Classifications

• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
  • C09J183/00—Adhesives based on macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing silicon, with or without sulfur, nitrogen, oxygen, or carbon only; Adhesives based on derivatives of such polymers
  • C09J183/04—Polysiloxanes
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
  • C09J5/00—Adhesive processes in general; Adhesive processes not provided for elsewhere, e.g. relating to primers
  • C09J5/06—Adhesive processes in general; Adhesive processes not provided for elsewhere, e.g. relating to primers involving heating of the applied adhesive
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K5/00—Use of organic ingredients
  • C08K5/04—Oxygen-containing compounds
  • C08K5/05—Alcohols; Metal alcoholates
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
  • C09J11/00—Features of adhesives not provided for in group C09J9/00, e.g. additives
  • C09J11/02—Non-macromolecular additives
  • C09J11/06—Non-macromolecular additives organic
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
  • C09J7/00—Adhesives in the form of films or foils
  • C09J7/30—Adhesives in the form of films or foils characterised by the adhesive composition
  • C09J7/35—Heat-activated
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10P—GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
  • H10P72/00—Handling or holding of wafers, substrates or devices during manufacture or treatment thereof
  • H10P72/70—Handling or holding of wafers, substrates or devices during manufacture or treatment thereof for supporting or gripping
  • H10P72/74—Handling or holding of wafers, substrates or devices during manufacture or treatment thereof for supporting or gripping using temporarily an auxiliary support
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K5/00—Use of organic ingredients
  • C08K5/0008—Organic ingredients according to more than one of the "one dot" groups of C08K5/01 - C08K5/59
  • C08K5/005—Stabilisers against oxidation, heat, light, ozone
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K5/00—Use of organic ingredients
  • C08K5/04—Oxygen-containing compounds
  • C08K5/13—Phenols; Phenolates
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K5/00—Use of organic ingredients
  • C08K5/04—Oxygen-containing compounds
  • C08K5/13—Phenols; Phenolates
  • C08K5/134—Phenols containing ester groups
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
  • C09J2203/00—Applications of adhesives in processes or use of adhesives in the form of films or foils
  • C09J2203/326—Applications of adhesives in processes or use of adhesives in the form of films or foils for bonding electronic components such as wafers, chips or semiconductors
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
  • C09J2301/00—Additional features of adhesives in the form of films or foils
  • C09J2301/50—Additional features of adhesives in the form of films or foils characterized by process specific features
  • C09J2301/502—Additional features of adhesives in the form of films or foils characterized by process specific features process for debonding adherents
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
  • C09J2483/00—Presence of polysiloxane
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10P—GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
  • H10P72/00—Handling or holding of wafers, substrates or devices during manufacture or treatment thereof
  • H10P72/70—Handling or holding of wafers, substrates or devices during manufacture or treatment thereof for supporting or gripping
  • H10P72/74—Handling or holding of wafers, substrates or devices during manufacture or treatment thereof for supporting or gripping using temporarily an auxiliary support
  • H10P72/7416—Handling or holding of wafers, substrates or devices during manufacture or treatment thereof for supporting or gripping using temporarily an auxiliary support used during dicing or grinding
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10P—GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
  • H10P72/00—Handling or holding of wafers, substrates or devices during manufacture or treatment thereof
  • H10P72/70—Handling or holding of wafers, substrates or devices during manufacture or treatment thereof for supporting or gripping
  • H10P72/74—Handling or holding of wafers, substrates or devices during manufacture or treatment thereof for supporting or gripping using temporarily an auxiliary support
  • H10P72/7422—Handling or holding of wafers, substrates or devices during manufacture or treatment thereof for supporting or gripping using temporarily an auxiliary support used to protect an active side of a device or wafer
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10P—GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
  • H10P72/00—Handling or holding of wafers, substrates or devices during manufacture or treatment thereof
  • H10P72/70—Handling or holding of wafers, substrates or devices during manufacture or treatment thereof for supporting or gripping
  • H10P72/74—Handling or holding of wafers, substrates or devices during manufacture or treatment thereof for supporting or gripping using temporarily an auxiliary support
  • H10P72/744—Details of chemical or physical process used for separating the auxiliary support from a device or a wafer
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10P—GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
  • H10P72/00—Handling or holding of wafers, substrates or devices during manufacture or treatment thereof
  • H10P72/70—Handling or holding of wafers, substrates or devices during manufacture or treatment thereof for supporting or gripping
  • H10P72/74—Handling or holding of wafers, substrates or devices during manufacture or treatment thereof for supporting or gripping using temporarily an auxiliary support
  • H10P72/744—Details of chemical or physical process used for separating the auxiliary support from a device or a wafer
  • H10P72/7442—Separation by peeling

Definitions

• the present invention relates to a temporary adhesive for wafer processing, a wafer laminate, and a method for manufacturing a thin wafer.
• Three-dimensional semiconductor packaging is becoming essential to achieve even higher density and capacity.
• Three-dimensional packaging technology is a semiconductor manufacturing technology that thins a single semiconductor chip and then stacks it in multiple layers while connecting it with through silicon vias (TSVs).
• TSVs through silicon vias
• a process is required to thin the substrate on which the semiconductor circuit is formed by grinding the non-circuit-forming surface (also called the "back surface") and to form electrodes including TSVs on the back surface.
• a back surface protective tape is applied to the side opposite to the grinding surface to prevent wafer damage during grinding.
• this tape uses an organic resin film as a support base material, and while it is flexible, it is insufficient in strength and heat resistance, making it unsuitable for the TSV formation process or the wiring layer formation process on the back surface.
• a system has been proposed that can adequately withstand the processes of back grinding and TSV and back electrode formation by bonding a semiconductor substrate to a support such as silicon or glass via an adhesive layer.
• the adhesive layer used when bonding the substrate to the support. This needs to be able to bond the substrate to the support without any gaps, be durable enough to withstand subsequent processes, and also enable the thin wafer to be easily peeled off from the support in the end. As this is the last step to be peeled off, in this specification this adhesive layer is also referred to as a temporary adhesive layer.
• Previously known temporary adhesive layers and methods for peeling them off include a technique in which high-intensity light is irradiated onto an adhesive containing a light-absorbing substance to decompose the adhesive layer and peel it off from the support (Patent Document 1), and a technique in which a heat-fusible hydrocarbon compound is used as the adhesive and bonding and peeling are performed in a heated and molten state (Patent Document 2).
• the former technique requires expensive equipment such as a laser, and has problems such as a long processing time per substrate.
• the latter technique is simple because it is controlled only by heating, but has a narrow range of application due to insufficient thermal stability at high temperatures exceeding 200°C.
• these temporary adhesive layers are not suitable for forming a uniform film thickness on a substrate with high step differences, and for complete adhesion to the support.
• Patent Documents 4 and 5 a technology has been publicly known in which a curable silicone composition containing a non-functional polyorganosiloxane is used in the temporary adhesive layer.
• the substrate and support are joined via a temporary adhesive layer, thereby obtaining adhesion between the substrate and the temporary adhesive layer that can withstand processing of the substrate.
