WO2023281858A1 - Protective sheet for semiconductor processing, and semiconductor device manufacturing method - Google Patents

Protective sheet for semiconductor processing, and semiconductor device manufacturing method Download PDF

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Publication number
WO2023281858A1
WO2023281858A1 PCT/JP2022/014413 JP2022014413W WO2023281858A1 WO 2023281858 A1 WO2023281858 A1 WO 2023281858A1 JP 2022014413 W JP2022014413 W JP 2022014413W WO 2023281858 A1 WO2023281858 A1 WO 2023281858A1
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WO
WIPO (PCT)
Prior art keywords
wafer
adhesive layer
protective sheet
semiconductor processing
meth
Prior art date
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PCT/JP2022/014413
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French (fr)
Japanese (ja)
Inventor
和幸 田村
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リンテック株式会社
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Publication date
Application filed by リンテック株式会社 filed Critical リンテック株式会社
Priority to JP2023533422A priority Critical patent/JPWO2023281858A1/ja
Priority to KR1020237040009A priority patent/KR20240031948A/en
Priority to CN202280039266.XA priority patent/CN117413347A/en
Publication of WO2023281858A1 publication Critical patent/WO2023281858A1/en

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    • 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
    • C09J201/00—Adhesives based on unspecified macromolecular compounds
    • 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
    • C09J7/38—Pressure-sensitive adhesives [PSA]
    • 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
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer
    • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic System or AIIIBV compounds with or without impurities, e.g. doping materials
    • H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
    • 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
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer
    • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic System or AIIIBV compounds with or without impurities, e.g. doping materials
    • H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
    • H01L21/302—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to change their surface-physical characteristics or shape, e.g. etching, polishing, cutting
    • H01L21/304—Mechanical treatment, e.g. grinding, polishing, cutting
    • 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
    • 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
    • H01L21/70—Manufacture or treatment of devices consisting of a plurality of solid state components formed in or on a common substrate or of parts thereof; Manufacture of integrated circuit devices or of parts thereof
    • H01L21/77—Manufacture or treatment of devices consisting of a plurality of solid state components or integrated circuits formed in, or on, a common substrate
    • H01L21/78—Manufacture or treatment of devices consisting of a plurality of solid state components or integrated circuits formed in, or on, a common substrate with subsequent division of the substrate into plural individual devices
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J2203/00—Applications of adhesives in processes or use of adhesives in the form of films or foils
    • C09J2203/326—Applications of adhesives in processes or use of adhesives in the form of films or foils for bonding electronic components such as wafers, chips or semiconductors
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J2301/00—Additional features of adhesives in the form of films or foils
    • C09J2301/30—Additional features of adhesives in the form of films or foils characterized by the chemical, physicochemical or physical properties of the adhesive or the carrier
    • C09J2301/312—Additional features of adhesives in the form of films or foils characterized by the chemical, physicochemical or physical properties of the adhesive or the carrier parameters being the characterizing feature
    • 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

Definitions

  • the present invention relates to a protective sheet for semiconductor processing and a method for manufacturing a semiconductor device.
  • the present invention relates to a protective sheet for semiconductor processing suitably used in a method of grinding the backside of a wafer and singulating the wafer by the stress of the wafer, and a method of manufacturing a semiconductor device using the protective sheet for semiconductor processing.
  • DBG Densibling Before Grinding
  • the backside grinding of the wafer and the singulation of the wafer can be performed at the same time, so thin chips can be manufactured efficiently.
  • an adhesive tape called a backgrind sheet is attached to the wafer surface to protect the circuits on the wafer surface and to hold the semiconductor wafer and semiconductor chips. It is common to
  • Patent Documents 1 and 2 disclose an adhesive having a base material with a high Young's modulus and a buffer layer provided on one side of the base material and an adhesive layer provided on the other side of the base material.
  • a tape is disclosed.
  • LDBG Laser Dicing Before Grinding
  • the pressure during backgrinding concentrates on the adhering foreign matter, and the wafer may break starting from the foreign matter.
  • the wafer is likely to be damaged by a slight concentration of pressure. Therefore, it is necessary to suppress electrification that occurs during wafer processing.
  • the backgrinding tape strongly adheres to the surface of the wafer when the backside of the wafer is ground to sufficiently protect the circuits, etc., and when the backgrinding tape is peeled off from the wafer after the backside grinding, the backgrinding tape is easily peeled off from the wafer. is required. Therefore, the pressure-sensitive adhesive layer of the backgrinding tape applied to the wafer is usually composed of an energy ray-curable pressure-sensitive adhesive. At the time of peeling, the pressure-sensitive adhesive layer is irradiated with energy rays to be cured and reduced in adhesive strength, thereby achieving both adhesion during back-grinding and releasability after back-grinding.
  • the adhesive layer may remain on the wafer when peeled off, or chipping or breakage may occur due to contact between individualized chips due to poor peeling. (hereinafter also referred to as chip cracks) may occur. Especially in LDBG, since the kerf width of the chip is small, cracks may occur in the chip even with a slight peeling defect.
  • the present invention has been made in view of such circumstances, and even in the case where the wafer is processed to be thin by DBG or the like, the charging generated during processing of the wafer is sufficiently suppressed, and the cracking of the chip during separation is suppressed. It is an object of the present invention to provide a protective sheet for semiconductor processing that has a high degree of resistance, and to provide a method for manufacturing a semiconductor device using the protective sheet for semiconductor processing.
  • the protective sheet for semiconductor processing has a surface resistivity of 5.1 ⁇ 10 12 ⁇ /cm 2 or more and 1.0 ⁇ 10 15 ⁇ /cm 2 or less after curing with energy rays.
  • a protective sheet for semiconductor processing has an adhesive layer on one main surface of a base material, an antistatic layer is provided between the base material and the adhesive layer, and the other main surface of the base material A structure in which a buffer layer is provided on top, or a structure in which an adhesive layer is provided on one main surface of a substrate, and an antistatic layer and a buffer layer are provided between the substrate and the adhesive layer
  • the protective sheet for semiconductor processing according to any one of [1] to [4] having a structure.
  • [7] A step of attaching the protective sheet for semiconductor processing according to any one of [1] to [6] to the surface of the wafer; a step of forming a groove from the front surface side of the wafer, or a step of forming a modified region inside the wafer from the front surface or the rear surface of the wafer; a step of grinding a wafer having a protective sheet for semiconductor processing adhered to its surface and having grooves or modified regions formed thereon from the back side, and singulating the wafer into a plurality of chips starting from the grooves or modified regions; , and peeling off a protective sheet for semiconductor processing from individualized chips.
  • the protective sheet for semiconductor processing sufficiently suppresses electrification that occurs during wafer processing and suppresses chip cracking during peeling. and a method for manufacturing a semiconductor device using the protective sheet for semiconductor processing.
  • FIG. 1A is a schematic cross-sectional view showing an example of the protective sheet for semiconductor processing according to this embodiment.
  • FIG. 1B is a schematic cross-sectional view showing another example of the protective sheet for semiconductor processing according to this embodiment.
  • FIG. 2 is a schematic cross-sectional view showing how the protective sheet for semiconductor processing according to this embodiment is attached to the circuit surface of the wafer.
  • Wafer singulation refers to dividing the wafer into individual circuits to obtain chips.
  • the "front surface” of the wafer refers to the surface on which circuits, electrodes, etc. are formed, and the “back surface” of the wafer refers to the surface on which circuits, etc. are not formed.
  • DBG Downward Grinding
  • the grooves formed on the surface side of the wafer are formed by a method such as blade dicing, laser dicing or plasma dicing.
  • LDBG Laser Dicing Before Grinding
  • DBG Laser Dicing Before Grinding
  • Chip group refers to a plurality of chips held on the protective sheet for semiconductor processing according to the present embodiment after singulation of the wafer. These chips collectively form a shape similar to that of the wafer.
  • (Meth)acrylate is used as a term to indicate both "acrylate” and “methacrylate”, and the same applies to other similar terms.
  • Energy rays refer to ultraviolet rays, electron rays, etc., preferably ultraviolet rays.
  • Weight average molecular weight is a polystyrene conversion value measured by a gel permeation chromatography (GPC) method unless otherwise specified. Measurement by such a method can be carried out, for example, on a high-speed GPC apparatus "HLC-8120GPC” manufactured by Tosoh Corporation, using high-speed columns “TSK guard column H XL -H", “TSK Gel GMH XL “, and “TSK Gel G2000 H XL “. (all manufactured by Tosoh Corporation) in this order, column temperature: 40° C., liquid feed rate: 1.0 mL/min, and a differential refractometer as a detector.
  • GPC gel permeation chromatography
  • the protective sheet for semiconductor processing 1 has an antistatic layer 20 and an adhesive layer 30 provided in this order on one main surface 10a of a substrate 10. It has a configuration in which a buffer layer 40 is provided on the other main surface 10b. From the viewpoint of the antistatic function, the antistatic layer is preferably close to the peeling interface of the protective sheet for semiconductor processing, that is, the surface 30a of the pressure-sensitive adhesive layer. Therefore, as shown in FIG. 1A, antistatic layer 20 is preferably provided on one main surface 10a of substrate 10 rather than on the other main surface 10b of substrate 10. FIG. When the protective sheet for semiconductor processing 1 is used, the surface 30a of the pressure-sensitive adhesive layer 30 is temporarily attached to an adherend and then peeled off from the adherend.
  • the protective sheet for semiconductor processing is not limited to the configuration shown in FIG. 1A.
  • the protective sheet for semiconductor processing 1 may be provided with an antistatic layer 20, an adhesive layer 30 and a buffer layer 40 on one main surface 10a of the substrate 10.
  • FIG. The antistatic layer 20 and the buffer layer 40 are arranged between the substrate 10 and the adhesive layer 30 .
  • the buffer layer 40, the antistatic layer 20 and the adhesive layer 30 are arranged in this order on the substrate 10.
  • the protective sheet for semiconductor processing may have other layers as long as the effects of the present invention can be obtained. That is, as long as the protective sheet for semiconductor processing has a substrate, an antistatic layer, a buffer layer and an adhesive layer, other layers may be formed between the substrate and the buffer layer, for example. However, another layer may be formed between the substrate and the antistatic layer.
  • the surface 30a of the adhesive layer is attached to the circuit surface of the wafer 100 as an adherend, that is, the surface 100a of the wafer 100, whereby the protective sheet for semiconductor processing according to the present embodiment is formed. 1 protects the front surface 100a of the wafer 100 when the rear surface 100b of the wafer 100 is ground.
  • the protective sheet for semiconductor processing includes an antistatic layer and the pressure-sensitive adhesive layer has a surface resistivity within a predetermined range, thereby lowering the charged voltage and alleviating static electricity.
  • the surface resistivity of the pressure-sensitive adhesive layer reflects the degree of curing of the pressure-sensitive adhesive layer after irradiation with energy rays.
  • the pressure-sensitive adhesive layer cures more easily, and the number of cross-linking points in the pressure-sensitive adhesive layer after curing increases, so electric charges move. becomes difficult and the surface resistivity tends to increase.
  • the amount of energy ray-polymerizable carbon-carbon double bonds in the pressure-sensitive adhesive layer before curing decreases, the surface resistivity tends to decrease, but the number of starting points for the polymerization reaction decreases. Hardening tends to be insufficient.
  • the composition of the pressure-sensitive adhesive layer is sufficiently cured by energy ray irradiation.
  • the surface resistivity of the adhesive layer is controlled within a predetermined range to alleviate electrification and to suppress breakage, cracks, etc. of wafers and the like caused by poor peeling of the adhesive layer.
  • the substrate is not limited as long as it is made of a material that can support the wafer before the back surface of the wafer is ground and that can hold the wafer after the back surface is ground.
  • the base material includes various resin films used as base materials for back grind tapes.
  • the substrate may be composed of a single-layer film made of one resin film, or may be composed of a multi-layer film in which a plurality of resin films are laminated.
  • the substrate preferably has high rigidity.
  • the high rigidity of the base material makes it possible to suppress vibration and the like during back-grinding.
  • workability is improved when the protective sheet for semiconductor processing is attached to the wafer.
  • the Young's modulus of the substrate at 23° C. is preferably 1000 MPa or more, more preferably 1800 MPa or more. Although the upper limit of Young's modulus is not particularly limited, it is about 30000 MPa.
  • the thickness of the base material is preferably 15 ⁇ m or more and 110 ⁇ m or less, more preferably 20 ⁇ m or more and 105 ⁇ m or less.
  • the material of the substrate may be selected so that the Young's modulus of the substrate is within the above range.
  • polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, polyester such as wholly aromatic polyester, polyimide, polyamide, polycarbonate, polyacetal, modified polyphenylene oxide, polyphenylene sulfide, polysulfone, polyether ketone, biaxially oriented A polypropylene etc. are mentioned.
  • one or more selected from polyester, polyamide, polyimide, and biaxially oriented polypropylene is preferable, polyester is more preferable, and polyethylene terephthalate is further preferable.
  • the substrate may also contain plasticizers, lubricants, infrared absorbers, ultraviolet absorbers, fillers, colorants, antistatic agents, antioxidants, catalysts, etc., as long as the effects of the present invention are not impaired.
  • the substrate may be transparent or opaque, and may be colored or vapor-deposited as desired.
  • At least one main surface of the base material may be subjected to adhesion treatment such as corona treatment in order to improve adhesion with other layers.
  • the base material may have a primer layer on at least one of its main surfaces.
  • the primer layer-forming composition for forming the primer layer is not particularly limited, but examples thereof include compositions containing polyester-based resins, urethane-based resins, polyester-urethane-based resins, acrylic-based resins, and the like.
  • the primer layer-forming composition may optionally contain a cross-linking agent, a photopolymerization initiator, an antioxidant, a softening agent (plasticizer), a filler, an antirust agent, a pigment, a dye, and the like. .
  • the thickness of the primer layer is preferably 0.01-10 ⁇ m, more preferably 0.03-5 ⁇ m. Since the material of the primer layer is soft, it has little effect on the Young's modulus, and the Young's modulus of the substrate is substantially the same as that of the resin film even when the primer layer is provided.
  • the Young's modulus of the base material can be controlled by selecting the resin composition, adding a plasticizer, and stretching conditions during resin film production.
  • the adhesive layer is attached to the circuit surface of the semiconductor wafer, protects the circuit surface, and supports the semiconductor wafer until it is peeled off from the circuit surface.
  • the pressure-sensitive adhesive layer is energy ray-curable.
  • the pressure-sensitive adhesive layer may be composed of one layer (single layer), or may be composed of multiple layers of two or more layers. When the pressure-sensitive adhesive layer has multiple layers, these multiple layers may be the same or different, and the combination of layers constituting these multiple layers is not particularly limited.
  • the thickness of the adhesive layer is not particularly limited, it is preferably 3 ⁇ m or more and 200 ⁇ m or less, more preferably 5 ⁇ m or more and 100 ⁇ m or less. When the thickness of the adhesive layer is within the above range, cracking of the wafer and movement of the chips can be suppressed.
  • the thickness of the adhesive layer means the thickness of the entire adhesive layer.
  • the thickness of a pressure-sensitive adhesive layer composed of multiple layers means the total thickness of all layers constituting the pressure-sensitive adhesive layer.
  • the adhesive layer has the following physical properties.
  • the surface resistivity of the adhesive layer after energy ray curing is 5.1 ⁇ 10 12 ⁇ /cm 2 or more and 1.0 ⁇ 10 15 ⁇ /cm 2 or less.
  • This surface resistivity is the surface resistivity of the surface of the adhesive layer that is attached to the adherend (the surface 30a of the adhesive layer in FIG. 1A).
  • the surface resistivity is within the above range, static electricity easily escapes from the protective sheet for semiconductor processing, and the wafer or chip group is suppressed from being charged during processing of the wafer to which the protective sheet for semiconductor processing is attached. be able to. Therefore, the steps of attaching a protective sheet for semiconductor processing to the front surface of the wafer, grinding the back surface of the wafer, peeling off the protective sheet for semiconductor processing, and transferring the wafer or chip group after peeling off the protective sheet for semiconductor processing. , etc., it is possible to suppress adhesion of foreign matter or the like to the wafer or the like. As a result, breakage and cracking of the wafer or the like due to adhesion of foreign matter or the like is suppressed.
  • the surface resistivity is within the above range, even if the protective sheet for semiconductor processing is peeled off, the movement of the separated chips is suppressed and the contact between the chips is reduced. Cracks can be suppressed.
  • the surface resistivity can be controlled to some extent by the amount of energy ray-polymerizable carbon-carbon double bonds in the pressure-sensitive adhesive layer before curing, and as the pressure-sensitive adhesive layer is cured, the surface resistivity increases. There is a tendency. Therefore, when the surface resistivity is smaller than the above range, the curing of the pressure-sensitive adhesive layer is insufficient. As a result, when the protective sheet for semiconductor processing is peeled off from the wafer or chip, a part of the adhesive layer remains attached to the wafer or chip (adhesive residue), or the chip cracks. Sometimes.
  • the surface resistivity is preferably 9.5 ⁇ 10 14 ⁇ /cm 2 or less, more preferably 9.0 ⁇ 10 14 ⁇ /cm 2 or less.
  • the surface resistivity is preferably 5.2 ⁇ 10 12 ⁇ /cm 2 or higher, more preferably 5.5 ⁇ 10 12 ⁇ /cm 2 or higher.
  • surface resistivity is measured according to JIS K 7194. That is, the measurement is performed in the same manner as the measurement method specified in JIS K 7194, but the measurement conditions may be different. Specific measurement conditions will be described later in Examples.
  • the adhesive strength when the adhesive layer after energy ray curing is peeled off from the silicon wafer so that the angle between the adhesive layer and the silicon wafer is 90° (hereinafter referred to as the adhesive after energy ray curing).
  • the 90° peeling adhesive strength of the agent layer is preferably less than 0.15 N/25 mm.
  • the 90° peeling adhesive strength of the adhesive layer after energy ray curing is more preferably 0.14 N/25 mm or less, more preferably 0.13 N/25 mm or less.
  • the 90° peeling adhesive strength of the adhesive layer after energy beam curing is preferably 0.035 N/25 mm or more.
  • the 90° peeling adhesive strength of the pressure-sensitive adhesive layer after curing with energy rays is determined according to JIS Z 0237 after the pressure-sensitive adhesive layer is attached to a silicon wafer and the pressure-sensitive adhesive layer is cured with energy rays.
  • the peeling speed of 600 mm/min tends to be faster than the peeling speed during normal adhesion measurement. This condition assumes the peeling speed at the time of peeling off the adhesive layer from a wafer or the like ground by DBG or LDBG. As the peel speed increases, the adhesive strength generally tends to increase.
  • the ratio of the 90° peeling adhesive strength of the adhesive layer before and after energy ray curing is preferably 4% or less. That is, the adhesive strength when the adhesive layer before energy beam curing is peeled off from the silicon wafer so that the angle between the adhesive layer and the silicon wafer is 90° (hereinafter referred to as the adhesive layer before energy beam curing).
  • the ratio of the 90° peeling adhesive strength of the adhesive layer after energy beam curing (hereinafter also referred to as the adhesive strength ratio) to the 90° peeling adhesive strength is preferably 4% or less.
  • the adhesive layer sufficiently adheres to the surface of the wafer to protect the circuit during back-grinding, and the adhesive layer does not peel off from the wafer, etc. after back-grinding. It becomes easy and the crack of a chip
  • the adhesive strength ratio is more preferably 3% or less, and even more preferably 2% or less.
  • the lower limit of the adhesive force ratio is not particularly limited, it is usually about 0.3%.
  • the 90° peeling adhesive strength of the pressure-sensitive adhesive layer before curing with energy rays is the 90° peeling strength of the pressure-sensitive adhesive layer after curing with energy rays, except for measuring the adhesive strength of the pressure-sensitive adhesive layer before curing with energy rays. It should be the same as the measurement method. Specific measurement conditions will be described later in Examples.
  • the composition of the pressure-sensitive adhesive layer is not particularly limited as long as the pressure-sensitive adhesive layer has adhesiveness to the extent that it can protect the circuit surface of the wafer and has the surface resistivity described above.
  • the pressure-sensitive adhesive layer contains, for example, an acrylic pressure-sensitive adhesive, a urethane-based pressure-sensitive adhesive, a rubber-based pressure-sensitive adhesive, a silicone-based pressure-sensitive adhesive, etc., as a pressure-sensitive adhesive component (adhesive resin) capable of expressing pressure-sensitive adhesiveness. It is preferably composed of a composition (composition for pressure-sensitive adhesive layer).
  • composition for the adhesive layer contains an energy ray-curable adhesive from the viewpoint of easily achieving the adhesive strength and adhesive strength ratio after energy ray curing.
  • composition for adhesive layer As described above, since the pressure-sensitive adhesive layer is energy ray-curable, it is formed from an energy ray-curable composition (composition for pressure-sensitive adhesive layer). Below, the composition for adhesive layers is demonstrated.
  • the composition for the pressure-sensitive adhesive layer may have energy ray-curable properties by blending an energy ray-curable compound separately from the adhesive resin, but the adhesive resin itself has energy ray-curable properties. is preferred.
  • an energy ray polymerizable group is introduced into the adhesive resin, and the energy ray polymerizable group is preferably introduced into the main chain or side chain of the adhesive resin. .
  • an energy ray-curable compound when blended separately from the adhesive resin, a monomer or oligomer having an energy ray-polymerizable group is used as the energy ray-curable compound.
  • the oligomer has a weight-average molecular weight (Mw) of less than 10,000, such as urethane (meth)acrylate.
  • the amount of energy ray-polymerizable carbon-carbon double bonds it is preferably 0.1 to 300 parts by mass with respect to 100 parts by mass of the adhesive resin that does not have energy ray-curable properties. , more preferably 0.5 to 200 parts by mass, more preferably 1 to 150 parts by mass.
  • the energy ray-curable adhesive resin contained in the adhesive layer composition is an energy ray-curable acrylic polymer (hereinafter also referred to as "acrylic polymer (A)"). A more detailed description will be given.
  • the acrylic polymer (A) is an acrylic polymer into which an energy ray-polymerizable group is introduced and which has structural units derived from (meth)acrylate.
  • the energy ray-polymerizable group is preferably introduced into the side chain of the acrylic polymer.
  • the acrylic polymer (A) is an acrylic copolymer (A0) having structural units derived from the alkyl (meth)acrylate (a1) and structural units derived from the functional group-containing monomer (a2), and is subjected to energy beam polymerization. It is preferably a reactant obtained by reacting a polymerizable compound (Xa) having a functional group.
  • alkyl (meth)acrylate (a1) an alkyl (meth)acrylate having an alkyl group with 1 to 18 carbon atoms is used. Specifically, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, n-pentyl (meth) acrylate, n-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, n-decyl (meth) acrylate, n-dodecyl (meth) acrylate, n-tridecyl (meth) acrylate, myristyl (meth) acrylate, palmityl (meth) acrylate, stearyl (meth) acrylate ) acrylates and the like.
  • the alkyl (meth)acrylate (a1) is preferably an alkyl (meth)acrylate having an alkyl group with 4 to 8 carbon atoms.
  • 2-ethylhexyl (meth)acrylate and n-butyl (meth)acrylate are preferred, and n-butyl (meth)acrylate is more preferred.
  • they may be used individually by 1 type, and may be used in combination of 2 or more type.
  • the content of the structural unit derived from the alkyl (meth)acrylate (a1) in the acrylic copolymer (A0) is adjusted to the acrylic copolymer (A0) from the viewpoint of improving the adhesive strength of the pressure-sensitive adhesive layer to be formed. is preferably 40 to 98% by mass, more preferably 45 to 95% by mass, and still more preferably 50 to 90% by mass, relative to the total structural units (100% by mass) of.
  • the alkyl (meth)acrylate (a1) may contain ethyl (meth)acrylate, methyl (meth)acrylate, etc. in addition to the above 2-ethylhexyl (meth)acrylate and n-butyl (meth)acrylate. good. By containing these monomers, it becomes easier to adjust the adhesive performance of the adhesive layer to a desired one.
  • the functional group-containing monomer (a2) is a monomer having a functional group such as a hydroxy group, a carboxyl group, an epoxy group, an amino group, a cyano group, a nitrogen atom-containing ring group, an alkoxysilyl group, or the like.
  • a functional group such as a hydroxy group, a carboxyl group, an epoxy group, an amino group, a cyano group, a nitrogen atom-containing ring group, an alkoxysilyl group, or the like.
  • the functional group-containing monomer (a2) among those mentioned above, one or more selected from hydroxyl group-containing monomers, carboxy group-containing monomers, and epoxy group-containing monomers are preferable.
  • hydroxy group-containing monomers examples include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 3-hydroxybutyl ( hydroxyalkyl (meth)acrylates such as meth)acrylate and 4-hydroxybutyl (meth)acrylate; and unsaturated alcohols such as vinyl alcohol and allyl alcohol.
  • Carboxy group-containing monomers include (meth)acrylic acid, maleic acid, fumaric acid, and itaconic acid.
  • Epoxy-containing monomers include epoxy group-containing (meth)acrylic acid esters and non-acrylic epoxy group-containing monomers.
  • epoxy group-containing (meth)acrylic esters include glycidyl (meth)acrylate, ⁇ -methylglycidyl (meth)acrylate, (3,4-epoxycyclohexyl)methyl (meth)acrylate, 3-epoxycyclo-2- Hydroxypropyl (meth)acrylate and the like.
  • non-acrylic epoxy group-containing monomers include glycidyl crotonate and allyl glycidyl ether.
  • the functional group-containing monomer (a2) may be used alone or in combination of two or more.
  • hydroxy group-containing monomers are more preferable, hydroxyalkyl (meth)acrylates are more preferable, and 2-hydroxyethyl (meth)acrylate is even more preferable.
  • the content of structural units derived from the functional group-containing monomer (a2) in the acrylic copolymer (A0) is preferably 1 based on the total structural units (100% by mass) of the acrylic copolymer (A0). ⁇ 35% by mass, more preferably 3 to 32% by mass, still more preferably 6 to 30% by mass.
  • the content is 1% by mass or more, a certain amount of functional groups that serve as reaction points with the polymerizable compound (Xa) can be secured. Therefore, the pressure-sensitive adhesive layer can be appropriately cured by irradiation with energy rays, so that the adhesive strength after irradiation with energy rays can be reduced. Moreover, if the content is 30% by mass or less, sufficient pot life can be ensured when the solution of the adhesive layer composition is applied to form the adhesive layer.
  • the acrylic copolymer (A0) may be a copolymer of an alkyl (meth)acrylate (a1) and a functional group-containing monomer (a2). It may be a copolymer with a monomer (a3) other than the components (a1) and (a2).
  • Other monomers (a3) include, for example, cyclohexyl (meth)acrylate, benzyl (meth)acrylate, isobornyl (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyloxy Examples include (meth)acrylates having a cyclic structure such as ethyl (meth)acrylate, vinyl acetate, styrene, and the like. Other monomers (a3) may be used singly or in combination of two or more.
  • the content of structural units derived from the other monomer (a3) in the acrylic copolymer (A0) is preferably 0 to 30% by mass, more preferably 0 to 10% by mass, and even more preferably 0 to 5% by mass.
  • the polymerizable compound (Xa) includes an energy ray-polymerizable group and a substituent capable of reacting with a functional group in the structural unit derived from the (a2) component of the acrylic copolymer (A0) (hereinafter simply referred to as "reactive substitution (also referred to as "group").
  • the energy ray-polymerizable group may be any group containing an energy ray-polymerizable carbon-carbon double bond.
  • a (meth)acryloyl group, a vinyl group and the like can be mentioned, and a (meth)acryloyl group is preferred.
  • the polymerizable compound (Xa) is preferably a compound having 1 to 5 energy ray-polymerizable groups per molecule.
  • the reactive substituent in the polymerizable compound (Xa) may be appropriately changed according to the functional group of the functional group-containing monomer (a2). From the viewpoint of reactivity and the like, an isocyanate group is preferred.
  • an isocyanate group is preferred.
  • the polymerizable compound (Xa) has an isocyanate group, for example, when the functional group of the functional group-containing monomer (a2) is a hydroxy group, it can easily react with the acrylic copolymer (A0). become.
  • Specific polymerizable compounds (Xa) include, for example, (meth)acryloyloxyethyl isocyanate, meta-isopropenyl- ⁇ , ⁇ -dimethylbenzyl isocyanate, (meth)acryloyl isocyanate, allyl isocyanate, glycidyl (meth)acrylate, (Meth) acrylic acid and the like. These polymerizable compounds (Xa) may be used alone or in combination of two or more.
  • the polymerizable compound (Xa) is added to the total amount of functional groups derived from the functional group-containing monomer (a2) in the acrylic copolymer (A0) (100 equivalents ), preferably 50 to 98 equivalents, more preferably 55 to 93 equivalents are reacted with the functional group.
  • the weight average molecular weight (Mw) of the acrylic polymer (A) is preferably 300,000 to 1,600,000, more preferably 400,000 to 1,400,000. By having such Mw, it becomes possible to impart appropriate adhesiveness to the adhesive layer.
  • the composition for the adhesive layer preferably contains an energy ray-curable compound other than the adhesive resin.
  • an energy ray-curable compound a monomer or oligomer having an unsaturated group in the molecule and capable of being polymerized and cured by energy ray irradiation is preferable.
  • trimethylolpropane tri(meth)acrylate pentaerythritol (meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, 1,4-butylene glycol di(meth)
  • Polyvalent (meth)acrylate monomers such as acrylates and 1,6-hexanediol (meth)acrylates
  • oligomers such as urethane (meth)acrylates, polyester (meth)acrylates, polyether (meth)acrylates, and epoxy (meth)acrylates is mentioned.
  • urethane (meth)acrylate oligomers are preferable from the viewpoint of having a relatively high molecular weight and keeping the surface resistivity of the pressure-sensitive adhesive layer within the range described above.
  • the content of the energy ray-curable compound is preferably 0.1 to 300 mass parts with respect to 100 mass parts of the acrylic polymer (A). parts, more preferably 0.5 to 200 parts by mass, and still more preferably 1 to 150 parts by mass.
