air for 1 hour was measured as the peel strength after heat resistance.

[0144] (7) Storage modulus measurement Curable silicone resin solutions A1 to A8 and CA1 to CA5 were each spin-coated onto a glass wafer and heated on a hot plate at 100°C for 2 minutes to form a silicone resin layer on the glass wafer with the film thickness shown in Table 1. The silicone resin layer was then cured under the conditions shown in Table 1 and cooled to room temperature. The glass wafer containing the resulting silicone resin layer was subjected to elastic modulus measurement at 25°C using a TA Instruments Ares G2 while sandwiched between 25 mmφ aluminum plates so that a load of 50 gf was applied to the silicone resin layer, and the obtained elastic modulus value was taken as the storage elastic modulus of the silicone resin layer.

[0145] (8) Thermogravimetry in air An appropriate amount of curable silicone resin solutions A1-A8 and CA1-CA5 was poured into a Teflon-coated mold measuring 100 mm H × 100 mm W × 1 mm D. After removing excess resin solution with a scraper, the mold was heated on a hot plate at 100°C for 2 minutes. The silicone resin layer was then cured under the conditions shown in Table 1 and cooled to room temperature to produce a cured silicone resin layer. Thermogravimetry was performed in air using 10 mg of the resulting cured product to determine the 1% weight loss temperature of the cured product. The apparatus used here was a Mettler-Toledo TGA2, and measurements were performed at 40-400°C (10°C / min).

[0146] [Table 1]

[0147] As shown in Table 1, it was confirmed that temporary adhesives made from curable silicone resin compositions containing organopolysiloxanes in which only one alkenyl group or only one silicon-bonded hydrogen atom (SiH group) is located in either a side chain or terminal position per molecule exhibit sufficient curability, and also have excellent wafer processing durability, peel stability after high-temperature and long-term heat treatment in air, and washability after peeling (Examples 1 to 8). On the other hand, in the comparative examples that did not contain organopolysiloxane in which only one alkenyl group or only one hydrogen atom bonded to a silicon atom (SiH group) per molecule was located either on a side chain or at an end, or in the comparative examples that had alkenyl groups or hydrogen atoms bonded to silicon atoms (SiH groups) at both ends, it was confirmed that high-temperature and long-term heat treatment had an adverse effect on the subsequent releasability (Comparative Examples 1 to 5).

[0148] The present specification includes the following aspects. [1] A temporary adhesive for wafer processing, for temporarily bonding a wafer to a support, the temporary adhesive for wafer processing being made of a curable silicone resin composition that can be cured by a hydrosilylation reaction, the curable silicone resin composition being characterized in that it contains an organopolysiloxane having only one alkenyl group or only one hydrogen atom bonded to a silicon atom (SiH group) per molecule. [2] The curable silicone resin composition is (A) organopolysiloxane having two or more alkenyl groups per molecule: 100 parts by mass, (B) an organopolysiloxane having only one alkenyl group or only one hydrogen atom bonded to a silicon atom (SiH group) per molecule: 0.1 to 100 parts by mass, (C) an organohydrogenpolysiloxane containing two or more silicon-bonded hydrogen atoms (SiH groups) per molecule: in an amount such that the total of the SiH groups in components (B) and (C) relative to the total of the alkenyl groups in components (A) and (B) is in a molar ratio of 0.3 to 5; (D) non-functional organopolysiloxane: 0.1 to 200 parts by mass, and (E) Hydrosilylation reaction catalyst: 0.1 to 5,000 ppm in terms of metal atomic weight based on the total mass of components (A), (B), (C), and (D). The temporary adhesive for wafer processing according to [1], characterized in that it contains [3] The temporary adhesive for wafer processing according to [2], characterized in that the organopolysiloxane having two or more alkenyl groups in one molecule of component (A) has at least one or more aryl groups. [4] The temporary adhesive for wafer processing according to [2] or [3], characterized in that it contains an organopolysiloxane in which only one alkenyl group or only one hydrogen atom bonded to a silicon atom (SiH group) is located in either a side chain or at the end per molecule. [5] The temporary adhesive for wafer processing according to any one of [2] to [4], wherein the curable silicone resin composition is curable by light and / or heat. [6] The temporary adhesive for wafer processing according to any one of [1] to [5], characterized in that the non-functional organopolysiloxane of component (D) is a dimethylpolysiloxane, the viscosity of which at 25°C is 100 to 500,000 mPa s in a 30% by mass toluene solution. [7] The temporary adhesive for wafer processing according to any one of [1] to [6], wherein the curable silicone resin composition containing the components (A) to (E) further contains a hydrosilylation reaction inhibitor as component (F) in an amount of 0.001 to 10 parts by mass, relative to the total mass of the components (A), (B), and (C). [8] The temporary adhesive for wafer processing according to any one of [1] to [7], characterized in that after the curable silicone resin composition has cured, the 180° peel strength of a 25 mm wide test piece against a silicon substrate at 25°C is 2 gf or more and 100 gf or less. [9] The temporary adhesive for wafer processing according to any one of [1] to [8], characterized in that after curing of the curable silicone resin composition, the storage modulus at 25°C is 1,000 Pa or more and 1,000 MPa or less.