• the temporary adhesive layer can be selectively peeled off while still adhering to the support, so that almost no temporary adhesive layer remains on the substrate after peeling. This makes it possible to significantly improve the cleaning removability of the substrate after peeling, making it possible to satisfy both the above-mentioned issues of peelability and cleaning removability.
• the silicone in the temporary adhesive layer is oxidized and deteriorated by the oxygen in the air, causing problems with the substrate and temporary adhesive layer bonding together, particularly near the outer periphery of the bonded substrate. This can lead to problems such as parts of the temporary adhesive layer remaining on the substrate after peeling (resulting in glue residue) or, in the case of a thinned substrate, cracking when peeled off, so an immediate solution was required.
• the present invention has been made in consideration of the above problems, and aims to provide a temporary adhesive for wafer processing, a wafer laminate, and a method for manufacturing thin wafers using the same, which have sufficient substrate retention after bonding even when using substrates with high step differences, are highly compatible with the wafer back grinding process, TSV formation process, and wafer back wiring process, are easy to peel in the peeling process even after a long, high-temperature thermal process in air after bonding, and have excellent residue cleanability after peeling, leading to improved productivity of thin wafers.
• the present invention provides a temporary adhesive for wafer processing for temporarily bonding a wafer to a support, the temporary adhesive for wafer processing being made of a curable silicone resin composition that can be cured by a hydrosilylation reaction, and the curable silicone resin composition containing a phenolic antioxidant that does not contain phosphorus atoms or sulfur atoms.
• the temporary adhesive for wafer processing of the present invention has sufficient substrate retention after bonding, even when a substrate with a high step is used, and is highly compatible with the wafer back grinding process, TSV formation process, and wafer back wiring process. Furthermore, such a temporary adhesive for wafer processing is easy to peel off in the peeling process even after a long, high-temperature thermal process in air after bonding, and also has excellent residue cleanability on the substrate after peeling, leading to improved productivity of thin wafers.
• the curable silicone resin composition is (A) organopolysiloxane having two or more alkenyl groups per molecule: 100 parts by mass, (B) an organohydrogenpolysiloxane containing two or more hydrogen atoms bonded to silicon atoms (SiH groups) per molecule: an amount such that the sum of the SiH groups in component (B) relative to the sum of the alkenyl groups in component (A) is a molar ratio of 0.3 to 10; (C) non-functional organopolysiloxane: 0.1 to 200 parts by mass, (D) a hydrosilylation reaction catalyst: 0.1 to 5,000 ppm in terms of metal atom weight based on the total weight of components (A), (B), and (C); and (E) The phenol-based antioxidant: 1 to 100,000 ppm based on the total mass of the components (A), (B) and (C). It is preferable that the composition contains the following:
• the curable silicone resin composition can contain these components.
• the amount of component (B) is such that the molar ratio of the total SiH groups in component (B) to the total alkenyl groups in component (A) is 0.3 to 5.0.
• the curable silicone resin composition is curable by light and/or heat.
• the curable silicone resin composition curable by light and/or heat, it can be cured more simply and effectively.
• the phenol-based antioxidant of component (E) is a hindered phenol-based antioxidant.
• Such hindered phenol-based antioxidants are preferred because they are more likely to provide antioxidant effects.
• the non-functional organopolysiloxane of component (C) is dimethylpolysiloxane, and that a 30% by weight solution of component (C) in toluene has a viscosity of 100 to 500,000 mPa ⁇ s at 25°C.
• This viscosity range is preferable because it has an appropriate molecular weight, so it does not volatilize when the silicone resin composition is heated and cured, making it difficult to obtain the desired effect, and it does not cause wafer cracks during wafer thermal processes such as CVD, and it also has good workability and coatability.
• the curable silicone resin composition containing the phenolic antioxidant further contains a hydrosilylation reaction inhibitor as component (F) in an amount of 0.001 to 10 parts by mass relative to the total mass of components (A), (B), and (C).
• the composition can be used for a long time, has long-term storage stability, and exhibits good curing properties and workability.
• the 180° peel strength of a 25 mm wide test piece against a silicon substrate at 25°C is 2 gf or more and 100 gf or less.
• the curable silicone resin composition containing the phenolic antioxidant preferably has a storage modulus at 25°C of 1,000 Pa or more and 1,000 MPa or less.
• the curable silicone resin composition has such a storage modulus after curing, there is no risk of the wafer becoming misaligned during wafer grinding, and the composition is also stable during the thermal process on the wafer.
• the curable silicone resin composition containing the phenolic antioxidant to the support to produce a laminate, it is possible to control the peeling interface when peeling off the laminate so that it becomes the interface between the temporary adhesive layer obtained from the temporary adhesive for wafer processing and the support.
• the present invention also relates to a method for manufacturing a wafer laminate, comprising the steps of: (a) peelably adhering a circuit-forming surface of a wafer having a circuit-forming surface on a front side and a circuit-free surface on a rear side to a support using any one of the above-mentioned temporary adhesives for wafer processing to form a wafer laminate; (b) curing the temporary adhesive; (c) grinding or polishing the non-circuit-forming surfaces of the wafers in the wafer stack; (d) processing the non-circuit-forming surface of the wafer; (e) peeling the processed wafer from the support.
• the present invention also provides a wafer laminate comprising a support, a temporary adhesive layer obtained from any one of the above-mentioned temporary adhesives for wafer processing laminated on the support, and a wafer having a circuit-forming surface on its front side and a circuit-free surface on its back side, the temporary adhesive layer being releasably adhered to the front side of the wafer.
• Such a wafer laminate provides stable peelability between the substrate and support, and allows the substrate to be easily peeled off from the support, especially when exposed to high temperatures of 200°C or more for long periods of time after bonding.
• This makes it applicable to a wide range of semiconductor film formation processes, has excellent CVD (chemical vapor deposition) resistance, and allows a temporary adhesive layer with high film thickness uniformity to be formed even on wafers with steps, making it easy to manufacture thin wafers that are prone to cracking.
• CVD chemical vapor deposition
• the temporary adhesive for wafer processing of the present invention can improve the heat resistance of the resin by using a curable silicone resin composition containing an antioxidant. This stabilizes the peelability of the substrate and the support, and the substrate can be easily peeled off from the support, especially when exposed to high temperatures of 200°C or higher for a long time after bonding. Therefore, it can be applied to a wide range of semiconductor film formation processes, has excellent CVD (chemical vapor deposition) resistance, and can form a temporary adhesive layer with high film thickness uniformity even on wafers with steps, making it possible to easily manufacture thin wafers that are prone to cracking.
• CVD chemical vapor deposition
• the temporary adhesive of the present invention can be selectively bonded to the support, no residue from the temporary adhesive remains on the substrate after peeling, and it is also excellent in subsequent cleaning removability. 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.
• the temporary adhesive for wafer processing of the present invention is a temporary adhesive for wafer processing for temporarily adhering a wafer to a support
• the temporary adhesive for wafer processing being made of a curable silicone resin composition that can be cured by a hydrosilylation reaction
• the curable silicone resin composition being characterized in that it contains a phenolic antioxidant that does not contain phosphorus atoms or sulfur atoms.
• the temporary adhesive for wafer processing of the present invention is made of a curable silicone resin composition containing an antioxidant as described above.
