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

Abstract

Provided are: a wafer processing temporary adhesive that is for temporarily adhering a wafer to a support and that comprises a thermosetting silicone resin composition containing a non-functional organopolysiloxane; a wafer laminate; and a thin wafer manufacturing method.

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 Art

[0002] Three-dimensional semiconductor packaging has become essential for achieving further higher density and larger capacity. The three-dimensional packaging technology is a semiconductor manufacturing technology in which a single semiconductor chip is thinned and then stacked in multiple layers while being connected by through-silicon vias (TSVs). To achieve this, it is necessary to thin the substrate on which the semiconductor circuit is formed by grinding the non-circuit-forming surface (also referred to as the "back surface"), and further perform an electrode formation process including TSVs on the back surface. Conventionally, in the back grinding process of a silicon substrate, a back protection tape is attached to the opposite side of the grinding surface to prevent wafer breakage during grinding. However, this tape uses an organic resin film as a support substrate, and although it has flexibility, its strength and heat resistance are insufficient, and it is not suitable for performing the TSV formation process or the wiring layer formation process on the back surface.

[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, which can sufficiently withstand the processes of back grinding, TSV formation, and back electrode formation. At this time, the important part is the adhesive layer when bonding the substrate to the support. This requires that the substrate can be bonded to the support without gaps, has sufficient durability to withstand subsequent processes, and further that the thin wafer can be easily peeled off from the support at the end. Thus, since it is peeled off at the end, in this specification, this adhesive layer is also referred to as a temporary adhesive layer.

[0004] As known heretofore, as a temporary adhesive layer and its peeling method, there have been proposed a technique of irradiating an adhesive containing a light-absorbing substance with high-intensity light to decompose the adhesive layer and peeling the adhesive layer from the support (Patent Document 1), and a technique of using a heat-melting hydrocarbon-based compound as the adhesive and performing bonding and peeling in a heat-melted state (Patent Document 2). The former technique has problems such as the need for an expensive device such as a laser and a long processing time per substrate. Also, the latter technique is simple because it is controlled only by heating, but on the other hand, since the thermal stability at a high temperature exceeding 200°C is insufficient, the applicable range was narrow. Furthermore, these temporary adhesive layers were not suitable for forming a uniform film thickness on a high-step substrate and for complete adhesion to the support.

[0005] In addition, a technique of using a silicone adhesive for the temporary adhesive layer has been proposed. This is a method in which a substrate is adhered to a support using an addition-curing type silicone adhesive, and when peeling, the substrate is separated from the support by immersing it in a chemical agent that dissolves or decomposes the silicone resin (Patent Document 3). Therefore, it takes a very long time for peeling, and it is difficult to apply it to an actual manufacturing process. Also, it takes a long time to wash the silicone adhesive remaining as a residue on the substrate after peeling, and there are also problems in terms of washability.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0007] The present invention has been made in view of the above problems, and even when a high-step substrate is used, it has sufficient substrate holding property after bonding, high process compatibility with respect to the wafer back grinding process, TSV formation process, and wafer back wiring process, excellent wafer thermal process resistance, and on the other hand, is easy to peel in the peeling process, and has excellent residue cleaning property of the substrate after peeling, etc. 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 that lead to an improvement in the productivity of thin wafers.

Means for Solving the Problems

[0008] As a result of intensive studies to solve the above problems, the present inventors have found that the above problems can be solved by using a thermosetting silicone resin composition containing non-functional organopolysiloxane as a temporary adhesive, and have completed the present invention.

[0009] Therefore, the present invention provides the following temporary adhesive for wafer processing, wafer laminate, and method for manufacturing a thin wafer. 1. A temporary adhesive for wafer processing for temporarily bonding a wafer to a support, comprising a thermosetting silicone resin composition containing non-functional organopolysiloxane. 2. The thermosetting silicone resin composition containing the non-functional organopolysiloxane is (A) Organopolysiloxane having two or more alkenyl groups in one molecule: 100 parts by mass, (B) Organohydrogenpolysiloxane containing hydrogen atoms (SiH groups) bonded to two or more silicon atoms in one molecule: an amount such that the total of SiH groups in component (B) relative to the total of alkenyl groups in component (A) is 0.3 to 10 in molar ratio, (C) Non-functional organopolysiloxane: 0.1 to 200 parts by mass, and (D) Hydrosilylation reaction catalyst: 0.1 to 5,000 ppm in terms of metal atomic weight conversion with respect to the total mass of components (A), (B), and (C) The temporary adhesive for wafer processing of 1, which contains the above. 3. A temporary adhesive for wafer processing No. 2, wherein the viscosity at 25 °C of a 30% by mass toluene solution of a non-functional organopolysiloxane of component (C) is 100 to 500,000 mPa·s. 4. A temporary adhesive for wafer processing No. any one of 1 to 3, wherein the thermosetting silicone resin composition containing the non-functional organopolysiloxane further contains a hydrosilylation reaction control agent as component (E) in an amount of 0.001 to 10 parts by mass based on the total mass of components (A), (B) and (C). 5. A temporary adhesive for wafer processing No. any one of 1 to 4, wherein after curing of the thermosetting silicone resin composition containing the non-functional organopolysiloxane, the 180° peel adhesion force of a 25 mm wide test piece to a silicon substrate at 25 °C is 2 gf or more and 50 gf or less. 6. A temporary adhesive for wafer processing No. any one of 1 to 5, wherein after curing of the thermosetting silicone resin composition containing the non-functional organopolysiloxane, the storage elastic modulus at 25 °C is 1,000 Pa or more and 1,000 MPa or less. 7. (a) A step of releasably 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 a temporary adhesive for wafer processing No. any one of 1 to 6 to form a wafer laminate; (b) A step of thermally curing the temporary adhesive; (c) A step of grinding or polishing the non-circuit formation surface of the wafer of the wafer laminate; (d) A step of processing the non-circuit formation surface of the wafer; (e) A step of peeling the processed wafer from the support A method for manufacturing a thin wafer including the above steps. 8. A wafer laminate including a support, a temporary adhesive layer obtained from a temporary adhesive for wafer processing No. 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, wherein the temporary adhesive layer is releasably adhered to the surface of the wafer.

