CN117157369A - Adhesive tape for processing workpiece - Google Patents

Adhesive tape for processing workpiece Download PDF

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Publication number
CN117157369A
CN117157369A CN202280025102.1A CN202280025102A CN117157369A CN 117157369 A CN117157369 A CN 117157369A CN 202280025102 A CN202280025102 A CN 202280025102A CN 117157369 A CN117157369 A CN 117157369A
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CN
China
Prior art keywords
meth
acrylate
mass
copolymer
adhesive tape
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Pending
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CN202280025102.1A
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Chinese (zh)
Inventor
斋藤邦生
守本宗弘
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Maxell Ltd
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Maxell Ltd
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    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J7/00—Adhesives in the form of films or foils
    • C09J7/30—Adhesives in the form of films or foils characterised by the adhesive composition
    • C09J7/38—Pressure-sensitive adhesives [PSA]
    • C09J7/381—Pressure-sensitive adhesives [PSA] based on macromolecular compounds obtained by reactions involving only carbon-to-carbon unsaturated bonds
    • C09J7/385—Acrylic polymers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B32B27/30—Layered products comprising a layer of synthetic resin comprising vinyl (co)polymers; comprising acrylic (co)polymers
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F220/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride ester, amide, imide or nitrile thereof
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J133/00—Adhesives based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides, or nitriles thereof; Adhesives based on derivatives of such polymers
    • C09J133/02—Homopolymers or copolymers of acids; Metal or ammonium salts thereof
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J133/00—Adhesives based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides, or nitriles thereof; Adhesives based on derivatives of such polymers
    • C09J133/04—Homopolymers or copolymers of esters
    • C09J133/06—Homopolymers or copolymers of esters of esters containing only carbon, hydrogen and oxygen, the oxygen atom being present only as part of the carboxyl radical
    • C09J133/08—Homopolymers or copolymers of acrylic acid esters
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J133/00—Adhesives based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides, or nitriles thereof; Adhesives based on derivatives of such polymers
    • C09J133/04—Homopolymers or copolymers of esters
    • C09J133/06—Homopolymers or copolymers of esters of esters containing only carbon, hydrogen and oxygen, the oxygen atom being present only as part of the carboxyl radical
    • C09J133/10—Homopolymers or copolymers of methacrylic acid esters
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J133/00—Adhesives based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides, or nitriles thereof; Adhesives based on derivatives of such polymers
    • C09J133/04—Homopolymers or copolymers of esters
    • C09J133/14—Homopolymers or copolymers of esters of esters containing halogen, nitrogen, sulfur or oxygen atoms in addition to the carboxy oxygen
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J7/00—Adhesives in the form of films or foils
    • C09J7/20—Adhesives in the form of films or foils characterised by their carriers
    • C09J7/22—Plastics; Metallised plastics
    • C09J7/25—Plastics; Metallised plastics based on macromolecular compounds obtained otherwise than by reactions involving only carbon-to-carbon unsaturated bonds
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J7/00—Adhesives in the form of films or foils
    • C09J7/20—Adhesives in the form of films or foils characterised by their carriers
    • C09J7/22—Plastics; Metallised plastics
    • C09J7/25—Plastics; Metallised plastics based on macromolecular compounds obtained otherwise than by reactions involving only carbon-to-carbon unsaturated bonds
    • C09J7/255—Polyesters
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J7/00—Adhesives in the form of films or foils
    • C09J7/30—Adhesives in the form of films or foils characterised by the adhesive composition
    • C09J7/38—Pressure-sensitive adhesives [PSA]
    • 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
    • C09J7/50—Adhesives in the form of films or foils characterised by a primer layer between the carrier and the adhesive
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/67—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere
    • H01L21/683—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere for supporting or gripping
    • H01L21/6835—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere for supporting or gripping using temporarily an auxiliary support
    • H01L21/6836—Wafer tapes, e.g. grinding or dicing support tapes
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J2203/00—Applications of adhesives in processes or use of adhesives in the form of films or foils
    • C09J2203/326—Applications of adhesives in processes or use of adhesives in the form of films or foils for bonding electronic components such as wafers, chips or semiconductors
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J2301/00—Additional features of adhesives in the form of films or foils
    • C09J2301/40—Additional features of adhesives in the form of films or foils characterized by the presence of essential components
    • C09J2301/416—Additional features of adhesives in the form of films or foils characterized by the presence of essential components use of irradiation
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J2433/00—Presence of (meth)acrylic polymer
    • C09J2433/003—Presence of (meth)acrylic polymer in the primer coating

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Engineering & Computer Science (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Computer Hardware Design (AREA)
  • Physics & Mathematics (AREA)
  • Power Engineering (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • General Physics & Mathematics (AREA)
  • Manufacturing & Machinery (AREA)
  • Polymers & Plastics (AREA)
  • Health & Medical Sciences (AREA)
  • Medicinal Chemistry (AREA)
  • Adhesive Tapes (AREA)
  • Adhesives Or Adhesive Processes (AREA)
  • Mechanical Treatment Of Semiconductor (AREA)
  • Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)
  • Laminated Bodies (AREA)

Abstract

The invention provides an adhesive tape for processing a workpiece, which can be used as a back surface grinding tape for grinding and thinning a semiconductor wafer and can also be used as a dicing tape for cutting a brittle workpiece such as a glass substrate. More specifically, the adhesive tape for processing a workpiece according to the present invention comprises, in order, a base film formed from a polyester resin composition, an intermediate layer formed from a resin composition containing a (meth) acrylate copolymer (A1) containing methyl acrylate and methacrylic acid as copolymer monomer components, and an active energy ray-curable adhesive layer formed from an adhesive composition containing, when the total amount of the copolymer monomer components constituting the acrylic copolymer (A1) is 100 parts by mass, methyl acrylate in the range of 47 to 67 parts by mass and methacrylic acid in the range of 2 to 7 parts by mass, and the adhesive tape comprises: a (meth) acrylate copolymer (A2) having a photosensitive carbon-carbon double bond introduced into a side chain of a (meth) acrylate copolymer base polymer containing n-butyl acrylate as a main component of a copolymer monomer, and a crosslinking agent.

Description

Adhesive tape for processing workpiece
Technical Field
The present invention relates to an adhesive tape for processing a workpiece, which can be suitably used in processing a workpiece such as a semiconductor wafer or a glass substrate.
Background
Conventionally, as a step of manufacturing a semiconductor chip of a semiconductor device, a back grinding (hereinafter, sometimes simply referred to as "grinding") step of thinning a semiconductor wafer by grinding the semiconductor wafer having a circuit formed on a surface thereof by a grinding wheel to a predetermined thickness, and a dicing step (hereinafter, sometimes simply referred to as "dicing" or "cutting") of singulating the semiconductor wafer into semiconductor chips have been known. In addition, for example, as a step of manufacturing a camera module for a smart phone, a medical sensor, and the like, a dicing step for singulating a glass substrate into glass chips is known. Examples of the adhesive tape used for polishing or cutting such a workpiece such as a semiconductor wafer or a glass plate include an adhesive tape for processing a workpiece such as a back surface polishing tape or a dicing tape, which has an active energy ray-curable adhesive layer on a base film.
The back surface grinding tape is used for stably holding and fixing the semiconductor wafer in the back surface grinding process and protecting the circuit surface. Specific methods of use are described below. First, a back surface polishing tape is attached to a surface side of a semiconductor wafer on which a circuit is formed, and the semiconductor wafer is fixed, and the back surface side of the semiconductor wafer is polished to a predetermined thickness by spraying water using a polishing wheel. After the polishing step is completed, the adhesive layer of the back surface polishing tape is irradiated with active energy rays such as ultraviolet rays (UV) to reduce the adhesive force, and the back surface polishing tape is peeled from the semiconductor wafer.
The dicing tape is used to fix the thinned semiconductor wafer so as not to shift in position and to prevent the singulated semiconductor chips from scattering when the thinned semiconductor wafer is singulated into individual semiconductor chips by cutting the thinned semiconductor wafer by grinding in the back grinding step into a predetermined size, for example, by a rotating dicing blade. Specific methods of use are described below. First, after the dicing tape is attached to the ring frame, a thinned semiconductor wafer is attached to and placed on the adhesive layer. Next, cutting processing is performed so as to singulate the semiconductor wafer into a predetermined size while supplying running water to a dicing blade and the semiconductor wafer for the purpose of removing the chips and the like inevitably generated. After the dicing step is completed, the adhesive layer of the dicing tape is irradiated with active energy rays such as ultraviolet rays (UV) to reduce the adhesive force, and the singulated semiconductor chips are picked up from the adhesive layer by a pickup device. Before picking up, the dicing tape is expanded (dilated) as needed. If the pick-up is over, the dicing tape is peeled off the ring frame by a person. The ring frame from which the dicing tape was peeled was washed and reused.
In recent years, with the thinning of semiconductor devices, further thinning of semiconductor wafers has been demanded in the back grinding step. In order to grind a semiconductor wafer to a thickness smaller than the conventional one, a back surface grinding tape having a thickness accuracy higher than the conventional one is required. That is, if the back surface polishing tape is uneven in thickness, the uneven thickness may affect the semiconductor wafer, and the thickness of the polished semiconductor wafer may become uneven or, at worst, the semiconductor wafer may be damaged. In order to improve the thickness accuracy of the back surface polishing tape, a polyester film such as a polyethylene terephthalate film having high thickness accuracy is preferably used as the base film (patent document 1).
In the dicing step, unlike the case of a semiconductor wafer, for example, a dicing tape having less deformation than in the conventional dicing is required in order to dice a brittle and easily broken workpiece such as a glass substrate, a hard workpiece such as sapphire glass or a crystal substrate. That is, if the deformation of the dicing tape at the time of dicing is large, the glass substrate cannot withstand the deformation thereof and is cracked, and chipping (chipping) or chip splashing occurs (end portion of glass chip, cutting surface chipping) and there is a problem in quality of the glass substrate fragments to be cut. In addition, when cutting a hard sapphire glass substrate, there are cases where: the chip position shift occurs, and defects caused by collision of chips and pick-up errors of chips occur; the dimensional accuracy of the chip is deteriorated. In order to suppress deformation of the dicing tape, a polyester film such as a relatively hard polyethylene terephthalate film having a large tensile elastic modulus is preferably used as the base film (patent document 2).
However, from the viewpoint of a user using the adhesive tape for processing a workpiece as described above, there is a demand that the types of adhesive tapes for processing a workpiece should not be increased as much as possible, for example, for the purpose of avoiding erroneous feeding of the adhesive tape used in each step, for the purpose of improving production efficiency, or the like. That is, there is a demand for an adhesive tape for workpiece processing that can be used as a back surface polishing tape that can be used for polishing and thinning a semiconductor wafer, and can also be used as a dicing tape that can be used for cutting a brittle workpiece such as a glass substrate. In addition, from the viewpoint of manufacturers of adhesive tapes for manufacturing work pieces, an adhesive tape having such a function is desired in order to improve production efficiency. However, it is difficult to satisfy the characteristics required in each step at the same time for the reasons described below, and it is difficult to achieve the characteristics.
In order to realize such an adhesive tape for work processing that can be used in both a back grinding step for thinning a semiconductor wafer and a dicing step for a brittle and easily broken glass substrate or the like, as described above, a polyester film such as a polyethylene terephthalate film is preferably used at least as a base film. However, when the back surface polishing tape or dicing tape is produced by directly laminating the active energy ray-curable adhesive layer on the polyester film, the adhesion between the base film and the active energy ray-curable adhesive layer may be insufficient as compared with the conventional back surface polishing tape or dicing tape using a relatively soft and stretchable base film such as a polyolefin film. That is, the active energy ray-curable adhesive layer has an advantage that it is polymerized and cured three-dimensionally by irradiation with active energy rays, and volume shrinkage occurs from a normal state before curing, and the elastic modulus also increases. Further, by utilizing this phenomenon, the work such as a semiconductor wafer and a glass chip can be easily peeled from the adhesive layer. However, since the polyolefin film which is relatively soft and has stretchability can follow the volume shrinkage of the adhesive layer to some extent, the adhesion between the active energy ray-curable adhesive and the polyolefin film is maintained, but the surface smoothness is high, and in the rigid polyester film, it is difficult to follow the volume shrinkage of the adhesive layer, and therefore the adhesion between the active energy ray-curable adhesive layer and the polyester film may be reduced. As a result, for example, when the active energy ray-curable adhesive is peeled from the semiconductor wafer, the active energy ray-curable adhesive may peel from the polyester film interface, and the active energy ray-curable adhesive may be transferred to the surface of the semiconductor wafer.
Patent document 1 discloses an adhesive sheet in which a polyester base film, a tie coat layer containing a compound having an energy ray polymerizable group, and an energy ray curable adhesive layer are laminated in this order, even when a polyester film is used as a base material of the energy ray curable adhesive sheet, in order to provide an adhesive sheet in which the energy ray curable adhesive layer is not transferred to a wafer or the like. It is presumed that, at the time of curing the energy ray-curable adhesive, at least a part of the energy ray-polymerizable groups contained in the anchor coat layer are also polymerized at the same time, and covalent bonds are formed between a part of the adhesive layer and the anchor coat layer, so that the adhesive layer and the substrate can be kept in close contact by the anchor coat layer.
The adhesive sheet described in patent document 1 is specifically an adhesive sheet for protecting a circuit surface of a semiconductor wafer when polishing a back surface of the semiconductor wafer. The adhesive sheet can be used for temporarily fixing a wafer even in a dicing step of a semiconductor wafer, but when the adhesive sheet is used as a dicing tape for a glass substrate, a sapphire glass substrate, or the like, the following problems may occur. In general, a dicing tape is supplied to a dicing step in a state of being stuck to a ring frame. In the dicing step, in order to cool frictional heat generated between the dicing blade rotating at a high speed and the glass substrate or the sapphire glass substrate, and in order to remove the dicing scraps, washing water is sprayed, but it is necessary to firmly adhere the dicing tape to the ring frame so as to be able to withstand the load and the water pressure thereof. In addition, the dicing tape is sometimes expanded as needed, and therefore, at this time, it is also necessary to firmly adhere the dicing tape so as not to peel off from the ring frame. In the case of a dicing tape having an active energy ray-curable adhesive layer, since the adhesive force of the portion irradiated with active energy rays is reduced, the adhesive layer adhered to the portion of the ring frame (adhesive paste portion) is usually maintained at a high adhesive force without irradiation with active energy rays. In this way, when the adhesive sheet described in patent document 1 is adhered to the ring frame and the adhesive paste portion is supplied to the dicing step without irradiation of active energy rays, there is a possibility that the adhesion force of the interface between the anchor coat layer and the energy ray-curable adhesive layer becomes insufficient, and there is a possibility that the adhesive sheet is peeled off from the ring frame in the dicing step, and there is a possibility that the adhesive layer is transferred (paste remains) to the ring frame when an unnecessary dicing tape is peeled off from the ring frame after the necessary step. As a result, the number of times of washing for removing the adhesive from the ring frame increases, and the life of the ring frame may be shortened. Further, such problems are not described.
Patent document 2 discloses an adhesive sheet for cutting a glass substrate, which is provided with an adhesive layer having a thickness of 9 μm or less on a base film having a thickness of 130 μm or more and a tensile elastic modulus of 1GPa or more, in order to provide an adhesive sheet for cutting a glass substrate, which has excellent shape properties and is hardly broken or scattered chips. In the examples, an ultraviolet curable adhesive sheet having an ultraviolet curable adhesive layer formed thereon was exemplified by using a polyester film (tensile elastic modulus 1.5 GPa) having one surface subjected to corona treatment as a base film.