• a silicone resin composition having good spin-coatability is preferably used as the temporary adhesive for wafer processing.
• Such a curable silicone resin composition preferably contains, for example, the following components (A) to (E), where the use of a hydrosilylation reaction catalyst, component (D), makes it possible to form a composition that can be cured by heat and/or light.
• the component (A) is an organopolysiloxane having two or more alkenyl groups in one molecule.
• the component (A) may be a linear or branched diorganopolysiloxane having two or more alkenyl groups in one molecule, or a three-dimensional network structure organopolysiloxane having two or more alkenyl groups in one molecule and having siloxane units (Q units) represented by SiO 4/2 units.
• diorganopolysiloxanes or three-dimensional network structure organopolysiloxanes having an alkenyl group content of 0.6 to 9 mol% are preferred.
• the alkenyl group content refers to the proportion of siloxane units containing alkenyl groups in all siloxane units.
• organopolysiloxanes examples include those represented by the following formulas (A-1), (A-2) and (A-3). These may be used alone or in combination of two or more.
• R 1 to R 16 are each independently a monovalent hydrocarbon group other than an aliphatic unsaturated hydrocarbon group, and X 1 to X 5 are each independently an alkenyl-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, with the proviso that a+b+c 1 ⁇ 2. It is preferable that a, b, c 1 , c 2 , d 1 and d 2 are a combination of numbers such that the alkenyl group content is 0.6 to 9 mol%.
• 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 is 0.3 to 3.0 and f 3 /(f 1 +f 2 +f 3 ) is 0.01 to 0.6.
• the monovalent hydrocarbon group other than the aliphatic unsaturated hydrocarbon group preferably has 1 to 10 carbon atoms, and examples thereof include alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, n-pentyl, and n-hexyl; cycloalkyl groups such as cyclopentyl and cyclohexyl; and aryl groups such as phenyl and tolyl. Of these, alkyl groups such as methyl or phenyl are preferred.
• the alkenyl-containing monovalent organic group preferably has 2 to 10 carbon atoms, and examples thereof include alkenyl groups such as vinyl, allyl, hexenyl, and octenyl; (meth)acryloylalkyl groups such as acryloylpropyl, acryloylmethyl, and methacryloylpropyl; (meth)acryloxyalkyl groups such as acryloxypropyl, acryloxymethyl, methacryloxypropyl, and methacryloxymethyl; and alkenyl-containing monovalent hydrocarbon groups such as cyclohexenylethyl and vinyloxypropyl.
• the vinyl group is preferred from an industrial viewpoint.
• a and b are each independently an integer of 0 to 3. It is preferable that a is 1 to 3, since the molecular chain ends are blocked with alkenyl groups, and the highly reactive molecular chain end alkenyl groups allow the reaction to be completed in a short time. From the standpoint of cost, it is industrially preferable that a is 1.
• the properties of the alkenyl-containing diorganopolysiloxane represented by formula (A-1) or (A-2) are preferably oil-like or raw rubber-like.
• the organopolysiloxane represented by formula (A-3) contains SiO 4/2 units and has a three-dimensional network structure.
• e is independently an integer of 1 to 3, and is industrially preferably 1 in terms of cost.
• the product of the average value of e and f 3 /(f 1 +f 2 +f 3 ) is preferably 0.02 to 1.5, and more preferably 0.03 to 1.0.
• the organopolysiloxane represented by formula (A-3) may be used as a solution dissolved in an organic solvent.
• the number average molecular weight (Mn) of the organopolysiloxane of component (A) is preferably 100 to 1,000,000, and more preferably 1,000 to 100,000. Mn in the above range is preferable in terms of workability associated with the viscosity of the composition and processability associated with the storage modulus after curing.
• Mn is a polystyrene-equivalent value measured by gel permeation chromatography using toluene as a solvent.
• the (A) component may be used alone or in combination of two or more.
• the amount of the 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).
• the (B) component is a crosslinking agent, and is an organohydrogenpolysiloxane having at least two, preferably three or more, hydrogen atoms bonded to silicon atoms (SiH groups) in one molecule.
• the organohydrogenpolysiloxane may be linear, branched, or cyclic.
• the organohydrogenpolysiloxane may be used alone or in combination of two or more.
• 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 the present invention, the viscosity is the value measured at 25°C using a rotational viscometer.
• the Mn of the organohydrogenpolysiloxane of component (B) is preferably 100 to 100,000, and more preferably 500 to 10,000. Mn in the above range is preferable in terms of workability associated with the viscosity of the composition and processability associated with the storage modulus after curing.
• the (B) component is preferably blended so that the molar ratio (SiH groups/alkenyl groups) of the sum of the SiH groups in the (B) component to the sum of the alkenyl groups in the (A) component is in the range of 0.3 to 10, more preferably in the range of 0.3 to 5.0, and even more preferably in the range of 0.5 to 3.0. If the molar ratio is 0.3 or more, the crosslink density does not decrease and the temporary adhesive layer is sufficiently cured. Also, if the molar ratio is 10 or less, the crosslink density does not become too high, sufficient adhesion and tack are obtained, and the usable time of the treatment liquid can be extended.
• Component (C) is a non-functional organopolysiloxane.
• “non-functional” means that the molecule does not have any reactive groups such as hydrogen atoms, halogen atoms, hydroxyl groups, or alkoxy groups directly bonded to silicon atoms, and does not have any reactive groups such as alkenyl groups or epoxy groups bonded to silicon atoms directly or via any group.
• Such non-functional organopolysiloxanes include, for example, 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, ethyl, propyl, butyl, pentyl, hexyl, and heptyl; cycloalkyl groups such as cyclohexyl; aryl groups such as phenyl, tolyl, xylyl, and naphthyl; and aralkyl groups such as benzyl and phenethyl.
• some or all of the hydrogen atoms in these groups may be substituted with halogen atoms such as chlorine, fluorine, and bromine atoms.
• the monovalent hydrocarbon group is preferably an alkyl group or an aryl group, and more preferably a methyl group or a phenyl group.
• the molecular structure of the non-functional organopolysiloxane of component (C) is not particularly limited and may be linear, branched, cyclic, etc., but linear or branched organopolysiloxanes are preferred, and linear diorganopolysiloxanes in which the main chain is basically composed of repeating diorganosiloxane units and both ends of the molecular chain are blocked with triorganosiloxy groups are preferred.
• the (C) component, the non-functional organopolysiloxane preferably has a viscosity (25°C) in a 30% by weight toluene solution of 100 to 500,000 mPa ⁇ s, more preferably 200 to 100,000 mPa ⁇ s, from the viewpoints of workability of the composition, applicability to substrates, mechanical properties of the cured product, and peelability of the support. If it is in this range, it has an appropriate molecular weight, so it does not volatilize when the silicone resin composition is heated and cured, making it difficult to obtain the desired effect, does not cause wafer cracks in wafer thermal processes such as CVD, and is preferable because it has good workability and applicability.
