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
  • 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
• • 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
  • H10P52/00—Grinding, lapping or polishing of wafers, substrates or parts of devices
  • H10P52/40—Chemomechanical polishing [CMP]
  • H10P52/402—Chemomechanical polishing [CMP] of semiconductor materials
• • 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
• • 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
  • H10P72/7412—Handling or holding of wafers, substrates or devices during manufacture or treatment thereof for supporting or gripping using temporarily an auxiliary support the auxiliary support including means facilitating the separation of a device or wafer from the auxiliary support
• • 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
• • 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
  • C09J2301/30—Additional features of adhesives in the form of films or foils characterized by the chemical, physicochemical or physical properties of the adhesive or the carrier
  • C09J2301/304—Additional features of adhesives in the form of films or foils characterized by the chemical, physicochemical or physical properties of the adhesive or the carrier the adhesive being heat-activatable, i.e. not tacky at temperatures inferior to 30°C
• • 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

Definitions

• the present invention relates to a method for manufacturing a thin wafer, a wafer stack, and a temporary adhesive for wafer processing used therein.
• 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.
• a technology has been proposed that uses a silicone adhesive as a temporary adhesive layer.
• a hydrosilylation addition curing type silicone adhesive is used to adhere a substrate to a support, and when peeling, the substrate is separated from the support by immersing it in an agent that dissolves or decomposes the silicone resin (Patent Document 3).
• Patent Document 3 an agent that dissolves or decomposes the silicone resin
• hydrosilylation addition cure type silicone adhesive compositions tend to thicken over time during long-term storage, which means that the resin thickness changes when applied to a wafer, posing an issue with the long-term storage stability of the composition.
• the substrate surface may be treated or coated in advance with an oxide film, nitride film, organic resin film, etc., but depending on the type of chemical modification of the substrate surface, this can affect the hydrosilylation reaction caused by the platinum catalyst, resulting in changes in the adhesion between the silicone resin and the substrate, and problems such as inability to obtain stable wafer processability or peelability of the support.
• the present invention has been made in consideration of the above problems, and aims to provide a method for manufacturing thin wafers using a temporary adhesive for wafer processing, a wafer laminate, and a temporary adhesive for wafer processing, which have sufficient substrate retention after bonding even when a substrate with a high step is used, are highly compatible with the wafer back grinding process, TSV formation process, and wafer back wiring process, have excellent wafer thermal process resistance, and have excellent long-term storage stability of the composition, and also exhibit stable substrate retention, peelability, and substrate residue cleanability after peeling for any substrate.
• the present invention provides a method for producing a thin wafer, which uses a thermosetting silicone resin composition as a temporary adhesive for wafer processing for temporarily adhering a wafer to a support, characterized in that the thermosetting silicone resin composition is capable of being cured by heating alone and contains the following components: (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 0.3 to 10 in terms of molar ratio; (C) Organic peroxide: 0.01 to 20 parts by mass (D) Radical-activated hydrosilylation reaction catalyst: 0.1 to 5,000 ppm in terms of metal atom weight based on the total mass of the components (A) and (
• the thin wafer manufacturing method of the present invention can be applied to a wide range of semiconductor film formation processes due to the flexibility and excellent heat resistance of silicone resin, and has excellent CVD (chemical vapor deposition) resistance.
• a temporary adhesive layer with high film thickness uniformity can be formed even on wafers with steps, and this film thickness uniformity makes it easy to manufacture uniform thin wafers of 50 ⁇ m or less.
• the wafer can be easily peeled off from the support, for example at room temperature, and the peeling interface can be controlled between the wafer/temporary adhesive layer, making it easy to clean residues on the wafer after peeling, and improving the manufacturing workability of thin wafers that are prone to cracking.
• thermosetting silicone resin composition that further contains 0.1 to 200 parts by mass of a non-functional organopolysiloxane as component (E).
• thermosetting silicone resin composition further containing a non-functional organopolysiloxane as component (E) can be easily peeled off in the process of peeling the support from the substrate, while preventing the wafer from peeling off during wafer processing such as wafer back grinding and subsequent heat treatment, thereby achieving durability in wafer processing.