The adhesive sheet of patent document 2 is an adhesive sheet for cutting a glass substrate, but there is no description about the paste residue of the ring frame, and as described above, when an unnecessary dicing tape is peeled from the ring frame after the dicing step, it is not clear whether or not the adhesive layer is transferred (paste residue) to the ring frame, and there is a concern about the paste residue. In addition, when the adhesive sheet of patent document 2 is used as a back surface polishing tape for a semiconductor wafer, the following problems may occur. That is, when the back surface polishing tape is peeled after the required process, there is a problem that the surface is uneven due to the formation of a circuit and the entire surface of the semiconductor wafer is peeled from the large area, and therefore, the load applied to the interface between the base film and the ultraviolet curable adhesive layer is large, and the ultraviolet curable adhesive layer is peeled from the base film at the interface, and there is a concern that the ultraviolet curable adhesive may be transferred to the surface of the semiconductor wafer. Further, in the adhesive sheet of patent document 2, the thickness of the adhesive agent is relatively small, and it is difficult to follow the circuit formed on the surface of the semiconductor wafer, and sufficient protection cannot be performed, so that polishing water may intrude into the interface between the semiconductor wafer and the adhesive agent layer during polishing. Further, when active energy rays are irradiated after polishing, the ultraviolet curable adhesive layer is susceptible to oxygen inhibition, and the ultraviolet curable adhesive layer cannot be sufficiently cured, and when an unnecessary back surface polishing tape is peeled off from the entire surface of the semiconductor wafer, there is a concern that the paste remains on the peripheral edge portion of the circuit surface.
As described above, in order to realize an adhesive tape for workpiece processing that can be used as a back surface polishing tape that can be used for polishing and thinning a semiconductor wafer and that can be used as a dicing tape that can be used for cutting a brittle workpiece such as a glass substrate or a hard workpiece such as a sapphire glass substrate, it is necessary to sufficiently adhere a polyester film as a base film to an active energy ray-curable adhesive layer at least before and after irradiation with active energy rays, but such adhesive tapes for workpiece processing have not been found in the present situation.
Prior art literature
Patent literature
Patent document 1: japanese patent application laid-open No. 2013-23665
Patent document 2: japanese patent application laid-open No. 2004-10829
Disclosure of Invention
Problems to be solved by the invention
The present invention has been made in view of the above-described problems and circumstances, and an object of the present invention is to provide an adhesive tape for work processing, which is capable of peeling an active energy ray-curable adhesive layer without being transferred to a semiconductor wafer at the time of peeling, and which is sufficiently large in adhesion between a base film and an active energy ray-curable adhesive both before and after irradiation with active energy rays even when used as a back surface polishing tape for thinning a semiconductor wafer, and which is capable of peeling without leaving a paste residue at the time of peeling even when used as a dicing tape for cutting a brittle work such as a glass substrate or a hard work such as a sapphire glass substrate in a process. That is, an object of the present invention is to provide an adhesive tape for work processing which can be used as a back surface polishing tape for polishing and thinning a semiconductor wafer and also as a dicing tape for cutting a brittle work such as a glass substrate or a hard work such as a sapphire glass substrate.
Means for solving the problems
That is, the adhesive tape for processing a workpiece of the present invention is characterized by comprising, in order, a base film formed of a polyester resin composition, an intermediate layer, and an active energy ray-curable adhesive layer,
the intermediate layer is formed from a resin composition containing a ternary or higher (meth) acrylate copolymer (A1) comprising Methyl Acrylate (MA) and methacrylic acid (MAA) as copolymer monomer components,
when the total amount of the monomer components constituting the ternary or higher (meth) acrylate copolymer (A1) is 100 parts by mass, the Methyl Acrylate (MA) is contained in a range of 47 to 67 parts by mass, the methacrylic acid (MAA) is contained in a range of 2 to 7 parts by mass,
the active energy ray-curable adhesive layer is formed from an adhesive composition containing: a (meth) acrylate copolymer (A2) having a photosensitive carbon-carbon double bond introduced into a side chain of a binary or higher (meth) acrylate copolymer Base Polymer (BP) and a crosslinking agent,
the binary or higher (meth) acrylate copolymer Base Polymer (BP) contains n-butyl acrylate (n-BA) as a copolymer monomer component in a proportion of more than 50 parts by mass and 90 parts by mass or less, based on 100 parts by mass of the total amount of copolymer monomer components constituting the (meth) acrylate copolymer Base Polymer (BP).
In one embodiment, the ternary or higher (meth) acrylate copolymer (A1) is a ternary or higher (meth) acrylate copolymer containing 2-ethylhexyl acrylate (2-EHA) as a copolymer monomer component other than the Methyl Acrylate (MA) and the methacrylic acid (MAA).
In one embodiment, the ternary or higher (meth) acrylate copolymer (A1) is a ternary (meth) acrylate copolymer in which the 2-ethylhexyl acrylate (2-EHA), methyl Acrylate (MA) and methacrylic acid (MAA) are used as the copolymer monomer components, and the 2-ethylhexyl acrylate (2-EHA) is contained in a range of 26 to 51 parts by mass, the Methyl Acrylate (MA) is contained in a range of 47 to 67 parts by mass, and the methacrylic acid (MAA) is contained in a range of 2 to 7 parts by mass, so that the total amount of the copolymer monomer components is adjusted to 100 parts by mass, based on 100 parts by mass of the total amount of the copolymer monomer components constituting the ternary (meth) acrylate copolymer.
In one embodiment, the glass transition temperature (Tg) of the ternary or higher (meth) acrylate copolymer (A1) is in the range of-36℃to-9 ℃.
In one embodiment, the binary or higher (meth) acrylate copolymer Base Polymer (BP) is a ternary (meth) acrylate copolymer containing n-butyl acrylate (n-BA), 2-hydroxyethyl acrylate (2-HEA) and methacrylic acid (MAA) as copolymer monomer components, and the n-butyl acrylate (n-BA) is contained in a range of 66 parts by mass to 90 parts by mass, the 2-hydroxyethyl acrylate (2-HEA) is contained in a range of 9.8 parts by mass to 31 parts by mass, and the methacrylic acid (MAA) is contained in a range of 0.2 parts by mass to 3 parts by mass so that the total amount of the copolymer monomer components becomes 100 parts by mass, based on 100 parts by mass of the total amount of the copolymer monomer components constituting the (meth) acrylate copolymer Base Polymer (BP).
In one embodiment, the binary or higher (meth) acrylate copolymer Base Polymer (BP) has a glass transition temperature (Tg) in the range of-50 ℃ to-39 ℃.
In one embodiment, the thickness of the intermediate layer is 5 μm or more.
In one embodiment, the active energy ray-curable adhesive layer has a thickness of 5 μm or more.
In one embodiment, the sum of the thickness of the intermediate layer and the thickness of the active energy ray-curable adhesive layer is 10 μm or more.
In one embodiment, the base film formed of the polyester resin composition is a polyethylene terephthalate film.
In one embodiment, the adhesive force of the adhesive tape for processing a workpiece before ultraviolet irradiation to a glass plate is in a range of 5.0N/25mm to 25.0N/25mm, and the adhesive force after ultraviolet irradiation is in a range of 0.01N/25mm to 0.50N/25 mm.
In one embodiment, the adhesive tape for processing a workpiece has an adhesive force to a stainless steel plate (SUS 304BA plate) before ultraviolet irradiation of 5.0N/25mm to 25.0N/25mm, and an adhesive force after ultraviolet irradiation of 0.01N/25mm to 0.50N/25 mm.
ADVANTAGEOUS EFFECTS OF INVENTION
According to the present invention, it is possible to provide an adhesive tape for work processing, which is capable of peeling an active energy ray-curable adhesive layer without being transferred to a semiconductor wafer at the time of peeling, and of peeling from a ring frame without leaving a paste residue at the time of peeling, even when the adhesive tape is used as a back surface grinding tape for thinning a semiconductor wafer, even when the adhesive tape is used as a dicing tape for cutting a brittle work such as a glass substrate, a hard work such as a sapphire glass substrate, or the like, and the adhesion between the substrate film and the active energy ray-curable adhesive is sufficiently large both before and after the active energy ray irradiation when the adhesive tape is used as the substrate film and the active energy ray-curable adhesive layer is used as the adhesive layer. That is, it is possible to provide an adhesive tape for work processing which can be used as a back surface grinding tape capable of coping with grinding and thinning of a semiconductor wafer and as a dicing tape capable of coping with cutting of a brittle work such as a glass substrate.
Drawings
Fig. 1 is a cross-sectional view showing an example of a structure of an adhesive tape for processing a workpiece to which the present embodiment is applied.
Fig. 2 is a cross-sectional view showing an example of another embodiment of a structure of an adhesive tape for processing a workpiece to which the present embodiment is applied.
Fig. 3 is a perspective view showing a state in which a ring frame (wafer ring) is bonded and held from above to the outer edge portion of the adhesive tape for workpiece processing to which the present embodiment is applied, and a glass substrate singulated by a dicing process is bonded and held to the center portion of the adhesive tape for workpiece processing.
Fig. 4 is a schematic cross-sectional view showing a mode of using the adhesive tape for workpiece processing to which the present embodiment is applied in a dicing step.
Fig. 5 is a perspective view showing a state in which the adhesive tape for workpiece processing to which the present embodiment is applied is peeled from the ring frame from below.
Fig. 6 is a schematic cross-sectional view showing a mode of using the adhesive tape for workpiece processing to which the present embodiment is applied in the back grinding step: (a) before milling; (b) after thinning.
Fig. 7 is a schematic view showing a step of peeling the adhesive tape for work processing according to the embodiment from the surface of the thinned semiconductor wafer with the peeling tape as a starting point: (a) a cross-sectional view before peeling; (b) a perspective view showing a state in the middle of separation from the upper surface.
Detailed Description
Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings as necessary. However, the present invention is not limited to the following embodiments.
Structure of adhesive tape for workpiece processing
Fig. 1 is a cross-sectional view showing an example of a structure of an adhesive tape for processing a workpiece to which the present embodiment is applied. As shown in fig. 1, the adhesive tape 10 for work processing has a structure in which an intermediate layer 2 and an active energy ray-curable adhesive layer 3 are provided in this order on one surface of a base film 1. Although not shown, a releasable substrate sheet (release liner) may be provided on the surface (the surface opposite to the surface facing the substrate film 1) of the active energy ray-curable adhesive layer 3 of the adhesive tape 10 for processing a workpiece. The base film 1 is composed of a polyester resin composition. The intermediate layer 2 is formed of a resin composition containing a predetermined (meth) acrylate copolymer. The active energy ray-curable adhesive layer 3 is formed of an adhesive composition containing a (meth) acrylate copolymer having a photosensitive carbon-carbon double bond introduced into a side chain of a predetermined (meth) acrylate copolymer Base Polymer (BP).
Fig. 2 is a cross-sectional view showing an example of another embodiment of a structure of an adhesive tape for processing a workpiece to which the present embodiment is applied. As shown in fig. 2, the adhesive tape 10 for work processing has a structure in which the intermediate layer 2 and the active energy ray-curable adhesive layer 3 are provided in this order on one surface of the base film 1, but the base film 1 of fig. 1 is a single-layer structure, whereas the base film 1 of fig. 2 has a laminated structure of a resin layer 1a composed of a polyester resin composition and a resin layer 1b composed of a resin composition containing, for example, a resin other than polyester. The other constitution is the same as that of FIG. 1.
The adhesive tape 10 for processing a workpiece having such a configuration can be applied, for exampleThe cutting process is used for cutting and separating hard workpieces such as a glass substrate, a crystal substrate, a sapphire glass substrate, etc., which are brittle and liable to crack, such as various circuit formation and surface treatment, into pieces. The present invention can also be used in a dicing process of a compound semiconductor wafer such as a normal silicon semiconductor wafer, silicon carbide, gallium arsenic, gallium phosphorus, and gallium nitride. Specifically, as the dicing tape, as shown in fig. 3 and 4, specifically, it is used. First, after the active energy ray-curable adhesive layer 3 of the outer edge portion of the work processing adhesive tape 10 punched into a circular shape is bonded to the SUS ring frame 20, for example, the glass substrate 30 is bonded to the active energy ray-curable adhesive layer 3 of the center portion of the work processing adhesive tape 10 so that the surface side where no circuit formation is performed is in contact with the active energy ray-curable adhesive layer 3. Here, the thickness of the work such as a glass substrate, a crystal substrate, or a sapphire glass substrate is, for example, 50 μm to 5000 μm. Next, the glass substrate 30 is cut into glass chips 30a of a predetermined size by the cutting blade 40 rotating at a high speed while spraying the washing cooling water. Here, the area of the plane of the chip is, for example, 1X 10 -6 mm 2 ～9mm 2 Is not limited in terms of the range of (a). After cutting, the active energy ray-curable adhesive layer 3 to which the work is attached is irradiated with active energy rays such as ultraviolet rays (UV) from the side of the base film 1 of the work processing adhesive tape 10, the adhesive force of the active energy ray-curable adhesive layer 3 is reduced, and the glass chip 30a is picked up (peeled off) from the active energy ray-curable adhesive layer 3 of the work processing adhesive tape 10. Thus, a high-quality glass chip 30a with suppressed defects can be obtained.
Fig. 5 is a perspective view showing a state in which the unnecessary adhesive tape 10 for processing a work is peeled from the ring frame 20 after the completion of the pickup of all the glass chips 30a from below. The adhesive tape for work processing is manually peeled from the ring frame, but may be peeled by using a peeling device or the like. The ring frame 20 from which the adhesive tape 10 for workpiece processing is peeled off is washed and reused as needed, but if the adhesive layer of the active energy ray-curable adhesive layer is peeled off from the base film 1 and transferred (paste remains) to the surface of the ring frame 10 at the time of peeling off the adhesive tape 10 for workpiece processing, washing takes time, and the operation efficiency is lowered.
The adhesive tape 10 for work processing having such a configuration can be used in a back grinding (back grinding) step for grinding semiconductor wafers such as silicon wafers subjected to various circuit formation and other surface processing to an extremely thin thickness. Specifically, as the back surface polishing tape, as shown in fig. 6, specifically, the one is used. First, as shown in fig. 6 (a), the active energy ray-curable adhesive layer 3 side of the adhesive tape 10 for workpiece processing is bonded to the surface side of the semiconductor wafer 50 having a thickness of 775 μm, for example, on which the circuit 51 is formed. Next, the semiconductor wafer 50 is polished to a predetermined thickness from the surface opposite to the surface on which the circuit formation is performed by a polishing machine (polishing wheel) 60 while polishing water is supplied. At this time, the semiconductor wafer 50 is sucked and held on a holding table (not shown) by the work processing adhesive tape 10. Fig. 6 (b) shows a state in which the semiconductor wafer 50 'in which polishing of the semiconductor wafer 50 is completed and the semiconductor wafer 50' is thinned to a predetermined thickness is held in the adhesive tape 10 for workpiece processing. Here, the thickness of the semiconductor wafer 50' in a thinned state is, for example, in a range of 20 μm to 100 μm.
After polishing, first, the active energy ray-curable adhesive layer 3 to which the thinned semiconductor wafer 50' is attached is irradiated with active energy rays such as ultraviolet rays (UV) from the substrate film 1 side of the adhesive tape 10 for work processing, and the active energy ray-curable adhesive layer 3 is cured to reduce the adhesive force. Next, as shown in fig. 7 (a), after the SUS ring frame 20 is bonded to the active energy ray-curable adhesive layer 3 of the outer edge portion of the separately prepared dicing tape 11, the active energy ray-curable adhesive layer 3 of the center portion of the dicing tape 11 is bonded so that the polished surface side of the thinned semiconductor wafer 50' is brought into contact with the active energy ray-curable adhesive layer 3. Next, an elongated (for example, 50mm wide×60mm long) release tape 12 is bonded to the back surface of the base film 1 of the adhesive tape 10 for workpiece processing by pressure bonding or thermocompression bonding. The work-processing adhesive tape 10 has substantially the same shape as the semiconductor wafer 50' to be thin, and does not serve as a start point of peeling, and therefore the long peeling tape 12 is firmly fixed to serve as a start point of peeling. Then, before the dicing step of the subsequent step, the work processing adhesive tape 10 is peeled from the surface of the thinned semiconductor wafer 50' having the circuit 51 on the surface, using the peeling tape 12 as a starting point, as shown in fig. 7 (b). The peeling is performed manually or by using a peeling device or the like. At this time, the thinned semiconductor wafer 50' is sucked and held on a holding table (not shown) by the dicing tape 11. Thus, the thinned semiconductor wafer 50' having a high thickness accuracy can be obtained without contamination such as paste residue on the surface.
< adhesive tape for workpiece processing >)
(substrate film)
The substrate film 1 in the adhesive tape 10 for processing a workpiece according to the present embodiment will be described below. As the base film 1, a film made of a polyester resin composition is used from the viewpoints of tensile strength and rigidity. The film formed of the polyester resin composition is a film containing a polyester as a main component, and the polyester is preferably contained in a proportion of 70 mass% or more, more preferably in a proportion of 80 mass% or more, which is close to the polyester monomer in composition, with respect to the entire resin component (component excluding the resin from the resin composition) in the resin composition constituting the base film 1. The upper limit is not particularly limited, but is 100 mass% or less.