• the non-functional organopolysiloxane may be a dimethylsiloxane polymer capped with trimethylsiloxy groups at both molecular chain ends, a phenylmethylpolysiloxane capped with trimethylsiloxy groups at both molecular chain ends, a 3,3,3-trifluoropropylmethylsiloxane polymer capped with trimethylsiloxy groups at both molecular chain ends, a dimethylsiloxane-methylphenylsiloxane copolymer capped with trimethylsiloxy groups at both molecular chain ends, a dimethylsiloxane-3,3,3-trifluoropropylmethyl copolymer capped with trimethylsiloxy groups at both molecular chain ends, Examples of such copolymers include methylphenylsiloxane/3,3,3-trifluoropropylmethyl copolymers capped with trimethylsiloxy groups at both molecular chain ends, dimethylsiloxane
• the non-functional organopolysiloxane of component (C) may be used alone or in combination of two or more. It is preferable that the properties of the non-functional organopolysiloxane are oil-like or rubber-like.
• the amount of component (C) is preferably 0.1 to 200 parts by mass, and more preferably 1 to 100 parts by mass, per 100 parts by mass of component (A). If this ratio is 0.1 parts by mass or more, this is preferable because it allows for easy peeling, particularly in the process of peeling the support from the substrate. Furthermore, if this ratio is 200 parts by mass or less, this is preferable because it allows for durability in wafer processing without the wafer peeling during wafer processing such as wafer back grinding and subsequent heat treatment.
• Component (D) is a hydrosilylation catalyst, preferably a platinum group metal-based hydrosilylation 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), and includes thermally activated hydrosilylation catalysts (D-1) that are activated by heat, and photoactivated hydrosilylation catalysts (D-2) that are activated by light.
• These hydrosilylation catalysts are generally compounds of noble metals and are expensive, so platinum or platinum compounds, which are relatively easy to obtain, are often used.
• (D-1) Thermally activated hydrosilylation reaction catalyst
• platinum compounds include chloroplatinic acid or complexes of chloroplatinic acid with olefins such as ethylene, complexes of chloroplatinic acid with alcohols or vinylsiloxanes, and metallic platinum supported on silica, alumina, carbon, etc.
• platinum group metal catalysts other than platinum compounds rhodium, ruthenium, iridium, and palladium compounds are also known, and examples thereof include RhCl(PPh 3 ) 3 , RhCl(CO)(PPh 3 ) 2 , Ru 3 (CO) 12 , IrCl(CO)(PPh 3 ) 2 , and Pd(PPh 3 ) 4.
• Ph is a phenyl group.
• This photoactivated hydrosilylation catalyst is a catalyst that is activated by irradiation with light, particularly ultraviolet light with a wavelength of 300 to 400 nm, and promotes the addition reaction between the alkenyl group in component (A) and the Si-H group in component (B).
• This promotion effect is temperature dependent, with a higher promotion effect being obtained at higher temperatures.
• the ligand of this catalyst is preferably one that exhibits catalytic activity under medium to long wavelength UV light, from UV-B to UV-A, in order to reduce damage to the wafer.
• Examples of such ligands include cyclic diene ligands and ⁇ -diketonato ligands.
• photoactivatable hydrosilylation reaction catalysts include, as cyclic diene ligand types, for example, ( ⁇ 5 -cyclopentadienyl)tri( ⁇ -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), (dimethylphenyl
• platinum complex examples include ⁇ -diketonatoplatinum(II) or platinum(IV), particularly specifically, trimethyl(acetylacetonato)platinum(IV), trimethyl(3,5-heptanedionato)platinum(IV), trimethyl(methylacetoacetate)platinum(IV), bis(2,4-pentanedionato)platinum(II), bis(2,4-hexanedionato)platinum(II), bis(2,4-heptanedionato)platinum(II), bis(3,5-heptanedionato)platinum(II), bis(1-phenyl-1,3-butanedionato)platinum(II), bis(1,3-diphenyl-1,3-propanedionato)platinum(II), and bis(hexafluoroacetylacetonato)platinum(II).
• a suitable solvent here means a solvent that is soluble in any or all of the components (A), (B) and (C) and is suitable for the working environment and process.
• the amount of component (D) added is an effective amount, and is usually 0.1 to 5,000 ppm, preferably 1 to 1,000 ppm, calculated as the metal atom weight relative to the total mass of components (A), (B), and (C). If it is 0.1 ppm or more, the curability of the composition will not decrease, and the crosslink density and retention 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.
• Component (E) is a phenol-based antioxidant, and it is preferable that it does not contain phosphorus or sulfur atoms in its chemical structure in order to avoid inhibition of the hydrosilylation reaction. Therefore, in the present invention, it is essential that the curable silicone resin composition contains a phenol-based antioxidant that does not contain phosphorus or sulfur atoms.
• antioxidants include, for example, 4,4'-dihydroxy-3,3',5,5'-tetraisopropylbiphenyl, 3-(3,5-di-tert-butyl-4-hydroxyphenyl)-N'-[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propanoyl]propanehydrazide, 4,6-di-tert-butylbenzene-1,3-diol, bis[3-[3-(tert-butyl)-4-hydroxy-5-methylphenyl]propanoic acid]2,4,8,10-tetraoxaspiro[5.5]undecane-3,9-diylbis(2-methylpropane-2,1-diyl), 2,2'-methylenebis[6-( 1-methylcyclohexyl)-p-cresol], 3-(3,5-di-tert-butyl-4-hydroxyphenyl)octa
• antioxidants When using these antioxidants, if they are solid they can be used in solid form, but in order to obtain a more uniform cured product, it is preferable to use them after dissolving them in a suitable solvent.
• the amount of component (E) added is an effective amount, and is usually 1 to 100,000 ppm, preferably 10 to 10,000 ppm, based on the total mass of components (A), (B), and (C).
• An amount of 1 ppm or more can improve the heat resistance stability of the cured product, and an amount of 100,000 ppm or less can improve the heat resistance stability without affecting the curability or physical properties after curing.
• the curable silicone resin composition may further contain a reaction inhibitor (hydrosilylation reaction inhibitor) as component (F), which is optionally added as necessary to prevent thickening or gelation of the composition when the composition is prepared or applied to a substrate.
• a reaction inhibitor hydrosilylation reaction inhibitor
• the reaction inhibitors include 3-methyl-1-butyn-3-ol, 3-methyl-1-pentyn-3-ol, 3,5-dimethyl-1-hexyn-3-ol, 1-ethynylcyclohexanol, 3-methyl-3-trimethylsiloxy-1-butyne, 3-methyl-3-trimethylsiloxy-1-pentyne, 3,5-dimethyl-3-trimethylsiloxy-1-hexyne, 1-ethynyl-1-trimethylsiloxycyclohexane, bis(2,2-dimethyl-3-butynyloxy)dimethylsilane, 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane, 1,1,3,3-tetramethyl-1,3-divinyldisiloxane, and the like. Of these, 1-ethynylcyclohexanol and 3-methyl-1-butyn-3-ol are preferred.
• the content is preferably 0.001 to 10 parts by mass, and more preferably 0.01 to 10 parts by mass, relative to the total mass of components (A), (B), and (C). If the content of component (F) is within the above range, the usable time of the composition is long, long-term storage stability is obtained, and curability and workability are good.
