CN115873525A - Adhesive sheet for semiconductor processing and method for manufacturing semiconductor device - Google Patents

Adhesive sheet for semiconductor processing and method for manufacturing semiconductor device Download PDF

Info

Publication number
CN115873525A
CN115873525A CN202211184038.XA CN202211184038A CN115873525A CN 115873525 A CN115873525 A CN 115873525A CN 202211184038 A CN202211184038 A CN 202211184038A CN 115873525 A CN115873525 A CN 115873525A
Authority
CN
China
Prior art keywords
adhesive sheet
layer
meth
mass
surface coating
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
CN202211184038.XA
Other languages
Chinese (zh)
Inventor
梅泽昌弘
坂东沙也香
田村和幸
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Lintec Corp
Original Assignee
Lintec Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Lintec Corp filed Critical Lintec Corp
Publication of CN115873525A publication Critical patent/CN115873525A/en
Pending legal-status Critical Current

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J7/00—Adhesives in the form of films or foils
    • C09J7/20—Adhesives in the form of films or foils characterised by their carriers
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L83/00—Compositions of macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon only; Compositions of derivatives of such polymers
    • C08L83/04—Polysiloxanes
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D175/00—Coating compositions based on polyureas or polyurethanes; Coating compositions based on derivatives of such polymers
    • C09D175/04—Polyurethanes
    • 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 potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
    • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table 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
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2221/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof covered by H01L21/00
    • H01L2221/67—Apparatus for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components; Apparatus not specifically provided for elsewhere
    • H01L2221/683—Apparatus for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components; Apparatus not specifically provided for elsewhere for supporting or gripping
    • H01L2221/68304—Apparatus for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components; Apparatus not specifically provided for elsewhere for supporting or gripping using temporarily an auxiliary support
    • H01L2221/68327—Apparatus for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components; Apparatus not specifically provided for elsewhere for supporting or gripping using temporarily an auxiliary support used during dicing or grinding

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Organic Chemistry (AREA)
  • Power Engineering (AREA)
  • Computer Hardware Design (AREA)
  • Manufacturing & Machinery (AREA)
  • General Physics & Mathematics (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • Physics & Mathematics (AREA)
  • Wood Science & Technology (AREA)
  • Materials Engineering (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Polymers & Plastics (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Medicinal Chemistry (AREA)
  • Mechanical Treatment Of Semiconductor (AREA)
  • Adhesive Tapes (AREA)
  • Adhesives Or Adhesive Processes (AREA)
  • Dicing (AREA)

Abstract

The present invention relates to an adhesive sheet for semiconductor processing, which comprises a surface coating layer, a cushion layer, a base material, and an adhesive layer in this order, wherein the coefficient of static friction of the surface coating layer with respect to SUS304 is 0.70 or less, and a method for manufacturing a semiconductor device using the adhesive sheet for semiconductor processing.

