Method for manufacturing a wafer processing adhesive, a wafer laminate, and a thin wafer

Abstract

The present invention provides a wafer processing adhesive for temporarily bonding a wafer to a support, comprising a photocurable silicone resin composition containing a non-functional organopolysiloxane, a wafer processing body, and a method for manufacturing a thin wafer using the wafer processing adhesive.

Description

Technology Field

[0001] The present invention relates to a pre-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 realizing even higher density and capacity. Three-dimensional packaging technology is a semiconductor manufacturing technique that thins a single semiconductor chip and stacks it in multiple layers by connecting it via through-silicon vias (TSVs). To achieve this, a process is required to thin a substrate on which semiconductor circuits have been formed by grinding the non-circuit surface (also called the "back side"), and to form electrodes including TSVs on the back side. Conventionally, in the back side grinding process of silicon substrates, a back side protection tape was 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 material; while it is flexible, its strength and heat resistance are insufficient, making it unsuitable for performing TSV formation processes or wiring layer formation processes on the back side.

[0003] Therefore, a system capable of sufficiently withstanding backside grinding, TSV, or backside electrode formation processes has been proposed by bonding a semiconductor substrate to a support such as silicon or glass through an adhesive layer. At this time, the adhesive layer used when bonding the substrate to the support is important. This requires the ability to bond the substrate to the support without gaps, sufficient durability to withstand subsequent processes, and the ability to easily peel off the thin wafer from the support at the end. Since it is peeled off at the end in this manner, this adhesive layer is also referred to as a temporary adhesive layer in this specification.

[0004] Previously known methods for pre-adhesive layers and their peeling include a technique for peeling an adhesive layer from a support by decomposing the adhesive layer through high-intensity light irradiating an adhesive containing a light-absorbing material (Patent Document 1), and a technique for bonding and peeling in a heated, molten state using a heat-meltable hydrocarbon compound in the adhesive (Patent Document 2). The former technique required expensive equipment such as lasers and had problems such as long processing times per substrate. Furthermore, while the latter technique was simple because it was controlled solely by heating, its application range was limited due to insufficient thermal stability at high temperatures exceeding 200°C. Additionally, these pre-adhesive layers were not suitable for forming a uniform film thickness on substrates with high step heights or for achieving complete adhesion to a support.

[0005] Although a technology has been proposed to use a silicone adhesive in the pre-adhesive layer, this involves bonding a substrate to a support using a heat-curing silicone adhesive and separating the substrate from the support by immersing it in an agent that dissolves or decomposes the silicone resin during peeling (Patent Document 3). Consequently, peeling requires a very long time, making it difficult to apply to actual manufacturing processes. Furthermore, cleaning the silicone adhesive remaining as residue on the substrate after peeling also requires a long time, presenting a problem in terms of ease of cleaning. Meanwhile, in the bonding process, heat-curing silicone requires heating to about 150°C, and wafer warping has been a problem, particularly when heating is performed on a hot plate. Therefore, when attempting to bond at a low temperature to suppress wafer warping, there was a problem that it required a long time to complete the curing process. Prior art literature

[0006] Japanese Patent Publication No. 2004-64040, Japanese Patent Publication No. 2006-328104, and U.S. Patent No. 7541264 Specification The problem to be solved

[0007] The present invention aims to provide a pre-adhesive for wafer processing, a wafer laminate, and a method for manufacturing a thin wafer using the same, which leads to improved productivity of thin wafers by enabling bonding of a substrate and a support at a relatively low temperature and in a short time, thereby improving workability and wafer warping during bonding, sufficient substrate retention after bonding even when using a high-step substrate, high process suitability for wafer backside grinding process, TSV formation process, and wafer backside wiring process, excellent wafer thermal process resistance, easy peeling in the peeling process, and excellent residue cleaning of the substrate after peeling. means of solving the problem

[0008] As a result of careful consideration to solve the above problem, the inventors discovered that the problem could be solved by using a photocurable silicone resin composition containing a non-functional organopolysiloxane in a pre-adhesive, and thus completed the present invention.

[0009] Accordingly, the present invention provides a pre-adhesive for wafer processing, a wafer laminate, and a method for manufacturing a thin wafer.

[0010] 1. A temporary adhesive for wafer processing for temporarily bonding a wafer to a support, comprising a photocurable silicone resin composition containing a non-functional organopolysiloxane.

[0011] 2. A photocurable silicone resin composition comprising the above-mentioned non-functional organopolysiloxane

[0012] (A) Organopolysiloxane having two or more alkenyl groups in one molecule: 100 parts by mass,

[0013] (B) Organohydrogenpolysiloxane containing hydrogen atoms (SiH groups) bonded to two or more silicon atoms in one molecule: an amount such that the total number of SiH groups in component (B) is 0.3 to 10 in molar ratio to the total number of alkenyl groups in component (A),

[0014] (C) Non-functional organopolysiloxane: 0.1 to 200 parts by mass, and

[0015] (D) Photoactive hydrosilylation reaction catalyst: 0.1–5,000 ppm in terms of metal atomic weights relative to the total mass of components (A), (B), and (C).

[0016] A temporary adhesive for wafer processing of 1 that includes

[0017] 3. (C) A wafer processing adhesive of 2, wherein the viscosity of a 30 mass% toluene solution of a non-functional organopolysiloxane component is 100 to 500,000 mPa·s at 25°C.

[0018] 4. A pre-adhesive for wafer processing of any one of 1 to 3, wherein the photocurable silicone resin composition containing the above-mentioned non-functional organopolysiloxane also contains 0.001 to 10 parts by mass of a hydrosilylation reaction control agent as component (E) relative to the total mass of components (A), (B), and (C).

[0019] 5. Any one of 1 to 4 of a pre-adhesive for wafer processing, wherein after curing of the photocurable silicone resin composition containing the above-mentioned non-functional organopolysiloxane, the 180° peel strength of a 25 mm wide test specimen on a silicon substrate at 25°C is 2 gf or more and 50 gf or less.

[0020] 6. Any one of 1 to 5 of a pre-adhesive for wafer processing having a storage modulus of 1,000 Pa or more and 1,000 MPa or less at 25°C after curing of a photocurable silicone resin composition containing the above-mentioned non-functional organopolysiloxane.

[0021] 7. A method for manufacturing a thin wafer using a photocurable silicone resin composition containing the non-functional organopolysiloxane, wherein, in a process of bonding and curing a wafer and a support through a pre-adhesive layer (hereinafter, process of (a) and (b)), any one of the following aspects is included. Herein, in any of the aspects, processes (c) to (e) are common.

[0022] (Sun 1)

[0023] (a1) A process of applying any one of the wafer processing adhesive compositions 1 to 6 to the circuit forming surface of a wafer having a circuit forming surface on the front and a circuit non-forming surface on the back, and / or to the bonding surface of a support with the wafer, and bonding.

[0024] (b1) A process for photocuring the adhesive of the bonded wafer above.

[0025] (Sun 2)

[0026] (a2) A process of irradiating light onto any one of the wafer processing adhesive compositions 1 to 6 above.

[0027] (b2) A process of applying a pre-adhesive composition for wafer processing, which has been irradiated with light in (a2), to the circuit-forming surface of a wafer having a circuit-forming surface on the front and a non-circuit-forming surface on the back, and / or to the bonding surface of a support with the wafer, and bonding and curing.

[0028] (c) A process of grinding or polishing the non-circuit surface of the wafer of the above wafer stack.

[0029] (d) A process of performing processing on the non-circuit surface of the wafer.

[0030] (e) A process of peeling the wafer processed above from the support.

[0031] 8. A wafer laminate comprising a support, a pre-adhesive layer obtained from any one of 1 to 6 wafer processing pre-adhesives stacked thereon, and a wafer having a circuit forming surface on the front and a circuit non-forming surface on the back, wherein the pre-adhesive layer is peelably adhered to the surface of the wafer. Effects of the invention

[0032] The wafer processing pre-adhesive of the present invention utilizes a photocurable silicone resin composition containing a non-functional organopolysiloxane, thereby enabling the bonding of substrates at relatively low temperatures and in a short time through light irradiation. As a result, wafer warping during bonding is suppressed, and the bonding time can also be shortened. Furthermore, even after bonding, not only does thermal decomposition of the resin not occur, but the resin does not flow even at high temperatures of 200°C or higher, resulting in high heat resistance. Consequently, it can be applied to a wide range of semiconductor film deposition processes, has excellent CVD (Chemical Vapor Deposition) resistance, and can form a pre-adhesive layer with high film thickness uniformity even on wafers with step heights. Due to this film thickness uniformity, it becomes possible to easily produce uniform thin wafers of 50 μm or less. Additionally, since the use of a non-functional organopolysiloxane provides excellent peelability, the wafer can be easily peeled from a support, for example, at room temperature, after the production of the thin wafer, making it possible to easily produce fragile thin wafers. In addition, since the pre-adhesive of the present invention can selectively adhere to a support, no residue derived from the pre-adhesive remains on the thin wafer after peeling, and subsequent cleaning and removal properties are excellent. 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. Brief explanation of the drawing

[0033] FIG. 1 is an explanatory diagram showing the process of the method for manufacturing a thin wafer of the present invention. Specific details for implementing the invention

[0034] (Form for carrying out the invention)

[0035] [Temporary Adhesive for Wafer Processing]

[0036] The pre-adhesive for wafer processing according to the present invention comprises a photocurable silicone resin composition containing a non-functional organopolysiloxane. Due to its applicability to silicon wafers having steps, a silicone resin composition having good spin-coating properties is suitably used as a pre-adhesive for wafer processing.