• the non-functional organopolysiloxane of component (E) is made of dimethylpolysiloxane, and that the viscosity of a 30% by weight toluene solution at 25°C is 100 to 500,000 mPa ⁇ s. This viscosity is more preferably 1,000 to 400,000 mPa ⁇ s, and even more preferably 10,000 to 300,000 mPa ⁇ s.
• the non-functional organopolysiloxane 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 in wafer thermal processes such as CVD, and it is preferable because it has good workability and coatability.
• the organic peroxide is at least one selected from the group consisting of diacyl peroxides, peroxy esters, dialkyl peroxides, percarbonates, peroxy ketals, hydroperoxides, and ketone peroxides.
• organic peroxides are preferred for use in the present invention in order to obtain the catalytic activity of component (D).
• the organic peroxide has a half-life of 10 hours at a temperature of 40°C or higher and a half-life of 1 minute at a temperature of 200°C or lower.
• thermosetting silicone resin composition that 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) and (B).
• reaction inhibitor can prevent the composition from thickening or gelling during long-term storage.
• thermosetting silicone resin composition after curing, has a 180° peel strength of 2 gf or more and 500 gf or less when used on a silicon substrate at 25°C for a 25 mm wide test piece.
• thermosetting silicone resin composition that has such peel strength after curing, there is no risk of the wafer becoming misaligned during wafer grinding, and the support can be easily peeled off.
• thermosetting silicone resin composition has a storage modulus of 1,000 Pa or more and 1,000 MPa or less at 25°C after curing.
• thermosetting silicone resin composition with such a storage modulus prevents the wafer from shifting during wafer grinding and also ensures stability during thermal processing of the wafer.
• the present invention also provides a method for producing any one of the above-mentioned thin wafers, comprising the steps of: (a) peelably adhering a circuit-forming surface of a wafer having a circuit-forming surface on a front surface and a circuit-free surface on a back surface of the wafer to a support using the temporary adhesive for wafer processing to form a wafer laminate; (b) thermally 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 temporary adhesive for wafer processing that is applicable to thin wafers or wafer laminates, the temporary adhesive for wafer processing being characterized in that it comprises a thermosetting silicone resin composition containing the following components: (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 0.3 to 10 in terms of molar ratio; (C) Organic peroxide: 0.01 to 20 parts by mass (D) Radical-activated hydrosilylation reaction catalyst: 0.1 to 5,000 ppm in terms of metal atom weight based on the total mass of the components (A) and (B)
• the temporary adhesive for wafer processing of the present invention can be applied to a wide range of semiconductor film formation processes due to the flexibility and excellent heat resistance of the silicone resin, and has excellent CVD (chemical vapor deposition) resistance.
• a temporary adhesive layer with high film thickness uniformity can be formed even on wafers with steps, and this film thickness uniformity makes it easy to produce uniform thin wafers of 50 ⁇ m or less.
• the wafer can be easily peeled off from the support, for example at room temperature, and the peeling interface can be controlled between the wafer and the temporary adhesive layer, making it easy to clean residues on the wafer after peeling, improving the manufacturing workability of thin wafers that are prone to cracking.
• the thermosetting silicone resin composition used in the temporary adhesive of the present invention has excellent long-term storage stability, so that the above-mentioned performance can be stably obtained for a long period of time after the composition is produced.
• the composition further comprises a thermosetting silicone resin composition containing 0.1 to 200 parts by mass of a non-functional organopolysiloxane as component (E).
• Such a temporary adhesive for wafer processing further containing a non-functional organopolysiloxane as component (E) can be easily peeled off in the process of peeling the support from the substrate, while preventing the wafer from peeling off during wafer processing such as wafer back grinding and subsequent heat treatment, thereby achieving durability in wafer processing.
• the non-functional organopolysiloxane of component (E) is made of dimethylpolysiloxane, and that the viscosity of a 30% by weight toluene solution at 25°C is 100 to 500,000 mPa ⁇ s. This viscosity is more preferably 1,000 to 400,000 mPa ⁇ s, and even more preferably 10,000 to 300,000 mPa ⁇ s.