Description

Adhesive sheet for semiconductor processing and method for manufacturing semiconductor device
Technical Field
The present invention relates to an adhesive sheet for semiconductor processing and a method for manufacturing a semiconductor device.
Background
In the rapid progress of thinning, miniaturization, and multi-functionalization of information terminal devices, thinning and densification are also required for semiconductor devices mounted on these devices.
As a method for thinning a semiconductor device, a method for grinding a back surface of a semiconductor wafer used for the semiconductor device is performed. In back grinding of a semiconductor wafer, an adhesive sheet for back grinding (hereinafter also referred to as "back lapping") is stuck to the front surface of the semiconductor wafer, and the front surface of the semiconductor wafer is protected by the sheet. The back grinding chip is peeled off from the surface of the semiconductor wafer after back grinding.
In recent years, as a grinding and singulation method for thinning while suppressing damage to a semiconductor chip, a tip dicing method, a stealth tip dicing method, or the like has been practically used. The tip cutting method is as follows: after a groove having a predetermined depth is formed on the front surface of a semiconductor wafer with a dicing blade or the like, the semiconductor wafer is ground from the back surface side to the groove, thereby dividing the semiconductor wafer into semiconductor chips. In addition, the stealth tip cutting method is as follows: after forming a modified region in a semiconductor wafer by laser irradiation, the semiconductor wafer is ground from the back side and is divided into semiconductor chips by using the modified region as a dividing starting point. In each of these methods, a back grinding chip for protecting the surface of a semiconductor wafer is used.
In addition to the development of these thinning process techniques, the back grinding sheet is also required to have a function for thinning a semiconductor chip with a high yield, and various studies have been made.
Patent document 1 discloses, as a pressure-sensitive adhesive sheet for protecting the surface of a semiconductor wafer applicable to a tip dicing method or a stealth tip dicing method, a pressure-sensitive adhesive sheet for protecting the surface of a semiconductor wafer, which comprises a base film, an intermediate layer provided on at least one surface side of the base film and formed of a pressure-sensitive adhesive, and an outermost pressure-sensitive adhesive layer provided on the outermost layer, which is the opposite side of the intermediate layer from the base film, wherein the intermediate layer is formed of a material that is cured by a curing treatment after the pressure-sensitive adhesive sheet is formed.
Documents of the prior art
Patent document
Patent document 1: japanese patent laid-open publication No. 2015-56446
Disclosure of Invention
Problems to be solved by the invention
According to the adhesive sheet for protecting the surface of a semiconductor wafer of patent document 1, it is possible to suppress the occurrence of chipping and chipping of the semiconductor wafer when the surface protective tape is peeled off, while suppressing the occurrence of chipping and chipping of the semiconductor wafer when the semiconductor wafer is singulated into chips.
On the other hand, in back grinding, a back grinding chip attached to a semiconductor wafer is fixed to a surface (hereinafter, also referred to as "back surface") opposite to the surface attached to the semiconductor wafer by a supporting device such as a chuck table. Then, the semiconductor wafer fixed on the table of the supporting device via the back grinding plate is ground on the back surface while supplying cooling water for removing heat and grinding chips generated by grinding to the grinding surface.
When back grinding is performed, if grinding chips are present between the back grinding plate and the table of the supporting device, cracks may be generated in the semiconductor wafer or the semiconductor chip starting from a portion where the grinding chips are present due to an impact when the semiconductor wafer is fixed to the table, pressurization and vibration in back grinding, and the like. Since the grinding chips adhere to the back surface of the back grinding piece in a state of being contained in the cooling water, it is necessary to reduce the amount of the grinding chips adhering to the back surface of the back grinding piece in order to suppress the occurrence of the above-described cracks.
In addition, when grinding a semiconductor wafer, although cooling water for removing frictional heat generated by grinding is supplied, it is difficult to completely remove the frictional heat, and the temperature of a back grinding piece holding the semiconductor wafer rises to some extent. That is, when grinding a semiconductor wafer, the back grinding chip is heated for a certain period of time in a state of being pressurized with respect to a supporting device such as a chuck table, and thus the back grinding chip may be excessively adhered to the supporting device. The semiconductor wafer after the grinding is lifted up from the supporting device by the carrying arm or the like and is carried for a subsequent process, but if the back grinding piece and the supporting device are excessively close together, the lifting-up failure may occur and the carrying may not be performed. This problem tends to be particularly pronounced when a back grinding sheet having a reduced amount of grinding dust adhering to the back surface is used.
The pressure-sensitive adhesive sheet for protecting the surface of a semiconductor wafer of patent document 1 is not sufficiently compatible with the requirements for reduction in the amount of adhesion of grinding chips to the back surface of the back grinding chip and improvement in the carrying property.
The present invention has been made in view of the above circumstances, and an object thereof is to provide an adhesive sheet for semiconductor processing that reduces the amount of adhesion of grinding chips and has excellent transportability, and a method for manufacturing a semiconductor device using the adhesive sheet for semiconductor processing.
Means for solving the problems
As a result of intensive studies, the present inventors have found that the above problems can be solved by a pressure-sensitive adhesive sheet for semiconductor processing, which comprises a surface coating layer having a static friction coefficient in a specific range, a cushion layer, a base material, and a pressure-sensitive adhesive layer in this order, and have completed the following invention.
That is, the present invention relates to the following [1] to [11].
[1] An adhesive sheet for semiconductor processing, which comprises a surface coating layer, a cushion layer, a substrate and an adhesive layer in this order,
the surface coating has a static friction coefficient of 0.70 or less with respect to SUS 304.
[2] The adhesive sheet for semiconductor processing according to the above [1], wherein,
the surface coating layer is a layer formed from a surface coating layer-forming composition containing a resin component and a slip property-improving component.
[3] The adhesive sheet for semiconductor processing according to the above [2], wherein,
the heteroatom content of the resin component is 7 mass% or less.
[4] The adhesive sheet for semiconductor processing according to the above [2] or [3], wherein,
the content of the resin component in the top coat layer-forming composition is 50 to 99% by mass based on the total amount (100% by mass) of the active components in the top coat layer-forming composition.
[5] The adhesive sheet for semiconductor processing according to any one of the above [2] to [4],
the sliding property improving component has a heteroatom content of 30 mass% or more.
[6] The adhesive sheet for semiconductor processing according to any one of the above [2] to [5],
the content of the sliding property improving component in the surface coating layer forming composition is 0.1 to 30% by mass relative to the total amount (100% by mass) of the active components in the surface coating layer forming composition.
[7] The adhesive sheet for semiconductor processing according to any one of the above [1] to [6],
the thickness of the surface coating is 0.05-10 μm.
[8] The adhesive sheet for semiconductor processing according to any one of the above [1] to [7],
the buffer layer is formed from a composition for forming a buffer layer containing urethane (meth) acrylate.
[9] The adhesive sheet for semiconductor processing according to any one of the above [1] to [8], which is used for back grinding of a semiconductor wafer.
[10] A method of manufacturing a semiconductor device, the method comprising:
a step of bonding the adhesive sheet for semiconductor processing according to any one of [1] to [9] to a surface of a semiconductor wafer with the adhesive layer as a bonding surface; and
and grinding the back surface of the semiconductor wafer while the adhesive sheet for semiconductor processing adhered to the semiconductor wafer is held on the surface coating layer side by a holding device.
[11] The method for manufacturing a semiconductor device according to [10], comprising:
a predetermined dividing line forming step a of forming a groove in a front surface of a semiconductor wafer or a step b of forming a modified region from the front surface or the back surface of the semiconductor wafer into the semiconductor wafer;
a sheet sticking step of sticking the adhesive sheet for semiconductor processing according to any one of [1] to [9] to the surface of the semiconductor wafer with the adhesive layer as a sticking surface after the step a, or before or after the step b; and
and a grinding and singulation step of grinding the back surface of the semiconductor wafer while the front surface coating side of the adhesive sheet for semiconductor processing attached to the semiconductor wafer is fixed by a support device, and singulating the adhesive sheet into a plurality of semiconductor chips with the grooves or the modified regions as starting points.
ADVANTAGEOUS EFFECTS OF INVENTION
According to the present invention, it is possible to provide an adhesive sheet for semiconductor processing having a reduced amount of grinding chips attached and excellent transportability, and a method for manufacturing a semiconductor device using the adhesive sheet for semiconductor processing.
Detailed Description
In the present specification, for a preferable numerical range, the lower limit value and the upper limit value described in steps may be independently combined. For example, according to the description of "preferably 10 to 90, more preferably 30 to 60", the "preferred lower limit value (10)" and the "more preferred upper limit value (60)" may be combined to obtain "10 to 60".
In the present specification, "(meth) acrylic" means both "acrylic" and "methacrylic", and other similar terms are used.
In the present specification, the "energy ray" refers to a ray having an energy quantum in an electromagnetic wave or a charged particle beam, and examples thereof include ultraviolet rays, radiation, an electron beam, and the like. The ultraviolet rays can be irradiated by using, for example, an electrodeless lamp, a high-pressure mercury lamp, a metal halide lamp, a UV-LED, or the like as an ultraviolet light source. The electron beam may irradiate an electron beam generated by an electron beam accelerator or the like.
In the present specification, the "energy ray polymerizability" refers to a property of causing polymerization by irradiation with an energy ray. The term "energy ray-curable property" refers to a property of curing by irradiation with an energy ray, and the term "non-energy ray-curable property" refers to a property of not having energy ray-curable properties.
In this specification, the "front surface" of the semiconductor wafer refers to a surface on which a circuit is formed, and the "back surface" refers to a surface on which no circuit is formed.
The mechanism of action described in the present specification is presumed, and is not limited to the mechanism of exerting the effect of the adhesive sheet for semiconductor processing of the present invention.
[ adhesive sheet for semiconductor processing ]
The adhesive sheet for semiconductor processing (hereinafter also referred to as "adhesive sheet") of the present embodiment includes a surface coating layer, a cushion layer, a base material, and an adhesive layer in this order, and the surface coating layer has a static friction coefficient of 0.70 or less with respect to SUS 304.
The adhesive sheet of the present embodiment is used for being stuck to a surface of a semiconductor device as a work and performing a predetermined process on the semiconductor device while protecting the surface. After a predetermined processing is performed on the workpiece, the adhesive sheet of the present embodiment is peeled and removed from the semiconductor device.
In this embodiment, the term "semiconductor device" refers to all devices that can function by utilizing semiconductor characteristics, and examples thereof include: a semiconductor wafer, a semiconductor chip, an electronic component including the semiconductor chip, an electronic device including the electronic component, and the like. Among them, the adhesive sheet of the present embodiment is suitable for processing of semiconductor wafers.
The pressure-sensitive adhesive sheet of the present embodiment may or may not have a layer other than the surface coating layer, the cushion layer, the substrate, and the pressure-sensitive adhesive layer. Examples of the layer other than the substrate and the pressure-sensitive adhesive layer include: an intermediate layer provided between the substrate and the pressure-sensitive adhesive layer, a release sheet provided on the surface of the pressure-sensitive adhesive layer opposite to the substrate, and the like.
Hereinafter, each member constituting the adhesive sheet of the present embodiment will be described in order.
< surface coating >
The surface coating layer is provided on the side of the buffer layer opposite to the base material, and is a layer fixed by the support device when the semiconductor device is processed.
(coefficient of static Friction)
The surface coating layer of the pressure-sensitive adhesive sheet of the present embodiment has a static friction coefficient of 0.70 or less with respect to SUS 304.
The adhesive sheet of the present embodiment has a coefficient of static friction of 0.70 or less with respect to SUS304 as the surface coating layer, and thus can reduce the amount of adhesion of grinding debris and has excellent transportability. The reason for this is not yet clear, but it is presumed that the surface coating having a static friction coefficient of 0.70 or less is less likely to adhere water containing grinding chips, and excessive adhesion to a support device or the like can be suppressed.
From the above-described viewpoint, the coefficient of static friction of the surface coating layer of the psa sheet of the present embodiment with respect to SUS304 is preferably 0.60 or less, and more preferably 0.50 or less.
On the other hand, the lower limit of the coefficient of static friction of the surface coating layer of the psa sheet of the present embodiment with respect to SUS304 is not particularly limited, but may be, for example, 0.01 or more, 0.10 or more, and 0.20 or more, from the viewpoint of ease of manufacturing and the like.
The static friction coefficient of the surface coating with respect to SUS304 is a value measured according to JIS K7125.
The surface coating layer of the pressure-sensitive adhesive sheet of the present embodiment is preferably formed of a surface coating layer-forming composition containing a resin component and a slip property-improving component.
(resin component)
The resin component is preferably a thermoplastic resin, and more preferably a polyolefin resin, from the viewpoint of reducing the amount of adhering grinding chips.
[ polyolefin resin ]
By adding the polyolefin resin to the surface coat layer-forming composition, the surface coat layer of the pressure-sensitive adhesive sheet of the present embodiment tends to further reduce the amount of adhesion of grinding chips.
The polyolefin-based resin is a resin obtained by polymerizing at least a monomer containing an olefin.
Here, the "polyolefin-based resin" in the present embodiment refers to any resin containing 50 mass% or more of a structural unit derived from an olefin, in a resin obtained by homopolymerizing an olefin or a resin obtained by copolymerizing an olefin and a monomer other than an olefin.
The term "olefin" in the present embodiment refers to an unsaturated hydrocarbon having an ethylenically unsaturated bond, and a compound containing a heteroatom is included in the "olefin" in the present embodiment. In the present specification, the term "heteroatom" refers to all atoms except carbon and hydrogen atoms.
In the following description, a group containing an ethylenically unsaturated bond may be simply referred to as an "unsaturated group".
The polyolefin-based resin may be used alone in 1 kind, or may be used in combination in 2 or more kinds.
The content of the olefin-derived structural unit in the polyolefin-based resin is not particularly limited, and is preferably 70% by mass or more, more preferably 90% by mass or more, and still more preferably 95% by mass or more. When the content of the olefin-derived structural unit in the polyolefin-based resin is not less than the lower limit value, the amount of adhesion of the grinding chips tends to be further reduced.
The content of the olefin-derived structural unit in the polyolefin-based resin may be 100% by mass, but may be 99.5% by mass or less, or may be 99% by mass or less, for example, in order to contain a structural unit derived from a monomer other than an olefin for the purpose of improving solvent solubility or the like.
Examples of the olefin constituting the polyolefin-based resin include: chain olefins, cyclic olefins, aromatic vinyl compounds, and the like.
The olefin constituting the polyolefin-based resin may be used alone in 1 kind, or may be used in combination in 2 or more kinds.
Examples of the chain olefin include: chain monoolefins such as ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 2-methyl-1-propene, 3-methyl-1-pentene, 4-methyl-1-pentene and 5-methyl-1-hexene; chain nonconjugated dienes such as 1, 4-hexadiene, 4-methyl-1, 4-hexadiene, and 5-methyl-1, 4-hexadiene; chain conjugated dienes such as 1, 3-butadiene, isoprene, 1, 3-pentadiene, 2, 3-dimethyl-1, 3-butadiene, 2-phenyl-1, 3-butadiene and 1, 3-hexadiene; and so on. Among them, linear olefins having 2 to 6 carbon atoms are preferable, and ethylene and propylene are more preferable.
Examples of the cyclic olefin include: cyclic monoolefins such as cyclobutene, cyclopentene, methylcyclopentene, cyclohexene, methylcyclohexene, cycloheptene, cyclooctene and the like; cyclic diolefins such as cyclohexadiene, methylcyclohexadiene, cyclooctadiene, methylcyclooctadiene and phenylcyclooctadiene; polycyclic olefins such as norbornene, dicyclopentadiene, tetracyclododecene, ethyltetracyclododecene, ethylidenetetracyclododecene, tetracyclo [7.4.0.110,13.02,7] tridec-2, 4,6, 11-tetraene, and the like; and so on. Among them, tetracyclododecene is preferable from the viewpoint of improving the solubility of the solvent to facilitate the formation of a surface coating layer by coating.
Examples of the aromatic vinyl compound include: styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, etc.
As the monomer other than the olefin optionally copolymerized with the olefin, there may be mentioned, for example: a monomer having an oxygen atom and an ethylenically unsaturated bond, a monomer having a nitrogen atom and an ethylenically unsaturated bond, and the like.
The olefin monomer other than 1 kind, can be used alone, can also be combined with 2 or more.
Examples of the monomer having an oxygen atom and an ethylenically unsaturated bond include: anhydrides such as maleic anhydride, methylmaleic anhydride, dimethylmaleic anhydride, phenylmaleic anhydride, and diphenylmaleic anhydride; maleic acids such as maleic acid, methyl maleic acid, dimethyl maleate, diethyl maleate, dibutyl maleate, monomethyl maleate, etc.; (meth) acrylic acid and (meth) acrylic acid esters such as methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, cycloalkyl (meth) acrylate having a cycloalkyl group with 3 to 20 carbon atoms, benzyl (meth) acrylate, isobornyl (meth) acrylate, and the like; vinyl ester compounds such as vinyl acetate and vinyl propionate; and so on. Among them, from the viewpoint of improving the solvent solubility to facilitate the formation of a surface coating layer by coating, acid anhydride and vinyl ester compounds are preferable, maleic anhydride and vinyl acetate are more preferable, and maleic anhydride is even more preferable.
Examples of the monomer having a nitrogen atom and an ethylenically unsaturated bond include: maleimide compounds and derivatives thereof, nitrile monomers, and the like.
As the maleimide compound and its derivative, for example: a maleimide; n-alkyl-substituted maleimides such as N-methylmaleimide and N-ethylmaleimide; n-aryl-substituted maleimides such as N-phenylmaleimide; and so on. Examples of nitrile monomers include: acrylonitrile, methacrylonitrile, and the like.
Among the above structural units, the polyolefin-based resin preferably contains a structural unit derived from a chain olefin having 2 to 6 carbon atoms (hereinafter also referred to as "chain olefin-based structural unit (a)"), and more preferably contains 1 or more selected from a structural unit derived from ethylene and a structural unit derived from propylene, from the viewpoint of further reducing the amount of adhesion of grinding swarf.
As the polyolefin-based resin, a polyolefin-based resin containing a chain olefin-based structural unit (a) and a structural unit derived from a monomer having an oxygen atom and an ethylenically unsaturated bond (hereinafter also referred to as "structural unit (B) containing an oxygen atom") is preferable from the viewpoint of improving the solubility in a solvent and facilitating the formation of a surface coating layer by coating; a polyolefin resin containing a chain olefin-based structural unit (A) and a structural unit derived from an aromatic vinyl compound (hereinafter also referred to as "aromatic vinyl compound-based structural unit (C)").
When the polyolefin-based resin contains the chain olefin-based structural unit (a) and the structural unit (B) containing an oxygen atom, the content of the chain olefin-based structural unit (a) in the polyolefin-based resin is not particularly limited, but is preferably 80 to 99.5% by mass, more preferably 90 to 99% by mass, and still more preferably 95 to 98.8% by mass.
When the polyolefin-based resin contains the chain olefin-based structural unit (a) and the structural unit (B) containing an oxygen atom, the content of the structural unit (B) containing an oxygen atom in the polyolefin-based resin is not particularly limited, but is preferably 0.5 to 20% by mass, more preferably 1 to 10% by mass, and still more preferably 1.2 to 5% by mass.