Advantages of the Invention

[0010] The temporary adhesive for wafer processing of the present invention uses a thermosetting silicone resin composition containing non-functional organopolysiloxane, so that not only does thermal decomposition of the resin not occur, but also the resin does not flow even at a high temperature of 200 °C or higher, and it has high heat resistance. Therefore, it can be applied to a wide range of semiconductor film formation processes, has excellent CVD (chemical vapor deposition) resistance, and can also form a temporary adhesive layer with high film thickness uniformity on a wafer having steps. Due to this film thickness uniformity, it is possible to easily produce a uniform thin wafer with a thickness of 50 μm or less. Furthermore, since the use of non-functional organopolysiloxane also provides excellent peelability, after producing the thin wafer, the wafer can be easily peeled from the support, for example, at room temperature, and it is possible to easily manufacture a thin wafer that is prone to cracking. In addition, since the temporary adhesive of the present invention can selectively adhere to the support, no residue derived from the temporary adhesive remains on the thin wafer after peeling, and it also has excellent cleaning removability thereafter. According to the method for manufacturing a thin wafer of the present invention, a thin wafer having a through electrode structure or a bump connection structure can be easily manufactured.

Embodiments for Carrying Out the Invention

[0011] [Temporary Adhesive for Wafer Processing] The temporary adhesive for wafer processing of the present invention is composed of a thermosetting silicone resin composition containing non-functional organopolysiloxane. From the viewpoint of applicability to a silicon wafer or the like having steps, a silicone resin composition having good spin coatability is preferably used as the temporary adhesive for wafer processing.

[0012] Such a thermosetting silicone resin composition preferably contains, for example, the following components (A) to (D). (A) Organopolysiloxane having two or more alkenyl groups in one molecule: 100 parts by mass, (B) Organohydrogenpolysiloxane containing hydrogen atoms (SiH groups) bonded to two or more silicon atoms in one molecule: an amount such that the total of the SiH groups in component (B) relative to the total of the alkenyl groups in component (A) is 0.3 to 10 in molar ratio, (C) Non-functional organopolysiloxane: 0.1 to 200 parts by mass, and (D) Hydrosilylation reaction catalyst: 0.1 to 5,000 ppm in terms of the atomic weight of the metal, based on the total mass of components (A), (B) and (C).

[0013] [Component (A)] Component (A) is an organopolysiloxane having two or more alkenyl groups in one molecule. As component (A), there may be mentioned linear or branched diorganopolysiloxanes containing two or more alkenyl groups in one molecule, organopolysiloxanes having a three-dimensional network structure containing two or more alkenyl groups and having siloxane units (Q units) represented by SiO 4 / 2 units, and the like. Among these, diorganopolysiloxanes or organopolysiloxanes having a three-dimensional network structure, in which the alkenyl group content is 0.6 to 9 mol%, are preferred. In the present invention, the alkenyl group content means the ratio (mol%) of the number of alkenyl groups to the number of Si atoms in the molecule.

[0014] Examples of 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. [Chemical formula]

[0015] 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. X 1 ~X 5 are each independently an alkenyl group-containing monovalent organic group.

[0016] In formula (A-1), a and b are each independently an integer of 0 to 3. In formulas (A-1) and (A-2), c 1 , c 2 , d 1 and d 2 are such that 0 ≦ c 1≦10, 2 ≦ c 2 ≦10, 0 ≦ d 1 ≦100 and 0 ≦ d 2 is an integer satisfying ≦100. However, a + b + c 1 ≧2. a, b, c 1 , c 2 , d 1 and d 2 are preferably a combination of numbers such that the alkenyl group content is 0.6 to 9 mol%.

[0017] In formula (A-3), e is an integer from 1 to 3. f 1 , f 2 and f 3 are numbers such that (f 2 + f 3 ) / f 1 is 0.3 to 3.0, and f 3 / (f 1 + f 2 + f 3 ) is 0.01 to 0.6.

[0018] As the monovalent hydrocarbon group other than the aliphatic unsaturated hydrocarbon group, those having 1 to 10 carbon atoms are preferable. For example, alkyl groups such as methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, tert-butyl group, n-pentyl group, n-hexyl group; cycloalkyl groups such as cyclopentyl group, cyclohexyl group; aryl groups such as phenyl group, tolyl group, etc. Among these, alkyl groups such as methyl group or phenyl group are preferable.

[0019] As the alkenyl group-containing monovalent organic group, those having 2 to 10 carbon atoms are preferable. For example, alkenyl groups such as vinyl group, allyl group, hexenyl group, octenyl group; (meth)acryloylalkyl groups such as acryloylpropyl group, acryloylmethyl group, methacryloylpropyl group; (meth)acryloxyalkyl groups such as acryloxypropyl group, acryloxy methyl group, methacryloxypropyl group, methacryloxy methyl group; alkenyl group-containing monovalent hydrocarbon groups such as cyclohexenylethyl group, vinyloxypropyl group. Among these, from an industrial perspective, the vinyl group is preferable.

[0020] In formula (A-1), a and b are each independently an integer from 0 to 3. However, if a is from 1 to 3, the molecular chain end is blocked by an alkenyl group, so it is preferable because the reaction can be completed in a short time by the highly reactive molecular chain end alkenyl group. Also, from the cost aspect, it is industrially preferable that a is 1. The property of the alkenyl group-containing diorganopolysiloxane represented by formula (A-1) or (A-2) is preferably in an oil form or a raw rubber form.

[0021] 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 from 1 to 3, but from the cost aspect, it is industrially preferable that e is 1. Also, the product of the average value of e and f 3 / (f 1 +f 2 +f 3 ) is preferably from 0.02 to 1.5, and more preferably from 0.03 to 1.0. The organopolysiloxane represented by formula (A-3) may be used as a solution dissolved in an organic solvent.

[0022] The number average molecular weight (Mn) of the organopolysiloxane as component (A) is preferably from 100 to 1,000,000, and more preferably from 1,000 to 100,000. If Mn is within the above range, it is preferable in terms of workability associated with the viscosity of the composition and processability associated with the storage elastic modulus after curing. In the present invention, Mn is a polystyrene equivalent measurement value by gel permeation chromatography using toluene as a solvent.

[0023] (A) component may be used alone or in combination of two or more. In particular, it is preferable to use a combination of an organopolysiloxane represented by formula (A-1) and an organopolysiloxane represented by formula (A-3). At this time, 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, based on 100 parts by mass of the organopolysiloxane represented by formula (A-1).

[0024] [Component (B)] (B) component is a crosslinking agent and is an organohydrogenpolysiloxane having at least 2, preferably 3 or more, hydrogen atoms (SiH groups) bonded to silicon atoms in one molecule. The organohydrogenpolysiloxane may be linear, branched or cyclic. Further, the organohydrogenpolysiloxane may be used alone or in combination of two or more.

[0025] The viscosity of the organohydrogenpolysiloxane of component (B) at 25 °C is preferably 1 to 5,000 mPa·s, more preferably 5 to 500 mPa·s. In the present invention, the viscosity is the measured value at 25 °C by a rotational viscometer.

[0026] The Mn of the organohydrogenpolysiloxane of component (B) 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 workability associated with the composition viscosity and processability associated with the storage elastic modulus after curing.