  • the adhesive layer composition preferably further contains a cross-linking agent.
  • the pressure-sensitive adhesive layer composition is crosslinked by a crosslinking agent, for example, by being heated after application.
  • a crosslinking agent for example, by being heated after application.
  • cross-linking agents examples include isocyanate-based cross-linking agents, epoxy-based cross-linking agents, aziridine-based cross-linking agents, and chelate-based cross-linking agents. Among these, isocyanate-based cross-linking agents are preferred. You may use a crosslinking agent individually or in combination of 2 or more types.
  • isocyanate-based cross-linking agents include polyisocyanate compounds.
  • polyisocyanate compounds include aromatic polyisocyanates such as tolylene diisocyanate, diphenylmethane diisocyanate and xylylene diisocyanate; aliphatic polyisocyanates such as hexamethylene diisocyanate; and alicyclic polyisocyanates such as isophorone diisocyanate and hydrogenated diphenylmethane diisocyanate. etc.
  • biuret and isocyanurate forms thereof as well as adduct forms which are reactants with low-molecular-weight active hydrogen-containing compounds such as ethylene glycol, propylene glycol, neopentyl glycol, trimethylolpropane and castor oil.
  • polyhydric alcohol for example, trimethylolpropane, etc.
  • aromatic polyisocyanates such as tolylene diisocyanate are preferable.
  • the content of the cross-linking agent is preferably 0.01 to 10 parts by mass, more preferably 0.03 to 7 parts by mass, based on 100 parts by mass of the acrylic polymer (A).
  • the adhesive layer composition preferably further contains a photopolymerization initiator.
  • a photopolymerization initiator it becomes easier to proceed the energy ray curing of the composition for the pressure-sensitive adhesive layer by ultraviolet light or the like.
  • photopolymerization initiators include acetophenone, 2,2-diethoxybenzophenone, 4-methylbenzophenone, 2,4,6-trimethylbenzophenone, Michler's ketone, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzyldiphenisulfide, tetramethylthiuram monosulfide, benzyldimethylketal, dibenzyl, diacetyl, 1-chloroanthraquinone, 2-chloroanthraquinone, 2-ethylanthraquinone, 2,2-dimethoxy-1,2-diphenylethane- 1-one, 1-hydroxycyclohexylphenyl ketone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropanone-1,2-benzyl-2-dimethylamino-1-(4-
  • the photopolymerization initiator may be used alone or in combination of two or more. Among the above, 2,2-dimethoxy-1,2-diphenylethan-1-one and 1-hydroxycyclohexylphenyl ketone are preferred.
  • the content of the photopolymerization initiator is preferably 0.01 to 10 parts by mass, more preferably 0.03 to 7 parts by mass, and still more preferably 0.05 parts by mass with respect to 100 parts by mass of the acrylic polymer (A). ⁇ 5 parts by mass.
  • the composition for the pressure-sensitive adhesive layer may contain other additives as long as they do not impair the effects of the present invention.
  • Other additives include, for example, tackifiers, antioxidants, softeners (plasticizers), fillers, rust inhibitors, pigments, dyes, and the like.
  • the content of each additive is preferably 0.01 to 6 parts by mass, more preferably 0.02 to 2 parts by mass, relative to 100 parts by mass of the acrylic polymer (A). part by mass.
  • the surface resistivity and adhesive strength of the pressure-sensitive adhesive layer are determined, for example, by the type and amount of monomers constituting the acrylic polymer (A), and the amount of energy ray-polymerizable groups introduced into the acrylic polymer (A). etc. can be adjusted.
  • the above describes the preferred range of the amount of the energy ray-polymerizable group to be introduced into the acrylic polymer (A).
  • the surface resistivity tends to be high.
  • the surface resistivity and adhesive strength of the adhesive layer can be adjusted by factors other than those mentioned above. For example, it can be appropriately adjusted by adjusting the amount of the cross-linking agent and the amount of the photopolymerization initiator mixed in the pressure-sensitive adhesive layer.
  • the antistatic layer is arranged between the substrate and the adhesive layer.
  • the antistatic component can suppress an increase in static voltage due to leakage of static charge resulting from processing of the wafer to which the protective sheet for semiconductor processing is adhered.
  • the composition of the antistatic layer may have such an antistatic property that the peeling electrostatic voltage when peeling the pressure-sensitive adhesive layer from a wafer or the like can be reduced to a predetermined value or less. In this embodiment, it is preferable that the peeling electrification voltage is 500 V or less.
  • the thickness of the antistatic layer is preferably 10 nm or more, more preferably 15 nm or more, even more preferably 20 nm or more, and particularly preferably 60 nm or more. Also, the thickness is preferably 300 nm or less, more preferably 250 nm or less, and even more preferably 200 nm or less.
  • the antistatic layer is preferably composed of a composition containing a polymer compound (composition for antistatic layer).
  • composition for antistatic layer examples include a composition containing a conductive polymer compound as an antistatic component, a composition containing an antistatic component and a polymer compound, and the like.
  • the antistatic layer composition is preferably a composition containing a conductive polymer compound.
  • Examples of conductive polymer compounds include polythiophene-based polymers, polypyrrole-based polymers, and polyaniline-based polymers. In this embodiment, a polythiophene-based polymer is preferred.
  • Polythiophene-based polymers include, for example, polythiophene, poly(3-alkylthiophene), poly(3-thiophene- ⁇ -ethanesulfonic acid), mixtures of polyalkylenedioxythiophenes and polystyrene sulfonate (PSS) (doped including) and the like. Among these, a mixture of polyalkylenedioxythiophene and polystyrene sulfonate is preferred. Examples of the polyalkylenedioxythiophene include poly(3,4-ethylenedioxythiophene) (PEDOT), polypropylenedioxythiophene, poly(ethylene/propylene)dioxythiophene, etc.
  • PEDOT poly(3,4-ethylenedioxythiophene)
  • PEDOT polypropylenedioxythiophene
  • poly(ethylene/propylene)dioxythiophene etc.
  • poly(3,4- ethylenedioxythiophene) is preferred. That is, among the above, a mixture of poly(3,4-ethylenedioxythiophene) and polystyrene sulfonate (PSS-doped PEDOT) is particularly preferred.
  • polypyrrole-based polymers examples include polypyrrole, poly-3-methylpyrrole, and poly-3-octylpyrrole.
  • polyaniline-based polymers examples include polyaniline, polymethylaniline, and polymethoxyaniline.
  • a composition containing an antistatic component and a polymer compound includes a composition containing an antistatic component and a binder resin.
  • the antistatic component include the above conductive polymer compounds, surfactants, ionic liquids, conductive inorganic compounds, and the like.
  • the surfactant may be at least one selected from cationic surfactants, anionic surfactants, amphoteric surfactants, and nonionic surfactants. Examples include cationic surfactants containing quaternary ammonium salts. Examples of conductive inorganic compounds include various metals and conductive oxides.
  • the binder resin is not particularly limited. Examples thereof include polyester resins, acrylic resins, polyvinyl resins, urethane resins, melamine resins, and epoxy resins. Moreover, you may use a crosslinking agent together. Examples of cross-linking agents include methylolated or alkylolated melamine compounds, urea compounds, glyoxal compounds, acrylamide compounds, epoxy compounds, isocyanate compounds, and the like.
  • the content of the antistatic agent in the antistatic layer composition may be appropriately determined according to the desired antistatic performance. Specifically, the content of the antistatic agent in the antistatic layer composition is preferably 0.1 to 20% by mass.
  • the buffer layer as shown in FIG. 1A, is formed on the main surface of the base material opposite to the main surface on which the pressure-sensitive adhesive layer is formed.
  • the buffer layer 40 is a softer layer than the base material, and relieves the stress during back-grinding of the wafer to prevent cracking and chipping of the wafer.
  • the wafer to which the protective sheet for semiconductor processing is attached is placed on the vacuum table through the protective sheet for semiconductor processing during back grinding. It is easier to hold properly on the vacuum table.
  • Such a buffer layer is useful when processing wafers by DBG, especially LDBG.
  • the thickness of the buffer layer is preferably 5-100 ⁇ m, more preferably 1-100 ⁇ m, and even more preferably 5-80 ⁇ m. By setting the thickness of the buffer layer within the above range, the buffer layer can appropriately relax the stress during back grinding.
  • the buffer layer may be a layer formed from a buffer layer composition containing an energy ray-polymerizable compound, a polypropylene film, an ethylene-vinyl acetate copolymer film, an ionomer resin film, an ethylene/(meth)acrylic film. Films such as acid copolymer films, ethylene/(meth)acrylate copolymer films, LDPE films, and LLDPE films may be used.
  • a buffer layer composition containing an energy ray-polymerizable compound can be cured by being irradiated with an energy ray.
  • the buffer layer composition containing the energy ray-polymerizable compound is more specifically polymerizable having a urethane (meth)acrylate (b1) and an alicyclic or heterocyclic group having 6 to 20 ring-forming atoms. It preferably contains the compound (b2).
  • the buffer layer composition may contain a polymerizable compound (b3) having a functional group.
  • the buffer layer composition may also contain a photopolymerization initiator in addition to the above components.
  • the buffer layer composition may contain other additives and resin components within the range that does not impair the effects of the present invention.
  • Urethane (meth)acrylate (b1) is a compound having at least a (meth)acryloyl group and a urethane bond, and has the property of being polymerized and cured by energy ray irradiation.
  • Urethane (meth)acrylates (b1) are oligomers or polymers.
  • the weight average molecular weight (Mw) of component (b1) is preferably 1,000 to 100,000, more preferably 2,000 to 60,000, still more preferably 3,000 to 20,000.
  • the number of (meth)acryloyl groups (hereinafter also referred to as "number of functional groups") in component (b1) may be monofunctional, difunctional, or trifunctional or more, but is preferably monofunctional or difunctional. .
  • Component (b1) can be obtained, for example, by reacting a terminal isocyanate urethane prepolymer obtained by reacting a polyol compound and a polyvalent isocyanate compound with a (meth)acrylate having a hydroxyl group.
  • a component (b1) individually or in combination of 2 or more types.
  • the polyol compound used as the raw material for component (b1) is not particularly limited as long as it is a compound having two or more hydroxy groups. Any of difunctional diols, trifunctional triols, and tetrafunctional or higher polyols may be used, but bifunctional diols are preferred, and polyester type diols or polycarbonate type diols are more preferred.
  • polyvalent isocyanate compounds include aliphatic polyisocyanates such as tetramethylene diisocyanate, hexamethylene diisocyanate and trimethylhexamethylene diisocyanate; Alicyclic diisocyanates such as ,4'-diisocyanate, ⁇ , ⁇ '-diisocyanatedimethylcyclohexane; 4,4'-diphenylmethane diisocyanate, tolylene diisocyanate, xylylene diisocyanate, tolidine diisocyanate, tetramethylene xylylene diisocyanate, naphthalene- aromatic diisocyanates such as 1,5-diisocyanate;
  • isophorone diisocyanate hexamethylene diisocyanate, and xylylene diisocyanate are preferred.
  • a urethane (meth)acrylate (b1) can be obtained by reacting a (meth)acrylate having a hydroxyl group with a terminal isocyanate urethane prepolymer obtained by reacting the above-mentioned polyol compound and a polyvalent isocyanate compound.
  • the (meth)acrylate having a hydroxy group is not particularly limited as long as it is a compound having a hydroxy group and a (meth)acryloyl group in at least one molecule.
  • Specific (meth)acrylates having a hydroxy group include, for example, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 4-hydroxycyclohexyl (meth) Acrylate, 5-hydroxycyclooctyl (meth)acrylate, 2-hydroxy-3-phenyloxypropyl (meth)acrylate, pentaerythritol tri(meth)acrylate, polyethylene glycol mono(meth)acrylate, polypropylene glycol mono(meth)acrylate, etc.
  • hydroxyalkyl (meth)acrylate hydroxy group-containing (meth)acrylamide such as N-methylol (meth)acrylamide
  • hydroxyalkyl (meth)acrylates are preferred, and 2-hydroxyethyl (meth)acrylate is more preferred.
  • the content of component (b1) in the buffer layer composition is preferably 10 to 70% by mass, more preferably 20 to 60% by mass, based on the total amount (100% by mass) of the buffer layer composition. It is preferably 25 to 55% by mass.
  • Component (b2) is a polymerizable compound having an alicyclic or heterocyclic group having 6 to 20 ring atoms, and more preferably a compound having at least one (meth)acryloyl group. Compounds having one (meth)acryloyl group are preferred. By using the component (b2), it is possible to improve the film formability of the obtained buffer layer composition.
  • Specific components (b2) include, for example, isobornyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentenyloxy (meth)acrylate, cyclohexyl (meth)acrylate, alicyclic group-containing (meth)acrylates such as adamantane (meth)acrylate; heterocyclic group-containing (meth)acrylates such as tetrahydrofurfuryl (meth)acrylate and morpholine (meth)acrylate; and the like.
  • alicyclic group-containing (meth)acrylates isobornyl (meth)acrylate is preferred, and among heterocyclic group-containing (meth)acrylates, tetrahydrofurfuryl (meth)acrylate is preferred.
  • the content of the component (b2) in the buffer layer composition is preferably 10 to 70% by mass, more preferably 20 to 60% by mass, based on the total amount (100% by mass) of the buffer layer composition. It is preferably 25 to 55% by mass.
  • Component (b3) is a polymerizable compound containing a functional group such as a hydroxyl group, an epoxy group, an amide group, or an amino group, and is preferably a compound having at least one (meth)acryloyl group. Compounds having one (meth)acryloyl group are preferred.
  • the component (b3) has good compatibility with the component (b1), and it becomes easy to adjust the viscosity of the buffer layer composition to an appropriate range. Moreover, even if the buffer layer is made relatively thin, the buffer performance is improved.
  • component (b3) examples include hydroxyl group-containing (meth)acrylates, epoxy group-containing compounds, amide group-containing compounds, amino group-containing (meth)acrylates, and the like. Among these, hydroxyl group-containing (meth)acrylates are preferred.
  • hydroxyl group-containing (meth)acrylates examples include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxy Butyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, phenylhydroxypropyl (meth)acrylate, 2-hydroxy-3-phenoxypropyl acrylate and the like.
  • hydroxyl group-containing (meth)acrylates having an aromatic ring such as phenylhydroxypropyl (meth)acrylate are more preferable.
  • the component (b3) may be used alone or in combination of two or more.
  • the content of the component (b3) in the buffer layer composition is preferably 5% with respect to the total amount (100% by mass) of the buffer layer composition in order to improve the film-forming properties of the buffer layer composition. ⁇ 40% by mass, more preferably 7 to 35% by mass, still more preferably 10 to 30% by mass.
  • the buffer layer-forming composition may contain a polymerizable compound (b4) other than the components (b1) to (b3) as long as the effects of the present invention are not impaired.
  • component (b4) examples include alkyl (meth)acrylates having an alkyl group having 1 to 20 carbon atoms; styrene, hydroxyethyl vinyl ether, hydroxybutyl vinyl ether, N-vinylformamide, N-vinylpyrrolidone, N-vinylcaprolactam, and the like. vinyl compound of: and the like. In addition, you may use a component (b4) individually or in combination of 2 or more types.
  • the content of component (b4) in the buffer layer-forming composition is preferably 0 to 20% by mass, more preferably 0 to 10% by mass, even more preferably 0 to 5% by mass, and particularly preferably 0 to 2% by mass. %.
  • the buffer layer composition preferably further contains a photopolymerization initiator from the viewpoint of shortening the polymerization time by energy ray irradiation and reducing the amount of energy ray irradiation when forming the buffer layer.
  • photopolymerization initiators examples include benzoin compounds, acetophenone compounds, acylphosphine oxide compounds, titanocene compounds, thioxanthone compounds, peroxide compounds, and photosensitizers such as amines and quinones.
  • 1-hydroxycyclohexylphenyl ketone 2-hydroxy-2-methyl-1-phenyl-propan-1-one
  • benzoin benzoin methyl ether
  • benzoin ethyl ether benzoin isopropyl ether
  • benzylphenyl sulfide tetramethylthiuram monosulfide
  • azobisisobutyrolnitrile dibenzyl, diacetyl, 8-chloroanthraquinone, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide and the like.
  • photopolymerization initiators can be used alone or in combination of two or more.
  • the content of the photopolymerization initiator in the buffer layer composition is preferably 0.05 to 15 parts by mass, more preferably 0.1 to 10 parts by mass, with respect to 100 parts by mass of the total amount of the energy ray-polymerizable compound. parts, more preferably 0.3 to 5 parts by mass.
  • the buffer layer composition may contain other additives as long as the effects of the present invention are not impaired.
  • Other additives include, for example, antistatic agents, antioxidants, softeners (plasticizers), fillers, rust inhibitors, pigments, dyes, and the like.
  • the content of each additive in the buffer layer composition is preferably 0.01 to 6 parts by mass, more than It is preferably 0.1 to 3 parts by mass.
  • the buffer layer formed from the buffer layer composition containing the energy ray-polymerizable compound is obtained by polymerizing and curing the buffer layer composition having the above composition by energy ray irradiation. That is, the buffer layer is a hardened material of the buffer layer composition.
  • the buffer layer preferably contains polymerized units derived from component (b1) and polymerized units derived from component (b2). Moreover, the buffer layer may contain a polymerized unit derived from the component (b3) or may contain a polymerized unit derived from the component (b4).
  • the content ratio of each polymer unit in the buffer layer usually corresponds to the ratio (feed ratio) of each component constituting the composition for the buffer layer.
  • a release sheet may be attached to the surface of the protective sheet for semiconductor processing. Specifically, the release sheet is attached to the surface of the pressure-sensitive adhesive layer of the protective sheet for semiconductor processing. The release sheet is attached to the surface of the adhesive layer to protect the adhesive layer during transportation and storage. The release sheet is releasably attached to the semiconductor processing protective sheet, and is peeled off and removed from the semiconductor processing protective sheet before the semiconductor processing protective sheet is used (that is, before the wafer is attached).
  • a release sheet having at least one surface subjected to a release treatment is used, and specific examples include a release sheet base material coated with a release agent on the surface.
  • a resin film is preferable, and as the resin constituting the resin film, for example, polyester resin films such as polyethylene terephthalate resin, polybutylene terephthalate resin, polyethylene naphthalate resin, polypropylene resin, polyethylene resin, etc. and the like polyolefin resins.
  • polyester resin films such as polyethylene terephthalate resin, polybutylene terephthalate resin, polyethylene naphthalate resin, polypropylene resin, polyethylene resin, etc. and the like polyolefin resins.
  • release agents include rubber-based elastomers such as silicone-based resins, olefin-based resins, isoprene-based resins and butadiene-based resins, long-chain alkyl-based resins, alkyd-based resins, fluorine-based resins, and the like.
  • the thickness of the release sheet is not particularly limited, it is preferably 10 to 200 ⁇ m, more preferably 20 to 150 ⁇ m.
  • the method for producing the protective sheet for semiconductor processing according to the present embodiment is not particularly limited as long as it is a method capable of forming an antistatic layer, a buffer layer and an adhesive layer on the main surface of the substrate, and a known method can be used. Just do it. A method of manufacturing the protective sheet for semiconductor processing shown in FIG. 1A will be described below.
  • an antistatic layer composition containing the above-described components or a composition obtained by diluting the antistatic layer composition with a solvent or the like is prepared.
  • the adhesive layer composition for forming the adhesive layer may be, for example, a pressure-sensitive adhesive layer composition containing the above-described components, or a composition obtained by diluting the pressure-sensitive adhesive layer composition with a solvent or the like.
  • the buffer layer composition for forming the buffer layer for example, a buffer layer composition containing the above-described components, or a composition obtained by diluting the buffer layer composition with a solvent or the like is prepared. .
  • solvents examples include organic solvents such as methyl ethyl ketone, acetone, ethyl acetate, tetrahydrofuran, dioxane, cyclohexane, n-hexane, toluene, xylene, n-propanol and isopropanol.
  • the buffer layer composition is applied to the release-treated surface of the first release sheet by a spin coating method, a spray coating method, a bar coating method, a knife coating method, a roll coating method, a blade coating method, a die coating method, a gravure coating method, or the like.
  • a coating film is formed by coating by a known method, and this coating film is semi-cured to form a buffer layer film on a release sheet.
  • the buffer layer film formed on the release sheet is adhered to one surface of the substrate, and the buffer layer film is completely cured to form a buffer layer on the substrate.
  • the coating film is preferably cured by irradiation with energy rays. Moreover, the curing of the coating film may be performed in one curing process, or may be performed in a plurality of times.
  • an antistatic layer composition is applied to the release-treated surface of the second release sheet by a known method and dried by heating to form an antistatic layer on the second release sheet. After that, the antistatic layer on the second release sheet and the surface of the substrate on which the buffer layer is not formed are attached together, and the second release sheet is removed.
  • the adhesive layer composition is applied to the release-treated surface of the third release sheet by a known method and dried by heating to form an adhesive layer on the third release sheet.
  • the adhesive layer on the third release sheet and the antistatic layer on the base material are laminated to form an antistatic layer and an adhesive layer in this order on one main surface of the base material.
  • a protective sheet for semiconductor processing having a buffer layer formed on the other main surface of the substrate is obtained.
  • the third release sheet may be removed when using the protective sheet for semiconductor processing.
  • the protective sheet for semiconductor processing according to the present invention is preferably used in DBG when the back surface of the wafer is ground by being attached to the front surface of the semiconductor wafer.
  • the protective sheet for semiconductor processing according to the present invention is preferably used for LDBG in which a chip group with a small kerf width can be obtained when a semiconductor wafer is singulated.
  • the method for manufacturing a semiconductor device will be described in more detail below.
  • the method for manufacturing a semiconductor device includes at least steps 1 to 4 below.
  • Step 1 Affixing the protective sheet for semiconductor processing to the surface of the semiconductor wafer
  • Step 2 Forming a groove from the front surface side of the semiconductor wafer, or reforming the inside of the semiconductor wafer from the front surface or the back surface of the semiconductor wafer
  • Step 3 The semiconductor wafer on which the protective sheet for semiconductor processing is attached to the surface and the grooves or modified regions are formed is ground from the back side, and the grooves or modified regions are used as starting points.
  • Step 4 A step of peeling off the protective sheet for semiconductor processing from the singulated semiconductor wafer (that is, chip group)
  • Step 1 In step 1, as shown in FIG. 2, the main surface 30a of the adhesive layer 30 of the protective sheet for semiconductor processing 1 according to the present embodiment is attached to the surface 100a of the semiconductor wafer 100 . By attaching the protective sheet for semiconductor processing to the surface of the semiconductor wafer, the surface of the semiconductor wafer is sufficiently protected.
  • step 1 may be performed before step 2, which will be described later, or after step 2.
  • step 1 is preferably performed before step 2.
  • step 1 is performed after step 2.
  • the semiconductor wafer used in this manufacturing method may be a silicon wafer, a wafer of gallium arsenide, silicon carbide, lithium tantalate, lithium niobate, gallium nitride, indium phosphide, or the like, or a glass wafer.
  • the semiconductor wafer is preferably a silicon wafer.
  • the thickness of the semiconductor wafer before grinding is not particularly limited, it is usually about 500 to 1000 ⁇ m.
  • a semiconductor wafer usually has a circuit formed on its surface. Formation of circuits on the wafer surface can be performed by various methods including conventional methods such as an etching method and a lift-off method.
  • Step 2 grooves are formed from the front surface side of the semiconductor wafer.
  • a modified region is formed inside the semiconductor wafer from the front surface or rear surface of the semiconductor wafer.
  • the grooves formed in this process are shallower than the thickness of the semiconductor wafer.
  • the grooves can be formed by dicing using a conventionally known wafer dicing device or the like. Also, the semiconductor wafer is divided into a plurality of semiconductor chips along the grooves in step 3, which will be described later.
  • the modified region is an embrittled portion of the semiconductor wafer, and the semiconductor wafer is thinned by grinding in the grinding process, and the modified region of the semiconductor wafer is destroyed by the application of grinding force. It is a starting point for separating into semiconductor chips. That is, in step 2, the grooves and modified regions are formed along dividing lines along which the semiconductor wafer is divided into individual semiconductor chips in step 3, which will be described later.
  • the modified region is formed by laser irradiation focused on the inside of the semiconductor wafer, and the modified region is formed inside the semiconductor wafer.
  • the laser irradiation may be performed from the front side or the back side of the semiconductor wafer.
  • the semiconductor wafer is irradiated with the laser through the protective sheet for semiconductor processing.
  • a semiconductor wafer on which a semiconductor processing protection sheet is attached and grooves or modified regions are formed is placed on a chuck table, and is held by being sucked by the chuck table. At this time, the semiconductor wafer is sucked with its surface side arranged on the table side.
  • Step 3 After steps 1 and 2, the back surface of the semiconductor wafer on the chuck table is ground to singulate the semiconductor wafer into a plurality of semiconductor chips to obtain a chip group.
  • the back surface grinding is performed so as to thin the semiconductor wafer at least to the position reaching the bottom of the groove.
  • the grooves become cuts penetrating the wafer, and the semiconductor wafer is divided by the cuts into individual semiconductor chips.
  • the ground surface may reach the modified region by grinding, but it does not have to reach the modified region strictly. That is, the semiconductor wafer may be ground from the modified region to a position close to the modified region so that the semiconductor wafer is broken into individual semiconductor chips starting from the modified region.
  • the actual singulation of the semiconductor chips may be performed by applying a pick-up tape, which will be described later, and then stretching the pick-up tape.
  • dry polishing may be performed prior to picking up the chips.
  • the shape of the individualized semiconductor chips may be a square or an elongated shape such as a rectangle.
  • the thickness of the individualized semiconductor chips is not particularly limited, it is preferably about 5 to 100 ⁇ m, more preferably 10 to 45 ⁇ m.
  • LDBG a modified region is provided inside the wafer with a laser, and the wafer is singulated by stress or the like during wafer backside grinding. ⁇ 45 ⁇ m becomes easy.
  • the size of the individualized semiconductor chips is not particularly limited, but the chip size is preferably less than 600 mm 2 , more preferably less than 400 mm 2 , still more preferably less than 120 mm 2 .
  • the protective sheet for semiconductor processing according to the present embodiment is used, even a thin and/or small semiconductor chip is charged during back grinding (step 3) and during peeling of the protective sheet for semiconductor processing (step 4). This prevents cracks from occurring in the semiconductor chip.
  • Step 4 the protective sheet for semiconductor processing is peeled off from the individualized semiconductor wafer (that is, a plurality of semiconductor chips). This step is performed, for example, by the following method.
  • the adhesive layer of the protective sheet for semiconductor processing is formed from an energy ray-curable adhesive
  • the adhesive layer is cured and shrunk by irradiating the energy ray, and the adherend (individualized) (semiconductor wafer).
  • a pick-up tape is attached to the rear surface side of the separated semiconductor wafer, and the position and direction are aligned so that pick-up is possible.
  • the ring frame arranged on the outer peripheral side of the wafer is also adhered to the pick-up tape, and the outer peripheral edge of the pick-up tape is fixed to the ring frame.
  • the wafer and the ring frame may be attached to the pickup tape at the same time, or may be attached at separate timings.
  • the protective sheet for semiconductor processing is peeled off from the plurality of semiconductor chips held on the pickup tape.
  • the protective sheet for semiconductor processing according to the present embodiment has the above-described properties, even when the protective sheet for semiconductor processing is peeled off from a semiconductor wafer at a high peeling speed, electrification is suppressed and the semiconductor wafer, etc.
  • the peeling can be performed in a state in which the contact between the chips is suppressed without leaving any adhesive residue.
  • the pickup tape is not particularly limited, it is composed of, for example, a base material and an adhesive sheet having an adhesive layer provided on one side of the base material.
  • the protective sheet for semiconductor processing according to the present invention is used in a method for singulating semiconductor wafers by DBG or LDBG. It can be preferably used for LDBG in which a thinned chip group with a small kerf width is obtained.
  • the measurement method and evaluation method in this example are as follows.
  • the protective sheets for semiconductor processing prepared in Examples and Comparative Examples were cut into a size of 10 cm ⁇ 10 cm, and the pressure-sensitive adhesive layer of the protective sheet for semiconductor processing was irradiated with ultraviolet rays to be cured.
  • the surface resistivity of the adhesive layer after curing was measured according to JIS K 7194 under the conditions of 23° C., 50% RH, and an applied voltage of 100 V using a surface resistivity meter R8252 manufactured by Advantest.
  • the protective sheets for semiconductor processing produced in Examples and Comparative Examples were cut to a width of 25 mm to obtain test pieces.
  • the pressure-sensitive adhesive layer of the test piece was applied to a silicon mirror wafer having no circuit surface formed thereon with a roller having a mass of 2 kg. After leaving it for 1 hour, the test piece was peeled off at a peeling speed of 600 mm / min so that it was 90° to the silicon mirror wafer in accordance with JIS Z 0237, and the adhesive strength (the pressure-sensitive adhesive layer before curing with the energy beam 90° peel adhesion) was measured.
  • the pressure-sensitive adhesive layer of another test piece was attached to the silicon mirror wafer with a roller having a mass of 2 kg.
  • the pressure-sensitive adhesive layer of this test piece was irradiated with ultraviolet rays from the substrate side of the protective sheet for semiconductor processing under the conditions of an illuminance of 220 mW/cm 2 and a light amount of 380 mJ/cm 2 to cure the pressure-sensitive adhesive layer.
  • the test piece was peeled off at a peeling speed of 600 mm / min so that it was 90 ° to the silicon mirror wafer, and the adhesive strength (90 ° peeling adhesive strength of the adhesive layer after energy ray curing ) was measured.
  • the protective sheet for semiconductor processing prepared in Examples and Comparative Examples was attached to the surface of a silicon wafer, and a wafer mounter (product name “RAD-2700F/12”, manufactured by Lintec) was used to peel off at a rate of 600 mm / min and at a temperature of While peeling the protective sheet for semiconductor processing from the silicon wafer at 40° C., the voltage is measured at a place 10 mm away from the wafer surface and the peeling surface side of the adhesive layer using a Prostat peeling electrification meter PFM-711A. Then, the voltage value on the wafer side was taken as the peeling electrification voltage value. In this example, samples with a peeling electrification voltage of 500 V or less were judged to be good.