• the curable silicone resin composition may further contain an organopolysiloxane containing R A 3 SiO 0.5 units (wherein R A are each independently a substituted or unsubstituted monovalent hydrocarbon group having 1 to 10 carbon atoms) and SiO 2 units, in which the molar ratio of R A 3 SiO 0.5 units to SiO 2 units (R A 3 SiO 0.5 /SiO 2 ) is 0.3 to 1.8.
• the amount added is preferably 0 to 500 parts by mass per 100 parts by mass of component (A).
• a filler such as silica may be added to the curable silicone resin composition to further increase the physical strength of the temporary adhesive layer obtained from the composition.
• the curable silicone resin composition may be used in the form of a solution by adding a solvent in order to improve workability and mixability by lowering the viscosity of the composition, and to adjust the film thickness of the temporary adhesive layer.
• a solvent there are no particular limitations on the solvent used as long as it can dissolve the above-mentioned components, but preferred solvents include hydrocarbon solvents such as pentane, hexane, cyclohexane, isooctane, nonane, decane, p-menthane, pinene, isododecane, and limonene.
• the method of making the solution may include a method in which the curable silicone resin composition is prepared, and then a solvent is added to adjust the viscosity to the desired level, or a method in which the highly viscous components (A), (B) and/or (C) are first diluted with a solvent to improve workability and mixability, and then the remaining components are mixed.
• the mixing method used to make the solution may be selected appropriately based on the viscosity of the composition and workability, such as a shaking mixer, a magnetic stirrer, or various mixers.
• the amount of solvent to be added may be set appropriately from the viewpoints of adjusting the viscosity and workability of the composition, the film thickness of the temporary adhesive layer, etc., but is preferably 5 to 900 parts by mass, and more preferably 10 to 400 parts by mass, per 100 parts by mass of the curable silicone resin composition.
• the temporary adhesive layer can be formed by applying the curable silicone resin composition onto a substrate by a method such as spin coating or roll coating.
• a method such as spin coating or roll coating.
• the viscosity of the solution of the curable silicone resin composition at 25°C is preferably 1 to 100,000 mPa ⁇ s, and more preferably 10 to 10,000 mPa ⁇ s.
• the curable silicone resin composition After curing, the curable silicone resin composition has a 180° peel strength at 25°C of a 25 mm wide test piece (e.g., a glass test piece) against a silicon substrate of typically 2 to 100 gf, but preferably 3 to 50 gf, and more preferably 5 to 30 gf. If it is 2 gf or more, there is no risk of the wafer shifting during wafer grinding, and if it is 100 gf or less, the wafer can be easily peeled off.
• a 25 mm wide test piece e.g., a glass test piece
• the curable silicone resin composition has a storage modulus at 25°C after curing of 1,000 Pa to 1,000 MPa, preferably 10,000 Pa to 100 MPa. If the storage modulus is 1,000 Pa or more, the film formed is strong and there is no risk of the wafer shifting or the associated wafer cracking during wafer grinding, and if it is 1,000 MPa or less, deformation stress during wafer thermal processes such as CVD can be alleviated and the film is stable during wafer thermal processes.
• the curable silicone resin composition can selectively control the interface at the time of peeling after forming the laminate by applying the curable silicone resin composition to the wafer (substrate) side or the support side.
• the temporary adhesive layer remains on the support as a residue, making it possible to simplify the subsequent wafer (substrate) cleaning process, which is preferable in terms of improving workability.
• the target to which the curable silicone resin composition is applied is changed to the support and the bonded body with the wafer (substrate) is peeled off, selective peeling is possible at the temporary adhesive layer/support interface.
• the residue of the temporary adhesive layer remains on the wafer (substrate), which may lead to a decrease in workability in the subsequent wafer (substrate) cleaning process.
• the method for producing a thin wafer of the present invention is characterized in that the above-mentioned temporary adhesive for wafer processing is used for temporarily bonding a wafer having a semiconductor circuit or the like to a support.
• Step (a) is a temporary bonding step in which the circuit-forming surface of a wafer having a circuit-forming surface on its front side and a non-circuit-forming surface on its back side is releasably bonded to a support using the temporary adhesive for wafer processing to form a wafer laminate.
• any one of the following methods is applied: a method of forming a temporary adhesive layer on the surface of the wafer using the temporary adhesive for wafer processing, and bonding the support and the surface of the wafer via the temporary adhesive layer; a method of forming a temporary adhesive layer on the surface of a support using the temporary adhesive for wafer processing, and bonding the support and the surface of the wafer via the temporary adhesive layer; or a method of forming temporary adhesive layers on both the surface of the wafer and the surface of the support using the temporary adhesive for wafer processing, and bonding the support and the surface of the wafer via the temporary adhesive layer.
• Wafer applicable to the present invention is usually a semiconductor wafer.
• the semiconductor wafer include not only silicon wafers, but also germanium wafers, gallium arsenide wafers, gallium phosphide wafers, and gallium arsenide aluminum wafers.
• the thickness of the wafer is not particularly limited, but is typically 600 to 800 ⁇ m, and more typically 625 to 775 ⁇ m.
• the support may be a substrate such as a silicon wafer, a glass plate, or a quartz wafer, but is not limited to these.
• the support when the curable silicone resin composition is cured without irradiating light through the support, the support may not have light transmittance.
• the curable silicone resin composition when the curable silicone resin composition is cured by irradiating light through the support, it is preferable to use a support that has light transmittance.
• the temporary adhesive layer may be formed by laminating a film of the curable silicone resin composition on a wafer or support, or by applying the curable silicone resin composition by a method such as spin coating or roll coating.
• the curable silicone resin composition is a solution containing a solvent, after application, it is prebaked in advance at a temperature of preferably 40 to 200°C, more preferably 50 to 150°C, depending on the volatilization conditions of the solvent, before use.
• the temporary adhesive layer is preferably formed and used with a film thickness of 0.1 to 500 ⁇ m, preferably 1.0 to 200 ⁇ m. If the film thickness is 0.1 ⁇ m or more, when it is applied to a substrate, it can be applied to the entire substrate without leaving any areas uncoated. On the other hand, if the film thickness is 500 ⁇ m or less, it can withstand the grinding process when forming a thin wafer.
• the method for bonding the support and the wafer surface via the temporary adhesive layer includes a method of uniformly pressing the support and wafer together under reduced pressure, preferably in a temperature range of 10 to 200°C, more preferably 20 to 150°C.
• the pressure applied when pressing the wafer with the temporary adhesive layer formed thereon and the support body depends on the viscosity of the temporary adhesive layer, but is preferably 0.01 to 10 MPa, and more preferably 0.1 to 1.0 MPa. If the pressure is 0.01 MPa or more, the circuit formation surface and the space between the wafer and the support body can be filled with the temporary adhesive layer, and if the pressure is 10 MPa or less, there is no risk of the wafer cracking or deterioration of the flatness of the wafer and temporary adhesive layer, and subsequent wafer processing is good.
• Wafer bonding can be performed using a commercially available wafer bonder, such as EVG's EVG520IS, 850TB, or SUSS MicroTec's XBS300.
• a commercially available wafer bonder such as EVG's EVG520IS, 850TB, or SUSS MicroTec's XBS300.
• Step (b) is a step of curing the temporary adhesive layer.