[0027] (Component (B) is preferably blended so that the total of SiH groups in component (B) relative to the total of alkenyl groups in component (A) is in the range of 0.3 to 10 in terms of molar ratio (SiH group / alkenyl group), and more preferably in the range of 1.0 to 8.0. If the molar ratio is 0.3 or more, the crosslinking density will not be low, and problems such as the temporary adhesive layer not curing will not occur. Also, if the molar ratio is 10 or less, the crosslinking density will not be too high, sufficient adhesive strength and tack can be obtained, and the usable time of the treatment liquid can be extended.)

[0028] [(Component (C))] (Component (C) is a non-functional organopolysiloxane. Here, "non-functional" means that it does not have reactive groups such as alkenyl groups, hydrogen atoms, hydroxy groups, alkoxy groups, halogen atoms, and epoxy groups directly or via any group bonded to silicon atoms in the molecule.)

[0029] Examples of such non-functional organopolysiloxanes include organopolysiloxanes having a monovalent hydrocarbon group other than an aliphatic unsaturated hydrocarbon group, which is unsubstituted or substituted and has 1 to 12 carbon atoms, preferably 1 to 10 carbon atoms. Examples of such monovalent hydrocarbon groups include alkyl groups such as methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, and heptyl group; cycloalkyl groups such as cyclohexyl group; aryl groups such as phenyl group, tolyl group, xylyl group, and naphthyl group; aralkyl groups such as benzyl group and phenethyl group. Also, a part or all of the hydrogen atoms of these groups may be substituted with halogen atoms such as chlorine atom, fluorine atom, and bromine atom, and examples of such groups include halogenated alkyl groups such as chloromethyl group, 3-chloropropyl group, and 3,3,3-trifluoropropyl group. The monovalent hydrocarbon group is preferably an alkyl group or an aryl group, and more preferably a methyl group or a phenyl group.)

[0030] (C) The molecular structure of the non-functional organopolysiloxane is not particularly limited and may be linear, branched, cyclic, etc., but linear or branched organopolysiloxanes are preferred. In particular, it is preferably a linear or branched diorganopolysiloxane in which the main chain basically consists of a repetition of diorganosiloxane units and the molecular chain ends are blocked with triorganosiloxy groups.

[0031] (C) The non-functional organopolysiloxane of the component preferably has a viscosity at 25 °C of its 30 mass% toluene solution in the range of 100 to 500,000 mPa·s, more preferably 200 to 100,000 mPa·s, from the viewpoints of the workability of the composition, the coatability on the substrate, the mechanical properties of the cured product, the peelability of the support, etc. Within the above range, since it has an appropriate molecular weight, it will not volatilize when the silicone resin composition is heat-cured and it will be difficult to obtain an effect, nor will it cause wafer cracking in a wafer thermal process such as CVD. Also, since the workability and coatability are good, it is preferred.

[0032] Examples of the linear non-functional organopolysiloxane include a dimethylsiloxane polymer blocked with trimethylsiloxy groups at both ends of the molecular chain, a diphenylpolysiloxane blocked with trimethylsiloxy groups at both ends of the molecular chain, a 3,3,3-trifluoropropylmethylsiloxane polymer blocked with trimethylsiloxy groups at both ends of the molecular chain, a dimethylsiloxane·diphenylsiloxane copolymer blocked with trimethylsiloxy groups at both ends of the molecular chain, a dimethylsiloxane·3,3,3-trifluoropropylmethyl copolymer blocked with trimethylsiloxy groups at both ends of the molecular chain, a diphenylsiloxane·3,3,3-trifluoropropylmethyl copolymer blocked with trimethylsiloxy groups at both ends of the molecular chain, a dimethylsiloxane·3,3,3-trifluoropropylmethylsiloxane·diphenylsiloxane copolymer blocked with trimethylsiloxy groups at both ends of the molecular chain, a dimethylpolysiloxane blocked with triphenylsiloxy groups at both ends of the molecular chain, a diphenylpolysiloxane blocked with triphenylsiloxy groups at both ends of the molecular chain, a dimethylsiloxane·diphenylsiloxane copolymer blocked with triphenylsiloxy groups at both ends of the molecular chain, etc.

[0033] Examples of the branched non-functional organopolysiloxane include those shown below. [Chemical formula]

[0034] [Chemical formula] (In the formula, g1, g2, g3, g4, g5, g1', g2', g3', g4', g5' and g6' are each independently any integer such that the viscosity of a 30% by mass toluene solution of the compound at 25 °C is within the above range.)

[0035] The blending amount of the non-functional organopolysiloxane of component (C) is 0.1 to 200 parts by mass, preferably 1 to 180 parts by mass, and more preferably 10 to 170 parts by mass with respect to 100 parts by mass of component (A). If the blending amount of component (C) is within the above range, the wafer can be easily peeled from the support. The non-functional organopolysiloxane of component (C) may be used alone or in combination of two or more. Further, its property is preferably oily or raw rubber-like.

[0036] [Component (D)] Component (D) is a hydrosilylation reaction catalyst, preferably a platinum group metal-based hydrosilylation reaction catalyst. Component (D) is a catalyst that promotes the addition reaction between the alkenyl group in component (A) and the hydrosilyl group in component (B). Since this hydrosilylation reaction catalyst is generally a compound of a noble metal and is expensive, platinum or a platinum compound that is relatively easily available is often used.

[0037] Examples of the platinum compound include chloroplatinic acid or a complex of chloroplatinic acid and an olefin such as ethylene, a complex with an alcohol or vinylsiloxane, and metallic platinum supported on silica, alumina, carbon, etc. As platinum group metal catalysts other than platinum compounds, rhodium, ruthenium, iridium, and palladium-based compounds are also known. For example, RhCl(PPh3 ) 3 , RhCl(CO)(PPh 3 ) 2 , Ru 3 (CO) 12 , IrCl(CO)(PPh 3 ) 2 , Pd(PPh 3 ) 4 etc. In the above formula, Ph represents a phenyl group.

[0038] When using these catalysts, when it is a solid catalyst, it can be used in a solid state. However, in order to obtain a more uniform cured product, it is preferable to dissolve chloroplatinic acid or a complex in a suitable solvent and make it compatible with the component (A) for use.

[0039] The addition amount of the component (D) is an effective amount, usually 0.1 to 5,000 ppm in terms of the atomic weight of the metal relative to the total mass of the components (A), (B) and (C), preferably 1 to 1,000 ppm. If it is 0.1 ppm or more, the curability of the composition will not decrease, the crosslink density will not decrease, and the holding power will not decrease. If it is 5,000 ppm or less, side reactions such as dehydrogenation during curing can be suppressed, and the usable time of the treatment liquid can also be extended.