  • a silicon wafer with a diameter of 12 inches and a thickness of 775 ⁇ m is attached to a protective sheet for semiconductor processing prepared in Examples and Comparative Examples using a tape laminator for back grinding (manufactured by Lintec, device name “RAD-3510F/12”). bottom.
  • a tape laminator for back grinding manufactured by Lintec, device name “RAD-3510F/12”. bottom.
  • a laser saw manufactured by Disco, device name "DFL7361”
  • a grid-shaped modified region was formed on the wafer. Note that the grid size was 10 mm ⁇ 10 mm.
  • the wafer was ground (including dry polishing) to a thickness of 30 ⁇ m, and the wafer was singulated into a plurality of chips.
  • Adhesive layer Preparation of composition for adhesive layer
  • An acrylic polymer obtained by copolymerizing 65 parts by mass of butyl acrylate (BA), 20 parts by mass of methyl methacrylate (MMA), and 15 parts by mass of 2-hydroxyethyl acrylate (2HEA) is added with all hydroxyl groups of the acrylic polymer.
  • 2-Methacryloyloxyethyl isocyanate (MOI) was reacted so as to be added to hydroxyl groups of 80 mol % of them to obtain an energy ray-curable acrylic resin (Mw: 500,000).
  • Release sheet manufactured by Lintec, trade name “SP-PET381031”, polyethylene terephthalate (PET) film subjected to silicone release treatment, thickness: 38 ⁇ m.
  • the solution was applied and dried to prepare a release sheet with an adhesive layer having an adhesive layer with a thickness of 20 ⁇ m.
  • PET50A- 4100 primer-attached PET film
  • a polythiophene-based conductive polymer (Denatron P-400MP, manufactured by Nagase Chemtech Co., Ltd.) is applied to the surface of the PET film opposite to the surface on which the first primer layer is provided, and dried to obtain a thickness. A 120 nm antistatic layer was formed on the PET film.
  • Buffer layer (synthesis of urethane acrylate oligomer (UA-1))
  • a terminal isocyanate urethane prepolymer obtained by reacting a polyester diol and isophorone diisocyanate is reacted with 2-hydroxyethyl acrylate to obtain a bifunctional urethane acrylate oligomer (UA-1) having a weight average molecular weight (Mw) of 5000. got
  • composition for forming buffer layer As energy ray-polymerizable compounds, 40 parts by mass of urethane acrylate oligomer (UA-1) synthesized in Production Example 1, 40 parts by mass of isobornyl acrylate (IBXA), and 20 parts by mass of phenylhydroxypropyl acrylate (HPPA) are blended. Then, 2.0 parts by mass of 1-hydroxycyclohexylphenyl ketone (manufactured by IGM Resins, product name “OMNIRAD184”) as a photopolymerization initiator and 0.2 parts by mass of a phthalocyanine pigment are blended to form a buffer layer. A composition was prepared.
  • the above ultraviolet irradiation is performed using a belt conveyor type ultraviolet irradiation device (product name "ECS-401GX", manufactured by Eyegraphics) and a high-pressure mercury lamp (H04-L41 manufactured by Eyegraphics: H04-L41).
  • ECS-401GX belt conveyor type ultraviolet irradiation device
  • H04-L41 high-pressure mercury lamp
  • the measurement was performed under irradiation conditions of a height of 150 mm, a lamp output of 3 kW (converted output of 120 mW/cm), an illuminance of 120 mW/cm 2 at a light wavelength of 365 nm, and a dose of 100 mJ/cm 2 .
  • the surface of the formed buffer layer-forming film and the first primer layer of the base material with an antistatic layer are laminated together, and ultraviolet rays are again irradiated from the release sheet side on the buffer layer-forming film to remove the buffer layer-forming film. It was completely cured to form a buffer layer with a thickness of 50 ⁇ m.
  • the above ultraviolet irradiation uses the above-described ultraviolet irradiation device and high-pressure mercury lamp, with a lamp height of 150 mm, a lamp output of 3 kW (converted output of 120 mW/cm), an illuminance of 160 mW/cm 2 at a light wavelength of 365 nm, and an irradiation amount of 500 mJ. / cm 2 irradiation conditions.
  • Example 2 A protective sheet for semiconductor processing was obtained in the same manner as in Example 1, except that the thickness of the antistatic layer was 150 nm and the thickness of the adhesive layer was 5 ⁇ m.
  • Example 3 A protective sheet for semiconductor processing was obtained in the same manner as in Example 1, except that the thickness of the antistatic layer was 80 nm and the thickness of the adhesive layer was 200 ⁇ m.
  • Example 4 A protective sheet for semiconductor processing was obtained in the same manner as in Example 1, except that the following adhesive layer composition was used to form the adhesive layer.
  • composition for adhesive layer An acrylic polymer (Mw: 800,000) was obtained by copolymerizing 89 parts by mass of n-butyl acrylate (BA), 8 parts by mass of methyl methacrylate (MMA), and 3 parts by mass of 2-hydroxyethyl acrylate (2HEA). .
  • Example 5 A protective sheet for semiconductor processing was prepared in the same manner as in Example 1, except that a pressure-sensitive adhesive layer was formed using the following pressure-sensitive adhesive layer composition, and the thickness of the antistatic layer was 25 nm and the thickness of the pressure-sensitive adhesive layer was 5 ⁇ m. got
  • composition for adhesive layer An acrylic polymer obtained by copolymerizing 75 parts by mass of butyl acrylate (BA), 20 parts by mass of methyl methacrylate (MMA), and 5 parts by mass of 2-hydroxyethyl acrylate (2HEA) is added with all hydroxyl groups of the acrylic polymer.
  • 2-Methacryloyloxyethyl isocyanate (MOI) was reacted so as to be added to hydroxyl groups of 90 mol % of them to obtain an energy ray-curable acrylic resin (Mw: 500,000).
  • Example 2 A protective sheet for semiconductor processing was obtained in the same manner as in Example 1, except that a pressure-sensitive adhesive layer was formed using the following pressure-sensitive adhesive layer composition and the thickness of the antistatic layer was changed to 50 nm.
  • composition for adhesive layer An acrylic polymer obtained by copolymerizing 65 parts by mass of butyl acrylate (BA), 20 parts by mass of methyl methacrylate (MMA), and 15 parts by mass of 2-hydroxyethyl acrylate (2HEA) is added with all hydroxyl groups of the acrylic polymer.
  • 2-Methacryloyloxyethyl isocyanate (MOI) was reacted so as to be added to hydroxyl groups of 90 mol % of them to obtain an energy ray-curable acrylic resin (Mw: 500,000).
  • Example 3 A protective sheet for semiconductor processing was obtained in the same manner as in Example 1, except that the following adhesive layer composition was used to form the adhesive layer.
  • composition for adhesive layer An acrylic polymer obtained by copolymerizing 75 parts by mass of butyl acrylate (BA), 20 parts by mass of methyl methacrylate (MMA), and 5 parts by mass of 2-hydroxyethyl acrylate (2HEA) is added with all hydroxyl groups of the acrylic polymer.
  • 2-Methacryloyloxyethyl isocyanate (MOI) was reacted so as to be added to hydroxyl groups of 50 mol % of them to obtain an energy ray-curable acrylic resin (Mw: 500,000).
  • Example 1 The above measurements and evaluations were performed on the obtained samples (Examples 1 to 5 and Comparative Examples 1 to 3).
  • the adhesive force ratio was calculated from the 90° peeling adhesive force of the adhesive layer before and after energy ray curing. Table 1 shows the results.

Abstract

[Problem] To provide a protective sheet for semiconductor processing that sufficiently suppresses an electrostatic charge produced during processing of a wafer and suppresses cracking of chips during peel-off, even when the wafer is processed to be thin by DBG or similar, and to provide a semiconductor device manufacturing method in which said protective sheet for semiconductor processing is used. [Solution] A protective sheet for semiconductor processing, having: a substrate; an electrostatic charge prevention layer; an energy ray-curable adhesive layer; and a buffer layer, wherein the surface resistivity of the adhesive layer after energy ray curing is 5.1×1012 Ω/cm2 to 1.0×1015 Ω/cm2.

Description

半導体加工用保護シートおよび半導体装置の製造方法Protective sheet for semiconductor processing and method for manufacturing semiconductor device
　本発明は、半導体加工用保護シートおよび半導体装置の製造方法に関する。特に、ウエハの裏面研削を行い、その応力等でウエハを個片化する方法に好適に使用される半導体加工用保護シート、および、当該半導体加工用保護シートを用いる半導体装置の製造方法に関する。 The present invention relates to a protective sheet for semiconductor processing and a method for manufacturing a semiconductor device. In particular, the present invention relates to a protective sheet for semiconductor processing suitably used in a method of grinding the backside of a wafer and singulating the wafer by the stress of the wafer, and a method of manufacturing a semiconductor device using the protective sheet for semiconductor processing.
　各種電子機器の小型化、多機能化が進む中、それらに搭載される半導体チップも同様に、小型化、薄型化が求められている。チップの薄型化のために、半導体ウエハの裏面を研削して厚さ調整を行うことが一般的である。また、薄型化されたチップを得るために、ウエハの表面側から所定深さの溝をダイシングブレードにより形成した後、ウエハ裏面側から研削を行い、研削面を溝または溝近傍まで到達させてウエハを個片化し、チップを得る先ダイシング法（ＤＢＧ：Ｄｉｃｉｎｇ　Ｂｅｆｏｒｅ　Ｇｒｉｎｄｉｎｇ）と呼ばれる工法を利用することもある。ＤＢＧでは、ウエハの裏面研削と、ウエハの個片化を同時に行うことができるので、薄型チップを効率よく製造できる。 As various electronic devices become smaller and more functional, the semiconductor chips mounted on them are similarly required to be smaller and thinner. In order to make the chip thinner, it is common to grind the back surface of the semiconductor wafer to adjust the thickness. Further, in order to obtain a thinned chip, after forming grooves of a predetermined depth from the front side of the wafer with a dicing blade, grinding is performed from the rear side of the wafer so that the ground surface reaches the grooves or the vicinity of the grooves. are separated into individual chips to obtain chips, a method called DBG (Dicing Before Grinding) may be used. In the DBG, the backside grinding of the wafer and the singulation of the wafer can be performed at the same time, so thin chips can be manufactured efficiently.
　従来、半導体ウエハの裏面研削時や、ＤＢＧによるチップの製造時には、ウエハ表面の回路を保護し、また、半導体ウエハ及び半導体チップを保持するために、ウエハ表面にバックグラインドシートと呼ばれる粘着テープを貼付するのが一般的である。 Conventionally, when grinding the backside of a semiconductor wafer or manufacturing chips by DBG, an adhesive tape called a backgrind sheet is attached to the wafer surface to protect the circuits on the wafer surface and to hold the semiconductor wafer and semiconductor chips. It is common to
　バックグラインドシートの一例として、特許文献１および特許文献２には、ヤング率の高い基材と、基材の一方の面に緩衝層が設けられ、他方の面に粘着剤層が設けられた粘着テープが開示されている。 As an example of a back grind sheet, Patent Documents 1 and 2 disclose an adhesive having a base material with a high Young's modulus and a buffer layer provided on one side of the base material and an adhesive layer provided on the other side of the base material. A tape is disclosed.
　近年、ＤＢＧの変形例として、レーザーでウエハ内部に改質領域を設け、ウエハ裏面研削時の応力等でウエハの個片化を行う方法が提案されている。以下、この方法をＬＤＢＧ（Ｌａｓｅｒ　Ｄｉｃｉｎｇ　Ｂｅｆｏｒｅ　Ｇｒｉｎｄｉｎｇ）と記載することがある。ＬＤＢＧでは、ウエハは改質領域を起点として結晶方向に切断されるため、ダイシングブレードを用いたＤＢＧよりもチッピングの発生を低減できる。その結果、チップのさらなる薄型化に寄与できる。また、ダイシングブレードによりウエハ表面に所定深さの溝を形成するＤＢＧと比較して、ダイシングブレードによりウエハを削り取る領域がないため、つまり、カーフ幅が極小であるため、チップの収率に優れる。 In recent years, as a modified example of DBG, a method has been proposed in which a reformed region is provided inside the wafer with a laser, and the wafer is separated into individual pieces by using stress or the like during grinding of the backside of the wafer. Hereinafter, this method may be referred to as LDBG (Laser Dicing Before Grinding). In LDBG, the wafer is cut in the crystal direction starting from the modified region, so chipping can be reduced more than in DBG using a dicing blade. As a result, it can contribute to further thinning of the chip. In addition, compared to DBG in which grooves of a predetermined depth are formed on the wafer surface with a dicing blade, there is no region to be scraped off from the wafer by the dicing blade, that is, the kerf width is extremely small, resulting in excellent chip yield.
国際公開第２０１５／１５６３８９号WO2015/156389 特開２０１５－１８３００８号公報Japanese Unexamined Patent Application Publication No. 2015-183008
　ウエハの加工時（たとえば、ダイシング時、裏面研削時、洗浄時、バックグラインドテープの剥離時等）には、帯電が生じることが知られている。帯電が生じると、研削時に生じるカットダスト、環境に存在する微少な異物等がウエハまたは個片化されたチップに付着しやすくなる。 It is known that electrification occurs during wafer processing (for example, during dicing, backside grinding, cleaning, peeling back grind tape, etc.). When electrification occurs, cut dust generated during grinding and minute foreign matters present in the environment are likely to adhere to the wafer or the individualized chips.
　たとえば、裏面研削時にカットダストや異物がウエハに付着すると、裏面研削時の圧力が付着した異物等に集中し、異物等を起点としてウエハが破損することがある。特に、ウエハを薄く研削することを目的とするＤＢＧを行う場合には、わずかな圧力の集中によりウエハの破損が生じやすい。したがって、ウエハの加工時に生じる帯電を抑制する必要がある。 For example, if cut dust or foreign matter adheres to the wafer during backgrinding, the pressure during backgrinding concentrates on the adhering foreign matter, and the wafer may break starting from the foreign matter. In particular, when DBG is performed for the purpose of thinly grinding a wafer, the wafer is likely to be damaged by a slight concentration of pressure. Therefore, it is necessary to suppress electrification that occurs during wafer processing.
　また、バックグラインドテープは、ウエハの裏面研削時にはウエハの表面と強く接着して回路等を十分に保護し、裏面研削後に、ウエハからバックグラインドテープを剥離する際には、ウエハから容易に剥離することが求められる。そのため、ウエハに貼付されるバックグラインドテープの粘着剤層は、通常、エネルギー線硬化性の粘着剤から構成される。剥離時に、粘着剤層にエネルギー線を照射して硬化させ、粘着力を低下させることにより、裏面研削時の接着性と裏面研削後の剥離性との両立を図っている。 In addition, the backgrinding tape strongly adheres to the surface of the wafer when the backside of the wafer is ground to sufficiently protect the circuits, etc., and when the backgrinding tape is peeled off from the wafer after the backside grinding, the backgrinding tape is easily peeled off from the wafer. is required. Therefore, the pressure-sensitive adhesive layer of the backgrinding tape applied to the wafer is usually composed of an energy ray-curable pressure-sensitive adhesive. At the time of peeling, the pressure-sensitive adhesive layer is irradiated with energy rays to be cured and reduced in adhesive strength, thereby achieving both adhesion during back-grinding and releasability after back-grinding.
　しかしながら、エネルギー線照射による粘着剤層の硬化が不十分であると、剥離時に粘着剤がウエハ上に残存する、あるいは、剥離不良により個片化されたチップ同士が接触してチップの欠け、破損（以下、チップのクラックということもある）が発生することがある。特に、ＬＤＢＧでは、チップのカーフ幅が小さいため、僅かな剥離不良でもチップのクラックが発生することがある。 However, if the adhesive layer is not sufficiently cured by energy beam irradiation, the adhesive may remain on the wafer when peeled off, or chipping or breakage may occur due to contact between individualized chips due to poor peeling. (hereinafter also referred to as chip cracks) may occur. Especially in LDBG, since the kerf width of the chip is small, cracks may occur in the chip even with a slight peeling defect.
　特許文献１および特許文献２に記載のバックグラインドテープを、ＤＢＧ、特にＬＤＢＧにおいて使用した場合、ウエハの加工時に生じる帯電の抑制と、バックグラインドテープ剥離時のチップのクラックの発生の抑制とが不十分であるという問題があった。 When the backgrinding tapes described in Patent Documents 1 and 2 are used in DBG, especially LDBG, it is difficult to suppress electrification that occurs during wafer processing and to suppress chip cracking when the backgrinding tape is peeled off. There was a problem of enough.
　本発明は、このような実状に鑑みてなされ、ＤＢＧ等によりウエハを薄く加工する場合であっても、ウエハの加工時に生じる帯電が十分に抑制され、かつ剥離時にチップのクラックの発生が抑制されている半導体加工用保護シートを提供すること、および、当該半導体加工用保護シートを用いた半導体装置の製造方法を提供することを目的とする。 The present invention has been made in view of such circumstances, and even in the case where the wafer is processed to be thin by DBG or the like, the charging generated during processing of the wafer is sufficiently suppressed, and the cracking of the chip during separation is suppressed. It is an object of the present invention to provide a protective sheet for semiconductor processing that has a high degree of resistance, and to provide a method for manufacturing a semiconductor device using the protective sheet for semiconductor processing.
　本発明の態様は、以下の通りである。
　［１］基材と、帯電防止層と、エネルギー線硬化性の粘着剤層と、緩衝層と、を有し、
　エネルギー線硬化後の粘着剤層の表面抵抗率が５．１×１０１２Ω／ｃｍ２以上１．０×１０１５Ω／ｃｍ２以下である半導体加工用保護シートである。 Aspects of the present invention are as follows.
[1] having a substrate, an antistatic layer, an energy ray-curable adhesive layer, and a buffer layer,
The protective sheet for semiconductor processing has a surface resistivity of 5.1×10 12 Ω/cm 2 or more and 1.0×10 15 Ω/cm 2 or less after curing with energy rays.
　［２］エネルギー線硬化後の粘着剤層をシリコンウエハから剥離速度６００ｍｍ／分で粘着剤層とシリコンウエハとのなす角度が９０°となるように引き剥がした時の粘着力が０．１５Ｎ／２５ｍｍ未満である［１］に記載の半導体加工用保護シートである。 [2] When the adhesive layer after energy beam curing was peeled off from the silicon wafer at a peeling speed of 600 mm/min so that the angle between the adhesive layer and the silicon wafer was 90°, the adhesive strength was 0.15 N/. The protective sheet for semiconductor processing according to [1], which is less than 25 mm.
　［３］エネルギー線硬化前の粘着剤層をシリコンウエハから剥離速度６００ｍｍ／分で粘着剤層とシリコンウエハとのなす角度が９０°となるように引き剥がした時の粘着力に対して、エネルギー線硬化後の粘着剤層をシリコンウエハから剥離速度６００ｍｍ／分で粘着剤層とシリコンウエハとのなす角度が９０°となるように引き剥がした時の粘着力の比が、４％以下である［１］または［２］に記載の半導体加工用保護シートである。 [3] The adhesive force when the adhesive layer before energy beam curing is peeled off from the silicon wafer at a peeling speed of 600 mm / min so that the angle formed by the adhesive layer and the silicon wafer is 90 °. The adhesive strength ratio when the adhesive layer after linear curing is peeled off from the silicon wafer at a peeling speed of 600 mm/min so that the angle formed by the adhesive layer and the silicon wafer is 90° is 4% or less. The protective sheet for semiconductor processing according to [1] or [2].
　［４］基材のヤング率が１０００ＭＰａ以上である［１］から［３］のいずれかに記載の半導体加工用保護シートである。 [4] The protective sheet for semiconductor processing according to any one of [1] to [3], wherein the base material has a Young's modulus of 1000 MPa or more.
　［５］半導体加工用保護シートは、基材の一方の主面上に粘着剤層を有し、基材と粘着剤層との間に帯電防止層が設けられ、基材の他方の主面上に緩衝層が設けられている構成、または、基材の一方の主面上に粘着剤層を有し、基材と粘着剤層との間に帯電防止層および緩衝層が設けられている構成を有する［１］から［４］のいずれかに記載の半導体加工用保護シートである。 [5] A protective sheet for semiconductor processing has an adhesive layer on one main surface of a base material, an antistatic layer is provided between the base material and the adhesive layer, and the other main surface of the base material A structure in which a buffer layer is provided on top, or a structure in which an adhesive layer is provided on one main surface of a substrate, and an antistatic layer and a buffer layer are provided between the substrate and the adhesive layer The protective sheet for semiconductor processing according to any one of [1] to [4] having a structure.
　［６］表面に溝、または、内部に改質領域が形成されたウエハの裏面を研削することによりウエハをチップに個片化する工程において、ウエハの表面に貼付されて使用される［１］から［５］のいずれかに記載の半導体加工用保護シートである。 [6] Attached to the surface of the wafer and used in the process of singulating the wafer into chips by grinding the back surface of the wafer having grooves on the surface or a modified region formed inside [1] The protective sheet for semiconductor processing according to any one of [5] to [5].
　［７］［１］から［６］のいずれかに記載の半導体加工用保護シートを、ウエハの表面に貼付する工程と、
　ウエハの表面側から溝を形成する工程、または、ウエハの表面もしくは裏面からウエハ内部に改質領域を形成する工程と、
　半導体加工用保護シートが表面に貼付され、かつ溝または改質領域が形成されたウエハを、裏面側から研削して、溝または改質領域を起点として、複数のチップに個片化させる工程と、
　個片化されたチップから、半導体加工用保護シートを剥離する工程と、を有する半導体装置の製造方法である。 [7] A step of attaching the protective sheet for semiconductor processing according to any one of [1] to [6] to the surface of the wafer;
a step of forming a groove from the front surface side of the wafer, or a step of forming a modified region inside the wafer from the front surface or the rear surface of the wafer;
a step of grinding a wafer having a protective sheet for semiconductor processing adhered to its surface and having grooves or modified regions formed thereon from the back side, and singulating the wafer into a plurality of chips starting from the grooves or modified regions; ,
and peeling off a protective sheet for semiconductor processing from individualized chips.
　本発明によれば、ＤＢＧ等によりウエハを薄く加工する場合であっても、ウエハの加工時に生じる帯電が十分に抑制され、かつ剥離時にチップのクラックの発生が抑制されている半導体加工用保護シートを提供すること、および、当該半導体加工用保護シートを用いた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, even when a wafer is processed to be thin by DBG or the like, the protective sheet for semiconductor processing sufficiently suppresses electrification that occurs during wafer processing and suppresses chip cracking during peeling. and a method for manufacturing a semiconductor device using the protective sheet for semiconductor processing.
図１Ａは、本実施形態に係る半導体加工用保護シートの一例を示す断面模式図である。FIG. 1A is a schematic cross-sectional view showing an example of the protective sheet for semiconductor processing according to this embodiment. 図１Ｂは、本実施形態に係る半導体加工用保護シートの他の例を示す断面模式図である。FIG. 1B is a schematic cross-sectional view showing another example of the protective sheet for semiconductor processing according to this embodiment. 図２は、本実施形態に係る半導体加工用保護シートがウエハの回路面に貼付された様子を示す断面模式図である。FIG. 2 is a schematic cross-sectional view showing how the protective sheet for semiconductor processing according to this embodiment is attached to the circuit surface of the wafer.
　以下、本発明を、具体的な実施形態に基づき、図面を用いて詳細に説明する。まず、本明細書で使用する主な用語を説明する。 Hereinafter, the present invention will be described in detail based on specific embodiments with reference to the drawings. First, major terms used in this specification will be explained.
　ウエハの個片化は、ウエハを回路毎に分割しチップを得ることを言う。 Wafer singulation refers to dividing the wafer into individual circuits to obtain chips.
　ウエハの「表面」は、回路、電極等が形成された面を指し、ウエハの「裏面」は、回路等が形成されていない面を指す。 The "front surface" of the wafer refers to the surface on which circuits, electrodes, etc. are formed, and the "back surface" of the wafer refers to the surface on which circuits, etc. are not formed.
　ＤＢＧ（Ｄｉｃｉｎｇ　Ｂｅｆｏｒｅ　Ｇｒｉｎｄｉｎｇ）は、ウエハの表面側に所定深さの溝を形成した後、ウエハ裏面側から研削を行い、研削によりウエハを個片化する方法を言う。ウエハの表面側に形成される溝は、ブレードダイシング、レーザーダイシングやプラズマダイシングなどの方法により形成される。 DBG (Dicing Before Grinding) refers to a method of forming grooves of a predetermined depth on the front side of a wafer, grinding the back side of the wafer, and singulating the wafer by grinding. The grooves formed on the surface side of the wafer are formed by a method such as blade dicing, laser dicing or plasma dicing.
　また、ＬＤＢＧ（Ｌａｓｅｒ　Ｄｉｃｉｎｇ　Ｂｅｆｏｒｅ　Ｇｒｉｎｄｉｎｇ）は、ＤＢＧの変形例であり、レーザーでウエハ内部に改質領域を設け、ウエハ裏面研削時の応力等でウエハの個片化を行う方法を言う。 In addition, LDBG (Laser Dicing Before Grinding) is a modification of DBG, and refers to a method in which a modified region is provided inside the wafer with a laser, and the wafer is separated into individual pieces by stress or the like during wafer backside grinding.
　「チップ群」は、ウエハの個片化後に、本実施形態に係る半導体加工用保護シート上に保持されている複数のチップをいう。これらのチップは、全体として、ウエハの形状と同様の形状を構成する。 "Chip group" refers to a plurality of chips held on the protective sheet for semiconductor processing according to the present embodiment after singulation of the wafer. These chips collectively form a shape similar to that of the wafer.
　「（メタ）アクリレート」は、「アクリレート」および「メタクリレート」の双方を示す語として用いており、他の類似用語についても同様である。 "(Meth)acrylate" is used as a term to indicate both "acrylate" and "methacrylate", and the same applies to other similar terms.
　「エネルギー線」は、紫外線、電子線等を指し、好ましくは紫外線である。 "Energy rays" refer to ultraviolet rays, electron rays, etc., preferably ultraviolet rays.
　「重量平均分子量」は、特に断りのない限り、ゲル・パーミエーション・クロマトグラフィー（ＧＰＣ）法により測定されるポリスチレン換算値である。このような方法による測定は、たとえば、東ソー社製の高速ＧＰＣ装置「ＨＬＣ－８１２０ＧＰＣ」に、高速カラム「ＴＳＫ ｇｕａｒｄ ｃｏｌｕｍｎ ＨXL－Ｈ」、「ＴＳＫ Ｇｅｌ ＧＭＨXL」、「ＴＳＫ Ｇｅｌ Ｇ２０００ ＨXL」（以上、全て東ソー社製）をこの順序で連結したものを用い、カラム温度：４０℃、送液速度：１.０ｍＬ／分の条件で、検出器を示差屈折率計として行われる。 "Weight average molecular weight" is a polystyrene conversion value measured by a gel permeation chromatography (GPC) method unless otherwise specified. Measurement by such a method can be carried out, for example, on a high-speed GPC apparatus "HLC-8120GPC" manufactured by Tosoh Corporation, using high-speed columns "TSK guard column H XL -H", "TSK Gel GMH XL ", and "TSK Gel G2000 H XL ". (all manufactured by Tosoh Corporation) in this order, column temperature: 40° C., liquid feed rate: 1.0 mL/min, and a differential refractometer as a detector.
　（１．半導体加工用保護シート）
　本実施形態に係る半導体加工用保護シート１は、図１Ａに示すように、基材１０の一方の主面１０ａ上に帯電防止層２０および粘着剤層３０がこの順に設けられ、基材１０の他方の主面１０ｂ上に緩衝層４０が設けられた構成を有している。帯電防止機能の観点からは、帯電防止層は、半導体加工用保護シートの剥離界面、すなわち、粘着剤層の表面３０ａに近い方が好ましい。したがって、図１Ａに示すように、帯電防止層２０は、基材１０の他方の主面１０ｂ上に設けられるよりも、基材１０の一方の主面１０ａ上に設けられることが好ましい。半導体加工用保護シート１の使用時には、粘着剤層３０の表面３０ａが被着体に一時的に貼付され、その後被着体から剥離される。 (1. Protective sheet for semiconductor processing)
As shown in FIG. 1A, the protective sheet for semiconductor processing 1 according to the present embodiment has an antistatic layer 20 and an adhesive layer 30 provided in this order on one main surface 10a of a substrate 10. It has a configuration in which a buffer layer 40 is provided on the other main surface 10b. From the viewpoint of the antistatic function, the antistatic layer is preferably close to the peeling interface of the protective sheet for semiconductor processing, that is, the surface 30a of the pressure-sensitive adhesive layer. Therefore, as shown in FIG. 1A, antistatic layer 20 is preferably provided on one main surface 10a of substrate 10 rather than on the other main surface 10b of substrate 10. FIG. When the protective sheet for semiconductor processing 1 is used, the surface 30a of the pressure-sensitive adhesive layer 30 is temporarily attached to an adherend and then peeled off from the adherend.
　半導体加工用保護シートは、図１Ａに記載の構成に限定されない。たとえば、図１Ｂに示すように、半導体加工用保護シート１は、基材１０の一方の主面１０ａ上に帯電防止層２０、粘着剤層３０および緩衝層４０が設けられていてもよい。帯電防止層２０および緩衝層４０は、基材１０と粘着剤層３０との間に配置されている。半導体加工用保護シートの製造の容易さの観点からは、図１Ｂに示すように、基材１０上に、帯電防止層２０、緩衝層４０および粘着剤層３０がこの順で配置されていることが好ましい。一方、上述したように、帯電防止機能の観点からは、基材１０上に、緩衝層４０、帯電防止層２０および粘着剤層３０がこの順で配置されていることが好ましい。 The protective sheet for semiconductor processing is not limited to the configuration shown in FIG. 1A. For example, as shown in FIG. 1B, the protective sheet for semiconductor processing 1 may be provided with an antistatic layer 20, an adhesive layer 30 and a buffer layer 40 on one main surface 10a of the substrate 10. FIG. The antistatic layer 20 and the buffer layer 40 are arranged between the substrate 10 and the adhesive layer 30 . From the viewpoint of ease of manufacturing the protective sheet for semiconductor processing, as shown in FIG. is preferred. On the other hand, as described above, from the viewpoint of the antistatic function, it is preferable that the buffer layer 40, the antistatic layer 20 and the adhesive layer 30 are arranged in this order on the substrate 10.