• the temporary adhesive layer is cured by heating at preferably 50 to 300° C., more preferably 100 to 200° C., for preferably 1 minute to 4 hours, more preferably 5 minutes to 2 hours.
• the temporary adhesive layer may be photocured by irradiating light from the light-transmitting support side, or the laminate substrate may be formed with a photocurable silicone resin composition that has been irradiated with light in advance, and then cured.
• the type of active light is not particularly limited, but ultraviolet light is preferred, and ultraviolet light with a wavelength of 300-400 nm is more preferred.
• the ultraviolet ray irradiation amount (illuminance) is preferably 100 mJ/cm 2 to 100,000 mJ/cm 2 as an integrated light amount, preferably 500 mJ/cm 2 to 10,000 mJ/cm 2 , and more preferably 1,000 to 5,000 mJ/cm 2 in order to obtain good curing properties. If the ultraviolet ray irradiation amount (illuminance) is equal to or greater than the lower limit of the above range, sufficient energy can be obtained to activate the photoactivated hydrosilylation reaction catalyst in the temporary adhesive layer, and a sufficient cured product can be obtained.
• the amount of ultraviolet light irradiation is equal to or less than the upper limit of the above range, sufficient energy is irradiated to the composition, and a sufficient cured product can be obtained without causing decomposition of the components in the polymer layer or deactivation of part of the catalyst.
• the ultraviolet radiation may be light having multiple emission spectra, or light having a single emission spectrum.
• the single emission spectrum may be a broad spectrum in the region of 300 nm to 400 nm.
• Light having a single emission spectrum is light having a peak (i.e., maximum peak wavelength) in the range of 300 nm to 400 nm, preferably 350 nm to 380 nm.
• Examples of light sources that irradiate such light include ultraviolet light-emitting diodes (ultraviolet LEDs) and ultraviolet light-emitting semiconductor element light sources such as ultraviolet light-emitting semiconductor lasers.
• Light sources that emit light with multiple emission spectra include lamps such as metal halide lamps, xenon lamps, carbon arc lamps, chemical lamps, sodium lamps, low-pressure mercury lamps, high-pressure mercury lamps, and extra-high-pressure mercury lamps, as well as gas lasers such as nitrogen lasers, liquid lasers using organic dye solutions, and solid-state lasers that contain rare earth ions in inorganic single crystals.
• lamps such as metal halide lamps, xenon lamps, carbon arc lamps, chemical lamps, sodium lamps, low-pressure mercury lamps, high-pressure mercury lamps, and extra-high-pressure mercury lamps, as well as gas lasers such as nitrogen lasers, liquid lasers using organic dye solutions, and solid-state lasers that contain rare earth ions in inorganic single crystals.
• 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 over a wide wavelength region), and when a substrate that is optically transparent to wavelengths shorter than 300 nm, such as a quartz wafer, is used as the support, it is preferable to remove light with wavelengths shorter than 300 nm using an optical filter in order to obtain a sufficient cured product.
• the irradiance of each wavelength in the wavelength region shorter than 300 nm 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%.
• the peak wavelength showing the maximum absorbance among them is the maximum peak wavelength.
• the optical filter there are no particular limitations on the optical filter, and any known filter may be used as long as it cuts wavelengths shorter than 300 nm. For example, a 365 nm bandpass filter or the like can be used.
• the illuminance and spectral distribution of ultraviolet light can be measured using a spectroradiometer, such as the USR-45D (Ushio Electric).
• the light irradiation device is not particularly limited, but examples that can be used include spot-type irradiation devices, surface-type irradiation devices, line-type irradiation devices, and conveyor-type irradiation devices.
• the light exposure time depends on the illuminance and cannot be generally specified, but 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 exposure time will be appropriately short and will not cause any particular problems in the work process.
• the photocurable silicone resin composition that has been irradiated with light will gel after 1 to 120 minutes, and particularly after 5 to 60 minutes.
• gelation refers to a state in which the curing reaction of the photocurable silicone resin composition has partially progressed and the composition has lost its fluidity.
• the curing speed of the photocurable silicone resin composition after irradiation with light depends on the environmental temperature, it is preferable to leave the wafer (laminate substrate) at a temperature of preferably 20 to 150°C, and more preferably 30 to 100°C, from the viewpoint of improving workability.
• Step (c) is a step of grinding or polishing the non-circuit-forming surface of the wafer (i.e., the wafer of the wafer laminate) temporarily bonded 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.
• the method of grinding the back side 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 grindstone (diamond, etc.) by spraying water on them.
• An example of an apparatus for grinding the back side of the wafer is DAG-810 (trade name) manufactured by Disco Corporation.
• the back side of the wafer may be subjected to chemical mechanical polishing (CMP).
• Step (d) is a step of processing the non-circuit-forming surface of the wafer laminate obtained by grinding the non-circuit-forming surface in step (c). That is, it is a step of processing the non-circuit-forming 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, and the like.
• conventionally known processes include metal sputtering for forming electrodes, wet etching for etching the metal sputtering layer, application of a resist to form a mask for metal wiring formation, exposure, and development to form a pattern, resist peeling, dry etching, formation of metal plating, silicon etching for TSV formation, and oxide film formation on the silicon surface.
• Step (e) is a step of peeling off the wafer processed in step (d) from the support, that is, a step of peeling off the wafer from the support before dicing after various processing is performed on the thinned wafer.
• This peeling step is generally performed under relatively mild conditions of room temperature to about 60°C.
• peeling methods include a method in which one of the wafer or the support of the wafer stack is fixed horizontally and the other is lifted at a certain angle from the horizontal direction, a method in which a protective film is attached to the ground surface of the ground wafer, and the wafer and the protective film are peeled off from the wafer stack by a peel method, and the like. When the peeling step is performed by these peeling methods, it is usually performed at room temperature.
• step (e) is (e1) applying a dicing tape to the wafer surface of the processed wafer; It is preferable to include a step (e2) of vacuum-adsorbing the dicing tape surface onto the adsorption surface, and a step (e3) of peeling off the support from the processed wafer with the adsorption surface at a temperature in the range of 10 to 100° C. In this way, the support can be easily peeled off from the processed wafer, and the subsequent dicing step can be easily performed.
• step (f) It is preferable to carry out a step of removing the temporary adhesive layer remaining on the circuit-forming surface of the peeled wafer.
• a part of the temporary adhesive layer may remain on the circuit-forming surface of the wafer peeled from the support in step (e), and the temporary adhesive layer can be removed, for example, by washing the wafer.
• any cleaning liquid that dissolves the silicone resin of the temporary adhesive layer can be used, and specific examples include pentane, hexane, cyclohexane, decane, isononane, p-menthane, pinene, isododecane, limonene, etc. These solvents may be used alone or in combination of two or more.
• a base or an acid may be added to the cleaning solution.
• amines such as ethanolamine, diethanolamine, triethanolamine, triethylamine, ammonia, and ammonium salts such as tetramethylammonium hydroxide can be used.
• acid organic acids such as acetic acid, oxalic acid, benzenesulfonic acid, and dodecylbenzenesulfonic acid can be used.
• the amount of the base or acid added is preferably an amount that results in a concentration in the cleaning solution of 0.01 to 10 mass%, more preferably 0.1 to 5 mass%.