• the non-functional organopolysiloxane 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 in wafer thermal processes such as CVD, and it is preferable because it has good workability and coatability.
• the organic peroxide is at least one selected from the group consisting of diacyl peroxides, peroxy esters, dialkyl peroxides, percarbonates, peroxy ketals, hydroperoxides, and ketone peroxides.
• organic peroxides are preferred for use in the present invention in order to obtain the catalytic activity of component (D).
• the organic peroxide has a half-life of 10 hours at a temperature of 40°C or higher and a half-life of 1 minute at a temperature of 200°C or lower.
• thermosetting silicone resin composition further contains, as component (F), a hydrosilylation reaction inhibitor in an amount of 0.001 to 10 parts by mass relative to the total mass of components (A) and (B).
• reaction inhibitor can prevent the composition from thickening or gelling during long-term storage.
• the 180° peel strength of a 25 mm wide test piece against a silicon substrate at 25°C is 2 gf or more and 500 gf or less.
• thermosetting silicone resin composition that has such peel strength after curing eliminates the risk of wafer misalignment during wafer grinding and also makes it easier to peel off the support.
• the storage modulus of the thermosetting silicone resin composition at 25°C after curing is 1,000 Pa or more and 1,000 MPa or less.
• thermosetting silicone resin composition with such a storage modulus prevents the wafer from shifting during wafer grinding and is stable during thermal processing of the wafer.
• 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 thereon, 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 uses a temporary adhesive for wafer processing, which is flexible and has excellent heat resistance of silicone resin, and can be applied to a wide range of semiconductor film formation processes. It also has excellent CVD (chemical vapor deposition) resistance.
• a temporary adhesive layer with high film thickness uniformity can be formed even on wafers with steps, and this film thickness uniformity makes it easy to provide uniform thin wafers of 50 ⁇ m or less.
• the wafer After producing a thin wafer from the wafer laminate, the wafer can be easily peeled off from the support, for example at room temperature, and the peeling interface can be controlled between the wafer and the temporary adhesive layer, which makes it easy to clean off residues on the wafer after peeling, improving the manufacturing workability of thin wafers that are prone to cracking.
• the thin wafer manufacturing method, wafer laminate, and temporary adhesive for wafer processing of the present invention can be applied to a wide range of semiconductor film formation processes due to the flexibility and excellent heat resistance of the silicone resin, and also has excellent CVD (chemical vapor deposition) resistance.
• a temporary adhesive layer with high film thickness uniformity can be formed even on wafers with steps, and due to this film thickness uniformity, it is possible to easily manufacture uniform thin wafers of 50 ⁇ m or less.
• the wafer After the thin wafer is manufactured, the wafer can be easily peeled off from the support, for example at room temperature, and the peeling interface can be controlled between the wafer/temporary adhesive layer, making it easy to clean residues on the wafer after peeling, and improving the manufacturing workability of thin wafers that are prone to cracking. Furthermore, since the thermosetting silicone resin composition used in the temporary adhesive of the present invention has excellent long-term storage stability, it is possible to obtain the above-mentioned stable performance for a long period of time after the composition is manufactured.
• the surface of the wafer to which it is applied is a substrate coated with a resin film or the like, it is not easily affected by the surface coating, and it is possible to show stable wafer adhesion, wafer peelability, and wafer residue cleaning removability for substrates of a wide range of materials.
• thermosetting silicone resin composition that uses a radical-activated hydrosilylation reaction catalyst as a temporary adhesive, and thus completed the present invention.
• thermosetting silicone resin composition shown below.
• the thermosetting silicone resin composition it is preferable for the thermosetting silicone resin composition to have good spin-coatability.