[0037] As such a photocurable silicone resin composition, it is preferable that it comprises, for example, the following components (A) to (D).

[0038] (A) Organopolysiloxane having two or more alkenyl groups in one molecule: 100 parts by mass,

[0039] (B) Organohydrogenpolysiloxane containing hydrogen atoms (SiH groups) bonded to two or more silicon atoms in one molecule: an amount such that the total number of SiH groups in component (B) is 0.3 to 10 in molar ratio to the total number of alkenyl groups in component (A),

[0040] (C) Non-functional organopolysiloxane: 0.1 to 200 parts by mass, and

[0041] (D) Photoactive hydrosilylation reaction catalyst: 0.1 to 5,000 ppm in terms of metal atomic weights relative to the total mass of components (A), (B), and (C).

[0042] [(A) Ingredient]

[0043] (A) The component is an organopolysiloxane having two or more alkenyl groups in one molecule. As component (A), a straight-chain or branched organopolysiloxane containing two or more alkenyl groups in one molecule, containing two or more alkenyl groups in one molecule, and SiO4 / Examples include organopolysiloxanes with a three-dimensional network structure having siloxane units (Q units) represented by 2 units. Among these, a diagonopolysiloxane or an organopolysiloxane with a three-dimensional network structure having an alkenyl group content of 0.6 to 9 mol% is preferred. Furthermore, in the present invention, the alkenyl group content refers to the ratio (mol%) of the number of alkenyl groups to the number of Si atoms in the molecule.

[0044] Examples of such organopolysiloxanes include those represented by the following formulas (A-1), (A-2), or (A-3). These may be used individually or in combination of two or more types.

[0045]

[0046] Among equations (A-1) to (A-3), R 1 ~R 16 Each is, independently, a monovalent hydrocarbon group other than an aliphatic unsaturated hydrocarbon group. X 1 ~X 5 Each is independently an alkenyl group-containing monovalent organic group.

[0047] In Equation (A-1), a and b are each independently integers from 0 to 3. In Equations (A-1) and (A-2), c 1 , c 2 , d 1 and d 2 is 0≤c 1 ≤10, 2≤c 2 ≤10, 0≤d 1 ≤100 and 0≤d 2 It is an integer satisfying ≤100. where a+b+c 1 a, b, c ≥2. 1 , c 2 , d 1 and d 2 It is preferable that the number of combinations be equal to the alkenyl group content of 0.6 to 9 mol%.

[0048] In Equation (A-3), e is an integer from 1 to 3. f 1 , f 2and f 3 은 (f 2 +f 3 ) / f 1 This becomes 0.3~3.0, and f 3 / (f 1 +f 2 +f 3 It is a number that is equal to 0.01 to 0.6.

[0049] As a monovalent hydrocarbon group other than the above-mentioned aliphatic unsaturated hydrocarbon group, it is preferable that it has 1 to 10 carbon atoms, and examples include alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, n-pentyl, and n-hexyl groups; cycloalkyl groups such as cyclopentyl and cyclohexyl groups; and aryl groups such as phenyl and tolyl groups. Among these, alkyl groups such as methyl groups or phenyl groups are preferred.

[0050] The above-mentioned alkenyl-containing monovalent organic group is preferably one having 2 to 10 carbon atoms, and examples include alkenyl groups such as vinyl, allyl, hexenyl, and octenyl groups; (meth)acryloylalkyl groups such as acryloylpropyl, acryloylethyl, acryloylmethyl, and methacryloylpropyl groups; (meth)acryloxyalkyl groups such as acryloxypropyl, acryloylethyl, acryloylmethyl, methacryloxypropyl, methacryloxyethyl, and methacryloxymethyl groups; and alkenyl-containing monovalent hydrocarbon groups such as cyclohexenylethyl and vinyloxypropyl groups. Among these, from an industrial perspective, vinyl groups are preferred.

[0051] In formula (A-1), a and b are each independently integers from 0 to 3, but if a and b are 1 to 3, it is preferable because the molecular chain ends are blocked by alkenyl groups, allowing the reaction to be completed in a short time by the highly reactive alkenyl groups at the molecular chain ends. Also, in terms of cost, it is industrially preferable for a and b to be 1. The properties of the alkenyl group-containing dioganopolysiloxane represented by formula (A-1) or (A-2) are preferably oil-like or raw rubber-like.

[0052] The organopolysiloxane represented by formula (A-3) is SiO4 / It includes 2 units and has a three-dimensional network structure. In Equation (A-3), e is an integer ranging from 1 to 3, independently, but it is industrially desirable for it to be 1 in terms of cost. Also, the average value of e and f 3 / (f 1 +f 2 +f 3 It is preferable that the product with ) is 0.02 to 1.5, and more preferable that it is 0.03 to 1.0. The organopolysiloxane represented by formula (A-3) may be used as a solution dissolved in an organic solvent.

[0053] (A) The number average molecular weight (Mn) of the organopolysiloxane of the component is preferably 100 to 1,000,000, and more preferably 1,000 to 100,000. If Mn is within the above range, it is desirable in terms of workability according to the viscosity of the composition and processability according to the storage modulus after curing. In addition, in the present invention, Mn is a polystyrene equivalent measurement value by gel permeation chromatography using toluene as a solvent.

[0054] (A) The component may be used as a single type or in combination of two or more types. In particular, it is preferable to use a combination of the organopolysiloxane represented by formula (A-1) and the organopolysiloxane represented by formula (A-3). At this time, the amount of organopolysiloxane represented by formula (A-3) used is preferably 1 to 1,000 parts by mass and more preferably 10 to 500 parts by mass per 100 parts by mass of the organopolysiloxane represented by formula (A-1).

[0055] [(B) Ingredient]

[0056] (B) The component is a crosslinking agent and is an organohydrogenpolysiloxane having at least two, preferably three or more, hydrogen atoms (SiH groups) bonded to silicon atoms in one molecule. The organohydrogenpolysiloxane may be linear, branched, or cyclic. In addition, the organohydrogenpolysiloxane may be used as a single type or in combination of two or more types.

[0057] (B) The viscosity of the organohydrogenpolysiloxane of component B at 25°C is preferably 1 to 5,000 mPa·s, and more preferably 5 to 500 mPa·s. In addition, in the present invention, the viscosity is a value measured at 25°C using a rotational viscometer.

[0058] (B) The Mn of the organohydrogenpolysiloxane component is preferably 100 to 100,000, and more preferably 500 to 10,000. If Mn is within the above range, it is desirable in terms of workability according to the viscosity of the composition and processability according to the storage modulus after curing.

[0059] It is preferable to formulate component (B) such that the total number of SiH groups in component (B) relative to the total number of alkenyl groups in component (A) is in the range of 0.3 to 10 in terms of molar ratio (SiH groups / alkenyl groups), and it is more preferable to formulate it such that the range is 1.0 to 8.0. If the molar ratio is 0.3 or higher, the crosslinking density does not decrease, and the problem of the adhesive layer not curing does not occur. In addition, if the molar ratio is 10 or lower, the crosslinking density does not become excessively high, sufficient tack and adhesion are obtained, and the usable time of the treatment solution can be extended.

[0060] [(C) Ingredient]

[0061] (C) The component is a non-functional organopolysiloxane. Here, “non-functional” means that the molecule does not have reactive groups such as alkenyl groups, hydrogen atoms, hydroxyl groups, alkoxy groups, halogen atoms, or epoxy groups bonded to silicon atoms directly or through any group.