When the content of the chain olefin-based constituent unit (a) and the constituent unit (B) containing an oxygen atom is in the above range, good solvent solubility is obtained and the amount of adhered grinding chips tends to be further reduced.
Examples of the polyolefin-based resin containing a chain olefin-based structural unit (a) and a structural unit (B) containing an oxygen atom include: a binary copolymer such as an ethylene-maleic anhydride copolymer, an ethylene-vinyl acetate copolymer, an ethylene- (meth) acrylate copolymer, a propylene-maleic anhydride copolymer, a propylene-vinyl acetate copolymer, or a propylene- (meth) acrylate copolymer; a multi-polymer such as an ethylene-maleic anhydride-vinyl acetate copolymer, an ethylene-maleic anhydride- (meth) acrylate copolymer, an ethylene-vinyl acetate- (meth) acrylate copolymer, a propylene-maleic anhydride-vinyl acetate copolymer, a propylene-maleic anhydride- (meth) acrylate copolymer, a propylene-vinyl acetate- (meth) acrylate copolymer, an ethylene-propylene-maleic anhydride copolymer, an ethylene-propylene-vinyl acetate copolymer, an ethylene-propylene- (meth) acrylate copolymer, an ethylene-butylene-maleic anhydride copolymer, an ethylene-butylene-vinyl acetate copolymer, an ethylene-butylene- (meth) acrylate copolymer, a propylene-butylene-maleic anhydride copolymer, a propylene-butylene-vinyl acetate copolymer, and a propylene-butylene- (meth) acrylate copolymer; and so on.
Among them, a propylene-butene-maleic anhydride copolymer is preferable from the viewpoint of further reducing the amount of adhered grinding chips and from the viewpoint of improving the solvent solubility to facilitate the formation of a surface coating by coating.
When the polyolefin-based resin contains the chain olefin-based structural unit (a) and the aromatic vinyl compound-based structural unit (C), the content of the chain olefin-based structural unit (a) in the polyolefin-based resin is not particularly limited, but is preferably 5 to 60% by mass, more preferably 10 to 50% by mass, and still more preferably 20 to 40% by mass.
When the polyolefin-based resin contains the chain olefin-based structural unit (a) and the aromatic vinyl compound-based structural unit (C), the content of the aromatic vinyl compound-based structural unit (C) in the polyolefin-based resin is not particularly limited, but is preferably 40 to 95% by mass, more preferably 50 to 90% by mass, and still more preferably 60 to 80% by mass.
When the content of the chain olefin-based constituent unit (a) and the aromatic vinyl compound-based constituent unit (C) is in the above range, good solvent solubility is obtained, and the amount of adhered grinding chips tends to be further reduced.
Examples of the polyolefin resin containing the chain olefin structural unit (a) and the aromatic vinyl compound structural unit (C) include: hydrogenated products of styrene-butadiene-styrene block copolymers, hydrogenated products of styrene-isoprene-styrene block copolymers, and the like. Examples of the hydrogenated product of the styrene-butadiene-styrene block copolymer include SEBS obtained by completely hydrogenating carbon-carbon double bonds in a butadiene block, and SBBS obtained by partially hydrogenating carbon-carbon double bonds at 1, 2-bonding sites in a butadiene block. Among them, SEBS is preferable.
The polyolefin-based resin may be other than the above-described one as long as it can form a surface coating layer. Examples of the polyolefin-based resin other than the above include: polyolefin resins composed only of chain olefin structural units (a), such as polyethylene, polypropylene, polybutadiene, ethylene-propylene copolymers, ethylene-butene copolymers, and propylene-butene copolymers; polyolefin resins composed only of aromatic vinyl compound-based structural units (C), such as polystyrene; and so on.
The surface coating layer-forming composition may or may not contain a resin other than the polyolefin-based resin.
The content of the polyolefin-based resin in the resin component is preferably 90 to 100 mass%, more preferably 95 to 100 mass%, and even more preferably 98 to 100 mass%, from the viewpoint of further reducing the amount of adhering grinding chips and from the viewpoint of further improving the transportability.
[ heteroatom content of resin component ]
The content of the hetero atom in the resin component is not particularly limited, but is preferably 7% by mass or less, more preferably 0.2 to 4% by mass, and still more preferably 0.5 to 1% by mass.
When the content of the hetero atom in the resin component is not more than the above upper limit, the amount of the attached grinding chips tends to be further reduced. When the content of the heteroatom in the resin component is not less than the lower limit, the solvent solubility of the resin component is improved, and the surface coating layer formed by coating the resin component tends to be easily formed.
[ solubility in solvent of resin component ]
From the viewpoint of facilitating the formation of a surface coating layer by coating, the resin component preferably has solubility with respect to an organic solvent. Specifically, the resin component is preferably dissolved in toluene at 23 ℃ by 1 mass% or more, more preferably 5 mass% or more, and still more preferably 8 mass% or more.
[ content of resin component ]
The content of the resin component in the top coat layer-forming composition is preferably 50 to 99% by mass, more preferably 60 to 90% by mass, and still more preferably 70 to 85% by mass, based on the total amount (100% by mass) of the active ingredients in the top coat layer-forming composition.
When the content of the resin component is not less than the lower limit, the amount of adhered grinding chips tends to be further reduced. When the content of the resin component is not more than the above upper limit, the improvement of the carrying property by the addition of the slip property improving component tends to be easily obtained.
In the present embodiment, the active ingredient of the top coat layer-forming composition is a component obtained by removing components such as an organic solvent, which are removed in the process of forming the top coat layer, from the components contained in the top coat layer-forming composition.
(slipping property improving component)
The sliding property improving component contained in the surface coating layer forming composition is a component added for reducing the static friction coefficient of the surface coating layer.
As the slidability-improving component, a compound having a low surface free energy is suitable, and examples thereof include: a resin having a hydrocarbon group in a side chain, a resin having a fluorine atom in a main chain or a side chain, and the like. Specific examples thereof include: among these, an organic silicon compound is preferable from the viewpoint of handling properties.
[ organosilicon Compound ]
The organosilicon compound is not particularly limited as long as it is a polymer having a polydiorganosiloxane structure.
Examples of the polydiorganosiloxane structure contained in the organosilicon compound include a structure having a repeating unit represented by the following general formula (1).
[ chemical formula 1]
Figure BDA0003866518650000111
( Wherein R is a hydrocarbon group having 1 to 6 carbon atoms. * Indicating the bonding site. )
The hydrocarbon group having 1 to 6 carbon atoms represented by R preferably has 1 to 4 carbon atoms, more preferably 1 or 2 carbon atoms, and still more preferably 1 carbon atom.
Examples of the hydrocarbon group having 1 to 6 carbon atoms represented by R include: an alkyl group having 1 to 5 carbon atoms such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, and an n-pentyl group; a phenyl group; and so on. Among them, methyl is preferable.
The organosilicon compound may also have a reactive functional group.
When the organosilicon compound has a reactive functional group, a reaction between the organosilicon compounds or a reaction between the organosilicon compound and another component can occur, and bleeding of the organosilicon compound from the surface coating layer or the like can be made difficult.
Examples of the reactive functional group include: functional groups containing an ethylenically unsaturated bond such as a vinyl group and a (meth) acryloyl group; glycidyl, amino, carboxyl, thiol, hydroxyl, and the like. Among them, a functional group containing an ethylenically unsaturated bond is preferable, and a (meth) acryloyl group is more preferable. In the present specification, the term "ethylenically unsaturated bond" refers to a carbon-carbon double bond capable of undergoing an addition reaction, and does not include a double bond of an aromatic ring. In addition, the (meth) acryloyl group may constitute a (meth) acryloyloxy group.
In the case where the organosilicon compound has a reactive functional group, the organosilicon compound may have a reactive functional group at the terminal, may have a reactive functional group in the side chain, and preferably has a reactive functional group at the terminal.
In the case where the organosilicon compound has a reactive functional group at the terminal, the organosilicon compound may have a reactive functional group at one terminal or may have a reactive functional group at both terminals, and preferably has a reactive functional group at both terminals.
When the organosilicon compound has a reactive functional group, the reactive functional group equivalent of the organosilicon compound is not particularly limited, but is preferably 500 to 10000g/mol, more preferably 1000 to 7000g/mol, and further preferably 1500 to 5000g/mol.
The organosilicon compound may be a linear polymer or a branched polymer, but is preferably a linear polymer.
That is, the organosilicon compound is preferably a linear polymer having a reactive functional group at both terminals. Examples of such an organosilicon compound include compounds represented by the following general formula (2).
[ chemical formula 2]
Figure BDA0003866518650000121
( Wherein R is as described in the above general formula (1). X is independently a 2-valent aliphatic hydrocarbon group having 1 to 5 carbon atoms, and Y is independently a reactive functional group. )
Preferred embodiments of R and preferred embodiments of the reactive functional group represented by Y are as described above.
Examples of the aliphatic hydrocarbon group having a valence of 2 and having 1 to 5 carbon atoms represented by X include: alkylene groups such as methanediyl, ethane-1, 2-diyl, ethane-1, 1-diyl, n-propane-1, 3-diyl, n-propane-1, 2-diyl, 1, 4-n-butyl, 1, 2-tert-butyl, and 1, 5-pentyl.
The weight average molecular weight (Mw) of the organosilicon compound is not particularly limited, but is preferably 1000 to 20000, more preferably 2000 to 17000, and still more preferably 3000 to 15000.
When the weight average molecular weight (Mw) of the organosilicon compound is not less than the lower limit, surface segregation of the organosilicon compound is suppressed, and the film-forming property of the surface coating layer-forming composition tends to be further improved, and thus the transportability tends to be further improved. When the weight average molecular weight (Mw) of the organosilicon compound is not more than the above upper limit, the workability tends to be further improved.
The sliding property improving component may or may not contain a sliding property improving component other than the organosilicon compound.
The content of the organosilicon compound in the slip property-improving component is preferably 90 to 100 mass%, more preferably 95 to 100 mass%, and even more preferably 98 to 100 mass%, from the viewpoint of further reducing the amount of the adhered grinding chips and from the viewpoint of further improving the transportability.
[ hetero atom content of the slipping property-improving component ]
The content of the hetero atom in the sliding property improving component is not particularly limited, but is preferably 30% by mass or more, more preferably 40 to 80% by mass, and still more preferably 50 to 70% by mass.
[ content of slipping property-improving component ]
The content of the slip property improving component in the top coat layer-forming composition is preferably 0.1 to 30% by mass, more preferably 0.3 to 20% by mass, and still more preferably 0.5 to 10% by mass, based on the total amount (100% by mass) of the active components in the top coat layer-forming composition.
When the content of the slip property improving component is not less than the lower limit value, the amount of adhesion of the grinding chips can be further reduced, and the transportability tends to be more excellent. When the content of the sliding property improving component is not more than the above upper limit, the adhesion between the cushion layer and the surface coating layer tends to be more favorable.
(energy ray-polymerizable polyfunctional Compound)
The surface coating layer-forming composition preferably further contains an energy ray-polymerizable polyfunctional compound. When the energy ray-polymerizable polyfunctional compound is contained in the surface coating layer-forming composition, the adhesive sheet of the present embodiment tends to have excellent adhesion between the surface coating layer and the cushion layer.
The energy ray-polymerizable polyfunctional compound is a compound having 2 or more energy ray-polymerizable functional groups. The number of the energy ray-polymerizable functional groups of the energy ray-polymerizable polyfunctional compound is preferably 2 to 10, more preferably 3 to 8, and still more preferably 4 to 7.
The energy ray-polymerizable functional group of the energy ray-polymerizable polyfunctional compound is preferably a (meth) acryloyl group.
The energy ray-polymerizable polyfunctional compound is preferably a polyfunctional (meth) acrylate monomer.
As the polyfunctional (meth) acrylate monomer, for example, there can be mentioned: 2-functional (meth) acrylate monomers such as 1, 4-butanediol di (meth) acrylate, 1, 6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, neopentyl glycol adipate di (meth) acrylate, hydroxypivalic acid neopentyl glycol di (meth) acrylate, dicyclopentyl di (meth) acrylate, caprolactone-modified dicyclopentenyl di (meth) acrylate, ethylene oxide-modified phosphoric acid di (meth) acrylate, di (acryloxyethyl) isocyanurate, allylated cyclohexyl di (meth) acrylate, and ethylene oxide-modified isocyanurate; trimethylolpropane tri (meth) acrylate, dipentaerythritol tri (meth) acrylate, propionic acid-modified dipentaerythritol tri (meth) acrylate, pentaerythritol tri (meth) acrylate, propylene oxide-modified trimethylolpropane tri (meth) acrylate, tris (acryloyloxyethyl) isocyanurate, bis (acryloyloxyethyl) hydroxyethyl isocyanurate, ethylene oxide isocyanurate-modified triacrylate, epsilon-caprolactone-modified tris (acryloyloxyethyl) isocyanurate, diglycerin tetra (meth) acrylate, pentaerythritol tetra (meth) acrylate, propionic acid-modified dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, caprolactone-modified dipentaerythritol hexa (meth) acrylate, and the like. Among them, dipentaerythritol hexa (meth) acrylate and dipentaerythritol penta (meth) acrylate are preferable, and dipentaerythritol hexaacrylate and dipentaerythritol pentaacrylate are more preferable.
The content of the energy ray-polymerizable polyfunctional compound in the top coat layer-forming composition is preferably 1 to 40% by mass, more preferably 5 to 30% by mass, and even more preferably 10 to 20% by mass, based on the total amount (100% by mass) of the active ingredients in the top coat layer-forming composition.
When the content of the energy ray-polymerizable polyfunctional compound is not less than the lower limit value, the adhesion between the surface coating layer and the buffer layer tends to be excellent. When the content of the energy ray-polymerizable polyfunctional compound is not more than the above upper limit, the reduction in the amount of adhered grinding chips and the improvement in the conveyance property by the addition of the resin component and the slip property improving component tend to be easily achieved.
When the composition for forming a surface coating layer contains the resin component and the energy ray-polymerizable polyfunctional compound, the content of the energy ray-polymerizable polyfunctional compound is preferably 10 to 60 parts by mass, more preferably 14 to 40 parts by mass, and still more preferably 17 to 30 parts by mass, based on 100 parts by mass of the resin component.
When the content of the energy ray-polymerizable polyfunctional compound is not less than the lower limit value, the adhesion between the surface coating layer and the buffer layer tends to be excellent. When the content of the energy ray-polymerizable polyfunctional compound is not more than the above upper limit, the amount of adhered grinding chips and the improvement in the carrying property by the addition of the resin component and the slip property improving component tend to be reduced easily.
(photopolymerization initiator)
When the surface coating layer-forming composition contains an energy ray-polymerizable polyfunctional compound, the surface coating layer-forming composition preferably further contains a photopolymerization initiator.
The photopolymerization initiator may be used alone in 1 kind, or may be used in combination in 2 or more kinds.
Examples of the photopolymerization initiator include: benzoin compounds, acetophenone compounds, acylphosphine oxide compounds, titanocene compounds, thioxanthone compounds, peroxide compounds, and photosensitizers such as amines and quinones, and more specifically, for example: 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzyl phenyl sulfide, tetramethylthiuram monosulfide, azobisisobutyronitrile, bibenzyl, butanedione, 8-chloroanthraquinone, phenylbis (2, 4, 6-trimethylbenzoyl) phosphine oxide, and the like.
When the surface coating layer-forming composition contains a photopolymerization initiator, the content thereof is not particularly limited, and is preferably 0.01 to 10 parts by mass, more preferably 0.03 to 7 parts by mass, and further preferably 0.05 to 5 parts by mass, per 100 parts by mass of the energy ray-polymerizable polyfunctional compound, from the viewpoint of allowing the energy ray polymerization reaction to proceed uniformly and sufficiently.
(other Components)
The surface coating layer may contain other components within a range not impairing the effects of the present invention. As other components, for example: resins other than the above; additives such as antistatic agents, antioxidants, softeners, fillers, rust inhibitors, pigments, dyes, and the like; and so on.
(contact Angle)
The static contact angle of water at 23 ℃ (hereinafter also simply referred to as "water contact angle") with respect to the surface coating of the pressure-sensitive adhesive sheet of the present embodiment is preferably 85 ° or more.
When the water contact angle of the surface coating is 85 ° or more, water containing grinding chips is less likely to adhere to the surface coating, and therefore the amount of adhesion of the grinding chips tends to be further reduced.
From the viewpoint of further reducing the amount of adhesion of the grinding chips, the water contact angle of the surface coating is preferably 90 ° or more, more preferably 95 ° or more, and still more preferably 98 ° or more. The upper limit of the water contact angle of the surface coating layer is not particularly limited, and may be, for example, 150 ° or less, or 110 ° or less, from the viewpoint of ease of production and the like.
The water contact angle of the surface coating layer is a value measured in accordance with JIS R3257.
The thickness of the surface coating layer is not particularly limited, but is preferably 0.05 to 10 μm, more preferably 0.2 to 7 μm, and still more preferably 1 to 4 μm.
When the thickness of the surface coating layer is equal to or greater than the lower limit value, a uniform layer can be formed, the amount of adhesion of the grinding chips can be further reduced, and the transportability tends to be more excellent. When the thickness of the surface coating layer is equal to or less than the upper limit value, the effect of the buffer layer that absorbs irregularities such as foreign matter on the chuck table tends to be obtained easily.
< buffer layer >
The cushion layer is a layer provided between the base material and the surface coating layer, and serves to absorb vibration, impact, and the like generated during back grinding and prevent cracks from being generated in the workpiece. Further, by providing the cushion layer, it is possible to absorb irregularities such as foreign matters existing on the table of the supporting device, and to improve the holding property of the adhesive sheet obtained by the supporting device.
(composition for Forming cushion layer)
The buffer layer may be formed of the buffer layer-forming composition.
From the viewpoint of obtaining physical properties suitable for the buffer layer, the buffer layer is preferably a layer obtained by curing an energy ray-curable composition for buffer layer formation containing an energy ray-polymerizable compound.
The composition for forming a buffer layer preferably contains urethane (meth) acrylate (a 1) as the energy ray polymerizable compound. By adding the urethane (meth) acrylate (a 1) to the composition for forming a buffer layer, the storage modulus and the like of the buffer layer tend to be adjusted to a good range.
From the same viewpoint, the buffer layer-forming composition more preferably contains not less than 1 selected from the group consisting of the polymerizable compound (a 2) having an alicyclic group or heterocyclic group having 6 to 20 ring atoms and the polymerizable compound (a 3) having a functional group, in addition to the urethane (meth) acrylate (a 1), and further preferably contains the polymerizable compound (a 2) having an alicyclic group or heterocyclic group having 6 to 20 ring atoms and the polymerizable compound (a 3) having a functional group, in addition to the urethane (meth) acrylate (a 1).
In the present specification, the number of ring-forming atoms indicates the number of atoms constituting the ring itself in a compound having a structure in which atoms are bonded in a ring form, and atoms not constituting the ring (for example, hydrogen atoms bonded to atoms constituting the ring) and atoms included in a substituent when the ring is substituted with a substituent are not included in the number of ring-forming atoms.
[ urethane (meth) acrylate (a 1) ]
The urethane (meth) acrylate (a 1) is a compound having a (meth) acryloyl group and a urethane bond, and has a property of being polymerized by irradiation with an energy ray.
The urethane (meth) acrylate (a 1) may be used alone in 1 kind, or may be used in combination in 2 or more kinds.
The weight average molecular weight (Mw) of the urethane (meth) acrylate (a 1) is not particularly limited, but is preferably 1000 to 100000, more preferably 2000 to 60000, and further preferably 3000 to 20000.
In the present embodiment, the weight average molecular weight (Mw) is a value in terms of standard polystyrene measured by a Gel Permeation Chromatography (GPC) method, specifically, a value measured by the method described in examples.