Examples of the polyester as the main component of the base film 1 include crystalline linear saturated polyesters obtained by polycondensation of an aromatic dibasic acid or an ester derivative thereof and a diol or an ester derivative thereof. Specific examples of the polyester include a homo-polyester such as polyethylene terephthalate, polyethylene isophthalate, polybutylene terephthalate, and polyethylene 2, 6-naphthalate, and a copolyester containing a constituent component of these resins as a main component. The polyester may be used by blending the homopolyester with each other or by blending the homopolyester with the copolyester. Among these polyesters, polyethylene terephthalate is particularly preferred, which is easy to obtain, and which is excellent in mechanical strength (tensile strength, rigidity, etc.), transparency, heat resistance, and thickness accuracy, and which is a substrate film 1.
Examples of the aromatic dibasic acid of the homo-polyester include terephthalic acid and 2, 6-naphthalene dicarboxylic acid, and examples of the diol include ethylene glycol, diethylene glycol and 1, 4-cyclohexanedimethanol. The total of the repeating units of the homo-polyester, that is, the main repeating units including the aromatic dibasic acid constituent and the diol constituent is preferably 80 mol% or more, more preferably 90 mol% or more, and still more preferably 95 mol% or more of the total repeating units.
Examples of the aromatic dibasic acid of the copolyester include hydroxycarboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid, 2, 6-naphthalenedicarboxylic acid, adipic acid, sebacic acid, and parahydroxybenzoic acid, and these can be used alone or in combination of 2 or more.
Examples of the diols used in the copolyester include ethylene glycol, diethylene glycol, 1, 4-butanediol, propylene glycol, and neopentyl glycol, and these can be used alone or in combination of 2 or more.
The mass ratio of the copolymerized component of the above-mentioned copolymerized polyester is preferably less than 20 mass%. When the mass ratio is less than 20 mass%, the mechanical strength, transparency, heat resistance, and thickness accuracy of the base film 1 can be maintained.
The polyester is preferably contained in a proportion of 70 mass% or more with respect to the entire resin component (component excluding the additive other than the resin from the resin composition) constituting the base film 1, but the resin component may contain, for example, an aromatic ether compound, an ethylene-vinyl acetate copolymer, an ethylene- (meth) acrylic acid copolymer, a polyolefin-based elastomer, a polyamide-based elastomer, a polycarbonate-based resin, an ionomer resin, or the like as another resin other than the polyester, as required. From the viewpoint of maintaining the mechanical strength, transparency, heat resistance, and thickness accuracy of the base film 1, the other resin is preferably contained in a proportion of 30 mass% or less, more preferably 20 mass% or less, relative to the entire resin component (component excluding the additive other than the resin from the resin composition) constituting the base film 1.
In addition, as another embodiment of the polyester as the main component of the base film 1, a so-called polyester-polyether block type thermoplastic elastomer in which an aromatic polyester is used for the hard segment and a polyether is used for the soft segment can be exemplified; the hard segment is an aromatic polyester, and the soft segment is a so-called polyester-polyester block thermoplastic elastomer of an aliphatic polyester. Specifically, the polyester-polyether block thermoplastic elastomer may be a polybutylene terephthalate as the polyester of the hard segment, a polytetramethylene ether glycol as the polyether of the soft segment, a polybutylene terephthalate as the polyester of the hard segment, a polylactone as the polyester-polyester block thermoplastic elastomer, or the like.
The polyester resin composition constituting the base film 1 is preferably blended with particles for the main purpose of imparting slipperiness to the base film 1. The type of the particles to be blended is not particularly limited as long as it is a particle capable of imparting slipperiness, and specific examples thereof include inorganic particles such as silica, calcium carbonate, magnesium carbonate, barium carbonate, calcium sulfate, calcium phosphate, magnesium phosphate, kaolin, alumina, and titanium oxide; heat-resistant organic particles such as thermosetting urea resin, thermosetting phenol resin, thermosetting epoxy resin, benzoguanamine resin, and the like. The shape of the particles to be used is not particularly limited, and any of spherical, block-shaped, rod-shaped, flat and the like may be used. The series of particles may be used in combination of 2 or more kinds as needed.
The length average particle diameter of the particles is usually 0.01 μm or more and 3 μm or less, and preferably 0.01 μm or more and 1 μm or less. When the average particle diameter is within the above range, appropriate slipperiness and smoothness can be imparted to the base film 1. The content of the particles is usually in the range of 0.001 mass% to 5 mass%, preferably 0.005 mass% to 3 mass%, based on the entire resin component constituting the base film 1. When the content of the particles is within the above range, appropriate slipperiness and smoothness can be imparted.
The polyester resin composition may contain, in addition to the particles, a conventionally known catalyst, an antioxidant, an antistatic agent, a heat stabilizer, a lubricant, a dye, a pigment, and the like as required, within a range that does not impair the effects of the present invention.
As the base film 1 formed from the polyester resin composition, any of an unstretched polyester film, a uniaxially stretched polyester film, and a biaxially stretched polyester film can be used, and a biaxially stretched polyester film is preferable. Specifically, a biaxially stretched polyethylene terephthalate film is preferable.
The base film 1 may be a single layer or may be a laminate of 2 or more layers. From the viewpoints of simplification of the process and thickness accuracy, the base film 1 is preferably a single-layer structure as shown in fig. 1. When the base film 1 is formed of 2 layers, for example, as shown in fig. 2, the base film has a laminated structure of a resin layer 1a made of a polyester resin composition and a resin layer 1b made of a resin composition other than polyester. Here, the resin layer 1a is a layer directly contacting the intermediate layer 2, and when the base film 1 is formed by laminating, at least the resin layer 1a directly contacting the intermediate layer 2 is formed of the polyester resin composition. The resin layer 1b may be a layer made of a resin composition other than polyester, or may be a layer made of a polyester resin composition. The resin component of the resin composition other than polyester may be the same as the resin exemplified as the other resin other than polyester.
The total thickness of the base film 1 is not particularly limited as long as it is in a range in which a film can be formed, and is usually in a range of 12 μm to 250 μm, preferably 25 μm to 188 μm, and more preferably 38 μm to 125 μm. If the total thickness of the base film 1 is less than 12 μm, the workability may be deteriorated during the production of the adhesive tape 10 for workpiece processing and during the use in the process, and as a result, the quality of the workpiece to be processed (glass chip 30a, thinned semiconductor wafer 50', etc.) may be poor. On the other hand, if the total thickness exceeds 250 μm, the rigidity becomes too high, and as a result, there is a concern that the quality of the workpiece to be processed is poor.
In the case where the base film 1 is formed by stacking 2 or more layers, the total thickness of the layers made of the polyester resin composition depends on the total thickness of the base film 1, and thus cannot be defined in any way, and for example, it is preferable to set the thickness to a ratio of 50% or more with respect to the total thickness of the base film 1. When the ratio is 50%, the quality of the workpiece to be processed is good.
(intermediate layer)
The intermediate layer 2 in the adhesive tape 10 for processing a workpiece according to the present embodiment will be described below. The intermediate layer 2 is formed from a resin composition containing a ternary or higher (meth) acrylate copolymer (A1) (hereinafter, sometimes simply referred to as "(meth) acrylate copolymer (A1)") containing Methyl Acrylate (MA) and methacrylic acid (MAA) as copolymer monomer components, and the Methyl Acrylate (MA) is contained in a range of at least 47 parts by mass to 67 parts by mass and the methacrylic acid (MAA) is contained in a range of 2 parts by mass to 7 parts by mass, based on 100 parts by mass of the total amount of the copolymer monomer components constituting the ternary or higher (meth) acrylate copolymer (A1). The content of the ternary or higher (meth) acrylic copolymer (a) is preferably 90 mass% or more, more preferably 95 mass% or more, based on the total amount of the resin composition.
[ (meth) acrylate copolymer (A1) ]
In the above-mentioned ternary or higher (meth) acrylate copolymer (A1), by containing Methyl Acrylate (MA) and methacrylic acid (MAA) as the copolymer monomer components in the amounts within the above-mentioned ranges, both the adhesion between the base film 1 and the intermediate layer 2 and the adhesion between the intermediate layer 2 and an active energy ray-curable adhesive layer 3 described later become good, and even after the active energy rays are irradiated to the adhesive tape 10 for workpiece processing, the adhesion can be sufficiently maintained at a level that does not cause a problem in workpiece processing. As a result, the quality of the workpiece to be processed can be improved.
In the ternary or higher (meth) acrylate copolymer (A1), the copolymer monomer components other than the Methyl Acrylate (MA) and the methacrylic acid (MAA) are contained in a range of 26 parts by mass to 51 parts by mass, based on 100 parts by mass of the total amount of the copolymer monomer components constituting the (meth) acrylate copolymer (A1).
The copolymer monomer component other than the Methyl Acrylate (MA) and the methacrylic acid (MAA) is not particularly limited as long as it is a monomer copolymerizable with the Methyl Acrylate (MA) and the methacrylic acid (MAA), and examples thereof include (meth) acrylate monomers having a linear or branched alkyl group having 2 to 20 carbon atoms, cycloalkyl (meth) acrylate monomers, functional group-containing monomers, vinyl acetate, styrene, acrylonitrile, N-methyl vinyl pyrrolidone, and the like. These monomers can be used alone, or 2 or more kinds can be used in combination.
Examples of the (meth) acrylate monomer having a linear or branched alkyl group having 2 or more and 20 or less include ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, sec-butyl (meth) acrylate, t-butyl (meth) acrylate, pentyl (meth) acrylate, isopentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, undecyl (meth) acrylate, dodecyl (meth) acrylate, tridecyl (meth) acrylate, tetradecyl (meth) acrylate, hexadecyl (meth) acrylate, octadecyl (meth) acrylate, and eicosyl (meth) acrylate. Among these, (meth) acrylate monomers having a linear or branched alkyl group having 2 to 8 carbon atoms are preferable from the viewpoints of versatility, adhesion of the intermediate layer 2 to the active energy ray-curable adhesive layer 3, and adhesion of the intermediate layer 2 to the substrate film 1, and specifically, ethyl (meth) acrylate, n-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and the like are preferable.
Specific examples of the cycloalkyl (meth) acrylate monomer include cyclopentyl (meth) acrylate, cyclohexyl (meth) acrylate, and dicyclopentanyl (meth) acrylate.
Specific examples of the functional group-containing monomer include carboxyl group-containing monomers such as acrylic acid, carboxyethyl (meth) acrylate, carboxypentyl (meth) acrylate, itaconic acid, maleic acid, fumaric acid, and crotonic acid; anhydride monomers such as maleic anhydride and itaconic anhydride; hydroxy group-containing monomers such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 8-hydroxyoctyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate, 12-hydroxylauryl (meth) acrylate, and (4-hydroxymethylcyclohexyl) methyl (meth) acrylate; sulfonic acid group-containing monomers such as styrene sulfonic acid, allyl sulfonic acid, 2- (meth) acrylamide-2-methylpropane sulfonic acid, (meth) acrylamide propane sulfonic acid, sulfopropyl (meth) acrylate, and (meth) acryloxynaphthalene sulfonic acid; 2-hydroxyethyl acryl phosphate and other phosphate group-containing monomers; glycidyl group-containing monomers such as glycidyl (meth) acrylate; amide group-containing monomers such as (meth) acrylic acid amide and (meth) acrylic acid N-methylol amide; amino group-containing monomers such as alkylaminoalkyl (meth) acrylates, e.g., dimethylaminoethyl (meth) acrylate and t-butylaminoethyl (meth) acrylate. Among these, acrylic acid, 2-hydroxyethyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, amide (meth) acrylate, and the like are preferably used from the viewpoints of versatility, adhesion of the intermediate layer 2 to the active energy ray-curable adhesive layer 3, adhesion of the intermediate layer 2 to the substrate film 1, and improvement of the cohesive force of the intermediate layer 2.
As the above-mentioned ternary or higher (meth) acrylate copolymer (A1) in the present invention, a ternary or higher (meth) acrylate copolymer containing 2-ethylhexyl acrylate (2-EHA) as a copolymer monomer component in addition to the above-mentioned predetermined copolymer monomer components of Methyl Acrylate (MA) and methacrylic acid (MAA) is preferably used. Specific examples of such a ternary or higher (meth) acrylate copolymer include:
(1) Terpolymers of 2-ethylhexyl acrylate (2-EHA), methyl Acrylate (MA) and methacrylic acid (MAA);
(2) A tetrapolymer of 2-ethylhexyl acrylate (2-EHA), n-butyl acrylate (n-BA), methyl Acrylate (MA) and methacrylic acid (MAA);
(3) A tetrapolymer of 2-ethylhexyl acrylate (2-EHA), methyl Acrylate (MA), 2-hydroxyethyl acrylate (2-HEA) and methacrylic acid (MAA);
(4) A tetrapolymer of 2-ethylhexyl acrylate (2-EHA), methyl Acrylate (MA), ethyl Acrylate (EA) and methacrylic acid (MAA);
(5) 2-ethylhexyl acrylate (2-EHA), methyl Acrylate (MA), acrylic Acid (AA), and methacrylic acid (MAA), and the like.
Among these, from the viewpoint of versatility, a ternary (meth) acrylate copolymer having 2-ethylhexyl acrylate (2-EHA), methyl Acrylate (MA) and methacrylic acid (MAA) as copolymer monomer components, or a ternary copolymer of n-butyl acrylate (n-BA), methyl Acrylate (MA) and methacrylic acid (MAA) can be suitably used, and a ternary (meth) acrylate copolymer having 2-ethylhexyl acrylate (2-EHA), methyl Acrylate (MA) and methacrylic acid (MAA) as copolymer monomer components can be more suitably used.
In the case of using the ternary (meth) acrylate copolymer of 2-ethylhexyl acrylate (2-EHA), methyl Acrylate (MA) and methacrylic acid (MAA), the respective monomer components are preferably contained in a range of 26 to 51 parts by mass, in a range of 47 to 67 parts by mass, and in a range of 2 to 7 parts by mass, in such a manner that the total amount of the monomer components of the copolymer is 100 parts by mass, based on 100 parts by mass of the total amount of the monomer components constituting the ternary (meth) acrylate copolymer.
The above (meth) acrylate copolymer (A1) having three or more elements is obtained as follows: the Methyl Acrylate (MA) monomer, the methacrylic acid (MAA) monomer, and 1 or 2 or more monomers selected from the above monomers other than the two monomers are blended as a copolymer monomer component in a predetermined amount, and the blended mixture is polymerized. The polymerization may be carried out in any of solution polymerization, emulsion polymerization, bulk polymerization, suspension polymerization, and the like. The weight average molecular weight (Mw) of the ternary or higher (meth) acrylate copolymer (A1) is preferably 10 ten thousand or more from the viewpoint of improving the cohesive force of the intermediate layer 2, and is preferably 150 ten thousand or less from the viewpoint of suitably coating a solution of the intermediate layer 2 with a resin composition. That is, the weight average molecular weight (Mw) is preferably in the range of 10 to 150 tens of thousands, more preferably in the range of 30 to 100 tens of thousands. Here, the weight average molecular weight (Mw) is a weight average molecular weight in terms of standard polystyrene measured using Gel Permeation Chromatography (GPC).
The glass transition temperature (Tg) of the ternary or higher (meth) acrylate copolymer (A1) is not particularly limited as long as it does not interfere with the effect of the present invention, and is preferably in the range of-36 ℃ to-9 ℃, more preferably in the range of-36 ℃ to-18 ℃ from the viewpoints of adhesion between the base film 1 and the intermediate layer 2, adhesion between the intermediate layer 2 and an active energy ray-curable adhesive layer 3 described later, and processing quality of a workpiece. The glass transition temperature (Tg) is a theoretical value calculated from Fox formula shown in the following general formula (1) based on the composition of the monomer components constituting the above-mentioned ternary or higher (meth) acrylate copolymer (A1).