[0062] Examples of such non-functional organopolysiloxanes include unsubstituted or substituted organopolysiloxanes having monovalent hydrocarbon groups other than aliphatic unsaturated hydrocarbon groups, having 1 to 12 carbon atoms, preferably 1 to 10. Examples of such monovalent hydrocarbon groups include alkyl groups such as methyl, ethyl, propyl, butyl, pentyl, hexyl, and heptyl groups; cycloalkyl groups such as cyclohexyl groups; aryl groups such as phenyl, tolyl, xylyl, and naphthyl groups; and aralkyl groups such as benzyl and phenethyl groups. Additionally, some or all of the hydrogen atoms of these groups may be substituted with halogen atoms such as chlorine, fluorine, and bromine atoms, and examples of such groups include alkyl halide groups such as chloromethyl, 3-chloropropyl, and 3,3,3-trifluoropropyl groups. The above monovalent hydrocarbon group is preferably an alkyl group or an aryl group, and more preferably a methyl group or a phenyl group.

[0063] (C) The molecular structure of the non-functional organopolysiloxane of the component is not particularly limited and may be straight, branched, cyclic, etc., but a straight or branched organopolysiloxane is preferred, and it is preferred to be a straight-chain diagonopolysiloxane in which the main chain is basically composed of repeating diagonosiloxane units and both ends of the molecular chain are blocked by triagonosiloxy groups.

[0064] (C) The component, non-functional organopolysiloxane, has a viscosity (25°C) of 100 to 500,000 mPa·s in a 30 mass% toluene solution, which is preferred from the perspective of workability of the composition, coating ability on a substrate, mechanical properties of the cured product, and peelability of the support, and is more preferred to be 200 to 100,000 mPa·s. Within the above range, it is preferred because it has an appropriate molecular weight, so it does not volatilize when heating and curing the silicone resin composition, making it difficult to obtain the effect, or cause wafer cracking in wafer thermal processes such as CVD, and the workability and coating ability are good.

[0065] The above-mentioned non-functional organopolysiloxane comprises a dimethylsiloxane polymer with trimethylsiloxy groups blocked at both ends of the molecular chain, a phenylmethylpolysiloxane with trimethylsiloxy groups blocked at both ends of the molecular chain, a 3,3,3-trifluoropropylmethylsiloxane polymer with trimethylsiloxy groups blocked at both ends of the molecular chain, a dimethylsiloxane-methylphenylsiloxane copolymer with trimethylsiloxy groups blocked at both ends of the molecular chain, a dimethylsiloxane-3,3,3-trifluoropropylmethyl copolymer with trimethylsiloxy groups blocked at both ends of the molecular chain, a methylphenylsiloxane-3,3,3-trifluoropropylmethyl copolymer with trimethylsiloxy groups blocked at both ends of the molecular chain, a dimethylsiloxane-3,3,3-trifluoropropylmethylsiloxane-methylphenylsiloxane copolymer with trimethylsiloxy groups blocked at both ends of the molecular chain, a dimethylpolysiloxane with dimethylphenylsiloxy groups blocked at both ends of the molecular chain, and a methylphenylpolysiloxane with dimethylphenylsiloxy groups blocked at both ends of the molecular chain. Examples include dimethylsiloxane-methylphenylsiloxane copolymers that block dimethylphenylsiloxane groups at both ends of the molecular chain.

[0066] (C) The non-functional organopolysiloxane of the component may be used as a single type or in combination of two or more types. In addition, it is preferable that the form be oil-like or natural rubber-like.

[0067] [(D) Component]

[0068] Component (D) is a photo-activated hydrosilylation reaction catalyst, and this photo-activated hydrosilylation reaction catalyst is activated by irradiation with light, particularly ultraviolet light with a wavelength of 300 to 400 nm, and is a catalyst that promotes the addition reaction between the alkenyl group in component (A) and the Si-H group in component (B). This promoting effect is temperature-dependent, and a higher promoting effect is obtained at higher temperatures. Therefore, it is desirable to use the catalyst at an ambient temperature of 0 to 200°C, more preferably 10 to 100°C, after light irradiation, in order to complete the reaction within an appropriate reaction time.

[0069] Photoactive hydrosilylation reaction catalysts mainly include platinum group metal catalysts or iron group metal catalysts. Platinum group metal catalysts include platinum, palladium, and rhodium metal complexes, while iron group metal catalysts include nickel, iron, and cobalt iron complexes. Among these, platinum metal complexes are preferred and frequently used because they are relatively easy to obtain and exhibit good catalytic activity.

[0070] In addition, it is desirable for the ligand to exhibit catalytic activity in medium to long wavelength UV light of UV-B to UV-A in order to suppress damage to the wafer. Examples of such ligands include cyclic diene ligands and β-diketonato ligands.

[0071] From the above, as a preferred example of a photoactive hydrosilylation reaction catalyst, a cyclic diene ligand type, for example, (η 5Examples include β-cyclopentadienyl)tri(σ-alkyl)platinum(IV) complexes, particularly specifically (methylcyclopentadienyl)trimethylplatinum(IV), (cyclopentadienyl)trimethylplatinum(IV), (1,2,3,4,5-pentamethylcyclopentadienyl)trimethylplatinum(IV), (cyclopentadienyl)dimethylethylplatinum(IV), (cyclopentadienyl)dimethylacetylplatinum(IV), (trimethylsilylcyclopentadienyl)trimethylplatinum(IV), (methoxycarbonylcyclopentadienyl)trimethylplatinum(IV), (dimethylphenylsilylcyclopentadienyl)trimethylplatinum(IV), etc., and as β-diketonato ligands, β-diketonatoplatinum(II) or platinum(IV) complexes, particularly specifically Examples include trimethyl(acetylacetonato)platinum(IV), trimethyl(3,5-heptanedione)platinum(IV), trimethyl(methylacetoacetate)platinum(IV), bis(2,4-pentanedione)platinum(II), bis(2,4-hexanedionato)platinum(II), bis(2,4-heptanedione)platinum(II), bis(3,5-heptanedione)platinum(II), bis(1-phenyl-1,3-butanedione)platinum(II), bis(1,3-diphenyl-1,3-propanedione)platinum(II), bis(hexafluoroacetylacetonato)platinum(II), etc.

[0072] When using these catalysts, it is possible to use them in a solid form when they are solid catalysts, but to obtain a more uniform cured product, it is preferable to use them dissolved in a suitable solvent in combination with an organopolysiloxane having an alkenyl group of component (A).

[0073] Examples of solvents include isononan, toluene, and 2-(2-butoxyethoxy)ethyl acetate.

[0074] (D) The amount of added component may be an effective amount, but typically, with respect to the total mass of (A), (B), and (C), it is 0.1 to 5,000 ppm as platinum powder (converted to metal atomic weight), 0.5 to 2,000 ppm, and moreover, 1 to 500 ppm. If it is 0.1 ppm or more, the curability of the composition does not decrease, so the crosslinking density does not decrease, nor does the retention power decrease. If it is 0.5% or less, the usable time of the treatment bath can be extended.

[0075] [(E) Ingredients]

[0076] The above photocurable silicone resin composition may also include a reaction control agent as component (E). The reaction control agent is optionally added as needed to prevent the composition from thickening or gelling when preparing the composition or applying it to a substrate.

[0077] Examples of the above reaction control agents include 3-methyl-1-butyn-3-ol, 3-methyl-1-pentyn-3-ol, 3,5-dimethyl-1-hexin-3-ol, 1-ethynylcyclohexanol, 3-methyl-3-trimethylsiloxy-1-butyn, 3-methyl-3-trimethylsiloxy-1-pentyn, 3,5-dimethyl-3-trimethylsiloxy-1-hexin, 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.

[0078] When the above photocurable silicone resin composition includes component (E), the control ability varies depending on the chemical structure, so the content of each component must be adjusted to an optimal amount. However, considering the curability, storage stability, and the influence on physical properties after curing, the content is preferably 0.001 to 10 parts by mass, more preferably 0.01 to 10 parts by mass, with respect to the total mass of components (A), (B), and (C). If the content of component (E) is within the above range, the usable time of the composition is extended, long-term storage stability is obtained, and the curability and workability are good.

[0079] The above photocurable silicone resin composition also includes R A 3SiO0 . 5 units (among the formula, R A Each is independently an unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms) and includes an SiO2 unit, and R for the SiO2 unit A 3SiO0 . 5-unit molar ratio (R A 3SiO 0.5 An organopolysiloxane having a / SiO2) content of 0.3 to 1.8 may be added. The amount added is preferably 0 to 500 parts by mass per 100 parts by mass of component (A). More preferably, it is greater than 0 and up to 300 parts by mass.

[0080] In order to further improve the heat resistance of the adhesive layer obtained therefrom, fillers such as silica may be added to the above-mentioned photocurable silicone resin composition within a range that does not impair its performance.