The number of (meth) acryloyl groups in 1 molecule of the urethane (meth) acrylate (a 1) is not particularly limited, but is preferably 1 to 4, more preferably 1 to 3, and still more preferably 1 or 2.
The urethane (meth) acrylate (a 1) can be obtained, for example, by reacting a (meth) acrylate having a hydroxyl group with an isocyanate-terminated urethane prepolymer obtained by reacting a polyol compound with a polyisocyanate compound.
The polyol compound is not particularly limited as long as it is a compound having 2 or more hydroxyl groups.
Specific examples of the polyol compound include: alkylene glycol, polyether polyol, polyester polyol, polycarbonate polyol and the like. Among them, polyester polyols are preferable.
The polyol compound may be any of 2-functional diols, 3-functional triols, and 4-or more-functional polyols, preferably 2-functional diols, and more preferably polyester diols.
The polyol compound may be used alone in 1 kind, or may be used in combination in 2 or more kinds.
As the polyisocyanate compound, for example, there can be mentioned: aliphatic polyisocyanates such as tetramethylene diisocyanate, hexamethylene diisocyanate, and trimethylhexamethylene diisocyanate; alicyclic diisocyanates such as isophorone diisocyanate, norbornane diisocyanate, dicyclohexylmethane-4, 4' -diisocyanate, dicyclohexylmethane-2, 4' -diisocyanate and ω, ω ' -diisocyanate dimethylcyclohexane; aromatic diisocyanates such as 4,4' -diphenylmethane diisocyanate, tolylene diisocyanate, xylylene diisocyanate, tolidine diisocyanate, tetramethylene xylylene diisocyanate, and naphthalene-1, 5-diisocyanate; and so on. Among them, isophorone diisocyanate, hexamethylene diisocyanate, and xylylene diisocyanate are preferable.
The polyisocyanate compound may be used alone in 1 kind, or may be used in combination in 2 or more kinds.
The (meth) acrylate having a hydroxyl group to be reacted with the isocyanate terminated urethane prepolymer is not particularly limited as long as it is a compound having a hydroxyl group and a (meth) acryloyl group in at least 1 molecule.
Examples of the (meth) acrylate having a hydroxyl group include: hydroxyalkyl (meth) acrylates such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 4-hydroxycyclohexyl (meth) acrylate, 5-hydroxycyclooctyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, pentaerythritol tri (meth) acrylate, polyethylene glycol mono (meth) acrylate, and polypropylene glycol mono (meth) acrylate; hydroxyl group-containing (meth) acrylamides such as N-methylol (meth) acrylamide; a reactant obtained by reacting (meth) acrylic acid with a diglycidyl ester of vinyl alcohol, vinylphenol, or bisphenol a; and so on. Among them, hydroxyalkyl (meth) acrylates are preferable, and 2-hydroxyethyl (meth) acrylate is more preferable.
The hydroxyl group-containing (meth) acrylate may be used alone in 1 kind, or may be used in combination in 2 or more kinds.
The conditions for reacting the isocyanate-terminated urethane prepolymer with the (meth) acrylate having a hydroxyl group are not particularly limited, and for example, the reaction may be carried out in the presence of an organic solvent, a catalyst, or the like added as needed at 60 to 100 ℃ for 1 to 4 hours.
The content of the urethane (meth) acrylate (a 1) in the composition for forming the buffer layer is not particularly limited, and is preferably 10 to 70% by mass, more preferably 20 to 60% by mass, and further preferably 30 to 50% by mass, based on the total amount (100% by mass) of the active ingredients in the composition for forming the buffer layer.
In this embodiment, the active ingredient of the composition for forming a buffer layer is a component obtained by removing a component such as an organic solvent, which is to be removed in the process of forming the buffer layer, from the components contained in the composition for forming a buffer layer.
[ polymerizable Compound (a 2) having an alicyclic group or heterocyclic group having 6 to 20 Ring-Forming atoms ]
The composition for forming a buffer layer tends to have improved film-forming properties by containing a polymerizable compound (a 2) having an alicyclic group or a heterocyclic group having 6 to 20 ring atoms (hereinafter also referred to as "polymerizable compound (a 2) having an alicyclic group or a heterocyclic group").
Examples of the atom forming the ring structure of the heterocyclic group include: carbon atom, nitrogen atom, oxygen atom, sulfur atom, and the like.
The polymerizable compound (a 2) having an alicyclic group or heterocyclic group may be used alone in 1 kind, or may be used in combination in 2 or more kinds.
The polymerizable compound (a 2) having an alicyclic group or heterocyclic group is preferably a compound having a (meth) acryloyl group.
The number of (meth) acryloyl groups in 1 molecule of the polymerizable compound (a 2) having an alicyclic group or heterocyclic group is not particularly limited, but is preferably 1 or more, more preferably 1 or 2, and still more preferably 1.
The number of ring atoms of the alicyclic group or heterocyclic group contained in the polymerizable compound (a 2) having an alicyclic group or heterocyclic group is 6 to 20, preferably 6 to 18, more preferably 6 to 16, and still more preferably 7 to 12.
Examples of the polymerizable compound (a 2) having an alicyclic group or a heterocyclic group include: (meth) acrylic esters having an alicyclic group such as isobornyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentenyloxy (meth) acrylate, cyclohexyl (meth) acrylate, and adamantyl (meth) acrylate; heterocyclic group-containing (meth) acrylates such as tetrahydrofurfuryl (meth) acrylate and morpholinyl (meth) acrylate; and so on. Among them, preferred are (meth) acrylates containing an alicyclic group, and more preferred is isobornyl (meth) acrylate.
The content of the polymerizable compound (a 2) having an alicyclic group or a heterocyclic group in the composition for forming a buffer layer is not particularly limited, and is preferably 10 to 70% by mass, more preferably 20 to 60% by mass, and even more preferably 30 to 50% by mass, based on the total amount (100% by mass) of the active ingredients in the composition for forming a buffer layer.
[ polymerizable Compound (a 3) having functional group ]
The composition for forming a buffer layer tends to be able to adjust the viscosity of the composition for forming a buffer layer to an appropriate range by containing the polymerizable compound (a 3) having a functional group.
The polymerizable compound (a 3) having a functional group may be used alone in 1 kind, or may be used in combination in 2 or more kinds.
Examples of the functional group of the polymerizable compound (a 3) having a functional group include: hydroxyl, epoxy, amide, amino, and the like.
The number of functional groups in 1 molecule of the polymerizable compound (a 3) having a functional group is 1 or more, preferably 1 to 3, more preferably 1 or 2, and still more preferably 1.
The polymerizable compound (a 3) having a functional group is preferably a compound having a (meth) acryloyl group together with a functional group.
The number of (meth) acryloyl groups in 1 molecule of the polymerizable compound (a 3) having a functional group is not particularly limited, but is preferably 1 or more, more preferably 1 or 2, and still more preferably 1.
Examples of the polymerizable compound (a 3) having a functional group include: a hydroxyl group-containing polymerizable compound, an epoxy group-containing polymerizable compound, an amide group-containing polymerizable compound, an amino group-containing polymerizable compound, and the like.
Examples of the hydroxyl group-containing polymerizable compound include: hydroxyl group-containing (meth) acrylates such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 3-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, and 2-hydroxy-3-phenoxypropyl (meth) acrylate; vinyl ether compounds such as hydroxyethyl vinyl ether and hydroxybutyl vinyl ether; and so on.
Examples of the polymerizable compound containing an epoxy group include: glycidyl (meth) acrylate, methyl glycidyl (meth) acrylate, allyl glycidyl ether, and the like.
Examples of the amide group-containing polymerizable compound include: (meth) acrylamide, N-dimethyl (meth) acrylamide, N-butyl (meth) acrylamide, N-methylol (meth) acrylamide, N-methylolpropane (meth) acrylamide, N-methoxymethyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide, N-vinylformamide, and the like.
Examples of the amino group-containing polymerizable compound include: and amino group-containing (meth) acrylates such as primary amino group-containing (meth) acrylates, secondary amino group-containing (meth) acrylates, and tertiary amino group-containing (meth) acrylates.
Among these, hydroxyl group-containing (meth) acrylates are preferable, and hydroxyl group-containing (meth) acrylates having an aromatic ring such as 2-hydroxy-3-phenoxypropyl (meth) acrylate are more preferable.
The content of the polymerizable compound (a 3) having a functional group in the composition for forming a buffer layer is not particularly limited, and is preferably 5 to 40% by mass, more preferably 10 to 30% by mass, and still more preferably 15 to 25% by mass, based on the total amount (100% by mass) of the active ingredients of the composition for forming a buffer layer.
[ other polymerizable Compound ]
The composition for forming a buffer layer may contain other polymerizable compounds than the components (a 1) to (a 3) within a range not impairing the effects of the present invention.
Examples of the other polymerizable compounds include: an alkyl (meth) acrylate having an alkyl group having 1 to 20 carbon atoms; vinyl compounds such as styrene, N-vinylpyrrolidone and N-vinylcaprolactam; and so on.
The other polymerizable compounds may be used alone in 1 kind, or may be used in combination in 2 or more kinds.
The content of the other polymerizable compound in the composition for forming a buffer layer is not particularly limited, and is preferably 0 to 20 mass%, more preferably 0 to 10 mass%, and further preferably 0 to 2 mass% with respect to the total amount (100 mass%) of the active ingredients of the composition for forming a buffer layer.
[ photopolymerization initiator ]
The composition for forming a buffer layer containing an energy ray-polymerizable compound preferably further contains a photopolymerization initiator from the viewpoint of reducing the polymerization time and the energy ray irradiation amount by the energy ray irradiation.
The photopolymerization initiator may be used alone in 1 kind, or may be used in combination in 2 or more kinds.
Examples of the photopolymerization initiator include: benzoin compounds, acetophenone compounds, acyl phosphine oxide compounds, titanocene compounds, thioxanthone compounds, peroxide compounds, and photosensitizers such as amines and quinones, and more specifically, for example: 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzyl phenyl sulfide, tetramethylthiuram monosulfide, azobisisobutyronitrile, bibenzyl, butanedione, 8-chloroanthraquinone, phenylbis (2, 4, 6-trimethylbenzoyl) phosphine oxide, and the like. Among them, 1-hydroxycyclohexyl phenyl ketone is preferable.
The content of the photopolymerization initiator in the composition for forming a buffer layer is not particularly limited, and is preferably 0.05 to 15 parts by mass, more preferably 0.1 to 10 parts by mass, and even more preferably 0.3 to 5 parts by mass, based on 100 parts by mass of the total amount of the energy ray-polymerizable compounds, from the viewpoint of allowing the energy ray curing reaction to proceed uniformly and sufficiently.
(other Components)
The composition for forming a buffer layer may contain other components within a range not impairing the effects of the present invention. As other components, for example: a resin component other than the above resin; antistatic agent, antioxidant, softening agent, filler, antirust agent, pigment, dye and other additives; and so on.
The content of the other resin component in the composition for forming a buffer layer is not particularly limited, and is preferably 0 to 20 mass%, more preferably 0 to 10 mass%, and further preferably 0 to 2 mass% with respect to the total amount (100 mass%) of the active ingredients of the composition for forming a buffer layer.
The content of the other additives in the composition for forming a buffer layer is not particularly limited, and various other additives are preferably 0 to 6% by mass, more preferably 0.01 to 5% by mass, and still more preferably 0.1 to 3% by mass, based on the total amount (100% by mass) of the active ingredients in the composition for forming a buffer layer.
(Young's modulus of buffer layer)
The Young's modulus of the buffer layer at 23 ℃ is smaller than that of the base material at 23 ℃, and specifically, it is preferably smaller than 1200MPa, more preferably 900MPa or less. The buffer layer preferably has a Young's modulus at 23 ℃ of 50MPa or more, more preferably 100MPa or more.
When the young's modulus of the cushion layer at 23 ℃ is not more than the above upper limit value, the cushion layer has an effect of absorbing vibration, impact, and the like generated at the time of back grinding, and the adhesive sheet tends to have improved holding properties. When the young's modulus of the cushion layer at 23 ℃ is not less than the lower limit value, the cushion layer tends to be prevented from being excessively deformed when the workpiece is machined.
The Young's modulus of the buffer layer at 23 ℃ can be measured at a test speed of 200 mm/min in accordance with JIS K7127.
(stress relaxation Rate of buffer layer)
The stress relaxation rate of the buffer layer is not particularly limited, but is preferably 70 to 100%, more preferably 75 to 100%, and still more preferably 78 to 98%.
When the stress relaxation rate of the cushion layer is in the above range, there are effects of absorbing vibration, shock, and the like generated at the time of back grinding, and the holding property of the adhesive sheet tends to be increased.
As the stress relaxation rate of the buffer layer, a material obtained by cutting a buffer layer having a thickness of 200 μm to 15mm × 140mm was used as a test piece, and a stress A (N/m) obtained by stretching 10% at 200 mm/min was used with 20mm of both ends of the test piece sandwiched therebetween 2 ) And stress B (N/m) after 1 minute of cessation of elongation 2 ) The value of (d) is obtained by the following equation.
Stress relaxation rate (%) =100 × (a-B)/a (%)
(thickness of buffer layer)
The thickness of the buffer layer is not particularly limited, but is preferably 5 to 70 μm, more preferably 7 to 50 μm, and still more preferably 10 to 40 μm.
When the thickness of the cushion layer is equal to or greater than the lower limit value, the cushion layer has an effect of absorbing vibration, shock, and the like generated during back grinding, and the adhesive sheet tends to have higher holding property. When the thickness of the cushion layer is equal to or less than the upper limit value, the cushion layer tends to be prevented from being excessively deformed when the workpiece is machined.
< adhesive layer >
The pressure-sensitive adhesive layer is a layer provided on the side of the base opposite to the cushion layer, and is a layer to be attached to a workpiece.
The adhesive layer is preferably a layer formed of an energy ray-curable adhesive. By forming the pressure-sensitive adhesive layer with an energy ray-curable pressure-sensitive adhesive, the surface of the workpiece can be protected well with sufficient adhesiveness before energy ray curing, and the peel force after energy ray curing is reduced, enabling easy peeling from the workpiece.
Examples of the energy ray-curable adhesive include: the following X-type adhesive composition, Y-type adhesive composition, XY-type adhesive composition, and the like.
Adhesive composition of type X: energy ray-curable adhesive composition containing non-energy ray-curable adhesive resin (hereinafter also referred to as "adhesive resin I") and energy ray-curable compound other than adhesive resin
Adhesive composition of type Y: an energy ray-curable adhesive composition containing an energy ray-curable adhesive resin (hereinafter also referred to as "adhesive resin II") in which an unsaturated group is introduced into a side chain of a non-energy ray-curable adhesive resin, and containing no energy ray-curable compound other than the adhesive resin
Adhesive composition of XY type: an energy ray-curable adhesive composition containing the energy ray-curable adhesive resin II and an energy ray-curable compound other than the adhesive resin
Among them, the energy ray-curable adhesive is preferably an XY type adhesive composition. By using the XY type adhesive composition, the following tendency is exhibited: has sufficient adhesiveness before curing, and on the other hand, can sufficiently reduce the peeling force with respect to the workpiece after curing.
The adhesive forming the adhesive layer may be a layer formed of a non-energy ray-curable adhesive which is not cured even when irradiated with an energy ray.
Examples of the non-energy ray-curable adhesive include adhesives containing the adhesive resin I but not containing the adhesive resin II and the energy ray-curable compound.
Next, each component constituting the pressure-sensitive adhesive layer will be described in more detail.
In the following description, the term "adhesive resin" is used as a term indicating one or both of the adhesive resin I and the adhesive resin II. In the following description, the term "pressure-sensitive adhesive composition" is a concept including an X-type pressure-sensitive adhesive composition, a Y-type pressure-sensitive adhesive composition, an XY-type pressure-sensitive adhesive composition, and other pressure-sensitive adhesive compositions.
Examples of the adhesive resin include: acrylic resins, urethane resins, rubber resins, silicone resins, and the like. Among them, acrylic resins are preferable.
(acrylic resin)
The acrylic resin preferably contains a structural unit derived from an alkyl (meth) acrylate.
Examples of the alkyl (meth) acrylate include: an alkyl (meth) acrylate in which the alkyl group has 1 to 20 carbon atoms.
The alkyl group of the alkyl (meth) acrylate may be linear or branched.
From the viewpoint of further improving the adhesive strength of the adhesive layer, the acrylic resin preferably contains a structural unit derived from an alkyl (meth) acrylate having an alkyl group with 4 or more carbon atoms.
The number of structural units derived from an alkyl (meth) acrylate having an alkyl group of 4 or more carbon atoms contained in the acrylic resin may be 1 or 2 or more by itself.
The alkyl group of the alkyl (meth) acrylate having an alkyl group of 4 or more carbon atoms preferably has 4 to 12 carbon atoms, more preferably 4 to 8 carbon atoms, and still more preferably 4 to 6 carbon atoms.
Examples of the alkyl (meth) acrylate having an alkyl group with 4 or more carbon atoms include: butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, undecyl (meth) acrylate, dodecyl (meth) acrylate, and the like. Among these, butyl (meth) acrylate is preferable, and butyl acrylate is more preferable.
When the acrylic resin contains a structural unit derived from an alkyl (meth) acrylate having an alkyl group with 4 or more carbon atoms, the content thereof in the acrylic resin is preferably 30 to 90% by mass, more preferably 40 to 80% by mass, and still more preferably 45 to 60% by mass, from the viewpoint of further improving the adhesive strength of the pressure-sensitive adhesive layer.
From the viewpoint of improving the storage modulus G' and the adhesive properties of the pressure-sensitive adhesive layer, the acrylic resin preferably contains a structural unit derived from an alkyl (meth) acrylate having an alkyl group with 4 or more carbon atoms and a structural unit derived from an alkyl (meth) acrylate having an alkyl group with 1 to 3 carbon atoms.
The number of the structural units derived from the alkyl (meth) acrylate having an alkyl group of 1 to 3 carbon atoms contained in the acrylic resin may be 1 or 2 or more.
Examples of the alkyl (meth) acrylate having an alkyl group of 1 to 3 carbon atoms include: methyl (meth) acrylate, ethyl (meth) acrylate, isopropyl (meth) acrylate, n-propyl (meth) acrylate, and the like. Among them, methyl (meth) acrylate and ethyl (meth) acrylate are preferable, methyl (meth) acrylate is more preferable, and methyl methacrylate is further preferable.
When the acrylic resin contains a structural unit derived from an alkyl (meth) acrylate having an alkyl group with 1 to 3 carbon atoms, the content thereof in the acrylic resin is preferably 1 to 35% by mass, more preferably 5 to 30% by mass, and still more preferably 15 to 25% by mass.
The acrylic resin preferably further contains a structural unit derived from a functional group-containing monomer.
By incorporating a structural unit derived from a functional group-containing monomer into the acrylic resin, a functional group which is a crosslinking starting point for reaction with a crosslinking agent can be introduced, or a functional group which can react with an unsaturated group-containing compound to introduce an unsaturated group into a side chain of the acrylic resin can be introduced.
The number of the structural units derived from the functional group-containing monomer contained in the acrylic resin may be 1 or 2 or more.
Examples of the functional group-containing monomer include: hydroxyl group-containing monomers, carboxyl group-containing monomers, amino group-containing monomers, epoxy group-containing monomers, and the like. Among these, hydroxyl group-containing monomers and carboxyl group-containing monomers are preferable, and hydroxyl group-containing monomers are more preferable.
Examples of the hydroxyl group-containing monomer include: hydroxyalkyl (meth) acrylates such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 3-hydroxybutyl (meth) acrylate, and 4-hydroxybutyl (meth) acrylate; unsaturated alcohols such as vinyl alcohol and allyl alcohol; and so on.
Examples of the carboxyl group-containing monomer include: ethylenically unsaturated monocarboxylic acids such as (meth) acrylic acid and crotonic acid; ethylenically unsaturated dicarboxylic acids such as fumaric acid, itaconic acid, maleic acid, and citraconic acid, and anhydrides thereof; 2-carboxyethyl methacrylate; and so on.
When the acrylic resin contains a structural unit derived from a functional group-containing monomer, the content thereof is not particularly limited, but is preferably 5 to 45 mass%, more preferably 15 to 40 mass%, and still more preferably 25 to 35 mass% in the acrylic resin.
The acrylic resin may contain, in addition to the above-mentioned structural units, structural units derived from other monomers copolymerizable with the acrylic monomer.
The structural units derived from other monomers contained in the acrylic resin may be 1 or 2 or more kinds alone.
Examples of other monomers include: styrene, alpha-methylstyrene, vinyltoluene, vinyl formate, vinyl acetate, acrylonitrile, acrylamide, and the like.
In order to impart energy ray curability, the acrylic resin may further contain an energy ray-polymerizable unsaturated group.