• the present invention is a method for producing a thin wafer that uses a thermosetting silicone resin composition as a temporary adhesive for wafer processing for temporarily adhering a wafer to a support, characterized in that the thermosetting silicone resin composition is capable of being cured by heating alone and contains the following components: (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 0.3 to 10 in terms of molar ratio; (C) Organic peroxide: 0.01 to 20 parts by mass (D) Radical-activated hydrosilylation reaction catalyst: 0.1 to 5,000 ppm in terms of metal atom weight based on the total mass of the components (A) and (B)
• the present invention also provides a temporary adhesive for wafer processing that is applicable to thin wafers or wafer laminates, the temporary adhesive for wafer processing being characterized in that it comprises a thermosetting silicone resin composition containing the following components: (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 0.3 to 10 in terms of molar ratio; (C) Organic peroxide: 0.01 to 20 parts by mass (D) Radical-activated hydrosilylation reaction catalyst: 0.1 to 5,000 ppm in terms of metal atom weight based on the total mass of the components (A) and (B)
• thermosetting silicone resin composition The components that make up the above-mentioned thermosetting silicone resin composition are explained below.
• 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 0.5 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 can be sufficiently high, and the temporary adhesive layer can be cured more reliably. Furthermore, if the molar ratio is 10 or less, the crosslink density can be made appropriate, sufficient adhesive strength and tack can be obtained, and changes in adhesion before and after the heat treatment process can be suppressed.
• Component (C) is an organic peroxide, and the radicals generated by thermal decomposition act on component (D), which will be described later; a radical-activated hydrosilylation reaction catalyst, to obtain catalytic activity.
• the organic peroxide include diacyl peroxides, peroxy esters, dialkyl peroxides, percarbonates, peroxy ketals, hydroperoxides, and ketone peroxides. These may be used alone or in combination of two or more.
• the organic peroxide of component (C) preferably has a 10-hour half-life temperature of 40°C or higher and a 1-minute half-life temperature of 200°C or lower, and more preferably has a 10-hour half-life temperature of 60°C or higher and a 1-minute half-life temperature of 180°C or lower.
• the upper limit of the 10-hour half-life temperature and the lower limit of the 1-minute half-life temperature are approximately 150°C or lower and 100°C or higher, respectively.
• diacyl peroxides examples include isobutyl peroxide, 2,4-dichlorobenzoyl peroxide, 3,5,5-trimethylhexanoyl peroxide, octanoyl peroxide, lauroyl peroxide, stearoyl peroxide, succinic peroxide, benzoylperoxytoluene, and benzoyl peroxide.
• Peroxy esters include, for example, cumyl peroxy neodecanoate, 1,1,3,3-tetramethylbutyl peroxy neodecanoate, 1-cyclohexyl-1-methylethyl peroxy neodecanoate, t-hexyl peroxy neodecanoate, t-amyl peroxy pivalate, t-butyl peroxy pivalate, 1,1,3,3-tetramethylbutyl peroxy 2-ethylhexanoate, 2,5-dimethyl-2,5-bis(2-ethylhexanoylperoxy)hexane, 1-cyclohexyl-1-methylethyl peroxy 2-ethylhexanoate, t-hexyl peroxy 2-ethylhexanoate, and t-butyl peroxy 2-ethyl.
• dialkyl peroxides examples include ⁇ , ⁇ '-bis(t-butylperoxy)diisopropylbenzene, dicumyl peroxide, 2,5-dimethyl-2,5-bis(t-butylperoxy)hexane, and t-butylcumyl peroxide.
• percarbonates examples include di-n-propyl peroxydicarbonate, diisopropyl peroxydicarbonate, bis(4-t-butylcyclohexyl)peroxydicarbonate, di-2-ethoxymethoxyperoxydicarbonate, bis(2-ethylhexylperoxy)dicarbonate, dimethoxybutyl peroxydicarbonate, bis(3-methyl-3-methoxybutylperoxy)dicarbonate, and 1,6-di(t-butylperoxycarbonyloxy)hexane.
• Peroxyketals include 1,1-di(t-butylperoxy)cyclohexane and 2,2-bis[4,4-di(t-butylperoxy)cyclohexyl]propane.
• Hydroperoxides include diisopropylbenzene hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, cumyl hydroperoxide, t-butyl hydroperoxide, and t-amyl hydroperoxide.
• Ketone peroxides include methyl ethyl ketone peroxide and acetylacetone peroxide.
• the amount of organic peroxide added in component (C) is 0.01 to 20 parts by mass, preferably 0.05 to 10 parts by mass, per 100 parts by mass of the total amount of organopolysiloxane in component (A). If this amount is 0.01 parts by mass or more, the reaction can proceed sufficiently and the desired cured product can be obtained more reliably. If this amount is 20 parts by mass or less, foaming of the resin during curing can be prevented.