[0081] The photocurable silicone resin composition may be used by adding a solvent to form a solution for reasons such as improving workability or mixability through the low viscosity of the composition, or adjusting the film thickness of the adhesive layer. The solvent used is not particularly limited as long as it can dissolve the above components, but hydrocarbon-based solvents such as pentane, hexane, cyclohexane, isooctane, nonane, decane, p-mentane, pinene, isododecane, and limonene are preferred.

[0082] As a method of solution formation, a solvent may be added at the end to adjust the viscosity to a desired level after preparing the above-mentioned photocurable silicone resin composition, or a method of diluting high-viscosity components (A), (B), and / or (C) with a solvent in advance to improve workability and mixability, and then mixing the remaining components. In addition, as a mixing method when solution formation, a mixing method suitable for the viscosity of the composition and workability may be selected and carried out, such as a shaking mixer, a magnetic stirrer, or various mixers.

[0083] The amount of solvent can be appropriately set from the perspective of adjusting the viscosity or workability of the composition or the film thickness of the adhesive layer, but for example, it is preferably 5 to 900 parts by mass, more preferably 10 to 400 parts by mass, per 100 parts by mass of the photocurable silicone resin composition.

[0084] A temporary adhesive layer can be formed by applying the above-mentioned photocurable 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 a substrate by a method such as spin coating, it is preferable to coat by dissolving the above-mentioned photocurable silicone resin composition.

[0085] The viscosity of the solution-formed photocurable silicone resin composition at 25°C is preferably 1 to 100,000 mPa·s, and more preferably 10 to 10,000 mPa·s, in terms of applicability.

[0086] The above photocurable silicone resin composition has a 180° peel strength of a 25 mm wide test specimen (e.g., a silicon substrate test specimen) at 25°C after curing, which is typically 2 to 50 gf, preferably 3 to 30 gf, and more preferably 5 to 20 gf. If it is 2 gf or higher, there is no risk of the wafer peeling off during wafer polishing, and if it is 50 gf or lower, the wafer peeling becomes easy.

[0087] The photocurable silicone resin composition has a storage modulus of 1,000 Pa or more and 1,000 MPa or less at 25°C after curing, preferably 10,000 Pa or more and 500 MPa or less. If the storage modulus is 1,000 Pa or more, the formed film is tough, so there is no risk of wafer detachment or wafer cracking occurring during wafer polishing, and if it is 1,000 MPa or less, deformation stress during wafer thermal processes such as CVD can be relieved, and it is stable even during thermal processes on the wafer.

[0088] [Method for manufacturing thin wafers]

[0089] The method for manufacturing a thin wafer according to the present invention is characterized by using a pre-adhesive layer made of a photocurable silicone resin composition as an adhesive layer between a wafer having semiconductor circuits, etc. and a support, and two embodiments thereof and schematic descriptions thereof are shown in FIG. 1. In either embodiment, the thickness of the thin wafer obtained by the manufacturing method of the present invention is typically 5 to 300 μm, more typically 10 to 100 μm.

[0090] The method for manufacturing a thin wafer according to the present invention has the following processes (a1) to (e) as a first aspect. Additionally, if necessary, it has the processes (f) to (i).

[0091] [Process (a1)]

[0092] Process (a1) is a temporary bonding process, wherein the circuit-forming surface of a wafer having a circuit-forming surface on the front and a circuit-non-forming surface on the back is peelably bonded to a support using the wafer processing temporary bonding agent, and a wafer laminate is formed.

[0093] 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 wafer processing temporary adhesive and bonding the support and the surface of the wafer through the temporary adhesive layer; a method of forming a temporary adhesive layer on the surface of the support using the wafer processing temporary adhesive and bonding the support and the surface of the wafer through the temporary adhesive layer; or a method of forming a temporary adhesive layer on both the surface of the wafer and the surface of the support using the wafer processing temporary adhesive and bonding the support and the surface of the wafer through the temporary adhesive layer.

[0094] A wafer applicable to the present invention is typically a semiconductor wafer. Examples of the semiconductor wafer include not only a silicon wafer, but also a germanium wafer, a gallium-arsenide wafer, a gallium-phosphorus wafer, a gallium-arsenide-aluminum wafer, etc. The thickness of the wafer is not particularly limited, but is typically 600 to 800 μm, and more typically 625 to 775 μm.

[0095] In the first aspect of the present invention, since light irradiation of the photocurable silicone resin composition is performed by passing through a support, a light-transmitting substrate such as a glass plate, a quartz plate, an acrylic plate, a polycarbonate plate, or a polyethylene terephthalate plate may be used as the support. Among these, a glass plate is preferred because it transmits ultraviolet light and also has excellent heat resistance.

[0096] The pre-adhesive layer may be formed by laminating a film-shaped photocurable silicone resin composition onto a wafer or support, or by applying the photocurable silicone resin composition by methods such as spin coating or roll coating. If the photocurable silicone resin composition is a solution containing a solvent, after application, it is provided for use after pre-baking at a temperature preferably 20 to 200°C, more preferably 30 to 150°C, depending on the volatilization conditions of the solvent.

[0097] The above-mentioned adhesive layer is preferably formed and used with a film thickness of 0.1 to 500 μm, preferably between 1.0 and 200 μm. If the film thickness is 0.1 μm or more, when applied to a substrate, it can be applied to the entire surface without creating any uncoated areas. On the other hand, if the film thickness is 500 μm or less, it can withstand the grinding process when forming a thin wafer.

[0098] As a method for bonding the surface of the support and the wafer through the above adhesive layer, preferably, a method of uniformly pressing under reduced pressure in a temperature range of 0 to 200°C, more preferably 20 to 100°C may be cited.

[0099] The pressure applied when compressing the wafer and support having the pre-adhesive layer formed thereon depends on the viscosity of the pre-adhesive layer, but is preferably 0.01 to 10 MPa, more preferably 0.05 to 1.0 MPa. If the pressure is 0.01 MPa or higher, the circuit forming surface or the space between the wafer and the support can be filled with the pre-adhesive layer, and if the pressure is 10 MPa or lower, there is no risk of cracking of the wafer or deterioration of the flatness of the wafer and the pre-adhesive layer, so subsequent wafer processing is good.

[0100] Wafer bonding can be performed using commercially available wafer bonders, such as EVG’s EVG520IS, 850TB, SUSS MicroTec’s XBS300, etc.

[0101] [Process (b1)]

[0102] Process (b1) is a process for photocuring a pre-adhesive layer. After the wafer processed body (laminated substrate) is formed, light is irradiated from the side of a light-transmitting support to photocur the pre-adhesive layer. The active light species at that time is not particularly limited, but ultraviolet light is preferred, and it is even more preferred to be ultraviolet light with a wavelength of 300-400 nm. The ultraviolet irradiation dose (illumination) is 100 mJ / cm² as an integrated light dose. 2 ~100,000 mJ / cm² 2 , preferably 500 mJ / cm² 2 ~10,000 mJ / cm² 2 , more preferably 1,000 to 5,000 mJ / cm² 2 It is desirable to have good curability. If the UV irradiation dose (irradiance) is above the above range, sufficient energy is obtained to activate the photoactive hydrosilylation reaction catalyst in the adhesive layer, and a sufficiently cured product can be obtained. On the other hand, if the UV irradiation dose (irradiance) is below the above range, sufficient energy is irradiated to the composition, so that decomposition of components in the polymer layer does not occur or some of the catalyst is deactivated, and a sufficiently cured product can be obtained.

[0103] The ultraviolet irradiation may be light having multiple emission spectra or light having a single emission spectrum. In addition, the single emission spectrum may have a broad spectrum in the 300 nm to 400 nm range. 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 (UV LEDs) or ultraviolet light-emitting semiconductor device light sources such as ultraviolet light-emitting semiconductor lasers.

[0104] Examples of light sources that irradiate light having multiple emission spectra include metal halide lamps, xenon lamps, carbon arc lamps, chemical lamps, sodium lamps, low-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, gas lasers such as nitrogen, liquid lasers of organic dye solutions, and solid-state lasers containing rare earth ions in an inorganic single crystal.

[0105] When the light has a peak in the wavelength region shorter than 300 nm in the emission spectrum, or when there is a wavelength in the wavelength region shorter than 300 nm that has an irradiance greater than 5% of the irradiance of the maximum peak wavelength in the emission spectrum (for example, when the emission spectrum is broad across a wide wavelength range), and when a substrate such as a quartz wafer that is light-transmittable even to wavelengths shorter than 300 nm is used as the support, it is desirable to remove light of wavelengths in the wavelength region shorter than 300 nm by an optical filter in order to obtain a sufficiently cured product. By doing so, the irradiance of each wavelength in the wavelength region shorter than 300 nm is set to 5% or less of the irradiance of the maximum peak wavelength, preferably 1% or less, more preferably 0.1% or less, and even more preferably 0%. In addition, when there are multiple peaks in the wavelength region between 300 nm and 400 nm in the emission spectrum, the peak wavelength exhibiting the maximum absorbance among them is set as the maximum peak wavelength. Optical filters that block wavelengths shorter than 300 nm are not particularly limited and any known filters may be used. For example, a 365 nm bandpass filter can be used. In addition, the irradiance and spectral distribution of ultraviolet light can be measured using a spectroradiometer, for example, the USR-45d (Ushio Denki).