[ number 1]
1/Tg＝W 1 /Tg 1 +W 2 /Tg 2 +···+W n /Tg n (1)
[ in the above general formula (1), tg is the glass transition temperature (unit: K) of the (meth) acrylate copolymer (A1) having a Tg of three or more i (i=1, 2, the glass transition temperature of monomer i when it forms a homopolymer (unit: K), W i (i=1, 2, N) represents the entirety of monomers i mass fraction in the monomer component.]
The glass transition temperature (Tg) of the homopolymer can be found, for example, in "Polymer Handbook" (j brandrup and e.h.immergut, vol. Interscience Publishers) and the like.
If the glass transition temperature (Tg) is within the above range, for example, when a brittle and easily cracked work such as the glass substrate 30 is cut by the rotary cutting blade 40, the work on the adhesive layer 3 is held and fixed well, and further the shake can be suppressed, so that defects, dimensional displacement of chips, and positional displacement can be suppressed. In addition, it is possible to suppress the paste residue on the ring frame 20 and the transfer of the adhesive layer when the adhesive tape 10 for workpiece processing is peeled off from the ring frame 20 after dicing. In addition, for example, when polishing the semiconductor wafer 50, the height difference of the circuit 51, the electrode, and the like on the surface of the semiconductor wafer 50 can be appropriately followed, so that the paste residue at the peripheral edge portion of the circuit surface when the adhesive tape 10 for workpiece processing is peeled from the thinned semiconductor wafer 50' can be suppressed; uniformity of thickness of the thinned semiconductor wafer 50' can be ensured. In addition, the transfer of the adhesive layer 3 to the thinned semiconductor wafer 50' can also be suppressed.
Further, the acid value of the (meth) acrylate copolymer (A1) is not particularly limited as long as it does not hinder the effect of the present invention, and is preferably 13.0mgKOH/g or more from the viewpoint of the adhesion between the base film 1 and the intermediate layer 2, the adhesion between the intermediate layer 2 and the active energy ray-curable adhesive layer 3 described later, and the improvement in the cohesive force of the intermediate layer 2, and is preferably 50.7mgKOH/g or less from the viewpoint of the gelation inhibition during polymerization of the copolymer (A1) and the rigidity of the intermediate layer 2 (the decrease in the adhesive force before irradiation of the active energy rays and the decrease in the following property due to the increase in the rigidity) of the adhesive tape 10 for workpiece processing. That is, the acid value is preferably in the range of 13.0mgKOH/g to 50.7 mgKOH/g.
The hydroxyl value of the ternary or higher (meth) acrylate copolymer (A1) is not particularly limited as long as it does not interfere with the effect of the present invention, and is preferably in the range of 0mgKOH/g to 96.6mgKOH/g from the viewpoints of adhesion between the base film 1 and the intermediate layer 2, adhesion between the intermediate layer 2 and an active energy ray-curable adhesive layer 3 described later, and rigidity of the intermediate layer 2 (decrease in adhesive force before irradiation of active energy rays of the adhesive tape 10 for workpiece processing due to increase in rigidity, decrease in level-difference follow-up property).
[ Cross-linking agent ]
In order to enhance the cohesive force of the intermediate layer 2, the resin composition constituting the intermediate layer 2 preferably contains a crosslinking agent capable of reacting with the functional group of the ternary or higher (meth) acrylate copolymer (A1). The crosslinking agent is not particularly limited, and a known crosslinking agent having a functional group capable of reacting with a carboxyl group, a hydroxyl group or a glycidyl group which is optionally introduced, which is the functional group of the above-mentioned ternary or higher (meth) acrylate copolymer (A1) can be used. Specifically, examples thereof include polyisocyanate-based crosslinkers, epoxy-based crosslinkers, metal chelate-based crosslinkers, aziridine-based crosslinkers, melamine-resin-based crosslinkers, urea-resin-based crosslinkers, acid anhydride compound-based crosslinkers, polyamine-based crosslinkers, and carboxyl-containing polymer-based crosslinkers. Among these, a polyisocyanate-based crosslinking agent or an epoxy-based crosslinking agent is preferably used from the viewpoints of reactivity and versatility. These crosslinking agents may be used alone, or 2 or more kinds may be used in combination. The amount of the crosslinking agent to be blended is preferably in the range of 0.01 to 10.0 parts by mass, more preferably in the range of 0.1 to 5.0 parts by mass, based on 100 parts by mass of the solid content of the ternary or higher (meth) acrylate copolymer (A1).
Examples of the polyisocyanate-based crosslinking agent include a polyisocyanate compound having an isocyanurate ring, an adduct polyisocyanate compound obtained by reacting trimethylolpropane with hexamethylene diisocyanate, an adduct polyisocyanate compound obtained by reacting trimethylolpropane with toluene diisocyanate, an adduct polyisocyanate compound obtained by reacting trimethylolpropane with xylylene diisocyanate, and an adduct polyisocyanate compound obtained by reacting trimethylolpropane with isophorone diisocyanate. They can be used in combination of 1 or more than 2.
Examples of the epoxy-based crosslinking agent include bisphenol a-epichlorohydrin-based epoxy resin, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, glycerol triglycidyl ether, 1, 6-hexanediol diglycidyl ether, trimethylolpropane triglycidyl ether, sorbitol polyglycidyl ether, pentaerythritol polyglycidyl erythritol, diglycidyl polyglycidyl ether, 1,3 '-bis (N, N-diglycidyl aminomethyl) cyclohexane, N' -tetraglycidyl m-xylylenediamine, and the like. They can be used in combination of 1 or more than 2.
[ thickness ]
The thickness of the intermediate layer 2 is not particularly limited as long as it is appropriately adjusted in accordance with the work, and is preferably 5 μm or more from the viewpoint of adhesion between the base film 1 and the intermediate layer 2 and adhesion between the intermediate layer 2 and an active energy ray-curable adhesive layer 3 described later, and is preferably 150 μm or less from the viewpoint of appropriate application and drying of a solution of the resin composition from the intermediate layer 2. That is, the thickness of the intermediate layer 2 is preferably in the range of 5 μm to 150 μm, more preferably in the range of 5 μm to 100 μm.
(active energy ray-curable adhesive layer)
The active energy ray-curable adhesive layer 3 (hereinafter, may be simply referred to as "adhesive layer 3") in the adhesive tape 10 for processing a workpiece according to the present embodiment will be described below. The active energy ray-curable adhesive layer 3 is formed from an adhesive composition containing a (meth) acrylate copolymer (A2) (hereinafter, sometimes simply referred to as "(meth) acrylate copolymer (A2)") having a photosensitive carbon-carbon double bond introduced into a side chain of a binary or higher (meth) acrylate copolymer Base Polymer (BP) and a crosslinking agent. The content ratio of the (meth) acrylate copolymer (A2) to the total amount of the adhesive composition is preferably 90 mass% or more, and more preferably 95 mass% or more.
The method for producing the (meth) acrylate copolymer (A2) having a photosensitive carbon-carbon double bond introduced into the side chain is not particularly limited, and generally includes the following methods: a (meth) acrylate copolymer base polymer is obtained by copolymerizing a copolymer monomer component comprising a (meth) acrylate monomer and a functional group-containing monomer, and a compound (active energy ray-reactive compound) having a functional group capable of undergoing an addition reaction with the functional group of the base polymer and a carbon-carbon double bond is subjected to an addition reaction.
[ (meth) acrylate copolymer Base Polymer (BP) ]
In the binary or higher (meth) acrylate copolymer Base Polymer (BP) (hereinafter, sometimes simply referred to as Base Polymer (BP)) in the present embodiment, n-butyl acrylate (n-BA) is contained as a copolymer monomer component in a proportion of more than 50 parts by mass and 90 parts by mass or less, with the total amount of the copolymer monomer components constituting the (meth) acrylate copolymer Base Polymer (BP) taken as 100 parts by mass.
As described above, in the binary or higher (meth) acrylate copolymer Base Polymer (BP), when the total amount of the copolymer monomer components constituting the Base Polymer (BP) is 100 parts by mass, n-butyl acrylate (n-BA) is contained as the copolymer monomer component in a proportion of more than 50 parts by mass and 90 parts by mass or less, so that the adhesion between the intermediate layer 2 and the adhesive layer 3 can be improved, and the adhesion can be sufficiently maintained at a level that does not cause any trouble in the work processing in both the front and rear of the irradiation of the active energy rays of the adhesive tape 10 for work processing. On the other hand, it is possible to impart high adhesion before irradiation of active energy rays to the adhesive tape 10 for workpiece processing required for holding a workpiece at the time of processing the workpiece, and to suppress the cohesive force of the adhesive layer 3 required for the paste residue to the workpiece at the time of peeling the adhesive tape 10 for workpiece processing from the workpiece to be processed. As a result, the quality of the workpiece to be processed can be improved.
In the binary or higher (meth) acrylate copolymer Base Polymer (BP), when the total amount of the copolymer monomer components constituting the Base Polymer (BP) is 100 parts by mass, it is preferable that the functional group-containing monomer be contained in a proportion of 10 to 34 parts by mass, and that the other copolymer monomer (excluding n-BA and the functional group-containing monomer) be contained in a proportion of 0 to less than 40 parts by mass so that the total amount of the copolymer monomer components becomes 100 parts by mass, as the copolymer monomer components other than n-butyl acrylate (n-BA).
Examples of the functional group-containing monomer include a carboxyl group-containing monomer, an acid anhydride monomer, a hydroxyl group-containing monomer, a sulfonic acid group-containing monomer, a glycidyl group-containing monomer, an amide group-containing monomer, and an amino group-containing monomer, which are the same as those exemplified as the functional group-containing monomer component of the ternary or higher (meth) acrylate copolymer (A1) as the intermediate layer 2. They can be used in combination of 1 or more than 2. Among these, from the viewpoint of easiness of the addition reaction with an active energy ray-reactive compound described later, a hydroxyl group-containing monomer is preferably used. Specific examples of the hydroxyl group-containing monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 8-hydroxyoctyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate, 12-hydroxylauryl (meth) acrylate, and (4-hydroxymethylcyclohexyl) methyl (meth) acrylate. Among these, 2-hydroxyethyl (meth) acrylate and 4-hydroxybutyl (meth) acrylate are preferable from the viewpoint of versatility.
The purpose of copolymerizing the functional group-containing monomer is to: first, with respect to the above-mentioned binary or higher (meth) acrylate copolymer Base Polymer (BP), this functional group is used as an addition reaction site for introducing an active energy ray-reactive carbon-carbon double bond described later by an addition reaction; secondly, as a crosslinking reaction site for reacting with a crosslinking agent to be described later to increase the molecular weight of the (meth) acrylate copolymer (A2); thirdly, active energy ray-curable adhesive layer 3 after the crosslinking reaction is used as an active site (polar point) for improving the initial adhesion between the workpiece and the active energy ray-curable adhesive layer; fourth, as an active site (polar point) for improving adhesion between the intermediate layer 2 and the active energy ray-curable adhesive layer 3, as a result, the content ratio of the functional group-containing monomer is preferably adjusted to be in the range of 10 mass% to 34 mass% with respect to the total amount of the copolymer monomer components constituting the binary or higher (meth) acrylate copolymer Base Polymer (BP) as described above.
In the above-mentioned binary or higher (meth) acrylic copolymer Base Polymer (BP), other copolymer monomers (excluding n-BA and functional group-containing monomers) may be contained as the copolymer monomer component in a proportion of less than 40 mass% relative to the total amount of the copolymer monomer components constituting the above-mentioned (meth) acrylic ester copolymer Base Polymer (BP) as required from the viewpoints of an improvement in the cohesive force, adjustment of the glass transition temperature (Tg), improvement in heat resistance, and the like. The other copolymer monomer component is not particularly limited as long as it is a monomer copolymerizable with the N-butyl acrylate (N-BA) and the functional group-containing monomer, and examples thereof include (meth) acrylate monomers having a linear or branched alkyl group having 1 to 20 carbon atoms, cycloalkyl (meth) acrylate monomers, vinyl acetate, styrene, acrylonitrile, and N-methyl vinyl pyrrolidone. These monomers can be used alone, or 2 or more kinds can be used in combination.
The (meth) acrylate monomer having a linear or branched alkyl group having 1 to 20 carbon atoms is specifically the same monomer component as the monomer component exemplified as the copolymer monomer component of the ternary or higher (meth) acrylate copolymer (A1) of the intermediate layer 2, that is, the (meth) acrylate monomer having a linear or branched alkyl group having 2 to 20 carbon atoms, except for methyl (meth) acrylate having a linear alkyl group having 1 carbon atoms. Among these, methyl (meth) acrylate, ethyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, dodecyl (meth) acrylate, tridecyl (meth) acrylate, stearyl (meth) acrylate, and the like are preferable from the viewpoint of versatility.
Specific examples of the cycloalkyl (meth) acrylate monomer include cyclopentyl (meth) acrylate, cyclohexyl (meth) acrylate, and dicyclopentanyl (meth) acrylate.
As the binary or higher (meth) acrylate copolymer Base Polymer (BP) in the present embodiment, a binary or higher (meth) acrylate copolymer containing n-butyl acrylate (n-BA) and 2-hydroxyethyl acrylate (2-HEA) as copolymer monomer components is preferably used. Specific examples of such binary or higher (meth) acrylate copolymers include:
(1) A binary copolymer of n-butyl acrylate (n-BA) and 2-hydroxyethyl acrylate (2-HEA);
(2) Terpolymers of n-butyl acrylate (n-BA), 2-hydroxyethyl acrylate (2-HEA) and methacrylic acid (MAA);
(3) A tetrapolymer of n-butyl acrylate (n-BA), 2-ethylhexyl acrylate (2-EHA), 2-hydroxyethyl acrylate (2-HEA) and methacrylic acid (MAA);
(4) N-butyl acrylate (n-BA), 2-hydroxyethyl acrylate (2-HEA), methyl Methacrylate (MMA), and methacrylic acid (MAA), and the like.
Among these, from the viewpoint of versatility, a binary (meth) acrylate copolymer having n-butyl acrylate (n-BA) and 2-hydroxyethyl acrylate (2-HEA) as copolymer monomer components, or a ternary (meth) acrylate copolymer having n-butyl acrylate (n-BA), 2-hydroxyethyl acrylate (2-HEA) and methacrylic acid (MAA) as copolymer monomer components can be suitably used, and a ternary (meth) acrylate copolymer having n-butyl acrylate (n-BA), 2-hydroxyethyl acrylate (2-HEA) and methacrylic acid (MAA) as copolymer monomer components can be more suitably used.
In the case of using the binary (meth) acrylate copolymer of n-butyl acrylate (n-BA) and 2-hydroxyethyl acrylate (2-HEA) as the (meth) acrylate copolymer Base Polymer (BP) of the above binary or higher, it is preferable that the total amount of the copolymer monomer components constituting the ternary (meth) acrylate copolymer is adjusted to 100 parts by mass based on the total amount of the copolymer monomer components, the n-butyl acrylate (n-BA) is contained in a range of 66 parts by mass to 90 parts by mass, and the 2-hydroxyethyl acrylate (2-HEA) is contained in a range of 10 parts by mass to 34 parts by mass.
When the ternary (meth) acrylate copolymer of n-butyl acrylate (n-BA), 2-hydroxyethyl acrylate (2-HEA) and methacrylic acid (MAA) is used as the binary or higher (meth) acrylate copolymer Base Polymer (BP), it is preferable that the total amount of the monomer components constituting the ternary (meth) acrylate copolymer be adjusted so that the total amount of the monomer components is 100 parts by mass, the range of 66 parts by mass or more and 90 parts by mass or less, the range of 9.8 parts by mass or more and 31 parts by mass or less, and the range of 0.2 parts by mass or more and 3 parts by mass or less, and the total amount of the monomer components of the copolymer be adjusted so that the total amount of the monomer components is 100 parts by mass.
The glass transition temperature (Tg) of the binary or higher (meth) acrylate copolymer Base Polymer (BP) is not particularly limited as long as it is in a range that does not hinder the effect of the present invention, and is preferably in a range of-50 ℃ to-39 ℃ from the viewpoints of adhesion between the intermediate layer 2 and the active energy ray-curable adhesive layer 3, adhesion control before and after irradiation with active energy rays of the adhesive tape for workpiece processing, and processing quality of the workpiece. The glass transition temperature (Tg) is a theoretical value calculated by Fox equation based on the composition of the monomer components constituting the above binary or higher (meth) acrylate copolymer Base Polymer (BP).