• Component (D) is a radical-activated hydrosilylation reaction catalyst that exhibits catalytic activity through reaction with radicals generated by thermal decomposition of component (C), and as a result, is a catalyst that has the effect of promoting the addition reaction between alkenyl groups in component (A) and Si-H groups in component (B).
• Radically activated hydrosilylation reaction catalysts are primarily platinum group metal catalysts or iron group metal catalysts.
• Platinum group metal catalysts include platinum, palladium, and rhodium-based metal complexes
• iron group metal catalysts include nickel, iron, and cobalt-based iron group complexes. Of these, platinum metal complexes are preferred and often used because they are relatively easy to obtain and exhibit good catalytic activity.
• catalyst ligands include cyclic diene ligands and ⁇ -diketonato ligands, which provide long-term storage stability at room temperature.
• radically active hydrosilylation reaction catalysts include, as the cyclic diene ligand type, 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
• these catalysts When using these catalysts, if they are solid catalysts they can be used in solid form, but to obtain a more uniform cured product it is preferable to use a solution of the catalyst in a suitable solvent and then dissolve it in the organopolysiloxane having alkenyl groups (A).
• suitable solvents include isononane, n-decane, toluene, and 2-(2-butoxyethoxy)ethyl acetate.
• the amount of component (D) added may be any effective amount, but is usually 0.1 to 5,000 ppm of platinum (calculated as metal atomic weight) relative to the total mass of (A) and (B), preferably 0.5 to 2,000 ppm, and more preferably 1 to 500 ppm. If it is 0.1 ppm or more, the curing properties of the composition will not decrease, the crosslink density will not decrease, and the physical strength of the material will not decrease. If it is 5,000 ppm or less, foaming of the resin during curing can be suppressed.
• the heat-curable silicone resin composition may further comprise a non-functional organopolysiloxane as component (E), where "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 (E) 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 non-functional organopolysiloxane of component (E) preferably has a viscosity (25°C) in a 30% by weight toluene solution of 100 to 500,000 mPa ⁇ s, and more preferably 5,000 to 500,000 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, and it 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 blocked with trimethylsiloxy groups at both molecular chain ends, dimethylsiloxane/3
• the non-functional organopolysiloxane of component (E) 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 (E) component is preferably blended in an amount of 0.1 to 200 parts by mass, and more preferably 1 to 100 parts by mass, per 100 parts by mass of the (A) component. If this blending ratio is 0.1 parts by mass or more, it is preferable because it allows for easy peeling, particularly in the process of peeling the support from the substrate. Also, if this blending ratio is 200 parts by mass or less, it 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.
• thermosetting 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 during preparation of the composition, application to a substrate, or storage.
• 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.
• thermosetting silicone resin composition contains component (F), the control ability differs depending on the chemical structure, so the content should be adjusted to the optimum amount for each. Taking into consideration the effects on curability, storage stability, and physical properties after curing, 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) and (B). 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 thermosetting silicone resin composition may further contain an organopolysiloxane containing R A 3 SiO 0.5 units (wherein R A are each independently an unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms) and SiO 2 units, 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 thermosetting silicone resin composition to further improve the heat resistance of the resulting temporary adhesive layer.
• thermosetting 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 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 includes a method in which the thermosetting 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 (A) is diluted with a solvent in advance to improve workability and mixability, and then the remaining components are mixed.
• the mixing method used to make the solution can 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 thermosetting silicone resin composition.
• the temporary adhesive layer can be formed by applying the thermosetting silicone resin composition onto a substrate by a method such as spin coating or roll coating.
• a method such as spin coating or roll coating.
• the viscosity of the dissolved thermosetting silicone resin composition at 25°C is preferably 1 to 100,000 mPa ⁇ s, and more preferably 10 to 10,000 mPa ⁇ s.
