WO2015152010A1 - Protective film, and production method for semiconductor device using protective film - Google Patents

Protective film, and production method for semiconductor device using protective film Download PDF

Info

Publication number
WO2015152010A1
WO2015152010A1 PCT/JP2015/059459 JP2015059459W WO2015152010A1 WO 2015152010 A1 WO2015152010 A1 WO 2015152010A1 JP 2015059459 W JP2015059459 W JP 2015059459W WO 2015152010 A1 WO2015152010 A1 WO 2015152010A1
Authority
WO
WIPO (PCT)
Prior art keywords
protective film
semiconductor wafer
adhesive layer
grinding
heating
Prior art date
Application number
PCT/JP2015/059459
Other languages
French (fr)
Japanese (ja)
Inventor
誠 助川
木下　仁
田原　修二
Original Assignee
三井化学東セロ株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 三井化学東セロ株式会社 filed Critical 三井化学東セロ株式会社
Priority to JP2016511600A priority Critical patent/JP6106332B2/en
Priority to CN201580007736.4A priority patent/CN105981137B/en
Publication of WO2015152010A1 publication Critical patent/WO2015152010A1/en

Links

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
    • C09J133/00—Adhesives based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides, or nitriles thereof; Adhesives based on derivatives of such polymers
    • C09J133/04—Homopolymers or copolymers of esters
    • C09J133/06—Homopolymers or copolymers of esters of esters containing only carbon, hydrogen and oxygen, the oxygen atom being present only as part of the carboxyl radical
    • C09J133/062—Copolymers with monomers not covered by C09J133/06
    • C09J133/068—Copolymers with monomers not covered by C09J133/06 containing glycidyl 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
    • C09J133/00—Adhesives based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides, or nitriles thereof; Adhesives based on derivatives of such polymers
    • C09J133/04—Homopolymers or copolymers of esters
    • C09J133/06—Homopolymers or copolymers of esters of esters containing only carbon, hydrogen and oxygen, the oxygen atom being present only as part of the carboxyl radical
    • C09J133/062—Copolymers with monomers not covered by C09J133/06
    • C09J133/066—Copolymers with monomers not covered by C09J133/06 containing -OH 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
    • C09J7/00—Adhesives in the form of films or foils
    • C09J7/20—Adhesives in the form of films or foils characterised by their carriers
    • C09J7/22—Plastics; Metallised plastics
    • 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
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/67—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere
    • H01L21/683—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere for supporting or gripping
    • H01L21/6835—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere for supporting or gripping using temporarily an auxiliary support
    • H01L21/6836—Wafer tapes, e.g. grinding or dicing support tapes
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F220/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride ester, amide, imide or nitrile thereof
    • C08F220/02—Monocarboxylic acids having less than ten carbon atoms; Derivatives thereof
    • C08F220/10—Esters
    • C08F220/12—Esters of monohydric alcohols or phenols
    • C08F220/16—Esters of monohydric alcohols or phenols of phenols or of alcohols containing two or more carbon atoms
    • C08F220/18—Esters of monohydric alcohols or phenols of phenols or of alcohols containing two or more carbon atoms with acrylic or methacrylic acids
    • C08F220/1802—C2-(meth)acrylate, e.g. ethyl (meth)acrylate
    • 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
    • C08K5/0025—Crosslinking or vulcanising agents; including accelerators
    • 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
    • C09J2301/40—Additional features of adhesives in the form of films or foils characterized by the presence of essential components
    • C09J2301/408—Additional features of adhesives in the form of films or foils characterized by the presence of essential components additives as essential feature of the adhesive layer
    • 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
    • C09J2433/00—Presence of (meth)acrylic polymer
    • 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
    • C09J2479/00—Presence of polyamine or polyimide
    • C09J2479/08—Presence of polyamine or polyimide polyimide
    • C09J2479/086—Presence of polyamine or polyimide polyimide in the substrate
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2221/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof covered by H01L21/00
    • H01L2221/67—Apparatus for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components; Apparatus not specifically provided for elsewhere
    • H01L2221/683—Apparatus for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components; Apparatus not specifically provided for elsewhere for supporting or gripping
    • H01L2221/68304—Apparatus for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components; Apparatus not specifically provided for elsewhere for supporting or gripping using temporarily an auxiliary support
    • H01L2221/68327—Apparatus for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components; Apparatus not specifically provided for elsewhere for supporting or gripping using temporarily an auxiliary support used during dicing or grinding
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2221/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof covered by H01L21/00
    • H01L2221/67—Apparatus for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components; Apparatus not specifically provided for elsewhere
    • H01L2221/683—Apparatus for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components; Apparatus not specifically provided for elsewhere for supporting or gripping
    • H01L2221/68304—Apparatus for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components; Apparatus not specifically provided for elsewhere for supporting or gripping using temporarily an auxiliary support
    • H01L2221/6834—Apparatus for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components; Apparatus not specifically provided for elsewhere for supporting or gripping using temporarily an auxiliary support used to protect an active side of a device or wafer
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2221/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof covered by H01L21/00
    • H01L2221/67—Apparatus for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components; Apparatus not specifically provided for elsewhere
    • H01L2221/683—Apparatus for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components; Apparatus not specifically provided for elsewhere for supporting or gripping
    • H01L2221/68304—Apparatus for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components; Apparatus not specifically provided for elsewhere for supporting or gripping using temporarily an auxiliary support
    • H01L2221/68381—Details of chemical or physical process used for separating the auxiliary support from a device or wafer
    • H01L2221/68386—Separation by peeling