If the glass transition temperature (Tg) is within the above range, for example, when a brittle and easily cracked work such as the glass substrate 30 is cut by the rotary cutting blade 40, the work on the adhesive layer 3 can be firmly fixed, and therefore, positional displacement of the chip and scattering of the chip can be suppressed. Further, since the adhesion between the intermediate layer 2 and the adhesive layer 3 is improved, it is possible to suppress the paste residue on the ring frame 20 and the transfer of the adhesive layer 3 when the adhesive tape 10 for workpiece processing is peeled from the ring frame 20 after dicing. Further, for example, when polishing the semiconductor wafer 50, the height difference of the circuit 51, the electrode, and the like on the surface of the semiconductor wafer 50 can be appropriately followed, and thus, the paste residue at the peripheral edge portion of the circuit surface and the transfer of the adhesive layer 3 to the thinned semiconductor wafer 50 'at the time of peeling the adhesive tape 10 for workpiece processing from the thinned semiconductor wafer 50' can be suppressed.
[ A (meth) acrylate copolymer (A2) having a photosensitive carbon-carbon double bond introduced into the side chain ]
As described above, the (meth) acrylate copolymer (A2) having a photosensitive carbon-carbon double bond introduced into the side chain can be obtained as follows: the functional group introduced into the side chain of the (meth) acrylate copolymer Base Polymer (BP) by copolymerizing the functional group-containing monomer is obtained by an addition reaction with a compound (active energy ray-reactive compound) having a functional group capable of undergoing an addition reaction with the functional group and a carbon-carbon double bond. Examples of such active energy ray-reactive compounds include compounds having isocyanate groups and carbon-carbon double bonds, compounds having carboxyl groups and carbon-carbon double bonds, compounds having glycidyl groups and carbon-carbon double bonds, compounds having amino groups and carbon-carbon double bonds, and the like. These radiation-reactive compounds may be used singly or in combination.
Specific examples of the addition reaction include the following methods: (1) A method in which a hydroxyl group-containing monomer is used as a functional group-containing monomer component of the binary or higher (meth) acrylate copolymer Base Polymer (BP), and the hydroxyl group is subjected to an addition reaction with an isocyanate group of a compound having an isocyanate group and a carbon-carbon double bond (active energy ray-reactive compound); (2) A method in which a carboxyl group-containing monomer is used as a functional group-containing monomer component of the Base Polymer (BP), and the carboxyl group is subjected to an addition reaction with a glycidyl group of a compound having a glycidyl group and a carbon-carbon double bond (active energy ray-reactive compound); (3) A method in which a glycidyl group-containing monomer is used as a functional group-containing monomer component of the Base Polymer (BP), and the glycidyl group is subjected to an addition reaction with a carboxyl group of a compound having a carboxyl group and a carbon-carbon double bond (active energy ray-reactive compound); (4) And a method in which an amino group-containing monomer is used as a functional group-containing monomer component of the Base Polymer (BP), and the amino group is subjected to an addition reaction with an isocyanate group of a compound having an isocyanate group and a carbon-carbon double bond (active energy ray-reactive compound).
Among the above-mentioned addition reactions, a method of adding a hydroxyl group to an isocyanate group of a compound having an isocyanate group and a carbon-carbon double bond (active energy ray-reactive compound) using a hydroxyl group-containing monomer as a functional group-containing monomer component of the above-mentioned binary or higher (meth) acrylate copolymer Base Polymer (BP) is most suitable from the viewpoints of easiness of the reaction tracking (stability of control) and easiness of the technique. Examples of such a compound having an isocyanate group and a carbon-carbon double bond (active energy ray-reactive compound) include an isocyanate compound having a (meth) acryloyloxy group. Specifically, 2-methacryloxyethyl isocyanate, 4-methacryloxyn-butyl isocyanate, 2-acryloxyethyl isocyanate, m-isopropenyl- α, α -dimethylbenzyl isocyanate and the like are exemplified. Among these, 2-methacryloyloxyethyl isocyanate is preferable from the viewpoint of versatility.
In the addition reaction, a polymerization inhibitor is preferably used to maintain the active energy ray reactivity of the carbon-carbon double bond. As such a polymerization inhibitor, a quinone polymerization inhibitor such as hydroquinone-monomethyl ether is preferable. The amount of the polymerization inhibitor is not particularly limited, and is usually preferably in the range of 0.01 parts by mass to 0.1 parts by mass relative to 100 parts by mass of the binary or higher (meth) acrylate copolymer Base Polymer (BP).
In the addition reaction, (1) in order to crosslink the functional group of the (meth) acrylate copolymer (A2) with the crosslinking agent added later as a reaction site, and further increase the molecular weight, (2) in order to improve the initial adhesion between the active energy ray-curable adhesive layer 3 after the crosslinking reaction and the work, that is, the adhesion of the adhesive tape 10 for work processing to the work before irradiation with active energy rays, the functional group is preferably left in the adhesive composition after the crosslinking reaction. On the other hand, in order to sufficiently decrease the adhesive force by curing and shrinking the adhesive layer 3 when the active energy rays are irradiated to the adhesive tape 10 for workpiece processing after workpiece processing, the peeling from the workpiece is easy, and it is also necessary to introduce a photosensitive carbon-carbon double bond in such a manner that the concentration of the (meth) acrylate copolymer Base Polymer (BP) becomes an appropriate range. In view of both these problems, for example, in the case of subjecting an isocyanate compound having a (meth) acryloyloxy group to an addition reaction with a (meth) acrylate copolymer Base Polymer (BP) having a hydroxyl group in a side chain, it is preferable to use an amount in a ratio of 22 mol% to 99 mol% as one standard of the (meth) acryloyloxy group-containing isocyanate compound to the total number of moles of hydroxyl group-containing monomer components as the copolymer monomer components of the Base Polymer (BP). More preferably, the amount is in the range of 40 to 90 mol%, still more preferably 50 to 85 mol%.
The (meth) acrylate copolymer (A2) having a photosensitive carbon-carbon double bond introduced into the side chain of the binary or higher (meth) acrylate copolymer Base Polymer (BP) according to the present embodiment is obtained as follows: the n-butyl acrylate (n-BA) monomer, the functional group-containing monomer, and, if necessary, 1 or 2 or more monomers selected from the above monomers other than the two monomers are blended as a copolymer monomer component in a predetermined amount, the blended mixture is polymerized to synthesize a Base Polymer (BP), and then an active energy ray-reactive compound is subjected to an addition reaction in the presence of an organometallic catalyst. The polymerization may be carried out by any of solution polymerization, emulsion polymerization, bulk polymerization, suspension polymerization, and the like. The weight average molecular weight (Mw) of the (meth) acrylate copolymer base polymer (A2) is preferably 10 ten thousand or more from the viewpoint of improving the cohesive force of the active energy ray-curable adhesive layer 3, and is preferably 150 ten thousand or less from the viewpoint of suitably coating a solution of the adhesive composition of the active energy ray-curable adhesive layer 3. That is, the weight average molecular weight (Mw) is preferably in the range of 10 to 150 tens of thousands, more preferably in the range of 30 to 100 tens of thousands. Here, the weight average molecular weight (Mw) is a weight average molecular weight in terms of standard polystyrene measured using Gel Permeation Chromatography (GPC).
The acid value of the (meth) acrylate copolymer (A2) is not particularly limited as long as it does not hinder the effect of the present invention, and may be 0mgKOH/g, but is preferably 1.2mgKOH/g or more from the viewpoint of improving the adhesion between the intermediate layer 2 and the active energy ray-curable adhesive layer 3 and the adhesion of the adhesive tape 10 for workpiece processing to the workpiece before irradiation with active energy rays, and is preferably 17.8mgKOH/g or less from the viewpoint of reducing the adhesion of the adhesive tape 10 for workpiece processing to the workpiece after irradiation with active energy rays. That is, the acid value is preferably in the range of 1.2mgKOH/g to 17.8 mgKOH/g.
Further, the hydroxyl value of the (meth) acrylate copolymer (A2) is not particularly limited as long as it is within a range that does not hinder the effect of the present invention, and is preferably within a range of 10.2mgKOH/g to 79.2mgKOH/g from the viewpoints of the adhesion between the intermediate layer 2 and the active energy ray-curable adhesive layer 3, the improvement of the cohesive force of the adhesive layer 3, and the control of the adhesive force of the adhesive tape 10 for workpiece processing to the workpiece before and after the active energy ray irradiation.
Further, the carbon-carbon double bond concentration of the (meth) acrylate copolymer (A2) (the carbon-carbon double bond equivalent per 1g of the solid content of the (meth) acrylate copolymer (A2)) is not limited as long as it is a concentration at which a sufficient effect of reducing the adhesive force is obtained in the adhesive layer 3 after irradiation with active energy rays, and it is not always the same depending on the use conditions such as the irradiation amount of active energy rays, but the carbon-carbon double bond concentration is preferably in the range of 0.59meq/g to 1.60meq/g, more preferably in the range of 0.59meq/g to 1.49meq/g, particularly preferably in the range of 0.59meq/g to 1.29meq/g, from the viewpoint of balance between the effect and economy. When the carbon-carbon double bond concentration is less than 0.59meq/g, the effect of reducing the adhesive force in the adhesive layer 3 after irradiation with active energy rays is small, and thus, when the work is peeled from the adhesive tape 10 for work processing, peeling becomes difficult, and there is a concern that defects such as breakage of the work to be processed increase. On the other hand, in the case where the carbon-carbon double bond concentration exceeds 1.60meq/g, the effect thereof becomes saturated gradually, and thus it is not preferable from the viewpoint of economy. In addition, depending on the copolymerization composition of the (meth) acrylate copolymer (A2), gelation is likely to occur during the addition reaction, and synthesis may be difficult in some cases; the adhesion between the intermediate layer 2 and the active energy ray-curable adhesive layer 3 becomes insufficient. In addition, when the carbon-carbon double bond concentration of the (meth) acrylate copolymer (A2) is confirmed, for example, the carbon-carbon double bond concentration can be calculated by measuring the iodine value of the (meth) acrylate copolymer (A2).
[ Cross-linking agent ]
In order to increase the molecular weight of the (meth) acrylate copolymer (A2) and to improve the cohesive force of the adhesive layer 3, the adhesive composition constituting the active energy ray-curable adhesive layer 3 of the present embodiment contains a crosslinking agent capable of reacting with the functional group of the (meth) acrylate copolymer (A2). The crosslinking agent is not particularly limited, and a known crosslinking agent having a functional group capable of reacting with a functional group of the (meth) acrylate copolymer (A2), that is, typically a hydroxyl group, a carboxyl group introduced as needed, or the like can be used. Specifically, examples thereof include polyisocyanate-based crosslinkers, epoxy-based crosslinkers, metal chelate-based crosslinkers, aziridine-based crosslinkers, melamine-resin-based crosslinkers, urea-resin-based crosslinkers, acid anhydride compound-based crosslinkers, polyamine-based crosslinkers, and carboxyl-containing polymer-based crosslinkers. Among these, from the viewpoints of reactivity and versatility, a polyisocyanate-based crosslinking agent, an epoxy-based crosslinking agent, or a metal chelate-based crosslinking agent is preferably used, and a polyisocyanate-based crosslinking agent is more preferably used. These crosslinking agents can be used alone, or 2 or more kinds can be used in combination. The amount of the crosslinking agent to be blended is preferably in the range of 0.01 to 10.0 parts by mass, more preferably in the range of 0.1 to 5.0 parts by mass, and particularly preferably in the range of 0.2 to 1.0 part by mass, based on 100 parts by mass of the solid content of the (meth) acrylate copolymer (A2).
The polyisocyanate-based crosslinking agent and the epoxy-based crosslinking agent may be the same as those exemplified as the crosslinking agent of the intermediate layer 2. The metal chelate-based crosslinking agent is preferably a crosslinking agent capable of crosslinking hydroxyl groups, and specifically, titanium chelate compounds having Ti as a center metal, zirconium chelate compounds having Zr as a center metal, and the like are exemplified.
Among the above-mentioned crosslinking agents, polyisocyanate-based crosslinking agents such as polyisocyanate compounds having an isocyanurate ring, adduct polyisocyanate compounds obtained by reacting trimethylolpropane with hexamethylene diisocyanate, and adduct polyisocyanate compounds obtained by reacting trimethylolpropane with toluene diisocyanate can be suitably used.
In the present embodiment, for example, when a (meth) acrylate copolymer containing n-butyl acrylate (n-BA) and 2-hydroxyethyl acrylate (2-HEA) is used as the base polymer of the (meth) acrylate copolymer (A2) and the polyisocyanate-based crosslinking agent is used as the crosslinking agent, the ratio of equivalent weight (NCO) of isocyanate groups (NCO) contained in the polyisocyanate-based crosslinking agent to hydroxyl groups (OH) contained in the (meth) acrylate copolymer (A2) having a photosensitive carbon-carbon double bond introduced into the side chain is preferably not less than 0.005 and not more than 0.338 from the viewpoints of the cohesive force of the adhesive layer 3, the adhesion between the intermediate layer 2 and the active energy ray-curable adhesive layer 3, and the control of the adhesive force, as described later, as long as the effect of the present invention is not impaired. From the same viewpoint, the residual hydroxyl group concentration in the whole adhesive composition (excluding the photopolymerization initiator) after the crosslinking reaction with the polyisocyanate-based crosslinking agent is preferably in the range of 0.04 to 1.62mmol/g, and further the carbon-carbon double bond concentration is preferably in the range of 0.58 to 1.48 meq/g.
[ photopolymerization initiator ]
The adhesive composition constituting the active energy ray-curable adhesive layer 3 of the present embodiment contains a photopolymerization initiator that generates radicals by irradiation with active energy rays. The photopolymerization initiator generates radicals upon irradiation of active energy rays to the adhesive composition constituting the active energy ray-curable adhesive layer 3, and initiates a crosslinking reaction of the photosensitive carbon-carbon double bonds introduced into the side chains of the (meth) acrylate copolymer (A2).
The photopolymerization initiator is not particularly limited, and conventionally known initiators can be used. Examples thereof include an alkyl benzophenone-based radical polymerization initiator, an acyl phosphine oxide-based radical polymerization initiator, and an oxime ester-based radical polymerization initiator. Examples of the alkyl benzophenone-based radical polymerization initiator include benzyl methyl ketal-based radical polymerization initiator, α -hydroxy alkyl benzophenone-based radical polymerization initiator, amino alkyl benzophenone-based radical polymerization initiator, and the like. Specific examples of the benzyl methyl ketal-based radical polymerization initiator include 2,2' -dimethoxy-1, 2-diphenylethan-1-one (for example, trade name: omnirad651, manufactured by IGM Resins B.V. Co.) and the like. Specific examples of the α -hydroxyalkylphenone radical polymerization initiator include 2-hydroxy-2-methyl-1-phenylpropane-1-one (trade name: omnirad1173, manufactured by IGM Resins b.v. company), 1-hydroxycyclohexylphenyl ketone (trade name: omnirad184, manufactured by IGM Resins b.v. company), 1- [4- (2-hydroxyethoxy) phenyl ] -2-hydroxy-2-methyl-1-propan-1-one (trade name: omnirad2959, manufactured by IGM Resins b.v. company), 2-hydroxy-1- {4- [4- (2-hydroxy-2-methylpropanoyl) benzyl ] phenyl } -2-methylpropan-1-one (trade name: omnirad127, manufactured by IGM Resins b.v. company), and the like. Specific examples of the aminoalkyl phenone-based radical polymerization initiator include 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropane-1-one (trade name: omnirad907, manufactured by IGM Resins B.V. Co.) and 2-benzyl methyl 2-dimethylamino-1- (4-morpholinophenyl) -1-butanone (trade name: omnirad369, manufactured by IGM Resins B.V. Co.) and the like. Specific examples of the acylphosphine oxide-based radical polymerization initiator include 2,4, 6-trimethylbenzoyl diphenyl phosphine oxide (trade name: omnirad TPO, manufactured by IGM Resins B.V. Co., ltd.), bis (2, 4, 6-trimethylbenzoyl) phenyl phosphine oxide (trade name: omnirad819, manufactured by IGM Resins B.V. Co., ltd.), and (2E) -2- (benzoyloxyimino) -1- [4- (phenylthio) phenyl ] octane-1-one (trade name: omniradOXE-01,IGM Resins B.V, manufactured by Co., ltd.) and the like. These photopolymerization initiators may be used alone, and 2 or more kinds may be used in combination.