• thermosetting silicone resin composition has a 180° peel strength of a 25 mm wide test piece (e.g., a glass test piece) at 25°C after curing of typically 10 to 500 gf, preferably 20 to 400 gf, and more preferably 30 to 300 gf. If it is 10 gf or more, there is no risk of the wafer slipping during wafer grinding, and if it is 500 gf or less, the wafer can be easily peeled off.
• the thermosetting silicone resin composition has a storage modulus at 25°C after curing of 1,000 Pa or more and 1,000 MPa or less, preferably 10,000 Pa or more and 100 MPa or less. If the storage modulus is 1,000 Pa or more, the 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 radical-activated hydrosilylation catalyst, component (D), used in the thermosetting silicone resin composition also has UV activity, so it is preferable to store the resin composition in a cool, dark place. It is also preferable to use a light-blocking container for the filling. This prevents the composition from thickening or hardening even during long-term storage, and makes it possible to maintain stable properties over long periods of time that are equivalent to those immediately after production.
• the present invention provides a wafer laminate using the above-mentioned temporary adhesive for wafer processing.
• the wafer laminate of the present invention is a wafer laminate comprising a support, a temporary adhesive layer obtained from the above-mentioned temporary adhesive for wafer processing laminated thereon, and a wafer having a circuit-forming surface on its front side and a circuit-free surface on its back side, in which the temporary adhesive layer is releasably adhered to the front side of the wafer.
• the method for producing a thin wafer of the present invention is characterized in that a temporary adhesive for wafer processing comprising the above-mentioned thermosetting silicone resin composition is used to temporarily bond a wafer having semiconductor circuits 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.
• temporary adhesion can be achieved by 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 together via the temporary adhesive layer.
• temporary adhesion can be achieved by forming a temporary adhesive layer on the surface of the support using the temporary adhesive for wafer processing, and bonding the support and the surface of the wafer together 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, but is not limited to, a substrate such as a silicon wafer, a glass plate, or a quartz wafer. In the present invention, it is not necessary to irradiate the temporary adhesive layer with radiant energy rays through the support, and the support may not be light-transmitting.
• the temporary adhesive layer may be formed by laminating a film of the thermosetting silicone resin composition on a wafer or support, or by applying the thermosetting silicone resin composition by a method such as spin coating or roll coating.
• the thermosetting silicone resin composition is a solution containing a solvent, after application, it is prebaked 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 40 to 200°C, more preferably 50 to 150°C.
• the pressure applied when bonding the wafer with the temporary adhesive layer formed thereon and the support varies depending 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 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 thermally curing the temporary adhesive layer. After forming the wafer laminate, 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.
• Step (c) is a step of grinding or polishing the non-circuit forming surface of the wafer 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.
• 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.
• Wafer cleaning methods include washing with a paddle using the above-mentioned cleaning solution, washing by spraying, and immersion in a cleaning solution tank.
• the temperature during washing is preferably 10 to 80°C, more preferably 15 to 65°C. If necessary, after dissolving the temporary adhesive layer with these cleaning solutions, a final rinse with water or alcohol and drying process may be performed.
• 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 a radical-activated hydrosilylation reaction catalyst; (methylcyclopentadienyl)trimethylplatinum (IV) toluene solution (platinum concentration 1.0 mass%) and 0.1 parts by mass of 1,6-di(t-butylperoxycarbonyloxy)hexane (manufactured by Kayaku Nouryon Co., Ltd., product name; Kayalen 6-70, 10-hour half-life temperature; 97°C, 1-minute half-life temperature; 150°C) were added thereto, and the mixture was filtered through a 0.2 ⁇ m membrane filter to prepare a thermosetting silicone resin solution A1.
• a radical-activated hydrosilylation reaction catalyst methylcyclopentadienyl)trimethylplatinum (IV) toluene solution (platinum concentration 1.0 mass%)
• 1,6-di(t-butylperoxycarbonyloxy)hexane manufactured by Kayaku Nouryon Co., Ltd
• the half-life temperature of an organic peroxide is the half-life period during which the organic peroxide is decomposed by heat and the amount of active oxygen therein is reduced to half the amount before the decomposition, and the half-life period was determined by preparing a benzene solution of an organic peroxide with a concentration of 0.1 mol/L and measuring the change over time in the organic peroxide concentration when the solution was thermally decomposed.