Definitions

  • the present invention relates to a protective film and a method for manufacturing a semiconductor device using the protective film. Specifically, the present invention relates to a protective film that is used in a manufacturing process of a semiconductor device such as a discrete device or an IGBT element and protects a circuit forming surface of a semiconductor wafer, and a method of manufacturing a semiconductor device using the protective film.
  • wafer backside a step of grinding a circuit non-formed surface of a semiconductor wafer (hereinafter referred to as “wafer backside” as appropriate), a step of etching a work-affected layer on the backside of a wafer with a chemical solution, Various processes are performed on the back side of the wafer, such as a step of forming a metal electrode on the back side of the wafer, and in the case of an IGBT element, a step of ion implantation into the back side of the wafer and an annealing step of activating the implanted dopant.
  • an adhesive layer is applied to the circuit forming surface of the semiconductor wafer (hereinafter referred to as “wafer surface” as appropriate) in order to prevent damage and contamination of the semiconductor wafer.
  • wafer surface the circuit forming surface of the semiconductor wafer
  • a protective film with is attached.
  • Examples of such a protective film include the following.
  • Japanese Patent Application Laid-Open No. 2010-287819 discloses that “an intermediate resin layer formed by curing an intermediate resin layer composition containing an adhesive component and a curing component on a base film and a radiation curable adhesive layer”
  • a semiconductor wafer processing pressure-sensitive adhesive tape in which and are laminated in this order is disclosed.
  • Japanese Patent Application Laid-Open No. 2011-249608 discloses that “a pressure-sensitive adhesive tape for protecting a semiconductor wafer surface comprising a pressure-sensitive adhesive layer made of a radiation-curable resin composition on a base resin film containing a polyester resin”. Is disclosed.
  • the film provided with the adhesive layer is a film for sticking to a semiconductor to protect it during the processing of the semiconductor having a reduced pressure heating process.
  • Japanese Patent Application Laid-Open No. 2012-109585 discloses “A semiconductor processing tape is disclosed which includes a pressure-sensitive adhesive layer containing a photocurable pressure-sensitive adhesive, silica fine particles having a specific particle diameter, and a gas generating agent on at least one surface of a substrate.
  • a sheet for fixing a semiconductor wafer whose adhesive strength is reduced by heating for example, in JP-A-10-025456, “sheet-like support and support In the semiconductor wafer fixing sheet, the main part of which is formed of a pressure-sensitive adhesive laminated on top thereof, the main component of the adhesive is 100 parts by weight of the base polymer, 10 to 900 parts by weight of the thermosetting compound, and heat polymerization is started.
  • a semiconductor wafer fixing sheet characterized by being formed with 0.1 to 10 parts by mass of an agent is disclosed.
  • JP-A-8-302301 discloses a thickness of 500 ⁇ m having an oxygen transmission coefficient of “1 ⁇ 10 8 cc ⁇ cm / cm 2 ⁇ sec ⁇ cmHg or more.
  • a heat-peelable pressure-sensitive adhesive sheet formed by forming a curable pressure-sensitive adhesive layer that does not cure or is delayed in the presence of oxygen in the following film-like substrate but is cured by heating is disclosed.
  • the curable pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet is based on 100 parts by weight of the pressure-sensitive rubber resin (A), 50 to 150 parts by weight of the ethylenically unsaturated group-containing compound (B), and 0% of the organic peroxide (C). It is also disclosed that 1 to 15 parts by mass, 0.01 to 5.00 parts by mass of a crosslinking agent (D) and 0.001 to 1.0 parts by mass of a polymerization inhibitor (E) are blended. Yes.
  • This pressure-sensitive adhesive sheet has a feature that it can be easily peeled off by heating.
  • the various processes performed on the wafer back side described above include a step of heating the semiconductor wafer under vacuum.
  • the semiconductor wafer is heated to 200 ° C. or higher under vacuum in a vacuum apparatus.
  • the film may be lifted or peeled off from the semiconductor wafer.
  • the adhesive strength may increase. If the film floats, it may be difficult to convey. That is, the present situation is that a film having a conventional adhesive layer cannot be applied to a process in which heating at 200 ° C. or higher is performed under vacuum.
  • heating at 200 ° C. or higher under vacuum is appropriately referred to as “vacuum heating”.
  • an object of the present invention is to apply a process that is performed under vacuum heating while being adhered to a semiconductor wafer after being adhered to a circuit forming surface of a semiconductor wafer and thermosetting the thermosetting adhesive layer.
  • An object of the present invention is to provide a protective film that, when applied to a method for manufacturing a semiconductor device, suppresses the occurrence of floating while protecting the circuit forming surface of the semiconductor wafer and is excellent in releasability when peeling from the semiconductor wafer. .
  • the other subject of this invention is providing the manufacturing method of the semiconductor device including the process performed under vacuum heating using the said protective film.
  • the means for solving the above-mentioned problems are as follows.
  • a polyimide base material A composition comprising an acrylic polymer (a), a thermal radical generator (b) having a half-life temperature of 140 ° C. or more and 200 ° C. or less, and a crosslinking agent (c) provided on one surface of the polyimide substrate.
  • a thermosetting adhesive layer obtained from the product, A protective film that is attached to a circuit forming surface of a semiconductor wafer.
  • ⁇ 2> The protective film according to ⁇ 1>, wherein the thermal radical generator (b) has a molecular weight of 200 or more and 1000 or less.
  • the thermal radical generator (b) has a molecular weight of 200 or more and 1000 or less.
  • the composition further contains a bifunctional or higher functional acrylic oligomer (d).
  • ⁇ 4> The protective film according to any one of ⁇ 1> to ⁇ 3>, wherein the acrylic polymer (a) is a polymer having a radical-reactive double bond in a side chain.
  • thermosetting adhesive layer is in contact with the circuit forming surface.
  • Pasting process (B) a grinding step of grinding a non-circuit-formed surface of the semiconductor wafer; (C) a heating step of heating the semiconductor wafer to which the protective film is attached and the non-circuit-formed surface is ground at a temperature of 120 ° C. or higher and 180 ° C. or lower; (D) after the heating step of (C), a standing step of standing the semiconductor wafer to which the protective film is stuck under vacuum; (E) After the standing step of (D), under vacuum and at a temperature of 200 ° C.
  • a method for manufacturing a semiconductor device comprising:
  • ⁇ 10> The method according to any one of ⁇ 6> to ⁇ 9>, wherein the grinding step (B) is a step of grinding an inner peripheral portion while leaving an outer peripheral portion of a circuit non-formed surface in the semiconductor wafer.
  • the grinding step (B) is a step of grinding an inner peripheral portion while leaving an outer peripheral portion of a circuit non-formed surface in the semiconductor wafer.
  • a method for manufacturing a semiconductor device including a step of applying a vacuum heating while being attached to a semiconductor wafer after being attached to a circuit forming surface of a semiconductor wafer and thermosetting the thermosetting adhesive layer.
  • a protective film that suppresses the occurrence of floating while protecting the circuit forming surface of the semiconductor wafer and is excellent in releasability when peeling from the semiconductor wafer.
  • the manufacturing method of the semiconductor device including the process performed under vacuum heating using the said protective film can be provided.
  • the protective film of the present invention is a polyimide base and a thermal radical generator (a) provided on one surface of the polyimide base and having an acrylic polymer (a) and a one-minute half-life temperature of 140 ° C. or higher and 200 ° C.
  • thermosetting adhesive layer obtained from a composition containing a crosslinking agent (c), and forming a circuit on a semiconductor wafer It is a protective film affixed to the surface.
  • the thermal radical generator (b) having a one-minute half-life temperature of 140 ° C. or more and 200 ° C. or less contained in the thermosetting adhesive layer is suitable for storage at room temperature or when forming a thermosetting adhesive layer. Decomposition is difficult to start under dry conditions, and it has the property of decomposing even without heating conditions that develop adhesive strength that makes it difficult to peel from the semiconductor wafer. In addition, the polyimide base material is unlikely to be softened by heating, can maintain a high elastic modulus even at a high temperature, has a property such that the thermal expansion coefficient is close to that of a semiconductor wafer, and the thermal contraction ratio is low.
  • the protective film of the present invention is applied to the circuit forming surface of a semiconductor wafer, and the thermosetting adhesive
  • thermosetting the layer it is estimated that it is difficult to expand even at a high temperature, and that it can be a pressure-sensitive adhesive layer (after thermosetting) having peelability from the semiconductor wafer.
  • the protective film of the present invention suppresses the occurrence of floating even when subjected to a process performed in a harsh environment such as under vacuum heating, and protects the circuit forming surface of the semiconductor wafer. Can be continued, and after that, excellent peelability can also be exhibited when peeling from the semiconductor wafer.
  • thermosetting adhesive layer The thermosetting pressure-sensitive adhesive layer in the present invention (hereinafter sometimes abbreviated as “pressure-sensitive adhesive layer”) is an acrylic polymer (a), a one-minute half-life temperature of 140 ° C. or higher and 200 ° C. or lower. It is obtained from the composition containing (b) and a crosslinking agent (c).
  • the acrylic polymer (a) is a binder resin that serves as a base for the pressure-sensitive adhesive in the pressure-sensitive adhesive layer, and can be obtained by copolymerizing several general (meth) acrylic acid ester monomers.
  • the (meth) acrylic acid ester monomer constituting the acrylic polymer (a) those known for pressure-sensitive adhesives can be applied.
  • the acrylic polymer (a) preferably has a high thermal decomposition temperature.
  • an acrylic polymer polymerized from an acrylate monomer is more heat resistant than an acrylic polymer polymerized from a methacrylic acid ester monomer (thermally decomposable). 50 mol% or more) is more preferable.
  • Suitable monomers for obtaining the acrylic polymer (a) are, for example, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, propyl acrylate, propyl methacrylate, butyl acrylate, butyl methacrylate, hexyl acrylate, hexyl.
  • Examples include methacrylate, octyl acrylate, octyl methacrylate, nonyl acrylate, nonyl methacrylate, dodecyl acrylate, dodecyl methacrylate, and the like.
  • the side chain alkyl group of these monomers may be linear or branched. Moreover, you may use together 2 or more types of said acrylic acid alkylester monomers according to the objective.
  • the acrylic polymer (a) preferably has a functional group that reacts with a cross-linking agent (c) described later from the viewpoint of adjusting the properties (eg, adhesiveness) of the adhesive layer.
  • the functional group that reacts with the crosslinking agent (c) of the acrylic polymer (a) is preferably a carboxylic acid group, a hydroxyl group, a glycidyl group, or the like.
  • a carboxylic acid group, a hydroxyl group, a glycidyl group, etc. react with polyisocyanate and polyfunctional epoxy resin which are crosslinking agents (c).
  • a (meth) acrylic acid ester monomer having such a functional group may be copolymerized.
  • the (meth) acrylic acid ester monomer having a functional group that reacts with the crosslinking agent (c) include monomers having a carboxyl group such as acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid, and fumaric acid; And monomers having a hydroxyl group such as ethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate and hydroxypropyl methacrylate; monomers having a glycidyl group such as glycidyl acrylate and glycidyl methacrylate;
  • an acrylic polymer (a) has a radical reactive double bond in a side chain from the point which hardens an adhesion layer.
  • a (meth) acrylic acid ester monomer having such a radical reactive double bond may be added to the copolymerized main polymer side chain.
  • a well-known technique in which glycidyl (meth) acrylate is copolymerized in the main chain, and (meth) acrylic acid is added to the glycidyl group of the main chain as a secondary reaction.
  • the method of making it react; etc. are mentioned.
  • the reaction of acid and glycidyl is more effective than the reaction of isocyanate and hydroxyl group.
  • the acrylic polymer (a) has a radical-reactive double bond in the side chain so that the radicals generated from the specific thermal radical generator (b) react with each other between the acrylic polymers (a).
  • the reaction between the acrylic polymer (a) and the later-described bifunctional or higher acrylic oligomer becomes possible.
  • the acrylic polymer (a) is preferably contained in the composition in the range of 50% by mass to 99.5% by mass, and more preferably in the range of 65% by mass to 99% by mass.
  • the specific thermal radical generator (b) used in the present invention is a component selected from the following points. That is, in the present invention, an adhesive layer formed by dissolving each component (including the acrylic polymer (a), the specific thermal radical generator (b), and the crosslinking agent (c)) used in obtaining the adhesive layer in a solvent.
  • the coating liquid is applied on a polyimide substrate (or separator) and dried to produce a protective film. Since heat is applied during the drying, it is preferable to select a temperature at which the decomposition is difficult to start at the drying temperature. Also, those having a high decomposition temperature are preferable in terms of storage stability at room temperature.
  • the specific thermal radical generator (b) used in the present invention needs to have a one-minute half-life temperature of 140 ° C. or higher and 200 ° C. or lower.
  • the 1 minute half-life temperature of the specific thermal radical generator is preferably 145 ° C. or higher and 180 ° C. or lower.
  • the molecular weight of the specific thermal radical generator is preferably 200 to 1000, more preferably 200 to 700, and further preferably 300 to 700.
  • specific thermal radical generator (b) known peroxides, azo compounds and the like having a 1 minute half-life temperature in the above range are used.
  • Specific examples of the specific thermal radical generator (b) include the following, but the present invention is not limited thereto.
  • a commercial product name (all manufactured by NOF Corporation), molecular weight, and 1-minute half-life temperature are also shown.
  • Specific commercial products of the specific thermal radical generator (b) include, for example, Perhexa MC, Perhexa TMH, Perhexa HC, Perhexa C, Pertetra A, Perhexyl I, Perbutyl 355, Perbutyl L, Perbutyl manufactured by NOF Corporation.
  • E perhexyl Z, perhexa 25Z, perhexa 22, perhexa V, perbutyl P, park mill D, perhexyl D, perhexa 25B, perbutyl C, perhexine 25B, and the like are preferable.
  • the amount of the specific thermal radical generator (b) added is preferably 0.1 parts by mass or more and 5 parts by mass or less with respect to 100 parts by mass of the total amount of monomers constituting the acrylic polymer (a). Preferably they are 0.2 mass part or more and 2 mass parts or less, More preferably, they are 0.3 mass part or more and 1 mass part or less. If the amount of the specific thermal radical generator added is too small, there may be a problem that the adhesive layer is not sufficiently cured by heat and the tackiness is increased.
  • XPS X-ray photoelectron spectroscopy
  • the crosslinking agent (c) in the present invention is a component that can react with the acrylic polymer (a) to form a crosslinked body (three-dimensional crosslinked body) of the acrylic polymer (a).
  • a crosslinked body three-dimensional crosslinked body
  • the acrylic polymer (a) By adjusting the acrylic polymer (a) to a crosslinked product, adjustment of the initial adhesive strength of the adhesive layer, ease of cutting of the tape (easiness of cutting the adhesive layer on the cut surface), pressure deformation, etc. are adjusted. Furthermore, thermal decomposition of the main chain of the acrylic polymer (a) can be suppressed.
  • an isocyanate-based or epoxy-based crosslinking agent which is a general crosslinking agent for an acrylic pressure-sensitive adhesive, is used.
  • thermo decomposability a crosslinking agent having high heat resistance (thermal decomposability) from the viewpoint of improving the heat resistance (thermal decomposability) of the acrylic polymer (a).
  • preferred crosslinking agents (c) include those shown below, but the present invention is not limited thereto. That is, sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, diglycerol polyglycidyl ether, glycerol polyglycidyl ether, neopentyl glycol diglycidyl ether, resorcin diglycidyl ether Examples include chemical epoxy compounds such as tetrad C and tetrad X; isocyanate compounds such as tetramethylene diisocyanate, hexamethylene diisocyanate, toluene diisocyanate triadduct of trimethylolpropane, polyisocyanate, isocyanurate type isocyanate, and the like.
  • the pressure-sensitive adhesive layer before curing becomes soft and fluid and tends to be excellent in wettability and unevenness followability to the wafer surface.
  • shape stability will worsen and there exists a possibility that a level
  • the protective film of this invention is cut, there exists a possibility that the cut of an adhesive may worsen.
  • the amount of the crosslinking agent is large, the adhesive layer before curing becomes hard, it is difficult to obtain wettability and unevenness followability to the wafer surface, and the protective film may float under vacuum heating.
  • the addition amount of the crosslinking agent (c) may be determined in consideration of the above points.
  • the proper addition amount of the crosslinking agent is preferably increased because the tendency to become a soft adhesive is promoted when there are many bifunctional or higher acrylic oligomers added to the composition of the present invention.
  • the addition amount of the crosslinking agent (c) is preferably 0.1 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the total amount of monomers constituting the acrylic polymer (a). 2 parts by mass or more and 10 parts by mass or less are more preferable.
  • the composition for obtaining the thermosetting adhesive layer in the present invention further contains a bifunctional or higher functional acrylic oligomer (d).
  • the bifunctional or higher-functional acrylic oligomer (d) is an acrylic oligomer having two or more radical-reactive double bonds, and reacts with radicals generated by the specific thermal radical generator (b). It is a component that contributes to curing.
  • the above-mentioned acrylic polymer (a) does not have a radical reactive double bond in the side chain, it becomes essential as a component for thermosetting the adhesive layer.
  • the pressure-sensitive adhesive layer after heat curing is hard and brittle, the pressure-sensitive adhesive layer may break while it is biting into the irregularities on the wafer surface, and a part of the pressure-sensitive adhesive layer may remain on the wafer surface (also referred to as residue). For this reason, it is good to adjust the addition amount, the number of functional groups, etc. of bifunctional or more acrylic oligomer (d) so that the elongation at the time of the tensile fracture of the adhesion layer after thermosetting may become large. If a large number of functional groups having a large molecular weight is added, it may be hard and brittle.
  • the bifunctional or higher acrylic oligomer (d) is preferably hexafunctional or lower, more preferably trifunctional or higher and pentafunctional or lower. Since the protective film of the present invention requires heat resistance, it is preferable to select a bifunctional or higher acrylic oligomer (d) having a structure with high heat resistance (not easily thermally decomposed). From the viewpoint of heat resistance, those having an ester bond are preferable to those having a urethane bond.
  • the molecular weight of the acrylic oligomer (d) is preferably from 200 to 10,000, more preferably from 300 to 5,000, from the viewpoint of cured properties.
  • bifunctional or higher acrylic oligomer (d) include commercially available urethane acrylate, epoxy acrylate, polyester acrylate, polyether acrylate, pentaerythritol polyacrylate, dipentaerythritol polyacrylate, ethoxylated isocyanuric acid triacrylate, tri Examples include methylolpropane triacrylate and ditrimethylolpropane tetraacrylate.
  • the bifunctional or higher functional acrylic oligomer (d) may be added in the case where the acrylic polymer (a) has a radical reactive double bond in the side chain.