[0040] [Component (E)] The thermosetting silicone resin composition may further contain a reaction controller as the component (E). The reaction controller is optionally added as needed to prevent the composition from thickening or gelling when preparing the composition or applying it to a substrate.

[0041] Examples of the reaction controller 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-trimethylsiloxysiloxy-1-hexyne, 1-ethynyl-1-trimethylsiloxysiloxy-1-hexyne, 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane, 1,1,3,3-tetramethyl-1,3-divinyldisiloxane, and the like. Among these, 1-ethynylcyclohexanol and 3-methyl-1-butyn-3-ol are preferred.

[0042] When the thermosetting silicone resin composition contains the component (E), since the control ability varies depending on the chemical structure, its content should be adjusted to an optimal amount respectively. However, in view of the curability, storage stability, and influence on the physical properties after curing, etc., based on 100 parts by mass of the total of the components (A), (B), and (C), it is preferably 0.001 to 10 parts by mass, more preferably 0.01 to 10 parts by mass. If the content of the component (E) is within the above range, the usable time of the composition is long, long-term storage stability can be obtained, and the curability and workability are good.

[0043] The thermosetting silicone resin composition may further contain R A 3 SiO 0.5 units (wherein R A are each independently an unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms.) and SiO 2 units, and an organopolysiloxane having a molar ratio of R 2 units to SiO A 3 SiO 0.5 units (R A 3 SiO 0.5 / SiO 2 ) of 0.3 to 1.8 may be added. The addition amount is preferably 0 to 500 parts by mass based on 100 parts by mass of the component (A).

[0044] In order to further enhance the heat resistance of the temporary adhesive layer to be obtained from the thermosetting silicone resin composition, a filler such as silica may be added within a range that does not impair its performance.

[0045] The thermosetting silicone resin composition may be used after being made into a solution by adding a solvent for reasons such as improving workability and miscibility due to a decrease in the viscosity of the composition, and adjusting the film thickness of the temporary adhesive layer. The solvent to be used is not particularly limited as long as it can dissolve the above components. For example, hydrocarbon solvents such as pentane, hexane, cyclohexane, isooctane, nonane, decane, p-menthane, pinene, isododecane, and limonene are preferable.

[0046] As a method of making it into a solution, after preparing the thermosetting silicone resin composition, a method of finally adding a solvent to adjust it to a desired viscosity, or a method of diluting the highly viscous component (A), (B), and / or (C) with a solvent in advance, improving workability and miscibility, and then mixing the remaining components can be mentioned. Further, as a mixing method when making it into a solution, a mixing method may be appropriately selected and implemented from a shaking mixer, a magnetic stirrer, various mixers, etc., according to the composition viscosity and workability.

[0047] The blending amount of the solvent may be appropriately set from viewpoints such as adjusting the viscosity and workability of the composition and the film thickness of the temporary adhesive layer. For example, it is preferably 5 to 900 parts by mass, more preferably 10 to 400 parts by mass, based on 100 parts by mass of the thermosetting silicone resin composition.

[0048] The temporary adhesive layer can be formed by applying the thermosetting silicone resin composition onto a substrate by a method such as spin coating or roll coating. Among these, when forming the temporary adhesive layer on the substrate by a method such as spin coating, it is preferable to make the thermosetting silicone resin composition into a solution and then coat it.

[0049] The viscosity of the solubilized thermosetting silicone resin composition at 25°C is preferably 1 to 100,000 mPa·s, more preferably 10 to 10,000 mPa·s, from the viewpoint of coatability.

[0050] The 180° peel adhesion of a 25 mm wide test piece (e.g., a glass test piece) at 25°C after curing of the thermosetting silicone resin composition is usually 2 to 50 gf, preferably 3 to 30 gf, and more preferably 5 to 20 gf. If it is 2 gf or more, there is no risk of wafer deviation during wafer grinding, and if it is 50 gf or less, wafer peeling becomes easy.

[0051] The storage modulus of the thermosetting silicone resin composition at 25°C after curing is 1,000 Pa or more and 1,000 MPa or less, preferably 10,000 Pa or more and 100 MPa or less. If the storage modulus is 1,000 Pa or more, the formed film is tough and there is no risk of wafer deviation or accompanying wafer cracking during wafer grinding. If it is 1,000 MPa or less, the deformation stress during wafer thermal processes such as CVD can be relaxed, and it is also stable during thermal processes on the wafer.

[0052] [Method for manufacturing a thin wafer] The method for manufacturing a thin wafer of the present invention is characterized in that the wafer processing temporary adhesive is used for temporarily bonding a wafer having a semiconductor circuit or the like and a support.

[0053] The method for manufacturing a thin wafer of the present invention includes the following steps (a) to (e). [Step (a)] Step (a) is a temporary bonding step, in which 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 is detachably bonded to a support using the wafer processing temporary adhesive to form a wafer laminate.

[0054] Specifically, a temporary adhesive layer can be formed on the surface of the wafer using the temporary adhesive for wafer processing, and temporary adhesion can be achieved by bonding the support and the surface of the wafer through the temporary adhesive layer. Alternatively, a temporary adhesive layer can be formed on the surface of the support using the temporary adhesive for wafer processing, and temporary adhesion can be achieved by bonding the support and the surface of the wafer through the temporary adhesive layer.

[0055] The wafer applicable to the present invention is usually a semiconductor wafer. Examples of the semiconductor wafer include not only silicon wafers but also germanium wafers, gallium-arsenic wafers, gallium-phosphorus wafers, gallium-arsenic-aluminum wafers, and the like. The thickness of the wafer is not particularly limited, but typically it is 600 to 800 μm, more typically 625 to 775 μm.

[0056] As the support, substrates such as silicon wafers, glass plates, and quartz wafers can be used, but are not limited thereto. In the present invention, it is not necessary to irradiate the temporary adhesive layer with radiant energy rays through the support, and the support may not have light transmissibility.

[0057] The temporary adhesive layer may be formed by laminating a film-shaped product of the thermosetting silicone resin composition on a wafer or a support, or may be formed by applying the thermosetting silicone resin composition by a method such as spin coating or roll coating. When the thermosetting silicone resin composition is a solution containing a solvent, after application, depending on the volatilization conditions of the solvent, preferably pre-baked at a temperature of 40 to 200 °C, more preferably 50 to 150 °C, and then used.

[0058] The temporary adhesive layer is preferably formed and used with a film thickness between 0.1 and 500 μm, preferably 1.0 and 200 μm. If the film thickness is 0.1 μm or more, when applying on a substrate, it can be applied entirely without causing uncoated portions. On the other hand, if the film thickness is 500 μm or less, it can withstand the grinding process when forming a thin wafer.