　また、本発明の効果が得られる限りにおいて、半導体加工用保護シートは他の層を有していてもよい。すなわち、半導体加工用保護シートが、基材、帯電防止層、緩衝層および粘着剤層を有していれば、たとえば、基材と緩衝層との間に他の層が形成されていてもよいし、基材と帯電防止層との間に他の層が形成されていてもよい。 In addition, the protective sheet for semiconductor processing may have other layers as long as the effects of the present invention can be obtained. That is, as long as the protective sheet for semiconductor processing has a substrate, an antistatic layer, a buffer layer and an adhesive layer, other layers may be formed between the substrate and the buffer layer, for example. However, another layer may be formed between the substrate and the antistatic layer.
　以下では、半導体加工用保護シートが図１Ａに示す構成を有している場合について説明する。 In the following, the case where the protective sheet for semiconductor processing has the configuration shown in FIG. 1A will be described.
　図２に示すように、被着体としてのウエハ１００の回路面、すなわち、ウエハ１００の表面１００ａに、粘着剤層の表面３０ａが貼付されることにより、本実施形態に係る半導体加工用保護シート１はウエハ１００の裏面１００ｂを研削する際にウエハ１００の表面１００ａを保護する。 As shown in FIG. 2, the surface 30a of the adhesive layer is attached to the circuit surface of the wafer 100 as an adherend, that is, the surface 100a of the wafer 100, whereby the protective sheet for semiconductor processing according to the present embodiment is formed. 1 protects the front surface 100a of the wafer 100 when the rear surface 100b of the wafer 100 is ground.
　上述したように、裏面研削を含むウエハの加工時にはウエハまたはチップ群に帯電が生じる。このような帯電が緩和されない場合、帯電に起因するウエハ等への異物等の付着を招き、ウエハ等の破損が生じる恐れがある。そこで、本実施形態に係る半導体加工用保護シートは、帯電防止層を含み、かつ粘着剤層の表面抵抗率を所定の範囲とすることにより、帯電圧を下げ、静電気を緩和している。 As described above, electrification occurs on the wafer or chip group during wafer processing including backside grinding. If such electrification is not relieved, there is a risk that foreign matter or the like will adhere to the wafer or the like due to the electrification, resulting in damage to the wafer or the like. Therefore, the protective sheet for semiconductor processing according to the present embodiment includes an antistatic layer and the pressure-sensitive adhesive layer has a surface resistivity within a predetermined range, thereby lowering the charged voltage and alleviating static electricity.
　また、本発明者は、粘着剤層の表面抵抗率が、エネルギー線照射後の粘着剤層の硬化の程度を反映していることを見出した。硬化前の粘着剤層中のエネルギー線重合性の炭素－炭素二重結合量が多くなると、粘着剤層の硬化が進みやすく、硬化後の粘着剤層中の架橋点が増えるので、電荷が動きづらくなり表面抵抗率が高くなる傾向にある。一方、硬化前の粘着剤層中のエネルギー線重合性の炭素－炭素二重結合量が少なくなると、表面抵抗率は低くなる傾向があるものの、重合反応の起点が少なくなるので、粘着剤層の硬化が不十分になりやすい。その結果、ウエハ等から半導体加工用保護シートを剥離する際に、粘着剤層の剥離不良が発生し、ウエハ等の破損、クラック等が発生する傾向にある。そこで、本実施形態では、たとえば、硬化前の粘着剤層中のエネルギー線重合性の炭素－炭素二重結合量を制御することにより、粘着剤層の組成をエネルギー線照射により十分に硬化する組成としつつ、粘着剤層の表面抵抗率を所定の範囲に制御して、帯電を緩和し、かつ粘着剤層の剥離不良に起因するウエハ等の破損、クラック等を抑制している。 The inventor also found that the surface resistivity of the pressure-sensitive adhesive layer reflects the degree of curing of the pressure-sensitive adhesive layer after irradiation with energy rays. When the amount of energy ray-polymerizable carbon-carbon double bonds in the pressure-sensitive adhesive layer before curing increases, the pressure-sensitive adhesive layer cures more easily, and the number of cross-linking points in the pressure-sensitive adhesive layer after curing increases, so electric charges move. becomes difficult and the surface resistivity tends to increase. On the other hand, when the amount of energy ray-polymerizable carbon-carbon double bonds in the pressure-sensitive adhesive layer before curing decreases, the surface resistivity tends to decrease, but the number of starting points for the polymerization reaction decreases. Hardening tends to be insufficient. As a result, when the protective sheet for semiconductor processing is peeled off from the wafer or the like, the peeling failure of the adhesive layer tends to occur, and the wafer or the like tends to be damaged or cracked. Therefore, in the present embodiment, for example, by controlling the amount of energy ray-polymerizable carbon-carbon double bonds in the pressure-sensitive adhesive layer before curing, the composition of the pressure-sensitive adhesive layer is sufficiently cured by energy ray irradiation. At the same time, the surface resistivity of the adhesive layer is controlled within a predetermined range to alleviate electrification and to suppress breakage, cracks, etc. of wafers and the like caused by poor peeling of the adhesive layer.
　以下、半導体加工用保護シートの構成要素について詳細に説明する。 The constituent elements of the protective sheet for semiconductor processing will be described in detail below.
　（２．基材）
　基材は、ウエハの裏面研削前にウエハを支持でき、裏面研削後のウエハ等を保持できる材料で構成されていれば制限されない。たとえば、基材として、バックグラインドテープの基材として使用されている各種の樹脂フィルムが例示される。基材は、１つの樹脂フィルムからなる単層フィルムから構成されていてもよいし、複数の樹脂フィルムが積層された複層フィルムから構成されていてもよい。 (2. Base material)
The substrate is not limited as long as it is made of a material that can support the wafer before the back surface of the wafer is ground and that can hold the wafer after the back surface is ground. For example, the base material includes various resin films used as base materials for back grind tapes. The substrate may be composed of a single-layer film made of one resin film, or may be composed of a multi-layer film in which a plurality of resin films are laminated.
　（２．１　基材の物性）
　本実施形態では、基材は剛性が高いことが好ましい。基材の剛性が高いことにより、裏面研削時の振動等を抑制でき、その結果、ウエハ等の支持および保持性能が向上し、ウエハ等の破損やクラックが低減される。また、半導体加工用保護シートをウエハ等から剥離する際の応力を小さくすることが可能になり、剥離時に生じるウエハ等の破損やクラックが低減される。さらに、半導体加工用保護シートをウエハに貼付する際の作業性も良好になる。具体的には、基材の２３℃におけるヤング率は、１０００ＭＰａ以上であることが好ましく、１８００ＭＰａ以上であることがより好ましい。ヤング率の上限は特に制限されないが、３００００ＭＰａ程度である。 (2.1 Physical properties of base material)
In this embodiment, the substrate preferably has high rigidity. The high rigidity of the base material makes it possible to suppress vibration and the like during back-grinding. In addition, it becomes possible to reduce the stress when the protective sheet for semiconductor processing is peeled off from the wafer or the like, thereby reducing the breakage or cracks of the wafer or the like occurring at the time of peeling. Furthermore, workability is improved when the protective sheet for semiconductor processing is attached to the wafer. Specifically, the Young's modulus of the substrate at 23° C. is preferably 1000 MPa or more, more preferably 1800 MPa or more. Although the upper limit of Young's modulus is not particularly limited, it is about 30000 MPa.
　基材の厚さは、本実施形態では、１５μｍ以上１１０μｍ以下であることが好ましく、２０μｍ以上１０５μｍ以下であることがより好ましい。 In this embodiment, the thickness of the base material is preferably 15 μm or more and 110 μm or less, more preferably 20 μm or more and 105 μm or less.
　（２．２　基材の材質）
　基材の材質としては、基材のヤング率が上記の範囲内となるように材料を選択すればよい。本実施形態では、たとえば、ポリエチレンテレフタレート、ポリエチレンナフタレート、ポリブチレンテレフタレート、全芳香族ポリエステル等のポリエステル、ポリイミド、ポリアミド、ポリカーボネート、ポリアセタール、変性ポリフェニレンオキシド、ポリフェニレンスルフィド、ポリスルホン、ポリエーテルケトン、二軸延伸ポリプロピレン等が挙げられる。これらの中でも、ポリエステル、ポリアミド、ポリイミド、二軸延伸ポリプロピレンから選ばれる１種以上であることが好ましく、ポリエステルであることがより好ましく、ポリエチレンテレフタレートであることがさらに好ましい。 (2.2 Material of base material)
The material of the substrate may be selected so that the Young's modulus of the substrate is within the above range. In the present embodiment, for example, polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, polyester such as wholly aromatic polyester, polyimide, polyamide, polycarbonate, polyacetal, modified polyphenylene oxide, polyphenylene sulfide, polysulfone, polyether ketone, biaxially oriented A polypropylene etc. are mentioned. Among these, one or more selected from polyester, polyamide, polyimide, and biaxially oriented polypropylene is preferable, polyester is more preferable, and polyethylene terephthalate is further preferable.
　また、基材は、本発明の効果を損なわない範囲において、可塑剤、滑剤、赤外線吸収剤、紫外線吸収剤、フィラー、着色剤、帯電防止剤、酸化防止剤、触媒等を含んでもよい。また、基材は、透明なものであっても、不透明なものであってもよく、所望により着色ま
たは蒸着されていてもよい。 The substrate may also contain plasticizers, lubricants, infrared absorbers, ultraviolet absorbers, fillers, colorants, antistatic agents, antioxidants, catalysts, etc., as long as the effects of the present invention are not impaired. Also, the substrate may be transparent or opaque, and may be colored or vapor-deposited as desired.
　また、基材の少なくとも一方の主面には、他の層との密着性を向上させるために、コロナ処理等の接着処理を施してもよい。また、基材は、主面の少なくとも一方にプライマー層を有してもよい。 In addition, at least one main surface of the base material may be subjected to adhesion treatment such as corona treatment in order to improve adhesion with other layers. Also, the base material may have a primer layer on at least one of its main surfaces.
　プライマー層を形成するプライマー層形成用組成物としては、特に限定されないが、例えば、ポリエステル系樹脂、ウレタン系樹脂、ポリエステルウレタン系樹脂、アクリル系樹脂等を含む組成物が挙げられる。プライマー層形成用組成物には、必要に応じて、架橋剤、光重合開始剤、酸化防止剤、軟化剤（可塑剤）、充填剤、防錆剤、顔料、染料等を含有してもよい。 The primer layer-forming composition for forming the primer layer is not particularly limited, but examples thereof include compositions containing polyester-based resins, urethane-based resins, polyester-urethane-based resins, acrylic-based resins, and the like. The primer layer-forming composition may optionally contain a cross-linking agent, a photopolymerization initiator, an antioxidant, a softening agent (plasticizer), a filler, an antirust agent, a pigment, a dye, and the like. .
　プライマー層の厚さは、好ましくは０．０１～１０μｍ、より好ましくは０．０３～５μｍである。プライマー層の材質は柔らかいため、ヤング率に与える影響は小さく、基材のヤング率は、プライマー層を有する場合でも、樹脂フィルムのヤング率と実質的に同一である。 The thickness of the primer layer is preferably 0.01-10 μm, more preferably 0.03-5 μm. Since the material of the primer layer is soft, it has little effect on the Young's modulus, and the Young's modulus of the substrate is substantially the same as that of the resin film even when the primer layer is provided.
　例えば、基材のヤング率は、樹脂組成の選択、可塑剤の添加、樹脂フィルム製造時の延伸条件などにより制御できる。 For example, the Young's modulus of the base material can be controlled by selecting the resin composition, adding a plasticizer, and stretching conditions during resin film production.
　（３．粘着剤層）
　粘着剤層は、半導体ウエハの回路面に貼付され、回路面から剥離されるまで、回路面を保護し、半導体ウエハを支持する。本実施形態では、粘着剤層はエネルギー線硬化性である。粘着剤層は１層（単層）から構成されていてもよいし、２層以上の複数層から構成されていてもよい。粘着剤層が複数層を有する場合、これら複数層は、互いに同一でも異なっていてもよく、これら複数層を構成する層の組み合わせは特に制限されない。 (3. Adhesive layer)
The adhesive layer is attached to the circuit surface of the semiconductor wafer, protects the circuit surface, and supports the semiconductor wafer until it is peeled off from the circuit surface. In this embodiment, the pressure-sensitive adhesive layer is energy ray-curable. The pressure-sensitive adhesive layer may be composed of one layer (single layer), or may be composed of multiple layers of two or more layers. When the pressure-sensitive adhesive layer has multiple layers, these multiple layers may be the same or different, and the combination of layers constituting these multiple layers is not particularly limited.
　粘着剤層の厚さは、特に制限されないが、好ましくは３μｍ以上２００μｍ以下、より好ましくは５μｍ以上１００μｍ以下である。粘着剤層の厚さが上記の範囲内であることにより、ウエハの割れやチップの移動を抑制することができる。 Although the thickness of the adhesive layer is not particularly limited, it is preferably 3 µm or more and 200 µm or less, more preferably 5 µm or more and 100 µm or less. When the thickness of the adhesive layer is within the above range, cracking of the wafer and movement of the chips can be suppressed.
　なお、粘着剤層の厚さは、粘着剤層全体の厚さを意味する。たとえば、複数層から構成される粘着剤層の厚さは、粘着剤層を構成するすべての層の合計の厚さを意味する。 The thickness of the adhesive layer means the thickness of the entire adhesive layer. For example, the thickness of a pressure-sensitive adhesive layer composed of multiple layers means the total thickness of all layers constituting the pressure-sensitive adhesive layer.
　本実施形態では、粘着剤層は以下の物性を有している。 In this embodiment, the adhesive layer has the following physical properties.
　（３．１　表面抵抗率）
　本実施形態では、エネルギー線硬化後の粘着剤層の表面抵抗率が５．１×１０１２Ω／ｃｍ２以上１．０×１０１５Ω／ｃｍ２以下である。なお、この表面抵抗率は、粘着剤層の表面のうち、被着体に貼付される面（図１Ａでは、粘着剤層の表面３０ａ）における表面抵抗率である。 (3.1 Surface resistivity)
In this embodiment, the surface resistivity of the adhesive layer after energy ray curing is 5.1×10 12 Ω/cm 2 or more and 1.0×10 15 Ω/cm 2 or less. This surface resistivity is the surface resistivity of the surface of the adhesive layer that is attached to the adherend (the surface 30a of the adhesive layer in FIG. 1A).
　表面抵抗率が上記の範囲内であることにより、半導体加工用保護シートから静電気が逃げやすくなり、半導体加工用保護シートが貼付されているウエハの加工時にウエハまたはチップ群が帯電することを抑制することができる。したがって、ウエハの表面に半導体加工用保護シートを貼付する工程、ウエハの裏面を研削する工程、半導体加工用保護シートを剥離する工程、半導体加工用保護シートの剥離後のウエハまたはチップ群の搬送工程等において、ウエハ等に異物等が付着することを抑制することができる。その結果、異物等の付着に起因するウエハ等の破損、クラックが抑制される。 When the surface resistivity is within the above range, static electricity easily escapes from the protective sheet for semiconductor processing, and the wafer or chip group is suppressed from being charged during processing of the wafer to which the protective sheet for semiconductor processing is attached. be able to. Therefore, the steps of attaching a protective sheet for semiconductor processing to the front surface of the wafer, grinding the back surface of the wafer, peeling off the protective sheet for semiconductor processing, and transferring the wafer or chip group after peeling off the protective sheet for semiconductor processing. , etc., it is possible to suppress adhesion of foreign matter or the like to the wafer or the like. As a result, breakage and cracking of the wafer or the like due to adhesion of foreign matter or the like is suppressed.
　また、表面抵抗率が上記の範囲内であることにより、半導体加工用保護シートを剥離しても、個片化されたチップの移動が抑制され、チップ同士の接触が低減されるため、チップのクラックを抑制することができる。上述したように、表面抵抗率は、硬化前の粘着剤層中のエネルギー線重合性の炭素－炭素二重結合量によりある程度制御でき、粘着剤層の硬化が進むと、表面抵抗率が高くなる傾向にある。したがって、表面抵抗率が上記の範囲よりも小さい場合には、粘着剤層の硬化が不十分である。その結果、半導体加工用保護シートの剥離時に、ウエハまたはチップから良好に剥離せずに、粘着剤層の一部がウエハまたはチップに付着したままとなったり（糊残り）、チップのクラックを招くことがある。 In addition, since the surface resistivity is within the above range, even if the protective sheet for semiconductor processing is peeled off, the movement of the separated chips is suppressed and the contact between the chips is reduced. Cracks can be suppressed. As described above, the surface resistivity can be controlled to some extent by the amount of energy ray-polymerizable carbon-carbon double bonds in the pressure-sensitive adhesive layer before curing, and as the pressure-sensitive adhesive layer is cured, the surface resistivity increases. There is a tendency. Therefore, when the surface resistivity is smaller than the above range, the curing of the pressure-sensitive adhesive layer is insufficient. As a result, when the protective sheet for semiconductor processing is peeled off from the wafer or chip, a part of the adhesive layer remains attached to the wafer or chip (adhesive residue), or the chip cracks. Sometimes.
　表面抵抗率は９．５×１０１４Ω／ｃｍ２以下であることが好ましく、９．０×１０１４Ω／ｃｍ２以下であることがより好ましい。一方、表面抵抗率は５．２×１０１２Ω／ｃｍ２以上であることが好ましく、５．５×１０１２Ω／ｃｍ２以上であることがより好ましい。 The surface resistivity is preferably 9.5×10 14 Ω/cm 2 or less, more preferably 9.0×10 14 Ω/cm 2 or less. On the other hand, the surface resistivity is preferably 5.2×10 12 Ω/cm 2 or higher, more preferably 5.5×10 12 Ω/cm 2 or higher.
　本実施形態では、表面抵抗率はＪＩＳ　Ｋ　７１９４に準じて測定される。すなわち、ＪＩＳ　Ｋ　７１９４に規定されている測定方法と同様に測定するが、測定条件が異なっていてもよい。具体的な測定条件は実施例において後述する。 In this embodiment, surface resistivity is measured according to JIS K 7194. That is, the measurement is performed in the same manner as the measurement method specified in JIS K 7194, but the measurement conditions may be different. Specific measurement conditions will be described later in Examples.
　（３．２　エネルギー線硬化後の粘着剤層の９０°引き剥がし粘着力）
　本実施形態では、エネルギー線硬化後の粘着剤層をシリコンウエハから粘着剤層とシリコンウエハとのなす角度が９０°となるように引き剥がした時の粘着力（以降、エネルギー線硬化後の粘着剤層の９０°引き剥がし粘着力ともいう）が０．１５Ｎ／２５ｍｍ未満であることが好ましい。エネルギー線硬化後の粘着剤層の９０°引き剥がし粘着力が上記の範囲内であることにより、粘着力が十分に低下しているため、裏面研削後のチップ群から粘着剤層の剥離が容易になる。したがって、ウエハ等への糊残りやチップのクラックを低減することができる。 (3.2 90° peeling adhesive strength of adhesive layer after energy beam curing)
In the present embodiment, the adhesive strength when the adhesive layer after energy ray curing is peeled off from the silicon wafer so that the angle between the adhesive layer and the silicon wafer is 90° (hereinafter referred to as the adhesive after energy ray curing The 90° peeling adhesive strength of the agent layer) is preferably less than 0.15 N/25 mm. When the 90° peeling adhesive force of the adhesive layer after energy beam curing is within the above range, the adhesive force is sufficiently reduced, so the adhesive layer can be easily peeled off from the chip group after backside grinding. become. Therefore, it is possible to reduce adhesive residue on wafers and cracks in chips.
　エネルギー線硬化後の粘着剤層の９０°引き剥がし粘着力は０．１４Ｎ／２５ｍｍ以下であることがより好ましく、０．１３Ｎ／２５ｍｍ以下であることがさらに好ましい。一方、エネルギー線硬化後の粘着剤層の９０°引き剥がし粘着力が小さすぎると、所定のテープ剥離工程より前に予期せぬタイミングでテープが剥離してしまい、プロセスエラーが発生してしまう可能性がある。したがって、エネルギー線硬化後の粘着剤層の９０°引き剥がし粘着力は、０．０３５Ｎ／２５ｍｍ以上であることが好ましい。 The 90° peeling adhesive strength of the adhesive layer after energy ray curing is more preferably 0.14 N/25 mm or less, more preferably 0.13 N/25 mm or less. On the other hand, if the 90° peeling adhesive strength of the adhesive layer after energy beam curing is too small, the tape may peel off at an unexpected timing before the predetermined tape peeling process, resulting in process errors. have a nature. Therefore, the 90° peeling adhesive strength of the adhesive layer after energy ray curing is preferably 0.035 N/25 mm or more.
　本実施形態では、エネルギー線硬化後の粘着剤層の９０°引き剥がし粘着力は、ＪＩＳ　Ｚ　０２３７に準じて、粘着剤層をシリコンウエハに貼付して、エネルギー線により粘着剤層を硬化した後、剥離速度６００ｍｍ／分の条件でシリコンウエハから硬化後の粘着剤層を９０°の角度で引き剥がした時の粘着力を測定する。具体的な測定条件は実施例において後述する。 In this embodiment, the 90° peeling adhesive strength of the pressure-sensitive adhesive layer after curing with energy rays is determined according to JIS Z 0237 after the pressure-sensitive adhesive layer is attached to a silicon wafer and the pressure-sensitive adhesive layer is cured with energy rays. , the adhesive strength when the adhesive layer after curing is peeled off from the silicon wafer at an angle of 90° at a peeling speed of 600 mm/min. Specific measurement conditions will be described later in Examples.
　なお、６００ｍｍ／分という剥離速度は、通常の粘着力測定時の剥離速度よりも速い傾向にある。この条件は、ＤＢＧ、ＬＤＢＧにより研削されたウエハ等から粘着剤層を剥離する際の剥離速度を想定している。剥離速度が大きくなると、一般的に、粘着力は大きくなる傾向にある。 It should be noted that the peeling speed of 600 mm/min tends to be faster than the peeling speed during normal adhesion measurement. This condition assumes the peeling speed at the time of peeling off the adhesive layer from a wafer or the like ground by DBG or LDBG. As the peel speed increases, the adhesive strength generally tends to increase.
　（３．３　エネルギー線硬化前後の粘着剤層の９０°引き剥がし粘着力比）
　本実施形態では、エネルギー線硬化前後の粘着剤層の９０°引き剥がし粘着力の比は、４％以下であることが好ましい。すなわち、エネルギー線硬化前の粘着剤層をシリコンウエハから粘着剤層とシリコンウエハとのなす角度が９０°となるように引き剥がした時の粘着力（以降、エネルギー線硬化前の粘着剤層の９０°引き剥がし粘着力ともいう）に対する、エネルギー線硬化後の粘着剤層の９０°引き剥がし粘着力の比（以降、粘着力比ともいう）が４％以下であることが好ましい。 (3.3 90° peeling adhesive force ratio of adhesive layer before and after energy beam curing)
In this embodiment, the ratio of the 90° peeling adhesive strength of the adhesive layer before and after energy ray curing is preferably 4% or less. That is, the adhesive strength when the adhesive layer before energy beam curing is peeled off from the silicon wafer so that the angle between the adhesive layer and the silicon wafer is 90° (hereinafter referred to as the adhesive layer before energy beam curing The ratio of the 90° peeling adhesive strength of the adhesive layer after energy beam curing (hereinafter also referred to as the adhesive strength ratio) to the 90° peeling adhesive strength is preferably 4% or less.
　粘着力比が上記の範囲内であることにより、裏面研削時には、ウエハの表面に粘着剤層が十分吸着して回路を保護するとともに、裏面研削後には、ウエハ等からの粘着剤層の剥離が容易となり、チップのクラックを抑制することができる。 When the adhesive force ratio is within the above range, the adhesive layer sufficiently adheres to the surface of the wafer to protect the circuit during back-grinding, and the adhesive layer does not peel off from the wafer, etc. after back-grinding. It becomes easy and the crack of a chip|tip can be suppressed.
　粘着力比は３％以下であることがより好ましく、２％以下であることがさらに好ましい。一方、粘着力比の下限は特に制限されないが、通常、０．３％程度である。 The adhesive strength ratio is more preferably 3% or less, and even more preferably 2% or less. On the other hand, although the lower limit of the adhesive force ratio is not particularly limited, it is usually about 0.3%.
　エネルギー線硬化前の粘着剤層の９０°引き剥がし粘着力は、エネルギー線硬化前の粘着剤層の粘着力を測定する以外は、エネルギー線硬化後の粘着剤層の９０°引き剥がし粘着力の測定方法と同一にすればよい。具体的な測定条件は実施例において後述する。 The 90° peeling adhesive strength of the pressure-sensitive adhesive layer before curing with energy rays is the 90° peeling strength of the pressure-sensitive adhesive layer after curing with energy rays, except for measuring the adhesive strength of the pressure-sensitive adhesive layer before curing with energy rays. It should be the same as the measurement method. Specific measurement conditions will be described later in Examples.
　（３．４　粘着剤層の組成）
　粘着剤層の組成は、粘着剤層がウエハの回路面を保護できる程度の粘着性を有し、かつ上記の表面抵抗率を有していれば特に制限されない。本実施形態では、粘着剤層は、粘着性を発現し得る粘着剤成分（粘着性樹脂）として、たとえば、アクリル系粘着剤、ウレタン系粘着剤、ゴム系粘着剤、シリコーン系粘着剤等を含む組成物（粘着剤層用組成物）から構成されることが好ましい。 (3.4 Composition of adhesive layer)
The composition of the pressure-sensitive adhesive layer is not particularly limited as long as the pressure-sensitive adhesive layer has adhesiveness to the extent that it can protect the circuit surface of the wafer and has the surface resistivity described above. In the present embodiment, the pressure-sensitive adhesive layer contains, for example, an acrylic pressure-sensitive adhesive, a urethane-based pressure-sensitive adhesive, a rubber-based pressure-sensitive adhesive, a silicone-based pressure-sensitive adhesive, etc., as a pressure-sensitive adhesive component (adhesive resin) capable of expressing pressure-sensitive adhesiveness. It is preferably composed of a composition (composition for pressure-sensitive adhesive layer).
　また、上記のエネルギー線硬化後の粘着力および粘着力比を実現しやすいという観点から、粘着剤層用組成物はエネルギー線硬化性粘着剤を含む。 In addition, the composition for the adhesive layer contains an energy ray-curable adhesive from the viewpoint of easily achieving the adhesive strength and adhesive strength ratio after energy ray curing.
　（３．５　粘着剤層用組成物）
　上述したように、粘着剤層はエネルギー線硬化性であるので、エネルギー線硬化性を有する組成物（粘着剤層用組成物）から形成される。以下では、粘着剤層用組成物について説明する。 (3.5 Composition for adhesive layer)
As described above, since the pressure-sensitive adhesive layer is energy ray-curable, it is formed from an energy ray-curable composition (composition for pressure-sensitive adhesive layer). Below, the composition for adhesive layers is demonstrated.
　粘着剤層用組成物は、粘着性樹脂とは別にエネルギー線硬化性化合物が配合されることでエネルギー線硬化性を有してもよいが、上記した粘着性樹脂自体がエネルギー線硬化性を有することが好ましい。粘着性樹脂自体がエネルギー線硬化性を有する場合、粘着性樹脂にエネルギー線重合性基が導入されるが、エネルギー線重合性基は粘着性樹脂の主鎖または側鎖に導入されることが好ましい。 The composition for the pressure-sensitive adhesive layer may have energy ray-curable properties by blending an energy ray-curable compound separately from the adhesive resin, but the adhesive resin itself has energy ray-curable properties. is preferred. When the adhesive resin itself has energy ray curability, an energy ray polymerizable group is introduced into the adhesive resin, and the energy ray polymerizable group is preferably introduced into the main chain or side chain of the adhesive resin. .
　また、粘着性樹脂とは別にエネルギー線硬化性化合物が配合される場合、そのエネルギー線硬化性化合物としては、エネルギー線重合性基を有するモノマー、オリゴマーが使用される。オリゴマーは、重量平均分子量（Ｍｗ）が１００００未満のオリゴマーであり、例えばウレタン（メタ）アクリレートが挙げられる。 In addition, when an energy ray-curable compound is blended separately from the adhesive resin, a monomer or oligomer having an energy ray-polymerizable group is used as the energy ray-curable compound. The oligomer has a weight-average molecular weight (Mw) of less than 10,000, such as urethane (meth)acrylate.
　本実施形態では、エネルギー線重合性の炭素－炭素二重結合量を制御する観点から、エネルギー線硬化性を有さない粘着性樹脂１００質量部に対して、好ましくは０．１～３００質量部、より好ましくは０．５～２００質量部、さらに好ましくは１～１５０質量部である。 In the present embodiment, from the viewpoint of controlling the amount of energy ray-polymerizable carbon-carbon double bonds, it is preferably 0.1 to 300 parts by mass with respect to 100 parts by mass of the adhesive resin that does not have energy ray-curable properties. , more preferably 0.5 to 200 parts by mass, more preferably 1 to 150 parts by mass.
　以下、粘着剤層用組成物に含有されるエネルギー線硬化性の粘着性樹脂が、エネルギー線硬化性のアクリル系重合体（以下、「アクリル系重合体（Ａ）」ともいう）である場合についてより詳細に説明する。 Hereinafter, the case where the energy ray-curable adhesive resin contained in the adhesive layer composition is an energy ray-curable acrylic polymer (hereinafter also referred to as "acrylic polymer (A)"). A more detailed description will be given.