The amount of the photopolymerization initiator to be added is preferably in the range of 0.1 to 10.0 parts by mass based on 100 parts by mass of the solid content of the (meth) acrylate copolymer (A2) having a photosensitive carbon-carbon double bond introduced into the side chain. When the amount of the photopolymerization initiator to be added is less than 0.1 part by mass, the photoreactivity with respect to the active energy ray is insufficient, and therefore, even if the active energy ray is irradiated, the photo radical crosslinking reaction of the (meth) acrylate copolymer (A2) does not proceed sufficiently, and as a result, the effect of reducing the adhesive force in the adhesive layer 3 after the irradiation of the active energy ray becomes small, and when the work is peeled from the adhesive tape 10 for work processing, peeling becomes difficult, and there is a concern that defects such as breakage of the work to be processed increase. On the other hand, when the amount of the photopolymerization initiator added exceeds 10.0 parts by mass, the effect is saturated and is not preferable from the viewpoint of economy. Further, depending on the kind of photopolymerization initiator, the adhesive layer 3 may yellow and may have poor appearance.
In addition, a compound such as dimethylaminoethyl methacrylate or isoamyl 4-dimethylaminobenzoate may be added to the adhesive composition as a sensitizer for such a photopolymerization initiator.
[ others ]
The adhesive composition constituting the active energy ray-curable adhesive layer 3 of the present embodiment may further contain additives such as a polyfunctional acrylic monomer, a polyfunctional acrylic oligomer, a tackifier, a filler, an anti-aging agent, a colorant, a flame retardant, an antistatic agent, a surfactant, a silane coupling agent, and a leveling agent, as necessary, within a range that does not impair the effects of the present invention.
[ thickness ]
The thickness of the active energy ray-curable adhesive layer 3 is not particularly limited as long as it does not hinder the effect of the present invention, and is preferably 5 μm or more from the viewpoints of the adhesion between the intermediate layer 2 and the adhesive layer 3, the improvement of the adhesive force of the adhesive tape 10 for workpiece processing to the workpiece before the irradiation of active energy rays, and the reduction of the adhesive force after the irradiation of active energy rays, for example, from the viewpoint of the application and drying of a solution of the adhesive composition of the adhesive layer 3, and preferably 150 μm or less, as long as it is appropriately adjusted according to the processing of the workpiece. That is, the thickness of the adhesive layer 3 is preferably in the range of 5 μm to 150 μm, more preferably in the range of 8 μm to 50 μm.
(adhesive tape for workpiece processing)
The adhesive tape 10 for work processing of the present embodiment has a structure comprising, in order, a base film 1 formed of a polyester resin composition, an intermediate layer 2, and an active energy ray-curable adhesive layer 3. The pressure-sensitive adhesive layer 3 is usually provided with a release liner on the side opposite to the side where the intermediate layer 2 is in contact. The release liner is not particularly limited, and examples thereof include synthetic resins such as polyethylene, polypropylene, and polyethylene terephthalate; paper, and the like. In order to improve the releasability from the adhesive layer 3, a release treatment using a silicone release treatment agent, a long-chain alkyl release treatment agent, a fluorine release treatment agent, or the like may be performed on the surface of the release liner. The thickness of the release liner is not particularly limited, and a release liner in a range of 10 μm to 200 μm can be suitably used.
The method for producing the adhesive tape 10 for processing a workpiece is not particularly limited, and, for example, the following method can be used. First, a base film 1 formed of a polyester resin composition is prepared. Next, a solution of the resin composition for the intermediate layer 2, which is a material for forming the intermediate layer 2, was prepared. The solution of the resin composition can be produced, for example, by uniformly mixing and stirring the (meth) acrylate copolymer (A1), the crosslinking agent, and the diluting solvent, which are constituent components of the intermediate layer 2. As the solvent, for example, a general-purpose organic solvent such as toluene or ethyl acetate can be used.
Next, the resin composition solution for the intermediate layer 2 is applied to the base film 1, and dried to form the intermediate layer 2 having a predetermined thickness. The coating method is not particularly limited, and for example, a die coater, a corner-cut wheel coater (registered trademark), a gravure coater, a roll coater, a reverse coater, or the like can be used for coating. The drying conditions are not particularly limited, and are preferably, for example, those in which the drying temperature is 80 ℃ to 150 ℃ and the drying time is 0.5 minutes to 5 minutes. Next, the release-treated surface side of the release liner was bonded to the exposed surface of the intermediate layer 2 formed on the base film 1.
Next, a release liner was prepared, and a solution of an adhesive composition for the adhesive layer 3 was prepared as a material for forming the adhesive layer 3. The solution of the adhesive composition can be prepared, for example, by uniformly mixing and stirring the (meth) acrylate copolymer (A2), the crosslinking agent, the photopolymerization initiator, and the diluting solvent, which are constituent components of the adhesive layer 3. As the solvent, for example, a general-purpose organic solvent such as toluene or ethyl acetate can be used.
Next, the adhesive composition solution for the adhesive layer 3 was used, and the release-treated surface side of the release liner was coated with the adhesive composition solution and dried to form the adhesive layer 3 having a predetermined thickness. The coating method is not particularly limited, and the coating can be performed by the same method as the intermediate layer 2. The drying conditions are not particularly limited, and can be performed under the same conditions as those of the intermediate layer 2. Then, the surface of the release liner having the intermediate layer 2 formed on the previously produced base film 1 peeled off was bonded to the exposed surface of the adhesive layer 3 formed on the release-treated surface side of the release liner, thereby producing a laminate.
Finally, the laminate is aged, for example, at 40 ℃ for 72 hours, and the (meth) acrylate copolymer of the intermediate layer 2 and the adhesive layer 3 is reacted with a crosslinking agent to crosslink and cure the laminate. By the above steps, the adhesive tape 10 for work processing, which is provided with the intermediate layer 2, the active energy ray-curable adhesive layer 3, and the release liner in this order from the substrate film side, on the substrate film 1 formed of the polyester resin composition can be produced. The intermediate layer 2 and the adhesive layer 3 may be aged separately and then bonded to each other to form a laminate. In the present invention, a laminate having a release liner on the adhesive layer 3 is also treated as the adhesive tape 10 for work processing.
As other methods of the method of manufacturing the adhesive tape 10 for processing a workpiece, the following methods are exemplified. First, a base film 1 formed of a polyester resin composition is prepared. Next, a solution of the resin composition for the intermediate layer 2, which is a material for forming the intermediate layer 2, and a solution of the adhesive composition for the adhesive layer 3, which is a material for forming the adhesive layer 3, are prepared. Next, using a die coater having 2 discharge ports, the above solutions were simultaneously extruded, coated and dried on the base film 1 in the order of the intermediate layer 2 and the adhesive layer 3 from the base film side by wet on wet coating, to form the intermediate layer 2 and the adhesive layer 3 having predetermined thicknesses. Then, a release-treated side of the release liner was bonded to the exposed surface of the adhesive layer 3 to form a laminate.
Finally, the laminate is aged for 72 hours, for example, at 40 ℃, and the (meth) acrylate copolymer of the intermediate layer 2 and the adhesive layer 3 is reacted with a crosslinking agent to crosslink and cure the laminate. By the above steps, the adhesive tape 10 for work processing, which is provided with the intermediate layer 2, the active energy ray-curable adhesive layer 3, and the release liner in this order from the substrate film side, on the substrate film 1 formed of the polyester resin composition, can be produced.
In the adhesive tape 10 for workpiece processing, the total thickness of the intermediate layer 2 and the active energy ray-curable adhesive layer 3 is not particularly limited as long as the effect of the present invention is not impaired, and the total thickness is appropriately adjusted according to the processing of the workpiece, and is preferably in the range of 10 μm to 300 μm, more preferably in the range of 13 μm to 150 μm. More specifically, for example, in the case of cutting a brittle work such as the glass substrate 30 or a hard work such as the sapphire glass substrate, the sum of the thicknesses is preferably in the range of 13 μm to 40 μm. In the case of polishing a semiconductor wafer having a circuit formed on the surface, for example, the total thickness is preferably 20 μm to 135 μm.
The adhesive tape 10 for workpiece processing needs to have a high initial adhesive force that can be firmly held and fixed so that the workpiece on the active energy ray-curable adhesive layer 3 does not move during workpiece processing. On the other hand, after the completion of the predetermined processing, the active energy ray-curable adhesive layer 3 needs to be cured and shrunk by irradiation with active energy rays so that the workpiece to be processed can be easily peeled off from the adhesive tape 10 for workpiece processing, and the adhesive force thereof is greatly reduced.
Examples of the active energy ray include ultraviolet rays, visible rays, infrared rays, electron rays, beta rays, and gamma rays. At these active energy raysAmong them, ultraviolet (UV) and Electron Beam (EB) are preferable, and Ultraviolet (UV) is particularly preferable. The light source for irradiating the Ultraviolet (UV) rays is not particularly limited, and for example, a black light lamp, an ultraviolet fluorescent lamp, a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a carbon arc lamp, a metal halide lamp, a xenon lamp, or the like can be used. In addition, arF excimer laser, krF excimer laser, excimer lamp, synchrotron radiation light, or the like can also be used. The amount of the Ultraviolet (UV) irradiation is not particularly limited, but is preferably 100mJ/cm, for example 2 Above 2,000mJ/cm 2 The following range is more preferably 300mJ/cm 2 Above 1,000mJ/cm 2 The following ranges.
The adhesive force (initial adhesive force) of the adhesive tape 10 for processing a work piece before irradiation with ultraviolet rays to a glass plate is preferably in the range of 5.0N/25mm to 26.0N/25mm, more preferably in the range of 19.0N/25mm to 25.0N/25 mm. When the adhesion force of the glass plate before ultraviolet irradiation is less than 5.0N/25mm, for example, when cutting the glass substrate 30, it becomes difficult to hold and fix the glass substrate 30 to the adhesive layer 3 of the adhesive tape 10 for work processing, and therefore, there is a concern that scattering and positional displacement of the glass chip 30a, defects of the glass chip 30a due to the positional displacement, and the like cannot be sufficiently suppressed. On the other hand, if the adhesion force before ultraviolet irradiation to the glass plate exceeds 25.0N/25mm, the glass chip 30a is excessively firmly held on the adhesive layer 3, and therefore, there is a concern that the adhesion force of the adhesive tape 10 for work processing after ultraviolet irradiation is not sufficiently lowered, and the glass chip 30a cannot be picked up satisfactorily.
The adhesive force of the adhesive tape 10 for processing a work to the glass plate after irradiation with ultraviolet rays is preferably in the range of 0.01N/25mm to 0.5N/25mm, more preferably in the range of 0.02N/25mm to 0.25N/25 mm. In the case where the adhesive force of the work processing adhesive tape 10 after irradiation with ultraviolet rays to the glass plate is smaller than 0.01N/25mm, for example, in a stage from after cutting the glass substrate 30 until picking up the glass chip 30a from the work processing adhesive tape 10, the glass chip 30a may be unintentionally peeled off from the work processing adhesive tape 10 or offset, and thus may not be picked up well. On the other hand, in the case where the adhesion force after ultraviolet irradiation to the glass plate exceeds 0.5N/25mm, for example, when the glass chips 30a are picked up individually, there is a concern that the glass chips 30a are broken and cannot be picked up satisfactorily because the decrease in adhesion force is insufficient. Further, even if pickup is possible, there is a concern that paste residue may occur.
In addition, the adhesive force in the present invention is set to be that by following JIS Z0237: the obtained adhesive force (N/25 mm) was measured by a 180 ° peel method of 2009, and details of the measurement method are described in the test method described below. The adhesive force after ultraviolet irradiation was 75mW/cm from the side of the base film 1 of the adhesive tape 10 for work processing, and a high-pressure mercury lamp was used as a light source 2 The cumulative light quantity was 300mJ/cm 2 The obtained adhesive force was measured by irradiating Ultraviolet (UV) light having a center wavelength of 365 nm.
Further, the adhesion (initial adhesion) of the adhesive tape 10 for workpiece processing to a stainless steel plate (SUS 304BA plate) before ultraviolet irradiation is preferably in the range of 5.0N/25mm or more and 26.0N/25mm or less, more preferably in the range of 19.0N/25mm or more and 25.0N/25mm or less. When the adhesion force of the stainless steel plate (SUS 304BA plate) before ultraviolet irradiation is less than 5.0N/25mm, for example, when cutting the glass substrate 30, the load of the cutting blade 40 and the washing water and the water pressure cannot be endured, and the work processing adhesive tape 10 may be peeled off or offset from the SUS ring frame 20. Further, for example, when polishing the semiconductor wafer 50, polishing water may intrude into the interface between the semiconductor wafer 50 and the adhesive layer 3. On the other hand, in the case where the adhesion force before ultraviolet irradiation to the above-mentioned stainless steel plate (SUS 304BA plate) exceeds 25.0N/25mm, for example, in the cutting process of the workpiece, the ring frame 20 made of SUS is excessively firmly held and fixed on the adhesive layer 3, and therefore, when the unnecessary adhesive tape 10 for workpiece processing is peeled off from the ring frame after the required process, there is a concern that the adhesive layer 3 is transferred to the ring frame made of SUS. In addition, in the polishing step of the semiconductor wafer 50, since the semiconductor wafer 50 is excessively firmly held and fixed on the adhesive layer 3, there is a concern that the adhesive force of the adhesive tape 10 for work processing after irradiation of ultraviolet rays is not sufficiently lowered, and when the adhesive tape 10 for work processing is peeled from the thinned semiconductor wafer 50 'after polishing, the adhesive layer 3 may be transferred or paste may remain on the surface of the thinned semiconductor wafer 50'.
Further, the adhesion of the adhesive tape 10 for processing a workpiece to a stainless steel plate (SUS 304BA plate) after irradiation with ultraviolet rays is preferably in the range of 0.01N/25mm to 0.5N/25mm, more preferably in the range of 0.02N/25mm to 0.25N/25 mm. When the adhesion of the adhesive tape 10 for workpiece processing to the stainless steel plate (SUS 304BA plate) after irradiation with ultraviolet rays is in the above-described range, for example, when the adhesive tape 10 for workpiece processing is peeled from the thinned semiconductor wafer 50' after polishing of the semiconductor wafer 50, the adhesive layer 3 can be easily peeled without transferring or leaving a paste on the surface of the thinned semiconductor wafer 50' and without damaging the thinned wafer 50 '.
As described above, according to the adhesive tape 10 for processing a workpiece of the present invention, since the base film 1 and the active energy ray-curable adhesive layer 3 formed of the polyester resin composition are well adhered by the intermediate layer 2 in a state before and after irradiation with active energy rays, for example, even when used as a back surface polishing tape for extremely thinning a semiconductor wafer, the active energy ray-curable adhesive layer can be peeled without being transferred to the semiconductor wafer at the time of peeling, and can be peeled from the ring frame in a process even when used as a dicing tape for cutting a brittle workpiece such as a glass substrate or a hard workpiece such as a sapphire glass substrate, and can be peeled without paste residue at the time of peeling from the ring frame, not only excellent operability but also excellent processing quality of the workpiece can be provided. The adhesive tape 10 for processing a workpiece according to the present embodiment can be suitably used not only for semiconductor wafers and optical members, but also for processing and transporting workpieces such as ceramics and other members for electronic devices.
Examples
The present invention will be described in more detail below with reference to examples and comparative examples. The present invention is not limited to the following examples.
1. Preparation of solution of resin composition for intermediate layer
As a solution of the resin composition for the intermediate layer 2 of the adhesive tape 10 for work processing, solutions of the resin compositions (A1-a) to (A1-s) each containing the following (meth) acrylate copolymers (A1-a ') to (A1-s') were prepared.
First, as a copolymer monomer component for synthesizing these (meth) acrylate copolymers (A1), there is prepared:
methyl acrylate (MA, molecular weight: 86.04, homopolymer Tg:10 ℃ C.);
methacrylic acid (MAA, molecular weight: 86.06: homopolymer Tg:228 ℃);
acrylic acid (AA, molecular weight: 72.06: homopolymer Tg:106 ℃ C.);
2-ethylhexyl acrylate (2-EHA, molecular weight: 184.3, homopolymer Tg: -70 ℃);
n-butyl acrylate (n-BA, molecular weight: 128.17, homopolymer Tg: -54 ℃);
ethyl acrylate (EA, molecular weight: 100.12, homopolymer Tg: -22 ℃);
2-hydroxyethyl acrylate (2-HEA, molecular weight: 116.12, homopolymer Tg: -15 ℃).