• an existing surfactant may be added to improve the removability of residual matter.
• the SPIS-TA-CLEANER series manufactured by Shin-Etsu Chemical Co., Ltd.
• the wafer can be washed using a paddle with the above-mentioned cleaning solution, spraying the wafer, or immersing the wafer in a cleaning solution tank.
• the temperature during washing is preferably 10 to 80°C, more preferably 15 to 65°C.
• the temporary adhesive layer can be dissolved using the cleaning solution, and the wafer can be rinsed with water or alcohol and then dried.
• the thickness of the thin wafer obtained by the manufacturing method of the present invention is typically 5 to 300 ⁇ m, and more typically 10 to 100 ⁇ m.
• the present invention will be explained in more detail below with reference to preparation examples, comparative preparation examples, working examples, and comparative examples, but the present invention is not limited to these examples.
• the viscosity is measured at 25°C using a rotational viscometer.
• thermosetting silicone resin solution A1 0.4 parts by mass of hydrosilylation reaction catalyst CAT-PL-5 (manufactured by Shin-Etsu Chemical Co., Ltd., platinum concentration 1.0 mass%) was added thereto, and the mixture was filtered with a 0.2 ⁇ m membrane filter to prepare a thermosetting silicone resin solution A1.
• the viscosity of the resin solution A1 at 25 ° C was 2,300 mPa ⁇ s.
• the total number of SiH groups in component (B) relative to the total number of alkenyl groups in component (A) in Preparation Example 1 is calculated according to the following formula.
• Amount of Si-Vi from PDMS (mol) (PDMS addition amount/PDMS molecular weight) ⁇ PDMS molecular weight/ ⁇ [(D unit molecular weight) ⁇ (D unit mol%/100)]+[(D Vi unit molecular weight) ⁇ (D vi unit mol%/100)] ⁇ > ⁇ (D vi unit mol%/100)
• Amount of Si-Vi from PVMS having a resin structure containing Vi groups (moles) PVMS addition amount/PVMS molecular weight) ⁇ PVMS molecular weight/ ⁇ [(Q unit molecular weight) ⁇ (Q unit mol %/100)]+[(M unit molecular weight) ⁇ (M unit mol %/100)]+[(M Vi unit molecular weight) ⁇ (M Vi
• the Si--H/Si--Vi (molar ratio) of Preparation Example 1 obtained from the above (1) to (3) is 1.0.
• thermosetting silicone resin solution A2 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 ⁇ m membrane filter to prepare a thermosetting silicone resin solution A2.
• the viscosity of resin solution A2 at 25° C. was 1,800 mPa ⁇ s.
• the Si—H/Si—Vi (molar ratio) in this Preparation Example 2 was 1.5.
• thermosetting silicone resin solution A3 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 ⁇ m membrane filter to prepare a thermosetting silicone resin solution A3.
• the viscosity of the resin solution A3 at 25 ° C was 2,800 mPa ⁇ s.
• the Si-H/Si-Vi (molar ratio) in this Preparation Example 3 was 0.7.
• thermosetting silicone resin solution A4 was prepared in the same manner as in Preparation Example 3, except that the amount of the antioxidant represented by the formula (M-3) was changed from 0.1 parts by mass to 0.05 parts by mass, and the amount of the organohydrogenpolysiloxane having Mn of 2,400 and consisting of 16.1 mol% (CH 3 )HSiO 2/2 units (D H units) was changed from 15 parts by mass to 21 parts by mass.
• the viscosity of resin solution A4 at 25°C was 2,400 mPa ⁇ s.
• the Si-H/Si-Vi (molar ratio) in Preparation Example 4 was 1.0.
• thermosetting silicone resin solution A5 was prepared in the same manner as in Preparation Example 4, except that the amount of the antioxidant represented by the above formula (M-3) added was changed from 0.1 parts by mass to 0.4 parts by mass.
• the viscosity of resin solution A5 at 25°C was 2,400 mPa ⁇ s.
• the Si-H/Si-Vi (molar ratio) in this Preparation Example 5 was 1.0.
• a photocurable silicone resin solution A6 was prepared in the same manner as in Preparation Example 1, except that a photoactivatable hydrosilylation catalyst; (methylcyclopentadienyl)trimethylplatinum(IV) toluene solution (platinum concentration 1.0 mass%) (0.4 mass parts) was added instead of the hydrosilylation catalyst CAT-PL-5 (0.4 mass parts).
• the viscosity of resin solution A6 at 25°C was 2,300 mPa ⁇ s.
• the Si-H/Si-Vi (molar ratio) in this Preparation Example 6 was 1.0.
• a photocurable silicone resin solution A7 was prepared in the same manner as in Preparation Example 2, except that a photoactivatable hydrosilylation catalyst; (methylcyclopentadienyl)trimethylplatinum(IV) toluene solution (platinum concentration 1.0 mass%) (0.4 mass parts) was added instead of the hydrosilylation catalyst CAT-PL-5 (0.4 mass parts).
• the viscosity of resin solution A7 at 25°C was 1,800 mPa ⁇ s.
• the Si-H/Si-Vi (molar ratio) in this Preparation Example 7 was 1.5.
• thermosetting silicone resin solution CA1 was prepared in the same manner as in Preparation Example 1, except that the solution consisting of 0.1 parts by mass of the antioxidant represented by the above formula (M-1) and 0.4 parts by mass of toluene was not added.
• the viscosity of the resin solution CA1 at 25°C was 2,400 mPa ⁇ s.
• the Si-H/Si-Vi (molar ratio) in this Comparative Preparation Example 1 was 1.0.
• thermosetting silicone resin solution CA2 was prepared in the same manner as in Preparation Example 1, except that 0.1 parts by mass of an antioxidant represented by the following formula (M-4) was added instead of 0.1 parts by mass of the antioxidant represented by the above formula (M-1).
• the viscosity of resin solution CA2 at 25° C. was 2,300 mPa ⁇ s.
• the Si-H/Si-Vi (molar ratio) in this Comparative Preparation Example 2 was 1.0.
• a photocurable silicone resin solution CA3 was prepared in the same manner as in Preparation Example 6, except that 0.1 parts by mass of an antioxidant represented by the following formula (M-5) was added instead of 0.1 parts by mass of the antioxidant represented by the above formula (M-1).
• the viscosity of the resin solution CA3 at 25° C. was 2,300 mPa ⁇ s.
• the Si-H/Si-Vi (molar ratio) in this Comparative Preparation Example 3 was 1.0.
• the silicon wafer and the glass wafer having the temporary adhesive layer were vacuum-bonded at 100° C. for 2 minutes, 10 ⁇ 3 mbar or less, and a load of 5 kN using a wafer bonding device EVG520IS manufactured by EVG Corporation, so that the temporary adhesive layer and the glass wafer were joined together, and then a wafer laminate was produced by carrying out a curing process.
• the curing conditions here were as follows: when a thermosetting silicone resin solution was used, the curing was carried out by heating in an oven at 180°C for 1 hour; when a photocurable silicone resin solution was used, the curing was carried out by irradiating with light for 120 seconds at an illuminance of 100 mW/ cm2 at 23°C using a surface irradiation type UV-LED (wavelength 365 nm) irradiator.