  • the acrylic oligomer (d) functions as a low molecular weight component, and the unevenness followability and wettability of the pressure-sensitive adhesive layer before thermosetting to the wafer surface are improved.
  • the cured adhesive layer becomes hard and brittle, and the adhesive layer described above may break.
  • the addition amount of the bifunctional or higher-functional acrylic oligomer (d) is 0 to 100 parts by mass, more preferably 0 to 50 parts by mass with respect to 100 parts by mass of the acrylic polymer (a). Less than parts by mass is appropriate.
  • the acrylic polymer (a) does not have a radical-reactive double bond in the side chain, it is essential as a component for thermally curing the adhesive layer, but a bifunctional or higher-functional acrylic oligomer (d ) Is insufficient, the thermosetting of the adhesive layer is insufficient, and a part of the adhesive layer may remain (cohesive failure) on the wafer surface.
  • the adhesive layer may break.
  • the amount of addition when the bifunctional or higher functional acrylic oligomer (d) is essential is 1 to 100 parts by mass, more preferably 100 parts by mass with respect to 100 parts by mass of the acrylic polymer (a). 20 mass parts or more and 50 mass parts or less are suitable.
  • the thickness of the pressure-sensitive adhesive layer obtained from the composition containing each component as described above is preferably formed to a thickness that can sufficiently follow the irregularities on the wafer surface.
  • the thickness of the adhesive layer is suitably 10 ⁇ m or more and 100 ⁇ m or less, more preferably 20 ⁇ m or more and 50 ⁇ m or less.
  • the polyimide base material in the present invention is selected from the following points. That is, when the base material is subjected to vacuum heating, if the base material is softened, it is not preferable because the base material is fixed to the contacting member. Moreover, it is preferable that a high elastic modulus can be maintained even at high temperatures.
  • the semiconductor wafer (silicon wafer) to which the protective film of the present invention is attached is processed to be as thin as 150 ⁇ m or less, and in some cases, 100 ⁇ m or less. When such a thin semiconductor wafer and a protective film are applied and then heated, if the linear expansion coefficient of the base material is greatly deviated from the thermal expansion coefficient of silicon of the semiconductor wafer, the semiconductor wafer is warped. .
  • a drying process for reducing the moisture contained in the protective film is performed before the process performed under vacuum heating.
  • a drying process for reducing the moisture contained in the protective film is performed.
  • the adhesive strength between the pressure-sensitive adhesive layer and the polyimide base material is obtained by subjecting the polyimide base material to a surface treatment (such as a known discharge treatment (corona, plasma) or a coupling agent treatment) or an adhesive layer. Is preferably increased.
  • the thickness of the polyimide base material is preferably 25 ⁇ m or more and 100 ⁇ m or less, and more preferably 38 ⁇ m or more and 50 ⁇ m or less. If the polyimide base material is too thin, wrinkles may be easily formed at the time of sticking. On the other hand, if it is too thick, the water vapor permeability may be deteriorated or the followability to the irregularities on the surface of the semiconductor wafer may be deteriorated. .
  • a commercially available polyimide substrate may be used as the polyimide substrate.
  • Kapton registered trademark of Toray DuPont
  • Apical registered trademark of Kaneka
  • Upilex registered trademark of Ube Industries, etc. have been commercialized and can be used. .
  • the protective film is produced as follows. First, each component which comprises the composition used in order to obtain an adhesion layer is melt
  • a protective film of the laminate may be peeled off before being attached to the semiconductor wafer.
  • the temperature and the residence time in the drying furnace in consideration of sufficiently removing the volatile component such as a solvent so that the protective film can be prevented from floating under vacuum heating.
  • the temperature in the drying step is preferably 60 ° C. or higher and 130 ° C. or lower, and the residence time is preferably 1 minute or longer and 10 minutes or shorter.
  • the protective film of the present invention is preferably used as a protective film in a method for producing a semiconductor device including the following steps (1) to (4).
  • the protective film is attached. Heating step of heating the semiconductor wafer at a temperature of 120 ° C. or higher and 180 ° C.
  • step (1) is described later in (A) a sticking step
  • step (2) is described in (C) a heating step
  • step (3) is described in (D) static.
  • step (4) corresponds to the (E) processing step under vacuum heating described later. The details of each step are the same as the corresponding (A) sticking step, (C) heating step, (D) standing step, and (E) processing step under vacuum heating, and thus are omitted here.
  • a method for manufacturing a semiconductor device of the present invention includes: (A) An attaching step of attaching the protective film of the present invention to the circuit forming surface of the semiconductor wafer so that the thermosetting adhesive layer is in contact with the circuit forming surface; (B) a grinding step of grinding a non-circuit-formed surface of the semiconductor wafer; (C) a heating step of heating the semiconductor wafer to which the protective film is attached and the non-circuit-formed surface is ground at a temperature of 120 ° C. or higher and 180 ° C.
  • the sticking step in the present invention the sticking is performed so that the thermosetting adhesive layer in the protective film of the present invention is in contact with the circuit forming surface of the semiconductor wafer.
  • This (A) sticking process is performed before or after the (B) grinding process.
  • the semiconductor wafer to which the protective film of the present invention is stuck is applied to the (B) grinding step as it is.
  • a sticking process is performed after (B) a grinding process, it sticks so that the adhesion layer in a well-known protective film may contact
  • the process of peeling a well-known protective film from a semiconductor wafer is performed. Since the number of steps is small and there is no need to replace the protective film, it is preferable to perform the (A) pasting step before the (B) grinding step.
  • a known tape applicator can be applied to the protective film of the present invention applied to the semiconductor wafer.
  • a vacuum applicator In order to apply air to the irregularities of the circuit on the wafer surface without applying air, it is preferable to use a vacuum applicator. It is not preferable to bite air because (E) the protective film floats in the processing step performed under vacuum heating.
  • the non-circuit-formed surface (wafer back surface) of the semiconductor wafer is ground.
  • a semiconductor wafer to which the protective film of the present invention or the conventional protective film is attached is fixed to a chuck table of a grinding machine via a polyimide base material, and a circuit is not formed on the semiconductor wafer. Grind the surface (wafer back). After the grinding is finished, when the conventional protective film is stuck on the semiconductor wafer, the protective film is peeled off.
  • the semiconductor wafer with the protective film attached may be subjected to an etching process step using a chemical solution such as chemical etching or polishing of the back surface of the wafer.
  • the semiconductor wafer to which the protective film of the present invention is attached is preheated to remove moisture in the protective film.
  • the protective film of the present invention is composed of an acrylic pressure-sensitive adhesive and a polyimide base material, both of which are materials having a high moisture absorption rate. Since the grinding process and the etching process are processes using water, the protective film of the present invention is in a moisture-absorbing state. When the moisture-absorbing protective film is heated in the heating step (C), floating may occur due to rapid expansion of moisture absorbed.
  • an oven or the like and preheat and dry the semiconductor wafer to which the protective film of the present invention is attached at 60 ° C. or higher and 100 ° C. or lower for several minutes to several tens of minutes.
  • the semiconductor wafer to which the protective film of the present invention is attached and the non-circuit-formed surface is ground is heated at a temperature of 120 ° C. or higher and 180 ° C. or lower.
  • This step may be carried out under reduced pressure or under increased pressure, but if it is carried out under reduced pressure, floating may occur due to the generated gas accompanying decomposition of the peroxide. It is preferable to carry out at atmospheric pressure from the viewpoint that a general-purpose oven can be used.
  • the adhesive layer of the protective film of the present invention is thermally cured.
  • the heating conditions in the (C) heating step may be set according to the 1-minute half-life temperature of the used specific thermal radical generator (b).
  • the specific thermal radical generator (b ) Preferably within ⁇ 30 ° C. (more preferably within ⁇ 20 ° C.).
  • the heating step is performed at a temperature of 120 ° C. or higher and 180 ° C. or lower (preferably 130 ° C. or higher and 170 ° C. or lower) at atmospheric pressure, and several minutes or longer and 1 hour or shorter (preferably 1). It is preferable to carry out heating for a period of 1 minute to 1 hour, more preferably 3 minutes to 30 minutes, still more preferably 5 minutes to 30 minutes, particularly preferably 10 minutes to 30 minutes.
  • a vacuum deposition apparatus is applied to metal deposition
  • a sputtering apparatus is applied to metal sputtering
  • an ion implantation apparatus is applied to ion implantation.
  • Vacuum equipment In these vacuum apparatuses, generally, a semiconductor wafer is allowed to stand in a preliminary exhaust chamber, and after reaching a certain degree of vacuum (for example, 1 Pa or less), the semiconductor wafer is transferred to this apparatus. The standing in the preliminary exhaust chamber is the above-described (D) standing step.
  • metal vapor deposition, metal sputtering, or ion implantation is performed under vacuum, and the semiconductor wafer in the apparatus at that time is heated to 200 ° C. or higher.
  • the upper limit of the heating in the processing step (E) under vacuum heating is determined by the type of the processing, the heating / cooling mechanism of the apparatus, etc., specifically, it is about 300 ° C.
  • (E) the protective film of the present invention is peeled from the semiconductor wafer after the treatment process under vacuum heating.
  • an automatic peeling machine Takatori Co., Ltd., model: ATRM-2000B, ATRM-2100, Teikoku Seiki Co., Ltd., model: STP series, Nitto Seiki Co., Ltd., model: HR-8500II Etc.
  • an adhesive tape called a peeling tape used when peeling the protective film of the present invention from the wafer surface by the automatic peeling machine for example, Sumitomo 3M Co., Ltd., Highland Mark Filament Tape No. 897 or the like can be used.
  • the temperature at which the protective film of the present invention is peeled off from the wafer surface is usually performed at room temperature of about 25 ° C. However, when the above-described automatic peeling machine has a function of heating the wafer, the semiconductor wafer The protective film may be peeled off while the temperature is raised to a predetermined temperature (usually about 40 ° C. to 90 ° C.).
  • the wafer surface after peeling off the protective film of the present invention is cleaned as necessary.
  • the cleaning method include wet cleaning such as water cleaning and solvent cleaning, and dry cleaning such as plasma cleaning.
  • wet cleaning ultrasonic cleaning may be used in combination. These cleaning methods are appropriately selected depending on the contamination state of the wafer surface.
  • the semiconductor device manufacturing method of the present invention preferably further includes the following steps.
  • the polyimide base material is hard, and when the thickness of the adhesive layer is thin, the unevenness on the wafer surface may not be absorbed. In this case, the back surface of the convex portion may be excessively ground during grinding in the (B) grinding step. From the standpoint of preventing this, a method of applying a known semiconductor wafer grinding film to the surface of the polyimide base material (non-adhesive surface of the adhesive layer) in the protective film of the present invention is employed.
  • the step of attaching the semiconductor wafer grinding film to the surface of the polyimide base material of the protective film applied to the semiconductor wafer ((i) ))
  • a method of applying a semiconductor wafer grinding film in advance to the surface of the polyimide base material of the protective film (B) the step of attaching the semiconductor wafer grinding film to the surface of the polyimide base material of the protective film applied to the semiconductor wafer ((i) ))
  • a method of applying a semiconductor wafer grinding film in advance to the surface of the polyimide base material of the protective film preferably includes a soft / stress relaxation layer that absorbs irregularities on the wafer surface.
  • the semiconductor wafer grinding film is preferably peeled off from the protective film of the present invention after the (B) grinding step and before the (C) heating step ((ii) step).
  • the grinding step is a step of grinding the inner peripheral portion while leaving the outer peripheral portion of the circuit non-formed surface in the semiconductor wafer.
  • the (B) grinding step it is preferable to use a so-called Tyco process, in which the outer peripheral edge of the semiconductor wafer is left thick and the strength is increased while the center is ground to a predetermined thickness.
  • the polyimide base material in the protective film of the present invention does not cause thermal expansion and does not completely match the thermal expansion coefficient with the silicon wafer.
  • the above-described Tyco process is used in combination with the protective film of the present invention applied.
  • Semiconductor wafers to which the method for manufacturing a semiconductor device of the present invention can be applied are not limited to silicon wafers, but include semiconductor wafers such as gallium nitride, germanium, gallium-arsenic, gallium-phosphorus, and gallium-arsenic-aluminum.
  • a compounding quantity is a mass part with respect to 100 mass parts of monomers in an acrylic polymer, and is a mass ratio of solid content.
  • Polymers 1 and 2 oligomers 1 and 2, peroxides 1 to 5, and crosslinking agent 1 abbreviated in Table 2 are as follows.
  • Polymer 1 82 parts of ethyl acrylate, 10 parts of methyl methacrylate, 8 parts of hydroxybutyl acrylate and 0.5 parts by weight of benzoyl peroxide as a polymerization initiator are mixed, 65 parts by weight of toluene, 50 parts by weight of ethyl acetate was added dropwise at 80 ° C. over 5 hours while stirring in a nitrogen-substituted flask containing, and the reaction was further stirred for 5 hours to obtain an acrylate copolymer solution. This was designated as Polymer 1.
  • Polymer 2 48 parts by mass of ethyl acrylate, 27 parts by mass of 2-ethylhexyl acrylate, 20 parts by mass of methyl acrylate, 5 parts by mass of glycidyl methacrylate, and 0.5 parts by mass of benzoyl peroxide as a polymerization initiator
  • the mixture was added dropwise to a nitrogen-substituted flask containing 65 parts by mass of toluene and 50 parts by mass of ethyl acetate with stirring at 80 ° C. over 5 hours, and further stirred for 5 hours to be reacted.
  • Oligomer 1 AD-TMP (manufactured by Shin-Nakamura Chemical, ditrimethylolpropane tetraacrylate)
  • Oligomer 2 Allonics M-402 (Toagosei, dipentaerythritol pentaacrylate and hexaacrylate)
  • Peroxide 1 Pertetra A (manufactured by NOF, 2,2-Di (4,4-di- (t-butylperoxy) cyclohexyl) propane, molecular weight 561, 1 minute half-life temperature 154 ° C.)
  • Peroxide 2 Niper BMT (manufactured by NOF, 1 minute half-life temperature 131 ° C)
  • Peroxide 3 Parroyl TCP (manufactured by NOF, molecular weight 399, half-life temperature 92 ° C.
  • Peroxide 4 Perbutyl C (manufactured by NOF, t-Butyl cumyl peroxide, molecular weight 208, 1 minute half-life temperature 173 ° C.)
  • Peroxide 5 Parkmill P (manufactured by NOF, molecular weight 194, 1 minute half-life temperature 233 ° C.)
  • Crosslinking agent 1 Olester P49-75S (Mitsui Chemicals)
  • the protective films of Examples 1 to 4 were prepared from the acrylic polymer (a), the specific thermal radical generator (b), the crosslinking agent (c), and the bifunctional or higher acrylic in the present invention. Because it has a pressure-sensitive adhesive layer obtained from a coating solution containing an oligomer (d), the protective film does not float even when subjected to vacuum heating after thermosetting, and no residue remains I understand.
  • Example A After the protective film of Example 1 was attached to the mirror surface of a 6-inch silicon wafer, this was heated in an oven at 80 ° C. for 10 minutes (preliminary heating), and then heated in an oven at 150 ° C. for 15 minutes. Then, the adhesive layer was thermally cured. Subsequently, this was put into a vacuum oven and placed under vacuum, and then heated at 250 ° C. for 30 minutes. Note that the preheating and the heating during the thermosetting of the adhesive layer were performed under atmospheric pressure.
  • Examples B to D, Comparative Examples a to f, and Reference Example Except that the protective film used in Example A was replaced with the protective film described in Table 3 below, and the heating described in Table 3 was performed. Same as Example A. When vacuum heating was performed in Examples A to D, Comparative Examples a to f, and Reference Examples, the presence or absence of occurrence of floating of the protective film was visually confirmed in the oven. Moreover, after returning to room temperature after vacuum heating, the protective film was peeled from the silicon wafer, and it was visually confirmed whether or not the adhesive layer remained on the silicon wafer. The results are shown in Table 3.
  • thermosetting of the adhesive layer is insufficient.
  • Comparative Example d using the protective film of Comparative Example 4 after preheating, without performing the thermosetting of the adhesive layer and leaving it under vacuum and at 200 ° C. or higher, did not cause a residue, The protective film was lifted. This is because a coating solution containing a large amount of a crosslinking agent is used, so that it is a hard adhesive layer, has low wettability with respect to the silicon wafer, and was unable to maintain adhesion to the silicon wafer during vacuum heating. Presumed to be.
  • Comparative Example e in which the protective film of Comparative Example 5 was used, and after the preliminary heating, the adhesive layer was not thermally cured, and was left in a vacuum at 200 ° C. or higher, the protective film did not float. However, it was found that there was a residue. This is because it uses a coating solution with a small amount of crosslinking agent added, it is a soft adhesive layer, excellent wettability to the silicon wafer, and was able to maintain adhesion to the silicon wafer even under vacuum heating, It is presumed that the adhesiveness has increased due to the high temperature, and the residue remains.
  • Example E The protective film of Example 1 was affixed to the mirror surface of an 8-inch silicon wafer (mirror) ((A) affixing process). Subsequently, the back surface of the wafer was ground to a thickness of 100 ⁇ m using a disco back grinder ((B) grinding step). After grinding, the wafer was not cracked and warpage was 1 mm or less. Next, the wafer was dried in an oven at 80 ° C. for 10 minutes (preliminary heating), and then further heated in an oven at 150 ° C. for 15 minutes to cure the adhesive layer ((C) heating step). Note that the preheating and the heating during the thermosetting of the adhesive layer were performed under atmospheric pressure.
  • the warpage of the wafer was about 2 mm, which was the amount of warpage that could be handled by the wafer transfer device. Subsequently, the wafer was put into a vacuum oven and placed under vacuum, and then heated at 250 ° C. for 30 minutes. No floating occurred in the vacuum oven. Thereafter, when the protective film of Example 1 was peeled off from the wafer returned to the atmospheric pressure and room temperature environment, no residue was observed on the wafer surface.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • General Physics & Mathematics (AREA)
  • Manufacturing & Machinery (AREA)
  • Computer Hardware Design (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Power Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • Mechanical Treatment Of Semiconductor (AREA)
  • Adhesives Or Adhesive Processes (AREA)
  • Adhesive Tapes (AREA)

Abstract

A protective film that is stuck to a circuit formation surface of a semiconductor wafer, that has a polyimide substrate, and that has a heat-curable adhesive layer that is provided on one surface of the polyimide substrate and that is obtained from a composition that includes an acrylic polymer (a), a thermal radical generator (b) that has a one-minute half-life temperature of 140-200 °C, and a crosslinking agent (c).