• the viscosity of the resin solution A1 at 25°C was 2,300 Pa ⁇ s.
• 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 unit mol %/100)] ⁇ > ⁇ (M Vi unit mol %/100)
• Amount of Si-H from POHS (mol) (POHS addition amount/POHS molecular weight) ⁇ PVMS
• a radical-activated hydrosilylation reaction catalyst (methylcyclopentadienyl)trimethylplatinum (IV) toluene solution (platinum concentration 1.0 mass%) and 0.07 parts by mass of t-butylperoxy-2-ethylhexyl monocarbonate (manufactured by Kayaku Nouryon Co., Ltd., product name: Trigonox 117, 10-hour half-life temperature: 98°C, 1-minute half-life temperature: 156°C) were 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 the 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 solutions [Examples 1 to 4, Comparative Examples 1 and 2] The thermosetting silicone resin solutions obtained in Preparation Examples 1 to 4 and Comparative Preparation Examples 1 and 2 were applied to a silicon substrate and the film thickness was measured (1) immediately after preparation and (2) after storage at 50°C for one month under light-shielding and sealed conditions.
• the silicon substrate was a silicon wafer having a diameter of 200 mm and a thickness of 725 ⁇ m.
• the thermosetting silicone resin solutions A1 to A4, C1, and C2 were spin-coated, and the silicon wafer was heated on a hot plate at 100°C for 2 minutes and then at 180°C for 30 minutes to produce a silicone resin cured film.
• the film thickness of the cured film was measured using F50 manufactured by Filmetrics. The results are shown in Table 1.
• thermosetting silicone resin solution of this embodiment has excellent long-term storage stability.
• a 200 mm diameter (thickness: 500 ⁇ m) glass plate was used as a support, and the silicon wafer and glass plate having the temporary adhesive layer were vacuum bonded at 100 ° C., 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 plate were joined together to produce a wafer laminate.
• a glass plate was used as the support in order to visually check for abnormalities after bonding of the substrate, but a silicon substrate that does not transmit light, such as a wafer, can also be used.
• this comparative example is the influence of the organic resin film on the wafer
• a wafer without the organic resin film coating was used, and the C1 solution prepared in Comparative Preparation Example 1 was evaluated in the same manner as above, and this was used as the reference example.
• CVD resistance test (2) After completing the back grinding resistance test, the wafer stack was introduced into a CVD device, and a 2 ⁇ m SiO 2 film deposition experiment was performed, and the presence or absence of appearance abnormalities was checked by visual observation. When no appearance abnormalities occurred, they were evaluated as good and indicated with " ⁇ ", and when appearance abnormalities such as voids, wafer bulges, and wafer breakage occurred, they were evaluated as bad and indicated with " ⁇ ".
• the peelability of the substrate was evaluated by first attaching a dicing tape (ELP UB-3083D, manufactured by Nitto Denko Corporation) to the wafer side of the wafer laminate that had undergone the (3) CVD resistance test using a dicing frame, and then setting the dicing tape surface on an adsorption plate by vacuum adsorption. Thereafter, at room temperature, the glass substrate was peeled off by lifting one point on the glass with tweezers. A case in which the 50 ⁇ m-thick wafer could be peeled off without cracking was indicated by " ⁇ ", and a case in which an abnormality such as cracking occurred was evaluated as defective and indicated by "X".
• a dicing tape ELP UB-3083D, manufactured by Nitto Denko Corporation
• thermosetting silicone resin solutions A1 to A4, C1, and C2 were spin-coated, and the wafer was heated on a hot plate at 100° C. for 2 minutes to form a silicone resin layer on the glass substrate with the film thickness shown in Tables 2 and 3.
• the silicone resin layer was then cured in an oven at 180° C. for 1 hour and cooled to room temperature.
• the glass substrate containing the obtained silicone resin layer was subjected to elastic modulus measurement under conditions of 25° C., 1 Hz, and 1% strain using Ares G2 manufactured by TA Instruments, with the silicone resin layer sandwiched between 25 mm aluminum plates so that a load of 50 gf was applied to the silicone resin layer, and the obtained elastic modulus value was taken as the storage elastic modulus of the silicone resin layer.