　（３．５．１　アクリル系重合体（Ａ））
　アクリル系重合体（Ａ）は、エネルギー線重合性基が導入され、かつ（メタ）アクリレート由来の構成単位を有するアクリル系重合体である。エネルギー線重合性基は、アクリル系重合体の側鎖に導入することが好ましい。 (3.5.1 Acrylic polymer (A))
The acrylic polymer (A) is an acrylic polymer into which an energy ray-polymerizable group is introduced and which has structural units derived from (meth)acrylate. The energy ray-polymerizable group is preferably introduced into the side chain of the acrylic polymer.
　アクリル系重合体（Ａ）は、アルキル（メタ）アクリレート（ａ１）由来の構成単位と、官能基含有モノマー（ａ２）由来の構成単位とを有するアクリル系共重合体（Ａ０）に、エネルギー線重合性基を有する重合性化合物（Ｘａ）を反応させた反応物であることが好ましい。 The acrylic polymer (A) is an acrylic copolymer (A0) having structural units derived from the alkyl (meth)acrylate (a1) and structural units derived from the functional group-containing monomer (a2), and is subjected to energy beam polymerization. It is preferably a reactant obtained by reacting a polymerizable compound (Xa) having a functional group.
　アルキル（メタ）アクリレート（ａ１）としては、アルキル基の炭素数が１～１８であるアルキル（メタ）アクリレートが使用される。具体的には、メチル（メタ）アクリレート、エチル（メタ）アクリレート、プロピル（メタ）アクリレート、ｎ－ブチル（メタ）アクリレート、ｎ－ペンチル（メタ）アクリレート、ｎ－ヘキシル（メタ）アクリレート、２－エチルヘキシル（メタ）アクリレート、イソオクチル（メタ）アクリレート、ｎ－デシル（メタ）アクリレート、ｎ－ドデシル（メタ）アクリレート、ｎ－トリデシル（メタ）アクリレート、ミリスチル（メタ）アクリレート、パルミチル（メタ）アクリレート、ステアリル（メタ）アクリレート等が挙げられる。 As the alkyl (meth)acrylate (a1), an alkyl (meth)acrylate having an alkyl group with 1 to 18 carbon atoms is used. Specifically, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, n-pentyl (meth) acrylate, n-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, n-decyl (meth) acrylate, n-dodecyl (meth) acrylate, n-tridecyl (meth) acrylate, myristyl (meth) acrylate, palmityl (meth) acrylate, stearyl (meth) acrylate ) acrylates and the like.
　これらの中でも、アルキル（メタ）アクリレート（ａ１）は、アルキル基の炭素数が４～８であるアルキル（メタ）アクリレートであることが好ましい。具体的には、２－エチルヘキシル（メタ）アクリレート、ｎ－ブチル（メタ）アクリレートが好ましく、ｎ－ブチル（メタ）アクリレートがより好ましい。なお、それらは、１種単独で使用してもよいし、２種以上を組み合わせて用いてもよい。 Among these, the alkyl (meth)acrylate (a1) is preferably an alkyl (meth)acrylate having an alkyl group with 4 to 8 carbon atoms. Specifically, 2-ethylhexyl (meth)acrylate and n-butyl (meth)acrylate are preferred, and n-butyl (meth)acrylate is more preferred. In addition, they may be used individually by 1 type, and may be used in combination of 2 or more type.
　アクリル系共重合体（Ａ０）における、アルキル（メタ）アクリレート（ａ１）由来の構成単位の含有量は、形成される粘着剤層の粘着力を向上させる観点から、アクリル系共重合体（Ａ０）の全構成単位（１００質量％）に対して、好ましくは４０～９８質量％、より好ましくは４５～９５質量％、さらに好ましくは５０～９０質量％である。 The content of the structural unit derived from the alkyl (meth)acrylate (a1) in the acrylic copolymer (A0) is adjusted to the acrylic copolymer (A0) from the viewpoint of improving the adhesive strength of the pressure-sensitive adhesive layer to be formed. is preferably 40 to 98% by mass, more preferably 45 to 95% by mass, and still more preferably 50 to 90% by mass, relative to the total structural units (100% by mass) of.
　例えば、アルキル（メタ）アクリレート（ａ１）は、上記の２－エチルヘキシル（メタ）アクリレートおよびｎ－ブチル（メタ）アクリレートに加えて、エチル（メタ）アクリレート、メチル（メタ）アクリレート等を含有してもよい。これらのモノマーを含有させることで、粘着剤層の粘着性能を所望のものに調整しやすくなる。 For example, the alkyl (meth)acrylate (a1) may contain ethyl (meth)acrylate, methyl (meth)acrylate, etc. in addition to the above 2-ethylhexyl (meth)acrylate and n-butyl (meth)acrylate. good. By containing these monomers, it becomes easier to adjust the adhesive performance of the adhesive layer to a desired one.
　官能基含有モノマー（ａ２）は、ヒドロキシ基、カルボキシ基、エポキシ基、アミノ基、シアノ基、窒素原子含有環基、アルコキシシリル基等の官能基を有するモノマーである。官能基含有モノマー（ａ２）としては、上記した中でも、ヒドロキシ基含有モノマー、カルボキシ基含有モノマー、及びエポキシ基含有モノマーから選ばれる１種以上が好ましい。 The functional group-containing monomer (a2) is a monomer having a functional group such as a hydroxy group, a carboxyl group, an epoxy group, an amino group, a cyano group, a nitrogen atom-containing ring group, an alkoxysilyl group, or the like. As the functional group-containing monomer (a2), among those mentioned above, one or more selected from hydroxyl group-containing monomers, carboxy group-containing monomers, and epoxy group-containing monomers are preferable.
　ヒドロキシ基含有モノマーとしては、例えば、２－ヒドロキシエチル（メタ）アクリレート、２－ヒドロキシプロピル（メタ）アクリレート、３－ヒドロキシプロピル（メタ）アクリレート、２－ヒドロキシブチル（メタ）アクリレート、３－ヒドロキシブチル（メタ）アクリレート、４－ヒドロキシブチル（メタ）アクリレート等のヒドロキシアルキル（メタ）アクリレート；ビニルアルコール、アリルアルコール等の不飽和アルコール等が挙げられる。 Examples of hydroxy group-containing monomers include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 3-hydroxybutyl ( hydroxyalkyl (meth)acrylates such as meth)acrylate and 4-hydroxybutyl (meth)acrylate; and unsaturated alcohols such as vinyl alcohol and allyl alcohol.
　カルボキシ基含有モノマーとしては、（メタ）アクリル酸、マレイン酸、フマル酸、イタコン酸等が挙げられる。 Carboxy group-containing monomers include (meth)acrylic acid, maleic acid, fumaric acid, and itaconic acid.
　エポキシ含有モノマーとしては、エポキシ基含有（メタ）アクリル酸エステル及び非アクリル系エポキシ基含有モノマーが挙げられる。エポキシ基含有（メタ）アクリル酸エステルとしては、例えば、グリシジル（メタ）アクリレート、β－メチルグリシジル（メタ）アクリレート、（３，４－エポキシシクロヘキシル）メチル（メタ）アクリレート、３－エポキシシクロ－２－ヒドロキシプロピル（メタ）アクリレート等が挙げられる。また、非アクリル系エポキシ基含有モノマーとしては、例えば、グリシジルクロトネート、アリルグリシジルエーテル等が挙げられる。 Epoxy-containing monomers include epoxy group-containing (meth)acrylic acid esters and non-acrylic epoxy group-containing monomers. Examples of epoxy group-containing (meth)acrylic esters include glycidyl (meth)acrylate, β-methylglycidyl (meth)acrylate, (3,4-epoxycyclohexyl)methyl (meth)acrylate, 3-epoxycyclo-2- Hydroxypropyl (meth)acrylate and the like. Examples of non-acrylic epoxy group-containing monomers include glycidyl crotonate and allyl glycidyl ether.
　官能基含有モノマー（ａ２）は、１種単独で使用してもよいし、２種以上を組み合わせて用いてもよい。 The functional group-containing monomer (a2) may be used alone or in combination of two or more.
　官能基含有モノマー（ａ２）としては、上記した中でも、ヒドロキシ基含有モノマーがより好ましく、中でも、ヒドロキシアルキル（メタ）アクリレートがより好ましく、２－ヒドロキシエチル（メタ）アクリレートがさらに好ましい。 Among the above-mentioned functional group-containing monomers (a2), hydroxy group-containing monomers are more preferable, hydroxyalkyl (meth)acrylates are more preferable, and 2-hydroxyethyl (meth)acrylate is even more preferable.
　（ａ２）成分として、ヒドロキシアルキル（メタ）アクリレートを使用することで、比較的容易にアクリル系共重合体（Ａ０）に、重合性化合物（Ｘａ）を反応させることが可能になる。 By using a hydroxyalkyl (meth)acrylate as the component (a2), it becomes possible to relatively easily react the acrylic copolymer (A0) with the polymerizable compound (Xa).
　アクリル系共重合体（Ａ０）における、官能基含有モノマー（ａ２）由来の構成単位の含有量は、アクリル系共重合体（Ａ０）の全構成単位（１００質量％）に対して、好ましくは１～３５質量％、より好ましくは３～３２質量％、さらに好ましくは６～３０質量％である。 The content of structural units derived from the functional group-containing monomer (a2) in the acrylic copolymer (A0) is preferably 1 based on the total structural units (100% by mass) of the acrylic copolymer (A0). ~35% by mass, more preferably 3 to 32% by mass, still more preferably 6 to 30% by mass.
　含有量が１質量％以上であれば、重合性化合物（Ｘａ）との反応点となる官能基を一定量確保できる。そのため、エネルギー線の照射により粘着剤層を適切に硬化できるので、エネルギー線照射後の粘着力を低くすることが可能になる。また、含有量が３０質量％以下であれば、粘着剤層用組成物の溶液を塗布し、粘着剤層を形成する際、十分なポットライフを確保することができる。 If the content is 1% by mass or more, a certain amount of functional groups that serve as reaction points with the polymerizable compound (Xa) can be secured. Therefore, the pressure-sensitive adhesive layer can be appropriately cured by irradiation with energy rays, so that the adhesive strength after irradiation with energy rays can be reduced. Moreover, if the content is 30% by mass or less, sufficient pot life can be ensured when the solution of the adhesive layer composition is applied to form the adhesive layer.
　アクリル系共重合体（Ａ０）は、アルキル（メタ）アクリレート（ａ１）と官能基含有モノマー（ａ２）の共重合体であってもよいが、（ａ１）成分と、（ａ２）成分と、これら（ａ１）及び（ａ２）成分以外のその他のモノマー（ａ３）との共重合体であってもよい。 The acrylic copolymer (A0) may be a copolymer of an alkyl (meth)acrylate (a1) and a functional group-containing monomer (a2). It may be a copolymer with a monomer (a3) other than the components (a1) and (a2).
　その他のモノマー（ａ３）としては、例えば、シクロヘキシル（メタ）アクリレート、ベンジル（メタ）アクリレート、イソボルニル（メタ）アクリレート、ジシクロペンタニル（メタ）アクリレート、ジシクロペンテニル（メタ）アクリレート、ジシクロペンテニルオキシエチル（メタ）アクリレート等の環状構造を有する（メタ）アクリレート、酢酸ビニル、スチレン等が挙げられる。その他のモノマー（ａ３）は、１種単独で使用してもよいし、２種以上を組み合わせて用いてもよい。 Other monomers (a3) include, for example, cyclohexyl (meth)acrylate, benzyl (meth)acrylate, isobornyl (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyloxy Examples include (meth)acrylates having a cyclic structure such as ethyl (meth)acrylate, vinyl acetate, styrene, and the like. Other monomers (a3) may be used singly or in combination of two or more.
　アクリル系共重合体（Ａ０）における、その他のモノマー（ａ３）由来の構成単位の含有量は、アクリル系共重合体（Ａ０）の全構成単位（１００質量％）に対して、好ましくは０～３０質量％、より好ましくは０～１０質量％、さらに好ましくは０～５質量％である。 The content of structural units derived from the other monomer (a3) in the acrylic copolymer (A0) is preferably 0 to 30% by mass, more preferably 0 to 10% by mass, and even more preferably 0 to 5% by mass.
　重合性化合物（Ｘａ）は、エネルギー線重合性基と、アクリル系共重合体（Ａ０）の（ａ２）成分由来の構成単位中の官能基と反応し得る置換基（以下、単に「反応性置換基」ともいう）とを有する化合物である。 The polymerizable compound (Xa) includes an energy ray-polymerizable group and a substituent capable of reacting with a functional group in the structural unit derived from the (a2) component of the acrylic copolymer (A0) (hereinafter simply referred to as "reactive substitution (also referred to as "group").
　エネルギー線重合性基は、エネルギー線重合性の炭素－炭素二重結合を含む基であればよい。たとえば、（メタ）アクリロイル基、ビニル基等が挙げられ、（メタ）アクリロイル基が好ましい。また、重合性化合物（Ｘａ）は、エネルギー線重合性基を１分子あたり１～５個有する化合物であることが好ましい。 The energy ray-polymerizable group may be any group containing an energy ray-polymerizable carbon-carbon double bond. For example, a (meth)acryloyl group, a vinyl group and the like can be mentioned, and a (meth)acryloyl group is preferred. Moreover, the polymerizable compound (Xa) is preferably a compound having 1 to 5 energy ray-polymerizable groups per molecule.
　重合性化合物（Ｘａ）における反応性置換基としては、官能基含有モノマー（ａ２）が有する官能基に応じて適宜変更すればよいが、例えば、イソシアネート基、カルボキシル基、エポキシ基等が挙げられ、反応性等の観点から、イソシアネート基が好ましい。重合性化合物（Ｘａ）は、イソシアネート基を有すると、例えば、官能基含有モノマー（ａ２）の官能基がヒドロキシ基である場合に、アクリル系共重合体（Ａ０）に容易に反応することが可能になる。 The reactive substituent in the polymerizable compound (Xa) may be appropriately changed according to the functional group of the functional group-containing monomer (a2). From the viewpoint of reactivity and the like, an isocyanate group is preferred. When the polymerizable compound (Xa) has an isocyanate group, for example, when the functional group of the functional group-containing monomer (a2) is a hydroxy group, it can easily react with the acrylic copolymer (A0). become.
　具体的な重合性化合物（Ｘａ）としては、例えば、（メタ）アクリロイルオキシエチルイソシアネート、メタ－イソプロペニル－α，α－ジメチルベンジルイソシアネート、（メタ）アクリロイルイソシアネート、アリルイソシアネート、グリシジル（メタ）アクリレート、（メタ）アクリル酸等が挙げられる。これらの重合性化合物（Ｘａ）は、単独で又は２種以上を組み合わせて用いてもよい。 Specific polymerizable compounds (Xa) include, for example, (meth)acryloyloxyethyl isocyanate, meta-isopropenyl-α,α-dimethylbenzyl isocyanate, (meth)acryloyl isocyanate, allyl isocyanate, glycidyl (meth)acrylate, (Meth) acrylic acid and the like. These polymerizable compounds (Xa) may be used alone or in combination of two or more.
　これらの中でも、上記反応性置換基として好適なイソシアネート基を有しており、且つ主鎖とエネルギー線重合性基との距離が適当となる化合物であるとの観点から、（メタ）アクリロイルオキシエチルイソシアネートが好ましい。 Among these, (meth)acryloyloxyethyl Isocyanates are preferred.
　エネルギー線重合性の炭素－炭素二重結合量を制御する観点から、重合性化合物（Ｘａ）は、アクリル系共重合体（Ａ０）における官能基含有モノマー（ａ２）由来の官能基全量（１００当量）のうち、好ましくは５０～９８当量、より好ましくは５５～９３当量が官能基に反応される。 From the viewpoint of controlling the amount of energy ray polymerizable carbon-carbon double bonds, the polymerizable compound (Xa) is added to the total amount of functional groups derived from the functional group-containing monomer (a2) in the acrylic copolymer (A0) (100 equivalents ), preferably 50 to 98 equivalents, more preferably 55 to 93 equivalents are reacted with the functional group.
　アクリル系重合体（Ａ）の重量平均分子量（Ｍｗ）は、好ましくは３０万～１６０万、より好ましくは４０万～１４０万である。このようなＭｗを有することで、粘着剤層に適切な粘着性を付与することが可能になる。 The weight average molecular weight (Mw) of the acrylic polymer (A) is preferably 300,000 to 1,600,000, more preferably 400,000 to 1,400,000. By having such Mw, it becomes possible to impart appropriate adhesiveness to the adhesive layer.
　粘着性樹脂がエネルギー線硬化性を有する場合であっても、粘着剤層用組成物には、粘着性樹脂以外のエネルギー線硬化性化合物が含まれることが好ましい。このようなエネルギー線硬化性化合物としては、分子内に不飽和基を有し、エネルギー線照射により重合硬化可能なモノマー又はオリゴマーが好ましい。 Even if the adhesive resin has energy ray-curable properties, the composition for the adhesive layer preferably contains an energy ray-curable compound other than the adhesive resin. As such an energy ray-curable compound, a monomer or oligomer having an unsaturated group in the molecule and capable of being polymerized and cured by energy ray irradiation is preferable.
　具体的には、例えば、トリメチロールプロパントリ（メタ）アクリレート、ペンタエリスリトール（メタ）アクリレート、ペンタエリスリトールテトラ（メタ）アクリレート、ジペンタエリスリトールヘキサ（メタ）アクリレート、１，４－ブチレングリコールジ（メタ）アクリレート、１，６－へキサンジオール（メタ）アクリレート等の多価（メタ）アクリレートモノマー、ウレタン（メタ）アクリレート、ポリエステル（メタ）アクリレート，ポリエーテル（メタ）アクリレート、エポキシ（メタ）アクリレート等のオリゴマーが挙げられる。 Specifically, for example, trimethylolpropane tri(meth)acrylate, pentaerythritol (meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, 1,4-butylene glycol di(meth) Polyvalent (meth)acrylate monomers such as acrylates and 1,6-hexanediol (meth)acrylates, oligomers such as urethane (meth)acrylates, polyester (meth)acrylates, polyether (meth)acrylates, and epoxy (meth)acrylates is mentioned.
　これらの中でも、比較的分子量が高く、粘着剤層の表面抵抗率を上述した範囲内とする観点から、ウレタン（メタ）アクリレートオリゴマーが好ましい。 Among these, urethane (meth)acrylate oligomers are preferable from the viewpoint of having a relatively high molecular weight and keeping the surface resistivity of the pressure-sensitive adhesive layer within the range described above.
　エネルギー線重合性の炭素－炭素二重結合量を制御する観点から、エネルギー線硬化性化合物の含有量は、アクリル系重合体（Ａ）１００質量部に対して、好ましくは０．１～３００質量部、より好ましくは０．５～２００質量部、さらに好ましくは１～１５０質量部である。 From the viewpoint of controlling the energy ray-polymerizable carbon-carbon double bond content, the content of the energy ray-curable compound is preferably 0.1 to 300 mass parts with respect to 100 mass parts of the acrylic polymer (A). parts, more preferably 0.5 to 200 parts by mass, and still more preferably 1 to 150 parts by mass.
　（３．５．２　架橋剤）
　粘着剤層用組成物は、さらに架橋剤を含有することが好ましい。粘着剤層用組成物は、例えば塗布後に加熱されることで、架橋剤によって架橋される。粘着剤層は、アクリル系重合体（Ａ）が架橋剤によって架橋されることで、塗膜が適切に形成され、粘着剤層としての機能を発揮しやすくなる。 (3.5.2 Cross-linking agent)
The adhesive layer composition preferably further contains a cross-linking agent. The pressure-sensitive adhesive layer composition is crosslinked by a crosslinking agent, for example, by being heated after application. By cross-linking the acrylic polymer (A) with a cross-linking agent, the pressure-sensitive adhesive layer is appropriately formed as a coating film and easily exhibits its function as a pressure-sensitive adhesive layer.
　架橋剤としては、イソシアネート系架橋剤、エポキシ系架橋剤、アジリジン系架橋剤、キレート系架橋剤が挙げられ、これらの中では、イソシアネート系架橋剤が好ましい。架橋剤は、単独で又は２種以上を組み合わせて用いてもよい。 Examples of cross-linking agents include isocyanate-based cross-linking agents, epoxy-based cross-linking agents, aziridine-based cross-linking agents, and chelate-based cross-linking agents. Among these, isocyanate-based cross-linking agents are preferred. You may use a crosslinking agent individually or in combination of 2 or more types.
　イソシアネート系架橋剤としては、ポリイソシアネート化合物が挙げられる。ポリイソシアネート化合物の具体例としては、トリレンジイソシアネート、ジフェニルメタンジイソシアネート、キシリレンジイソシアネート等の芳香族ポリイソシアネート、ヘキサメチレンジイソシアネート等の脂肪族ポリイソシアネート、イソホロンジイソシアネート、水素添加ジフェニルメタンジイソシアネート等の脂環族ポリイソシアネートなどが挙げられる。また、これらのビウレット体、イソシアヌレート体、さらにはエチレングリコール、プロピレングリコール、ネオペンチルグリコール、トリメチロールプロパン、ヒマシ油等の低分子活性水素含有化合物との反応物であるアダクト体等も挙げられる。 Examples of isocyanate-based cross-linking agents include polyisocyanate compounds. Specific examples of polyisocyanate compounds include aromatic polyisocyanates such as tolylene diisocyanate, diphenylmethane diisocyanate and xylylene diisocyanate; aliphatic polyisocyanates such as hexamethylene diisocyanate; and alicyclic polyisocyanates such as isophorone diisocyanate and hydrogenated diphenylmethane diisocyanate. etc. Also included are biuret and isocyanurate forms thereof, as well as adduct forms which are reactants with low-molecular-weight active hydrogen-containing compounds such as ethylene glycol, propylene glycol, neopentyl glycol, trimethylolpropane and castor oil.
　上記した中では、トリレンジイソシアネート等の芳香族ポリイソシアネートの多価アルコール（例えば、トリメチロールプロパン等）アダクト体が好ましい。 Among the above, polyhydric alcohol (for example, trimethylolpropane, etc.) adducts of aromatic polyisocyanates such as tolylene diisocyanate are preferable.
　架橋剤の含有量は、アクリル系重合体（Ａ）１００質量部に対して、好ましくは０．０１～１０質量部、より好ましくは０．０３～７質量部である。 The content of the cross-linking agent is preferably 0.01 to 10 parts by mass, more preferably 0.03 to 7 parts by mass, based on 100 parts by mass of the acrylic polymer (A).
　（３．５．３　光重合開始剤）
　粘着剤層用組成物は、さらに光重合開始剤を含有することが好ましい。粘着剤層用組成物が、光重合開始剤を含有することで、粘着剤層用組成物の紫外線等によるエネルギー線硬化を進行させやすくなる。 (3.5.3 Photoinitiator)
The adhesive layer composition preferably further contains a photopolymerization initiator. When the composition for the pressure-sensitive adhesive layer contains a photopolymerization initiator, it becomes easier to proceed the energy ray curing of the composition for the pressure-sensitive adhesive layer by ultraviolet light or the like.
　光重合開始剤としては、例えば、アセトフェノン、２，２－ジエトキシベンゾフェノン、４－メチルベンゾフェノン、２，４，６－トリメチルベンゾフェノン、ミヒラーケトン、ベンゾイン、ベンゾインメチルエーテル、ベンゾインエチルエーテル、ベンゾインイソプロピルエーテル、ベンゾインイソブチルエーテル、ベンジルジフェニサルファイド、テトラメチルチウラムモノサルファイド、ベンジルジメチルケタール、ジベンジル、ジアセチル、１－クロルアントラキノン、２－クロルアントラキノン、２－エチルアントラキノン、２，２－ジメトキシ－１，２－ジフェニルエタン－１－オン、１－ヒドロキシシクロヘキシルフェニルケトン、２－メチル－１－［４－（メチルチオ）フェニル］－２－モルホリノプロパノン－１，２－ベンジル－２－ジメチルアミノ－１－（４－モルホリノフェニル）－ブタノン－１，２－ヒドロキシ－２－メチル－１－フェニル－プロパン－１－オン、ジエチルチオキサントン、イソプロピルチオキサントン、２，４，６－トリメチルベンゾイルジフェニル－フォスフィンオキサイド等の低分子量重合開始剤、オリゴ｛２－ヒドロキシ－２－メチル－１－［４－（１－メチルビニル）フェニル］プロパノン｝等のオリゴマー化された重合開始剤などが挙げられる。 Examples of photopolymerization initiators include acetophenone, 2,2-diethoxybenzophenone, 4-methylbenzophenone, 2,4,6-trimethylbenzophenone, Michler's ketone, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzyldiphenisulfide, tetramethylthiuram monosulfide, benzyldimethylketal, dibenzyl, diacetyl, 1-chloroanthraquinone, 2-chloroanthraquinone, 2-ethylanthraquinone, 2,2-dimethoxy-1,2-diphenylethane- 1-one, 1-hydroxycyclohexylphenyl ketone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropanone-1,2-benzyl-2-dimethylamino-1-(4-morpholinophenyl )-butanone-1,2-hydroxy-2-methyl-1-phenyl-propan-1-one, diethylthioxanthone, isopropylthioxanthone, 2,4,6-trimethylbenzoyldiphenyl-phosphine oxide and other low molecular weight polymerization initiators , oligomerized polymerization initiators such as oligo{2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propanone}.
　なお、光重合開始剤は、単独で又は２種以上を組み合わせて用いてもよい。また、上記した中では、２，２－ジメトキシ－１，２－ジフェニルエタン－１－オン、１－ヒドロキシシクロヘキシルフェニルケトンが好ましい。 The photopolymerization initiator may be used alone or in combination of two or more. Among the above, 2,2-dimethoxy-1,2-diphenylethan-1-one and 1-hydroxycyclohexylphenyl ketone are preferred.
　光重合開始剤の含有量は、アクリル系重合体（Ａ）１００質量部に対して、好ましくは０．０１～１０質量部、より好ましくは０．０３～７質量部、さらに好ましくは０．０５～５質量部である。 The content of the photopolymerization initiator is preferably 0.01 to 10 parts by mass, more preferably 0.03 to 7 parts by mass, and still more preferably 0.05 parts by mass with respect to 100 parts by mass of the acrylic polymer (A). ~5 parts by mass.
　粘着剤層用組成物は、本発明の効果を損なわない範囲において、他の添加剤を含有してもよい。他の添加剤としては、例えば、粘着付与剤、酸化防止剤、軟化剤（可塑剤）、充填剤、防錆剤、顔料、染料等が挙げられる。これらの添加剤を含有する場合、それぞれの添加剤の含有量は、アクリル系重合体（Ａ）１００質量部に対して、好ましくは０．０１～６質量部、より好ましくは０．０２～２質量部である。 The composition for the pressure-sensitive adhesive layer may contain other additives as long as they do not impair the effects of the present invention. Other additives include, for example, tackifiers, antioxidants, softeners (plasticizers), fillers, rust inhibitors, pigments, dyes, and the like. When these additives are contained, the content of each additive is preferably 0.01 to 6 parts by mass, more preferably 0.02 to 2 parts by mass, relative to 100 parts by mass of the acrylic polymer (A). part by mass.
　なお、粘着剤層の表面抵抗率および粘着力は、例えば、アクリル系重合体（Ａ）を構成するモノマーの種類及び量、アクリル系重合体（Ａ）に導入されるエネルギー線重合性基の量等により調整可能である。上記では、アクリル系重合体（Ａ）に導入されるエネルギー線重合性基の量等の好ましい範囲について記載し、例えば、エネルギー線重合性基の量を増やすと、硬化後の粘着力は低くなり、表面抵抗率は高くなる傾向にある。しかしながら、粘着剤層の表面抵抗率および粘着力は、上記の要因以外の要因によっても調整可能である。たとえば、、粘着剤層に配合される架橋剤の量、光重合開始剤の量等によっても適宜調整可能である。 The surface resistivity and adhesive strength of the pressure-sensitive adhesive layer are determined, for example, by the type and amount of monomers constituting the acrylic polymer (A), and the amount of energy ray-polymerizable groups introduced into the acrylic polymer (A). etc. can be adjusted. The above describes the preferred range of the amount of the energy ray-polymerizable group to be introduced into the acrylic polymer (A). , the surface resistivity tends to be high. However, the surface resistivity and adhesive strength of the adhesive layer can be adjusted by factors other than those mentioned above. For example, it can be appropriately adjusted by adjusting the amount of the cross-linking agent and the amount of the photopolymerization initiator mixed in the pressure-sensitive adhesive layer.
　（４．帯電防止層）
　帯電防止層は、基材と粘着剤層との間に配置されている。帯電防止層では、帯電防止成分が、半導体加工用保護シートが貼付されたウエハの加工等に起因する帯電を漏洩することにより、帯電圧が高くなることを抑制することができる。帯電防止層の組成は、粘着剤層をウエハ等から剥離する際の剥離帯電圧を所定の値以下にできる程度の帯電防止性を有していればよい。本実施形態では、剥離帯電圧は５００Ｖ以下にすることが好ましい。 (4. Antistatic layer)
The antistatic layer is arranged between the substrate and the adhesive layer. In the antistatic layer, the antistatic component can suppress an increase in static voltage due to leakage of static charge resulting from processing of the wafer to which the protective sheet for semiconductor processing is adhered. The composition of the antistatic layer may have such an antistatic property that the peeling electrostatic voltage when peeling the pressure-sensitive adhesive layer from a wafer or the like can be reduced to a predetermined value or less. In this embodiment, it is preferable that the peeling electrification voltage is 500 V or less.
　帯電防止層の厚さは、１０ｎｍ以上であることが好ましく、１５ｎｍ以上であることがより好ましく、２０ｎｍ以上であることがさらに好ましく、６０ｎｍ以上であることが特に好ましい。また、当該厚さは、３００ｎｍ以下であることが好ましく、２５０ｎｍ以下であることがより好ましく、２００ｎｍ以下であることがさらに好ましい。 The thickness of the antistatic layer is preferably 10 nm or more, more preferably 15 nm or more, even more preferably 20 nm or more, and particularly preferably 60 nm or more. Also, the thickness is preferably 300 nm or less, more preferably 250 nm or less, and even more preferably 200 nm or less.