[0106] Although there are no specific limitations on the light irradiation device, for example, a spot irradiation device, a surface irradiation device, a line irradiation device, a conveyor irradiation device, etc., can be used.

[0107] When curing the photocurable silicone resin composition of the present invention, the light irradiation time cannot be uniformly specified as it varies depending on the illuminance; however, if the illuminance is adjusted 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 pose a particular problem in the work process. In addition, the photocurable silicone resin composition subjected to light irradiation gels after 1 to 120 minutes of irradiation, particularly after 5 to 60 minutes. Furthermore, in the present invention, gelation refers to a state in which the curing reaction of the photocurable silicone resin composition has partially proceeded and the composition has lost its fluidity.

[0108] [Process (c)]

[0109] Process (c) is a process of grinding or polishing the non-circuit forming surface of a wafer temporarily bonded to a support, that is, a process of grinding the back side of the wafer of the wafer stack obtained in the above process and reducing the thickness of the wafer. There are no particular restrictions on the method of grinding the back side of the wafer, and known grinding methods are employed. It is preferable to perform grinding while cooling by spraying water onto the wafer and the grinding wheel (diamond, etc.). Examples of devices for grinding the back side of the wafer include the DAG-810 (product name) manufactured by DISCO Inc. Alternatively, the back side of the wafer may be subjected to chemical mechanical polishing (CMP).

[0110] [Process (d)]

[0111] Process (d) is a process of performing processing on the non-circuit surface of a wafer laminate that has been ground in process (c). That is, it is a process of performing processing on the non-circuit surface of a wafer laminate that has been thinned by back-side grinding. This process includes various processes used at the wafer level. Examples include electrode formation, metal wiring formation, and protective film formation. More specifically, conventional known processes include metal sputtering for forming electrodes, wet etching for etching the metal sputtering layer, application of a resist to serve as a mask for metal wiring formation, formation of a pattern by exposure and development, peeling of the resist, dry etching, formation of metal plating, silicon etching for TSV formation, and formation of an oxide film on the silicon surface.

[0112] [Process (e)]

[0113] Process (e) is a process of peeling the wafer processed in process (d) from the support, that is, a process of peeling the wafer from the support before dicing after performing various processes on the thinned wafer. This peeling process is generally carried out under relatively mild conditions ranging from room temperature to about 60°C. Examples of peeling methods include a method of fixing one side of the wafer or support of the wafer stack horizontally and lifting the other side at a certain angle from the horizontal direction, a method of immersing the wafer stack in a solvent beforehand to swell the adhesive layer and then performing peel peeling as described above, and 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 stack by peeling. When the peeling process is carried out using these peeling methods, it is usually carried out at room temperature.

[0114] Also, process (e)

[0115] (e1) A process of attaching dicing tape to the wafer surface of a processed wafer,

[0116] (e2) A process of vacuum adsorbing the dicing tape surface onto the adsorption surface, and

[0117] (e3) A process of peeling off the support from the processed wafer at a temperature of 10 to 100°C on the adsorption surface.

[0118] It is desirable to include [this]. By doing so, the support can be easily peeled off from the wafer that has undergone processing, and the subsequent dicing process can be easily performed.

[0119] Also, after process (e),

[0120] (f) Process of removing the temporary adhesive layer remaining on the circuit forming surface of the peeled wafer

[0121] It is desirable to perform the following. In some cases, a temporary adhesive layer may remain on the circuit forming surface of the wafer peeled from the support by process (e), and the removal of this temporary adhesive layer can be performed, for example, by cleaning the wafer.

[0122] In this process (f), any cleaning solution capable of dissolving the silicone resin of the adhesive layer can be used, specifically, pentane, hexane, cyclohexane, decane, isononane, p-mentane, pinene, isododecane, limonene, etc. These solvents may be used individually or in combination of two or more types.

[0123] In addition, if it is difficult to remove the adhesive layer, bases or acids may be added to the cleaning solution. As bases, amines such as ethanolamine, diethanolamine, triethanolamine, triethylamine, and ammonia; and ammonium salts such as tetramethylamnonium hydroxide may be used. As acids, organic acids such as acetic acid, oxalic acid, benzenesulfonic acid, and dodecylbenzenesulfonic acid may be used. The amount of bases or acids added is such that the concentration in the cleaning solution is preferably 0.01 to 10 mass%, more preferably 0.1 to 5 mass%. In addition, to improve the removal of residues, conventional surfactants may be added. Also, the SPIS-TA-CLEANER series (manufactured by Shin-Etsu Kagaku Kogyo Co., Ltd.), which is available as a wafer cleaning agent, may be suitably used.

[0124] As cleaning methods for the wafer, cleaning with a pudding using the cleaning solution, cleaning with a spray, or immersion in a cleaning solution bath may be used. The temperature during cleaning is preferably 10 to 80°C, more preferably 15 to 65°C, and if necessary, after dissolving the adhesive layer with these cleaning solutions, a final rinsing with water or alcohol may be performed, followed by a drying treatment.

[0125] As a second aspect of the method for manufacturing a thin wafer according to the present invention, the processes of (a2) and (b2) below are described. The processes of (b2) and below, namely (c) to (e), preferably (c) to (f), are identical to the first aspect above.

[0126] [Process (a2)]

[0127] Process (a2) is a process of forming a photocurable silicon resin composition layer on a wafer and / or a support by irradiating light.

[0128] Unlike the first embodiment, in which light irradiation is performed after bonding the wafer and the support, light irradiation is performed on the photocurable silicon resin composition before bonding, thereby eliminating the need for a light irradiation process that passes through the support, and consequently, light transmittance is not required for the support. Therefore, according to this embodiment, in addition to the above-mentioned examples of support applications, substrates that do not transmit light, such as silicon, aluminum, SUS, copper, germanium, gallium-arsenide, gallium-phosphorus, and gallium-arsenide-aluminum, can also be applied as supports. Furthermore, according to this method, the effect of curing inhibition from the wafer can be reduced, so the range of wafer applications can be expanded.

[0129] Regarding the application of a photocurable silicone resin composition that has undergone light irradiation, [1] a wafer [2] a support [3] can be applied to either the wafer or the support.

[0130] Regarding the method of performing light irradiation on a photocurable silicone resin composition before bonding, examples may include a method of applying the composition onto a wafer and / or a support while performing light irradiation on the composition, a method of applying the composition onto a wafer and / or a support after performing light irradiation on the entire composition, and a method of performing light irradiation after applying the composition onto a wafer and / or a support, but there are no particular limitations, and the method may be appropriately selected and performed considering workability. In addition, regarding the active light species, ultraviolet irradiation amount (illumination), light source, emission spectrum, light irradiation device, and light irradiation time for light irradiation, the method described in [Process (b1)] of the first embodiment may be used.

[0131] The method for forming the first and second temporary adhesive layers can be performed in the same manner as in the first embodiment, and a film, or a corresponding composition or solution thereof, can be formed on a wafer and / or a support by a method such as spin coating or a roll coater. When used as a solution, after spin coating, depending on the volatile conditions of the solvent, it is provided for use after pre-baking at a temperature of 20 to 200°C, preferably 30 to 150°C.

[0132] [Process (b2)]

[0133] Process (b2) is a process of bonding a circuit forming wafer and / or a support having a photocurable silicon resin composition layer formed in process (a2) under vacuum conditions. At this time, preferably in a temperature range of 0 to 200°C, more preferably 20 to 100°C, and by uniformly pressing the substrate under reduced pressure (vacuum) at this temperature, a wafer processing body (laminated substrate) in which the wafer is bonded to the support is formed. Here, the same as that of the first embodiment can be used as the wafer bonding device.

[0134] Examples

[0135] The present invention will be explained more specifically below by presenting preparation examples, comparative preparation examples, examples, and comparative examples, but the present invention is not limited to these examples. In addition, viscosity is a value measured at 25°C using a TVB-10M type rotational viscometer (manufactured by Toki Sangyo Co., Ltd.).