[0059] As a method of bonding the support and the surface of the wafer via the temporary adhesive layer, a method of uniformly pressing under reduced pressure in a temperature range of preferably 40 to 200 °C, more preferably 50 to 150 °C, can be mentioned.

[0060] The pressure when pressing the wafer and the support on which the temporary adhesive layer is formed depends on the viscosity of the temporary adhesive layer, but is preferably 0.01 to 10 MPa, more preferably 0.1 to 1.0 MPa. If the pressure is 0.01 MPa or more, the circuit formation surface and the wafer-support interface can be filled with the temporary adhesive layer. If the pressure is 10 MPa or less, there is no risk of cracking the wafer or deteriorating the flatness of the wafer and the temporary adhesive layer, and subsequent wafer processing is good.

[0061] The bonding of the wafers can be performed using a commercially available wafer bonder, such as EVG520IS, 850TB of EVG, XBS300 of SUSS MicroTec, etc.

[0062] [Step (b)] Step (b) is a step of thermally curing the temporary adhesive layer. After forming the wafer laminate, the temporary adhesive layer is cured by heating preferably at 50 to 300 °C, more preferably 100 to 200 °C, preferably for 1 minute to 4 hours, more preferably for 5 minutes to 2 hours.

[0063] [Step (c)] Step (c) is a step of grinding or polishing the non-circuit formation surface of the wafer temporarily adhered to the support, that is, a step of grinding the back side of the wafer of the wafer laminate obtained in the above step to reduce the thickness of the wafer. There is no particular limitation on the method of grinding the back side of the wafer, and a known grinding method is adopted. Grinding is preferably performed while cooling the wafer and the grindstone (such as diamond) with water. Examples of the apparatus for grinding the back side of the wafer include DAG-810 (trade name) manufactured by DISCO Corporation. Also, the back side of the wafer may be chemically mechanical polished (CMP).

[0064] [Step (d)] Step (d) is a step of performing processing on the non-circuit formation surface of the wafer laminate ground in step (c). That is, it is a step of performing processing on the non-circuit formation surface of the wafer of the wafer laminate thinned by back grinding. This step includes various processes used at the wafer level. Examples include electrode formation, metal wiring formation, protective film formation, etc. More specifically, metal sputtering for forming electrodes etc., wet etching for etching the metal sputtering layer, application of a resist for use as a mask for metal wiring formation, exposure, and pattern formation by development, resist stripping, dry etching, formation of metal plating, silicon etching for TSV formation, formation of an oxide film on the silicon surface, etc., are included among conventionally known processes.

[0065] [Step (e)] Step (e) is a step of peeling the wafer processed in step (d) from the support, that is, a step of peeling the wafer from the support after performing various processes on the thinned wafer and before dicing. This peeling step is generally carried out under relatively mild conditions from room temperature to about 60°C. Examples of the peeling method include a method of horizontally fixing one of the wafer or the support of the wafer laminate and lifting the other at a certain angle from the horizontal direction, a method of attaching a protective film to the ground surface of the ground wafer and peeling the wafer and the protective film from the wafer laminate by a peel method, etc. When performing the peeling step by these peeling methods, it is usually carried out at room temperature.

[0066] Also, step (e) (e1) A step of attaching a dicing tape to the wafer surface of the processed wafer, (e2) A step of vacuum-adsorbing the dicing tape surface to the adsorption surface, and (e3) A step of peeling off the support from the processed wafer by peeling at a temperature in the range of 10 to 100°C of the adsorption surface is preferably included. By doing so, the support can be easily peeled from the processed wafer, and the subsequent dicing step can be easily carried out.

[0067] Also, after step (e), (f) A step 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 may remain on the circuit formation surface of the wafer peeled from the support by step (e), and the removal of the temporary adhesive layer can be performed, for example, by washing the wafer.

[0068] In this step (f), any cleaning liquid that can dissolve the silicone resin of the temporary adhesive layer can be used. Specifically, pentane, hexane, cyclohexane, decane, isononane, p-menthane, pinene, isododecane, limonene, etc. can be mentioned. These solvents may be used alone or in combination of two or more.

[0069] Also, when it is difficult to remove the temporary adhesive layer, bases or acids may be added to the cleaning liquid. As the bases, amines such as ethanolamine, diethanolamine, triethanolamine, triethylamine, ammonia, etc.; ammonium salts such as tetramethylammonium hydroxide can be used. As the acids, organic acids such as acetic acid, oxalic acid, benzenesulfonic acid, dodecylbenzenesulfonic acid can be used. The addition amount of the bases and acids is preferably an amount such that the concentration in the cleaning liquid is 0.01 to 10% by mass, more preferably 0.1 to 5% by mass. Also, in order to improve the removability of the residue, an existing surfactant may be added. Also, the SPIS-TA-CLEANER series (manufactured by Shin-Etsu Chemical Co., Ltd.) available as a wafer cleaner can also be preferably used.

[0070] As a method for cleaning the wafer, there are a method of cleaning with a paddle using the cleaning liquid, a method of spraying and cleaning with a spray, and a method of immersing in a cleaning liquid tank. The temperature during cleaning is preferably 10 to 80°C, more preferably 15 to 65°C. If necessary, after dissolving the temporary adhesive layer with these cleaning liquids, finally rinsing with water or alcohol and drying may be performed.

[0071] The thickness of the thin wafer obtained by the manufacturing method of the present invention is typically 5 to 300 μm, and more typically 10 to 100 μm.

Example

[0072] Hereinafter, Preparation Examples, Comparative Preparation Examples, Examples and Comparative Examples will be shown to more specifically explain the present invention, but the present invention is not limited to these Examples. The viscosity is the measured value at 25 °C using a rotational viscometer.

[0073] [1] Preparation of thermosetting silicone resin solution [Preparation Example 1] To a solution consisting of 100 parts by mass of dimethylpolysiloxane having 2.5 mol% vinyl groups in the molecular side chain and Mn of 30,000 and 200 parts by mass of toluene, SiO 4 / 2 units (Q units) 50 mol%, (CH 3 ) 3 SiO 1 / 2 units (M units) 48 mol% and (CH 2 =CH) 3 SiO 1 / 2 units (Vi units) 2 mol% and consisting of 50 parts by mass of vinylmethylpolysiloxane having Mn of 7,000 and 100 parts by mass of toluene, 230 parts by mass of organohydropolysiloxane having Mn of 2,800 represented by the following formula (M-1), 50 parts by mass of molecular chain both-end trimethylsiloxy group-blocked linear dimethylpolysiloxane with a viscosity (25 °C) of 30,000 mPa·s in a 30% toluene solution and 120 parts by mass of toluene, and 0.6 part by mass of 1-ethynylcyclohexanol were added and mixed. Further, 0.4 part by mass of a hydrosilylation reaction catalyst CAT-PL-5 (manufactured by Shin-Etsu Chemical Co., Ltd., platinum concentration 1.0 mass% (the same hereinafter)) was added thereto, and it was filtered through a 0.2 μm membrane filter to prepare a thermosetting silicone resin solution A1. The viscosity of the resin solution A1 at 25 °C was 230 mPa·s.