　（４．１　帯電防止層用組成物）
　本実施形態では、帯電防止層は、高分子化合物を含む組成物（帯電防止層用組成物）から構成されることが好ましい。このような組成物としては、帯電防止成分としての導電性高分子化合物を含む組成物、帯電防止成分と高分子化合物とを含む組成物等が例示される。帯電防止層用組成物は、導電性高分子化合物を含む組成物であることが好ましい。 (4.1 Composition for antistatic layer)
In this embodiment, the antistatic layer is preferably composed of a composition containing a polymer compound (composition for antistatic layer). Examples of such a composition include a composition containing a conductive polymer compound as an antistatic component, a composition containing an antistatic component and a polymer compound, and the like. The antistatic layer composition is preferably a composition containing a conductive polymer compound.
　導電性高分子化合物としては、たとえば、ポリチオフェン系ポリマー、ポリピロール系ポリマー、ポリアニリン系ポリマーが挙げられる。本実施形態では、ポリチオフェン系ポリマーが好ましい。 Examples of conductive polymer compounds include polythiophene-based polymers, polypyrrole-based polymers, and polyaniline-based polymers. In this embodiment, a polythiophene-based polymer is preferred.
　ポリチオフェン系ポリマーとしては、たとえば、ポリチオフェン、ポリ(３－アルキルチオフェン)、ポリ(３－チオフェン－β－エタンスルホン酸)、ポリアルキレンジオキシチオフェンとポリスチレンスルホネート（ＰＳＳ）との混合物（ドープされたものを含む）等が挙げられる。これらの中でも、ポリアルキレンジオキシチオフェンとポリスチレンスルホネートとの混合物が好ましい。上記ポリアルキレンジオキシチオフェンとしては、ポリ（３，４－エチレンジオキシチオフェン）（ＰＥＤＯＴ）、ポリプロピレンジオキシチオフェン、ポリ（エチレン／プロピレン）ジオキシチオフェン等が挙げられ、中でもポリ（３，４－エチレンジオキシチオフェン）が好ましい。すなわち、上記の中でも、ポリ（３，４－エチレンジオキシチオフェン）とポリスチレンスルホネートとの混合物（ＰＳＳをドープしたＰＥＤＯＴ）が特に好ましい。 Polythiophene-based polymers include, for example, polythiophene, poly(3-alkylthiophene), poly(3-thiophene-β-ethanesulfonic acid), mixtures of polyalkylenedioxythiophenes and polystyrene sulfonate (PSS) (doped including) and the like. Among these, a mixture of polyalkylenedioxythiophene and polystyrene sulfonate is preferred. Examples of the polyalkylenedioxythiophene include poly(3,4-ethylenedioxythiophene) (PEDOT), polypropylenedioxythiophene, poly(ethylene/propylene)dioxythiophene, etc. Among them, poly(3,4- ethylenedioxythiophene) is preferred. That is, among the above, a mixture of poly(3,4-ethylenedioxythiophene) and polystyrene sulfonate (PSS-doped PEDOT) is particularly preferred.
　ポリピロール系ポリマーとしては、たとえば、ポリピロール、ポリ３－メチルピロール、ポリ３－オクチルピロール等が挙げられる。 Examples of polypyrrole-based polymers include polypyrrole, poly-3-methylpyrrole, and poly-3-octylpyrrole.
　ポリアニリン系ポリマーとしては、たとえば、ポリアニリン、ポリメチルアニリン、ポリメトキシアニリン等が挙げられる。 Examples of polyaniline-based polymers include polyaniline, polymethylaniline, and polymethoxyaniline.
　帯電防止成分と高分子化合物とを含む組成物としては、帯電防止成分とバインダー樹脂とを含む組成物が挙げられる。帯電防止成分としては、上記の導電性高分子化合物、界面活性剤、イオン液体、導電性無機化合物等が例示される。 A composition containing an antistatic component and a polymer compound includes a composition containing an antistatic component and a binder resin. Examples of the antistatic component include the above conductive polymer compounds, surfactants, ionic liquids, conductive inorganic compounds, and the like.
　界面活性剤としては、カチオン性界面活性剤、アニオン性界面活性剤、両性界面活性剤、非イオン性界面活性剤から選ばれる少なくとも１つであればよい。たとえば、４級アンモニウム塩を含むカチオン性界面活性剤が例示される。導電性無機化合物としては、各種金属、導電性酸化物等が例示される。 The surfactant may be at least one selected from cationic surfactants, anionic surfactants, amphoteric surfactants, and nonionic surfactants. Examples include cationic surfactants containing quaternary ammonium salts. Examples of conductive inorganic compounds include various metals and conductive oxides.
　また、バインダー樹脂は特に制限されない。たとえば、ポリエステル樹脂、アクリル樹脂、ポリビニル樹脂、ウレタン樹脂、メラミン樹脂、エポキシ樹脂等が挙げられる。また、架橋剤を併用してもよい。架橋剤としては、たとえば、メチロール化あるいはアルキロール化したメラミン系化合物、尿素系化合物、グリオキザール系化合物、アクリルアミド系化合物、エポキシ系化合物、イソシアネート系化合物等が挙げられる。 Also, the binder resin is not particularly limited. Examples thereof include polyester resins, acrylic resins, polyvinyl resins, urethane resins, melamine resins, and epoxy resins. Moreover, you may use a crosslinking agent together. Examples of cross-linking agents include methylolated or alkylolated melamine compounds, urea compounds, glyoxal compounds, acrylamide compounds, epoxy compounds, isocyanate compounds, and the like.
　帯電防止層用組成物中の帯電防止剤の含有量は、所望の帯電防止性能に応じて適宜決定すればよい。具体的には、帯電防止層用組成物中における帯電防止剤の含有量は、０．１～２０質量％であることが好ましい。 The content of the antistatic agent in the antistatic layer composition may be appropriately determined according to the desired antistatic performance. Specifically, the content of the antistatic agent in the antistatic layer composition is preferably 0.1 to 20% by mass.
　（５．緩衝層）
　緩衝層は、図１Ａに示すように、粘着剤層が形成されている基材の主面と反対側の主面上に形成されている。緩衝層４０は、基材と比較して軟質の層であり、ウエハの裏面研削時の応力を緩和して、ウエハに割れ及び欠けが生じることを防止する。また、半導体加工用保護シートを貼付したウエハは、裏面研削時に、半導体加工用保護シートを介して真空テーブル上に配置されるが、半導体加工用保護シートの構成層として緩衝層を有することで、真空テーブルに適切に保持されやすくなる。 (5. Buffer layer)
The buffer layer, as shown in FIG. 1A, is formed on the main surface of the base material opposite to the main surface on which the pressure-sensitive adhesive layer is formed. The buffer layer 40 is a softer layer than the base material, and relieves the stress during back-grinding of the wafer to prevent cracking and chipping of the wafer. In addition, the wafer to which the protective sheet for semiconductor processing is attached is placed on the vacuum table through the protective sheet for semiconductor processing during back grinding. It is easier to hold properly on the vacuum table.
　このような緩衝層は、ＤＢＧ、特にＬＤＢＧによりウエハを加工する場合に有用である。 Such a buffer layer is useful when processing wafers by DBG, especially LDBG.
　緩衝層の厚さは、５～１００μｍであることが好ましく、１～１００μｍであることがより好ましく、５～８０μｍであることがさらに好ましい。緩衝層の厚さを上記範囲とすることで、緩衝層が裏面研削時の応力を適切に緩和できるようになる。 The thickness of the buffer layer is preferably 5-100 μm, more preferably 1-100 μm, and even more preferably 5-80 μm. By setting the thickness of the buffer layer within the above range, the buffer layer can appropriately relax the stress during back grinding.
　緩衝層は、エネルギー線重合性化合物を含む緩衝層用組成物から形成される層であってもよいし、ポリプロピレンフィルム、エチレン－酢酸ビニル共重合体フィルム、アイオノマー樹脂フィルム、エチレン・（メタ）アクリル酸共重合体フィルム、エチレン・（メタ）アクリル酸エステル共重合体フィルム、ＬＤＰＥフィルム、ＬＬＤＰＥフィルム等のフィルムであってもよい。 The buffer layer may be a layer formed from a buffer layer composition containing an energy ray-polymerizable compound, a polypropylene film, an ethylene-vinyl acetate copolymer film, an ionomer resin film, an ethylene/(meth)acrylic film. Films such as acid copolymer films, ethylene/(meth)acrylate copolymer films, LDPE films, and LLDPE films may be used.
　（５．１　緩衝層用組成物）
　エネルギー線重合性化合物を含む緩衝層用組成物は、エネルギー線が照射されることで硬化することが可能になる。 (5.1 Composition for buffer layer)
A buffer layer composition containing an energy ray-polymerizable compound can be cured by being irradiated with an energy ray.
　また、エネルギー線重合性化合物を含む緩衝層用組成物は、より具体的には、ウレタン（メタ）アクリレート（ｂ１）と環形成原子数６～２０の脂環基又は複素環基を有する重合性化合物（ｂ２）とを含むことが好ましい。また、緩衝層用組成物は、上記（ｂ１）及び（ｂ２）成分に加えて、官能基を有する重合性化合物（ｂ３）を含有してもよい。また、緩衝層用組成物は、上記の成分に加えて、光重合開始剤を含有してもよい。さらに、緩衝層用組成物は、本発明の効果を損なわない範囲において、その他の添加剤や樹脂成分を含有してもよい。 Further, the buffer layer composition containing the energy ray-polymerizable compound is more specifically polymerizable having a urethane (meth)acrylate (b1) and an alicyclic or heterocyclic group having 6 to 20 ring-forming atoms. It preferably contains the compound (b2). In addition to the components (b1) and (b2), the buffer layer composition may contain a polymerizable compound (b3) having a functional group. The buffer layer composition may also contain a photopolymerization initiator in addition to the above components. Furthermore, the buffer layer composition may contain other additives and resin components within the range that does not impair the effects of the present invention.
　以下、エネルギー線重合性化合物を含む緩衝層用組成物中に含まれる各成分について詳細に説明する。 Each component contained in the buffer layer composition containing the energy ray-polymerizable compound will be described in detail below.
　（５．１．１　ウレタン（メタ）アクリレート（ｂ１））
　ウレタン（メタ）アクリレート（ｂ１）とは、少なくとも（メタ）アクリロイル基及びウレタン結合を有する化合物であり、エネルギー線照射により重合硬化する性質を有するものである。ウレタン（メタ）アクリレート（ｂ１）は、オリゴマーまたはポリマーである。 (5.1.1 Urethane (meth)acrylate (b1))
The urethane (meth)acrylate (b1) is a compound having at least a (meth)acryloyl group and a urethane bond, and has the property of being polymerized and cured by energy ray irradiation. Urethane (meth)acrylates (b1) are oligomers or polymers.
　成分（ｂ１）の重量平均分子量（Ｍｗ）は、好ましくは１，０００～１００，０００、より好ましくは２，０００～６０，０００、さらに好ましくは３，０００～２０，０００である。また、成分（ｂ１）中の（メタ）アクリロイル基数（以下、「官能基数」ともいう）としては、単官能、２官能、もしくは３官能以上でもよいが、単官能又は２官能であることが好ましい。 The weight average molecular weight (Mw) of component (b1) is preferably 1,000 to 100,000, more preferably 2,000 to 60,000, still more preferably 3,000 to 20,000. In addition, the number of (meth)acryloyl groups (hereinafter also referred to as "number of functional groups") in component (b1) may be monofunctional, difunctional, or trifunctional or more, but is preferably monofunctional or difunctional. .
　成分（ｂ１）は、例えば、ポリオール化合物と、多価イソシアネート化合物とを反応させて得られる末端イソシアネートウレタンプレポリマーに、ヒドロキシル基を有する（メタ）アクリレートを反応させて得ることができる。なお、成分（ｂ１）は、単独で又は２種以上を組み合わせて用いてもよい。 Component (b1) can be obtained, for example, by reacting a terminal isocyanate urethane prepolymer obtained by reacting a polyol compound and a polyvalent isocyanate compound with a (meth)acrylate having a hydroxyl group. In addition, you may use a component (b1) individually or in combination of 2 or more types.
　成分（ｂ１）の原料となるポリオール化合物は、ヒドロキシ基を２つ以上有する化合物であれば特に限定されない。２官能のジオール、３官能のトリオール、４官能以上のポリオールのいずれであってもよいが、２官能のジオールが好ましく、ポリエステル型ジオールまたはポリカーボネート型ジオールがより好ましい。 The polyol compound used as the raw material for component (b1) is not particularly limited as long as it is a compound having two or more hydroxy groups. Any of difunctional diols, trifunctional triols, and tetrafunctional or higher polyols may be used, but bifunctional diols are preferred, and polyester type diols or polycarbonate type diols are more preferred.
　多価イソシアネート化合物としては、例えば、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、トリメチルヘキサメチレンジイソシアネート等の脂肪族系ポリイソシアネート類；イソホロンジイソシアネート、ノルボルナンジイソシアネート、ジシクロヘキシルメタン－４，４’－ジイソシアネート、ジシクロヘキシルメタン－２，４’－ジイソシアネート、ω，ω’－ジイソシアネートジメチルシクロヘキサン等の脂環族系ジイソシアネート類；４，４’－ジフェニルメタンジイソシアネート、トリレンジイソシアネート、キシリレンジイソシアネート、トリジンジイソシアネート、テトラメチレンキシリレンジイソシアネート、ナフタレン－１，５－ジイソシアネート等の芳香族系ジイソシアネート類等が挙げられる。 Examples of polyvalent isocyanate compounds include aliphatic polyisocyanates such as tetramethylene diisocyanate, hexamethylene diisocyanate and trimethylhexamethylene diisocyanate; Alicyclic diisocyanates such as ,4'-diisocyanate, ω,ω'-diisocyanatedimethylcyclohexane; 4,4'-diphenylmethane diisocyanate, tolylene diisocyanate, xylylene diisocyanate, tolidine diisocyanate, tetramethylene xylylene diisocyanate, naphthalene- aromatic diisocyanates such as 1,5-diisocyanate;
　これらの中でも、イソホロンジイソシアネート、ヘキサメチレンジイソシアネート、キシリレンジイソシアネートが好ましい。 Among these, isophorone diisocyanate, hexamethylene diisocyanate, and xylylene diisocyanate are preferred.
　上述のポリオール化合物と、多価イソシアネート化合物とを反応させて得られる末端イソシアネートウレタンプレポリマーに、ヒドロキシ基を有する（メタ）アクリレートを反応させてウレタン（メタ）アクリレート（ｂ１）を得ることができる。ヒドロキシ基を有する（メタ）アクリレートとしては、少なくとも１分子中にヒドロキシ基及び（メタ）アクリロイル基を有する化合物であれば、特に限定されない。 A urethane (meth)acrylate (b1) can be obtained by reacting a (meth)acrylate having a hydroxyl group with a terminal isocyanate urethane prepolymer obtained by reacting the above-mentioned polyol compound and a polyvalent isocyanate compound. The (meth)acrylate having a hydroxy group is not particularly limited as long as it is a compound having a hydroxy group and a (meth)acryloyl group in at least one molecule.
　具体的なヒドロキシ基を有する（メタ）アクリレートとしては、例えば、２－ヒドロキシエチル（メタ）アクリレート、２－ヒドロキシプロピル（メタ）アクリレート、４－ヒドロキシブチル（メタ）アクリレート、４－ヒドロキシシクロヘキシル（メタ）アクリレート、５－ヒドロキシシクロオクチル（メタ）アクリレート、２－ヒドロキシ－３－フェニルオキシプロピル（メタ）アクリレート、ペンタエリスリトールトリ（メタ）アクリレート、ポリエチレングリコールモノ（メタ）アクリレート、ポリプロピレングリコールモノ（メタ）アクリレート等のヒドロキシアルキル（メタ）アクリレート；Ｎ－メチロール（メタ）アクリルアミド等のヒドロキシ基含有（メタ）アクリルアミド；ビニルアルコール、ビニルフェノール、ビスフェノールＡのジグリシジルエステルに（メタ）アクリル酸を反応させて得られる反応物；等が挙げられる。 Specific (meth)acrylates having a hydroxy group include, for example, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 4-hydroxycyclohexyl (meth) Acrylate, 5-hydroxycyclooctyl (meth)acrylate, 2-hydroxy-3-phenyloxypropyl (meth)acrylate, pentaerythritol tri(meth)acrylate, polyethylene glycol mono(meth)acrylate, polypropylene glycol mono(meth)acrylate, etc. hydroxyalkyl (meth)acrylate; hydroxy group-containing (meth)acrylamide such as N-methylol (meth)acrylamide; vinyl alcohol, vinylphenol, reaction obtained by reacting diglycidyl ester of bisphenol A with (meth)acrylic acid things; and the like.
　これらの中でも、ヒドロキシアルキル（メタ）アクリレートが好ましく、２－ヒドロキシエチル（メタ）アクリレートがより好ましい。 Among these, hydroxyalkyl (meth)acrylates are preferred, and 2-hydroxyethyl (meth)acrylate is more preferred.
　緩衝層用組成物中の成分（ｂ１）の含有量は、緩衝層用組成物の全量（１００質量％）に対して、好ましくは１０～７０質量％、より好ましくは２０～６０質量％、さらに好ましくは２５～５５質量％である。 The content of component (b1) in the buffer layer composition is preferably 10 to 70% by mass, more preferably 20 to 60% by mass, based on the total amount (100% by mass) of the buffer layer composition. It is preferably 25 to 55% by mass.
　（５．１．２　環形成原子数６～２０の脂環基又は複素環基を有する重合性化合物（ｂ２））
　成分（ｂ２）は、環形成原子数６～２０の脂環基又は複素環基を有する重合性化合物であり、さらには、少なくとも１つの（メタ）アクリロイル基を有する化合物であることが好ましく、より好ましくは１つの（メタ）アクリロイル基を有する化合物である。成分（ｂ２）を用いることで、得られる緩衝層用組成物の成膜性を向上させることができる。 (5.1.2 Polymerizable Compound (b2) Having an Alicyclic or Heterocyclic Group Having 6 to 20 Ring-forming Atoms)
Component (b2) is a polymerizable compound having an alicyclic or heterocyclic group having 6 to 20 ring atoms, and more preferably a compound having at least one (meth)acryloyl group. Compounds having one (meth)acryloyl group are preferred. By using the component (b2), it is possible to improve the film formability of the obtained buffer layer composition.
　具体的な成分（ｂ２）としては、例えば、イソボルニル（メタ）アクリレート、ジシクロペンテニル（メタ）アクリレート、ジシクロペンタニル（メタ）アクリレート、ジシクロペンテニルオキシ（メタ）アクリレート、シクロヘキシル（メタ）アクリレート、アダマンタン（メタ）アクリレート等の脂環基含有（メタ）アクリレート；テトラヒドロフルフリル（メタ）アクリレート、モルフォリン（メタ）アクリレート等の複素環基含有（メタ）アクリレート；等が挙げられる。なお、成分（ｂ２）は、単独で又は２種以上を組み合わせて用いてもよい。脂環基含有（メタ）アクリレートの中ではイソボルニル（メタ）アクリレートが好ましく、複素環基含有（メタ）アクリレートの中ではテトラヒドロフルフリル（メタ）アクリレートが好ましい。 Specific components (b2) include, for example, isobornyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentenyloxy (meth)acrylate, cyclohexyl (meth)acrylate, alicyclic group-containing (meth)acrylates such as adamantane (meth)acrylate; heterocyclic group-containing (meth)acrylates such as tetrahydrofurfuryl (meth)acrylate and morpholine (meth)acrylate; and the like. In addition, you may use a component (b2) individually or in combination of 2 or more types. Among alicyclic group-containing (meth)acrylates, isobornyl (meth)acrylate is preferred, and among heterocyclic group-containing (meth)acrylates, tetrahydrofurfuryl (meth)acrylate is preferred.
　緩衝層用組成物中の成分（ｂ２）の含有量は、緩衝層用組成物の全量（１００質量％）に対して、好ましくは１０～７０質量％、より好ましくは２０～６０質量％、さらに好ましくは２５～５５質量％である。 The content of the component (b2) in the buffer layer composition is preferably 10 to 70% by mass, more preferably 20 to 60% by mass, based on the total amount (100% by mass) of the buffer layer composition. It is preferably 25 to 55% by mass.
　（５．１．３　官能基を有する重合性化合物（ｂ３））
　成分（ｂ３）は、水酸基、エポキシ基、アミド基、アミノ基等の官能基を含有する重合性化合物であり、さらには、少なくとも１つの（メタ）アクリロイル基を有する化合物であることが好ましく、より好ましくは１つの（メタ）アクリロイル基を有する化合物である。 (5.1.3 Polymerizable compound having a functional group (b3))
Component (b3) is a polymerizable compound containing a functional group such as a hydroxyl group, an epoxy group, an amide group, or an amino group, and is preferably a compound having at least one (meth)acryloyl group. Compounds having one (meth)acryloyl group are preferred.
　成分（ｂ３）は、成分（ｂ１）との相溶性が良好であり、緩衝層用組成物の粘度を適度な範囲に調整しやすくなる。また、緩衝層を比較的薄くしても緩衝性能が良好になる。 The component (b3) has good compatibility with the component (b1), and it becomes easy to adjust the viscosity of the buffer layer composition to an appropriate range. Moreover, even if the buffer layer is made relatively thin, the buffer performance is improved.
　成分（ｂ３）としては、例えば、水酸基含有（メタ）アクリレート、エポキシ基含有化合物、アミド基含有化合物、アミノ基含有（メタ）アクリレート等が挙げられる。これらの中でも、水酸基含有（メタ）アクリレートが好ましい。 Examples of component (b3) include hydroxyl group-containing (meth)acrylates, epoxy group-containing compounds, amide group-containing compounds, amino group-containing (meth)acrylates, and the like. Among these, hydroxyl group-containing (meth)acrylates are preferred.
　水酸基含有（メタ）アクリレートとしては、例えば、２－ヒドロキシエチル（メタ）アクリレート、２－ヒドロキシプロピル（メタ）アクリレート、３－ヒドロキシプロピル（メタ）アクリレート、２－ヒドロキシブチル（メタ）アクリレート、３－ヒドロキシブチル（メタ）アクリレート、４－ヒドロキシブチル（メタ）アクリレート、フェニルヒドロキシプロピル（メタ）アクリレート、２－ヒドロキシー３－フェノキシプロピルアクリレート等が挙げられる。これらの中でも、フェニルヒドロキシプロピル（メタ）アクリレート等の芳香環を有する水酸基含有（メタ）アクリレートがより好ましい。 Examples of hydroxyl group-containing (meth)acrylates include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxy Butyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, phenylhydroxypropyl (meth)acrylate, 2-hydroxy-3-phenoxypropyl acrylate and the like. Among these, hydroxyl group-containing (meth)acrylates having an aromatic ring such as phenylhydroxypropyl (meth)acrylate are more preferable.
　なお、成分（ｂ３）は、単独で又は２種以上を組み合わせて用いてもよい。緩衝層用組成物中の成分（ｂ３）の含有量は、緩衝層用組成物の成膜性を向上させるために、緩衝層用組成物の全量（１００質量％）に対して、好ましくは５～４０質量％、より好ましくは７～３５質量％、さらに好ましくは１０～３０質量％である。 Note that the component (b3) may be used alone or in combination of two or more. The content of the component (b3) in the buffer layer composition is preferably 5% with respect to the total amount (100% by mass) of the buffer layer composition in order to improve the film-forming properties of the buffer layer composition. ~40% by mass, more preferably 7 to 35% by mass, still more preferably 10 to 30% by mass.
　（５．１．４　成分（ｂ１）～（ｂ３）以外の重合性化合物（ｂ４））
　緩衝層形成用組成物には、本発明の効果を損なわない範囲において、上記の成分（ｂ１）～（ｂ３）以外のその他の重合性化合物（ｂ４）を含有してもよい。 (5.1.4 Polymerizable compound (b4) other than components (b1) to (b3))
The buffer layer-forming composition may contain a polymerizable compound (b4) other than the components (b1) to (b3) as long as the effects of the present invention are not impaired.
　成分（ｂ４）としては、例えば、炭素数１～２０のアルキル基を有するアルキル（メタ）アクリレート；スチレン、ヒドロキシエチルビニルエーテル、ヒドロキシブチルビニルエーテル、Ｎ－ビニルホルムアミド、Ｎ－ビニルピロリドン、Ｎ－ビニルカプロラクタム等のビニル化合物：等が挙げられる。なお、成分（ｂ４）は、単独で又は２種以上を組み合わせて用いてもよい。 Examples of component (b4) include alkyl (meth)acrylates having an alkyl group having 1 to 20 carbon atoms; styrene, hydroxyethyl vinyl ether, hydroxybutyl vinyl ether, N-vinylformamide, N-vinylpyrrolidone, N-vinylcaprolactam, and the like. vinyl compound of: and the like. In addition, you may use a component (b4) individually or in combination of 2 or more types.
　緩衝層形成用組成物中の成分（ｂ４）の含有量は、好ましくは０～２０質量％、より好ましくは０～１０質量％、さらに好ましくは０～５質量％、特に好ましくは０～２質量％である。 The content of component (b4) in the buffer layer-forming composition is preferably 0 to 20% by mass, more preferably 0 to 10% by mass, even more preferably 0 to 5% by mass, and particularly preferably 0 to 2% by mass. %.
　（５．１．５　光重合開始剤）
　緩衝層用組成物には、緩衝層を形成する際、エネルギー線照射による重合時間を短縮させ、また、エネルギー線照射量を低減させる観点から、さらに光重合開始剤を含有することが好ましい。 (5.1.5 Photoinitiator)
The buffer layer composition preferably further contains a photopolymerization initiator from the viewpoint of shortening the polymerization time by energy ray irradiation and reducing the amount of energy ray irradiation when forming the buffer layer.
　光重合開始剤としては、例えば、ベンゾイン化合物、アセトフェノン化合物、アシルフォスフィノキサイド化合物、チタノセン化合物、チオキサントン化合物、パーオキサイド化合物、さらには、アミンやキノン等の光増感剤等が挙げられ、より具体的には、例えば、１－ヒドロキシシクロヘキシルフェニルケトン、２－ヒドロキシ－２－メチル－１－フェニル－プロパン－１－オン、ベンゾイン、ベンゾインメチルエーテル、ベンゾインエチルエーテル、ベンゾインイソプロピルエーテル、ベンジルフェニルサルファイド、テトラメチルチウラムモノサルファイド、アゾビスイソブチロルニトリル、ジベンジル、ジアセチル、８－クロールアンスラキノン、ビス（２，４，６－トリメチルベンゾイル）フェニルフォスフィンオキシド等が挙げられる。 Examples of photopolymerization initiators include benzoin compounds, acetophenone compounds, acylphosphine oxide compounds, titanocene compounds, thioxanthone compounds, peroxide compounds, and photosensitizers such as amines and quinones. Specifically, for example, 1-hydroxycyclohexylphenyl ketone, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzylphenyl sulfide, tetramethylthiuram monosulfide, azobisisobutyrolnitrile, dibenzyl, diacetyl, 8-chloroanthraquinone, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide and the like.
　これらの光重合開始剤は、単独で又は２種以上を組み合わせて用いることができる。 These photopolymerization initiators can be used alone or in combination of two or more.
　緩衝層用組成物中の光重合開始剤の含有量は、エネルギー線重合性化合物の合計量１００質量部に対して、好ましくは０．０５～１５質量部、より好ましくは０．１～１０質量部、さらに好ましくは０．３～５質量部である。 The content of the photopolymerization initiator in the buffer layer composition is preferably 0.05 to 15 parts by mass, more preferably 0.1 to 10 parts by mass, with respect to 100 parts by mass of the total amount of the energy ray-polymerizable compound. parts, more preferably 0.3 to 5 parts by mass.
　（５．１．６　その他の添加剤）
　緩衝層用組成物には、本発明の効果を損なわない範囲において、その他の添加剤を含有してもよい。その他の添加剤としては、例えば、帯電防止剤、酸化防止剤、軟化剤（可塑剤）、充填剤、防錆剤、顔料、染料等が挙げられる。これらの添加剤を配合する場合、緩衝層用組成物中の各添加剤の含有量は、エネルギー線重合性化合物の合計量１００質量部に対して、好ましくは０．０１～６質量部、より好ましくは０．１～３質量部である。 (5.1.6 Other Additives)
The buffer layer composition may contain other additives as long as the effects of the present invention are not impaired. Other additives include, for example, antistatic agents, antioxidants, softeners (plasticizers), fillers, rust inhibitors, pigments, dyes, and the like. When these additives are blended, the content of each additive in the buffer layer composition is preferably 0.01 to 6 parts by mass, more than It is preferably 0.1 to 3 parts by mass.
　エネルギー線重合性化合物を含む緩衝層用組成物から形成される緩衝層は、上記組成の緩衝層用組成物をエネルギー線照射により重合硬化して得られる。つまり、当該緩衝層は、緩衝層用組成物の硬化物である。 The buffer layer formed from the buffer layer composition containing the energy ray-polymerizable compound is obtained by polymerizing and curing the buffer layer composition having the above composition by energy ray irradiation. That is, the buffer layer is a hardened material of the buffer layer composition.
　したがって、当該緩衝層は、成分（ｂ１）由来の重合単位及び成分（ｂ２）由来の重合単位を含むことが好ましい。また、当該緩衝層は、成分（ｂ３）由来の重合単位を含有していてもよいし、成分（ｂ４）由来の重合単位を含有していてもよい。緩衝層における各重合単位の含有割合は、通常、緩衝層用組成物を構成する各成分の比率（仕込み比）に一致する。 Therefore, the buffer layer preferably contains polymerized units derived from component (b1) and polymerized units derived from component (b2). Moreover, the buffer layer may contain a polymerized unit derived from the component (b3) or may contain a polymerized unit derived from the component (b4). The content ratio of each polymer unit in the buffer layer usually corresponds to the ratio (feed ratio) of each component constituting the composition for the buffer layer.