[0136] [1] Preparation of photocurable silicone resin solution

[0137] [Preparation Example 1]

[0138] In a solution comprising 100 parts by mass of dimethylpolysiloxane having 2.5 mol% vinyl groups in the molecular side chain and containing 30,000 Mn, and 200 parts by mass of toluene, SiO4 / 2 Unit (Q unit) 50 mol%, (CH3)3SiO 1 / 2 Units (M units) 48 mol% and (CH2=CH)3SiO1 / 2A solution comprising 50 parts by mass of vinylmethylpolysiloxane with 7,000 Mn and 2 mol% in units (Vi units) and 100 parts by mass of toluene, 230 parts by mass of organohydrogenpolysiloxane with 2,800 Mn represented by the following formula (M-1), a solution comprising 50 parts by mass of dimethylpolysiloxane with trimethylsiloxy group blocking at both ends of the molecular chain and 120 parts by mass of toluene, wherein the viscosity (at 25°C) of the 30 mass% toluene solution is 30,000 mPa·s, and 0.6 parts by mass of 1-ethynylcyclohexanol were added and mixed. Additionally, a photoactive hydrosilylation reaction catalyst was added thereto; 0.4 parts by mass of a toluene solution of (methylcyclopentadienyl)trimethylplatinum(IV) (platinum concentration 1.0 mass%) was added and filtered through a 0.2 μm membrane filter to prepare a photocurable silicone resin solution A1. The viscosity of resin solution A1 at 25°C was 230 mPa·s.

[0139]

[0140] [Jojeye 2]

[0141] In a solution comprising 70 parts by mass of dimethylpolysiloxane having 2.5 mol% vinyl groups in the molecular side chains and Mn 30,000, 30 parts by mass of dimethylpolysiloxane having 0.15 mol% vinyl groups in both end chains and Mn 60,000, and 200 parts by mass of toluene, SiO4 / 2 Unit (Q unit) 50 mol%, (CH3)3SiO 1 / 2 Units (M units) 48 mol% and (CH2=CH)3SiO1 / 2A solution comprising 50 parts by mass of vinylmethylpolysiloxane with 7,000 Mn and 2 mol% in units (Vi units) and 100 parts by mass of toluene, 180 parts by mass of organohydrogenpolysiloxane with 2,800 Mn represented by formula (M-1), 30 parts by mass of dimethylpolysiloxane with trimethylsiloxy group blocking at both ends of the molecular chain, having a viscosity (at 25°C) of 1,000 mPa·s of a 30 mass% toluene solution, and 0.6 parts by mass of 1-ethynylcyclohexanol were added and mixed. Additionally, a photoactive hydrosilylation reaction catalyst was added thereto; 0.4 parts by mass of a toluene solution of (methylcyclopentadienyl)trimethylplatinum(IV) (platinum concentration 1.0 mass%) was added and filtered through a 0.2 μm membrane filter to prepare a photocurable silicone resin solution A2. The viscosity of resin solution A2 at 25°C was 100 mPa·s.

[0142] [Joje-ye 3]

[0143] In a solution comprising 100 parts by mass of dimethylpolysiloxane having 2.5 mol% vinyl groups at both ends of the molecule and side chains, and 200 parts by mass of toluene containing 30,000 Mn, SiO4 / 2 Unit (Q unit) 50 mol%, (CH3)3SiO1 / 2 Units (M units) 48 mol% and (CH2=CH)3SiO1 / 2A solution comprising 50 parts by mass of vinylmethylpolysiloxane with 7,000 Mn and 2 mol% in units (Vi units) and 100 parts by mass of toluene, 230 parts by mass of organohydrogenpolysiloxane with 2,800 Mn represented by formula (M-1), 20 parts by mass of dimethylpolysiloxane blocking trimethylsiloxy groups at both ends of the molecular chain, having a viscosity (at 25°C) of 100,000 mPa·s of a 30 mass% toluene solution, and 300 parts by mass of toluene, and 0.6 parts by mass of 1-ethynylcyclohexanol were added and mixed. Additionally, a photoactive hydrosilylation reaction catalyst was added thereto; 0.4 parts by mass of a toluene solution of (methylcyclopentadienyl)trimethylplatinum(IV) (platinum concentration 1.0 mass%) was added and filtered through a 0.2 μm membrane filter to prepare a photocurable silicone resin solution A3. The viscosity of resin solution A3 at 25°C was 330 mPa·s.

[0144] [Jojeye 4]

[0145] In a solution comprising 100 parts by mass of dimethylpolysiloxane having 2.5 mol% vinyl groups at both ends of the molecule and side chains, and 200 parts by mass of toluene containing 30,000 Mn, SiO4 / 2 Unit (Q unit) 50 mol%, (CH3)3SiO1 / 2 Units (M units) 48 mol% and (CH2=CH)3SiO1 / 2A solution comprising 200 parts by mass of vinylmethylpolysiloxane with 7,000 Mn and 2 mol% in units (Vi units) and 400 parts by mass of toluene, 430 parts by mass of organohydrogenpolysiloxane with 2,800 Mn represented by formula (M-1), 100 parts by mass of dimethylpolysiloxane blocking trimethylsiloxy groups at both ends of the molecular chain, having a viscosity (at 25°C) of 30,000 mPa·s of a 30 mass% toluene solution and 120 parts by mass of toluene, and 1.2 parts by mass of 1-ethynylcyclohexanol were added and mixed. Additionally, a photoactive hydrosilylation reaction catalyst was added thereto; 0.8 parts by mass of a toluene solution of (methylcyclopentadienyl)trimethylplatinum(IV) (platinum concentration 1.0 mass%) was added and filtered through a 0.2 μm membrane filter to prepare a photocurable silicone resin solution A4. The viscosity of resin solution A4 at 25°C was 120 mPa·s.

[0146] [Preparation Example 5]

[0147] In a solution comprising 70 parts by mass of dimethylpolysiloxane having 2.5 mol% vinyl groups in the molecular side chains and Mn 30,000, 30 parts by mass of dimethylpolysiloxane having 0.15 mol% vinyl groups in both end chains and Mn 60,000, and 200 parts by mass of toluene, SiO4 / 2 Unit (Q unit) 50 mol%, (CH3)3SiO 1 / 2 Units (M units) 48 mol% and (CH2=CH)3SiO1 / 2A solution comprising 200 parts by mass of vinylmethylpolysiloxane with 7,000 Mn and 2 mol% in units (Vi units) and 400 parts by mass of toluene, 380 parts by mass of organohydrogenpolysiloxane with 2,800 Mn represented by formula (M-1), 150 parts by mass of dimethylpolysiloxane with trimethylsiloxy group blocking at both ends of the molecular chain, having a viscosity (at 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. Additionally, a photoactive hydrosilylation reaction catalyst was added thereto; 0.8 parts by mass of a toluene solution of (methylcyclopentadienyl)trimethylplatinum(IV) (platinum concentration 1.0 mass%) was added and filtered through a 0.2 μm membrane filter to prepare a photocurable silicone resin solution A5. The viscosity of resin solution A5 at 25°C was 80 mPa·s.

[0148] [Jojeye 6]

[0149] In a solution comprising 100 parts by mass of dimethylpolysiloxane having 2.5 mol% vinyl groups at both ends of the molecule and side chains, and 200 parts by mass of toluene containing 30,000 Mn, SiO4 / 2 Unit (Q unit) 50 mol%, (CH3)3SiO1 / 2 Units (M units) 48 mol% and (CH2=CH)3SiO1 / 2A solution comprising 50 parts by mass of vinylmethylpolysiloxane with 7,000 Mn and 2 mol% in units (Vi units) and 100 parts by mass of toluene, 230 parts by mass of organohydrogenpolysiloxane with 2,800 Mn represented by formula (M-1), a solution comprising 50 parts by mass of dimethylpolysiloxane with trimethylsiloxy group blocking at both ends of the molecular chain and 120 parts by mass of toluene, wherein the viscosity (at 25°C) of the 30 mass% toluene solution is 30,000 mPa·s, and 0.6 parts by mass of 1-ethynylcyclohexanol were added and mixed. Additionally, a photoactive hydrosilylation reaction catalyst was added thereto; 0.8 parts by mass of 2-(2-butoxyethoxy)ethyl acetic acid solution of bis(2,4-heptaneto)platinum(II) (platinum concentration 0.5 mass%) was added and filtered through a 0.2 μm membrane filter to prepare a photocurable silicone resin solution A6. The viscosity of resin solution A6 at 25°C was 230 mPa·s.