Description

保護フィルム、及び、該保護フィルムを用いる半導体装置の製造方法Protective film and method for manufacturing semiconductor device using the protective film
　本発明は、保護フィルム、及び、該保護フィルムを用いる半導体装置の製造方法に関する。
　詳しくは、ディスクリートデバイスやＩＧＢＴ素子などの半導体装置の製造工程に用いられ、半導体ウェハの回路形成面を保護する保護フィルムと該保護フィルムを用いた半導体装置の製造方法に関する。 The present invention relates to a protective film and a method for manufacturing a semiconductor device using the protective film.
Specifically, the present invention relates to a protective film that is used in a manufacturing process of a semiconductor device such as a discrete device or an IGBT element and protects a circuit forming surface of a semiconductor wafer, and a method of manufacturing a semiconductor device using the protective film.
　ディスクリートデバイスやＩＧＢＴ素子の製造の際には、従来、半導体ウェハの回路非形成面（以下、適宜「ウェハ裏面」という）を研削する工程、ウェハ裏面の加工変質層を薬液等でエッチングする工程、ウェハ裏面に金属電極を形成する工程、また、ＩＧＢＴ素子の場合は更に、ウェハ裏面にイオン注入する工程、注入したドーパントを活性化するアニール工程など、ウェハ裏面側に種々の加工が施される。
　中でも、ウェハ裏面を研削して半導体ウェハを薄層化する工程では、半導体ウェハの破損、汚染を防止するために、半導体ウェハの回路形成面（以下、適宜「ウェハ表面」という）に、粘着層を備えた保護フィルムが貼付される。 In the manufacture of discrete devices and IGBT elements, conventionally, a step of grinding a circuit non-formed surface of a semiconductor wafer (hereinafter referred to as “wafer backside” as appropriate), a step of etching a work-affected layer on the backside of a wafer with a chemical solution, Various processes are performed on the back side of the wafer, such as a step of forming a metal electrode on the back side of the wafer, and in the case of an IGBT element, a step of ion implantation into the back side of the wafer and an annealing step of activating the implanted dopant.
In particular, in the step of thinning the semiconductor wafer by grinding the back surface of the wafer, an adhesive layer is applied to the circuit forming surface of the semiconductor wafer (hereinafter referred to as “wafer surface” as appropriate) in order to prevent damage and contamination of the semiconductor wafer. A protective film with is attached.
　このような保護フィルムとしては、以下のようなものが挙げられる。
　例えば、特開２０１１－２１６７３５号公報及び特開２０１１－２１３９１９号公報には、「ポリエステル樹脂で構成されている基材樹脂フィルム上に放射線硬化性の粘着剤層を備えたウェハ加工用粘着テープ」が開示されている。
　また、特開２０１０－２８７８１９号公報には、「基材フィルム上に、粘着成分と硬化成分とを含む中間樹脂層組成物を硬化して形成された中間樹脂層と放射線硬化性の粘着剤層とがこの順に積層された半導体ウェハ加工用粘着テープ」が開示されている。
　また、特開２０１１－２４９６０８号公報には、「ポリエステル樹脂を含有した基材樹脂フィルム上に、放射線硬化性の樹脂組成物により構成されている粘着剤層を備えた半導体ウェハ表面保護用粘着テープ」が開示されている。 Examples of such a protective film include the following.
For example, in JP 2011-216735 A and JP 2011-213919 A, “adhesive tape for wafer processing provided with a radiation-curable adhesive layer on a base resin film made of polyester resin” is disclosed. Is disclosed.
Japanese Patent Application Laid-Open No. 2010-287819 discloses that “an intermediate resin layer formed by curing an intermediate resin layer composition containing an adhesive component and a curing component on a base film and a radiation curable adhesive layer” A semiconductor wafer processing pressure-sensitive adhesive tape in which and are laminated in this order is disclosed.
Japanese Patent Application Laid-Open No. 2011-249608 discloses that “a pressure-sensitive adhesive tape for protecting a semiconductor wafer surface comprising a pressure-sensitive adhesive layer made of a radiation-curable resin composition on a base resin film containing a polyester resin”. Is disclosed.
　上記のものの他、粘着層を備えたフィルムとしては、減圧加熱工程を有する半導体の加工時において半導体に貼付してこれを保護するためのものとして、例えば、特開２０１２－１０９５８５号公報には「基材の少なくとも一方の面に、光硬化型粘着剤、特定の粒子径のシリカ微粒子、及び気体発生剤を含む粘着剤層を備えた半導体加工用テープ」が開示されている。 In addition to the above, the film provided with the adhesive layer is a film for sticking to a semiconductor to protect it during the processing of the semiconductor having a reduced pressure heating process. For example, Japanese Patent Application Laid-Open No. 2012-109585 discloses “ A semiconductor processing tape is disclosed which includes a pressure-sensitive adhesive layer containing a photocurable pressure-sensitive adhesive, silica fine particles having a specific particle diameter, and a gas generating agent on at least one surface of a substrate.
　更に、粘着層を備えたフィルムとしては、加熱することで粘着力を低下させる半導体ウェハ固定用シートとして、例えば、特開平１０－０２５４５６号公報には、「シート状の支持体と、該支持体上に積層された感圧性粘着剤で主要部が形成される半導体ウェハ固定用シートにおいて、該粘着剤の主成分が、ベースポリマー１００質量部、加熱硬化性化合物１０～９００質量部及び加熱重合開始剤０．１～１０質量部で形成されていることを特徴とする半導体ウェハ固定用シート」が開示されている。 Furthermore, as a film provided with an adhesive layer, as a sheet for fixing a semiconductor wafer whose adhesive strength is reduced by heating, for example, in JP-A-10-025456, “sheet-like support and support In the semiconductor wafer fixing sheet, the main part of which is formed of a pressure-sensitive adhesive laminated on top thereof, the main component of the adhesive is 100 parts by weight of the base polymer, 10 to 900 parts by weight of the thermosetting compound, and heat polymerization is started. A semiconductor wafer fixing sheet characterized by being formed with 0.1 to 10 parts by mass of an agent is disclosed.
　また、装飾用シート等に適用される粘着シートとして、例えば、特開平８－３０２３０１号公報には、「１×１０８ｃｃ・ｃｍ／ｃｍ２・ｓｅｃ・ｃｍＨｇ以上の酸素透過係数を有する厚み５００μｍ以下のフィルム状基材に、酸素が存在すると硬化せず若しくは硬化が遅延されるが加熱により硬化する硬化性粘着剤層を形成してなる加熱剥離性粘着シート。」が開示されており、かかる粘着シートの硬化性粘着剤層が粘着性ゴム系樹脂（Ａ）１００質量部を基準として、エチレン性不飽和基含有化合物（Ｂ）を５０～１５０質量部、有機過酸化物（Ｃ）を０．１～１５質量部、架橋剤（Ｄ）を０．０１～５．００質量部及び重合禁止剤（Ｅ）を０．００１～１．０質量部配合してなることも開示されている。
いる。
　この粘着シートは、加熱することで容易に剥離可能になるといった特徴を有する。 Further, as an adhesive sheet applied to a decorative sheet or the like, for example, JP-A-8-302301 discloses a thickness of 500 μm having an oxygen transmission coefficient of “1 × 10 8 cc · cm / cm 2 · sec · cmHg or more. A heat-peelable pressure-sensitive adhesive sheet formed by forming a curable pressure-sensitive adhesive layer that does not cure or is delayed in the presence of oxygen in the following film-like substrate but is cured by heating is disclosed. The curable pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet is based on 100 parts by weight of the pressure-sensitive rubber resin (A), 50 to 150 parts by weight of the ethylenically unsaturated group-containing compound (B), and 0% of the organic peroxide (C). It is also disclosed that 1 to 15 parts by mass, 0.01 to 5.00 parts by mass of a crosslinking agent (D) and 0.001 to 1.0 parts by mass of a polymerization inhibitor (E) are blended.
Yes.
This pressure-sensitive adhesive sheet has a feature that it can be easily peeled off by heating.
　前記したウェハ裏面側に対して施される種々の加工には、半導体ウェハが真空下で加熱される工程を含んでいる。
　特に、金属蒸着、金属スパッタ、及びイオン注入といった加工を行う工程では、半導体ウェハは真空装置内において真空下で２００℃以上の加熱がなされる。
　前述したような各特許文献に記載の粘着層を備えたフィルムが貼付された半導体ウェハを、真空下で２００℃以上に加熱すると、フィルムに浮きが発生したり、半導体ウェハからの剥離が困難となるほど粘着力が上昇してしまうことがある。フィルムに浮きが発生すると、搬送が困難となったりする。
　つまり、従来の粘着層を備えたフィルムは、真空下で２００℃以上の加熱がなされる工程には適用できないのが現状である。
　ここで、本明細書では、真空下で２００℃以上の加熱を適宜「真空加熱」と称する。 The various processes performed on the wafer back side described above include a step of heating the semiconductor wafer under vacuum.
In particular, in a process of performing processes such as metal vapor deposition, metal sputtering, and ion implantation, the semiconductor wafer is heated to 200 ° C. or higher under vacuum in a vacuum apparatus.
When a semiconductor wafer to which a film provided with the adhesive layer described in each patent document as described above is attached is heated to 200 ° C. or higher under vacuum, the film may be lifted or peeled off from the semiconductor wafer. In some cases, the adhesive strength may increase. If the film floats, it may be difficult to convey.
That is, the present situation is that a film having a conventional adhesive layer cannot be applied to a process in which heating at 200 ° C. or higher is performed under vacuum.
Here, in this specification, heating at 200 ° C. or higher under vacuum is appropriately referred to as “vacuum heating”.
　以上のような状況下、本発明の課題は、半導体ウェハの回路形成面に貼付し、熱硬化性粘着層を熱硬化させた後に、半導体ウェハに貼付されたまま真空加熱下で行われる工程を含む半導体装置の製造方法に適用したとき、半導体ウェハの回路形成面を保護しつつ、浮きの発生を抑制し、且つ、半導体ウェハから剥離する際の剥離性に優れる保護フィルムを提供することにある。
　また、本発明の他の課題は、上記保護フィルムを用いた、真空加熱下で行われる工程を含む半導体装置の製造方法を提供することにある。 Under the circumstances as described above, an object of the present invention is to apply a process that is performed under vacuum heating while being adhered to a semiconductor wafer after being adhered to a circuit forming surface of a semiconductor wafer and thermosetting the thermosetting adhesive layer. An object of the present invention is to provide a protective film that, when applied to a method for manufacturing a semiconductor device, suppresses the occurrence of floating while protecting the circuit forming surface of the semiconductor wafer and is excellent in releasability when peeling from the semiconductor wafer. .
Moreover, the other subject of this invention is providing the manufacturing method of the semiconductor device including the process performed under vacuum heating using the said protective film.
　前記課題を解決するための手段は、以下の通りである。 The means for solving the above-mentioned problems are as follows.
＜１＞　ポリイミド基材と、
　前記ポリイミド基材の片表面に設けられ、アクリル系重合体（ａ）、１分間半減期温度が１４０℃以上２００℃以下である熱ラジカル発生剤（ｂ）、及び架橋剤（ｃ）を含む組成物から得られた熱硬化性粘着層と、
　を有し、半導体ウェハの回路形成面に貼付される保護フィルム。 <1> a polyimide base material;
A composition comprising an acrylic polymer (a), a thermal radical generator (b) having a half-life temperature of 140 ° C. or more and 200 ° C. or less, and a crosslinking agent (c) provided on one surface of the polyimide substrate. A thermosetting adhesive layer obtained from the product,
A protective film that is attached to a circuit forming surface of a semiconductor wafer.
＜２＞　前記熱ラジカル発生剤（ｂ）の分子量が２００以上１０００以下である＜１＞に記載の保護フィルム。
＜３＞　前記組成物が２官能以上のアクリル系オリゴマー（ｄ）を更に含む＜１＞又は＜２＞に記載の保護フィルム。
＜４＞　前記アクリル系重合体（ａ）が側鎖にラジカル反応性の二重結合を有する重合体である＜１＞～＜３＞のいずれか１に記載の保護フィルム。
＜５＞　（１）半導体ウェハの回路形成面に、熱硬化性粘着層を有する保護フィルムを当該回路形成面と当該熱硬化性粘着層が接するように貼付する貼付工程と、
　（２）前記保護フィルムが貼付された前記半導体ウェハを１２０℃以上１８０℃以下の温度で加熱する加熱工程と、
　（３）（２）の加熱工程後、前記保護フィルムが貼付された前記半導体ウェハを真空下に静置する静置工程と、
　（４）（３）の静置工程後、真空且つ２００℃以上の条件下で、前記半導体ウェハにおける回路非形成面に対し、金属蒸着、金属スパッタ、及びイオン注入のいずれか１つの処理を施す処理工程と、
　を含む半導体装置の製造方法における前記保護フィルムとして用いられる、＜１＞～＜４＞のいずれか１に記載の保護フィルム。 <2> The protective film according to <1>, wherein the thermal radical generator (b) has a molecular weight of 200 or more and 1000 or less.
<3> The protective film according to <1> or <2>, wherein the composition further contains a bifunctional or higher functional acrylic oligomer (d).
<4> The protective film according to any one of <1> to <3>, wherein the acrylic polymer (a) is a polymer having a radical-reactive double bond in a side chain.
<5> (1) An attaching step of attaching a protective film having a thermosetting adhesive layer to a circuit forming surface of a semiconductor wafer so that the circuit forming surface and the thermosetting adhesive layer are in contact with each other;
(2) a heating step of heating the semiconductor wafer to which the protective film is attached at a temperature of 120 ° C. or higher and 180 ° C. or lower;
(3) After the heating step of (2), a standing step of standing the semiconductor wafer to which the protective film is attached under vacuum,
(4) After the stationary step of (3), any one of metal vapor deposition, metal sputtering, and ion implantation is performed on the non-circuit-formed surface of the semiconductor wafer under vacuum and at 200 ° C. or higher. Processing steps;
The protective film according to any one of <1> to <4>, which is used as the protective film in a method for producing a semiconductor device comprising:
＜６＞　（Ａ）半導体ウェハの回路形成面に、＜１＞～＜５＞のいずれか１項に記載の保護フィルムを、当該回路形成面に前記熱硬化性粘着層が接するように貼付する貼付工程と、
　（Ｂ）前記半導体ウェハにおける回路非形成面を研削する研削工程と、
　（Ｃ）前記保護フィルムが貼付され、回路非形成面が研削された前記半導体ウェハを１２０℃以上１８０℃以下の温度で加熱する加熱工程と、
　（Ｄ）（Ｃ）の加熱工程後、前記保護フィルムが貼付された前記半導体ウェハを真空下に静置する静置工程と、
　（Ｅ）（Ｄ）の静置工程後、真空且つ２００℃以上の条件下で、前記保護フィルムが貼付された前記半導体ウェハにおける回路非形成面に対し、金属蒸着、金属スパッタ、及びイオン注入のいずれか１つの処理を施す処理工程と、
　（Ｆ）前記保護フィルムを前記半導体ウェハから剥離する剥離工程と、
　を含む、半導体装置の製造方法。 <6> (A) The protective film according to any one of <1> to <5> is attached to a circuit forming surface of a semiconductor wafer so that the thermosetting adhesive layer is in contact with the circuit forming surface. Pasting process,
(B) a grinding step of grinding a non-circuit-formed surface of the semiconductor wafer;
(C) a heating step of heating the semiconductor wafer to which the protective film is attached and the non-circuit-formed surface is ground at a temperature of 120 ° C. or higher and 180 ° C. or lower;
(D) after the heating step of (C), a standing step of standing the semiconductor wafer to which the protective film is stuck under vacuum;
(E) After the standing step of (D), under vacuum and at a temperature of 200 ° C. or higher, metal deposition, metal sputtering, and ion implantation are performed on the non-circuit-formed surface of the semiconductor wafer to which the protective film is attached. A processing step of applying any one of the processing;
(F) a peeling step of peeling the protective film from the semiconductor wafer;
A method for manufacturing a semiconductor device, comprising:
＜７＞　前記（Ａ）の貼付工程の後で、且つ、前記（Ｂ）の研削工程の前に、
　（ｉ）前記保護フィルムのポリイミド基材の表面に、半導体ウェハ研削用フィルムを貼付する工程を含む＜６＞に記載の半導体装置の製造方法。
＜８＞　前記（Ａ）の貼付工程に用いられる前記保護フィルムが、該保護フィルムのポリイミド基材の表面に半導体ウェハ研削用フィルムを貼付してなる、＜６＞に記載の半導体装置の製造方法。
＜９＞　前記（Ｂ）の研削工程の後で、且つ、前記（Ｃ）の加熱工程の前に、
　（ii）前記半導体ウェハ研削用フィルムを前記保護フィルムから剥離する工程を含む＜７＞又は＜８＞に記載の半導体装置の製造方法。
＜１０＞　前記（Ｂ）の研削工程が、前記半導体ウェハにおける回路非形成面の外周縁部を残し、内周部を研削する工程である＜６＞～＜９＞のいずれか１項に記載の半導体装置の製造方法。 <7> After the pasting step (A) and before the grinding step (B),
(I) The method for producing a semiconductor device according to <6>, including a step of attaching a semiconductor wafer grinding film to the surface of the polyimide base material of the protective film.
<8> The method for producing a semiconductor device according to <6>, wherein the protective film used in the attaching step (A) is obtained by attaching a semiconductor wafer grinding film to a surface of a polyimide base material of the protective film. .
<9> After the grinding step (B) and before the heating step (C),
(Ii) The method for manufacturing a semiconductor device according to <7> or <8>, including a step of peeling the semiconductor wafer grinding film from the protective film.
<10> The method according to any one of <6> to <9>, wherein the grinding step (B) is a step of grinding an inner peripheral portion while leaving an outer peripheral portion of a circuit non-formed surface in the semiconductor wafer. Semiconductor device manufacturing method.
　本発明によれば、半導体ウェハの回路形成面に貼付し、熱硬化性粘着層を熱硬化させた後に、半導体ウェハに貼付されたまま真空加熱下で行われる工程を含む半導体装置の製造方法に適用したときに、半導体ウェハの回路形成面を保護しつつ、浮きの発生を抑制し、且つ、半導体ウェハから剥離する際の剥離性に優れる保護フィルムを提供することができる。
　また、本発明によれば、上記保護フィルムを用いた、真空加熱下で行われる工程を含む半導体装置の製造方法を提供することができる。 According to the present invention, there is provided a method for manufacturing a semiconductor device, including a step of applying a vacuum heating while being attached to a semiconductor wafer after being attached to a circuit forming surface of a semiconductor wafer and thermosetting the thermosetting adhesive layer. When applied, it is possible to provide a protective film that suppresses the occurrence of floating while protecting the circuit forming surface of the semiconductor wafer and is excellent in releasability when peeling from the semiconductor wafer.
Moreover, according to this invention, the manufacturing method of the semiconductor device including the process performed under vacuum heating using the said protective film can be provided.
　以下、本発明について詳細に説明する。
　本明細書において、「～」を用いて表される数値範囲は、「～」の前後に記載される数値を下限値及び上限値として含む範囲を意味する。
　本発明の保護フィルムは、ポリイミド基材と、前記ポリイミド基材の片表面に設けられ、アクリル系重合体（ａ）、１分間半減期温度が１４０℃以上２００℃以下である熱ラジカル発生剤（ｂ）（以降、適宜「特定熱ラジカル発生剤（ｂ）」と称する）、及び架橋剤（ｃ）を含む組成物から得られた熱硬化性粘着層と、を有し、半導体ウェハの回路形成面に貼付される保護フィルムである。 Hereinafter, the present invention will be described in detail.
In the present specification, a numerical range expressed using “to” means a range including numerical values described before and after “to” as a lower limit value and an upper limit value.
The protective film of the present invention is a polyimide base and a thermal radical generator (a) provided on one surface of the polyimide base and having an acrylic polymer (a) and a one-minute half-life temperature of 140 ° C. or higher and 200 ° C. or lower ( b) (hereinafter referred to as “specific thermal radical generator (b)” as appropriate) and a thermosetting adhesive layer obtained from a composition containing a crosslinking agent (c), and forming a circuit on a semiconductor wafer It is a protective film affixed to the surface.
　上記のような構成を採用することにより、真空加熱下で行われる工程を含む半導体装置の製造方法に適用しても、半導体ウェハの回路形成面を保護しつつ、浮きの発生を抑制し、且つ、半導体ウェハから剥離する際の剥離性に優れる保護フィルムが得られる。
　本発明の構成を採用することによって奏される効果との関係については定かではないが、以下のように推定される。 By adopting the configuration as described above, even when applied to a method of manufacturing a semiconductor device including a process performed under vacuum heating, the occurrence of floating is suppressed while protecting the circuit forming surface of the semiconductor wafer, and A protective film having excellent releasability when peeled from a semiconductor wafer is obtained.
The relationship with the effect produced by adopting the configuration of the present invention is not clear, but is estimated as follows.
　熱硬化性粘着層中に含まれる、１分間半減期温度が１４０℃以上２００℃以下である熱ラジカル発生剤（ｂ）は、室温での保存時や、熱硬化性粘着層を形成する際の乾燥条件では分解が始まり難く、且つ、半導体ウェハからの剥離が困難となるほどの粘着力が発現するような加熱条件としなくとも分解する性質を有するものである。
　また、ポリイミド基材は、加熱による軟化が起き難く、高温でも高い弾性率を維持でき、熱膨張率が半導体ウェハに近く、更に、熱収縮率が低いといった性質を有する。
　上記のような熱ラジカル発生剤（ｂ）を用いる熱硬化性粘着層と、ポリイミド基材とを組み合わせることで、本発明の保護フィルムは、半導体ウェハの回路形成面に貼付し、熱硬化性粘着層を熱硬化させることで、高温であっても膨張し難く、且つ、半導体ウェハからの昜剥離性を有する粘着層（熱硬化後）とすることができるものと推測される。
　その結果、硬化後の粘着層の存在により、本発明の保護フィルムは、真空加熱下といった過酷な環境で行われる工程に供しても、浮きの発生を抑制し、半導体ウェハの回路形成面の保護を継続させることができ、その後、半導体ウェハから剥離する際にも優れた剥離性を示すことができる。 The thermal radical generator (b) having a one-minute half-life temperature of 140 ° C. or more and 200 ° C. or less contained in the thermosetting adhesive layer is suitable for storage at room temperature or when forming a thermosetting adhesive layer. Decomposition is difficult to start under dry conditions, and it has the property of decomposing even without heating conditions that develop adhesive strength that makes it difficult to peel from the semiconductor wafer.
In addition, the polyimide base material is unlikely to be softened by heating, can maintain a high elastic modulus even at a high temperature, has a property such that the thermal expansion coefficient is close to that of a semiconductor wafer, and the thermal contraction ratio is low.
By combining the thermosetting adhesive layer using the thermal radical generator (b) as described above and a polyimide base material, the protective film of the present invention is applied to the circuit forming surface of a semiconductor wafer, and the thermosetting adhesive By thermosetting the layer, it is estimated that it is difficult to expand even at a high temperature, and that it can be a pressure-sensitive adhesive layer (after thermosetting) having peelability from the semiconductor wafer.
As a result, due to the presence of the adhesive layer after curing, the protective film of the present invention suppresses the occurrence of floating even when subjected to a process performed in a harsh environment such as under vacuum heating, and protects the circuit forming surface of the semiconductor wafer. Can be continued, and after that, excellent peelability can also be exhibited when peeling from the semiconductor wafer.