• the wafer laminates of Examples 5 to 9, which include the temporary adhesive layer of the present invention were confirmed to have sufficient processing durability, easy peelability, and excellent residue cleaning removability on the wafer after peeling, even on wafers that have an organic resin coating on the wafer.
• the temporary adhesives of Comparative Examples 3 to 5, which used a conventional platinum addition curing resin composition resulted in peeling problems, especially in wafer processability, due to the influence of the organic resin coating on the wafer.
• thermosetting silicone resin composition as a temporary adhesive for wafer processing for temporarily adhering a wafer to a support, comprising: A method for producing a thin wafer, characterized in that the thermosetting silicone resin composition can be cured by heating alone and contains the following components: (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 0.3 to 10 in terms of molar ratio; (C) Organic peroxide: 0.01 to 20 parts by mass (D) Radical-activated hydrosilylation reaction catalyst: 0.1 to 5,000 ppm in terms of metal atom weight based on the total mass
• [3] The method for producing a thin wafer according to [2] above, wherein the non-functional organopolysiloxane of component (E) is made of dimethylpolysiloxane, and the viscosity of a 30% by weight toluene solution at 25°C is 100 to 500,000 mPa ⁇ s.
• [4] The method for producing a thin wafer according to any one of [1] to [3] above, wherein the organic peroxide is at least one selected from the group consisting of diacyl peroxides, peroxy esters, dialkyl peroxides, percarbonates, peroxy ketals, hydroperoxides and ketone peroxides.
• [5] The method for manufacturing a thin wafer according to any one of [1] to [4] above, wherein the organic peroxide has a half-life of 10 hours at a temperature of 40°C or higher and a half-life of 1 minute at a temperature of 200°C or lower.
• [6] The method for producing a thin wafer according to any one of [1] to [5] above, further comprising using a thermosetting silicone resin composition which further contains, as component (F), a hydrosilylation reaction inhibitor in an amount of 0.001 to 10 parts by mass, based on the total mass of components (A) and (B).
• thermosetting silicone resin composition after curing, has a 180° peel strength of a 25 mm wide test piece from a silicon substrate at 25° C. of 2 gf or more and 500 gf or less.
• heat-curable silicone resin composition has a storage modulus at 25° C. of 1,000 Pa or more and 1,000 MPa or less after curing.
• a temporary adhesive for wafer processing applicable to a thin wafer or wafer stack characterized in that the temporary adhesive for wafer processing is made of a thermosetting silicone resin composition containing the following components: (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 0.3 to 10 in terms of molar ratio; (C) Organic peroxide: 0.01 to 20 parts by mass (D) Radical-activated hydrosilylation reaction catalyst: 0.1 to 5,000 ppm in terms of metal atom weight based on the total mass of the components (A) and (B) [11]: The temporary adhesive for wafer processing according to the above [10], which comprises a thermosetting silicone resin composition further
• [14] The temporary adhesive for wafer processing according to any one of [10] to [13], wherein the organic peroxide has a half-life of 10 hours at a temperature of 40° C. or higher and a half-life of 1 minute at a temperature of 200° C. or lower.
• a wafer laminate comprising a support, a temporary adhesive layer obtained from the temporary adhesive for wafer processing according to any one of [10] to [17] laminated thereon, and a wafer having a circuit-forming surface on its front side and a circuit-free surface on its back side, wherein the temporary adhesive layer is releasably adhered to the front side of the wafer.
• 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 exhibits similar effects is included within the technical scope of the present invention.

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Adhesives Or Adhesive Processes (AREA)
• Mechanical Treatment Of Semiconductor (AREA)

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• 2024
  • 2024-03-08 JP JP2025506821A patent/JPWO2024190700A1/ja active Pending
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  • 2024-03-08 EP EP24770806.8A patent/EP4679493A1/en active Pending
  • 2024-03-08 KR KR1020257029974A patent/KR20250160444A/ko active Pending
  • 2024-03-08 WO PCT/JP2024/009173 patent/WO2024190700A1/ja not_active Ceased

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