• the curable silicone resin solutions A1 and A6 were applied by spin coating onto a glass wafer support having a diameter of 200 mm (thickness: 500 ⁇ m), and heated in an oven at 100 ° C.
• a silicon wafer (thickness: 725 ⁇ m) having a diameter of 200 mm and a copper post having a height of 10 ⁇ m and a diameter of 40 ⁇ m formed on the entire surface of the surface and a glass wafer having a temporary adhesive layer were vacuum bonded at 100 ° C. for 2 minutes, 10 -3 mbar or less, and a load of 5 kN using a wafer bonding device EVG520IS manufactured by EVG Corporation so that the temporary adhesive layer and the silicon wafer were joined together, and then a wafer laminate was produced by carrying out a curing process.
• the curing conditions here were as follows: when a thermosetting silicone resin solution was used, the curing was carried out by heating in an oven at 180°C for 1 hour; when a photocurable silicone resin solution was used, the curing was carried out by irradiating with light for 120 seconds at an illuminance of 100 mW/ cm2 at 23°C using a surface irradiation type UV-LED (wavelength 365 nm) irradiator.
• peelability test after heat resistance test in air The peelability of the substrate was measured by first attaching a dicing tape (ELP UB-3083D manufactured by Nitto Denko Corporation) to the wafer side of the wafer laminate that had been subjected to the heat resistance test in air (3) above, using a dicing frame, and setting the dicing tape surface on a suction plate by vacuum suction. Thereafter, the glass wafer was peeled off by lifting one point of the glass with tweezers at room temperature. The case where the 30 ⁇ m-thick wafer could be peeled off without cracking was indicated by " ⁇ ", and the case where an abnormality such as cracking occurred was evaluated as defective and indicated by " ⁇ ". In addition, it was also confirmed whether the temporary adhesive layer remained as a residue on the substrate (silicon wafer) side or the support (glass wafer) side.
• a dicing tape ELP UB-3083D manufactured by Nitto Denko Corporation
• the silicone resin layer was then cured under the conditions shown in Table 1, cooled to room temperature, and five polyimide tapes with a length of 150 mm and a width of 25 mm were attached to the silicone resin layer on the wafer, and the temporary adhesive layer was removed from the portion where the tape was not attached.
• AUTOGRAPH AG-1 from Shimadzu Corporation
• the tape was peeled off 120 mm from one end at 180° peeling at 25° C. and a speed of 300 mm/min, and the average of the force applied at that time (120 mm stroke x 5 times) was taken as the initial peeling force of the silicone resin layer.
• a cured silicone resin layer was prepared on the surface of the wafer having bumps in the same manner as above, and the tape peel strength after heat treatment in an oven at 250° C. in air for 1 hour was measured as the post-heat-resistant peel strength.
• the temporary adhesive made of the curable silicone resin composition containing an antioxidant which is an embodiment of the present invention, exhibits sufficient curing properties, and is excellent in wafer processing durability, peeling stability after high-temperature and long-term heating treatment in air, and cleaning removability after peeling.
• the results of thermogravimetric measurements in air also confirmed the improved effect of heat resistance stability.
• Comparative Example 1 which does not contain an antioxidant, no effects were observed when the material was heated at high temperatures for a long period of time in nitrogen, but when the material was heated at high temperatures for a long period of time in air, it was confirmed that there was an adverse effect on the subsequent peelability. Furthermore, in Comparative Examples 2 and 3, which used antioxidants containing sulfur or phosphorus atoms in their structure, the curing was insufficient, resulting in defects in particular in wafer processability.
• Comparative Examples 4 and 5 in which a curable silicone resin composition was applied to a glass carrier support to produce a bonded body with a silicon wafer substrate, there was no difference from the Examples up to the peeling process. However, because residues of the temporary adhesive layer remained on the substrate during peeling, they could not be completely washed off using the same process as in the Examples. However, by repeating the washing and removing process twice, it was possible to completely remove the residues.
• a temporary adhesive for wafer processing for temporarily bonding a wafer to a support comprising:
• the temporary adhesive for wafer processing is made of a curable silicone resin composition that can be cured by a hydrosilylation reaction,
• the temporary adhesive for wafer processing wherein the curable silicone resin composition contains a phenolic antioxidant that does not contain phosphorus atoms or sulfur atoms.
• the curable silicone resin composition comprises: (A) organopolysiloxane having two or more alkenyl groups per molecule: 100 parts by mass, (B) an organohydrogenpolysiloxane containing two or more hydrogen atoms bonded to silicon atoms (SiH groups) per molecule: an amount such that the sum of the SiH groups in component (B) relative to the sum of the alkenyl groups in component (A) is a molar ratio of 0.3 to 10; (C) non-functional organopolysiloxane: 0.1 to 200 parts by mass, (D) a hydrosilylation reaction catalyst: 0.1 to 5,000 ppm in terms of metal atom weight based on the total weight of components (A), (B), and (C); and (E) The phenol-based antioxidant: 1 to 100,000 ppm based on the total mass of the components (A), (B) and (C).
• [8] A temporary adhesive for wafer processing according to any one of [1] to [7] above, in which, after curing of the curable silicone resin composition containing the phenolic antioxidant, a 180° peel strength of a 25 mm wide test piece against a silicon substrate at 25°C is 2 gf or more and 100 gf or less.
• [9] The temporary adhesive for processing according to any one of [1] to [8] above, in which, after curing of the curable silicone resin composition containing the phenolic antioxidant, the storage modulus at 25°C is 1,000 Pa or more and 1,000 MPa or less.
• [10] A temporary adhesive for wafer processing according to any of [1] to [9] above, in which a laminate is produced by applying a curable silicone resin composition containing the phenolic antioxidant to the wafer, and it is possible to control the peel interface when peeling off the laminate so that it becomes the interface between the temporary adhesive layer obtained from the temporary adhesive for wafer processing and the wafer.
• a wafer laminate comprising a support, a temporary adhesive layer obtained from any one of the temporary adhesives for wafer processing according to [1] to [11] laminated on the support, and a wafer having a circuit-forming surface on its front side and a circuit-free surface on its back side, wherein the temporary adhesive layer is releasably adhered to the front side of the wafer.
• the present invention is not limited to the above-described embodiments.
• the above-described embodiments are merely examples, and anything that has substantially the same configuration as the technical idea described in the claims of the present invention and provides similar effects is included within the technical scope of the present invention.

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• Polymers & Plastics (AREA)
• Adhesives Or Adhesive Processes (AREA)
• Container, Conveyance, Adherence, Positioning, Of Wafer (AREA)

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• 2024
  • 2024-03-08 JP JP2025506823A patent/JPWO2024190702A1/ja active Pending
  • 2024-03-08 CN CN202480017683.3A patent/CN120769897A/zh active Pending
  • 2024-03-08 KR KR1020257029970A patent/KR20250158764A/ko active Pending
  • 2024-03-08 EP EP24770808.4A patent/EP4678711A1/en active Pending
  • 2024-03-08 WO PCT/JP2024/009178 patent/WO2024190702A1/ja not_active Ceased
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