　以下、本発明の保護フィルムを構成するポリイミド基材及び熱硬化性粘着層について説明する。 Hereinafter, the polyimide base material and the thermosetting adhesive layer constituting the protective film of the present invention will be described.
（熱硬化性粘着層）
　本発明における熱硬化性粘着層（以降、「粘着層」と略記することがある）は、アクリル系重合体（ａ）、１分間半減期温度が１４０℃以上２００℃以下である熱ラジカル発生剤（ｂ）、及び架橋剤（ｃ）を含む組成物から得られるものである。 (Thermosetting adhesive layer)
The thermosetting pressure-sensitive adhesive layer in the present invention (hereinafter sometimes abbreviated as “pressure-sensitive adhesive layer”) is an acrylic polymer (a), a one-minute half-life temperature of 140 ° C. or higher and 200 ° C. or lower. It is obtained from the composition containing (b) and a crosslinking agent (c).
－アクリル系重合体（ａ）－
　アクリル系重合体（ａ）は、粘着層における粘着剤のベースになるバインダー樹脂であり、一般の（メタ）アクリル酸エステルモノマー数種を共重合したものが使用できる。アクリル系重合体（ａ）を構成する（メタ）アクリル酸エステルモノマーとしては、粘着剤用途で公知のものが適用できる。
　本発明の保護フィルムは、高温に晒されることから、アクリル系重合体（ａ）も熱分解温度が高いものが好ましい。一般に、アクリル酸エステルモノマーから重合されたアクリル系重合体の方がメタクリル酸エステルモノマーから重合されたアクリル系重合体より耐熱性があるため（熱分解性面）、アクリル酸エステルモノマーを主（例えば、５０モル％以上）とするものがより好ましい。 -Acrylic polymer (a)-
The acrylic polymer (a) is a binder resin that serves as a base for the pressure-sensitive adhesive in the pressure-sensitive adhesive layer, and can be obtained by copolymerizing several general (meth) acrylic acid ester monomers. As the (meth) acrylic acid ester monomer constituting the acrylic polymer (a), those known for pressure-sensitive adhesives can be applied.
Since the protective film of the present invention is exposed to a high temperature, the acrylic polymer (a) preferably has a high thermal decomposition temperature. In general, an acrylic polymer polymerized from an acrylate monomer is more heat resistant than an acrylic polymer polymerized from a methacrylic acid ester monomer (thermally decomposable). 50 mol% or more) is more preferable.
　アクリル系重合体（ａ）を得るために用いるモノマーとして好適なものは、例えば、メチルアクリレート、メチルメタクリレート、エチルアクリレート、エチルメタクリレート、プロピルアクリレート、プロピルメタクリレート、ブチルアクリレート、ブチルメタクリレート、ヘキシルアクリレート、へキシルメタクリレート、オクチルアクリレート、オクチルメタクリレート、ノニルアクリレート、ノニルメタクリレート、ドデシルアクリレート、ドデシルメタクリレート等が挙げられる。
　これらのモノマーの側鎖アルキル基は直鎖状でも分岐状でもよい。また、上記のアクリル酸アルキルエステルモノマーは目的に応じて２種以上併用してもよい。 Suitable monomers for obtaining the acrylic polymer (a) are, for example, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, propyl acrylate, propyl methacrylate, butyl acrylate, butyl methacrylate, hexyl acrylate, hexyl. Examples include methacrylate, octyl acrylate, octyl methacrylate, nonyl acrylate, nonyl methacrylate, dodecyl acrylate, dodecyl methacrylate, and the like.
The side chain alkyl group of these monomers may be linear or branched. Moreover, you may use together 2 or more types of said acrylic acid alkylester monomers according to the objective.
　粘着層の特性（例えば粘着性等）を調整する点から、アクリル系重合体（ａ）は後述する架橋剤（ｃ）と反応する官能基を有することが好ましい。
　具体的には、アクリル系重合体（ａ）が有する架橋剤（ｃ）と反応する官能基としては、カルボン酸基、水酸基、グリシジル基などが好ましい。なお、カルボン酸基、水酸基、グリシジル基などは、架橋剤（ｃ）であるポリイソシアネートや多官能エポキシ樹脂と反応する。このような官能基を導入するには、かかる官能基を有する（メタ）アクリル酸エステルモノマーを共重合すればよい。
　架橋剤（ｃ）と反応する官能基を有する（メタ）アクリル酸エステルモノマーとしては、例えば、アクリル酸、メタクリル酸、クロトン酸、イタコン酸、マレイン酸、フマル酸等のカルボキシル基を有するモノマー；ヒドロキシエチルアクリレート、ヒドロキシエチルメタクリレート、ヒドロキシプロピルアクリレート、ヒドロキシプロピルメタクリレート等の水酸基を有するモノマー；グリシジルアクリレート、グリシジルメタクリレート等のグリシジル基を有するモノマー；等が挙げられる。 The acrylic polymer (a) preferably has a functional group that reacts with a cross-linking agent (c) described later from the viewpoint of adjusting the properties (eg, adhesiveness) of the adhesive layer.
Specifically, the functional group that reacts with the crosslinking agent (c) of the acrylic polymer (a) is preferably a carboxylic acid group, a hydroxyl group, a glycidyl group, or the like. In addition, a carboxylic acid group, a hydroxyl group, a glycidyl group, etc. react with polyisocyanate and polyfunctional epoxy resin which are crosslinking agents (c). In order to introduce such a functional group, a (meth) acrylic acid ester monomer having such a functional group may be copolymerized.
Examples of the (meth) acrylic acid ester monomer having a functional group that reacts with the crosslinking agent (c) include monomers having a carboxyl group such as acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid, and fumaric acid; And monomers having a hydroxyl group such as ethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate and hydroxypropyl methacrylate; monomers having a glycidyl group such as glycidyl acrylate and glycidyl methacrylate;
　また、粘着層を硬化させる点から、アクリル系重合体（ａ）は、側鎖にラジカル反応性の二重結合を有することが好ましい。このようなラジカル反応性の二重結合を導入するには、かかるラジカル反応性の二重結合を有する（メタ）アクリル酸エステルモノマーを、共重合した主ポリマー側鎖に付加反応すればよい。
　このような反応の組み合わせとしては、公知の手法である、主鎖にグリシジル（メタ）アクリレートを共重合しておき、二次反応として（メタ）アクリル酸を主鎖のグリシジル基に付加反応させる手法；主鎖に（メタ）アクリル酸を共重合しておき、二次反応としてグリシジル（メタ）アクリレートを（メタ）アクリル酸部分に付加反応させる手法；主鎖に前記水酸基を有するモノマーを共重合しておき、二次反応で２－メタクリロイルオキシエチルイソシアネート、２－アクリロイルオキシエチルイソシアネート、１，１－（ビスアクリロイルオキシメチル）エチルイソシアネート等のイソシアネート基を有する（メタ）アクリル酸エステルを水酸基部分に付加反応させる手法；などが挙げられる。
　本発明の保護フィルムのように、耐熱性が要求される用途では、熱分解性の点から、上に挙げた側鎖の付加反応としては、酸とグリシジルの反応の方が、イソシアネートと水酸基の反応より優れる。
　アクリル系重合体（ａ）が側鎖にラジカル反応性の二重結合を有することで、特定熱ラジカル発生剤（ｂ）から生じたラジカルにて、アクリル系重合体（ａ）同士での反応、又は、アクリル系重合体（ａ）と後述の２官能以上のアクリル系オリゴマーとの反応が可能となる。 Moreover, it is preferable that an acrylic polymer (a) has a radical reactive double bond in a side chain from the point which hardens an adhesion layer. In order to introduce such a radical reactive double bond, a (meth) acrylic acid ester monomer having such a radical reactive double bond may be added to the copolymerized main polymer side chain.
As a combination of such reactions, a well-known technique, in which glycidyl (meth) acrylate is copolymerized in the main chain, and (meth) acrylic acid is added to the glycidyl group of the main chain as a secondary reaction. A method in which (meth) acrylic acid is copolymerized in the main chain and glycidyl (meth) acrylate is added to the (meth) acrylic acid moiety as a secondary reaction; a monomer having the hydroxyl group in the main chain is copolymerized; In the secondary reaction, (meth) acrylic acid ester having an isocyanate group such as 2-methacryloyloxyethyl isocyanate, 2-acryloyloxyethyl isocyanate, 1,1- (bisacryloyloxymethyl) ethyl isocyanate is added to the hydroxyl portion. The method of making it react; etc. are mentioned.
In applications where heat resistance is required, such as the protective film of the present invention, from the viewpoint of thermal decomposability, as the side chain addition reaction mentioned above, the reaction of acid and glycidyl is more effective than the reaction of isocyanate and hydroxyl group. Better than reaction.
The acrylic polymer (a) has a radical-reactive double bond in the side chain so that the radicals generated from the specific thermal radical generator (b) react with each other between the acrylic polymers (a). Alternatively, the reaction between the acrylic polymer (a) and the later-described bifunctional or higher acrylic oligomer becomes possible.
　アクリル系重合体（ａ）は、組成物中、５０質量％以上９９．５質量％以下の範囲で含まれることが好ましく、６５質量％以上９９質量％以下の範囲で含まれることがより好ましい。 The acrylic polymer (a) is preferably contained in the composition in the range of 50% by mass to 99.5% by mass, and more preferably in the range of 65% by mass to 99% by mass.
－特定熱ラジカル発生剤（ｂ）－
　本発明で用いる特定熱ラジカル発生剤（ｂ）は、以下のような点から選択された成分である。
　即ち、本発明では、粘着層を得る際に用いる各成分（アクリル系重合体（ａ）、特定熱ラジカル発生剤（ｂ）、及び架橋剤（ｃ）を含む）を溶剤に溶解した粘着層形成用塗布液を、ポリイミド基材（又はセパレータ）上に、塗布、乾燥して、保護フィルムが作製される。
　この乾燥の際に熱がかかるため、かかる乾燥の温度では、分解が始まり難い分解温度のものを選択するのが好ましい。また、室温での保存安定性面でも分解温度が高いものが好ましい。一方、分解温度が高すぎると、分解させるために高温にする必要が生じ、その高温条件で粘着性が昂進してしまい、半導体ウェハからの剥離が難しくなってしまうので、、分解温度が高すぎるものも好ましくない。
　以上の点から、本発明に用いられる特定熱ラジカル発生剤（ｂ）は、１分間半減期温度が１４０℃以上２００℃以下である必要がある。
　ここで、特定熱ラジカル発生剤の１分間半減期温度は、１４５℃以上１８０℃以下が好ましい。 -Specific thermal radical generator (b)-
The specific thermal radical generator (b) used in the present invention is a component selected from the following points.
That is, in the present invention, an adhesive layer formed by dissolving each component (including the acrylic polymer (a), the specific thermal radical generator (b), and the crosslinking agent (c)) used in obtaining the adhesive layer in a solvent. The coating liquid is applied on a polyimide substrate (or separator) and dried to produce a protective film.
Since heat is applied during the drying, it is preferable to select a temperature at which the decomposition is difficult to start at the drying temperature. Also, those having a high decomposition temperature are preferable in terms of storage stability at room temperature. On the other hand, if the decomposition temperature is too high, it will be necessary to raise the temperature to decompose, and the adhesiveness will increase under the high temperature conditions, making it difficult to peel from the semiconductor wafer, so the decomposition temperature is too high. Things are also not preferred.
From the above points, the specific thermal radical generator (b) used in the present invention needs to have a one-minute half-life temperature of 140 ° C. or higher and 200 ° C. or lower.
Here, the 1 minute half-life temperature of the specific thermal radical generator is preferably 145 ° C. or higher and 180 ° C. or lower.
　また、上記の乾燥の際、溶剤と一緒に揮発してしまうと、粘着層中の特定熱ラジカル発生剤量（ｂ）が少なくなり、十分な反応が得られ難くなるため、分子量が大きく、揮発し難いものを選ぶことが好ましい。
　このような点から、特定熱ラジカル発生剤の分子量は２００～１０００が好ましく、２００～７００がより好ましく、３００～７００がさらに好ましい。 In addition, if the solvent is volatilized together with the solvent during the drying, the amount of the specific thermal radical generator (b) in the adhesive layer decreases, and it becomes difficult to obtain a sufficient reaction. It is preferable to select one that is difficult to do.
From such points, the molecular weight of the specific thermal radical generator is preferably 200 to 1000, more preferably 200 to 700, and further preferably 300 to 700.
　特定熱ラジカル発生剤（ｂ）としては、１分間半減期温度が上記の範囲である、公知の過酸化物、アゾ化合物などが用いられる。
　特定熱ラジカル発生剤（ｂ）の具体例としては、以下に示すものが挙げられるが、本発明はこれらに限定されるものではない。
　なお、以下の具体例には化合物名に加え、市販品名（全て日油株式会社製）、分子量、及び１分間半減期温度を併記した。 As the specific thermal radical generator (b), known peroxides, azo compounds and the like having a 1 minute half-life temperature in the above range are used.
Specific examples of the specific thermal radical generator (b) include the following, but the present invention is not limited thereto.
In the following specific examples, in addition to the compound name, a commercial product name (all manufactured by NOF Corporation), molecular weight, and 1-minute half-life temperature are also shown.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　特定熱ラジカル発生剤（ｂ）の具体的な市販品としては、例えば、日油株式会社製のパーヘキサＭＣ、パーヘキサＴＭＨ、パーヘキサＨＣ、パーヘキサＣ、パーテトラＡ、パーヘキシルＩ、パーブチル３５５、パーブチルＬ、パーブチルＥ、パーヘキシルＺ、パーヘキサ２５Ｚ、パーヘキサ２２、パーヘキサＶ、パーブチルＰ、パークミルＤ、パーヘキシルＤ、パーヘキサ２５Ｂ、パーブチルＣ、パーヘキシン２５Ｂ等が好ましい。 Specific commercial products of the specific thermal radical generator (b) include, for example, Perhexa MC, Perhexa TMH, Perhexa HC, Perhexa C, Pertetra A, Perhexyl I, Perbutyl 355, Perbutyl L, Perbutyl manufactured by NOF Corporation. E, perhexyl Z, perhexa 25Z, perhexa 22, perhexa V, perbutyl P, park mill D, perhexyl D, perhexa 25B, perbutyl C, perhexine 25B, and the like are preferable.
　特定熱ラジカル発生剤（ｂ）の添加量としては、アクリル系重合体（ａ）を構成する単量体の総量１００質量部に対して、好ましくは０．１質量部以上５質量部以下、より好ましくは０．２質量部以上２質量部以下であり、更に好ましくは０．３質量部以上１質量部以下である。
　特定熱ラジカル発生剤の添加量が少なすぎると、粘着層の熱硬化が不十分で粘着性が昂進してしまう問題を生じることがあり、一方、多すぎると、Ｘ線光電子分光分析（ＸＰＳ／ＥＳＣＡ）や微小パーティクル検出器などで検出される分解物（ラジカルの再結合物など）の物質による半導体ウェハの汚染や真空装置の汚染が起きる問題を生じることがある。 The amount of the specific thermal radical generator (b) added is preferably 0.1 parts by mass or more and 5 parts by mass or less with respect to 100 parts by mass of the total amount of monomers constituting the acrylic polymer (a). Preferably they are 0.2 mass part or more and 2 mass parts or less, More preferably, they are 0.3 mass part or more and 1 mass part or less.
If the amount of the specific thermal radical generator added is too small, there may be a problem that the adhesive layer is not sufficiently cured by heat and the tackiness is increased. On the other hand, if the amount is too large, X-ray photoelectron spectroscopy (XPS / There may be a problem that contamination of a semiconductor wafer or contamination of a vacuum apparatus is caused by a substance (such as a recombination product of radicals) detected by an ESCA) or a minute particle detector.
－架橋剤（ｃ）－
　本発明における架橋剤（ｃ）は、アクリル系重合体（ａ）と反応し、アクリル系重合体（ａ）の架橋体（３次元架橋体）を形成しうる成分である。
　アクリル系重合体（ａ）を架橋体とすることで、粘着層の初期の粘着力の調整や、テープのカットし易さ（カット面粘着層の切れやすさ）、加圧変形性などを調整でき、更にアクリル系重合体（ａ）の主鎖の熱分解を抑制することができる。
　架橋剤（ｃ）としては、アクリル系の粘着剤用として一般的な架橋剤である、イソシアネート系、エポキシ系の架橋剤などが用いられる。 -Crosslinking agent (c)-
The crosslinking agent (c) in the present invention is a component that can react with the acrylic polymer (a) to form a crosslinked body (three-dimensional crosslinked body) of the acrylic polymer (a).
By adjusting the acrylic polymer (a) to a crosslinked product, adjustment of the initial adhesive strength of the adhesive layer, ease of cutting of the tape (easiness of cutting the adhesive layer on the cut surface), pressure deformation, etc. are adjusted. Furthermore, thermal decomposition of the main chain of the acrylic polymer (a) can be suppressed.
As the crosslinking agent (c), an isocyanate-based or epoxy-based crosslinking agent, which is a general crosslinking agent for an acrylic pressure-sensitive adhesive, is used.
　また、前述したアクリル系重合体（ａ）の耐熱性（熱分解性）向上の点から、耐熱性（熱分解性）の高い架橋剤を選択することが好ましい。 Further, it is preferable to select a crosslinking agent having high heat resistance (thermal decomposability) from the viewpoint of improving the heat resistance (thermal decomposability) of the acrylic polymer (a).
　本発明において、好ましい架橋剤（ｃ）としては、以下に示すものが挙げられるが、本発明はこれらに限定されるものではない。
　即ち、ソルビトールポリグリシジルエーテル、ポリグリセロールポリグリシジルエーテル、ペンタエリスリトールポリグリシジルエーテル、ジグリセロールポリグリシジルエーテル、グリセロールポリグリシジルエーテル、ネオペンチルグリコールジグリシジルエーテル、レソルシンジグリシジルエーテル、商品名になるが三菱ガス化学製テトラッドＣやテトラッドＸ等のエポキシ系化合物；テトラメチレンジイソシアネート、ヘキサメチレンジイソシアネート、トリメチロールプロパンのトルエンジイソシアネート３付加物、ポリイソシアネート、イソシアヌレート型イソシアネート等のイソシアネート系化合物；等が挙げられる。 In the present invention, preferred crosslinking agents (c) include those shown below, but the present invention is not limited thereto.
That is, sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, diglycerol polyglycidyl ether, glycerol polyglycidyl ether, neopentyl glycol diglycidyl ether, resorcin diglycidyl ether Examples include chemical epoxy compounds such as tetrad C and tetrad X; isocyanate compounds such as tetramethylene diisocyanate, hexamethylene diisocyanate, toluene diisocyanate triadduct of trimethylolpropane, polyisocyanate, isocyanurate type isocyanate, and the like.
　架橋剤が少ないと、硬化前の粘着層が軟質で流動性のあるものになり、ウェハ表面に対する濡れ性や凹凸追従性に優れる傾向がある。しかし、架橋剤が少ないと、形状安定性が悪くなり、本発明の保護フィルムを巻物として保存する場合に段差痕が発生しやくなるおそれがある。また、本発明の保護フィルムをカットするときに粘着剤の切れが悪くなるおそれがある。
　一方、架橋剤が多いと、硬化前の粘着層は硬質となり、ウェハ表面に対する濡れ性や凹凸追従性は得られ難く、真空加熱下にて保護フィルムの浮きが生じることがある。
　本発明においては、上記のような点を考慮し、架橋剤（ｃ）の添加量を決定すればよい。
　架橋剤の適正な添加量は、本発明における組成物に添加される２官能以上のアクリル系オリゴマーが多い場合は、上記の軟質な粘着剤になる傾向が助長されるので、より多く添加するとよい。
　例えば、架橋剤（ｃ）の添加量としては、アクリル系重合体（ａ）を構成する単量体の総量１００質量部に対して、０．１質量部以上２０質量部以下が好ましく、０．２質量部以上１０質量部以下がより好ましい。 When the amount of the crosslinking agent is small, the pressure-sensitive adhesive layer before curing becomes soft and fluid and tends to be excellent in wettability and unevenness followability to the wafer surface. However, when there are few crosslinking agents, shape stability will worsen and there exists a possibility that a level | step difference mark may become easy to produce | generate when the protective film of this invention is preserve | saved as a roll. Moreover, when the protective film of this invention is cut, there exists a possibility that the cut of an adhesive may worsen.
On the other hand, when the amount of the crosslinking agent is large, the adhesive layer before curing becomes hard, it is difficult to obtain wettability and unevenness followability to the wafer surface, and the protective film may float under vacuum heating.
In the present invention, the addition amount of the crosslinking agent (c) may be determined in consideration of the above points.
The proper addition amount of the crosslinking agent is preferably increased because the tendency to become a soft adhesive is promoted when there are many bifunctional or higher acrylic oligomers added to the composition of the present invention. .
For example, the addition amount of the crosslinking agent (c) is preferably 0.1 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the total amount of monomers constituting the acrylic polymer (a). 2 parts by mass or more and 10 parts by mass or less are more preferable.
－２官能以上のアクリル系オリゴマー（ｄ）－
　本発明における熱硬化性粘着層を得るための組成物は、２官能以上のアクリル系オリゴマー（ｄ）を更に含むことが好ましい。
　２官能以上のアクリル系オリゴマー（ｄ）は、ラジカル反応性の二重結合を２つ以上有するアクリル系オリゴマーであって、特定熱ラジカル発生剤（ｂ）によって発生するラジカルで反応し、粘着層の硬化に寄与する成分である。
　前記したアクリル系重合体（ａ）が、側鎖にラジカル反応性の二重結合を有さない場合は、粘着層を熱硬化させる成分として必須になる。 -Acrylic oligomer (d)-
It is preferable that the composition for obtaining the thermosetting adhesive layer in the present invention further contains a bifunctional or higher functional acrylic oligomer (d).
The bifunctional or higher-functional acrylic oligomer (d) is an acrylic oligomer having two or more radical-reactive double bonds, and reacts with radicals generated by the specific thermal radical generator (b). It is a component that contributes to curing.
When the above-mentioned acrylic polymer (a) does not have a radical reactive double bond in the side chain, it becomes essential as a component for thermosetting the adhesive layer.
　熱硬化後の粘着層が硬く脆い場合、粘着層がウェハ表面の凹凸に食い込んだまま破断して、ウェハ表面に粘着層の一部が残留（のり残りとも称する）してしまうことがある。このため、熱硬化後の粘着層の引張破断時伸びが大きくなるように、２官能以上のアクリル系オリゴマー（ｄ）の添加量、官能基数などを調整するとよい。官能基数が多く分子量が小さいものを多く添加すると硬く、もろくなるおそれがある。一方、官能基数が少なく分子量が大きなものを多く添加すると、硬化物としては、軟質になってしまい、硬化不十分で粘着昂進してのり残りしてしまうおそれがある。
　２官能以上のアクリル系オリゴマー（ｄ）としては、６官能以下のものが好ましく、３官能以上、５官能以下であることがより好ましい。
　本発明の保護フィルムは耐熱性を要するので、２官能以上のアクリル系オリゴマー（ｄ）においても、耐熱性（熱分解しにくい）の高い構造のものを選択することが好ましい。耐熱性の点からは、ウレタン結合を有するものより、エステル結合を有するものが好ましい。 When the pressure-sensitive adhesive layer after heat curing is hard and brittle, the pressure-sensitive adhesive layer may break while it is biting into the irregularities on the wafer surface, and a part of the pressure-sensitive adhesive layer may remain on the wafer surface (also referred to as residue). For this reason, it is good to adjust the addition amount, the number of functional groups, etc. of bifunctional or more acrylic oligomer (d) so that the elongation at the time of the tensile fracture of the adhesion layer after thermosetting may become large. If a large number of functional groups having a large molecular weight is added, it may be hard and brittle. On the other hand, if a large amount of a functional group having a small number of functional groups is added, the cured product becomes soft, and there is a risk that the cured product is insufficiently cured and remains stuck.
The bifunctional or higher acrylic oligomer (d) is preferably hexafunctional or lower, more preferably trifunctional or higher and pentafunctional or lower.
Since the protective film of the present invention requires heat resistance, it is preferable to select a bifunctional or higher acrylic oligomer (d) having a structure with high heat resistance (not easily thermally decomposed). From the viewpoint of heat resistance, those having an ester bond are preferable to those having a urethane bond.
　また、アクリル系オリゴマー（ｄ）の分子量としては、硬化物性の点から、２００以上１００００以下が好ましく、３００以上５０００以下がより好ましい。 Further, the molecular weight of the acrylic oligomer (d) is preferably from 200 to 10,000, more preferably from 300 to 5,000, from the viewpoint of cured properties.