[0150] [Jojeye 7]

[0151] In a solution comprising 70 parts by mass of dimethylpolysiloxane having 2.5 mol% vinyl groups in the molecular side chains and Mn 30,000, 30 parts by mass of dimethylpolysiloxane having 0.15 mol% vinyl groups in both end chains and Mn 60,000, and 200 parts by mass of toluene, SiO4 / 2 Unit (Q unit) 50 mol%, (CH3)3SiO 1 / 2 Units (M units) 48 mol% and (CH2=CH)3SiO1 / 2A solution comprising 200 parts by mass of vinylmethylpolysiloxane with 7,000 Mn and 2 mol% in units (Vi units) and 400 parts by mass of toluene, 380 parts by mass of organohydrogenpolysiloxane with 2,800 Mn represented by formula (M-1), 150 parts by mass of dimethylpolysiloxane with trimethylsiloxy group blocking at both ends of the molecular chain, having a viscosity (at 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. Additionally, a photoactive hydrosilylation reaction catalyst was added thereto; 1.6 parts by mass of 2-(2-butoxyethoxy)ethyl acetic acid solution of bis(2,4-heptaneto)platinum(II) (platinum concentration 0.5 mass%) was added and filtered through a 0.2 μm membrane filter to prepare a photocurable silicone resin solution A7. The viscosity of resin solution A7 at 25°C was 80 mPa·s.

[0152] [Comparative Preparation Example 1]

[0153] A thermosetting silicone resin solution CA1 was prepared in the same manner as in Preparation Example 1, except that 0.4 parts by weight of a toluene solution (platinum concentration 1.0 mass%) of (methylcyclopentadienyl)trimethylplatinum(IV), a photoactive hydrosilylation reaction catalyst, was changed to 0.4 parts by weight of a thermally active hydrosilylation reaction catalyst; CAT-PL-5 (manufactured by Shin-Etsu Kagaku Kogyo Co., Ltd., platinum concentration 1.0 mass%). The viscosity of the resin solution CA1 at 25°C was 230 mPa·s.

[0154] [Comparative Preparation Example 2]

[0155] A photocurable silicone resin solution CA2 was prepared in the same manner as in Preparation Example 1, except that a solution consisting of 50 parts by mass of dimethylpolysiloxane blocking 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 CA2 at 25°C was 150 mPa·s.

[0156] [Comparative Preparation Example 3]

[0157] A photocurable silicone resin solution CA3 was prepared in the same manner as in Preparation Example 2, except that 30 parts by mass of dimethylpolysiloxane blocking trimethylsiloxy groups at both ends of the molecular chain were not added. The viscosity of the resin solution CA3 at 25°C was 180 mPa·s.

[0158] [Comparative Preparation Example 4]

[0159] A photocurable silicone resin solution CA4 was obtained in the same manner as in Preparation Example 1, except that 50 parts by mass of dimethylpolysiloxane containing trimethylsiloxy groups blocked at both ends of the molecular chain was replaced with 50 parts by mass of polysiloxane containing epoxy groups in the side chain represented by the following formula (M-2) (viscosity of 30 mass% toluene solution (25°C): 33,000 mPa·s). The viscosity of the resin solution CA4 at 25°C was 260 mPa·s.

[0160]

[0161] [Comparative Preparation Example 5]

[0162] A photocurable silicone resin solution CA5 was obtained in the same manner as in Preparation Example 2, except that 30 parts by mass of dimethylpolysiloxane containing trimethylsiloxy groups blocked at both ends of the molecular chain was replaced with 30 parts by mass of polysiloxane containing trimethoxysilyl groups in the side chain represented by the following formula (M-3) (viscosity of 30 mass% toluene solution (25°C): 2,500 mPa·s). The viscosity of the resin solution CA5 at 25°C was 190 mPa·s.

[0163]

[0164] [2] Fabrication and evaluation of wafer laminates

[0165] [Examples 1–7 and Comparative Examples 1–5]

[0166] On 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 across its entire surface, curable silicone resin solutions A1–A7 and CA1–CA5 were spin-coated, respectively, and heated on a hot plate at 100°C for 2 minutes to deposit a pre-adhesive layer on the wafer bump-forming surface with the film thickness shown in Table 1 below. Using a glass plate with a diameter of 200 mm (thickness: 500 µm) as a support, the silicon wafer having the pre-adhesive layer and the glass plate were each bonded using EVG’s wafer bonding device EVG520IS at 25°C and 10 - 3 Vacuum bonding was performed with a load of 5 kN and a pressure of less than mbar. Afterwards, a wafer laminate was fabricated by irradiating a curable silicone resin composition layer with light using a surface irradiation type UV-LED (wavelength 365 nm) irradiator under the conditions shown in Table 1. In addition, for a sample using a thermosetting silicone resin solution CA1, a wafer laminate was fabricated by heating on a hot plate under the conditions shown in Table 1.

[0167] Afterwards, the following tests were performed on the obtained wafer laminate. The results are listed in Table 1. In addition, the tests were performed by the following method.

[0168] (1) Wafer bending test

[0169] In the fabrication of the above wafer laminate, the warping state of the wafer during the curing of the pre-adhesive layer was confirmed by visual observation. Cases where there was no warping at all were evaluated as “○”, and cases where warping occurred were evaluated as “×”.

[0170] (2) Adhesion test

[0171] The above wafer stack was heated in an oven at 180°C for 1 hour and cooled to room temperature, and the adhesion condition of the wafer interface was visually checked. If no abnormalities such as bubbles occurred at the interface, it was evaluated as good and indicated with "○", and if abnormalities occurred, it was evaluated as poor and indicated with "×".

[0172] (3) Backside grinding resistance test

[0173] Using the above wafer stack, backside grinding of the silicon wafer was performed using a diamond grinding wheel with a grinder (DISCOO DAG-810). After grinding until the substrate thickness reached 50㎛, the presence or absence of abnormalities such as cracks or delamination was examined using an optical microscope (100x magnification). Cases where no abnormalities occurred were evaluated as good and indicated by "○", while cases where abnormalities occurred were evaluated as poor and indicated by "×".

[0174] (4) CVD resistance test

[0175] (3) After completing the back-side grinding resistance test, the wafer stack was introduced into a CVD device and a film deposition test of 2 μm SiO2 film was performed, and the presence or absence of external defects was investigated by visual inspection. If no external defects occurred, it was evaluated as good and indicated as “○”, and if external defects such as voids, wafer swelling, or wafer breakage occurred, it was evaluated as poor and indicated as “×”. The conditions for the CVD resistance test are as follows.

[0176] Device Name: Samco Co., Ltd. Plasma CVD, PD270STL

[0177] RF 500W, withstand voltage 40Pa

[0178] TEOS (Tetraethyl Orthosilicate): O2 = 20sccm:680sccm

[0179] (5) Peel-off test

[0180] First, regarding the peelability of the substrate, (4) a dicing tape (ELP UB-3083D manufactured by Nitto Denko Co., Ltd.) was attached to the wafer side of the wafer stack that had completed the CVD resistance test using a dicing frame, and the dicing tape surface was set on a suction plate by vacuum suction. Then, at room temperature, the glass substrate was peeled off by lifting one point of the glass with tweezers. When the 50㎛ thick wafer could be peeled off without breaking, it was indicated as “○”, and when abnormalities such as cracks occurred, it was evaluated as a defect and indicated as “×”.

[0181] (6) Cleaning and Removal Test

[0182] (5) After the peelability test was completed, a 200mm diameter wafer (exposed to CVD resistance test conditions) mounted on a dicing frame through a dicing tape was set in a spin coater with the peel side facing upward. SPIS-TA-CLEANER 25 (manufactured by Shin-Etsu Kagaku Kogyo Co., Ltd.) was sprayed as a cleaning solvent for 5 minutes, and then isopropyl alcohol (IPA) was sprayed while the wafer was rotated to rinse. Afterward, the appearance was observed to visually check for the presence of any remaining adhesive. If no residue of resin was found, it was evaluated as good and marked with "○", and if residue of resin was found, it was evaluated as poor and marked with "×".

[0183] (7) Peel peel strength test

[0184] Silicon resin solutions A1 to A7 and CA1 to CA5 were each spin-coated onto a silicon wafer (thickness: 725 μm) with a diameter of 200 mm, and a silicon resin layer was formed with the film thickness shown in Table 1 by heating on a hot plate at 100°C for 2 minutes. Subsequently, the curable silicon resin composition layer was irradiated with light using a surface irradiation type UV-LED (wavelength 365 nm) irradiator under the conditions shown in Table 1 to cure the temporary adhesive layer. In addition, for the sample using thermosetting silicon resin solution CA1, the temporary adhesive layer was cured by heating on a hot plate under the conditions shown in Table 1.

[0185] After that, five polyimide tapes measuring 150 mm in length × 25 mm in width were attached to the silicon resin layer on the wafer, and the temporary adhesive layer in the area where the tape was not attached was removed. Using Shimadzu Seisakusho’s AUTOGRAPH (AG-1), 120 mm was peeled off from one end of the tape with a 180° peel at a speed of 300 mm / min at 25°, and the average of the force applied at that time (120 mm stroke × 5 times) was set as the peeling force of the silicon resin layer.