　（６．剥離シート）
　半導体加工用保護シートの表面には、剥離シートが貼付されていてもよい。剥離シートは、具体的には、半導体加工用保護シートの粘着剤層の表面に貼付される。剥離シートは、粘着剤層表面に貼付されることで輸送時、保管時に粘着剤層を保護する。剥離シートは、剥離可能に半導体加工用保護シートに貼付されており、半導体加工用保護シートが使用される前（すなわち、ウエハ貼付前）には、半導体加工用保護シートから剥離されて取り除かれる。 (6. Release sheet)
A release sheet may be attached to the surface of the protective sheet for semiconductor processing. Specifically, the release sheet is attached to the surface of the pressure-sensitive adhesive layer of the protective sheet for semiconductor processing. The release sheet is attached to the surface of the adhesive layer to protect the adhesive layer during transportation and storage. The release sheet is releasably attached to the semiconductor processing protective sheet, and is peeled off and removed from the semiconductor processing protective sheet before the semiconductor processing protective sheet is used (that is, before the wafer is attached).
　剥離シートは、少なくとも一方の面が剥離処理をされた剥離シートが用いられ、具体的には、剥離シート用基材の表面上に剥離剤を塗布したもの等が挙げられる。 As the release sheet, a release sheet having at least one surface subjected to a release treatment is used, and specific examples include a release sheet base material coated with a release agent on the surface.
　剥離シート用基材としては、樹脂フィルムが好ましく、当該樹脂フィルムを構成する樹脂としては、例えば、ポリエチレンテレフタレート樹脂、ポリブチレンテレフタレート樹脂、ポリエチレンナフタレート樹脂等のポリエステル樹脂フィルム、ポリプロピレン樹脂、ポリエチレン樹脂等のポリオレフィン樹脂等が挙げられる。剥離剤としては、例えば、シリコーン系樹脂、オレフィン系樹脂、イソプレン系樹脂、ブタジエン系樹脂等のゴム系エラストマー、長鎖アルキル系樹脂、アルキド系樹脂、フッ素系樹脂等が挙げられる。 As the substrate for the release sheet, a resin film is preferable, and as the resin constituting the resin film, for example, polyester resin films such as polyethylene terephthalate resin, polybutylene terephthalate resin, polyethylene naphthalate resin, polypropylene resin, polyethylene resin, etc. and the like polyolefin resins. Examples of release agents include rubber-based elastomers such as silicone-based resins, olefin-based resins, isoprene-based resins and butadiene-based resins, long-chain alkyl-based resins, alkyd-based resins, fluorine-based resins, and the like.
　剥離シートの厚さは、特に制限ないが、好ましくは１０～２００μｍ、より好ましくは２０～１５０μｍである。 Although the thickness of the release sheet is not particularly limited, it is preferably 10 to 200 μm, more preferably 20 to 150 μm.
　（７．半導体加工用保護シートの製造方法）
　本実施形態に係る半導体加工用保護シートを製造する方法は、基材の主面上に帯電防止層、緩衝層および粘着剤層を形成できる方法であれば特に制限されず、公知の方法を用いればよい。以下では、図１Ａに示す半導体加工用保護シートを製造する方法について説明する。 (7. Manufacturing method of protective sheet for semiconductor processing)
The method for producing the protective sheet for semiconductor processing according to the present embodiment is not particularly limited as long as it is a method capable of forming an antistatic layer, a buffer layer and an adhesive layer on the main surface of the substrate, and a known method can be used. Just do it. A method of manufacturing the protective sheet for semiconductor processing shown in FIG. 1A will be described below.
　まず、帯電防止層を形成するための組成物として、たとえば、上述した成分を含有する帯電防止層用組成物、または、当該帯電防止層用組成物を溶媒等により希釈した組成物を調製する。同様に、粘着剤層を形成するための粘着剤層用組成物として、たとえば、上述した成分を含有する粘着剤層用組成物、または、当該粘着剤層用組成物を溶媒等により希釈した組成物を調製する。同様に、緩衝層を形成するための緩衝層用組成物として、たとえば、上述した成分を含有する緩衝層用組成物、または、当該緩衝層用組成物を溶媒等により希釈した組成物を調製する。 First, as a composition for forming an antistatic layer, for example, an antistatic layer composition containing the above-described components or a composition obtained by diluting the antistatic layer composition with a solvent or the like is prepared. Similarly, the adhesive layer composition for forming the adhesive layer may be, for example, a pressure-sensitive adhesive layer composition containing the above-described components, or a composition obtained by diluting the pressure-sensitive adhesive layer composition with a solvent or the like. prepare things. Similarly, as the buffer layer composition for forming the buffer layer, for example, a buffer layer composition containing the above-described components, or a composition obtained by diluting the buffer layer composition with a solvent or the like is prepared. .
　溶媒としては、たとえば、メチルエチルケトン、アセトン、酢酸エチル、テトラヒドロフラン、ジオキサン、シクロヘキサン、ｎ－ヘキサン、トルエン、キシレン、ｎ－プロパノール、イソプロパノール等の有機溶剤が挙げられる。 Examples of solvents include organic solvents such as methyl ethyl ketone, acetone, ethyl acetate, tetrahydrofuran, dioxane, cyclohexane, n-hexane, toluene, xylene, n-propanol and isopropanol.
　そして、第１の剥離シートの剥離処理面に緩衝層用組成物を、スピンコート法、スプレーコート法、バーコート法、ナイフコート法、ロールコート法、ブレードコート法、ダイコート法、グラビアコート法等の公知の方法により塗布して塗布膜を形成し、この塗布膜を半硬化させて剥離シート上に緩衝層膜を形成する。剥離シート上に形成した緩衝層膜を基材の一方の面に貼り合わせて、緩衝層膜を完全に硬化させて、基材上に緩衝層を形成する。 Then, the buffer layer composition is applied to the release-treated surface of the first release sheet by a spin coating method, a spray coating method, a bar coating method, a knife coating method, a roll coating method, a blade coating method, a die coating method, a gravure coating method, or the like. A coating film is formed by coating by a known method, and this coating film is semi-cured to form a buffer layer film on a release sheet. The buffer layer film formed on the release sheet is adhered to one surface of the substrate, and the buffer layer film is completely cured to form a buffer layer on the substrate.
　本実施形態では、塗布膜の硬化は、エネルギー線の照射により行うことが好ましい。また、塗布膜の硬化は、一度の硬化処理で行ってもよいし、複数回に分けて行ってもよい。 In the present embodiment, the coating film is preferably cured by irradiation with energy rays. Moreover, the curing of the coating film may be performed in one curing process, or may be performed in a plurality of times.
　続いて、第２の剥離シートの剥離処理面に、帯電防止層用組成物を公知の方法により塗布して加熱乾燥して第２の剥離シート上に帯電防止層を形成する。その後、第２の剥離シート上の帯電防止層と緩衝層が形成されていない基材の面とを貼り合わせて、第２の剥離シートを除去する。 Subsequently, an antistatic layer composition is applied to the release-treated surface of the second release sheet by a known method and dried by heating to form an antistatic layer on the second release sheet. After that, the antistatic layer on the second release sheet and the surface of the substrate on which the buffer layer is not formed are attached together, and the second release sheet is removed.
　続いて、第３の剥離シートの剥離処理面に、粘着剤層用組成物を公知の方法により塗布し、加熱乾燥して第３の剥離シート上に粘着剤層を形成する。その後、第３の剥離シート上の粘着剤層と、基材上の帯電防止層とを貼り合わせることにより、基材の一方の主面上に帯電防止層および粘着剤層がこの順で形成され、基材の他方の主面上に緩衝層が形成された半導体加工用保護シートが得られる。なお、第３の剥離シートは、半導体加工用保護シートの使用時に除去すればよい。 Subsequently, the adhesive layer composition is applied to the release-treated surface of the third release sheet by a known method and dried by heating to form an adhesive layer on the third release sheet. After that, the adhesive layer on the third release sheet and the antistatic layer on the base material are laminated to form an antistatic layer and an adhesive layer in this order on one main surface of the base material. , a protective sheet for semiconductor processing having a buffer layer formed on the other main surface of the substrate is obtained. The third release sheet may be removed when using the protective sheet for semiconductor processing.
　（８．半導体装置の製造方法）
　本発明に係る半導体加工用保護シートは、ＤＢＧにおいて、半導体ウエハの表面に貼付してウエハの裏面研削が行われる際に好ましく使用される。特に、本発明に係る半導体加工用保護シートは、半導体ウエハを個片化した際に、カーフ幅の小さいチップ群が得られるＬＤＢＧに好ましく使用される。 (8. Manufacturing method of semiconductor device)
The protective sheet for semiconductor processing according to the present invention is preferably used in DBG when the back surface of the wafer is ground by being attached to the front surface of the semiconductor wafer. In particular, the protective sheet for semiconductor processing according to the present invention is preferably used for LDBG in which a chip group with a small kerf width can be obtained when a semiconductor wafer is singulated.
　半導体加工用保護シートの非限定的な使用例として、以下に半導体装置の製造方法をさらに具体的に説明する。 As a non-limiting example of use of the protective sheet for semiconductor processing, the method for manufacturing a semiconductor device will be described in more detail below.
　半導体装置の製造方法は、具体的には、以下の工程１～工程４を少なくとも備える。
工程１：上記の半導体加工用保護シートを、半導体ウエハの表面に貼付する工程
工程２：当該半導体ウエハの表面側から溝を形成し、又は当該半導体ウエハの表面若しくは裏面から当該半導体ウエハ内部に改質領域を形成する工程
工程３：半導体加工用保護シートが表面に貼付され、かつ上記溝又は改質領域が形成された半導体ウエハを、裏面側から研削して、溝又は改質領域を起点として、複数のチップに個片化させる工程
工程４：個片化された半導体ウエハ（すなわち、チップ群）から、半導体加工用保護シートを剥離する工程 Specifically, the method for manufacturing a semiconductor device includes at least steps 1 to 4 below.
Step 1: Affixing the protective sheet for semiconductor processing to the surface of the semiconductor wafer Step 2: Forming a groove from the front surface side of the semiconductor wafer, or reforming the inside of the semiconductor wafer from the front surface or the back surface of the semiconductor wafer Step 3: The semiconductor wafer on which the protective sheet for semiconductor processing is attached to the surface and the grooves or modified regions are formed is ground from the back side, and the grooves or modified regions are used as starting points. , a step of singulating into a plurality of chips Step 4: A step of peeling off the protective sheet for semiconductor processing from the singulated semiconductor wafer (that is, chip group)
　以下、上記半導体装置の製造方法の各工程を詳細に説明する。 Each step of the method for manufacturing the semiconductor device will be described in detail below.
　（工程１）
　工程１では、図２に示すように、半導体ウエハ１００の表面１００ａに、本実施形態に係る半導体加工用保護シート１の粘着剤層３０の主面３０ａを貼付する。半導体加工用保護シートを半導体ウエハの表面に貼付することにより、半導体ウエハの表面が十分に保護される。 (Step 1)
In step 1, as shown in FIG. 2, the main surface 30a of the adhesive layer 30 of the protective sheet for semiconductor processing 1 according to the present embodiment is attached to the surface 100a of the semiconductor wafer 100 . By attaching the protective sheet for semiconductor processing to the surface of the semiconductor wafer, the surface of the semiconductor wafer is sufficiently protected.
　本工程は、後述する工程２の前に行ってもよいし、工程２の後に行ってもよい。例えば、半導体ウエハに改質領域を形成する場合には、工程１を工程２の前に行うことが好ましい。一方、半導体ウエハ表面に、ダイシング等により溝を形成する場合には、工程２の後に工程１を行う。すなわち、後述する工程２で形成した溝を有するウエハの表面に、本工程１にて半導体加工用保護シートを貼付することになる。 This step may be performed before step 2, which will be described later, or after step 2. For example, when forming a modified region on a semiconductor wafer, step 1 is preferably performed before step 2. On the other hand, when grooves are formed on the surface of a semiconductor wafer by dicing or the like, step 1 is performed after step 2. FIG. That is, in step 1, a protective sheet for semiconductor processing is attached to the surface of the wafer having grooves formed in step 2, which will be described later.
　本製造方法で用いられる半導体ウエハはシリコンウエハであってもよいし、またガリウム砒素、炭化ケイ素、タンタル酸リチウム、ニオブ酸リチウム、窒化ガリウム、インジウム燐などのウエハや、ガラスウエハであってもよい。本実施形態では、半導体ウエハはシリコンウエハであることが好ましい。 The semiconductor wafer used in this manufacturing method may be a silicon wafer, a wafer of gallium arsenide, silicon carbide, lithium tantalate, lithium niobate, gallium nitride, indium phosphide, or the like, or a glass wafer. . In this embodiment, the semiconductor wafer is preferably a silicon wafer.
　半導体ウエハの研削前の厚さは特に限定されないが、通常は５００～１０００μｍ程度である。また、半導体ウエハは、通常、その表面に回路が形成されている。ウエハ表面への回路の形成は、エッチング法、リフトオフ法などの従来汎用されている方法を含む様々な方法により行うことができる。 Although the thickness of the semiconductor wafer before grinding is not particularly limited, it is usually about 500 to 1000 μm. A semiconductor wafer usually has a circuit formed on its surface. Formation of circuits on the wafer surface can be performed by various methods including conventional methods such as an etching method and a lift-off method.
　（工程２）
　工程２では、半導体ウエハの表面側から溝を形成する。あるいは、半導体ウエハの表面若しくは裏面から半導体ウエハの内部に改質領域を形成する。 (Step 2)
In step 2, grooves are formed from the front surface side of the semiconductor wafer. Alternatively, a modified region is formed inside the semiconductor wafer from the front surface or rear surface of the semiconductor wafer.
　本工程で形成される溝は、半導体ウエハの厚さより浅い深さの溝である。溝の形成は、従来公知のウエハダイシング装置等を用いてダイシングにより行うことが可能である。また、半導体ウエハは、後述する工程３において、溝に沿って複数の半導体チップに分割される。 The grooves formed in this process are shallower than the thickness of the semiconductor wafer. The grooves can be formed by dicing using a conventionally known wafer dicing device or the like. Also, the semiconductor wafer is divided into a plurality of semiconductor chips along the grooves in step 3, which will be described later.
　また、改質領域は、半導体ウエハにおいて、脆質化された部分であり、研削工程における研削によって、半導体ウエハが薄くなったり、研削による力が加わったりすることにより半導体ウエハの改質領域が破壊されて半導体チップに個片化される起点となる領域である。すなわち、工程２において溝及び改質領域は、後述する工程３において、半導体ウエハが分割されて半導体チップに個片化される際の分割線に沿うように形成される。 In addition, the modified region is an embrittled portion of the semiconductor wafer, and the semiconductor wafer is thinned by grinding in the grinding process, and the modified region of the semiconductor wafer is destroyed by the application of grinding force. It is a starting point for separating into semiconductor chips. That is, in step 2, the grooves and modified regions are formed along dividing lines along which the semiconductor wafer is divided into individual semiconductor chips in step 3, which will be described later.
　改質領域の形成は、半導体ウエハの内部に焦点を合わせたレーザーの照射により行い、改質領域は、半導体ウエハの内部に形成される。レーザーの照射は、半導体ウエハの表面側から行っても、裏面側から行ってもよい。なお、改質領域を形成する態様において、工程２を工程１の後に行いウエハ表面からレーザー照射を行う場合、半導体加工用保護シートを介して半導体ウエハにレーザーを照射することになる。 The modified region is formed by laser irradiation focused on the inside of the semiconductor wafer, and the modified region is formed inside the semiconductor wafer. The laser irradiation may be performed from the front side or the back side of the semiconductor wafer. In the mode of forming the modified region, when step 2 is performed after step 1 and laser irradiation is performed from the wafer surface, the semiconductor wafer is irradiated with the laser through the protective sheet for semiconductor processing.
　半導体加工用保護シートが貼付され、かつ溝又は改質領域を形成した半導体ウエハは、チャックテーブル上に載せられ、チャックテーブルに吸着されて保持される。この際、半導体ウエハは、表面側がテーブル側に配置されて吸着される。 A semiconductor wafer on which a semiconductor processing protection sheet is attached and grooves or modified regions are formed is placed on a chuck table, and is held by being sucked by the chuck table. At this time, the semiconductor wafer is sucked with its surface side arranged on the table side.
　（工程３）
　工程１及び工程２の後、チャックテーブル上の半導体ウエハの裏面を研削して、半導体ウエハを複数の半導体チップに個片化して、チップ群が得られる。 (Step 3)
After steps 1 and 2, the back surface of the semiconductor wafer on the chuck table is ground to singulate the semiconductor wafer into a plurality of semiconductor chips to obtain a chip group.
　ここで、裏面研削は、半導体ウエハに溝が形成される場合には、少なくとも溝の底部に至る位置まで半導体ウエハを薄くするように行う。この裏面研削により、溝は、ウエハを貫通する切り込みとなり、半導体ウエハは切り込みにより分割されて、個々の半導体チップに個片化される。 Here, when grooves are formed in the semiconductor wafer, the back surface grinding is performed so as to thin the semiconductor wafer at least to the position reaching the bottom of the groove. By this back-grinding, the grooves become cuts penetrating the wafer, and the semiconductor wafer is divided by the cuts into individual semiconductor chips.
　一方、改質領域が形成される場合には、研削によって研削面（ウエハ裏面）は、改質領域に至ってもよいが、厳密に改質領域まで至らなくてもよい。すなわち、改質領域を起点として半導体ウエハが破壊されて半導体チップに個片化されるように、改質領域に近接する位置まで研削すればよい。例えば、半導体チップの実際の個片化は、後述するピックアップテープを貼付してからピックアップテープを延伸することで行ってもよい。 On the other hand, when the modified region is formed, the ground surface (wafer back surface) may reach the modified region by grinding, but it does not have to reach the modified region strictly. That is, the semiconductor wafer may be ground from the modified region to a position close to the modified region so that the semiconductor wafer is broken into individual semiconductor chips starting from the modified region. For example, the actual singulation of the semiconductor chips may be performed by applying a pick-up tape, which will be described later, and then stretching the pick-up tape.
　また、裏面研削の終了後、チップのピックアップに先立ち、ドライポリッシュを行ってもよい。 Also, after the backside grinding is completed, dry polishing may be performed prior to picking up the chips.
　個片化された半導体チップの形状は、方形でもよいし、矩形等の細長形状となっていてもよい。また、個片化された半導体チップの厚さは特に限定されないが、好ましくは５～１００μｍ程度であるが、より好ましくは１０～４５μｍである。レーザーでウエハ内部に改質領域を設け、ウエハ裏面研削時の応力等でウエハの個片化を行う、ＬＤＢＧによれば、個片化された半導体チップの厚さを５０μｍ以下、より好ましくは１０～４５μｍとすることが容易になる。また、個片化された半導体チップの大きさは、特に限定されないが、チップサイズが好ましくは６００ｍｍ２未満、より好ましくは４００ｍｍ２未満、さらに好ましくは１２０ｍｍ２未満である。 The shape of the individualized semiconductor chips may be a square or an elongated shape such as a rectangle. Although the thickness of the individualized semiconductor chips is not particularly limited, it is preferably about 5 to 100 μm, more preferably 10 to 45 μm. According to LDBG, a modified region is provided inside the wafer with a laser, and the wafer is singulated by stress or the like during wafer backside grinding. ∼45 μm becomes easy. The size of the individualized semiconductor chips is not particularly limited, but the chip size is preferably less than 600 mm 2 , more preferably less than 400 mm 2 , still more preferably less than 120 mm 2 .
　本実施形態に係る半導体加工用保護シートを使用すると、薄型及び／又は小型の半導体チップであっても、裏面研削時（工程３）、及び半導体加工用保護シート剥離時（工程４）に帯電が防止され、かつ半導体チップにクラックが生じることが防止される。 When the protective sheet for semiconductor processing according to the present embodiment is used, even a thin and/or small semiconductor chip is charged during back grinding (step 3) and during peeling of the protective sheet for semiconductor processing (step 4). This prevents cracks from occurring in the semiconductor chip.
　（工程４）
　次に、個片化された半導体ウエハ（すなわち、複数の半導体チップ）から、半導体加工用保護シートを剥離する。本工程は、例えば、以下の方法により行う。 (Step 4)
Next, the protective sheet for semiconductor processing is peeled off from the individualized semiconductor wafer (that is, a plurality of semiconductor chips). This step is performed, for example, by the following method.
　本実施形態では、半導体加工用保護シートの粘着剤層が、エネルギー線硬化性粘着剤から形成されているので、エネルギー線を照射して粘着剤層を硬化収縮させ、被着体（個片化された半導体ウエハ）に対する粘着力を低下させる。次いで、個片化された半導体ウエハの裏面側に、ピックアップテープを貼付し、ピックアップが可能なように位置及び方向合わせを行う。この際、ウエハの外周側に配置したリングフレームもピックアープテープに貼り合わせ、ピックアップテープの外周縁部をリングフレームに固定する。ピックアップテープには、ウエハとリングフレームを同時に貼り合わせてもよいし、別々のタイミングで貼り合わせてもよい。次いで、ピックアップテープ上に保持された複数の半導体チップから半導体加工用保護シートを剥離する。 In this embodiment, since the adhesive layer of the protective sheet for semiconductor processing is formed from an energy ray-curable adhesive, the adhesive layer is cured and shrunk by irradiating the energy ray, and the adherend (individualized) (semiconductor wafer). Next, a pick-up tape is attached to the rear surface side of the separated semiconductor wafer, and the position and direction are aligned so that pick-up is possible. At this time, the ring frame arranged on the outer peripheral side of the wafer is also adhered to the pick-up tape, and the outer peripheral edge of the pick-up tape is fixed to the ring frame. The wafer and the ring frame may be attached to the pickup tape at the same time, or may be attached at separate timings. Next, the protective sheet for semiconductor processing is peeled off from the plurality of semiconductor chips held on the pickup tape.
　本実施形態に係る半導体加工用保護シートは上述した特性を有しているので、半導体加工用保護シートを半導体ウエハから剥離する際の剥離速度が速くても、帯電が抑制され、かつ半導体ウエハ等に糊残りが生じず、チップ同士の接触が抑制された状態で剥離を行うことができる。 Since the protective sheet for semiconductor processing according to the present embodiment has the above-described properties, even when the protective sheet for semiconductor processing is peeled off from a semiconductor wafer at a high peeling speed, electrification is suppressed and the semiconductor wafer, etc. The peeling can be performed in a state in which the contact between the chips is suppressed without leaving any adhesive residue.
　その後、ピックアップテープ上にある複数の半導体チップをピックアップし基板等の上に固定化して、半導体装置を製造する。 After that, multiple semiconductor chips on the pickup tape are picked up and fixed on a substrate or the like to manufacture a semiconductor device.
　なお、ピックアップテープは、特に限定されないが、例えば、基材と、基材の一方の面に設けられた粘着剤層を備える粘着シートによって構成される。 Although the pickup tape is not particularly limited, it is composed of, for example, a base material and an adhesive sheet having an adhesive layer provided on one side of the base material.
　以上、本発明に係る半導体加工用保護シートについて、ＤＢＧまたはＬＤＢＧにより半導体ウエハを個片化する方法に使用する例について説明したが、本発明に係る半導体加工用保護シートは、半導体ウエハを個片化した際に、カーフ幅の小さく、より薄化されたチップ群が得られるＬＤＢＧに好ましく使用できる。 As described above, the protective sheet for semiconductor processing according to the present invention is used in a method for singulating semiconductor wafers by DBG or LDBG. It can be preferably used for LDBG in which a thinned chip group with a small kerf width is obtained.
　以上、本発明の実施形態について説明してきたが、本発明は上記の実施形態に何ら限定されるものではなく、本発明の範囲内において種々の態様で改変しても良い。 Although the embodiments of the present invention have been described above, the present invention is by no means limited to the above embodiments, and may be modified in various ways within the scope of the present invention.
　以下、実施例を用いて、発明をより詳細に説明するが、本発明はこれらの実施例に限定されるものではない。 The invention will be described in more detail below using examples, but the invention is not limited to these examples.
　本実施例における測定方法および評価方法は以下の通りである。 The measurement method and evaluation method in this example are as follows.
　（エネルギー線硬化後の粘着剤層の表面抵抗率）
　実施例および比較例で作製した半導体加工用保護シートを１０ｃｍ×１０ｃｍのサイズにカットし、半導体加工用保護シートの粘着剤層に紫外線を照射して硬化させた。硬化後の粘着剤層に対して、ＪＩＳ　Ｋ　７１９４に準拠して、２３℃５０％ＲＨ、印加電圧１００Ｖの条件で、アドバンテスト製表面抵抗率計Ｒ８２５２により表面抵抗率を測定した。 (Surface resistivity of adhesive layer after energy ray curing)
The protective sheets for semiconductor processing prepared in Examples and Comparative Examples were cut into a size of 10 cm×10 cm, and the pressure-sensitive adhesive layer of the protective sheet for semiconductor processing was irradiated with ultraviolet rays to be cured. The surface resistivity of the adhesive layer after curing was measured according to JIS K 7194 under the conditions of 23° C., 50% RH, and an applied voltage of 100 V using a surface resistivity meter R8252 manufactured by Advantest.
　（エネルギー線硬化前後の粘着剤層の９０°引き剥がし粘着力）
　実施例および比較例で作製した半導体加工用保護シートを２５ｍｍ幅にカットして試験片とした。質量２ｋｇのローラで試験片の粘着剤層を回路面が形成されていないシリコンミラーウエハに貼付した。１時間放置した後、ＪＩＳ　Ｚ　０２３７に準拠して、シリコンミラーウエハに対して９０°となるように剥離速度６００ｍｍ／分で試験片を引き剥がして粘着力（エネルギー線硬化前の粘着剤層の９０°引き剥がし粘着力）を測定した。 (90° peeling adhesive strength of adhesive layer before and after energy ray curing)
The protective sheets for semiconductor processing produced in Examples and Comparative Examples were cut to a width of 25 mm to obtain test pieces. The pressure-sensitive adhesive layer of the test piece was applied to a silicon mirror wafer having no circuit surface formed thereon with a roller having a mass of 2 kg. After leaving it for 1 hour, the test piece was peeled off at a peeling speed of 600 mm / min so that it was 90° to the silicon mirror wafer in accordance with JIS Z 0237, and the adhesive strength (the pressure-sensitive adhesive layer before curing with the energy beam 90° peel adhesion) was measured.
　また、別の試験片の粘着剤層を質量２ｋｇのローラでシリコンミラーウエハに貼付した。この試験片の粘着剤層に対して、半導体加工用保護シートの基材面側から紫外線を照度２２０ｍＷ／ｃｍ２、光量３８０ｍＪ／ｃｍ２の条件で照射して粘着剤層を硬化させた後、ＪＩＳ　Ｚ　０２３７に準拠して、シリコンミラーウエハに対して９０°となるように剥離速度６００ｍｍ／分で試験片を引き剥がして粘着力（エネルギー線硬化後の粘着剤層の９０°引き剥がし粘着力）を測定した。 Also, the pressure-sensitive adhesive layer of another test piece was attached to the silicon mirror wafer with a roller having a mass of 2 kg. The pressure-sensitive adhesive layer of this test piece was irradiated with ultraviolet rays from the substrate side of the protective sheet for semiconductor processing under the conditions of an illuminance of 220 mW/cm 2 and a light amount of 380 mJ/cm 2 to cure the pressure-sensitive adhesive layer. In accordance with JIS Z 0237, the test piece was peeled off at a peeling speed of 600 mm / min so that it was 90 ° to the silicon mirror wafer, and the adhesive strength (90 ° peeling adhesive strength of the adhesive layer after energy ray curing ) was measured.
　（半導体加工用保護シートの剥離帯電圧）
　実施例および比較例で作製した半導体加工用保護シートをシリコンウエハ表面に貼付して、ウエハマウンター（製品名「ＲＡＤ－２７００Ｆ／１２」、リンテック社製）を用いて、剥離速度６００ｍｍ／分、温度４０℃の条件で半導体加工用保護シートをシリコンウエハから剥離しながら、Ｐｒｏｓｔａｔ製剥離帯電測定器ＰＦＭ－７１１Ａを用いて、ウエハ表面および粘着剤層の剥離面側から１０ｍｍ離れた場所で電圧を測定し、ウエハ側の電圧値を剥離帯電圧値とした。本実施例では、剥離帯電圧が５００Ｖ以下である試料を良好であると判断した。 (Peeling electrification voltage of protective sheet for semiconductor processing)
The protective sheet for semiconductor processing prepared in Examples and Comparative Examples was attached to the surface of a silicon wafer, and a wafer mounter (product name “RAD-2700F/12”, manufactured by Lintec) was used to peel off at a rate of 600 mm / min and at a temperature of While peeling the protective sheet for semiconductor processing from the silicon wafer at 40° C., the voltage is measured at a place 10 mm away from the wafer surface and the peeling surface side of the adhesive layer using a Prostat peeling electrification meter PFM-711A. Then, the voltage value on the wafer side was taken as the peeling electrification voltage value. In this example, samples with a peeling electrification voltage of 500 V or less were judged to be good.
　（クラック発生率）
　直径１２インチ、厚み７７５μｍのシリコンウエハに、実施例および比較例で作製した半導体加工用保護シートを、バックグラインド用テープラミネーター（リンテック社製、装置名「ＲＡＤ－３５１０Ｆ／１２」）を用いて貼付した。レーザーソー（ディスコ社製、装置名「ＤＦＬ７３６１」）を用い、ウエハに格子状の改質領域を形成した。なお、格子サイズは１０ｍｍ×１０ｍｍとした。 (Crack occurrence rate)
A silicon wafer with a diameter of 12 inches and a thickness of 775 μm is attached to a protective sheet for semiconductor processing prepared in Examples and Comparative Examples using a tape laminator for back grinding (manufactured by Lintec, device name “RAD-3510F/12”). bottom. Using a laser saw (manufactured by Disco, device name "DFL7361"), a grid-shaped modified region was formed on the wafer. Note that the grid size was 10 mm×10 mm.