　２官能以上のアクリル系オリゴマー（ｄ）の具体例としては、市販のウレタンアクリレート、エポキシアクリレート、ポリエステルアクリレート、ポリエーテルアクリレート、ペンタエリスリトールポリアクリレート、ジペンタエリスリトールポリアクリレート、エトキシ化イソシアヌル酸トリアクリレート、トリメチロールプロパントリアクリレート、ジトリメチロールプロパンテトラアクリレート等が挙げられる。 Specific examples of the bifunctional or higher acrylic oligomer (d) include commercially available urethane acrylate, epoxy acrylate, polyester acrylate, polyether acrylate, pentaerythritol polyacrylate, dipentaerythritol polyacrylate, ethoxylated isocyanuric acid triacrylate, tri Examples include methylolpropane triacrylate and ditrimethylolpropane tetraacrylate.
　２官能以上のアクリル系オリゴマー（ｄ）は、アクリル系重合体（ａ）が、側鎖にラジカル反応性の二重結合を有する場合は無添加でもよいが、添加することで、２官能以上のアクリル系オリゴマー（ｄ）が低分子量成分として機能し、熱硬化前の粘着層のウェハ表面に対する凹凸追従性、濡れ性が向上する。また、２官能以上のアクリル系オリゴマー（ｄ）を多く使用すると、特に官能基数が多い場合、硬化後の粘着層が硬く脆くなり、前記した粘着層の破断が生じることがある。
　上記の点から、２官能以上のアクリル系オリゴマー（ｄ）の添加量は、アクリル系重合体（ａ）１００質量部に対して、０質量部以上１００質量部以下、より好ましくは０質量部５０質量部以下が適当である。
　また、アクリル系重合体（ａ）が、側鎖にラジカル反応性の二重結合を有さない場合は、粘着層を熱硬化させる成分として必須になるが、２官能以上のアクリル系オリゴマー（ｄ）が少ないと、粘着層の熱硬化が不十分で、ウェハ表面に粘着層の一部が残留（凝集破壊）することがある。また、２官能以上のアクリル系オリゴマー（ｄ）を多く使用すると、上記の粘着層の破断が生じることがある。
　上記の点から、２官能以上のアクリル系オリゴマー（ｄ）を必須とする場合の添加量は、アクリル系重合体（ａ）１００質量部に対して、１質量部以上１００質量部以下、より好ましくは２０質量部以上５０質量部以下が適当である。 The bifunctional or higher functional acrylic oligomer (d) may be added in the case where the acrylic polymer (a) has a radical reactive double bond in the side chain. The acrylic oligomer (d) functions as a low molecular weight component, and the unevenness followability and wettability of the pressure-sensitive adhesive layer before thermosetting to the wafer surface are improved. Moreover, when many bifunctional or higher functional acrylic oligomers (d) are used, particularly when the number of functional groups is large, the cured adhesive layer becomes hard and brittle, and the adhesive layer described above may break.
From the above points, the addition amount of the bifunctional or higher-functional acrylic oligomer (d) is 0 to 100 parts by mass, more preferably 0 to 50 parts by mass with respect to 100 parts by mass of the acrylic polymer (a). Less than parts by mass is appropriate.
Further, when the acrylic polymer (a) does not have a radical-reactive double bond in the side chain, it is essential as a component for thermally curing the adhesive layer, but a bifunctional or higher-functional acrylic oligomer (d ) Is insufficient, the thermosetting of the adhesive layer is insufficient, and a part of the adhesive layer may remain (cohesive failure) on the wafer surface. Moreover, when many bifunctional or higher functional acrylic oligomers (d) are used, the adhesive layer may break.
From the above points, the amount of addition when the bifunctional or higher functional acrylic oligomer (d) is essential is 1 to 100 parts by mass, more preferably 100 parts by mass with respect to 100 parts by mass of the acrylic polymer (a). 20 mass parts or more and 50 mass parts or less are suitable.
－粘着層の厚み－
　以上のような各成分を含む組成物にて得られた粘着層の厚みは、ウェハ表面の凹凸に対して十分に追従できる厚みに形成することが好ましい。
　具体的には、粘着層の厚みは１０μｍ以上１００μｍ以下、より好ましくは２０μｍ以上５０μｍ以下が適当である。 -Thickness of adhesive layer-
The thickness of the pressure-sensitive adhesive layer obtained from the composition containing each component as described above is preferably formed to a thickness that can sufficiently follow the irregularities on the wafer surface.
Specifically, the thickness of the adhesive layer is suitably 10 μm or more and 100 μm or less, more preferably 20 μm or more and 50 μm or less.
（ポリイミド基材）
　本発明におけるポリイミド基材は、以下のような点から選択されたものである。
　即ち、基材を真空加熱下に供する際、基材が軟化してしまうと、接触している部材に固着してしまうので好ましくない。また、高温でも高い弾性率を維持しうることが好ましい。
　また、本発明の保護フィルムが貼付される半導体ウェハ（シリコンウェハ）は、１５０μｍ以下、場合によっては１００μｍ以下と薄く加工されている。このような薄い半導体ウェハと保護フィルムとを貼付された後、加熱すると、基材の線膨張率が半導体ウェハのシリコンの熱膨張率から大きくずれていると、半導体ウェハに反りが発生してしまう。真空加熱下の装置内で半導体ウェハが反ると、ウェハ保持手段から外れて搬送不能になる問題やウェハが割れる問題を生じる。この点から、基材の熱膨張係数がシリコンに近い材料が好ましい。また、基材の製造工程で基材内に残留した応力などによって、加熱工程で基材が熱収縮すると、やはり反りを生じて搬送や割れ側面で問題となる。
　このように基材には、高温で軟化しない点、薄い半導体ウェハの反りを抑える点から、熱分解し難く、高温時の弾性率を維持すること、熱膨張率が半導体ウェハと大きくずれないこと、熱収縮率が低いことなどが要求される。
　そのような点を考慮すると、材料としてはポリイミドが選択される。 (Polyimide substrate)
The polyimide base material in the present invention is selected from the following points.
That is, when the base material is subjected to vacuum heating, if the base material is softened, it is not preferable because the base material is fixed to the contacting member. Moreover, it is preferable that a high elastic modulus can be maintained even at high temperatures.
The semiconductor wafer (silicon wafer) to which the protective film of the present invention is attached is processed to be as thin as 150 μm or less, and in some cases, 100 μm or less. When such a thin semiconductor wafer and a protective film are applied and then heated, if the linear expansion coefficient of the base material is greatly deviated from the thermal expansion coefficient of silicon of the semiconductor wafer, the semiconductor wafer is warped. . When the semiconductor wafer is warped in the apparatus under vacuum heating, there arises a problem that the wafer is detached from the wafer holding means and cannot be transported or the wafer is broken. From this point, a material having a thermal expansion coefficient close to that of silicon is preferable. Further, when the base material is thermally contracted in the heating process due to stress remaining in the base material in the manufacturing process of the base material, warping is also caused, which causes a problem in conveyance and crack side surfaces.
In this way, the base material does not soften at high temperatures and suppresses warping of thin semiconductor wafers, so it is difficult to thermally decompose, maintain the elastic modulus at high temperatures, and the thermal expansion coefficient does not deviate significantly from the semiconductor wafer. In addition, low heat shrinkage is required.
In consideration of such points, polyimide is selected as the material.
　また、真空加熱下で行われる工程の前には、保護フィルムに含有される水分を低減する乾燥工程を行う。この乾燥工程において、保護フィルムから水分を除きやすい点から、ポリイミド基材としては、水蒸気の透過性のよいものを選択することが好ましい。 Moreover, before the process performed under vacuum heating, a drying process for reducing the moisture contained in the protective film is performed. In this drying step, it is preferable to select a polyimide substrate having good water vapor permeability from the viewpoint of easily removing moisture from the protective film.
　ポリイミド基材と粘着層の界面の接着が悪いと、保護フィルムの剥離時に粘着剤がウェハ表面に残留してのり残りとなってしまうことがある。
　そのため、ポリイミド基材には、表面処理（公知の、放電処理（コロナ、プラズマ）やカップリング剤処理など）を施したり、接着層を設けるなどして、粘着層とポリイミド基材との接着力を高めることが好ましい。 If the adhesion between the polyimide substrate and the adhesive layer is poor, the adhesive may remain on the wafer surface when the protective film is peeled off.
Therefore, the adhesive strength between the pressure-sensitive adhesive layer and the polyimide base material is obtained by subjecting the polyimide base material to a surface treatment (such as a known discharge treatment (corona, plasma) or a coupling agent treatment) or an adhesive layer. Is preferably increased.
　ポリイミド基材の厚みは、２５μｍ以上１００μｍ以下が好ましく、３８μｍ以上５０μｍ以下がより好ましい。
　ポリイミド基材が薄すぎると、貼付時にシワが入りやすくなることがあり、一方、厚すぎると、水蒸気の透過性が悪くなったり、半導体ウェハの表面の凹凸への追従性が悪くなることがある。 The thickness of the polyimide base material is preferably 25 μm or more and 100 μm or less, and more preferably 38 μm or more and 50 μm or less.
If the polyimide base material is too thin, wrinkles may be easily formed at the time of sticking. On the other hand, if it is too thick, the water vapor permeability may be deteriorated or the followability to the irregularities on the surface of the semiconductor wafer may be deteriorated. .
　ポリイミド基材としては、市販ポリイミド基材を用いればよい。
　具体的には、例えば、東レ・デュポン社のカプトン（登録商標）、カネカ社のアピカル（登録商標）、宇部興産のユーピレックス（登録商標）等が商品化されており、これらを使用することができる。 A commercially available polyimide substrate may be used as the polyimide substrate.
Specifically, for example, Kapton (registered trademark) of Toray DuPont, Apical (registered trademark) of Kaneka, Upilex (registered trademark) of Ube Industries, etc. have been commercialized and can be used. .
－保護フィルムの作製－
　保護フィルムは以下のようにして作製される。
　まず、粘着層を得るために用いる組成物を構成する各成分を溶剤に溶解して、粘着層形成用塗布液を調製する。
　調製された粘着層形成用塗布液を、乾燥後の粘着層の厚みに応じた厚みで、塗布装置でポリイミド基材上に塗布し、その後、乾燥炉で乾燥することで保護フィルムが作製される。
　なお、粘着層形成用塗布液を、乾燥後の粘着層の厚みに応じた厚みで、塗布装置でポリイミド基材又はセパレータ上に塗布し、その後、乾燥炉で乾燥して、更に、塗布面をセパレータ又はポリイミド基材と貼り合せることで、セパレータ／粘着層／ポリイミド基材の構成の積層体を得る方法を用いて保護フィルムを作成してもよい。このような積層体の保護フィルムは、半導体ウェハに貼付される前に、セパレータを剥離すればよい。
　なお、上記の粘着層形成用塗布液の乾燥では、特定熱ラジカル発生剤（ｂ）を分解させない、温度、乾燥炉での滞留時間を選択することが好ましい。また、乾燥において、溶剤等の揮発成分を十分除くことで、真空加熱下における保護フィルムの浮きを抑制しうる点も考慮して、温度、乾燥炉での滞留時間を選択することが好ましい。
　具体的には、例えば、乾燥工程における温度は、６０℃以上１３０℃以下が好ましく、滞留時間としては、１分以上１０分以下が好ましい。 -Production of protective film-
The protective film is produced as follows.
First, each component which comprises the composition used in order to obtain an adhesion layer is melt | dissolved in a solvent, and the coating liquid for adhesion layer formation is prepared.
The prepared adhesive layer forming coating solution is applied on a polyimide substrate with a coating device at a thickness corresponding to the thickness of the adhesive layer after drying, and then dried in a drying furnace to produce a protective film. .
The pressure-sensitive adhesive layer-forming coating solution is applied on the polyimide substrate or separator with a coating device at a thickness corresponding to the thickness of the pressure-sensitive adhesive layer after drying, and then dried in a drying furnace. You may create a protective film using the method of obtaining the laminated body of the structure of a separator / adhesion layer / polyimide base material by bonding with a separator or a polyimide base material. Such a protective film of the laminate may be peeled off before being attached to the semiconductor wafer.
In the drying of the coating solution for forming the adhesive layer, it is preferable to select a temperature and a residence time in the drying furnace that do not decompose the specific thermal radical generator (b). In drying, it is preferable to select the temperature and the residence time in the drying furnace in consideration of sufficiently removing the volatile component such as a solvent so that the protective film can be prevented from floating under vacuum heating.
Specifically, for example, the temperature in the drying step is preferably 60 ° C. or higher and 130 ° C. or lower, and the residence time is preferably 1 minute or longer and 10 minutes or shorter.
－保護フィルムの適用用途－
　本発明の保護フィルムは、以下の（１）～（４）の工程を含む半導体装置の製造方法における保護フィルムとして用いられることが好ましい。
　（１）半導体ウェハの回路形成面に、熱硬化性粘着層を有する保護フィルムを当該回路形成面と当該熱硬化性粘着層が接するように貼付する貼付工程
　（２）前記保護フィルムが貼付された前記半導体ウェハを１２０℃以上１８０℃以下の温度で加熱する加熱工程
　（３）（２）の加熱工程後、前記保護フィルムが貼付された前記半導体ウェハを真空下に静置する静置工程と、
　（４）（３）の静置工程後、真空且つ２００℃以上の条件下で、前記半導体ウェハにおける回路非形成面に対し、金属蒸着、金属スパッタ、及びイオン注入のいずれか１つの処理を施す処理工程
　ここで、上記（１）の工程は後述する（Ａ）貼付工程に、上記（２）の工程は後述する（Ｃ）加熱工程に、上記（３）の工程は後述する（Ｄ）静置工程に、上記（４）の工程は後述する（Ｅ）真空加熱下での処理工程に、それぞれ対応する。各工程の詳細は、対応する（Ａ）貼付工程、（Ｃ）加熱工程、（Ｄ）静置工程、及び（Ｅ）真空加熱下での処理工程と同様であるため、ここでは省略する。 -Application of protective film-
The protective film of the present invention is preferably used as a protective film in a method for producing a semiconductor device including the following steps (1) to (4).
(1) A sticking step of sticking a protective film having a thermosetting adhesive layer on a circuit forming surface of a semiconductor wafer so that the circuit forming surface and the thermosetting adhesive layer are in contact with each other. (2) The protective film is attached. Heating step of heating the semiconductor wafer at a temperature of 120 ° C. or higher and 180 ° C. or lower (3) After the heating step of (2), a stationary step of standing the semiconductor wafer to which the protective film is attached under vacuum,
(4) After the stationary step of (3), any one of metal vapor deposition, metal sputtering, and ion implantation is performed on the non-circuit-formed surface of the semiconductor wafer under vacuum and at 200 ° C. or higher. Processing Step Here, the step (1) is described later in (A) a sticking step, the step (2) is described in (C) a heating step, and the step (3) is described in (D) static. The step (4) corresponds to the (E) processing step under vacuum heating described later. The details of each step are the same as the corresponding (A) sticking step, (C) heating step, (D) standing step, and (E) processing step under vacuum heating, and thus are omitted here.
（半導体装置の製造方法）
　次に、本発明の保護フィルムを用いた半導体装置の製造方法について説明する。
　本発明の半導体装置の製造方法は、
　（Ａ）半導体ウェハの回路形成面に、本発明の保護フィルムを、当該回路形成面に前記熱硬化性粘着層が接するように貼付する貼付工程と、
　（Ｂ）前記半導体ウェハにおける回路非形成面を研削する研削工程と、
　（Ｃ）前記保護フィルムが貼付され、回路非形成面が研削された前記半導体ウェハを１２０℃以上１８０℃以下の温度で加熱する加熱工程と、
　（Ｄ）（Ｃ）の加熱工程後、前記保護フィルムが貼付された前記半導体ウェハを真空下に静置する静置工程と、
　（Ｅ）（Ｄ）の静置工程後、真空且つ２００℃以上の条件下で、前記保護フィルムが貼付された前記半導体ウェハにおける回路非形成面に対し、金属蒸着、金属スパッタ、及びイオン注入のいずれか１つの処理を施す処理工程と、
　（Ｆ）前記保護フィルムを前記半導体ウェハから剥離する剥離工程と、
　を含む、半導体装置の製造方法である。
　以下、各工程について説明する。 (Method for manufacturing semiconductor device)
Next, the manufacturing method of the semiconductor device using the protective film of this invention is demonstrated.
A method for manufacturing a semiconductor device of the present invention includes:
(A) An attaching step of attaching the protective film of the present invention to the circuit forming surface of the semiconductor wafer so that the thermosetting adhesive layer is in contact with the circuit forming surface;
(B) a grinding step of grinding a non-circuit-formed surface of the semiconductor wafer;
(C) a heating step of heating the semiconductor wafer to which the protective film is attached and the non-circuit-formed surface is ground at a temperature of 120 ° C. or higher and 180 ° C. or lower;
(D) after the heating step of (C), a standing step of standing the semiconductor wafer to which the protective film is stuck under vacuum;
(E) After the standing step of (D), under vacuum and at a temperature of 200 ° C. or higher, metal deposition, metal sputtering, and ion implantation are performed on the non-circuit-formed surface of the semiconductor wafer to which the protective film is attached. A processing step of applying any one of the processing;
(F) a peeling step of peeling the protective film from the semiconductor wafer;
A method for manufacturing a semiconductor device including:
Hereinafter, each step will be described.
－（Ａ）貼付工程－
　本発明における（Ａ）貼付工程では、半導体ウェハの回路形成面に、本発明の保護フィルムにおける熱硬化性粘着層が接するように貼付する。
　かかる（Ａ）貼付工程は、（Ｂ）研削工程の前又は後に行われる。
　（Ａ）貼付工程が（Ｂ）研削工程の前に行われる場合、本発明の保護フィルムが貼付された半導体ウェハがそのまま（Ｂ）研削工程に適用される。
　また、（Ａ）貼付工程が（Ｂ）研削工程の後に行われる場合、（Ｂ）研削工程の前には、半導体ウェハの回路形成面に、公知の保護フィルムにおける粘着層が接するように貼付する工程を行う。また、公知の保護フィルムが貼付された半導体ウェハを用い（Ｂ）研削工程を行った後、公知の保護フィルムを半導体ウェハから剥離する工程を行う。
　工程数が少なく、保護フィルムの貼り換えを行う必要がないことから、（Ａ）貼付工程は（Ｂ）研削工程の前に行うことが好ましい。 -(A) Pasting process-
In the (A) sticking step in the present invention, the sticking is performed so that the thermosetting adhesive layer in the protective film of the present invention is in contact with the circuit forming surface of the semiconductor wafer.
This (A) sticking process is performed before or after the (B) grinding process.
When the (A) sticking step is performed before the (B) grinding step, the semiconductor wafer to which the protective film of the present invention is stuck is applied to the (B) grinding step as it is.
Moreover, when (A) a sticking process is performed after (B) a grinding process, it sticks so that the adhesion layer in a well-known protective film may contact | connect the circuit formation surface of a semiconductor wafer before a (B) grinding process. Perform the process. Moreover, after performing the (B) grinding process using the semiconductor wafer with which the well-known protective film was stuck, the process of peeling a well-known protective film from a semiconductor wafer is performed.
Since the number of steps is small and there is no need to replace the protective film, it is preferable to perform the (A) pasting step before the (B) grinding step.
　本発明の保護フィルムの半導体ウェハへの貼付には、公知のテープ貼り機が適用可能である。
　ウェハ表面の回路の凹凸に空気をかまずに貼るためには、真空貼り機を使用することが好ましい。空気をかむと、（Ｅ）真空加熱下で行われる処理工程にて保護フィルムの浮きのきっかけになるので好ましくない。 A known tape applicator can be applied to the protective film of the present invention applied to the semiconductor wafer.
In order to apply air to the irregularities of the circuit on the wafer surface without applying air, it is preferable to use a vacuum applicator. It is not preferable to bite air because (E) the protective film floats in the processing step performed under vacuum heating.
－（Ｂ）研削工程－
　本発明における（Ｂ）研削工程では、半導体ウェハにおける回路非形成面（ウェハ裏面）を研削する。
　（Ｂ）研削工程では、例えば、研削機のチャックテーブル等に、本発明の保護フィルム又は従来の保護フィルムが貼付された半導体ウェハを、ポリイミド基材を介して固定し、半導体ウェハにおける回路非形成面（ウェハ裏面）を研削する。
　研削が終了した後、半導体ウェハに従来の保護フィルムが貼付されていた場合は、その保護フィルムを剥離する。 -(B) Grinding process-
In the grinding step (B) in the present invention, the non-circuit-formed surface (wafer back surface) of the semiconductor wafer is ground.
(B) In the grinding process, for example, a semiconductor wafer to which the protective film of the present invention or the conventional protective film is attached is fixed to a chuck table of a grinding machine via a polyimide base material, and a circuit is not formed on the semiconductor wafer. Grind the surface (wafer back).
After the grinding is finished, when the conventional protective film is stuck on the semiconductor wafer, the protective film is peeled off.
　ウェハ裏面の研削が完了した後、保護フィルムを付けたままの半導体ウェハに対して、ウェハ裏面のケミカルエッチング、ポリッシング等の薬液によるエッチング処理工程を施すこともある。 After grinding of the back surface of the wafer, the semiconductor wafer with the protective film attached may be subjected to an etching process step using a chemical solution such as chemical etching or polishing of the back surface of the wafer.
　また、ウェハ裏面の研削が完了した後やエッチング処理工程が施された後は、本発明の保護フィルムが貼付された半導体ウェハに対し、かかる保護フィルム中の水分を除去するための予備加熱を行ってもよい。
　本発明の保護フィルムは、アクリル系粘着剤とポリイミド基材で構成されており、どちらも吸湿率の高い材料である。研削工程やエッチング処理工程は水を使用した工程であるため、本発明の保護フィルムは吸湿した状態となる。
　この吸湿した状態の保護フィルムを、（Ｃ）加熱工程にて加熱すると吸湿した水分の急激な膨張で、浮きが発生することがある。これを抑制するために、オーブン等を使用し、本発明の保護フィルムが貼付された半導体ウェハを、６０℃以上１００℃以下で数分～数１０分予備加熱乾燥することが好ましい。 In addition, after the grinding of the back surface of the wafer is completed or the etching process is performed, the semiconductor wafer to which the protective film of the present invention is attached is preheated to remove moisture in the protective film. May be.
The protective film of the present invention is composed of an acrylic pressure-sensitive adhesive and a polyimide base material, both of which are materials having a high moisture absorption rate. Since the grinding process and the etching process are processes using water, the protective film of the present invention is in a moisture-absorbing state.
When the moisture-absorbing protective film is heated in the heating step (C), floating may occur due to rapid expansion of moisture absorbed. In order to suppress this, it is preferable to use an oven or the like and preheat and dry the semiconductor wafer to which the protective film of the present invention is attached at 60 ° C. or higher and 100 ° C. or lower for several minutes to several tens of minutes.
－（Ｃ）加熱工程－
　本発明における（Ｃ）加熱工程では、本発明の保護フィルムが貼付され、回路非形成面が研削された半導体ウェハを１２０℃以上１８０℃以下の温度で加熱する。なお、本工程は、減圧下或いは加圧下で実施してもよいが、減圧下で実施すると、過酸化物の分解に伴う発生ガスによって浮きが発生しうるため、大気圧に近い圧力下で実施することが好ましく、汎用のオーブンが使用できる面から、大気圧下で行われることがより好ましい。
　この（Ｃ）加熱工程により、本発明の保護フィルムの粘着層が熱硬化する。
　この（Ｃ）加熱工程により、濡れ、凹凸追従に優れた粘着層の粘着が昂進して剥離不能になることを防ぐことができる。