[10] (a) a step of peelably adhering the circuit-forming surface of a wafer having a circuit-forming surface on its front side and a circuit-free surface on its back side to a support using the temporary adhesive for wafer processing according to any one of [1] to [9] to form a wafer laminate; (b) curing the temporary adhesive; (c) grinding or polishing the non-circuit-forming surfaces of the wafers in the wafer stack; (d) processing the non-circuit-forming surface of the wafer; (e) peeling the processed wafer from the support; A method for manufacturing a thin wafer, comprising:

[11] A wafer laminate comprising a support, a temporary adhesive layer obtained from the temporary adhesive for wafer processing according to any one of [1] to [9] laminated thereon, and a wafer having a circuit-forming surface on its front side and a circuit-free surface on its back side, wherein the temporary adhesive layer is releasably adhered to the front side of the wafer.

[0149] The present invention is not limited to the above-described embodiments. The above-described embodiments are merely examples, and anything that has substantially the same configuration as the technical idea described in the claims of the present invention and that exhibits similar effects is included within the technical scope of the present invention.

Claims

1. A temporary adhesive for wafer processing, for temporarily bonding a wafer to a support, the temporary adhesive for wafer processing being made of a curable silicone resin composition that can be cured by a hydrosilylation reaction, the curable silicone resin composition being characterized in that it contains an organopolysiloxane having only one alkenyl group or only one hydrogen atom bonded to a silicon atom (SiH group) per molecule.

2. The curable silicone resin composition comprises: (A) organopolysiloxane having two or more alkenyl groups per molecule: 100 parts by mass, (B) an organopolysiloxane having only one alkenyl group or only one hydrogen atom bonded to a silicon atom (SiH group) per molecule: 0.1 to 100 parts by mass; (C) an organohydrogenpolysiloxane containing two or more silicon-bonded hydrogen atoms (SiH groups) per molecule: in an amount such that the sum of the SiH groups in components (B) and (C) relative to the sum of the alkenyl groups in components (A) and (B) is a molar ratio of 0.3 to 5; (D) non-functional organopolysiloxane: 0.1 to 200 parts by mass, and (E) Hydrosilylation reaction catalyst: 0.1 to 5,000 ppm in terms of metal atom weight based on the total mass of components (A), (B), (C), and (D). The temporary adhesive for wafer processing according to claim 1, comprising:

3. 3. The temporary adhesive for wafer processing according to claim 2, wherein the organopolysiloxane having two or more alkenyl groups in one molecule of component (A) has at least one aryl group.

4. The temporary adhesive for wafer processing according to claim 2, characterized in that the non-functional organopolysiloxane of component (D) is a dimethylpolysiloxane having a viscosity of 100 to 500,000 mPa·s at 25°C in a 30% by mass toluene solution.

5. The temporary adhesive for wafer processing according to claim 2, wherein the curable silicone resin composition containing the components (A) to (E) further contains a hydrosilylation reaction inhibitor as a component (F) in an amount of 0.001 to 10 parts by mass, relative to the total mass of the components (A), (B), and (C).

6. 2. The temporary adhesive for wafer processing according to claim 1, characterized in that it contains an organopolysiloxane in which only one alkenyl group or only one hydrogen atom bonded to a silicon atom (SiH group) is located in either a side chain or at an end per molecule.

7. 2. The temporary adhesive for wafer processing according to claim 1, wherein the curable silicone resin composition is curable by light and / or heat.

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

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

10. (a) peelably adhering 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 according to any one of claims 1 to 9 to form a wafer laminate; (b) curing the temporary adhesive; (c) grinding or polishing the non-circuit-forming surfaces of the wafers in the wafer stack; (d) processing the non-circuit-forming surface of the wafer; (e) peeling the processed wafer from the support; A method for manufacturing a thin wafer, comprising:

11. A wafer laminate comprising a support, a temporary adhesive layer obtained from the temporary adhesive for wafer processing according to any one of claims 1 to 9 laminated thereon, and a wafer having a circuit-forming surface on its front surface and a circuit-free surface on its back surface, wherein the temporary adhesive layer is peelably adhered to the front surface of the wafer.

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