　次いで、裏面研削装置（ディスコ社製、装置名「ＤＧＰ８７６１」）を用いて、厚さ３０μｍになるまで研削（ドライポリッシュを含む）を行い、ウエハを複数のチップに個片化した。 Next, using a back surface grinding machine (manufactured by Disco, machine name "DGP8761"), the wafer was ground (including dry polishing) to a thickness of 30 µm, and the wafer was singulated into a plurality of chips.
　研削工程後にエネルギー線（紫外線）照射を行い、半導体加工用保護シートの貼付面の反対面にダイシングテープ（リンテック社製、Ａｄｗｉｌｌ　Ｄ-１７５）を貼付後、半導体加工用保護シートを剥離した。その後、個片化されたチップをデジタル顕微鏡（製品名「ＶＨＸ－１０００」、ＫＥＹＥＮＣＥ社製）で観察し、クラックの発生したチップを数え、クラックのサイズ毎に以下の基準で分類した。なお、クラックのサイズ（μｍ）は、チップの縦方向に沿ったクラックの長さ（μｍ）と、チップの横方向に沿ったクラックの長さ（μｍ）とを対比し、その数値の大きい方とした。
　（基準）
　大クラック：クラックのサイズが５０μｍ超
　中クラック：クラックのサイズが２０μｍ以上５０μｍ以下
　小クラック：クラックのサイズが２０μｍ未満 After the grinding step, energy rays (ultraviolet rays) were irradiated, and a dicing tape (Adwill D-175, manufactured by Lintec Corporation) was attached to the opposite side of the protective sheet for semiconductor processing, and then the protective sheet for semiconductor processing was peeled off. After that, the individualized chips were observed with a digital microscope (product name "VHX-1000", manufactured by KEYENCE), and the chips with cracks were counted and classified according to the size of the cracks according to the following criteria. Note that the crack size (μm) is obtained by comparing the crack length (μm) along the vertical direction of the chip and the crack length (μm) along the horizontal direction of the chip, and the larger of the values. and
(standard)
Large crack: Crack size greater than 50 μm Medium crack: Crack size 20 μm or more and 50 μm or less Small crack: Crack size less than 20 μm
　また、以下の式に基づき、クラック発生率（％）を算出した。クラック発生率が２．０％以下であり、大クラックの個数が０個、中クラックの個数が１０個以下、小クラックの個数が２０個以下の場合を「良好」、それ以外の場合を「不良」と評価した。
　クラック発生率(％)＝（クラックが発生したチップ数／全チップ数）×１００ Also, the crack generation rate (%) was calculated based on the following formula. If the crack generation rate is 2.0% or less, the number of large cracks is 0, the number of medium cracks is 10 or less, and the number of small cracks is 20 or less, it is "good". Poor”.
Crack occurrence rate (%) = (number of cracked chips/total number of chips) x 100
　（実施例１）
　（１）粘着剤層
　（粘着剤層用組成物の調製）
　ブチルアクリレート（ＢＡ）６５質量部、メチルメタクリレート（ＭＭＡ）２０質量部、及び２－ヒドロキシエチルアクリレート（２ＨＥＡ）１５質量部を共重合して得たアクリル系重合体に、アクリル系重合体の全水酸基のうち８０モル％の水酸基に付加するように、２－メタクリロイルオキシエチルイソシアネート（ＭＯＩ）を反応させて、エネルギー線硬化性のアクリル系樹脂（Ｍｗ：５０万）を得た。このエネルギー線硬化性のアクリル系樹脂１００質量部に、エネルギー線硬化性化合物である多官能ウレタンアクリレート（商品名：紫光ＵＴ－４３３２、三菱ケミカル株式会社製）６重量部、イソシアネート系架橋剤（東ソー株式会社製、商品名：コロネートＬ）を固形分基準で０．３７５質量部、ビス（２，４，６－トリメチルベンゾイル）フェニルフォスフィンオキシドからなる光重合開始剤１重量部を添加し、溶剤で希釈することにより粘着剤層用組成物の塗工液を調製した。 (Example 1)
(1) Adhesive layer (Preparation of composition for adhesive layer)
An acrylic polymer obtained by copolymerizing 65 parts by mass of butyl acrylate (BA), 20 parts by mass of methyl methacrylate (MMA), and 15 parts by mass of 2-hydroxyethyl acrylate (2HEA) is added with all hydroxyl groups of the acrylic polymer. 2-Methacryloyloxyethyl isocyanate (MOI) was reacted so as to be added to hydroxyl groups of 80 mol % of them to obtain an energy ray-curable acrylic resin (Mw: 500,000). To 100 parts by mass of this energy ray-curable acrylic resin, 6 parts by weight of polyfunctional urethane acrylate (trade name: Shikou UT-4332, manufactured by Mitsubishi Chemical Corporation), which is an energy ray-curable compound, an isocyanate-based cross-linking agent (Tosoh Co., Ltd., trade name: Coronate L) was added to 0.375 parts by weight based on the solid content, and 1 part by weight of a photopolymerization initiator made of bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide was added, and the solvent was to prepare a coating solution of the pressure-sensitive adhesive layer composition.
　（粘着剤層の形成）
　剥離シート（リンテック社製、商品名「ＳＰ－ＰＥＴ３８１０３１」、シリコーン剥離処理を行ったポリエチレンテレフタレート（ＰＥＴ）フィルム、厚さ：３８μｍ）の剥離処理がされた面上に、上記の粘着剤組成物の溶液を塗布し、乾燥させて、厚さ２０μｍの粘着剤層を有する、粘着剤層付き剥離シートを作製した。 (Formation of adhesive layer)
Release sheet (manufactured by Lintec, trade name “SP-PET381031”, polyethylene terephthalate (PET) film subjected to silicone release treatment, thickness: 38 μm). The solution was applied and dried to prepare a release sheet with an adhesive layer having an adhesive layer with a thickness of 20 μm.
　（２）帯電防止層付き基材の作製
　基材として、一方の面にプライマー層（第１のプライマー層）が設けられた厚さ５０μｍのプライマー付ＰＥＴフィルム（東洋紡社製、商品名「ＰＥＴ５０Ａ－４１００」）を準備した。このＰＥＴフィルムのヤング率は２５００ＭＰａであった。 (2) Preparation of substrate with antistatic layer As a substrate, a 50 μm thick primer-attached PET film (manufactured by Toyobo Co., Ltd., product name “PET50A- 4100”) were prepared. The Young's modulus of this PET film was 2500 MPa.
　ＰＥＴフィルムの第１のプライマー層が設けられているのとは反対側の面上に、ポリチオフェン系導電性ポリマー（ナガセケムテック株式会社製、デナトロンＰ－４００ＭＰ）を塗布し乾燥させて、厚さ１２０ｎｍの帯電防止層をＰＥＴフィルム上に形成した。 A polythiophene-based conductive polymer (Denatron P-400MP, manufactured by Nagase Chemtech Co., Ltd.) is applied to the surface of the PET film opposite to the surface on which the first primer layer is provided, and dried to obtain a thickness. A 120 nm antistatic layer was formed on the PET film.
　（３）緩衝層
　（ウレタンアクリレート系オリゴマー（ＵＡ－１）の合成）
　ポリエステルジオールと、イソホロンジイソシアネートを反応させて得られた末端イソシアネートウレタンプレポリマーに、２－ヒドロキシエチルアクリレートを反応させて、重量平均分子量（Ｍｗ）５０００の２官能のウレタンアクリレート系オリゴマー（ＵＡ－１）を得た。 (3) Buffer layer (synthesis of urethane acrylate oligomer (UA-1))
A terminal isocyanate urethane prepolymer obtained by reacting a polyester diol and isophorone diisocyanate is reacted with 2-hydroxyethyl acrylate to obtain a bifunctional urethane acrylate oligomer (UA-1) having a weight average molecular weight (Mw) of 5000. got
　（緩衝層形成用組成物の調製）
　エネルギー線重合性化合物として、製造例１で合成したウレタンアクリレート系オリゴマー（ＵＡ－１）４０質量部、イソボルニルアクリレート（ＩＢＸＡ）４０質量部、及びフェニルヒドロキシプロピルアクリレート（ＨＰＰＡ）２０質量部を配合し、さらに光重合開始剤としての１－ヒドロキシシクロヘキシルフェニルケトン（ＩＧＭ　Ｒｅｓｉｎｓ社製、製品名「ＯＭＮＩＲＡＤ１８４」）２．０質量部、及びフタロシアニン系顔料０．２質量部を配合し、緩衝層形成用組成物を調製した。 (Preparation of composition for forming buffer layer)
As energy ray-polymerizable compounds, 40 parts by mass of urethane acrylate oligomer (UA-1) synthesized in Production Example 1, 40 parts by mass of isobornyl acrylate (IBXA), and 20 parts by mass of phenylhydroxypropyl acrylate (HPPA) are blended. Then, 2.0 parts by mass of 1-hydroxycyclohexylphenyl ketone (manufactured by IGM Resins, product name “OMNIRAD184”) as a photopolymerization initiator and 0.2 parts by mass of a phthalocyanine pigment are blended to form a buffer layer. A composition was prepared.
　（緩衝層の形成）
　剥離シート（リンテック社製、商品名「ＳＰ－ＰＥＴ３８１０３１」、シリコーン剥離処理を行ったポリエチレンテレフタレート（ＰＥＴ）フィルム、厚さ：３８μｍ）の剥離処理がされた面上に、上記の緩衝層形成用組成物を塗布し塗布膜を形成した。そして、当該塗布膜に対して、紫外線を照射して、当該塗布膜を半硬化させ、厚さ５０μｍの緩衝層形成膜を形成した。 (Formation of buffer layer)
Release sheet (manufactured by Lintec, trade name “SP-PET381031”, polyethylene terephthalate (PET) film subjected to silicone release treatment, thickness: 38 μm). A material was applied to form a coating film. Then, the coating film was irradiated with ultraviolet rays to semi-harden the coating film, thereby forming a buffer layer forming film having a thickness of 50 μm.
　なお、上記の紫外線照射は、ベルトコンベア式紫外線照射装置（製品名「ＥＣＳ－４０１ＧＸ」、アイグラフィクス社製）及び高圧水銀ランプ（Ｈ０４－Ｌ４１アイグラフィクス社製：Ｈ０４－Ｌ４１）を使用し、ランプ高さ１５０ｍｍ、ランプ出力３ｋＷ（換算出力１２０ｍＷ／ｃｍ）、光線波長３６５ｎｍの照度１２０ｍＷ／ｃｍ２、照射量１００ｍＪ／ｃｍ２の照射条件下にて行った。 The above ultraviolet irradiation is performed using a belt conveyor type ultraviolet irradiation device (product name "ECS-401GX", manufactured by Eyegraphics) and a high-pressure mercury lamp (H04-L41 manufactured by Eyegraphics: H04-L41). The measurement was performed under irradiation conditions of a height of 150 mm, a lamp output of 3 kW (converted output of 120 mW/cm), an illuminance of 120 mW/cm 2 at a light wavelength of 365 nm, and a dose of 100 mJ/cm 2 .
　形成した緩衝層形成膜の表面と、帯電防止層付き基材の第１のプライマー層とを貼り合わせ、緩衝層形成膜上の剥離シート側から再度紫外線を照射して、当該緩衝層形成膜を完全に硬化させ、厚さ５０μｍの緩衝層を形成した。 The surface of the formed buffer layer-forming film and the first primer layer of the base material with an antistatic layer are laminated together, and ultraviolet rays are again irradiated from the release sheet side on the buffer layer-forming film to remove the buffer layer-forming film. It was completely cured to form a buffer layer with a thickness of 50 μm.
　なお、上記の紫外線照射は、上述の紫外線照射装置及び高圧水銀ランプを使用し、ランプ高さ１５０ｍｍ、ランプ出力３ｋＷ（換算出力１２０ｍＷ／ｃｍ）、光線波長３６５ｎｍの照度１６０ｍＷ／ｃｍ２、照射量５００ｍＪ／ｃｍ２の照射条件下にて行った。 The above ultraviolet irradiation uses the above-described ultraviolet irradiation device and high-pressure mercury lamp, with a lamp height of 150 mm, a lamp output of 3 kW (converted output of 120 mW/cm), an illuminance of 160 mW/cm 2 at a light wavelength of 365 nm, and an irradiation amount of 500 mJ. / cm 2 irradiation conditions.
　（４）半導体加工用保護シートの作製
　帯電防止層上に、粘着剤層付き剥離シートの粘着剤層を貼り合わせることで、基材の一方の主面上に帯電防止層および粘着剤層がこの順で形成され、基材の他方の主面上に緩衝層が形成されている半導体加工用保護シートを作製した。 (4) Preparation of protective sheet for semiconductor processing By laminating the adhesive layer of the release sheet with adhesive layer on the antistatic layer, the antistatic layer and the adhesive layer are formed on one main surface of the substrate. A protective sheet for semiconductor processing was produced, which was formed in order and had a buffer layer formed on the other main surface of the base material.
　（実施例２）
　帯電防止層の厚みを１５０ｎｍとし、粘着剤層の厚みを５μｍとした以外は実施例１と同じ方法により半導体加工用保護シートを得た。 (Example 2)
A protective sheet for semiconductor processing was obtained in the same manner as in Example 1, except that the thickness of the antistatic layer was 150 nm and the thickness of the adhesive layer was 5 μm.
　（実施例３）
　帯電防止層厚みを８０ｎｍとし、粘着剤層厚みを２００μｍとした以外は実施例１と同じ方法により半導体加工用保護シートを得た。 (Example 3)
A protective sheet for semiconductor processing was obtained in the same manner as in Example 1, except that the thickness of the antistatic layer was 80 nm and the thickness of the adhesive layer was 200 μm.
　（実施例４）
　以下の粘着剤層用組成物を用いて粘着剤層を形成した以外は実施例１と同じ方法により半導体加工用保護シートを得た。 (Example 4)
A protective sheet for semiconductor processing was obtained in the same manner as in Example 1, except that the following adhesive layer composition was used to form the adhesive layer.
　（粘着剤層用組成物の調製）
　ｎ－ブチルアクリレート（ＢＡ）８９質量部、メチルメタクリレート（ＭＭＡ）８質量部、及び２－ヒドロキシエチルアクリレート（２ＨＥＡ）３質量部を共重合してアクリル系重合体（Ｍｗ：８０万）を得た。 (Preparation of composition for adhesive layer)
An acrylic polymer (Mw: 800,000) was obtained by copolymerizing 89 parts by mass of n-butyl acrylate (BA), 8 parts by mass of methyl methacrylate (MMA), and 3 parts by mass of 2-hydroxyethyl acrylate (2HEA). .
　上述のアクリル系重合体１００質量部に対し、架橋剤としてトリレンジイソシアネート系架橋剤（東ソー社製、製品名「コロネートＬ」）１質量部（固形分）、エポキシ系架橋剤（１,３-ビス（Ｎ,Ｎ-ジグリシジルアミノメチル）シクロヘキサン）２質量部（固形分）と、エネルギー線硬化性化合物（三菱ケミカル株式会社製、製品名「紫光ＵＶ－３２１０ＥＡ」）４５質量部（固形分）と光重合開始剤（ＩＧＭ　Ｒｅｓｉｎｓ社製、製品名「ＯＭＮＩＲＡＤ１８４」）１質量部（固形分）を混合し、溶剤で希釈することにより粘着剤層用組成物の塗工液を得た。 For 100 parts by mass of the acrylic polymer described above, 1 part by mass (solid content) of a tolylene diisocyanate-based cross-linking agent (manufactured by Tosoh Corporation, product name "Coronate L") as a cross-linking agent, an epoxy-based cross-linking agent (1,3- Bis(N,N-diglycidylaminomethyl)cyclohexane) 2 parts by mass (solid content) and an energy ray-curable compound (manufactured by Mitsubishi Chemical Corporation, product name “Shikou UV-3210EA”) 45 parts by mass (solid content) and 1 part by mass (solid content) of a photopolymerization initiator (manufactured by IGM Resins, product name "OMNIRAD 184"), and diluted with a solvent to obtain a coating liquid for a composition for an adhesive layer.
　（実施例５）
　以下の粘着剤層用組成物を用いて粘着剤層を形成し、帯電防止層の厚みを２５ｎｍ、粘着剤層の厚みを５μｍとした以外は、実施例１と同じ方法により半導体加工用保護シートを得た。 (Example 5)
A protective sheet for semiconductor processing was prepared in the same manner as in Example 1, except that a pressure-sensitive adhesive layer was formed using the following pressure-sensitive adhesive layer composition, and the thickness of the antistatic layer was 25 nm and the thickness of the pressure-sensitive adhesive layer was 5 μm. got
　（粘着剤層用組成物の調製）
　ブチルアクリレート（ＢＡ）７５質量部、メチルメタクリレート（ＭＭＡ）２０質量部、及び２－ヒドロキシエチルアクリレート（２ＨＥＡ）５質量部を共重合して得たアクリル系重合体に、アクリル系重合体の全水酸基のうち９０モル％の水酸基に付加するように、２－メタクリロイルオキシエチルイソシアネート（ＭＯＩ）を反応させて、エネルギー線硬化性のアクリル系樹脂（Ｍｗ：５０万）を得た。 (Preparation of composition for adhesive layer)
An acrylic polymer obtained by copolymerizing 75 parts by mass of butyl acrylate (BA), 20 parts by mass of methyl methacrylate (MMA), and 5 parts by mass of 2-hydroxyethyl acrylate (2HEA) is added with all hydroxyl groups of the acrylic polymer. 2-Methacryloyloxyethyl isocyanate (MOI) was reacted so as to be added to hydroxyl groups of 90 mol % of them to obtain an energy ray-curable acrylic resin (Mw: 500,000).
　このエネルギー線硬化性のアクリル系樹脂１００質量部に、イソシアネート系架橋剤（東ソー株式会社製、商品名：コロネートＬ）を固形分基準で０．３７５質量部、ビス（２，４，６－トリメチルベンゾイル）フェニルフォスフィンオキシドからなる光重合開始剤１重量部を添加し、溶剤で希釈することにより粘着剤層用組成物の塗工液を調製した。 To 100 parts by mass of this energy ray-curable acrylic resin, 0.375 parts by mass of an isocyanate cross-linking agent (manufactured by Tosoh Corporation, trade name: Coronate L) based on solid content, bis(2,4,6-trimethyl 1 part by weight of a photopolymerization initiator consisting of benzoyl)phenylphosphine oxide was added, and the mixture was diluted with a solvent to prepare a coating liquid for a pressure-sensitive adhesive layer composition.
　（比較例１）
　帯電防止層を設けなかった以外は実施例１と同じ方法により半導体加工用保護シートを得た。 (Comparative example 1)
A protective sheet for semiconductor processing was obtained in the same manner as in Example 1, except that no antistatic layer was provided.
　（比較例２）
　以下の粘着剤層用組成物を用いて粘着剤層を形成し、帯電防止層の厚みを５０ｎｍとした以外は、実施例１と同じ方法により半導体加工用保護シートを得た。 (Comparative example 2)
A protective sheet for semiconductor processing was obtained in the same manner as in Example 1, except that a pressure-sensitive adhesive layer was formed using the following pressure-sensitive adhesive layer composition and the thickness of the antistatic layer was changed to 50 nm.
　（粘着剤層用組成物の調製）
　ブチルアクリレート（ＢＡ）６５質量部、メチルメタクリレート（ＭＭＡ）２０質量部、及び２－ヒドロキシエチルアクリレート（２ＨＥＡ）１５質量部を共重合して得たアクリル系重合体に、アクリル系重合体の全水酸基のうち９０モル％の水酸基に付加するように、２－メタクリロイルオキシエチルイソシアネート（ＭＯＩ）を反応させて、エネルギー線硬化性のアクリル系樹脂（Ｍｗ：５０万）を得た。 (Preparation of composition for adhesive layer)
An acrylic polymer obtained by copolymerizing 65 parts by mass of butyl acrylate (BA), 20 parts by mass of methyl methacrylate (MMA), and 15 parts by mass of 2-hydroxyethyl acrylate (2HEA) is added with all hydroxyl groups of the acrylic polymer. 2-Methacryloyloxyethyl isocyanate (MOI) was reacted so as to be added to hydroxyl groups of 90 mol % of them to obtain an energy ray-curable acrylic resin (Mw: 500,000).
　このエネルギー線硬化性のアクリル系樹脂１００質量部に、エネルギー線硬化性化合物である多官能ウレタンアクリレート（商品名：紫光ＵＴ－４３３２、三菱ケミカル株式会社製）２０重量部、イソシアネート系架橋剤（東ソー株式会社製、商品名：コロネートＬ）を固形分基準で０．３７５質量部、ビス（２，４，６－トリメチルベンゾイル）フェニルフォスフィンオキシドからなる光重合開始剤１重量部を添加し、溶剤で希釈することにより粘着剤層用組成物の塗工液を調製した。 To 100 parts by mass of this energy ray-curable acrylic resin, 20 parts by weight of polyfunctional urethane acrylate (trade name: Shikou UT-4332, manufactured by Mitsubishi Chemical Corporation), which is an energy ray-curable compound, an isocyanate-based cross-linking agent (Tosoh Co., Ltd., trade name: Coronate L) was added to 0.375 parts by weight based on the solid content, and 1 part by weight of a photopolymerization initiator made of bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide was added, and the solvent was to prepare a coating solution of the pressure-sensitive adhesive layer composition.
　（比較例３）
　以下の粘着剤層用組成物を用いて粘着剤層を形成した以外は、実施例１と同じ方法により半導体加工用保護シートを得た。 (Comparative Example 3)
A protective sheet for semiconductor processing was obtained in the same manner as in Example 1, except that the following adhesive layer composition was used to form the adhesive layer.
　（粘着剤層用組成物の調製）
　ブチルアクリレート（ＢＡ）７５質量部、メチルメタクリレート（ＭＭＡ）２０質量部、及び２－ヒドロキシエチルアクリレート（２ＨＥＡ）５質量部を共重合して得たアクリル系重合体に、アクリル系重合体の全水酸基のうち５０モル％の水酸基に付加するように、２－メタクリロイルオキシエチルイソシアネート（ＭＯＩ）を反応させて、エネルギー線硬化性のアクリル系樹脂（Ｍｗ：５０万）を得た。 (Preparation of composition for adhesive layer)
An acrylic polymer obtained by copolymerizing 75 parts by mass of butyl acrylate (BA), 20 parts by mass of methyl methacrylate (MMA), and 5 parts by mass of 2-hydroxyethyl acrylate (2HEA) is added with all hydroxyl groups of the acrylic polymer. 2-Methacryloyloxyethyl isocyanate (MOI) was reacted so as to be added to hydroxyl groups of 50 mol % of them to obtain an energy ray-curable acrylic resin (Mw: 500,000).
　このエネルギー線硬化性のアクリル系樹脂１００質量部に、イソシアネート系架橋剤（東ソー株式会社製、商品名：コロネートＬ）を固形分基準で０．３７５質量部、ビス（２，４，６－トリメチルベンゾイル）フェニルフォスフィンオキシドからなる光重合開始剤１重量部を添加し、溶剤で希釈することにより粘着剤層用組成物の塗工液を調製した。 To 100 parts by mass of this energy ray-curable acrylic resin, 0.375 parts by mass of an isocyanate cross-linking agent (manufactured by Tosoh Corporation, trade name: Coronate L) based on solid content, bis(2,4,6-trimethyl 1 part by weight of a photopolymerization initiator consisting of benzoyl)phenylphosphine oxide was added, and the mixture was diluted with a solvent to prepare a coating liquid for a pressure-sensitive adhesive layer composition.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　得られた試料（実施例１～５および比較例１～３）に対して、上記の測定および評価を行った。粘着力比は、エネルギー線硬化前後の粘着剤層の９０°引き剥がし粘着力から算出した。結果を表１に示す。 The above measurements and evaluations were performed on the obtained samples (Examples 1 to 5 and Comparative Examples 1 to 3). The adhesive force ratio was calculated from the 90° peeling adhesive force of the adhesive layer before and after energy ray curing. Table 1 shows the results.
　表１より、半導体加工用保護シートの粘着剤層の表面抵抗率が上述した範囲内であり、かつ半導体加工用保護シートに帯電防止層が含まれている場合には、半導体加工用保護シートの剥離に伴う帯電圧が低く、さらにチップシフトに起因するクラック発生率が低いことが確認できた。 From Table 1, when the surface resistivity of the adhesive layer of the protective sheet for semiconductor processing is within the range described above and the protective sheet for semiconductor processing includes an antistatic layer, the protective sheet for semiconductor processing It was confirmed that the electrification voltage associated with delamination was low and the crack generation rate due to chip shift was low.
１…半導体加工用保護シート
　１０…基材
　２０…帯電防止層
　３０…粘着剤層
　４０…緩衝層 DESCRIPTION OF SYMBOLS 1... Protection sheet for semiconductor processing 10... Base material 20... Antistatic layer 30... Adhesive layer 40... Buffer layer

Claims (7)

  1. 　基材と、帯電防止層と、エネルギー線硬化性の粘着剤層と、緩衝層と、を有し、
    　エネルギー線硬化後の粘着剤層の表面抵抗率が５．１×１０１２Ω／ｃｍ２以上１．０×１０１５Ω／ｃｍ２以下である半導体加工用保護シート。     having a substrate, an antistatic layer, an energy ray-curable adhesive layer, and a buffer layer,
    A protective sheet for semiconductor processing, wherein the surface resistivity of the pressure-sensitive adhesive layer after energy ray curing is 5.1×10 12 Ω/cm 2 or more and 1.0×10 15 Ω/cm 2 or less.
  2. 　エネルギー線硬化後の粘着剤層をシリコンウエハから剥離速度６００ｍｍ／分で前記粘着剤層と前記シリコンウエハとのなす角度が９０°となるように引き剥がした時の粘着力が０．１５Ｎ／２５ｍｍ未満である請求項１に記載の半導体加工用保護シート。 The adhesive layer after energy beam curing was peeled off from the silicon wafer at a peeling speed of 600 mm/min so that the angle formed by the adhesive layer and the silicon wafer was 90°, and the adhesive strength was 0.15 N/25 mm. 2. The protective sheet for semiconductor processing according to claim 1, wherein the thickness is less than.
  3. 　エネルギー線硬化前の粘着剤層をシリコンウエハから剥離速度６００ｍｍ／分で前記粘着剤層と前記シリコンウエハとのなす角度が９０°となるように引き剥がした時の粘着力に対して、エネルギー線硬化後の粘着剤層をシリコンウエハから剥離速度６００ｍｍ／分で前記粘着剤層と前記シリコンウエハとのなす角度が９０°となるように引き剥がした時の粘着力の比が、４％以下である請求項１または２に記載の半導体加工用保護シート。 The adhesive force when the adhesive layer before energy ray curing is peeled off from the silicon wafer at a peeling speed of 600 mm / min so that the angle formed by the adhesive layer and the silicon wafer is 90 °. The adhesive force ratio when the adhesive layer after curing is peeled off from the silicon wafer at a peeling speed of 600 mm/min so that the angle formed by the adhesive layer and the silicon wafer is 90° is 4% or less. 3. The protective sheet for semiconductor processing according to claim 1 or 2.
  4. 　前記基材のヤング率が１０００ＭＰａ以上である請求項１から３のいずれかに記載の半導体加工用保護シート。 The protective sheet for semiconductor processing according to any one of claims 1 to 3, wherein the base material has a Young's modulus of 1000 MPa or more.
  5. 　前記半導体加工用保護シートは、前記基材の一方の主面上に前記粘着剤層を有し、前記基材と前記粘着剤層との間に前記帯電防止層が設けられ、前記基材の他方の主面上に前記緩衝層が設けられている構成、または、前記基材の一方の主面上に前記粘着剤層を有し、前記基材と前記粘着剤層との間に前記帯電防止層および前記緩衝層が設けられている構成を有する請求項１から４のいずれかに記載の半導体加工用保護シート。 The protective sheet for semiconductor processing has the pressure-sensitive adhesive layer on one main surface of the base material, the antistatic layer is provided between the base material and the pressure-sensitive adhesive layer, and A configuration in which the buffer layer is provided on the other main surface, or a structure in which the adhesive layer is provided on one main surface of the base material, and the electrification is provided between the base material and the adhesive layer 5. The protective sheet for semiconductor processing according to any one of claims 1 to 4, wherein the protection layer and the buffer layer are provided.
  6. 　表面に溝、または、内部に改質領域が形成されたウエハの裏面を研削することによりウエハをチップに個片化する工程において、ウエハの表面に貼付されて使用される請求項１から５のいずれかに記載の半導体加工用保護シート。 It is attached to the surface of the wafer and used in the step of singulating the wafer into chips by grinding the back surface of the wafer having grooves on the surface or a modified region formed therein. The protective sheet for semiconductor processing according to any one of the above.
  7. 　請求項１から６のいずれかに記載の半導体加工用保護シートを、ウエハの表面に貼付する工程と、
    　前記ウエハの表面側から溝を形成する工程、または、前記ウエハの表面もしくは裏面から前記ウエハ内部に改質領域を形成する工程と、
    　前記半導体加工用保護シートが表面に貼付され、かつ前記溝または前記改質領域が形成されたウエハを、裏面側から研削して、前記溝または前記改質領域を起点として、複数のチップに個片化させる工程と、
    　個片化されたチップから、前記半導体加工用保護シートを剥離する工程と、を有する半導体装置の製造方法。     a step of attaching the protective sheet for semiconductor processing according to any one of claims 1 to 6 to the surface of a wafer;
    a step of forming a groove from the front surface side of the wafer, or a step of forming a modified region inside the wafer from the front surface or the rear surface of the wafer;
    A wafer having the protective sheet for semiconductor processing attached to the front surface and having the grooves or the modified regions formed therein is ground from the rear surface side, and a plurality of chips are individually separated from the grooves or the modified regions starting from the grooves or the modified regions. a step of separating;
    and peeling off the protective sheet for semiconductor processing from the individualized chips.
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