　また、特定熱ラジカル発生剤（ｂ）の分解により発生したガスにより保護フィルムの浮きを抑制するためにも、特定熱ラジカル発生剤（ｂ）の分解は本工程にて完了していることが好ましい。
　このような点から、（Ｃ）加熱工程における加熱条件は、使用した特定熱ラジカル発生剤（ｂ）の１分間半減期温度に応じて設定されればよく、例えば、特定熱ラジカル発生剤（ｂ）の１分間半減期温度に対し、好ましくは±３０℃以内（より好ましくは±２０℃以内）で行うのがよい。
　（Ｃ）加熱工程の条件として、具体的には、大気圧下にて、１２０℃以上１８０℃以下（好ましくは１３０℃以上１７０℃以下）の温度で、数分以上１時間以下（好ましくは１分～１時間、より好ましくは３分～３０分、更に好ましく５分～３０分、特に好ましくは１０分～３０分）の加熱を行うことが好ましい。 -(C) Heating process-
In the heating step (C) in the present invention, the semiconductor wafer to which the protective film of the present invention is attached and the non-circuit-formed surface is ground is heated at a temperature of 120 ° C. or higher and 180 ° C. or lower. This step may be carried out under reduced pressure or under increased pressure, but if it is carried out under reduced pressure, floating may occur due to the generated gas accompanying decomposition of the peroxide. It is preferable to carry out at atmospheric pressure from the viewpoint that a general-purpose oven can be used.
By this (C) heating step, the adhesive layer of the protective film of the present invention is thermally cured.
By this (C) heating step, it is possible to prevent the adhesion of the pressure-sensitive adhesive layer excellent in wetting and unevenness tracking from being promoted and becoming inseparable.
Moreover, it is preferable that the decomposition of the specific heat radical generator (b) is completed in this step in order to suppress the floating of the protective film by the gas generated by the decomposition of the specific heat radical generator (b). .
From such a point, the heating conditions in the (C) heating step may be set according to the 1-minute half-life temperature of the used specific thermal radical generator (b). For example, the specific thermal radical generator (b ), Preferably within ± 30 ° C. (more preferably within ± 20 ° C.).
(C) Specifically, the heating step is performed at a temperature of 120 ° C. or higher and 180 ° C. or lower (preferably 130 ° C. or higher and 170 ° C. or lower) at atmospheric pressure, and several minutes or longer and 1 hour or shorter (preferably 1). It is preferable to carry out heating for a period of 1 minute to 1 hour, more preferably 3 minutes to 30 minutes, still more preferably 5 minutes to 30 minutes, particularly preferably 10 minutes to 30 minutes.
－（Ｄ）静置工程、及び、（Ｅ）真空加熱下での処理工程－
　本発明における（Ｄ）静置工程では、（Ｃ）の加熱工程後、本発明の保護フィルムが貼付された半導体ウェハを真空下に静置する。
　また、（Ｅ）真空加熱下での処理工程では、（Ｄ）静置工程後、真空且つ２００℃以上の条件下で、保護フィルムが貼付された半導体ウェハにおける回路非形成面に対し、金属蒸着、金属スパッタ、及びイオン注入のいずれか１の処理を施す。 -(D) Standing step and (E) Processing step under vacuum heating-
In the (D) standing step in the present invention, after the heating step (C), the semiconductor wafer to which the protective film of the present invention is stuck is left under vacuum.
Further, (E) in the treatment step under vacuum heating, (D) after the standing step, the metal is deposited on the non-circuit-formed surface of the semiconductor wafer to which the protective film is attached under vacuum and at 200 ° C. or higher. , Any one of metal sputtering and ion implantation is performed.
　（Ｅ）真空加熱下での処理工程において、金属蒸着には真空蒸着装置が、金属スパッタにはスパッタ装置が、イオン注入にはイオン注入装置がそれぞれ適用されるが、これらの装置はいずれも公知の真空装置である。
　これらの真空装置では、一般に、予備排気室に半導体ウェハを静置させ、ここである程度の真空度（例えば１Ｐａ以下）に到達してから、本装置に半導体ウェハを移す。かかる予備排気室での静置が、上記した（Ｄ）静置工程となる。そして、本装置において、真空下での金属蒸着、金属スパッタ、又はイオン注入の処理が行われるが、その際の装置内の半導体ウェハは、２００℃以上に加熱される。なお、（Ｅ）真空加熱下での処理工程における加熱の上限は、その処理の種類や、装置の加温・冷却機構などにより決定されるが、具体的には、３００℃程度である。 (E) In the treatment process under vacuum heating, a vacuum deposition apparatus is applied to metal deposition, a sputtering apparatus is applied to metal sputtering, and an ion implantation apparatus is applied to ion implantation. Vacuum equipment.
In these vacuum apparatuses, generally, a semiconductor wafer is allowed to stand in a preliminary exhaust chamber, and after reaching a certain degree of vacuum (for example, 1 Pa or less), the semiconductor wafer is transferred to this apparatus. The standing in the preliminary exhaust chamber is the above-described (D) standing step. In this apparatus, metal vapor deposition, metal sputtering, or ion implantation is performed under vacuum, and the semiconductor wafer in the apparatus at that time is heated to 200 ° C. or higher. In addition, although the upper limit of the heating in the processing step (E) under vacuum heating is determined by the type of the processing, the heating / cooling mechanism of the apparatus, etc., specifically, it is about 300 ° C.
－（Ｆ）剥離工程－
　本発明における（Ｆ）剥離工程では、（Ｅ）真空加熱下での処理工程後、本発明の保護フィルムを半導体ウェハから剥離する。
　本発明の保護フィルムをウェハ表面から剥離する操作は、人手により行われる場合もあるが、一般には、自動剥がし機と称される装置を用いて行われる。このような自動剥がし機としては、タカトリ（株）製、形式：ＡＴＲＭ－２０００Ｂ、同ＡＴＲＭ－２１００、帝国精機（株）製、形式：ＳＴＰシリーズ、日東精機（株）製、形式：ＨＲ－８５００ＩＩ等がある。また、前記の自動剥がし機によりウェハ表面から本発明の保護フィルムを剥離する際に用いられる剥がしテープと呼ばれる粘着テープとしては、例えば、住友スリーエム（株）製、ハイランド印フィラメントテープＮｏ．８９７等を用いることができる。 -(F) Peeling process-
In the (F) peeling process in the present invention, (E) the protective film of the present invention is peeled from the semiconductor wafer after the treatment process under vacuum heating.
Although the operation of peeling the protective film of the present invention from the wafer surface may be performed manually, it is generally performed using an apparatus called an automatic peeling machine. As such an automatic peeling machine, Takatori Co., Ltd., model: ATRM-2000B, ATRM-2100, Teikoku Seiki Co., Ltd., model: STP series, Nitto Seiki Co., Ltd., model: HR-8500II Etc. Moreover, as an adhesive tape called a peeling tape used when peeling the protective film of the present invention from the wafer surface by the automatic peeling machine, for example, Sumitomo 3M Co., Ltd., Highland Mark Filament Tape No. 897 or the like can be used.
　本発明の保護フィルムをウェハ表面から剥離する際の温度は、通常、２５℃前後の室温において行われるが、前記した自動剥がし機にウェハを昇温する機能が備わっている場合には、半導体ウェハを所定の温度（通常、４０℃～９０℃程度）まで昇温した状態で保護フィルムを剥離してもよい。 The temperature at which the protective film of the present invention is peeled off from the wafer surface is usually performed at room temperature of about 25 ° C. However, when the above-described automatic peeling machine has a function of heating the wafer, the semiconductor wafer The protective film may be peeled off while the temperature is raised to a predetermined temperature (usually about 40 ° C. to 90 ° C.).
　本発明の保護フィルムを剥離した後のウェハ表面は、必要に応じて洗浄される。洗浄方法としては、水洗浄、溶剤洗浄等の湿式洗浄、プラズマ洗浄等の乾式洗浄等が挙げられる。湿式洗浄の場合、超音波洗浄を併用してもよい。これらの洗浄方法は、ウェハ表面の汚染状況により適宜選択される。 The wafer surface after peeling off the protective film of the present invention is cleaned as necessary. Examples of the cleaning method include wet cleaning such as water cleaning and solvent cleaning, and dry cleaning such as plasma cleaning. In the case of wet cleaning, ultrasonic cleaning may be used in combination. These cleaning methods are appropriately selected depending on the contamination state of the wafer surface.
　本発明の半導体装置の製造方法においては、更に以下のような工程を含むことが好ましい。 The semiconductor device manufacturing method of the present invention preferably further includes the following steps.
　即ち、ポリイミド基材は硬質であり、粘着層の厚みが薄い場合、ウェハ表面の凹凸を吸収できないことがある。この場合、（Ｂ）研削工程での研削時に凸部裏面が過剰に研削されることがある。
　これを防止する点から、本発明の保護フィルムにおけるポリイミド基材の表面（粘着層の非形成面）に、公知の半導体ウェハ研削用フィルムを貼付する方法が採用される。
　半導体ウェハ研削用フィルムを貼付する方法としては、（Ｂ）研削工程の前に、半導体ウェハに貼付している保護フィルムのポリイミド基材の表面に、半導体ウェハ研削用フィルムを貼付する工程（（ｉ）工程）を行う方法、又は、（Ａ）貼付工程に、保護フィルムのポリイミド基材の表面に予め半導体ウェハ研削用フィルムを貼付してなるものを適用する方法が挙げられる。
　ここで用いられる半導体ウェハ研削用フィルムとしては、ウェハ表面の凹凸を吸収する軟質/応力緩和層を含んでいるものが好ましい。
　なお、半導体ウェハ研削用フィルムは、（Ｂ）研削工程の後であって（Ｃ）加熱工程の前に、本発明の保護フィルムから剥離されることが好ましい（（ii）工程）。 That is, the polyimide base material is hard, and when the thickness of the adhesive layer is thin, the unevenness on the wafer surface may not be absorbed. In this case, the back surface of the convex portion may be excessively ground during grinding in the (B) grinding step.
From the standpoint of preventing this, a method of applying a known semiconductor wafer grinding film to the surface of the polyimide base material (non-adhesive surface of the adhesive layer) in the protective film of the present invention is employed.
As a method of applying the semiconductor wafer grinding film, (B) the step of attaching the semiconductor wafer grinding film to the surface of the polyimide base material of the protective film applied to the semiconductor wafer ((i) )) Or a method of applying a semiconductor wafer grinding film in advance to the surface of the polyimide base material of the protective film.
The semiconductor wafer grinding film used here preferably includes a soft / stress relaxation layer that absorbs irregularities on the wafer surface.
The semiconductor wafer grinding film is preferably peeled off from the protective film of the present invention after the (B) grinding step and before the (C) heating step ((ii) step).
　（Ｂ）研削工程にて研削され、薄膜化した半導体ウェハは、反ったり、破損したりし易い。このことから、薄膜化した半導体ウェハの反りを抑制し、強度を高める点から、（Ｂ）研削工程が、半導体ウェハにおける回路非形成面の外周縁部を残し、内周部を研削する工程であることが好ましい。つまり、（Ｂ）研削工程では、半導体ウェハの外周縁部を厚く残し、強度を高める一方、中央部は所定厚みに研削する手法、いわゆるタイコプロセスを採用することが好ましい。
　本発明の保護フィルムにおけるポリイミド基材は、熱膨張は生じないものではなく、また、シリコンウェハとの熱膨張率が完全に一致するものでもない。そのため、より厳しい反りの制御が求められる局面（例えば半導体ウェハの更なる薄膜化や、高温に供される場合）では、本発明の保護フィルムを適用したまま、上記のようなタイコプロセスを併用して、半導体ウェハの反りの発生を抑制することが好ましい。これにより、反りによる搬送不良等が生じ難くなる。 (B) A semiconductor wafer that has been ground and thinned in a grinding step is likely to warp or break. From this point, in order to suppress warpage of the thinned semiconductor wafer and increase the strength, (B) the grinding step is a step of grinding the inner peripheral portion while leaving the outer peripheral portion of the circuit non-formed surface in the semiconductor wafer. Preferably there is. That is, in the (B) grinding step, it is preferable to use a so-called Tyco process, in which the outer peripheral edge of the semiconductor wafer is left thick and the strength is increased while the center is ground to a predetermined thickness.
The polyimide base material in the protective film of the present invention does not cause thermal expansion and does not completely match the thermal expansion coefficient with the silicon wafer. Therefore, in situations where more severe warpage control is required (for example, when the semiconductor wafer is further thinned or subjected to high temperatures), the above-described Tyco process is used in combination with the protective film of the present invention applied. Thus, it is preferable to suppress the occurrence of warpage of the semiconductor wafer. This makes it difficult for a conveyance failure or the like due to warpage to occur.
　本発明の半導体装置の製造方法が適用できる半導体ウェハとしては、シリコンウェハに限らず、窒化ガリウム、ゲルマニウム、ガリウム－ヒ素、ガリウム－リン、ガリウム－ヒ素－アルミニウムなどの半導体ウェハが挙げられる。 Semiconductor wafers to which the method for manufacturing a semiconductor device of the present invention can be applied are not limited to silicon wafers, but include semiconductor wafers such as gallium nitride, germanium, gallium-arsenic, gallium-phosphorus, and gallium-arsenic-aluminum.
　以下、実施例を示して本発明について更に詳細を説明する。 Hereinafter, the present invention will be described in more detail with reference to examples.
〔粘着層形成用塗布液の調製〕
　下記表２に記載の各成分を表２に記載の配合量（括弧内に記載）で使用し混合攪拌して、粘着層形成用塗布液１～１０を調製した。
　ここで、表２中、配合量は、アクリル系重合体中の単量体１００質量部に対する質量部であり、固形分の質量比である。 (Preparation of adhesive layer forming coating solution)
The components shown in Table 2 below were used in the amounts shown in Table 2 (described in parentheses) and mixed and stirred to prepare coating solutions 1 to 10 for forming an adhesive layer.
Here, in Table 2, a compounding quantity is a mass part with respect to 100 mass parts of monomers in an acrylic polymer, and is a mass ratio of solid content.
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　表２中にて略記された重合体１及び２、オリゴマー１及び２、過酸化物１～５、架橋剤１は以下のものである。
・重合体１：アクリル酸エチル８２部、メタクリル酸メチル１０部、アクリル酸ヒドロキシブチル８部及び重合開始剤としてベンゾイルパーオキサイド０．５質量部を混合し、トルエン６５質量部、酢酸エチル５０質量部が入った窒素置換フラスコ中に撹拌しながら８０℃で５時間かけて滴下し、更に５時間撹拌して反応させ、アクリル酸エステル共重合体溶液を得た。これを重合体１とした。
・重合体２：アクリル酸エチル４８質量部、アクリル酸－２－エチルヘキシル２７質量部、アクリル酸メチル２０質量部、メタクリル酸グリシジル５質量部、及び重合開始剤としてベンゾイルパーオキサイド０．５質量部を混合し、トルエン６５質量部、酢酸エチル５０質量部が入った窒素置換フラスコ中に撹拌しながら８０℃で５時間かけて滴下し、更に５時間撹拌して反応させた。反応終了後、冷却し、これにキシレン２５質量部、アクリル酸２．５質量部、及びテトラデシルベンジルアンモニウムクロライド１．５質量部を加え、空気を吹き込みながら８０℃で１０時間反応させ、重合性炭素－炭素二重結合が導入されたアクリル酸エステル共重合体溶液を得た。これを重合体２とした。 Polymers 1 and 2, oligomers 1 and 2, peroxides 1 to 5, and crosslinking agent 1 abbreviated in Table 2 are as follows.
Polymer 1: 82 parts of ethyl acrylate, 10 parts of methyl methacrylate, 8 parts of hydroxybutyl acrylate and 0.5 parts by weight of benzoyl peroxide as a polymerization initiator are mixed, 65 parts by weight of toluene, 50 parts by weight of ethyl acetate Was added dropwise at 80 ° C. over 5 hours while stirring in a nitrogen-substituted flask containing, and the reaction was further stirred for 5 hours to obtain an acrylate copolymer solution. This was designated as Polymer 1.
Polymer 2: 48 parts by mass of ethyl acrylate, 27 parts by mass of 2-ethylhexyl acrylate, 20 parts by mass of methyl acrylate, 5 parts by mass of glycidyl methacrylate, and 0.5 parts by mass of benzoyl peroxide as a polymerization initiator The mixture was added dropwise to a nitrogen-substituted flask containing 65 parts by mass of toluene and 50 parts by mass of ethyl acetate with stirring at 80 ° C. over 5 hours, and further stirred for 5 hours to be reacted. After completion of the reaction, the mixture was cooled, 25 parts by mass of xylene, 2.5 parts by mass of acrylic acid, and 1.5 parts by mass of tetradecylbenzylammonium chloride were added and reacted at 80 ° C. for 10 hours while blowing air. An acrylate copolymer solution having a carbon-carbon double bond introduced therein was obtained. This was designated as Polymer 2.
・オリゴマー１：ＡＤ－ＴＭＰ（新中村化学製、ジトリメチロールプロパンテトラアクリレート）
・オリゴマー２：アロニクス　Ｍ－４０２（東亞合成製、ジペンタエリスリトールペンタ及びヘキサアクリレート）
・過酸化物１：パーテトラＡ（日油製、2,2-Di(4,4-di-(t-butylperoxy)cyclohexyl)propane、分子量５６１、１分間半減期温度１５４℃）
・過酸化物２：ナイパーＢＭＴ（日油製、１分間半減期温度１３１℃）
・過酸化物３：パーロイルＴＣＰ（日油製、分子量３９９、１分間半減期温度９２℃）
・過酸化物４：パーブチルＣ（日油製、t-Butyl cumyl peroxide、分子量２０８、１分間半減期温度１７３℃）
・過酸化物５：パークミルＰ（日油製、分子量１９４、１分間半減期温度２３３℃）
・架橋剤１：オレスターＰ４９－７５Ｓ（三井化学製） ・ Oligomer 1: AD-TMP (manufactured by Shin-Nakamura Chemical, ditrimethylolpropane tetraacrylate)
・ Oligomer 2: Allonics M-402 (Toagosei, dipentaerythritol pentaacrylate and hexaacrylate)
・ Peroxide 1: Pertetra A (manufactured by NOF, 2,2-Di (4,4-di- (t-butylperoxy) cyclohexyl) propane, molecular weight 561, 1 minute half-life temperature 154 ° C.)
・ Peroxide 2: Niper BMT (manufactured by NOF, 1 minute half-life temperature 131 ° C)
Peroxide 3: Parroyl TCP (manufactured by NOF, molecular weight 399, half-life temperature 92 ° C. for 1 minute)
Peroxide 4: Perbutyl C (manufactured by NOF, t-Butyl cumyl peroxide, molecular weight 208, 1 minute half-life temperature 173 ° C.)
Peroxide 5: Parkmill P (manufactured by NOF, molecular weight 194, 1 minute half-life temperature 233 ° C.)
・ Crosslinking agent 1: Olester P49-75S (Mitsui Chemicals)
〔保護フィルムの作製〕
　３８μｍ厚みのポリイミドフィルム（東レデュポン社製カプトン１５０ＥＮ－Ａ）に、乾燥厚みが３０μｍになるように、表２に記載の粘着層形成用塗布液を塗布し、１００℃６分条件で乾燥して、実施例１～４及び比較例１～６の保護フィルムを作製した。
　その後、４０℃７日熟成で、架橋剤をアクリル系重合体と反応させた。 [Production of protective film]
To a 38 μm-thick polyimide film (Kapton 150EN-A manufactured by Toray DuPont Co., Ltd.), the adhesive layer forming coating solution shown in Table 2 was applied so that the dry thickness was 30 μm, and dried at 100 ° C. for 6 minutes. The protective films of Examples 1 to 4 and Comparative Examples 1 to 6 were produced.
Thereafter, the cross-linking agent was reacted with an acrylic polymer at 40 ° C. for 7 days.
〔粘着テープの評価〕
　各保護フィルムを、６インチのシリコンウェハの鏡面に貼り付けた後、これをオーブンにて８０℃で１０分加熱（予備加熱）し、続いて、表２に記載の条件で加熱して粘着層を熱硬化させた（比較例４、５は加熱なし）。その後、保護フィルムを貼付したシリコンウェハを真空オーブンに投入して真空下に置いた後、２５０℃で３０分間加熱した。オーブン内で保護フィルムの浮きの発生の有無を目視にて確認した。
　真空加熱後、室温に戻してから保護フィルムをシリコンウェハから剥離し、シリコンウェハ上に粘着層の残存（のり残り）がないか目視にて確認した。
　評価指標は以下の通りである。結果を表２に示す。 [Evaluation of adhesive tape]
After each protective film was attached to the mirror surface of a 6-inch silicon wafer, it was heated in an oven at 80 ° C. for 10 minutes (preliminary heating), and then heated under the conditions described in Table 2 to form an adhesive layer. Was heat-cured (Comparative Examples 4 and 5 were not heated). Then, after putting the silicon wafer which stuck the protective film into a vacuum oven and putting it under vacuum, it heated at 250 degreeC for 30 minutes. Whether or not the protective film was lifted in the oven was visually confirmed.
After returning to room temperature after vacuum heating, the protective film was peeled off from the silicon wafer, and it was visually confirmed whether or not the adhesive layer remained on the silicon wafer.
The evaluation index is as follows. The results are shown in Table 2.
　表２から明らかなように、実施例１～４の保護フィルムは、本発明におけるアクリル系重合体（ａ）、特定熱ラジカル発生剤（ｂ）、架橋剤（ｃ）、及び２官能以上のアクリル系オリゴマー（ｄ）を含む塗布液から得られた粘着層を有していることから、熱硬化後に真空加熱に供しても、保護フィルムの浮きが生じず、また、のり残りも生じていないことが分かる。 As is apparent from Table 2, the protective films of Examples 1 to 4 were prepared from the acrylic polymer (a), the specific thermal radical generator (b), the crosslinking agent (c), and the bifunctional or higher acrylic in the present invention. Because it has a pressure-sensitive adhesive layer obtained from a coating solution containing an oligomer (d), the protective film does not float even when subjected to vacuum heating after thermosetting, and no residue remains I understand.
〔実施例Ａ～Ｄ、比較例ａ～ｆ、及び参考例〕
　実施例１～４及び比較例１～６の保護フィルムを用い、以下のようにして予備加熱、粘着層の熱硬化、及び真空加熱を行った。
　実施例Ａ：実施例１の保護フィルムを６インチのシリコンウェハの鏡面に貼り付けた後、これをオーブンにて８０℃で１０分加熱（予備加熱）し、続いてオーブンで１５０℃１５分加熱し、粘着層を熱硬化させた。続いて、これを真空オーブンに投入して真空下に置いた後、２５０℃で３０分間加熱した。
　なお、予備加熱及び粘着層の熱硬化の際の加熱は、大気圧下にて行った。
　実施例Ｂ～Ｄ、比較例ａ～ｆ、及び参考例：実施例Ａにおいて用いた保護フィルムを下記表３に記載の保護フィルムに変え、下記表３に記載の加熱を行った以外は、実施例Ａと同様にした。
　実施例Ａ～Ｄ、比較例ａ～ｆ、及び参考例における真空加熱の際、オーブン内で保護フィルムの浮きの発生の有無を目視にて確認した。
　また、真空加熱後、室温に戻してから保護フィルムをシリコンウェハから剥離し、シリコンウェハ上に粘着層の残存（のり残り）がないか目視にて確認した。
　結果を表３に示す。 [Examples A to D, Comparative Examples a to f, and Reference Examples]
Using the protective films of Examples 1 to 4 and Comparative Examples 1 to 6, preheating, heat curing of the adhesive layer, and vacuum heating were performed as follows.
Example A: After the protective film of Example 1 was attached to the mirror surface of a 6-inch silicon wafer, this was heated in an oven at 80 ° C. for 10 minutes (preliminary heating), and then heated in an oven at 150 ° C. for 15 minutes. Then, the adhesive layer was thermally cured. Subsequently, this was put into a vacuum oven and placed under vacuum, and then heated at 250 ° C. for 30 minutes.
Note that the preheating and the heating during the thermosetting of the adhesive layer were performed under atmospheric pressure.
Examples B to D, Comparative Examples a to f, and Reference Example: Except that the protective film used in Example A was replaced with the protective film described in Table 3 below, and the heating described in Table 3 was performed. Same as Example A.
When vacuum heating was performed in Examples A to D, Comparative Examples a to f, and Reference Examples, the presence or absence of occurrence of floating of the protective film was visually confirmed in the oven.
Moreover, after returning to room temperature after vacuum heating, the protective film was peeled from the silicon wafer, and it was visually confirmed whether or not the adhesive layer remained on the silicon wafer.
The results are shown in Table 3.
Figure JPOXMLDOC01-appb-T000003
 