The unsaturated group can be introduced, for example, by reacting a functional group of the acrylic resin containing a structural unit derived from the functional group-containing monomer with a reactive substituent group of a compound having a reactive substituent group with the functional group and an unsaturated group (hereinafter, also referred to as "unsaturated group-containing compound"). The unsaturated group-containing compound may be used alone in 1 kind, or may be used in combination in 2 or more kinds.
Examples of the unsaturated group contained in the unsaturated group-containing compound include: (meth) acryloyl, vinyl, allyl, and the like. Among them, a (meth) acryloyl group is preferable.
Examples of the reactive substituent group of the unsaturated group-containing compound include: isocyanate groups, glycidyl groups, and the like.
Examples of the unsaturated group-containing compound include: (meth) acryloyloxyethyl isocyanate, (meth) acryloyl isocyanate, (meth) glycidyl acrylate, and the like.
When the acrylic resin containing a structural unit derived from the functional group-containing monomer is reacted with the unsaturated group-containing compound, the ratio of the functional group to be reacted with the unsaturated group-containing compound in the total number of functional groups in the acrylic resin is not particularly limited, but is preferably 60 to 98 mol%, more preferably 70 to 95 mol%, and still more preferably 80 to 93 mol%.
When the ratio of the functional group that reacts with the unsaturated group-containing compound is in the above range, sufficient energy ray curability can be imparted to the acrylic resin, and the acrylic resin can be crosslinked by reacting the functional group that does not react with the unsaturated group-containing compound with the crosslinking agent.
The weight average molecular weight (Mw) of the acrylic resin is not particularly limited, but is preferably 30 to 150 ten thousand, more preferably 35 to 100 ten thousand, and further preferably 40 to 60 ten thousand.
When the weight average molecular weight (Mw) of the acrylic resin is in the above range, the adhesive force and cohesive force of the adhesive layer tend to be further improved.
(energy ray-curable Compound)
The energy ray-curable compound contained in the X-type or XY-type pressure-sensitive adhesive composition is preferably a monomer or oligomer having an unsaturated group in the molecule and being curable by irradiation with an energy ray.
Examples of the energy ray-curable compound include: polyhydric (meth) acrylate monomers such as trimethylolpropane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, 1, 4-butanediol di (meth) acrylate, and 1, 6-hexanediol di (meth) acrylate; oligomers such as urethane (meth) acrylate, polyester (meth) acrylate, polyether (meth) acrylate, and epoxy (meth) acrylate; and so on. Among them, urethane (meth) acrylate oligomers are preferable from the viewpoint that the molecular weight is high and the elastic modulus of the pressure-sensitive adhesive layer is not easily lowered.
The molecular weight of the energy ray-curable compound is not particularly limited, but is preferably 100 to 12000, more preferably 200 to 10000, still more preferably 400 to 8000, and still more preferably 600 to 6000. When the energy ray-curable compound is an oligomer, the molecular weight refers to a weight average molecular weight (Mw).
The content of the energy ray-curable compound in the X-type adhesive composition is not particularly limited, and is preferably 40 to 200 parts by mass, more preferably 50 to 150 parts by mass, and still more preferably 60 to 90 parts by mass, based on 100 parts by mass of the adhesive resin.
When the content of the energy ray-curable compound in the X-type adhesive composition is in the above range, the balance between the adhesive strength before irradiation with energy rays and the peelability after irradiation with energy rays tends to be good.
The content of the energy ray-curable compound in the XY type adhesive composition is not particularly limited, and is preferably 1 to 30 parts by mass, more preferably 2 to 20 parts by mass, and still more preferably 3 to 15 parts by mass, based on 100 parts by mass of the adhesive resin.
When the content of the energy ray-curable compound in the XY type adhesive composition is in the above range, the balance between the adhesive force before the energy ray irradiation and the peelability after the energy ray irradiation tends to be good. In the XY type adhesive composition, since the adhesive resin is energy ray-curable, even if the content of the energy ray-curable compound is small, the peeling force tends to be sufficiently reduced after the energy ray irradiation.
(crosslinking agent)
The adhesive composition preferably further contains a crosslinking agent.
The crosslinking agent is a component that crosslinks the adhesive resins by reacting with a functional group derived from a functional group-containing monomer that the adhesive resins have, for example.
The crosslinking agent can be used alone in 1 kind, also can be combined with more than 2 kinds.
Examples of the crosslinking agent include: isocyanate crosslinking agents such as toluene diisocyanate, hexamethylene diisocyanate, and adducts thereof; epoxy crosslinking agents such as ethylene glycol glycidyl ether; aziridine crosslinking agents such as hexa [1- (2-methyl) -aziridinyl ] triphosphotriazine; chelate crosslinking agents such as aluminum chelate compounds; and so on. Among them, isocyanate-based crosslinking agents are preferable from the viewpoint of improving cohesive force to further improve adhesive force and from the viewpoint of easiness of acquisition.
When the pressure-sensitive adhesive composition contains a crosslinking agent, the content thereof is not particularly limited, and from the viewpoint of appropriately proceeding the crosslinking reaction, the content is preferably 0.01 to 10 parts by mass, more preferably 0.03 to 7 parts by mass, and still more preferably 0.05 to 4 parts by mass, relative to 100 parts by mass of the pressure-sensitive adhesive resin.
(photopolymerization initiator)
When the adhesive is an energy ray-curable adhesive, the adhesive composition preferably further contains a photopolymerization initiator. By including a photopolymerization initiator in the energy ray-curable adhesive, the curing reaction of the energy ray-curable adhesive tends to be sufficiently advanced even with a relatively low energy ray such as ultraviolet rays.
The photopolymerization initiator may be used alone in 1 kind, or may be used in combination in 2 or more kinds.
Examples of the photopolymerization initiator include: benzoin compounds, acetophenone compounds, acylphosphine oxide compounds, titanocene compounds, thioxanthone compounds, peroxide compounds, and photosensitizers such as amines and quinones, and more specifically, for example: 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzyl phenyl sulfide, tetramethylthiuram monosulfide, azobisisobutyronitrile, bibenzyl, butanedione, 8-chloroanthraquinone, phenylbis (2, 4, 6-trimethylbenzoyl) phosphine oxide, and the like.
When the energy ray-curable adhesive contains a photopolymerization initiator, the content thereof is not particularly limited, and is preferably 0.01 to 10 parts by mass, more preferably 0.03 to 7 parts by mass, and even more preferably 0.05 to 5 parts by mass, based on 100 parts by mass of the adhesive resin, from the viewpoint of allowing the energy ray curing reaction to proceed uniformly and sufficiently.
(other additives)
The adhesive composition may contain other additives within a range not impairing the effects of the present invention. As other additives, for example: antistatic agent, antioxidant, softening agent, filler, antirust agent, pigment, dye, etc.
The content of other additives in the pressure-sensitive adhesive composition is not particularly limited, and various other additives are preferably 0 to 6% by mass, more preferably 0.01 to 5% by mass, and still more preferably 0.1 to 3% by mass, based on the total amount (100% by mass) of the active ingredients in the pressure-sensitive adhesive composition.
In the present embodiment, the active ingredient of the pressure-sensitive adhesive composition refers to a component obtained by removing components such as an organic solvent, which are removed in the process of forming the pressure-sensitive adhesive layer, from the components contained in the pressure-sensitive adhesive composition.
(organic solvent)
The pressure-sensitive adhesive composition may be diluted with an organic solvent to be in the form of a solution from the viewpoint of further improving the coatability with respect to a substrate, a release sheet, or the like.
Examples of the organic solvent include: methyl ethyl ketone, acetone, ethyl acetate tetrahydrofuran, di
Figure BDA0003866518650000281
Alkanes, cyclohexane, n-hexane, toluene, xylene, n-propanol, isopropanol, and the like.
The organic solvent may be used alone in 1 kind, or may be used in combination in 2 or more kinds.
The organic solvent may be used as it is, or 1 or more organic solvents other than the organic solvent used for synthesis may be added.
The storage modulus G' of the pressure-sensitive adhesive layer at 23 ℃ is not particularly limited, but is preferably 0.05 to 0.5MPa, more preferably 0.1 to 0.4MPa, and still more preferably 0.12 to 0.3MPa.
When the storage modulus G' of the pressure-sensitive adhesive layer at 23 ℃ is in the above range, even when the surface of the work has irregularities, the pressure-sensitive adhesive layer having excellent conformability to the irregularities tends to be obtained, and the surface of the work can be protected more favorably during processing.
The storage modulus G 'of the pressure-sensitive adhesive layer refers to the storage modulus G' before being cured by irradiation with an energy ray when the pressure-sensitive adhesive layer is formed of an energy ray-curable pressure-sensitive adhesive.
The storage modulus G' of the adhesive layer at 23 ℃ can be measured by a torsional shear method using a viscoelasticity measuring apparatus at a frequency of 1Hz and a measuring temperature of 23 ℃ after cutting the adhesive layer having a thickness of 3mm into a circular shape having a diameter of 8mm to prepare a test piece.
The thickness of the pressure-sensitive adhesive layer is not particularly limited, but is preferably 5 to 100. Mu.m, more preferably 10 to 80 μm, and still more preferably 15 to 60 μm.
When the thickness of the pressure-sensitive adhesive layer is equal to or greater than the lower limit, excellent adhesion is obtained, and the surface of the workpiece tends to be protected more favorably during processing. When the thickness of the pressure-sensitive adhesive layer is equal to or less than the upper limit, the generation of tape scraps can be suppressed when cutting the pressure-sensitive adhesive sheet, and the work tends to be more favorably prevented from being broken.
< substrate >
Examples of the substrate include various resin films. Examples of the resin constituting the resin film include: polyethylenes such as Low Density Polyethylene (LDPE), linear Low Density Polyethylene (LLDPE), and High Density Polyethylene (HDPE); polyolefins such as polypropylene, polybutene, polybutadiene, polymethylpentene, ethylene-norbornene copolymers, norbornene resins, etc.; ethylene copolymers such as ethylene-vinyl acetate copolymers, ethylene- (meth) acrylic acid copolymers, and ethylene- (meth) acrylate copolymers; polyvinyl chloride such as polyvinyl chloride and vinyl chloride copolymer; polyesters such as polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, and wholly aromatic polyesters; polyurethanes, polyimides, polyamides, polycarbonates, fluororesins, polyacetals, modified polyphenylene ethers, polyphenylene sulfides, polysulfones, polyether ketones, acrylic polymers; and so on.
The substrate may be a single-layer film of resin films formed of 1 or 2 or more kinds of resins selected from these resins, or may be a laminated film formed by laminating 2 or more kinds of these resin films. Further, the resin may be a crosslinked film of the above resin, a modified film such as an ionomer film, or the like.
Among these resin films, the substrate is preferably 1 or more selected from the group consisting of a polyester film, a polyamide film, a polyimide film, and a biaxially oriented polypropylene film, more preferably a polyester film, and even more preferably a polyethylene terephthalate film.
The Young's modulus of the substrate is not particularly limited, but is preferably 1000MPa or more, more preferably 1800 to 30000MPa, and further preferably 2500 to 6000MPa.
When the young's modulus of the base material is equal to or higher than the lower limit value, the vibration suppression effect during processing of the workpiece tends to be further improved. When the young's modulus of the base material is not more than the above upper limit, the workability when the base material is attached to a workpiece and the workability when the base material is peeled from the workpiece tend to be good.
The Young's modulus of the substrate can be measured at a test speed of 200 mm/min in accordance with JIS K7127.
The thickness of the substrate is not particularly limited, but is preferably 10 to 200. Mu.m, more preferably 25 to 100. Mu.m, and still more preferably 30 to 70 μm.
When the thickness of the substrate is not less than the lower limit value, sufficient strength for functioning as a support of the pressure-sensitive adhesive sheet tends to be obtained. When the thickness of the base material is equal to or less than the upper limit, appropriate flexibility is obtained, and the workability tends to be improved.
The "thickness of the substrate" refers to the thickness of the entire substrate, and in the case where the substrate is a substrate composed of a plurality of layers, the thickness refers to the total thickness of all the layers constituting the substrate.
The base material may contain a plasticizer, a lubricant, an infrared absorber, an ultraviolet absorber, a filler, a colorant, an antistatic agent, an antioxidant, a catalyst, and the like, within a range not impairing the effects of the present invention.
The substrate may be transparent or opaque, and may be colored or vapor-deposited as necessary.
In view of improving the adhesiveness to other layers, the base material may be subjected to a surface treatment such as corona treatment on at least one surface thereof, or may be provided with a coating layer for the purpose of improving the adhesiveness.
< peel off sheet >
In the pressure-sensitive adhesive sheet of the present embodiment, a release sheet may be attached to at least one of the surface of the pressure-sensitive adhesive layer and the surface of the surface coating layer. The release sheet is releasably attached to the surface of the pressure-sensitive adhesive sheet before use to protect the surface, and is removable when the pressure-sensitive adhesive sheet is used.
The release sheet may be one having undergone a single-side release treatment or one having undergone a double-side release treatment.
The release sheet is preferably a release sheet obtained by applying a release agent to a release sheet substrate.
The substrate for a release sheet is preferably a resin film, and examples of the resin film include: polyester films such as polyethylene terephthalate films, polybutylene terephthalate films, and polyethylene naphthalate films; polyolefin films such as polypropylene films and polyethylene films; and so on.
Examples of the release agent include: rubber elastomers such as silicone resins, olefin resins, isoprene resins, and butadiene resins; long-chain alkyl resins, alkyd resins, fluorine resins, and the like.
The thickness of the release sheet is not particularly limited, but is preferably 5 to 200. Mu.m, more preferably 10 to 100. Mu.m, and still more preferably 20 to 50 μm.
The total thickness of the pressure-sensitive adhesive sheet of the present embodiment is not particularly limited, but is preferably 30 to 300 μm, more preferably 40 to 220 μm, and still more preferably 45 to 160 μm.
When the total thickness of the pressure-sensitive adhesive sheet is not less than the lower limit, the pressure-sensitive adhesive layer can suitably maintain the adhesive performance, the cushion layer impact absorption performance, and the like, and the pressure-sensitive adhesive sheet tends to be able to sufficiently exhibit the function as a pressure-sensitive adhesive sheet for semiconductor processing. When the total thickness of the pressure-sensitive adhesive sheet is equal to or less than the upper limit value, the peeling force when peeling the work from the pressure-sensitive adhesive sheet tends to be reduced.
In the present embodiment, the "total thickness of the pressure-sensitive adhesive sheet" refers to a thickness from the surface of the surface coating layer of the pressure-sensitive adhesive sheet to the surface of the pressure-sensitive adhesive layer, and when a release sheet is provided, the thickness of the release sheet is not included in the total thickness.
< method for producing adhesive sheet >
The method for producing the pressure-sensitive adhesive sheet of the present embodiment is not particularly limited, and can be produced by a known method.
The pressure-sensitive adhesive sheet of the present embodiment can be produced, for example, by a method comprising: the method for producing a pressure-sensitive adhesive sheet includes a step of forming a pressure-sensitive adhesive layer on one surface of a substrate (hereinafter also referred to as "pressure-sensitive adhesive layer forming step"), a step of forming a cushion layer on the other surface of the substrate (hereinafter also referred to as "cushion layer forming step"), and a step of forming a surface coating on the opposite surface of the cushion layer from the substrate (hereinafter also referred to as "surface coating forming step"). The order of these steps is not particularly limited, and when the steps can be performed simultaneously, the steps can be performed simultaneously.
Examples of the method for forming the adhesive layer, the cushion layer, or the surface coating layer include: a method of applying the binder composition, the composition for forming a buffer layer, or the coating liquid for a surface coating layer to a predetermined position by a known method, and then irradiating with an energy ray, heat drying, or the like as necessary.
Examples of the method for applying the binder composition, the composition for forming a buffer layer, or the coating liquid for a surface coating layer include: spin coating, spray coating, bar coating, knife coating, roll coating, blade coating, die coating, gravure coating, and the like.
The pressure-sensitive adhesive layer forming step may be, for example, a method of bonding the pressure-sensitive adhesive layer formed on the release sheet to the surface of the substrate, or a method of directly applying the pressure-sensitive adhesive composition to the surface of the substrate to form the pressure-sensitive adhesive layer.
In the buffer layer forming step, the buffer layer forming composition may be coated on the release sheet or directly coated on the surface of the substrate. In the case of applying the composition for forming a buffer layer to a release sheet, a layer formed of the composition for forming a buffer layer on the release sheet (hereinafter also referred to as "composition layer for forming a buffer layer") is subsequently stuck to the surface of the base material. The buffer layer-forming composition layer on the release sheet may be the buffer layer itself, or when the buffer layer-forming composition has curability, it may be an uncured product or a semi-cured product of the curable buffer layer-forming composition. When an uncured material or a semi-cured material of the composition for forming a buffer layer is formed on a substrate, a treatment for completely curing the composition for forming a buffer layer is subsequently performed.
In the surface coating layer forming step, the coating liquid for surface coating layer may be applied to the release sheet or may be directly applied to the surface of the buffer layer. In the case where the coating liquid for surface coating is coated on the release sheet, a layer formed of the composition for surface coating formation on the release sheet (hereinafter also referred to as "composition layer for surface coating formation") is subsequently stuck to the surface of the buffer layer. The surface coat layer-forming composition layer on the release sheet may be the surface coat itself, or when the surface coat layer-forming composition has curability, it may be an uncured product or a semi-cured product of the surface coat layer-forming composition having curability. When an uncured material or a semi-cured material of the topcoat layer forming composition is formed on the cushion layer, a treatment for completely curing the topcoat layer forming composition is subsequently performed.
The buffer layer forming step and the surface coat layer forming step may be a method of sequentially providing a surface coat layer and a buffer layer on a release sheet and then bonding the buffer layer to the surface of the base material.
When the composition for forming a buffer layer contains an energy ray-polymerizable compound, the buffer layer-forming step preferably includes a step of irradiating the composition for forming a buffer layer with an energy ray.
When the composition for forming a buffer layer contains an energy ray-polymerizable compound, the curing treatment by irradiation with an energy ray may be performed once or in a plurality of times.
In the case where the curing treatment by energy ray irradiation is performed at one time, the composition for forming the buffer layer may be completely cured by energy ray irradiation after the coating film of the composition for forming the buffer layer is formed on the substrate, or the composition for forming the buffer layer may be completely cured on the release sheet and then bonded to the substrate.
When the surface coating layer-forming composition contains an energy ray-polymerizable compound, the surface coating layer-forming step preferably includes a step of irradiating the surface coating layer-forming composition with an energy ray. The time when the energy ray is irradiated to the topcoat layer-forming composition is not particularly limited, and may be any time before or after the topcoat layer-forming composition is laminated on the buffer layer or the buffer layer-forming composition layer.
In the case where the curing treatment of the composition for forming a buffer layer is performed in a plurality of times, the composition for forming a buffer layer may be cured to a semi-cured state and then bonded to the composition layer for forming a surface coating layer provided on the release sheet, after the coating film of the composition for forming a buffer layer is formed on the release sheet, without completely curing the composition for forming a buffer layer on the release sheet, and then the composition for forming a buffer layer may be completely cured by irradiating energy rays again. When the surface coating layer-forming composition contains an energy ray-polymerizable compound, the surface coating layer-forming composition can be simultaneously cured by irradiation with an energy ray for completely curing the buffer layer-forming composition.