Chemical formula

[0074] [Preparation Example 2] 70 parts by mass of dimethylpolysiloxane having 2.5 mol% vinyl groups in the molecular side chains and an Mn of 30,000, 30 parts by mass of dimethylpolysiloxane having 0.15 mol% vinyl groups at both terminal chains and an Mn of 60,000, and 200 parts by mass of toluene. To this solution, 50 parts by mass of a vinylmethylpolysiloxane having an Mn of 7,000 and consisting of 50 mol% SiO 4 / 2 units (Q units), 48 mol% (CH 3 ) 3 SiO 1 / 2 units (M units), and 2 mol% (CH 2 =CH) 3 SiO 1 / 2 units (Vi units), and 100 parts by mass of toluene, 180 parts by mass of an organohydropolysiloxane represented by the formula (M-1) and having an Mn of 2,800, 30 parts by mass of a linear dimethylpolysiloxane blocked with trimethylsiloxy groups at both ends of the molecular chain and having a viscosity (25 °C) of 1,000 mPa·s in a 30% toluene solution, and 0.6 parts by mass of 1-ethynylcyclohexanol were added and mixed. Further, 0.4 parts by mass of a hydrosilylation reaction catalyst CAT-PL-5 was added thereto, and the mixture was filtered through a 0.2 μm membrane filter to prepare a thermosetting silicone resin solution A2. The viscosity of the resin solution A2 at 25 °C was 100 mPa·s.

[0075] [Preparation Example 3] 100 parts by mass of dimethylpolysiloxane having 2.5 mol% vinyl groups at both the terminal and side chains of the molecule and 200 parts by mass of toluene. To this solution, 50 mol% SiO 4 / 2 units (Q units), 48 mol% (CH 3 ) 3 SiO 1 / 2 units (M units), and 48 mol% (CH 2 =CH) 3 SiO 1 / 2A solution consisting of 50 parts by mass of vinylmethylpolysiloxane with Mn of 7,000 and 2 mol% of units (Vi units), and 100 parts by mass of toluene, 230 parts by mass of organohydropolysiloxane with Mn of 2,800 represented by the formula (M-1), a solution consisting of 20 parts by mass of a linear dimethylpolysiloxane blocked at both ends of the molecular chain with trimethylsiloxy groups and having a viscosity (25 °C) of 100,000 mPa·s in a 30% toluene solution and 300 parts by mass of toluene, and 0.6 part by mass of 1-ethynylcyclohexanol were added and mixed. Further, 0.4 part by mass of a hydrosilylation reaction catalyst CAT-PL-5 was added thereto, and the mixture was filtered through a 0.2 μm membrane filter to prepare a thermosetting silicone resin solution A3. The viscosity of the resin solution A3 at 25 °C was 330 mPa·s.

[0076] [Preparation Example 4] To a solution consisting of 100 parts by mass of dimethylpolysiloxane having 2.5 mol% of vinyl groups at both ends and side chains of the molecule and Mn of 30,000 and 200 parts by mass of toluene, SiO 4 / 2 units (Q units) 50 mol%, (CH 3 ) 3 SiO 1 / 2 units (M units) 48 mol% and (CH 2 =CH) 3 SiO 1 / 2 A solution consisting of 200 parts by mass of vinylmethylpolysiloxane with Mn of 7,000 and 2 mol% of units (Vi units), and 400 parts by mass of toluene, 430 parts by mass of organohydropolysiloxane with Mn of 2,800 represented by the formula (M-1), a solution consisting of 100 parts by mass of a linear dimethylpolysiloxane blocked at both ends of the molecular chain with trimethylsiloxy groups and having a viscosity (25 °C) of 30,000 mPa·s in a 30% toluene solution and 120 parts by mass of toluene, and 1.2 parts by mass of 1-ethynylcyclohexanol were added and mixed. Further, 0.8 part by mass of a hydrosilylation reaction catalyst CAT-PL-5 was added thereto, and the mixture was filtered through a 0.2 μm membrane filter to prepare a thermosetting silicone resin solution A4. The viscosity of the resin solution A4 at 25 °C was 120 mPa·s.

[0077] [Preparation Example 5] 70 parts by mass of dimethylpolysiloxane having 2.5 mol% vinyl groups in the molecular side chains and a Mn of 30,000, 30 parts by mass of dimethylpolysiloxane having 0.15 mol% vinyl groups at both terminal chains and a Mn of 60,000, and 200 parts by mass of toluene, to this solution, SiO 4 / 2 unit (Q unit) 50 mol%, (CH 3 ) 3 SiO 1 / 2 unit (M unit) 48 mol% and (CH 2 =CH) 3 SiO 1 / 2 unit (Vi unit) 2 mol% consisting of 200 parts by mass of vinylmethylpolysiloxane having a Mn of 7,000 and 400 parts by mass of toluene, 380 parts by mass of organohydropolysiloxane having a Mn of 2,800 represented by the formula (M-1), 150 parts by mass of a linear dimethylpolysiloxane blocked with trimethylsiloxy groups at both ends of the molecular chain with a viscosity (25 ° C) of 1,000 mPa·s of a 30 mass% toluene solution, and 1.2 parts by mass of 1-ethynylcyclohexanol were added and mixed. Further, 0.8 part by mass of a hydrosilylation reaction catalyst CAT-PL-5 was added thereto, and the mixture was filtered through a 0.2 μm membrane filter to prepare a thermosetting silicone resin solution A5. The viscosity of the resin solution A5 at 25 ° C was 80 mPa·s.

[0078] [Preparation Example 6] To a solution consisting of 100 parts by mass of dimethylpolysiloxane having 2.5 mol% vinyl groups in the molecular side chains and 200 parts by mass of toluene, SiO 4 / 2 unit (Q unit) 50 mol%, (CH 3 ) 3 SiO 1 / 2 unit (M unit) 48 mol% and (CH 2 =CH) 3 SiO 1 / 2A solution consisting of 50 parts by mass of vinyl methyl polysiloxane with Mn of 7,000 and 2 mol% of units (Vi units) and 100 parts by mass of toluene, 230 parts by mass of organohydrogenpolysiloxane with Mn of 2,800 represented by the formula (M-1), a solution consisting of 50 parts by mass of a branched polysiloxane blocked with trimethylsiloxy groups at the molecular chain ends with a viscosity (25 °C) of 50,000 mPa·s in a 30% toluene solution represented by the following formula (M-2) and 120 parts by mass of toluene, and 0.6 part by mass of 1-ethynylcyclohexanol were added and mixed. Further, 0.4 part by mass of a hydrosilylation reaction catalyst CAT-PL-5 was added thereto, and the mixture was filtered through a 0.2 μm membrane filter to prepare a thermosetting silicone resin solution A6. The viscosity of the resin solution A6 at 25 °C was 360 mPa·s. [Chemical formula] (In the formula, k is 60, l is 20, and m is 6,800.)