As a crosslinking agent, a TDI-based polyisocyanate crosslinking agent (trade name: CORONATE L-45E, solid content: 45 mass%, isocyanate group content in solution: 8.05 mass%, isocyanate group content in solid content: 17.89 mass%, number of calculated isocyanate groups: average 2.8/1 molecule, molecular weight: 656.64) manufactured by Tosoh Co., ltd was prepared.
(solution of resin composition (A1-a) for intermediate layer)
As the monomer components of the copolymer, 2-ethylhexyl acrylate (2-EHA), methyl Acrylate (MA) and methacrylic acid (MAA) were prepared. These copolymer monomer components were mixed so as to have a copolymerization ratio of 2-EHA/MA/maa=50 parts by mass/47 parts by mass/3 parts by mass (= 271.30mmol/546.26mmol/34.86 mmol), ethyl acetate was used as a solvent, azobisisobutyronitrile (AIBN) was used as an initiator, and a solution (solid content concentration: 35% by mass, weight average molecular weight Mw:40 ten thousand, solid content acid value: 19.6 mgKOH/g) of the (meth) acrylate copolymer (A1-a') was synthesized by solution radical polymerization. The Tg of the resulting (meth) acrylate copolymer (A1-a') was-34℃as calculated from the Fox formula.
Next, a TDI-based polyisocyanate-based crosslinking agent (trade name: CORONATE L-45E, solid content concentration: 45 mass%) as a crosslinking agent was blended in a ratio of 0.45 mass parts (0.20 mass parts in terms of solid content, 0.30 mmol) with respect to 286 mass parts (100 mass parts in terms of solid content) of the solution of the (meth) acrylate copolymer (A1-a'), and the resultant was diluted with ethyl acetate and stirred to prepare a resin composition (A1-a) for an intermediate layer 2 having a solid content concentration of 30 mass%.
(solutions of resin compositions (A1-b) to (A1-s) for intermediate layers)
The (meth) acrylate copolymers (A1-b ') to (A1-s ') were synthesized in the same manner by appropriately changing the copolymerization ratio of the copolymer monomer components and the copolymer monomer components as shown in tables 1 to 4 and 9, respectively, with respect to the (meth) acrylate copolymers (A1-a '). The glass transition temperatures (Tg), weight average molecular weights (Mw), solid acid values, and solid hydroxyl values of the synthesized (meth) acrylate copolymers (A1-b ') to (A1-s') are shown in tables 1 to 4 and 9, respectively. Next, using these solutions of (meth) acrylate copolymers, solutions of TDI-based polyisocyanate-based crosslinking agents (trade name: CORONATE L-45E, solid content: 45 mass%) as crosslinking agents, manufactured by Tosoh Co., ltd., were mixed in a ratio of 0.45 mass parts (solid content: 0.20 mass parts, 0.30 mmol) per 286 mass parts (solid content: 100 mass parts) of each of the solutions of (meth) acrylate copolymers (A1-b ') to (A1-s'), diluted with ethyl acetate, and stirred to prepare solutions of resin compositions (A1-b) to (A1-s) for intermediate layer 2 having a solid content of 30 mass%.
2. Preparation of solution of adhesive composition
As the adhesive composition for the active energy ray-curable adhesive layer 3 of the adhesive tape 10 for work processing, adhesive compositions (A2-a) to (A2-j) comprising (meth) acrylate copolymers (A2-a ') to (A2-j') each having a photosensitive carbon-carbon double bond introduced into a side chain of a (meth) acrylate copolymer Base Polymer (BP) comprising n-butyl acrylate (n-BA) as a main component of a copolymer monomer were synthesized.
First, as a copolymer monomer component for synthesizing the (meth) acrylic acid ester copolymer Base Polymer (BP) having n-butyl acrylate (n-BA) as a main component of the copolymer monomer, there is prepared:
methyl methacrylate (MMA, molecular weight: 100.12, homopolymer Tg:105 ℃);
n-butyl acrylate (n-BA, molecular weight: 128.17, homopolymer Tg: -54 ℃);
2-ethylhexyl acrylate (2-EHA, molecular weight: 184.3, tg: -70 ℃);
2-hydroxyethyl acrylate (2-HEA, molecular weight: 116.12, tg: -15 ℃);
methacrylic acid (MAA, molecular weight: 86.06: tg:228 ℃).
As a crosslinking agent, a TDI-based polyisocyanate crosslinking agent (trade name: CORONATE L-45E, solid content: 45 mass%, isocyanate group content in solution: 8.05 mass%, isocyanate group content in solid content: 17.89 mass%, number of calculated isocyanate groups: average 2.8/1 molecule, molecular weight: 656.64) manufactured by Tosoh Co., ltd was prepared.
(solution of adhesive composition (A2-a) for active energy ray-curable adhesive layer)
As the comonomer components, n-butyl acrylate (n-BA), 2-hydroxyethyl acrylate (2-HEA) and methacrylic acid (MAA) were prepared. These comonomer components were mixed so as to have a copolymerization ratio of n-BA/2-HEA/maa=76.8 parts by mass/20.2 parts by mass/3.0 parts by mass (= 599.20mmol/173.96mmol/34.86 mmol), ethyl acetate was used as a solvent, azobisisobutyronitrile (AIBN) was used as an initiator, and a solution of the (meth) acrylic acid ester copolymer base polymer (BP-a) having n-butyl acrylate (n-BA) as a main component of the copolymer monomer was synthesized by solution radical polymerization. The Tg of the resulting (meth) acrylate copolymer base polymer (BP-a) calculated from the Fox formula was-43 ℃.
Next, as an active energy ray-reactive compound produced by Showa electric Co., ltd., 2-isocyanatoethyl methacrylate (trade name: karenz MOI, molecular weight: 155.15, isocyanato: 1/1 molecule, double bond: 1/1 molecule) having isocyanate groups and active energy ray-reactive carbon-carbon double bonds was blended as an active energy ray-reactive compound produced by Showa electric Co., ltd.) in an amount of 10.0 parts by mass (64.45 mmol: 37.1mol% relative to the total mole number of 2-HEA) to 100 parts by mass of the (meth) acrylic acid ester copolymer base polymer, a solution (solid content: 40 mass%, weight average molecular weight Mw:60 ten thousand, solid content: 55.8mgKOH/g, solid content: 17.8mgKOH/g, carbon-carbon double bond content: 0.59 mmol) of the (meth) acrylic acid ester copolymer (A2-a') having a photosensitive carbon-carbon double bond introduced into the side chain was synthesized. In the above reaction, 0.05 parts by mass of hydroquinone monomethyl ether was used as a polymerization inhibitor for maintaining the reactivity of carbon-carbon double bonds.
Next, 250 parts by mass (100 parts by mass in terms of solid content) of a solution of the (meth) acrylic acid ester copolymer (A2-a') having a photosensitive carbon-carbon double bond in a side chain synthesized as described above was mixed with 1.52 parts by mass of an acylphosphine oxide photopolymerization initiator (trade name: omnirad 819) manufactured by igma Resins b.v. company, and 0.45 parts by mass (0.20 parts by mass in terms of solid content, 0.30 mmol) of a TDI-based polyisocyanate-based cross-linking agent (trade name: CORONATE L-45E, solid content: 45 mass%) manufactured by eastern co. The equivalent ratio (NCO/OH) of the isocyanate group (NCO) of the polyisocyanate-based crosslinking agent to the hydroxyl group (OH) of the (meth) acrylate copolymer (A2-a') having a photosensitive carbon-carbon double bond introduced into the side chain in the adhesive composition (A2-a) excluding the photopolymerization initiator was 0.007, the residual hydroxyl group concentration was 0.99mmol/g, and the carbon-carbon double bond content was 0.58mmol/g.
(solutions of adhesive compositions (A2-b) to (A2-j) for active energy ray-curable adhesive layers)
First, solutions of (meth) acrylate copolymer base polymers (BP-b) to (BP-j) were synthesized in the same manner by appropriately changing the copolymerization ratio of the copolymer monomer components and the copolymer monomer components with respect to the (meth) acrylate copolymer base polymer (BP-a) as shown in tables 4 to 6, respectively. Next, with respect to these (meth) acrylate copolymer base polymers (BP-b) to (BP-j), the addition reaction was carried out so that the amount of 2-isocyanate ethyl methacrylate (trade name: karenz MOI) as an active energy ray reactive compound was set to the amounts shown in tables 4 to 6, respectively, and solutions of (meth) acrylate copolymers (A2-b ') to (A2-j') each having a photosensitive carbon-carbon double bond introduced into the side chain were synthesized in the same manner. The glass transition temperatures (Tg) of the synthesized (meth) acrylate copolymer base polymers (BP-b) to (BP-j) and the weight average molecular weights (Mw), the solid content hydroxyl values, the solid content acid values, and the carbon-carbon double bond concentrations of the (meth) acrylate copolymers (A2-b ') to (A2-j') are shown in tables 4 to 6, respectively. Next, with respect to these (meth) acrylate copolymers (A2-b '), (A2-j') having a photosensitive carbon-carbon double bond introduced into the side chain, an acyl phosphine oxide photopolymerization initiator (trade name: omnirad 819) and a polyisocyanate-based crosslinking agent (trade name: CORONATE L-45E) were blended in accordance with tables 4 to 6, respectively, and diluted with ethyl acetate and stirred to prepare solutions of the adhesive compositions (A2-b) to (A2-j) for the adhesive layer 3 having a solid content of 30% by mass.
The equivalent ratio (NCO/OH), the residual hydroxyl group concentration, and the carbon-carbon double bond concentration of the hydroxyl groups (OH) of the (meth) acrylate copolymers (A2-b) to (A2-j) having the isocyanate groups (NCO) of the polyisocyanate-based crosslinking agent and the photosensitive carbon-carbon double bonds introduced into the side chains in the adhesive compositions (A2-b) to (A2-j) excluding the photopolymerization initiator are as follows.
·(A2-b)
(NCO/OH): 0.009, residual hydroxyl concentration: 0.99mmol/g, carbon-carbon double bond concentration: 0.58meq/g
·(A2-c)
(NCO/OH): concentration of residual hydroxyl groups of 0.023: 0.37mmol/g, carbon-carbon double bond concentration: 1.07meq/g
·(A2-d)
(NCO/OH): 0.020, residual hydroxyl concentration: 0.42mmol/g, carbon-carbon double bond concentration: 1.29meq/g
·(A2-e)
(NCO/OH): 0.016, residual hydroxyl concentration: 0.52mmol/g, carbon-carbon double bond concentration: 1.48meq/g
·(A2-f)
(NCO/OH): 0.047, residual hydroxyl concentration: 0.17mmol/g, carbon-carbon double bond concentration: 0.58meq/g
·(A2-g)
(NCO/OH): 0.005 residual hydroxyl concentration: 1.62mmol/g, carbon-carbon double bond concentration: 0.89meq/g
·(A2-h)
(NCO/OH): 0.338, residual hydroxyl concentration: 0.04mmol/g, carbon-carbon double bond concentration: 0.69meq/g
·(A2-i)
(NCO/OH): 0.015, residual hydroxyl concentration: 1.38mmol/g, carbon-carbon double bond concentration: 0.88meq/g
·(A2-j)
(NCO/OH): 0.216, residual hydroxyl concentration: 0.15mmol/g, carbon-carbon double bond concentration: 0.58meq/g
3. Production of adhesive tape 10 for workpiece processing
The structures of the base film 1, the intermediate layer 2, and the active energy ray-curable adhesive layer 3, and the like of the adhesive tapes 10 (a) to 10 (kk) for work processing manufactured in the above examples 1 to 31 and comparative examples 1 to 6 are shown in tables 1 to 10.
Example 1
As the base film 1, a polyethylene terephthalate (PET) film (trade name: emblet #100, thickness: 100 μm) manufactured by Unitika Co., ltd.) was used, and a solution of the resin composition (A1-a) for the intermediate layer was applied thereon so that the thickness of the intermediate layer 2 after drying became 10 μm, and the solvent was dried by heating at 100℃for 3 minutes, to form the intermediate layer 2 on the base film 1.
Next, the release liner (trade name: NS-38+A; material: polyethylene terephthalate, thickness: 38 μm) manufactured by Daiko Co., ltd.) was coated with the solution of the adhesive composition (A2-a) on the release treated surface side so that the thickness of the dried active energy ray-curable adhesive layer 3 became 10 μm, and the solution was heated at 100℃for 3 minutes to dry the solvent, and then the surface of the intermediate layer 2 formed on the base film 1 was bonded to the active energy ray-curable adhesive layer 3. Next, the adhesive tape for work processing 10 (a) was produced by crosslinking and curing the active energy ray-curable adhesive layer 3 at a temperature of 40 ℃ for 72 hours.
Examples 2 to 15
In the same manner as in example 1 except that the solutions of the resin compositions (A1-a) for the intermediate layer 2 were changed to the solutions of the resin compositions (A1-b) to (A1-o) for the intermediate layer 2 as shown in tables 1 to 4, the adhesive tapes 10 (b) to 10 (o) for work processing were produced.
Examples 16 to 24
Adhesive tapes 10 (p) to 10 (x) for work were produced in the same manner as in example 2 except that the solutions of the adhesive compositions (A2-a) for the active energy ray-curable adhesive layer 3 were changed to the solutions of the adhesive compositions (A2-b) to (A2-j) for the adhesive composition 3 as shown in tables 4 to 6, respectively, and the blending amounts of the crosslinking agents of the adhesive compositions were changed only for examples 22 to 24.
Examples 25 to 31
The same procedure as in example 2 was repeated except that the thickness of the intermediate layer 2 and the thickness of the active energy ray-curable adhesive layer 3 were set to the thicknesses shown in tables 7 and 8, respectively, to produce adhesive tapes 10 (y) to 10 (ee) for work processing.
Comparative examples 1 to 4
In the same manner as in example 1 except that the solutions of the resin compositions (A1-a) for the intermediate layer 2 were changed to the solutions of the resin compositions (A1-p) to (A1-s) for the intermediate layer 2 as shown in table 9, adhesive tapes 10 (ff) to 10 (ii) for work processing were produced.
Comparative example 5
A work-piece processing adhesive tape 10 (jj) was produced in the same manner as in example 1, except that the intermediate layer 2 was not provided, as shown in table 10.
Comparative example 6
The solution of the resin composition (A1-a) for the intermediate layer 2 was changed to the solution of the following resin composition: an adhesive tape 10 (kK) for processing a work was produced in the same manner as in example 1 except that 333.3 parts by mass (100 parts by mass in terms of solid content) of a solution having a solid content of 30% was prepared by dissolving an amorphous polyester resin (trade name: vylon 600, number average molecular weight Mn:16,000, tg:47 ℃, hydroxyl value: 7mgKOH/g, acid value: 2 mgKOH/g) manufactured by Toyo corporation in methyl ethyl ketone, and 13.3 parts by mass (10 parts by mass in terms of solid content, 15.66 mmol) of an HDI-based polyisocyanate-based crosslinking agent (trade name: CORONATE HL, solid content: 75% by mass, isocyanate group content in the solution: 12.8% by mass, isocyanate group content in the solid content: 17.07% by mass, calculated number of isocyanate groups: 2.6/1 molecule on average, molecular weight: 638.75) was blended in a ratio of 13.3 parts by mass (10 parts by mass in terms of solid content: 15.66 mmol) as a crosslinking agent.
4. Method for evaluating adhesive tape 10 for workpiece processing
The adhesive tapes 10 (a) to 10 (kk) for work processing manufactured in examples 1 to 31 and comparative examples 1 to 6 were evaluated for the adhesive force before and after irradiation with ultraviolet rays, the paste residue on an adherend, and the adhesion of the active energy ray-curable adhesive layer in the following manner.