[0186] (8) Measurement of storage modulus

[0187] Curable silicone resin solutions A1 to A7 and CA1 to CA5 were each spin-coated onto a silicon substrate, and a silicone resin layer was formed on the silicon substrate with the film thickness shown in Table 1 by heating on a hot plate at 100°C for 2 minutes. Subsequently, the curable silicone resin composition layer was irradiated with light using a surface irradiation type UV-LED (wavelength 365 nm) irradiator under the conditions shown in Table 1 to cure the temporary adhesive layer. Meanwhile, in the sample using thermosetting silicone resin solution CA1, the temporary adhesive layer was cured by heating on a hot plate under the conditions shown in Table 1.

[0188] A silicon substrate including the obtained adhesive layer was placed between 25mm aluminum plates with a load of 50gf applied to the adhesive layer using TA Instruments' AresG2, and the elastic modulus was measured at 25°C and 1Hz, and the value of the obtained elastic modulus was taken as the storage modulus of the silicon resin layer.

[0189]

[0190]

[0191] As shown in Table 1, the wafer laminates of Examples 1 to 7 containing the adhesive layer of the present invention can be cured at a relatively low temperature and in a short time, and accordingly, wafer warping during curing was reduced. It was also confirmed that they possess sufficient processing durability, excellent peelability, and good cleaning ability after peeling. On the other hand, as shown in Table 2, in Comparative Examples 1 and 2 using a thermally active catalyst, insufficient curing due to insufficient heating or wafer warping during curing was observed. Furthermore, in Comparative Examples 3 and 4 which do not contain non-functional organopolysiloxane, and Comparative Examples 5 and 6 which contain functional organopolysiloxane, the circuit wafer and the support were in tight contact, and as a result, wafer cracking occurred during the peeling process, and peeling was not possible.

[0192] [Example 8]

[0193] Light irradiation was performed on the photocurable silicon resin solution A1 using a surface-irradiation type UV-LED (wavelength 365 nm) irradiator under the conditions shown in Table 2. Subsequently, the solution was spin-coated onto a 200 mm diameter silicon wafer (circuit-forming Si wafer, thickness: 725 μm) having copper posts with a height of 10 μm and a diameter of 40 μm formed across its entire surface. The solution was then heated on a hot plate at 100°C for 2 minutes to deposit a pre-adhesive layer on the wafer bump-forming surface with the film thickness shown in Table 2 below. Using a 200 mm diameter silicon wafer (Si wafer, thickness: 770 μm) as a support, the circuit-forming Si wafer having the pre-adhesive layer and the Si wafer on the support were each bonded using EVG’s wafer bonding device EVG520IS at 25°C for 10 minutes so that the pre-adhesive layer and the Si wafer could be bonded together. -3 A wafer stack was fabricated by performing vacuum bonding with a load of 5 kN and a pressure of less than mbar.

[0194] [Example 9]

[0195] In the above Example 8, a wafer stack was fabricated in the same manner, except that the target for applying the photocurable silicon resin solution A1, which was subjected to light irradiation, was changed from the circuit-forming Si wafer to the Si wafer of the support.

[0196] [Example 10]

[0197] In the above Example 8, a wafer stack was fabricated in the same manner, except that the target for applying the photocurable silicon resin solution A1, which was subjected to light irradiation, was changed from the circuit-forming Si wafer to both the circuit-forming Si wafer and the Si wafer of the support.

[0198] [Example 11]

[0199] In the above Example 8, a wafer stack was fabricated in the same manner except that the photocurable silicone resin solution used was changed from A1 to A6.

[0200] [Example 12]

[0201] In the above Example 9, a wafer stack was fabricated in the same manner except that the photocurable silicone resin solution used was changed from A1 to A6.

[0202] [Example 13]

[0203] In the above Example 10, a wafer stack was fabricated in the same manner except that the photocurable silicone resin solution used was changed from A1 to A6.

[0204] In the above Examples 8 to 13, the same tests as the (1) wafer bending test to (6) cleaning removal test were performed on the obtained wafer laminates. The results are shown in Table 3.

[0205] In addition, for (7) the peel strength test and (8) the storage modulus measurement, a photocurable silicon resin solution that had been previously irradiated with light was spin-coated onto a silicon wafer (Si wafer, thickness: 770 μm) with a diameter of 200 mm, and the silicon resin layer was cured by heating it on a hot plate at 100°C for 5 minutes to prepare a test sample. After that, the peel strength test and the storage modulus measurement test were performed as described above, and the results are listed in Table 3.

[0206]

[0207] As shown in Table 3, in the method for manufacturing a thin wafer according to the present invention, it was confirmed that wafer processability equivalent to that obtained when light irradiation is performed after application and bonding is obtained even when a silicon resin solution that has been light-irradiated in advance is applied and bonded. In this case, since light irradiation that transmits light through the support is unnecessary, advantages such as a wider range of application for the support and the avoidance of light damage to the device wafer can be considered.

Claims

Claim 1 A pre-adhesive for wafer processing for pre-adhering a wafer to a support comprises a photocurable silicone resin composition containing a non-functional organopolysiloxane, wherein the photocurable silicone resin composition containing the non-functional organopolysiloxane comprises: (A) an organopolysiloxane having two or more alkenyl groups per molecule: 100 parts by mass; (B) an organohydrogenpolysiloxane containing hydrogen atoms (SiH groups) bonded to two or more silicon atoms per molecule: an amount such that the molar ratio of the total number of SiH groups in component (B) to the total number of alkenyl groups in component (A) is 0.3 to 10; (C) a non-functional organopolysiloxane: 0.1 to 200 parts by mass; and (D) a photoactive hydrosilylation reaction catalyst: 0.1 to 5,000 ppm in terms of metal atomic weight with respect to the total mass of components (A), (B), and (C). A temporary adhesive for wafer processing that includes Claim 2 A pre-adhesive for wafer processing according to claim 1, wherein a 30 mass% toluene solution of a non-functional organopolysiloxane of component (C) has a viscosity of 100 to 500,000 mPa·s at 25°C. Claim 3 A pre-adhesive for wafer processing according to claim 1, wherein the photocurable silicone resin composition containing the above-mentioned non-functional organopolysiloxane also contains 0.001 to 10 parts by mass of a hydrosilylation reaction control agent as component (E) with respect to the total mass of components (A), (B), and (C). Claim 4 A pre-adhesive for wafer processing according to claim 1, wherein after curing of the photocurable silicone resin composition containing the non-functional organopolysiloxane, the 180° peel strength of a 25 mm wide test specimen on a silicon substrate at 25°C is 2 gf or more and 50 gf or less. Claim 5 A pre-adhesive for wafer processing according to claim 1, wherein after curing of the photocurable silicone resin composition containing the non-functional organopolysiloxane, the storage modulus at 25°C is 1,000 Pa or more and 1,000 MPa or less. Claim 6 A method for manufacturing a thin wafer using a photocurable silicone resin composition comprising a non-functional organopolysiloxane as described in any one of claims 1 to 5, wherein, in a process of bonding and curing a wafer and a support through a pre-adhesive layer (hereinafter, process of (a) and (b)), any one of the following embodiments is included. Herein, in any embodiment, processes (c) to (e) are considered common. (Sunset 1) (a1) A process of applying and bonding a pre-adhesive composition for wafer processing according to any one of claims 1 to 5 to the circuit-forming surface of a wafer having a circuit-forming surface on the surface and a non-circuit-forming surface on the back surface, and / or to the bonding surface of a support with the wafer; (b1) A process of photocuring the pre-adhesive of the bonded wafer; (Sunset 2) (a2) A process of irradiating light onto the pre-adhesive composition for wafer processing according to any one of claims 1 to 5; (b2) A process of applying and bonding the pre-adhesive composition for wafer processing that has been irradiated light in (a2) to the circuit-forming surface of a wafer having a circuit-forming surface on the surface and a non-circuit-forming surface on the back surface, and / or to the bonding surface of a support with the wafer; (c) A process of grinding or polishing the non-circuit-forming surface of a wafer of a wafer stack; (d) A process of performing processing on the non-circuit-forming surface of the wafer; (e) A process of peeling the wafer that has undergone processing from the support. Claim 7 A wafer laminate comprising a support, a pre-adhesive layer obtained from a wafer processing pre-adhesive described in any one of claims 1 to 5 stacked thereon, and a wafer having a circuit forming surface on the front and a circuit non-forming surface on the back, wherein the pre-adhesive layer is peelably adhered to the surface of the wafer. Claim 8 delete

Images