[0079] [Preparation Example 7] To a solution consisting of 100 parts by mass of dimethylpolysiloxane with Mn of 30,000 having 2.5 mol% of vinyl groups at both ends and side chains of the molecule and 200 parts by mass of toluene, SiO 4 / 2 units (Q units) 50 mol%, (CH 3 ) 3 SiO 1 / 2 units (M units) 48 mol% and (CH 2 =CH) 3 SiO 1 / 2A solution consisting of 200 parts by mass of vinyl methyl polysiloxane with Mn of 7,000 and 2 mol% of units (in Vi units) and 400 parts by mass of toluene, 430 parts by mass of organohydrogenpolysiloxane with Mn of 2,800 represented by formula (M-1), a solution consisting of 100 parts by mass of a branched polysiloxane blocked with trimethylsiloxy groups at the molecular chain ends with a viscosity (25 °C) of 50,000 mPa·s in a 30% by mass toluene solution represented by formula (M-2) and 120 parts by mass of toluene, and 1.2 parts by mass of 1-ethynylcyclohexanol were added and mixed. Further, 0.8 part by mass of a hydrosilylation reaction catalyst CAT-PL-5 was added thereto, and the mixture was filtered through a 0.2 μm membrane filter to prepare a thermosetting silicone resin solution A7. The viscosity of the resin solution A7 at 25 °C was 280 mPa·s.

[0080] [Comparative Preparation Example 1] A thermosetting silicone resin solution CA1 was prepared in the same manner as in Preparation Example 1, except that a solution consisting of 50 parts by mass of a linear dimethylpolysiloxane blocked with trimethylsiloxy groups at both ends of the molecular chain and 120 parts by mass of toluene was not added. The viscosity of the resin solution CA1 at 25 °C was 150 mPa·s.

[0081] [Comparative Preparation Example 2] A thermosetting silicone resin solution CA2 was prepared in the same manner as in Preparation Example 2, except that 30 parts by mass of a linear dimethylpolysiloxane blocked with trimethylsiloxy groups at both ends of the molecular chain was not added. The viscosity of the resin solution CA2 at 25 °C was 180 mPa·s.

[0082] [Comparative Preparation Example 3] A thermosetting silicone resin solution CA3 was prepared in the same manner as in Preparation Example 1, except that 50 parts by mass of a linear dimethylpolysiloxane blocked with trimethylsiloxy groups at both ends of the molecular chain was changed to 50 parts by mass of a polysiloxane containing an epoxy group in the side chain represented by the following formula (M-3) (viscosity (25 °C) of a 30% by mass toluene solution: 33,000 mPa·s). The viscosity of the resin solution CA3 at 25 °C was 260 mPa·s. [Chemical formula]

[0083] [Comparative Preparation Example 4] Thermosetting silicone resin solution CA4 was prepared in the same manner as in Preparation Example 2, except that 30 parts by mass of a linear dimethylpolysiloxane blocked at both ends of the molecular chain with trimethylsiloxy groups was changed to 30 parts by mass of a polysiloxane containing a trimethoxysilyl group in the side chain represented by the following formula (M-4) (viscosity of 30 mass% toluene solution at 25 °C: 2,500 mPa·s). The viscosity of the resin solution CA4 at 25 °C was 190 mPa·s. [Chemical Formula]

[0084] [2] Fabrication and Evaluation of Wafer Stack [Examples 1 to 7 and Comparative Examples 1 to 4] Thermosetting silicone resin solutions A1 to A7 and CA1 to CA4 were spin-coated onto a 200 mm diameter silicon wafer (thickness: 725 μm) having copper posts with a height of 10 μm and a diameter of 40 μm formed on the entire surface, and heated on a hot plate at 100 °C for 2 minutes to form an adhesive layer on the wafer bump formation surface with the film thicknesses shown in Tables 1 and 2 below. Using a 200 mm diameter (thickness: 500 μm) glass plate as a support, the silicon wafer and the glass plate having the adhesive layer were vacuum bonded at 100 °C, 10 -3 mbar or less and a load of 5 kN using a wafer bonding apparatus EVG520IS manufactured by EVG to fabricate a wafer stack. In addition, although a glass plate was used as a support to visually determine abnormalities after substrate bonding, a silicon substrate that does not transmit light such as a wafer can also be used.

[0085] Thereafter, the following tests were performed on the obtained wafer stack. The results are also shown in Tables 1 and 2. The tests were conducted by the following methods.

[0086] (1) Adhesion Test The wafer laminate was heated at 180°C for 1 hour using an oven, cooled to room temperature, and then the adhesion status of the wafer interface was visually checked. If no abnormalities such as bubbles occurred at the interface, it was evaluated as good and indicated by "○", and if abnormalities occurred, it was evaluated as bad and indicated by "×".

[0087] (2) Back grinding resistance test Using the wafer laminate, the back surface of the silicon wafer was ground using a grinder (DAG-810 manufactured by DISCO Corporation) with a diamond grinding wheel. After grinding until the thickness of the substrate reached 50 μm, the presence or absence of abnormalities such as cracks and delamination was examined using an optical microscope (100 times magnification). If no abnormalities occurred, it was evaluated as good and indicated by "○", and if abnormalities occurred, it was evaluated as bad and indicated by "×".

[0088] (3) CVD resistance test (2) After the back grinding resistance test, the wafer laminate was introduced into a CVD apparatus, and a film formation experiment of a 2-μm SiO 2 film was performed, and the presence or absence of appearance abnormalities was examined by visual observation. If no appearance abnormalities occurred, it was evaluated as good and indicated by "○", and if appearance abnormalities such as voids, wafer swelling, and wafer breakage occurred, it was evaluated as bad and indicated by "×". The conditions of the CVD resistance test are as follows. Apparatus name: Plasma CVD, PD270STL manufactured by SAMCO Inc. RF 500W, internal pressure 40 Pa TEOS (tetraethyl orthosilicate): O 2 = 20 sccm: 680 sccm

[0089] (4) Peelability test For the peelability of the substrate, first, a dicing tape (ELP UB-3083D manufactured by Nitto Denko Corporation) was attached to the wafer side of the wafer laminate that had completed the (3) CVD resistance test using a dicing frame, and this dicing tape surface was set on the suction plate by vacuum suction. Then, at room temperature, the glass substrate was peeled off by lifting a point of the glass with tweezers. The case where the 50-μm-thick wafer could be peeled off without being cracked was indicated by "○", and the case where abnormalities such as cracks occurred was evaluated as defective and indicated by "×".