4.1 measurement of adhesion before and after ultraviolet irradiation
The adhesive tapes 10 (a) to 10 (kk) for workpiece processing produced in examples and comparative examples were cut into long strips 150mm in length by 25mm in width, and measurement samples were produced. The MD direction of the adhesive tape 10 for workpiece processing (the coating direction of the intermediate layer 2 and the adhesive layer 3) is defined as the longitudinal direction of the measurement sample, and the direction perpendicular to this direction is defined as the width direction of the measurement sample. As an adherend, a glass plate and a stainless steel plate (SUS 304BA plate) were prepared, respectively. The release liner was peeled off from the adhesive tape 10 for work processing at a temperature of 23 ℃ and a humidity of 50%, the exposed surface of the adhesive layer 3 was overlapped on the surface of the adherend, and a 2kg roller was reciprocated 1 time, and the adhesive was applied with a load and left for 20 minutes. The length of the bonded portion was 80mm. Then, using a tensile tester, a tensile test was performed by following JIS Z0237: according to the 180 DEG peeling method of 2009, the adhesive tape 10 for work processing was peeled from an adherend at a peeling speed of 300mm/min and a peeling angle of 180 DEG, and the adhesive force (unit: N/25 mm) was measured. The number of samples for measurement was 3, and the average value of 3 measurements was the adhesion before Ultraviolet (UV) irradiation.
In the same manner as described above, the adhesive tape 10 for work processing manufactured in examples and comparative examples was attached to an adherend, left for 20 minutes, and then, from the side of the base film 1 of the adhesive tape 10 for work processing, ultraviolet (UV) light having a center wavelength of 365nm was irradiated with a high-pressure mercury lamp, thereby curing the adhesive layer 3. The ultraviolet irradiation conditions were set to irradiation intensities: 75mW/cm 2 Cumulative light amount: 300mJ/cm 2 . Then, the adhesion (unit: N/25 mm) was measured in the same manner as described above, and the average of 3 measurements was set as the adhesion after Ultraviolet (UV) irradiation.
4.2 evaluation of paste residue
The surface of the adherend after the measurement of the adhesion was visually observed, and the presence or absence of the paste residue was evaluated. Regarding the glass plate, the surface after measurement of the adhesion after ultraviolet irradiation was observed. This is an evaluation of the paste residue on the surface of the glass chip 30a when the glass chip 30a is picked up from the work processing adhesive tape 10 irradiated with ultraviolet rays after the dicing of the glass substrate 30.
Further, regarding the stainless steel plate (SUS 304BA plate), the surface after the measurement of the adhesion before and after the ultraviolet irradiation was performed was observed. The former (before ultraviolet irradiation) is an evaluation of paste residue on the surface of the ring frame 20 when the outer edge portion of the adhesive tape 10 for workpiece processing, which is not irradiated with Ultraviolet (UV), is peeled from the ring frame 20 after the end of the dicing step. The latter (after ultraviolet irradiation) 9 is an evaluation of paste residue on the surface of the semiconductor wafer 50 'when the ultraviolet-irradiated adhesive tape 10 for workpiece processing is peeled from the thinned semiconductor wafer 50' after polishing the semiconductor wafer 50.
The paste residue was evaluated according to the following criteria. Evaluation of the evaluation was judged to be practically no problem.
Evaluation criterion
-following: no paste residue
X: with paste residue
4.3 evaluation of adhesion (Cross-hatch test) of active energy ray-curable adhesive layer
First, ultraviolet (UV) light having a center wavelength of 365nm was irradiated from the side of the base film 1 of the adhesive tape 10 for workpiece processing manufactured in examples and comparative examples using a high-pressure mercury lamp, and the adhesive layer 3 was cured. The ultraviolet irradiation conditions were set to irradiation intensities: 75mW/cm 2 Cumulative light amount: 300mJ/cm 2 . Then, the release liner was peeled off from the adhesive tape 10 for workpiece processing, based on JIS K5600-5-6: 1999, a lattice-like incision is applied from the surface of the adhesive layer 3. The number of cuts in each direction of the lattice pattern was 10, and the intervals between cuts were 1mm, so that a lattice grid of 100 lattices was formed. After a film base material adhesive tape (trade name: no.626050 film tape Maxel Co., ltd.; 180 DEG peel adhesion to SUS304BA plate: 10.8N/25 mm) was adhered to the lattice grids formed, the number of grids peeled by the adhesive layer 3 at the time of manual peeling was counted to evaluate the intermediate layer 2 and the active energy ray-curable adhesive layer 3 Is used for the adhesion of the resin composition. In addition, without the intermediate layer 2, the adhesion between the base film 1 and the active energy ray-curable adhesive layer 3 was evaluated. This evaluation is an evaluation of the paste residue on the surface of the semiconductor wafer 50 'when the work processing adhesive tape 10 irradiated with ultraviolet rays is peeled from the thinned semiconductor wafer 50' at a high speed after polishing the semiconductor wafer 50. That is, if the adhesion is good, even if the adhesive tape 10 for processing a workpiece irradiated with ultraviolet rays is peeled at a high speed, no paste remains on the surface of the thinned semiconductor wafer 50'.
In the case where the Ultraviolet (UV) light is not irradiated to the adhesive tape 10 for workpiece processing, that is, in the state before Ultraviolet (UV) light irradiation, the adhesion between the intermediate layer 2 and the active energy ray-curable adhesive layer 3 was evaluated based on the above-described dicing method. This evaluation is assumed to be an evaluation of paste residue on the surface of the ring frame 20 when the outer edge portion of the work processing adhesive tape 10, which is not irradiated with Ultraviolet (UV), is peeled off from the ring frame 20 at a high speed after the cutting process is completed, for example, when the work processing adhesive tape attached to the ring frame 20 is pressed and peeled off from the center portion of the tape with a hand. That is, if the adhesion is good, even if the outer edge portion of the work processing adhesive tape 10, which is not irradiated with Ultraviolet (UV), is peeled off from the ring frame 20 at a high speed, no paste remains on the surface of the thinned semiconductor wafer 50'.
The adhesion was evaluated according to the following criteria. Evaluation of the evaluation was judged to be practically no problem.
-following: the number of meshes from which the adhesive layer was peeled was in the range of 0 (0/100) with respect to 100 meshes
X: the number of the meshes from which the adhesive layer is peeled is in the range of 1 to 100 (1/100 to 100/100) with respect to 100 meshes
5. Evaluation results
The results of the physical property evaluations of the adhesive tapes 10 (a) to 10 (kk) for workpiece processing produced in examples 1 to 31 and comparative examples 1 to 6 are shown in tables 11 to 20.
TABLE 1
TABLE 1 construction of adhesive tape
TABLE 2
TABLE 2 construction of adhesive tape
TABLE 3
TABLE 3 construction of adhesive tape
TABLE 4
TABLE 4 construction of adhesive tape
TABLE 5
TABLE 5 construction of adhesive tape
TABLE 6
TABLE 6 construction of adhesive tape
TABLE 7
TABLE 7 construction of adhesive tape
TABLE 8
TABLE 8 construction of adhesive tape
TABLE 9
TABLE 9 construction of adhesive tape
TABLE 10 construction of adhesive tape
TABLE 11
Table 11 physical properties of adhesive tape
TABLE 12
Table 12 physical properties of adhesive tape
TABLE 13
Table 13 physical properties of adhesive tape
TABLE 14
Table 14 physical properties of adhesive tape
TABLE 15
Table 15 physical properties of adhesive tape
TABLE 16
Table 16 physical properties of adhesive tape
TABLE 17
Table 17 physical properties of adhesive tape
TABLE 18
Table 18 physical properties of adhesive tape
TABLE 19
Table 19 physical properties of adhesive tape
TABLE 20
Table 20 physical properties of adhesive tape
First, as shown in tables 11 to 18, it was confirmed that the adhesive tapes 10 (a) to 10 (ee) for work processing of examples 1 to 31 satisfying the requirements of the present invention were excellent in all of the adhesion before and after irradiation with ultraviolet rays, the paste residue on an adherend, and the adhesion to an active energy ray-curable adhesive layer, even when a film formed of a polyester resin composition was used as a base film, in order to improve the processing quality of a work. That is, when the adhesive tape for work processing of the present invention is used as a back surface polishing tape for thinning a semiconductor wafer, it is determined that uniform thinning can be performed by polishing the semiconductor wafer, and when the back surface polishing tape is peeled after polishing is completed, the active energy ray-curable adhesive layer can be peeled without being transferred to the thinned semiconductor wafer. In addition, in the case of using the dicing tape as a dicing tape for cutting a brittle workpiece such as a glass substrate or a hard workpiece such as a sapphire glass substrate with high quality, it was determined that the dicing tape holding the workpiece was not peeled off from the ring frame in the dicing step, and the chip after dicing was also good in pick-up property, and when the dicing tape was peeled off from the ring frame after the pick-up was completed, the dicing tape could be peeled off without leaving a paste residue on the ring frame.
On the other hand, as shown in tables 19 and 20, it was confirmed that the adhesive tapes 10 (ff) to 10 (kk) for work processing of comparative examples 1 to 6 which did not satisfy the requirements of the present invention were at a level which was free from problems with respect to the adhesive force before and after irradiation with ultraviolet rays, but in any evaluation of the adhesive properties of the adhesive layer for curing the adhesive agent with active energy rays, the adhesive tapes were inferior to the adhesive tapes 10 (a) to 10 (ee) for work processing of examples 1 to 31.
Specifically, in the adhesive tapes 10 (ff) for workpiece processing of comparative example 1 and the adhesive tapes 10 (gg) for workpiece processing of comparative example 2, since the content ratio of methyl acrylate as the copolymer monomer component of the ternary (meth) acrylate copolymer (A1) of the intermediate layer 2 exceeds the upper limit value of the claims, the paste residue was observed on the surface of the stainless steel plate (SUS 304BA plate) in the evaluation of the paste residue before the ultraviolet irradiation. In addition, in the adhesive tapes 10 (gg) for workpiece processing of comparative example 2, in the evaluation of adhesion by the cross-cut test after the irradiation of ultraviolet rays, a large amount of peeling of the adhesive layer was confirmed as compared with the adhesive tapes 10 (a) to 10 (c) for workpiece processing of examples 1 to 3.
In the adhesive tapes 10 (hh) for workpiece processing of comparative example 3 and the adhesive tapes 10 (ii) for workpiece processing of comparative example 4, since the content ratio of methacrylic acid as the copolymer monomer component of the ternary (meth) acrylate copolymer (A1) of the intermediate layer 2 was lower than the lower limit value of the claims, in the evaluation of adhesion by the cross-cut test before ultraviolet irradiation, a considerable amount of peeling of the adhesive layers was confirmed as compared with the adhesive tapes 10 (b), 10 (d), 10 (f) and 10 (g) for workpiece processing of examples 2, 4, 6 and 7. In addition, in evaluation of paste residue before ultraviolet irradiation, paste residue was also observed on the surface of the stainless steel plate (SUS 304BA plate).
Further, since the adhesive tape 10 (jj) for workpiece processing of comparative example 5 did not include the intermediate layer 2, peeling (100/100) of the entire surface of the adhesive layer was observed in the evaluation of adhesion by the cross-cut test before ultraviolet irradiation.
Further, in the adhesive tape 10 (kk) for workpiece processing of comparative example 6, the amorphous polyester resin composition different from the present invention was used for the intermediate layer 2, but in the evaluation of adhesion by the cross-cut test before ultraviolet irradiation, extremely large peeling of the adhesive layer was observed.
Description of symbols
1 … substrate film
2 … interlayer
3 … active energy ray-curable adhesive layer
Adhesive tape for 10 … workpiece processing
11 … cutting tape
12 … stripping tape
20 … ring frame
30 … glass substrate
30a … glass chip (monolithic glass substrate)
40 … cutting scraper
50 … semiconductor wafer
50' … thinned semiconductor wafer
51 … circuit
60 … grinding machine (grinding wheel).

Claims (12)

1. An adhesive tape for processing a workpiece, comprising a base film formed of a polyester resin composition, an intermediate layer, and an active energy ray-curable adhesive layer in this order,
the intermediate layer is formed from a resin composition containing a (meth) acrylate copolymer (A1) containing methyl acrylate and methacrylic acid as copolymer monomer components,
when the total amount of the monomer components constituting the ternary or higher (meth) acrylate copolymer (A1) is 100 parts by mass, the methyl acrylate is contained in a range of 47 to 67 parts by mass, the methacrylic acid is contained in a range of 2 to 7 parts by mass,
the active energy ray-curable adhesive layer is formed from an adhesive composition containing: a (meth) acrylate copolymer (A2) having a photosensitive carbon-carbon double bond introduced into a side chain of a (meth) acrylate copolymer base polymer, and a crosslinking agent,
The (meth) acrylate copolymer base polymer contains n-butyl acrylate as a copolymer monomer component in a proportion of more than 50 parts by mass and 90 parts by mass or less, based on 100 parts by mass of the total amount of copolymer monomer components constituting the (meth) acrylate copolymer base polymer.
2. The adhesive tape for workpiece processing according to claim 1, wherein the ternary or higher (meth) acrylate copolymer (A1) is a ternary or higher (meth) acrylate copolymer comprising 2-ethylhexyl acrylate as a monomer component of a copolymer other than the methyl acrylate and the methacrylic acid.
3. The adhesive tape for workpiece processing according to claim 2, wherein the ternary or higher (meth) acrylate copolymer (A1) is a ternary (meth) acrylate copolymer comprising 2-ethylhexyl acrylate, methyl acrylate and methacrylic acid as comonomer components, and the content of the 2-ethylhexyl acrylate is adjusted to be 26 to 51 parts by mass, the content of the methyl acrylate is adjusted to be 47 to 67 parts by mass, and the content of the methacrylic acid is adjusted to be 2 to 7 parts by mass, so that the total amount of the copolymer monomer components becomes 100 parts by mass, based on 100 parts by mass of the total amount of the copolymer monomer components constituting the ternary (meth) acrylate copolymer (A1).
4. The adhesive tape for workpiece processing according to any one of claims 1 to 3, wherein the ternary or higher (meth) acrylate copolymer (A1) has a glass transition temperature in the range of-36 ℃ to-9 ℃.
5. The adhesive tape for workpiece processing according to any one of claims 1 to 4, wherein the (meth) acrylate copolymer base polymer is a ternary (meth) acrylate copolymer comprising n-butyl acrylate, 2-hydroxyethyl acrylate and methacrylic acid as copolymer monomer components, and wherein the n-butyl acrylate is in a range of 66 to 90 parts by mass, the 2-hydroxyethyl acrylate is in a range of 9.8 to 31 parts by mass, and the methacrylic acid is in a range of 0.2 to 3 parts by mass, and the total amount of the copolymer monomer components is adjusted to 100 parts by mass, based on 100 parts by mass of the total amount of the copolymer monomer components constituting the (meth) acrylate copolymer base polymer.
6. The adhesive tape for processing a workpiece according to any one of claims 1 to 5, wherein the glass transition temperature of the (meth) acrylate copolymer base polymer is in the range of-50 ℃ to-39 ℃.
7. The adhesive tape for workpiece processing according to any one of claims 1 to 6, wherein the thickness of the intermediate layer is 5 μm or more.
8. The adhesive tape for workpiece processing according to any one of claims 1 to 7, wherein the active energy ray-curable adhesive layer has a thickness of 5 μm or more.
9. The adhesive tape for workpiece processing according to any one of claims 1 to 8, wherein the sum of the thickness of the intermediate layer and the thickness of the active energy ray-curable adhesive layer is 10 μm or more.
10. The adhesive tape for processing a workpiece according to any one of claims 1 to 9, wherein the base film formed of the polyester resin composition is a polyethylene terephthalate film.
11. The adhesive tape for workpiece processing according to any one of claims 1 to 10, wherein the adhesive force before ultraviolet irradiation, i.e., the initial adhesive force, to a glass plate is in the range of 5.0N/25mm to 25.0N/25mm, and the adhesive force after ultraviolet irradiation is in the range of 0.01N/25mm to 0.50N/25 mm.
12. The adhesive tape for workpiece processing according to any one of claims 1 to 11, which has an initial adhesive force, i.e., an initial adhesive force, of 5.0N/25mm to 25.0N/25mm inclusive, before ultraviolet irradiation and an adhesive force of 0.01N/25mm to 1.0N/25mm inclusive, after ultraviolet irradiation, to a stainless steel plate, i.e., a SUS304BA plate.
CN202280025102.1A 2021-03-31 2022-01-17 Adhesive tape for processing workpiece Pending CN117157369A (en)

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JP3838637B2 (en) 2002-06-10 2006-10-25 日東電工株式会社 Glass substrate dicing adhesive sheet and glass substrate dicing method
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