The energy ray irradiated in the curing treatment of the composition for forming a buffer layer and the composition for forming a top coat layer is preferably ultraviolet ray.
When the composition for forming a buffer layer and the composition for forming a top coat layer are irradiated with an energy ray and cured, the composition for forming a buffer layer and the composition for forming a top coat layer may be exposed to the outside, but it is preferable that both surfaces are covered with a member such as a release sheet or a substrate and the energy ray is irradiated without being exposed to the outside.
< use of adhesive sheet >
Examples of the processing of the workpiece performed in the state where the adhesive sheet of the present embodiment is attached include: a back grinding process of grinding one surface of the semiconductor device while the other surface is bonded with an adhesive sheet, a dicing process of singulating the semiconductor device with the adhesive sheet bonded to one surface of the semiconductor device, a transportation of the semiconductor device, a pickup of a semiconductor chip, and the like. Among these, the adhesive sheet of the present embodiment is suitable for back grinding, and more particularly suitable for back grinding in which the back surface of a semiconductor wafer is ground with the adhesive sheet of the present embodiment attached to the circuit formation surface of the semiconductor wafer. In particular, the adhesive sheet of the present embodiment has an effect of suppressing the occurrence of cracks when thinning a semiconductor wafer, and is therefore suitable for processes such as the tip dicing method and the stealth tip dicing method.
[ method for manufacturing semiconductor device ]
The method for manufacturing a semiconductor device of the present embodiment includes:
a step of bonding the adhesive sheet for semiconductor processing of the present embodiment to the surface of a semiconductor wafer with the adhesive layer as a bonding surface; and
and grinding the back surface of the semiconductor wafer while the adhesive sheet for semiconductor processing adhered to the semiconductor wafer is held on the surface coating layer side by a holding device.
In addition, the method for manufacturing a semiconductor device according to the present embodiment preferably includes:
a predetermined dividing line forming step a of forming a groove in a front surface of a semiconductor wafer or a step b of forming a modified region from the front surface or the back surface of the semiconductor wafer into the semiconductor wafer;
a sheet sticking step of sticking the adhesive sheet for semiconductor processing of the present embodiment to the surface of the semiconductor wafer with the adhesive layer as a sticking surface after the step a, or before or after the step b; and
and a grinding and singulation step of grinding the back surface of the semiconductor wafer while the surface coating layer side of the adhesive sheet for semiconductor processing, which is adhered to the semiconductor wafer, is fixed by a support device, and singulating the adhesive sheet into a plurality of semiconductor chips with the grooves or the modified regions as starting points.
Further, the method for manufacturing a semiconductor device according to the present embodiment may include, after the grinding and singulation steps:
a peeling step of peeling the adhesive sheet for semiconductor processing according to the present embodiment from the plurality of semiconductor chips.
The method for manufacturing a semiconductor device having the step a is a process corresponding to the dicing technique, and the method for manufacturing a semiconductor device having the step b is a process corresponding to the stealth dicing technique.
Examples of the semiconductor wafer used in the manufacturing method of the present embodiment include: silicon wafers, gallium arsenide wafers, gallium nitride wafers, silicon carbide wafers, glass wafers, sapphire wafers, and the like. Among them, silicon wafers are preferable.
A surface of a semiconductor wafer is generally formed with circuits such as a wiring, a capacitor, a diode, and a transistor. These circuits can be formed by a conventionally known method such as an etching method or a lift-off method.
The thickness of the semiconductor wafer before grinding is not particularly limited, but is usually 500 to 1000 μm.
Hereinafter, each step of the method for manufacturing a semiconductor device according to the present embodiment will be described in detail.
< Process for Forming predetermined dividing line >
The predetermined dividing line forming step is a step a of forming a groove in the front surface of the semiconductor wafer or a step b of forming a modified region from the front surface or the back surface of the semiconductor wafer into the semiconductor wafer.
The step a is a step of forming a groove in the surface of the semiconductor wafer, and may be performed before the adhesive sheet is attached to the surface of the semiconductor wafer.
The grooves formed in the surface of the semiconductor wafer in step a have a depth shallower than the thickness of the semiconductor wafer. After step a, the semiconductor wafer is ground on the back surface to the grooves formed in step a, and is divided into a plurality of semiconductor chips. Therefore, in step a, the grooves are formed along the dividing lines when the semiconductor wafer is divided and singulated into semiconductor chips.
The groove can be formed by dicing using a conventionally known wafer dicing apparatus or the like.
The step b is a step of forming a modified region from the front surface or the back surface of the semiconductor wafer into the semiconductor wafer, and may be performed before or after the adhesive sheet is attached to the front surface of the semiconductor wafer.
In the step b, the modified region is formed inside the semiconductor wafer by irradiating the laser beam focused inside the semiconductor wafer. The modified region is a region where the semiconductor wafer is weakened, and the semiconductor wafer is thinned by back grinding or broken by applying a force by grinding, and becomes a starting point for the singulation of the semiconductor wafer into semiconductor chips. Therefore, the modified region is formed along the dividing line when the semiconductor wafer is divided and singulated into semiconductor chips.
The laser light may be irradiated from the front surface side or the back surface side of the semiconductor wafer. In the case where the step b is performed after the sheet sticking step, the semiconductor wafer may be irradiated with laser light through the adhesive sheet.
< sheet sticking Process >
The sheet bonding step is a step of bonding the adhesive sheet to the surface of the semiconductor wafer with the adhesive layer as a bonding surface after the step a, or before or after the step b.
The method for attaching the adhesive sheet is not particularly limited, and a conventionally known method using a laminator or the like can be used.
< grinding and singulation Process >
The grinding and singulation step is a step of grinding the back surface of the semiconductor wafer while the surface coating layer side of the adhesive sheet attached to the semiconductor wafer is fixed by the support device, thereby singulating the adhesive sheet into a plurality of semiconductor chips starting from the groove or the modified region.
The surface coating side of the adhesive sheet is fixed to the semiconductor wafer to which the adhesive sheet is attached and in which the grooves or modified regions are formed, by a support device. The supporting device is not particularly limited, and is preferably a device that sucks and holds a fixed object such as a chuck table.
Next, the back surface of the fixed semiconductor wafer is ground, and the semiconductor wafer is singulated into a plurality of semiconductor chips.
In the back grinding, when the groove is formed in the semiconductor wafer in the step a, the semiconductor wafer is ground at least until the ground surface reaches the bottom of the groove. The grooves are cut through the wafer by the back grinding, and the semiconductor wafer is divided into individual semiconductor chips by the cuts.
On the other hand, when the modified region is formed in the semiconductor wafer in the step b, the ground surface may reach the modified region, but may not strictly reach the modified region. That is, the semiconductor wafer may be ground to a position close to the modified region so that the semiconductor wafer is broken from the modified region as a starting point and singulated into semiconductor chips. For example, the semiconductor wafer may be diced to a position close to the reformed region without being singulated, and then a pickup tape may be attached to the semiconductor wafer and stretched to be singulated into semiconductor chips.
The shape of the singulated semiconductor chip may be a square shape or an elongated shape such as a rectangular shape.
The thickness of the singulated semiconductor chip is not particularly limited, but is preferably 5 to 100 μm, more preferably 7 to 70 μm, and still more preferably 10 to 45 μm.
The chip size of the singulated semiconductor chip is not particularly limited, but is preferably less than 50mm 2 More preferably less than 30mm 2 Further preferably less than 10mm 2 。
< peeling Process >
The peeling step is a step of peeling the adhesive sheet from the plurality of semiconductor chips after the grinding and singulation steps.
In the case where the adhesive layer of the adhesive sheet is formed of an energy ray-curable adhesive, the adhesive sheet is peeled after the adhesive is cured by irradiation with an energy ray so that the peeling force of the adhesive layer is reduced.
When peeling off the adhesive sheet, a pickup tape may be used. The pickup tape may be, for example, an adhesive sheet including a substrate and an adhesive layer provided on one surface of the substrate.
When the pickup tape is used, first, alignment of position and direction is performed so that the pickup tape can be attached to the back surface side of the singulated semiconductor wafer and picked up. In this case, it is preferable that the pickup tape is attached to the ring frame disposed on the outer peripheral side of the semiconductor wafer, and the outer peripheral edge of the pickup tape is fixed to the ring frame. Next, the adhesive sheet is peeled off from the plurality of semiconductor chips fixed on the pickup tape.
Then, a plurality of semiconductor chips on the pickup tape may be picked up and then fixed on a substrate or the like, thereby manufacturing a semiconductor device.
Examples
The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. The measurement method and evaluation method of various physical properties are as follows.
[ weight average molecular weight (Mw) ]
The weight average molecular weight (Mw) was measured under the following conditions using a gel permeation chromatography apparatus (product name "HLC-8220" available from Tosoh corporation) and was determined in terms of standard polystyrene.
(measurement conditions)
A chromatographic column: "TSK guard column HXL-H", "TSK gel GMHXL (. Times.2)" "TSK gel G2000HXL" (all made by Tosoh Corp.)
Column temperature: 40 deg.C
Elution solvent: tetrahydrofuran (THF)
Flow rate: 1.0mL/min
[ measurement of thickness of adhesive sheet or the like ]
The total thickness of the pressure-sensitive adhesive sheet, the thickness of each layer, and the thickness of the test piece produced therefrom were measured by a constant pressure thickness measuring instrument (product of Lindchoku corporation, trade name "PG-02"). At this time, arbitrary 10 points were measured, and the average value was calculated.
The total thickness of the pressure-sensitive adhesive sheet is a value obtained by measuring the thickness of the pressure-sensitive adhesive sheet with a release sheet and subtracting the thickness of the release sheet from the thickness.
The thickness of the buffer layer is obtained by subtracting the thickness of the base material from the thickness of the base material with the buffer layer.
The thickness of the surface coating is obtained by subtracting the thickness of the release sheet from the thickness of the surface coating with the release sheet.
The thickness of the pressure-sensitive adhesive layer is a value obtained by subtracting the thicknesses of the topcoat layer, the cushion layer, and the substrate from the total thickness of the pressure-sensitive adhesive sheet.
[ measurement of coefficient of static Friction ]
The coefficient of static friction of the surface coating of the adhesive sheet was measured in accordance with JIS K7125, in accordance with the following procedure.
The pressure-sensitive adhesive sheets produced in examples and comparative examples were cut to 63mm × 63mm, and the release sheet on the surface-coating layer side was peeled off to obtain a slide sheet. A weight (mass 1000 g) having a surface having the same shape as that of the slide piece was attached to the adhesive layer of the slide piece with the surface serving as an attachment surface, and then placed on an SUS304#600 steel plate with the surface coating of the slide piece serving as a contact surface. Then, the weight was pulled in the horizontal direction at a speed of 100mm/min, and the static friction coefficient was calculated from the maximum load at the time of pulling. The test was carried out in an environment of 23 ℃ and 50% RH of humidity.
[ measurement of Water contact Angle of surface coating ]
The water contact angle of the surface coating was measured in accordance with JIS R3257. Specifically, the release sheets on the surface coating layer side of the pressure-sensitive adhesive sheets produced in examples and comparative examples were peeled off, and the static contact angle when distilled water was dropped on the exposed surface of the exposed surface coating layer was measured under the following conditions using a full-automatic contact angle measuring instrument (product name "DM-701" manufactured by kyowa interfacial science).
Measurement temperature: 23 deg.C
Amount of distilled water droplets: 2 μ l
Measurement time: after dropping for 1 second
Image analysis method: theta/2 method
[ evaluation of the amount of adhesion of grinding chips to the surface coating ]
The pressure-sensitive adhesive sheets produced in examples and comparative examples were cut into 5cm square pieces, and the release sheet on the surface-coating layer side was peeled off to prepare test pieces with the surface coating exposed. Any 1 of 4 corners of the test piece was fixed and hung, and immersed in grinding water containing 2 mass% of grinding chips of a silicon wafer for 1 minute. The test piece was taken out from the grinding water, left to stand in a suspended state at 23 ℃ for 24 hours to dry, and then the surface coating of the test piece was visually observed to evaluate the amount of adhesion of the grinding chips in accordance with the following criteria. In the following evaluation criteria, the "grinding chip adhering portion" refers to an island-shaped grinding chip adhering portion formed by drying droplets of grinding water adhering to the surface coating layer.
A: there were 1 portion of the surface coating where the grinding chips adhered, or grinding chips that could be recognized as the degree of adhering of the grinding chips did not adhere.
B: the surface coating layer has at least 2 abrasive dust adhering portions.
[ evaluation of transportability ]
The adhesive sheets produced in examples and comparative examples were bonded to a silicon mirror wafer (12 inches in diameter, 50 μm thick, dry polished) with the adhesive layer as the bonding surface, and a silicon mirror wafer with an adhesive sheet (hereinafter also referred to as "adhesive sheet-attached wafer") was produced.
The wafer from which the release sheet was peeled off from the surface coating layer of the wafer with the adhesive sheet was placed on a heating stage so that the surface coating layer was a contact surface, and heated at 80 ℃ for 3 minutes. Then, the suction surface of the transfer arm having the suction surface of the suction mechanism was placed on the surface of the wafer with an adhesive sheet on the side of the silicon mirror surface wafer, and whether or not the wafer with an adhesive sheet could be lifted up from the heating stage was tested in a state where the wafer with an adhesive sheet was sucked and sucked on the suction surface, and the transfer performance was evaluated according to the following criteria.
A: the wafer with the adhesive sheet can be lifted from the heating stage by the transfer arm.
B: the wafer with the adhesive sheet is in close contact with the heating table, and the wafer with the adhesive sheet cannot be lifted up from the heating table by the transfer arm.
[ preparation of urethane acrylate oligomer for buffer layer ]
Production example 1
2-hydroxyethyl acrylate was reacted with an isocyanate terminated urethane prepolymer obtained by reacting a polyester diol with isophorone diisocyanate to obtain a 2-functional urethane acrylate oligomer having a weight average molecular weight (Mw) of 5000.
[ preparation of energy ray-curable acrylic resin used for adhesive layer ]
Production example 2
An acrylic polymer was obtained by copolymerizing 52 parts by mass of n-butyl acrylate, 20 parts by mass of methyl methacrylate, and 28 parts by mass of 2-hydroxyethyl acrylate. Then, 2-methacryloyloxyethyl isocyanate was reacted with 90 mol% of all hydroxyl groups of the acrylic polymer to obtain an energy ray-curable acrylic resin having a weight average molecular weight (Mw) of 50 ten thousand.
[ production of adhesive sheet ]
Examples 1 to 10 and comparative example 1
Next, an adhesive sheet was produced by the following method. In the following description, the total amount of each component added means the amount of the effective component added.
(1) Preparation of the substrate
As a substrate, a polyethylene terephthalate film (Young's modulus: 2500 MPa) having a thickness of 50 μm was prepared.
(2) Preparation of surface coating Forming composition
Each of the components shown in table 1 was dissolved in toluene so that the active ingredient concentration became 10 mass%, to prepare a composition for forming a top coat layer.
(3) Preparation of composition for Forming buffer layer
A composition for forming a buffer layer was prepared by mixing 40 parts by mass of the urethane acrylate oligomer obtained in production example 1, 40 parts by mass of isobornyl acrylate, 20 parts by mass of 2-hydroxy-3-phenoxypropyl acrylate, 2.0 parts by mass of 1-hydroxycyclohexyl phenyl ketone as a photopolymerization initiator, and 0.2 parts by mass of a phthalocyanine pigment.
(4) Preparation of adhesive composition
An adhesive composition was prepared by mixing 100 parts by mass of the energy ray-curable acrylic resin obtained in production example 2, 6 parts by mass of a polyfunctional urethane acrylate (product name "Shikou UT-4332" manufactured by mitsubishi chemical corporation, weight average molecular weight (Mw) 4700) as an energy ray-curable compound, 0.375 part by mass of an isocyanate-based crosslinking agent (product name "CORONATE L" manufactured by tokyo co., ltd.), and 1 part by mass of phenyl bis (2, 4, 6-trimethylbenzoyl) phosphine oxide as a photopolymerization initiator, and diluting the mixture with an organic solvent.
(5) Production of adhesive sheet
The composition for forming a buffer layer obtained above was applied to one surface of the substrate described above so that the thickness of the buffer layer formed was 13 μm, and then the resultant was irradiated at an illuminance of 30mW/cm 2 And an irradiation dose of 60mJ/cm 2 By irradiating ultraviolet rays under the conditions of (1), the composition for forming a buffer layer is semi-cured, and the composition for forming a buffer layer is formed on one surface of the substrate in a semi-cured stateAnd (3) a layer formed by chemical conversion.
The surface coating layer-forming composition obtained above was applied to the release-treated surface of a release sheet (product name "SP-PET381031" manufactured by ledebacae) using a mayer rod so that the thickness after drying was 2 μm, and then heated and dried to produce a release sheet-attached surface coating layer.
The surface coating layer with the surface coating layer of the release sheet was bonded to a layer formed on one surface of the base material and obtained by semi-curing the composition for forming the buffer layer, and then the illuminance was 160mW/cm 2 The dose of irradiation was 500mJ/cm 2 The composition for forming a buffer layer and the composition for forming a top coat layer were cured by irradiation with ultraviolet rays under the conditions of (1), and a laminate having the buffer layer and the top coat layer in this order on one surface of the substrate was obtained.
The pressure-sensitive adhesive composition obtained above was applied to a release-treated surface of a release sheet (product of Lindeke corporation, trade name "SP-PET 381031") so that the thickness after drying was 20 μm, and then heat-dried to prepare a release sheet with a pressure-sensitive adhesive layer.
The pressure-sensitive adhesive layer of the pressure-sensitive adhesive layer-attached release sheet is bonded to the side of the substrate of the laminate on which the cushion layer is not provided, thereby obtaining a pressure-sensitive adhesive sheet having a surface coating layer, a cushion layer, a substrate, and a pressure-sensitive adhesive layer in this order.
The evaluation results of the pressure-sensitive adhesive sheets obtained in examples and comparative examples are shown in table 1.
[ Table 1]
Figure BDA0003866518650000401
H1043: hydrogenated styrenic thermoplastic elastomer (SEBS), styrene content: 67% by mass of a product name "Tuftec (registered trademark) H1043" available from Asahi Kasei Co., ltd "
PMA-L: propylene-butene-maleic anhydride copolymer, maleic anhydride modification ratio: 1.5 mass%, weight average molecular weight (Mw): 75000. toyo Boseki Kabushiki Kaisha "TOYO-TAC (registered trademark) PMA-L"
X-22-164B: a polydimethylsiloxane compound having methacryloxy groups at both ends, a weight average molecular weight (Mw): 5000. trade name "X-22-164B" manufactured by shin-Etsu chemical Co., ltd "
X-22-164E: a polydimethylsiloxane compound having methacryloxy groups at both ends, a weight average molecular weight (Mw): 13000. trade name "X-22-164E" manufactured by shin-Etsu chemical Co., ltd "
Energy ray-polymerizable polyfunctional compound: mixture of dipentaerythritol hexaacrylate and dipentaerythritol pentaacrylate, manufactured by Nippon Kayarad DPHA "
Photopolymerization initiator: 2-hydroxy-2-methyl-1-phenylpropanone, product name "Omnirad1173" manufactured by IGM Resins B.V.
As is clear from table 1, the adhesive sheets of examples 1 to 10 having a surface coating layer with a coefficient of static friction of 0.70 or less were excellent in handling property and sufficiently reduced in the amount of adhered grinding swarf. On the other hand, the pressure-sensitive adhesive sheet of comparative example 1 having a surface coating layer with a static friction coefficient exceeding 0.70 was inferior in transportability, and had a larger amount of adhered grinding chips than the pressure-sensitive adhesive sheets of examples 1 to 10.