Figure JPOXMLDOC01-appb-T000003
 
　表３に明らかなように、実施例１～４の保護フィルムを用い、予備加熱、１２０℃以上１８０℃以下の温度での粘着層の熱硬化、及び真空且つ２００℃以上の条件下での放置を行った実施例Ａ～Ｄは、保護フィルムの浮きが生じず、また、のり残りも生じていないことが分かる。
　比較例１～３の保護フィルムを用い、予備加熱、１２０℃以上１８０℃以下の温度での粘着層の熱硬化、及び真空且つ２００℃以上の条件下での放置を行った比較例ａ～ｃは、保護フィルムの浮きは生じなかったものの、のり残りが生じていることが分かった。
　これは、粘着層中に含まれる熱ラジカル発生剤の１分間半減期温度が１４０℃未満である（比較例１、２）、又は、熱ラジカル発生剤を用いていないことに起因する（比較例３）。熱ラジカル発生剤の１分間半減期温度が１４０℃未満であることにより、粘着層の乾燥段階で熱ラジカル発生剤が分解又は揮発してしまい、粘着層の熱硬化が不十分であったと推測される。また、熱ラジカル発生剤を用いていない場合も同様に、粘着層の熱硬化が不十分であったと推測される。この結果、熱硬化が十分に進んでいないのにもかかわらず、粘着層が真空加熱にて急激に高温にされたため、粘着性が昂進してしまい、のり残りが生じたものと推測される。
　比較例４の保護フィルムを用い、予備加熱の後、粘着層の熱硬化を行わず、真空且つ２００℃以上の条件下での放置を行った比較例ｄは、のり残りは生じなかったものの、保護フィルムの浮きが生じた。これは、架橋剤を多めに添加した塗布液を用いていることから、硬質な粘着層となっており、シリコンウェハに対する濡れ性が低く、真空加熱時にシリコンウェハに対する接着を維持できなかったことによるものと推測される。
　比較例５の保護フィルムを用い、予備加熱の後、粘着層の熱硬化を行わず、真空且つ２００℃以上の条件下での放置を行った比較例ｅは、保護フィルムの浮きは生じなかったものの、のり残りが生じていることが分かった。これは、架橋剤を少なめに添加した塗布液を用いていることから、軟質な粘着層となっており、シリコンウェハに対する濡れ性に優れ、真空加熱下でもシリコンウェハに対する接着を維持できたが、高温にされたため、粘着性が昂進してしまい、のり残りが生じたものと推測される。
　参考例によれば、実施例１の保護フィルムを用いていても、熱硬化の工程を経ていないと、のり残りは生じなかったものの、保護フィルムの浮きが生じることが分かった。これは、真空加熱下にて、特定熱ラジカル発生剤（過酸化物）の分解に伴うガス成分が浮きの発生の引き金になったと推定される。 As is apparent from Table 3, using the protective films of Examples 1 to 4, preheating, thermosetting the adhesive layer at a temperature of 120 ° C. or higher and 180 ° C. or lower, and leaving it in a vacuum at 200 ° C. or higher. It can be seen that in Examples A to D where the test was carried out, the protective film was not lifted and no residue remained.
Comparative Examples a to c using the protective films of Comparative Examples 1 to 3, which were preheated, thermally cured the adhesive layer at a temperature of 120 ° C. to 180 ° C., and allowed to stand in a vacuum at 200 ° C. or higher. It was found that although the protective film did not float, there was a residue.
This is because the one-minute half-life temperature of the thermal radical generator contained in the adhesive layer is less than 140 ° C. (Comparative Examples 1 and 2), or no thermal radical generator is used (Comparative Example). 3). It is speculated that the thermal radical generator decomposes or volatilizes in the drying stage of the adhesive layer due to the 1-minute half-life temperature of the thermal radical generator being less than 140 ° C., and the thermosetting of the adhesive layer is insufficient. The Similarly, when the thermal radical generator is not used, it is presumed that the thermosetting of the adhesive layer was insufficient. As a result, it is presumed that the adhesive layer was suddenly heated to a high temperature by vacuum heating despite the fact that the thermosetting was not sufficiently advanced, so that the adhesiveness increased and a residue was generated.
Comparative Example d using the protective film of Comparative Example 4, after preheating, without performing the thermosetting of the adhesive layer and leaving it under vacuum and at 200 ° C. or higher, did not cause a residue, The protective film was lifted. This is because a coating solution containing a large amount of a crosslinking agent is used, so that it is a hard adhesive layer, has low wettability with respect to the silicon wafer, and was unable to maintain adhesion to the silicon wafer during vacuum heating. Presumed to be.
In Comparative Example e, in which the protective film of Comparative Example 5 was used, and after the preliminary heating, the adhesive layer was not thermally cured, and was left in a vacuum at 200 ° C. or higher, the protective film did not float. However, it was found that there was a residue. This is because it uses a coating solution with a small amount of crosslinking agent added, it is a soft adhesive layer, excellent wettability to the silicon wafer, and was able to maintain adhesion to the silicon wafer even under vacuum heating, It is presumed that the adhesiveness has increased due to the high temperature, and the residue remains.
According to the reference example, even if the protective film of Example 1 was used, it was found that if the heat curing process was not performed, no residue remained, but the protective film floated. This is presumed that the gas component accompanying the decomposition of the specific thermal radical generator (peroxide) triggered the generation of floating under vacuum heating.
〔実施例Ｅ〕
　実施例１の保護フィルムを、８インチシリコンウェハ（ミラー）の鏡面に貼り付けた（（Ａ）貼付工程）。
　続いて、ディスコ社製のバックグラインダーを用い、ウェハ裏面を厚みが１００μｍになるまで研削した（（Ｂ）研削工程）。
　研削後、ウェハに割れはなく、反りも１ｍｍ以下であった。
　次いで、このウェハをオーブンにて８０℃で１０分乾燥し（予備加熱）、更に続いて、１５０℃１５分オーブンで加熱し粘着層を硬化した（（Ｃ）加熱工程）。なお、予備加熱及び粘着層の熱硬化の際の加熱は、大気圧下にて行った。
　粘着層を硬化した後、ウェハの反りは２ｍｍ程度で、ウェハの搬送装置で扱える範囲の反り量であった。
　続いて、このウェハを真空オーブンに投入して真空下に置いた後、２５０℃で３０分加熱したところ、かかる真空オーブンにて浮きは発生しなかった。
　その後、大気圧、室温の環境下にもどしたウェハから、実施例１の保護フィルムをウェハから剥離したところ、ウェハ表面にのり残りは見られなかった。 Example E
The protective film of Example 1 was affixed to the mirror surface of an 8-inch silicon wafer (mirror) ((A) affixing process).
Subsequently, the back surface of the wafer was ground to a thickness of 100 μm using a disco back grinder ((B) grinding step).
After grinding, the wafer was not cracked and warpage was 1 mm or less.
Next, the wafer was dried in an oven at 80 ° C. for 10 minutes (preliminary heating), and then further heated in an oven at 150 ° C. for 15 minutes to cure the adhesive layer ((C) heating step). Note that the preheating and the heating during the thermosetting of the adhesive layer were performed under atmospheric pressure.
After the adhesive layer was cured, the warpage of the wafer was about 2 mm, which was the amount of warpage that could be handled by the wafer transfer device.
Subsequently, the wafer was put into a vacuum oven and placed under vacuum, and then heated at 250 ° C. for 30 minutes. No floating occurred in the vacuum oven.
Thereafter, when the protective film of Example 1 was peeled off from the wafer returned to the atmospheric pressure and room temperature environment, no residue was observed on the wafer surface.
　２０１４年３月３１日に出願された日本出願２０１４－０７４４８９の開示は、その全体が参照により本明細書に取り込まれる。
　本明細書に記載された全ての文献、特許出願、および技術規格は、個々の文献、特許出願、および技術規格が参照により取り込まれることが具体的かつ個々に記された場合と同程度に、本明細書中に参照により取り込まれる。 The disclosure of Japanese application 2014-07489 filed on March 31, 2014 is incorporated herein by reference in its entirety.
All documents, patent applications, and technical standards mentioned in this specification are to the same extent as if each individual document, patent application, and technical standard were specifically and individually described to be incorporated by reference, Incorporated herein by reference.

Claims (10)

  1. 　ポリイミド基材と、
    　前記ポリイミド基材の片表面に設けられ、アクリル系重合体（ａ）、１分間半減期温度が１４０℃以上２００℃以下である熱ラジカル発生剤（ｂ）、及び架橋剤（ｃ）を含む組成物から得られた熱硬化性粘着層と、
    　を有し、半導体ウェハの回路形成面に貼付される保護フィルム。     A polyimide substrate;
    A composition comprising an acrylic polymer (a), a thermal radical generator (b) having a half-life temperature of 140 ° C. or more and 200 ° C. or less, and a crosslinking agent (c) provided on one surface of the polyimide substrate. A thermosetting adhesive layer obtained from the product,
    A protective film that is attached to a circuit forming surface of a semiconductor wafer.
  2. 　前記熱ラジカル発生剤（ｂ）の分子量が２００以上１０００以下である請求項１に記載の保護フィルム。 The protective film according to claim 1, wherein the thermal radical generator (b) has a molecular weight of 200 or more and 1000 or less.
  3. 　前記組成物が２官能以上のアクリル系オリゴマー（ｄ）を更に含む請求項１又は請求項２に記載の保護フィルム。 The protective film according to claim 1 or 2, wherein the composition further comprises a bifunctional or higher functional acrylic oligomer (d).
  4. 　前記アクリル系重合体（ａ）が側鎖にラジカル反応性の二重結合を有する重合体である請求項１～請求項３のいずれか１項に記載の保護フィルム。 The protective film according to any one of claims 1 to 3, wherein the acrylic polymer (a) is a polymer having a radical-reactive double bond in a side chain.
  5. 　（１）半導体ウェハの回路形成面に、熱硬化性粘着層を有する保護フィルムを当該回路形成面と当該熱硬化性粘着層が接するように貼付する貼付工程と、
    　（２）前記保護フィルムが貼付された前記半導体ウェハを１２０℃以上１８０℃以下の温度で加熱する加熱工程と、
    　（３）（２）の加熱工程後、前記保護フィルムが貼付された前記半導体ウェハを真空下に静置する静置工程と、
    　（４）（３）の静置工程後、真空且つ２００℃以上の条件下で、前記半導体ウェハにおける回路非形成面に対し、金属蒸着、金属スパッタ、及びイオン注入のいずれか１つの処理を施す処理工程と、
    　を含む半導体装置の製造方法における前記保護フィルムとして用いられる、請求項１～請求項４のいずれか１項に記載の保護フィルム。     (1) An attaching step of attaching a protective film having a thermosetting adhesive layer to a circuit forming surface of a semiconductor wafer so that the circuit forming surface and the thermosetting adhesive layer are in contact with each other;
    (2) a heating step of heating the semiconductor wafer to which the protective film is attached at a temperature of 120 ° C. or higher and 180 ° C. or lower;
    (3) After the heating step of (2), a standing step of standing the semiconductor wafer to which the protective film is attached under vacuum,
    (4) After the stationary step of (3), any one of metal vapor deposition, metal sputtering, and ion implantation is performed on the non-circuit-formed surface of the semiconductor wafer under vacuum and at 200 ° C. or higher. Processing steps;
    The protective film according to any one of claims 1 to 4, which is used as the protective film in a method for producing a semiconductor device comprising:
  6. 　（Ａ）半導体ウェハの回路形成面に、請求項１～請求項５のいずれか１項に記載の保護フィルムを、当該回路形成面に前記熱硬化性粘着層が接するように貼付する貼付工程と、
    　（Ｂ）前記半導体ウェハにおける回路非形成面を研削する研削工程と、
    　（Ｃ）前記保護フィルムが貼付され、回路非形成面が研削された前記半導体ウェハを１２０℃以上１８０℃以下の温度で加熱する加熱工程と、
    　（Ｄ）（Ｃ）の加熱工程後、前記保護フィルムが貼付された前記半導体ウェハを真空下に静置する静置工程と、
    　（Ｅ）（Ｄ）の静置工程後、真空且つ２００℃以上の条件下で、前記保護フィルムが貼付された前記半導体ウェハにおける回路非形成面に対し、金属蒸着、金属スパッタ、及びイオン注入のいずれか１つの処理を施す処理工程と、
    　（Ｆ）前記保護フィルムを前記半導体ウェハから剥離する剥離工程と、
    　を含む、半導体装置の製造方法。     (A) an attaching step of attaching the protective film according to any one of claims 1 to 5 to a circuit forming surface of a semiconductor wafer so that the thermosetting adhesive layer is in contact with the circuit forming surface; ,
    (B) a grinding step of grinding a non-circuit-formed surface of the semiconductor wafer;
    (C) a heating step of heating the semiconductor wafer to which the protective film is attached and the non-circuit-formed surface is ground at a temperature of 120 ° C. or higher and 180 ° C. or lower;
    (D) after the heating step of (C), a standing step of standing the semiconductor wafer to which the protective film is stuck under vacuum;
    (E) After the standing step of (D), under vacuum and at a temperature of 200 ° C. or higher, metal deposition, metal sputtering, and ion implantation are performed on the non-circuit-formed surface of the semiconductor wafer to which the protective film is attached. A processing step of applying any one of the processing;
    (F) a peeling step of peeling the protective film from the semiconductor wafer;
    A method for manufacturing a semiconductor device, comprising:
  7. 　前記（Ａ）の貼付工程の後で、且つ、前記（Ｂ）の研削工程の前に、
    　（ｉ）前記保護フィルムのポリイミド基材の表面に、半導体ウェハ研削用フィルムを貼付する工程を含む請求項６に記載の半導体装置の製造方法。     After the attaching step (A) and before the grinding step (B),
    (I) The manufacturing method of the semiconductor device of Claim 6 including the process of sticking the film for semiconductor wafer grinding on the surface of the polyimide base material of the said protective film.
  8. 　前記（Ａ）の貼付工程に用いられる前記保護フィルムが、該保護フィルムのポリイミド基材の表面に半導体ウェハ研削用フィルムを貼付してなる、請求項６に記載の半導体装置の製造方法。 The method for manufacturing a semiconductor device according to claim 6, wherein the protective film used in the attaching step (A) is obtained by attaching a semiconductor wafer grinding film to a surface of a polyimide base material of the protective film.
  9. 　前記（Ｂ）の研削工程の後で、且つ、前記（Ｃ）の加熱工程の前に、
    　（ii）前記半導体ウェハ研削用フィルムを前記保護フィルムから剥離する工程を含む請求項７又は請求項８に記載の半導体装置の製造方法。     After the grinding step (B) and before the heating step (C),
    (Ii) The method for manufacturing a semiconductor device according to claim 7 or 8, comprising a step of peeling the semiconductor wafer grinding film from the protective film.
  10. 　前記（Ｂ）の研削工程が、前記半導体ウェハにおける回路非形成面の外周縁部を残し、内周部を研削する工程である請求項６～請求項９のいずれか１項に記載の半導体装置の製造方法。 The semiconductor device according to any one of claims 6 to 9, wherein the grinding step (B) is a step of grinding an inner peripheral portion while leaving an outer peripheral portion of a non-circuit-formed surface of the semiconductor wafer. Manufacturing method.
PCT/JP2015/059459 2014-03-31 2015-03-26 Protective film, and production method for semiconductor device using protective film WO2015152010A1 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
JP2016511600A JP6106332B2 (en) 2014-03-31 2015-03-26 Protective film and method for manufacturing semiconductor device using the protective film
CN201580007736.4A CN105981137B (en) 2014-03-31 2015-03-26 The manufacturing method of the semiconductor device of protective film and the use protective film

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2014-074489 2014-03-31
JP2014074489 2014-03-31

Publications (1)

Publication Number Publication Date
WO2015152010A1 true WO2015152010A1 (en) 2015-10-08

Family

ID=54240336

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2015/059459 WO2015152010A1 (en) 2014-03-31 2015-03-26 Protective film, and production method for semiconductor device using protective film

Country Status (4)

Country Link
JP (1) JP6106332B2 (en)
CN (1) CN105981137B (en)
TW (1) TWI673313B (en)
WO (1) WO2015152010A1 (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2017013479A1 (en) * 2015-07-17 2017-01-26 藤森工業株式会社 Adhesive resin layer and adhesive resin film
JP2018133505A (en) * 2017-02-17 2018-08-23 株式会社ディスコ Plasma etching method
JPWO2022030604A1 (en) * 2020-08-07 2022-02-10

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109082241A (en) * 2017-06-13 2018-12-25 麦克赛尔控股株式会社 The laminated body of double-sided adhesive tape and thin film component and bearing part
JP6777233B2 (en) * 2017-07-12 2020-10-28 富士電機株式会社 Manufacturing method of semiconductor devices
WO2020189568A1 (en) * 2019-03-15 2020-09-24 リンテック株式会社 Adhesive sheet and semiconductor device production method
JP6803498B1 (en) * 2019-03-29 2020-12-23 三井化学東セロ株式会社 Manufacturing method of electronic device

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2011204793A (en) * 2010-03-24 2011-10-13 Sekisui Chem Co Ltd Wafer processing method
JP2012144616A (en) * 2011-01-11 2012-08-02 Shin-Etsu Chemical Co Ltd Temporary adhesive composition, and method for manufacturing thin wafer
JP2013038327A (en) * 2011-08-10 2013-02-21 Fujitsu Semiconductor Ltd Substrate transfer system, semiconductor manufacturing system, and substrate transfer method
JP2014053623A (en) * 2012-08-07 2014-03-20 Sekisui Chem Co Ltd Processing method of wafer

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20050244631A1 (en) * 2004-04-28 2005-11-03 Mitsui Chemicals, Inc. Surface protecting film for semiconductor wafer and method of protecting semiconductor wafer using the same

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2011204793A (en) * 2010-03-24 2011-10-13 Sekisui Chem Co Ltd Wafer processing method
JP2012144616A (en) * 2011-01-11 2012-08-02 Shin-Etsu Chemical Co Ltd Temporary adhesive composition, and method for manufacturing thin wafer
JP2013038327A (en) * 2011-08-10 2013-02-21 Fujitsu Semiconductor Ltd Substrate transfer system, semiconductor manufacturing system, and substrate transfer method
JP2014053623A (en) * 2012-08-07 2014-03-20 Sekisui Chem Co Ltd Processing method of wafer

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2017013479A1 (en) * 2015-07-17 2017-01-26 藤森工業株式会社 Adhesive resin layer and adhesive resin film
JP2017025152A (en) * 2015-07-17 2017-02-02 藤森工業株式会社 Adhesive resin layer and adhesive resin film
US10544333B2 (en) 2015-07-17 2020-01-28 Fujimori Kogyo Co., Ltd. Adhesive resin layer and adhesive resin film
JP2018133505A (en) * 2017-02-17 2018-08-23 株式会社ディスコ Plasma etching method
CN108461397A (en) * 2017-02-17 2018-08-28 株式会社迪思科 Plasma etching method
CN108461397B (en) * 2017-02-17 2023-09-19 株式会社迪思科 Plasma etching method
JPWO2022030604A1 (en) * 2020-08-07 2022-02-10
WO2022030604A1 (en) * 2020-08-07 2022-02-10 日東電工株式会社 Protective cover member and member-supplying sheet
JP7247419B2 (en) 2020-08-07 2023-03-28 日東電工株式会社 Protective cover member and member supply sheet
US12060263B2 (en) 2020-08-07 2024-08-13 Nitto Denko Corporation Protective cover member and member supplying sheet

Also Published As

Publication number Publication date
JPWO2015152010A1 (en) 2017-04-13
TWI673313B (en) 2019-10-01
CN105981137B (en) 2018-08-31
TW201546148A (en) 2015-12-16
JP6106332B2 (en) 2017-03-29
CN105981137A (en) 2016-09-28

Similar Documents

Publication Publication Date Title
JP6106332B2 (en) Protective film and method for manufacturing semiconductor device using the protective film
TWI413672B (en) Processing of processed materials
TWI398501B (en) Adhesive sheet for dicing and processing method of workpiece using the adhesive sheet
JP4781185B2 (en) Heat-resistant dicing tape or sheet
TWI693268B (en) Semiconductor wafer surface protective film and method of manufacturing semiconductor device
KR101849785B1 (en) Radiation-curable pressure-sensitive adhesive composition and pressure-sensitive adhesive sheet
JP5921927B2 (en) Heat release type adhesive sheet
JP5313837B2 (en) Removable adhesive sheet
TW201117279A (en) Adhesive sheet for supporting and protecting semiconductor wafer and method for grinding back of semiconductor wafer
JP2009064975A (en) Dicing adhesive sheet and dicing method
JP6775436B2 (en) Manufacturing method for film adhesives, semiconductor processing sheets and semiconductor devices
JP2009132867A (en) Double-sided self-adhesive sheet for processing plate-like member and method of processing plate-like member
TW202016234A (en) Semiconductor processing adhesive tape and method of manufacturing semiconductor device
JPWO2020003920A1 (en) Manufacturing method of adhesive tape for semiconductor processing and semiconductor devices
JP4054219B2 (en) Semiconductor wafer surface protecting adhesive film and semiconductor wafer protecting method using the adhesive film
TWI507502B (en) Semiconductor wafer processing adhesive sheet
KR101888198B1 (en) Radiation-curable pressure-sensitive adhesive composition and pressure-sensitive adhesive sheet
TW202130761A (en) Sheet for workpiece processing and method for manufacturing processed workpiece to provide a sheet for workpiece processing which has good operability and expandability even after heating
KR102642081B1 (en) Manufacturing method of adhesive tape and semiconductor device
JP2008001822A (en) Method for processing semiconductor wafer, adhesive film for processing the semiconductor wafer used for the same and method for producing the adhesive film
TW202031856A (en) Workpiece processing sheet
JP2005019759A (en) Adhesive film for protecting surface of semiconductor wafer and method for protecting semiconductor using this adhesive tape
JP2018207011A (en) Semiconductor chip manufacturing method and adhesive tape
JP7069116B2 (en) Base material for back grind tape
JP2019033214A (en) Manufacturing method of semiconductor device

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 15772838

Country of ref document: EP

Kind code of ref document: A1

ENP Entry into the national phase

Ref document number: 2016511600

Country of ref document: JP

Kind code of ref document: A

NENP Non-entry into the national phase
122 Ep: pct application non-entry in european phase

Ref document number: 15772838

Country of ref document: EP

Kind code of ref document: A1