[0090] (5) Cleaning removability test (4) After the peelability test, the 200-mm-diameter wafer (exposed to the CVD resistance test conditions) mounted on the dicing frame through the dicing tape was set on a spin coater with the peeling surface facing up, and SPIS-TA-CLEANER 25 (manufactured by Shin-Etsu Chemical Co., Ltd.) was sprayed as a cleaning solvent for 5 minutes, and then isopropyl alcohol (IPA) was sprayed while rotating the wafer for rinsing. Then, the appearance was observed and the presence or absence of the remaining adhesive was visually checked. Those in which no resin residue was observed were evaluated as good and indicated by "○", and those in which resin residue was observed were evaluated as defective and indicated by "×".

[0091] (6) Peel adhesion force test Thermosetting silicone resin solutions A1 to A7 and CA1 to CA4 were spin-coated on a 200-mm-diameter silicon wafer (thickness: 725 μm), and by heating on a hot plate at 100 °C for 2 minutes, a silicone resin layer was formed on the wafer bump formation surface with the film thicknesses shown in Tables 1 and 2. Then, the silicone resin layer was cured in an oven at 180 °C for 1 hour, and after cooling to room temperature, five 150-mm-long × 25-mm-wide polyimide tapes were attached on the silicone resin layer on the wafer, and the temporary adhesive layer in the portion where the tape was not attached was removed. Using AUTOGRAPH (AG-1) of Shimadzu Corporation, peeling was performed at a speed of 300 mm / min at 25 °C from one end of the tape by 180° for 120 mm, and the average of the forces applied at that time (120-mm stroke × 5 times) was taken as the peel adhesion force of the silicone resin layer.

[0092] (7) Storage Elastic Modulus Measurement Thermosetting silicone resin solutions A1 to A7 and CA1 to CA4 were spin-coated on a glass substrate, respectively, and heated on a hot plate at 100 °C for 2 minutes to form a silicone resin layer on the glass substrate with the film thicknesses shown in Tables 1 and 2. Thereafter, the silicone resin layer was cured in an oven at 180 °C for 1 hour and cooled to room temperature. The glass substrate including the obtained silicone resin layer was sandwiched between 25 mm aluminum plates so that a load of 50 gf was applied to the silicone resin layer, and the elastic modulus was measured at 25 °C and 1 Hz using a rheometer (Ares G2) manufactured by TA Instruments. The obtained value of the storage elastic modulus was taken as the storage elastic modulus of the silicone resin layer.

[0093] [Table 1]

[0094] [Table 2]

[0095] As shown in Tables 1 and 2, the wafer laminates of Examples 1 to 7 including the temporary adhesive layer of the present invention have sufficient processing durability, excellent peelability, and good cleaning removability after peeling. On the other hand, in Comparative Examples 1 to 2 having no functional organopolysiloxane and Comparative Examples 3 to 4 including a functional organopolysiloxane, the wafer with a circuit and the support were strongly adhered, and as a result, wafer cracking occurred in the peeling process and peeling could not be performed.

Claims

1. A temporary adhesive for wafer processing for temporarily adhering a wafer to a support, comprising a thermosetting silicone resin composition containing a non-functional organopolysiloxane, wherein the thermosetting silicone resin composition containing the non-functional organopolysiloxane is (A) 100 parts by mass of an organopolysiloxane having two or more alkenyl groups in one molecule, (B) an organohydrogenpolysiloxane containing hydrogen atoms (SiH groups) bonded to two or more silicon atoms in one molecule: an amount such that the total of the SiH groups in component (B) relative to the total of the alkenyl groups in component (A) is 1.0 to 10 in molar ratio, (C) 10 to 170 parts by mass of a non-functional organopolysiloxane, and (D) a hydrosilylation reaction catalyst: 0.1 to 5,000 ppm in terms of the atomic weight of the metal relative to the total mass of components (A), (B) and (C), a temporary adhesive for wafer processing, wherein the viscosity at 25 °C of a 30% by mass toluene solution of the non-functional organopolysiloxane as component (C) is 200 to 100,000 mPa·s.

2. The temporary adhesive for wafer processing according to claim 1, wherein component (A) contains at least one selected from an organopolysiloxane represented by the following formula (A-1), an organopolysiloxane represented by the following formula (A-2) and an organopolysiloxane represented by the following formula (A-3). 【Chemical Formula 1】 (wherein R 1 ~R 16 are each independently a monovalent hydrocarbon group other than an aliphatic unsaturated hydrocarbon group. X 1 ~X 5 are each independently an alkenyl group-containing monovalent organic group. a and b are each independently an integer of 0 to 3. 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. However, a + b + c 1 ≧ 2. e is an integer of 1 to 3. f 1 , f 2 and f 3 are numbers such that (f 2 + f 3 ) / f 1 becomes 0.3 to 3.0, and f 3 / (f 1 + f 2 + f 3 ) becomes 0.01 to 0.6.)

3. The temporary adhesive for wafer processing according to claim 1 or 2, wherein the thermosetting silicone resin composition containing the non-functional organopolysiloxane further contains, as component (E), a hydrosilylation reaction controller in an amount of 0.001 to 10 parts by mass relative to the total mass of components (A), (B) and (C).

4. The temporary adhesive for wafer processing according to any one of claims 1 to 3, wherein after curing of the thermosetting silicone resin composition containing the non-functional organopolysiloxane, the 180° peel adhesion of a 25 mm wide test piece to a silicon substrate at 25 °C is 2 gf or more and 50 gf or less.

5. The temporary adhesive for wafer processing according to any one of claims 1 to 4, wherein after curing of the thermosetting silicone resin composition containing the non-functional organopolysiloxane, the storage elastic modulus at 25 °C is 1,000 Pa or more and 1,000 MPa or less.

6. Step (a) of removably 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 wafer processing temporary adhesive according to any one of claims 1 to 5 to form a wafer laminate; Step (b) of thermally curing the temporary adhesive; Step (c) of grinding or polishing the non-circuit formation surface of the wafer of the wafer laminate; Step (d) of processing the non-circuit formation surface of the wafer; Step (e) of peeling the processed wafer from the support A method for manufacturing a thin wafer including these steps.

7. A wafer laminate comprising a support, a temporary adhesive layer obtained from the wafer processing temporary adhesive according to any one of claims 1 to 5 laminated thereon, and a wafer having a circuit formation surface on the front surface and a non-circuit formation surface on the back surface, The wafer laminate, wherein the temporary adhesive layer is removably adhered to the surface of the wafer.

Images