Claims (11)

1. An adhesive sheet for semiconductor processing, which comprises a surface coating layer, a cushion layer, a substrate and an adhesive layer in this order,
the surface coating has a static friction coefficient of 0.70 or less with respect to SUS 304.
2. The adhesive sheet for semiconductor processing according to claim 1, wherein,
the surface coating layer is a layer formed from a surface coating layer-forming composition containing a resin component and a slip property-improving component.
3. The adhesive sheet for semiconductor processing according to claim 2, wherein,
the resin component has a heteroatom content of 7 mass% or less.
4. The adhesive sheet for semiconductor processing according to claim 2 or 3, wherein,
the content of the resin component in the surface coating layer-forming composition is 50 to 99 mass% with respect to the total amount (100 mass%) of the active components of the surface coating layer-forming composition.
5. The adhesive sheet for semiconductor processing according to any one of claims 2 to 4, wherein,
the sliding property improving component has a heteroatom content of 30 mass% or more.
6. The adhesive sheet for semiconductor processing according to any one of claims 2 to 5, wherein,
the content of the sliding property improving component in the surface coating layer forming composition is 0.1 to 30% by mass relative to the total amount (100% by mass) of the active components in the surface coating layer forming composition.
7. The adhesive sheet for semiconductor processing according to any one of claims 1 to 6, wherein,
the thickness of the surface coating is 0.05-10 μm.
8. The adhesive sheet for semiconductor processing according to any one of claims 1 to 7,
the buffer layer is formed from a buffer layer-forming composition containing a urethane (meth) acrylate.
9. The adhesive sheet for semiconductor processing according to any one of claims 1 to 8, which is used for back grinding of a semiconductor wafer.
10. A method of manufacturing a semiconductor device, the method comprising:
a step of bonding the adhesive sheet for semiconductor processing according to any one of claims 1 to 9 to a surface of a semiconductor wafer with the adhesive layer as a bonding surface; and
and grinding the back surface of the semiconductor wafer while the front surface coating layer side of the adhesive sheet for semiconductor processing attached to the semiconductor wafer is fixed by a supporting device.
11. The method for manufacturing a semiconductor device according to claim 10, the method comprising:
a predetermined dividing line forming step a of forming a groove in a front surface of a semiconductor wafer or a step b of forming a modified region from the front surface or the back surface of the semiconductor wafer into the semiconductor wafer;
a sheet sticking step of sticking the adhesive sheet for semiconductor processing according to any one of claims 1 to 9 to the surface of the semiconductor wafer with the adhesive layer as a sticking surface after the step a or before or after the step b; and
and a grinding and singulation step of grinding the back surface of the semiconductor wafer while the front surface coating layer side of the adhesive sheet for semiconductor processing, which is adhered to the semiconductor wafer, is fixed by a support device, and singulating the adhesive sheet into a plurality of semiconductor chips with the grooves or the modified regions as starting points.
CN202211184038.XA 2021-09-27 2022-09-27 Adhesive sheet for semiconductor processing and method for manufacturing semiconductor device Pending CN115873525A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2021156971 2021-09-27
JP2021-156971 2021-09-27

Publications (1)

Publication Number Publication Date
CN115873525A true CN115873525A (en) 2023-03-31

Family

ID=85770097

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202211184038.XA Pending CN115873525A (en) 2021-09-27 2022-09-27 Adhesive sheet for semiconductor processing and method for manufacturing semiconductor device

Country Status (4)

Country Link
JP (1) JP2023048104A (en)
KR (1) KR20230044939A (en)
CN (1) CN115873525A (en)
TW (1) TW202317720A (en)

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2015056446A (en) 2013-09-10 2015-03-23 古河電気工業株式会社 Adhesive tape for protection of semiconductor wafer surface and method for processing semiconductor wafer

Also Published As

Publication number Publication date
JP2023048104A (en) 2023-04-06
KR20230044939A (en) 2023-04-04
TW202317720A (en) 2023-05-01

Similar Documents

Publication Publication Date Title
JP7207778B2 (en) Adhesive tape for semiconductor processing and method for manufacturing semiconductor device
CN109743877B (en) Adhesive tape for semiconductor processing and method for manufacturing semiconductor device
CN112334558B (en) Adhesive tape for semiconductor processing and method for manufacturing semiconductor device
TW202016234A (en) Semiconductor processing adhesive tape and method of manufacturing semiconductor device
WO2012128312A1 (en) Base film and pressure-sensitive adhesive sheet provided therewith
JPWO2019181730A1 (en) Manufacturing method of adhesive tape and semiconductor device
WO2019181732A1 (en) Adhesive tape, and method for producing semiconductor device
WO2019155970A1 (en) Adhesive tape for semiconductor fabrication
CN115873525A (en) Adhesive sheet for semiconductor processing and method for manufacturing semiconductor device
CN115873524A (en) Adhesive sheet for semiconductor processing, method for producing same, and method for producing semiconductor device
TW202137305A (en) Protection sheet for semiconductor processing and manufacturing method of semiconductor device fully following the unevenness of the wafer even when a semiconductor wafer having unevenness is thinned by DBG, etc.
TW202137306A (en) Protection sheet for semiconductor processing and manufacturing method of semiconductor device can suppress the generation of cracks in the wafer after polishing
WO2018168403A1 (en) Base material for back grinding tape
CN116918039A (en) Adhesive sheet for semiconductor processing and method for manufacturing semiconductor device
CN116918038A (en) Adhesive sheet for semiconductor processing and method for manufacturing semiconductor device
CN117645844A (en) Adhesive sheet for semiconductor processing and method for manufacturing semiconductor device
CN117645845A (en) Adhesive sheet for semiconductor processing and method for manufacturing semiconductor device
JP2024035418A (en) Adhesive sheet for semiconductor processing and method for manufacturing semiconductor devices
KR20240032655A (en) Adhesive sheet for semiconductor processing and method of manufacturing semiconductor device
JP2024035414A (en) Adhesive sheet for semiconductor processing and method for manufacturing semiconductor devices
JP2024035411A (en) Adhesive sheet for semiconductor processing and method for manufacturing semiconductor devices
KR20240032654A (en) Adhesive sheet for semiconductor processing and method of manufacturing semiconductor device
CN116941017A (en) Adhesive tape for semiconductor processing and method for manufacturing semiconductor device
CN117099185A (en) Adhesive tape for semiconductor processing and method for manufacturing semiconductor device

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication