CN115991962A - Piece for workpiece processing - Google Patents

Piece for workpiece processing Download PDF

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Publication number
CN115991962A
CN115991962A CN202210414885.4A CN202210414885A CN115991962A CN 115991962 A CN115991962 A CN 115991962A CN 202210414885 A CN202210414885 A CN 202210414885A CN 115991962 A CN115991962 A CN 115991962A
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China
Prior art keywords
mass
sheet
workpiece processing
layer
adhesive layer
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CN202210414885.4A
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Chinese (zh)
Inventor
梅本夏树
山口征太郎
渡边周平
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Lintec Corp
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Lintec Corp
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Publication of CN115991962A publication Critical patent/CN115991962A/en
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    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • 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
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J11/00—Features of adhesives not provided for in group C09J9/00, e.g. additives
    • C09J11/08—Macromolecular additives
    • 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

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Organic Chemistry (AREA)
  • General Physics & Mathematics (AREA)
  • Physics & Mathematics (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Manufacturing & Machinery (AREA)
  • Computer Hardware Design (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Power Engineering (AREA)
  • Adhesives Or Adhesive Processes (AREA)
  • Adhesive Tapes (AREA)
  • Dicing (AREA)
  • Laminated Bodies (AREA)

Abstract

The present invention provides a sheet for processing a workpiece, which has excellent antistatic property and pick-up property and excellent adhesion between an adhesive layer and a substrate. The sheet (1) for processing a workpiece comprises a base material (11) containing an antistatic agent and an adhesive layer (12) formed from an active energy ray-curable acrylic adhesive composition containing an acrylic polymer and a free epoxy resin, a slit is cut into the adhesive layer (12) by a dicing blade from the surface side of the adhesive layer (12) opposite to the base material (11), a dicing portion having a number of squares of 100 is formed by a JIS K5600-5-6:1999 dicing method such that the dicing distance is 5mm and the dicing line is 11×11, an adhesive Tape made of NICHIBAN Co., ltd. Cellulose Tape (registered trademark) is attached to the dicing portion, and the number of residual squares is 95 or more after the adhesive Tape attached to the dicing portion is peeled off.

Description

Piece for workpiece processing
Technical Field
The present invention relates to a workpiece processing sheet used for processing a workpiece such as a semiconductor wafer.
Background
In manufacturing a semiconductor device from a semiconductor wafer such as silicon or gallium arsenide, the semiconductor wafer as a workpiece is subjected to back grinding (back grinding) in a state of being attached to an adhesive sheet (hereinafter sometimes referred to as "workpiece processing sheet") having a base material and an adhesive layer, and then diced (dicing) into chips. After that, after washing, drying, expanding, and the like, the semiconductor chip is picked up from the work processing sheet and mounted on a predetermined substrate, a lead frame, or the like.
In each of the above steps, static electricity is generated by peeling, rubbing, contact, and the like at the time of peeling the release sheet from the adhesive layer of the work piece processing sheet, at the time of back grinding, at the time of cutting, at the time of cleaning, at the time of pickup, and the like. Such static electricity may cause damage to a semiconductor wafer, chips, circuits formed thereon, or the like, or cause adhesion of foreign matter such as dust.
Patent document 1 discloses an antistatic adhesive tape for semiconductor processing, which is composed of a base film and a photocurable adhesive layer, wherein the antistatic adhesive tape for semiconductor processing has an antistatic layer containing a conductive polymer on at least one surface of the base film and an adhesive layer containing a photocurable unsaturated carbon bond in a molecule of a base polymer on the antistatic layer.
Prior art literature
Patent literature
Patent document 1: japanese patent laid-open publication No. 2011-210944
Disclosure of Invention
Technical problem to be solved by the invention
As the adhesive layer of the work processing sheet, an adhesive layer composed of an active energy ray-curable adhesive is often used as in patent document 1. In general, an active energy ray-curable adhesive is cured by irradiation of active energy rays, and further the adhesive force is significantly reduced, and therefore, a semiconductor chip can be easily picked up by irradiation of active energy rays before the semiconductor chip is picked up.
In order to achieve the process of the Inline process, it is proposed to attach a workpiece processing sheet, which is a dicing sheet, to a semiconductor wafer immediately after back grinding. However, when the workpiece processing sheet is attached to the polishing surface of the semiconductor wafer immediately after back polishing, the adhesion is extremely high, and the adhesive force of the adhesive layer may not be sufficiently reduced even when the active energy rays are irradiated as described above. In this case, a problem arises in that a pick-up failure of the semiconductor chip occurs.
In order to solve the above problems, it is conceivable to add a component for reducing the adhesive force to the adhesive, but in this case, there is a problem that the adhesion between the adhesive layer and the substrate is lowered. If the adhesion between the adhesive layer and the substrate is reduced, the adhesive layer peels off from the substrate at the time of pickup and adheres to the chip side.
The present invention has been made in view of the above-described circumstances, and an object thereof is to provide a sheet for workpiece processing having antistatic properties, excellent in pick-up properties, and excellent in adhesion between an adhesive layer and a substrate.
Technical means for solving the technical problems
In order to achieve the above object, in a first aspect, the present invention provides a workpiece processing sheet comprising a base material and an adhesive layer laminated on one surface side of the base material, wherein the base material contains an antistatic agent, the adhesive layer is formed of an active energy ray-curable acrylic adhesive composition containing an acrylic polymer and a free epoxy resin, a slit is cut into the adhesive layer from a surface side of the adhesive layer opposite to the base material after active energy ray curing by a dicing blade, a dicing portion having a number of 100 squares is formed such that a dicing pitch is 5mm and a dicing line is 11×11 lines by a dicing method (cross cut) of JIS K5600-5-6:1999, an adhesive Tape made of a dicing Tape made of nichiband co., lcell td is attached to the dicing portion, and the number of residues remaining after the adhesive Tape attached to the dicing portion is peeled is 95 or more (invention 1).
In the invention (invention 1), the antistatic agent is contained in the base material to provide antistatic properties. In addition, by containing the free epoxy resin in the adhesive layer, the pickup property is excellent. In particular, even when the workpiece processing sheet is attached to a semiconductor wafer or the like immediately after back grinding, the adhesive force of the adhesive layer is sufficiently reduced after irradiation with active energy rays, and the chip can be easily picked up. In addition, by setting the number of squares in the checkerboard test by the dicing method to 95 or more, the adhesion between the adhesive layer and the substrate is excellent. This can prevent the adhesive layer from peeling from the substrate and adhering to the chip side at the time of picking up.
In the above invention (invention 1), it is preferable that: the surface resistivity of the surface of the adhesive layer opposite to the base material after the active energy ray curing was 1.0X10 13 Ω/≡is below (invention 2).
In the above inventions (inventions 1 and 2), it is preferable that: the content of the free epoxy resin in the acrylic adhesive composition is 5 parts by mass or more and less than 40 parts by mass with respect to 100 parts by mass of the acrylic polymer (invention 3).
In the above inventions (inventions 1 to 3), it is preferable that: the acrylic adhesive composition contains a crosslinking agent (invention 4).
In the above inventions (inventions 1 to 4), it is preferable that: the content of the crosslinking agent in the acrylic adhesive composition is 3 parts by mass or more per 100 parts by mass of the acrylic polymer (invention 5).
In the above inventions (inventions 4 and 5), it is preferable that: the cross-linking agent is toluene diisocyanate cross-linking agent (invention 6).
In the above inventions (inventions 1 to 6), it is preferable that: the acrylic polymer is a (meth) acrylate polymer having a functional group having active energy ray curability introduced into a side chain, and the (meth) acrylate polymer contains an alkyl (meth) acrylate having 1 to 4 carbon atoms in which the largest number of monomer units constituting the main chain of the polymer are alkyl groups (invention 7).
In the above inventions (inventions 1 to 7), it is preferable that: the substrate has a surface layer adjacent to the adhesive layer, a back layer distant from the adhesive layer, and an intermediate layer between the surface layer and the back layer, at least the surface layer containing an antistatic agent (invention 8).
In the above invention (invention 8), it is preferable that: the surface layer and the back surface layer contain an antistatic agent, the intermediate layer contains no antistatic agent, or the intermediate layer contains an antistatic agent in an amount of less than 5 mass% and less than the content of the antistatic agent in each of the surface layer and the back surface layer (unit: mass%) (invention 9).
In the above inventions (inventions 1 to 9), it is preferable that: the antistatic agent is a polymer type antistatic agent (invention 10).
The workpiece processing sheet of the above inventions (inventions 1 to 10) is preferably a dicing sheet (invention 11).
Effects of the invention
The sheet for workpiece processing of the present invention has excellent antistatic properties and also excellent pickup properties and adhesion of the adhesive layer to the substrate.
Drawings
Fig. 1 is a cross-sectional view of a workpiece processing sheet according to an embodiment of the present invention.
Description of the reference numerals
1: a workpiece processing sheet; 11: a substrate; 111: a surface layer; 112: an intermediate layer; 113: a back layer; 12: an adhesive layer.
Detailed Description
Hereinafter, embodiments of the present invention will be described.
The workpiece processing sheet of the present embodiment includes a base material and an adhesive layer laminated on one surface side of the base material. The base material contains an antistatic agent, and the adhesive layer is formed from an active energy ray-curable acrylic adhesive composition containing an acrylic polymer and a free epoxy resin. Then, a dicing blade was used to cut a slit from the surface side of the adhesive layer on the opposite side from the base material after curing with an active energy ray, a dicing portion having a number of squares of 100 was formed such that the dicing distance was 5mm and the dicing line was 11×11 pieces according to the dicing method of JIS K5600-5-6:1999, an adhesive Tape made of cellose Tape (registered trademark) manufactured by nichiba co., ltd was attached to the dicing portion, and the number of squares remaining after peeling the adhesive Tape attached to the dicing portion was 95 or more.
The workpiece processing sheet of the present embodiment has antistatic properties by incorporating an antistatic agent into a base material. Further, by containing the free epoxy resin in the adhesive layer, the pickup property is excellent. In particular, even when the workpiece processing sheet of the present embodiment is attached to a semiconductor wafer or the like immediately after back grinding, the adhesive force of the adhesive layer is sufficiently reduced after irradiation with active energy rays, and the chip can be easily picked up. Specifically, even if the push-up amount of the ejector pin (pin) or the ejector pin (needle) is reduced in a device such as a push-up chip separator (die ejector), the chip can be picked up. Thus, damage to the chip can be reduced. Further, the workpiece processing sheet of the present embodiment is excellent in adhesion between the adhesive layer and the substrate by setting the number of squares in the above-described checkered test by the above-described dicing method to 95 or more. This can prevent the adhesive layer from peeling from the substrate and adhering to the chip side at the time of picking up.
The number of squares measured by the dicing method is 95 or more, preferably 96 or more, more preferably 97 or more, particularly preferably 98 or more, further preferably 99 or more, and most preferably 100, from the viewpoint of adhesion between the adhesive layer and the substrate. The irradiation amount of the active energy ray to the adhesive layer is an irradiation amount at which the adhesive layer is sufficiently cured, and is specifically described in a test example described later.
1. Construction of sheet for workpiece processing
Fig. 1 shows a cross-sectional view of a workpiece processing sheet according to an embodiment of the present invention. The workpiece processing sheet 1 shown in fig. 1 includes a base material 11 and an adhesive layer 12 laminated on one surface side of the base material 11.
1-1 adhesive layer
The adhesive layer 12 in the present embodiment is formed of an active energy ray-curable acrylic adhesive composition containing an acrylic polymer and a free epoxy resin. Preferably, the acrylic adhesive composition further contains a crosslinking agent.
The active energy ray-curable acrylic pressure-sensitive adhesive composition may contain an energy ray-curable acrylic polymer as a main component, or may contain a mixture of a non-energy ray-curable acrylic polymer (an acrylic polymer having no energy ray-curability) and a monomer and/or oligomer having at least one or more energy ray-curable groups as a main component. The mixture of the energy ray-curable acrylic polymer and the non-energy ray-curable acrylic polymer may be a mixture of the energy ray-curable acrylic polymer and a monomer and/or oligomer having at least one or more energy ray-curable groups, or may be a mixture of 3 kinds of the above.
Among them, in the present embodiment, an acrylic polymer having active energy ray curability, which is liable to decrease in adhesion after irradiation with active energy rays, is preferably used. Specifically, the acrylic polymer is preferably an acrylic polymer having active energy ray curability, and more specifically, is preferably a (meth) acrylate polymer having a functional group having active energy ray curability introduced into a side chain (hereinafter, also referred to as "active energy ray curable polymer"). In the present specification, (meth) acrylate means both acrylate and methacrylate. Other similar terms are also the same. In addition, "polymer" also includes the concept of "copolymer".
(1) Each component is composed of
(1-1) active energy ray-curable Polymer
The active energy ray-curable polymer is preferably obtained by reacting an acrylic polymer having a monomer unit containing a functional group with an unsaturated group-containing compound having a functional group bonded to the functional group.
The acrylic polymer preferably contains a structural unit derived from a functional group-containing monomer and a structural unit derived from a (meth) acrylate or a derivative thereof.
The functional group-containing monomer of the structural unit of the acrylic polymer is preferably a monomer having a polymerizable double bond and a functional group such as a hydroxyl group, a carboxyl group, an amino group, a substituted amino group, or an epoxy group in the molecule. As described later, it is preferable to use an isocyanate-based crosslinking agent as the crosslinking agent, and among the functional group-containing monomers, a hydroxyl-containing monomer having excellent reactivity with the isocyanate-based crosslinking agent is preferable.
Examples of the hydroxyl group-containing monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 3-hydroxybutyl (meth) acrylate, and 4-hydroxybutyl (meth) acrylate. These hydroxyl group-containing monomers may be used alone or in combination of two or more.
Examples of the carboxyl group-containing monomer include ethylenically unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid, and citraconic acid. These carboxyl group-containing monomers may be used alone or in combination of two or more.
Examples of the amino group-containing monomer or the substituted amino group-containing monomer include aminoethyl (meth) acrylate, n-butylaminoethyl (meth) acrylate, and the like. These amino group-containing monomers or substituted amino group-containing monomers may be used alone or in combination of two or more.
The (meth) acrylic acid ester constituting the acrylic polymer is preferably an alkyl (meth) acrylate having 1 to 20 carbon atoms in the alkyl group, more preferably an alkyl (meth) acrylate having 1 to 7 carbon atoms in the alkyl group, particularly preferably an alkyl (meth) acrylate having 1 to 6 carbon atoms in the alkyl group, further preferably an alkyl (meth) acrylate having 1 to 5 carbon atoms in the alkyl group, and most preferably an alkyl (meth) acrylate having 1 to 4 carbon atoms in the alkyl group. The alkyl (meth) acrylate may be used singly or in combination of two or more.
The (meth) acrylic acid alkyl ester having 1 to 4 carbon atoms, in which the most constituent unit is an alkyl group, is preferably contained in the acrylic polymer (main chain of the active energy ray-curable polymer). The number of squares measured by the above-described dicing method can be easily made to be 95 or more by increasing the adhesion between the obtained adhesive layer 12 and the substrate 11 by using the alkyl (meth) acrylate having 1 to 4 carbon atoms and having the largest number of structural units as alkyl groups.
Specific examples of the alkyl (meth) acrylate having 1 to 4 carbon atoms in the alkyl group include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, and butyl (meth) acrylate. Among them, methyl methacrylate and n-butyl acrylate are particularly preferably used in combination.
The acrylic polymer preferably contains 10 mass% or more, more preferably 15 mass% or more, particularly preferably 20 mass% or more, and still more preferably 25 mass% or more of the structural unit derived from the functional group-containing monomer. The acrylic polymer preferably contains 40 mass% or less, particularly preferably 35 mass% or less, and further preferably 30 mass% or less of the structural unit derived from the functional group-containing monomer.
The acrylic polymer preferably contains not less than 55% by mass, more preferably not less than 60% by mass, particularly preferably not less than 65% by mass, and still more preferably not less than 70% by mass of the structural unit derived from the (meth) acrylic ester or the derivative thereof. The acrylic polymer preferably contains not more than 90% by mass, more preferably not more than 85% by mass, particularly preferably not more than 80% by mass, and still more preferably not more than 75% by mass of the structural unit derived from the (meth) acrylate or the derivative thereof.
The acrylic copolymer is obtained by copolymerizing the functional group-containing monomer with a (meth) acrylate monomer or a derivative thereof by a conventional method, but other than these monomers, dimethylacrylamide, vinyl formate, vinyl acetate, styrene, and the like may be copolymerized.
The active energy ray-curable polymer can be obtained by reacting the acrylic polymer having the functional group-containing monomer unit described above with an unsaturated group-containing compound having a functional group bonded to the functional group.
The functional group of the unsaturated group-containing compound may be appropriately selected according to the type of the functional group-containing monomer unit of the acrylic polymer. For example, when the functional group of the acrylic polymer is a hydroxyl group, an amino group or a substituted amino group, the functional group of the unsaturated group-containing compound is preferably an isocyanate group or an epoxy group, and when the functional group of the acrylic polymer is an epoxy group, the functional group of the unsaturated group-containing compound is preferably an amino group, a carboxyl group or an aziridine group.
The unsaturated group-containing compound contains at least 1, preferably 1 to 6, more preferably 1 to 4 energy ray polymerizable carbon-carbon double bonds in 1 molecule. Specific examples of such an unsaturated group-containing compound include, for example, 2-methacryloxyethyl isocyanate, m-isopropenyl- α, α -dimethylbenzyl isocyanate, methacryloyl isocyanate, allyl isocyanate, and 1,1- (bisacryloxymethyl) ethyl isocyanate; an acryl monoisocyanate compound obtained by reacting a diisocyanate compound or a polyisocyanate compound with hydroxyethyl (meth) acrylate; an acryl monoisocyanate compound obtained by reacting a diisocyanate compound or a polyisocyanate compound with a polyol compound and hydroxyethyl (meth) acrylate; glycidyl (meth) acrylate; (meth) acrylic acid, 2- (1-aziridinyl) ethyl (meth) acrylate, 2-vinyl-2-oxazoline, 2-isopropenyl-2-oxazoline, and the like. These unsaturated group-containing compounds may be used singly or in combination of two or more. Among them, 2-methacryloyloxyethyl isocyanate is particularly preferable.
The unsaturated group-containing compound is preferably used in a proportion of 50 to 95 mol% relative to the number of moles of the functional group-containing monomer of the acrylic polymer, particularly preferably in a proportion of 60 to 93 mol% relative to the number of moles of the functional group-containing monomer of the acrylic polymer, and more preferably in a proportion of 70 to 90 mol% relative to the number of moles of the functional group-containing monomer of the acrylic polymer.
In the reaction of the acrylic polymer and the unsaturated group-containing compound, the temperature, pressure, solvent, time, presence or absence of a catalyst, and the kind of catalyst may be appropriately selected according to the combination of the functional group of the acrylic polymer and the functional group of the unsaturated group-containing compound. Thus, the functional group present in the acrylic polymer reacts with the functional group in the unsaturated group-containing compound, and the unsaturated group is introduced into the side chain in the acrylic polymer, whereby an active energy ray-curable polymer can be obtained.
The weight average molecular weight (Mw) of the active energy ray-curable polymer thus obtained is preferably 10 to 200 tens of thousands, more preferably 20 to 150 tens of thousands, particularly preferably 30 to 100 tens of thousands, further preferably 40 to 80 tens of thousands. The weight average molecular weight (Mw) in the present specification is a value in terms of standard polystyrene measured by Gel Permeation Chromatography (GPC).
(1-2) Cross-linking agent
As described above, the acrylic adhesive composition preferably contains a crosslinking agent. The crosslinking agent reacts with the functional group of the active energy ray-curable polymer to crosslink the active energy ray-curable polymer. Thus, the cohesive force of the adhesive can be improved, and the desired adhesive force can be obtained. Among the crosslinking agents, isocyanate-based crosslinking agents are preferable, toluene diisocyanate-based crosslinking agents or xylylene diisocyanate-based crosslinking agents are particularly preferable, and toluene diisocyanate-based crosslinking agents are further preferable. The toluene diisocyanate-based crosslinking agent is less likely to change the adhesion physical properties, and the adhesion between the obtained adhesive layer 12 and the substrate 11, particularly the substrate 11 containing the antistatic agent, is improved. As a result, the number of squares measured by the above-mentioned cross-hatch method can be easily made to be 95 or more.
The blending amount of the crosslinking agent (particularly, toluene isocyanate-based crosslinking agent) is preferably 3 parts by mass or more, more preferably more than 3 parts by mass, particularly preferably 4 parts by mass or more, further preferably 4.3 parts by mass or more, relative to 100 parts by mass of the acrylic polymer (active energy ray-curable polymer). The blending amount is preferably 10 parts by mass or less, particularly preferably 8 parts by mass or less, and further preferably 6.5 parts by mass or less. By making the blending amount of the crosslinking agent within the above range, the resulting adhesive layer 12 exhibits more excellent adhesion to the substrate 11.
(1-3) free epoxy resin
The free epoxy resin in the present embodiment is contained in the adhesive layer 12 in a state of substantially not reacting with the active energy ray-curable polymer. By including such a free epoxy resin in the adhesive layer 12, a film formed of the free epoxy resin can be formed on the interface of the work and the adhesive layer 12, and the interaction between the work and the adhesive layer 12 becomes relatively small. Therefore, even when the workpiece processing sheet 1 of the present embodiment is attached to a semiconductor wafer or the like immediately after back grinding, the adhesive force of the adhesive layer 12 is sufficiently reduced after irradiation with active energy rays, and the chip can be easily picked up.
The free epoxy resin in this embodiment includes compounds having at least one epoxy group in the molecule, and examples thereof include bisphenol a type, bisphenol F type, bisphenol S type, biphenyl type, phenol novolac type, cresol novolac type epoxy resins, and the like. It is preferable to introduce a soft skeleton via a low-polarity bonding group into these epoxy resins. The free epoxy resin may be used alone or in combination of two or more.
The free epoxy resin in this embodiment is preferably contained in the adhesive layer 12 in a state where epoxy groups remain. Further, the reactivity of the free epoxy resin and the active energy ray-curable polymer in the present embodiment is preferably inert, and therefore, a compound having no functional group such as an amino group or the like that activates an epoxy group is preferable.
The molecular weight of the free epoxy resin in this embodiment is preferably low. Specifically, it is preferably 300 to 2000, particularly preferably 350 to 1500, and further preferably 400 to 1000. By making the molecular weight of the free epoxy resin within the above range, a film formed of the free epoxy resin can be more easily formed on the interface of the work and the adhesive layer 12, so that the pick-up property of the chip becomes more excellent.
The content of the free epoxy resin in the acrylic pressure-sensitive adhesive composition of the present embodiment is preferably 5 parts by mass or more, more preferably 8 parts by mass or more, particularly preferably 10 parts by mass or more, and further preferably 12 parts by mass or more, relative to 100 parts by mass of the acrylic polymer. Thereby, the pick-up property by the free epoxy resin becomes more excellent. The content of the free epoxy resin is preferably less than 40 parts by mass, more preferably 35 parts by mass or less, particularly preferably 30 parts by mass or less, and further preferably 27 parts by mass or less, relative to 100 parts by mass of the acrylic polymer. This can suppress the decrease in adhesion between the adhesive layer 12 and the substrate 11, and can easily make the number of squares measured by the dicing method 95 or more.
(1-4) photopolymerization initiator
When ultraviolet rays are used as energy rays for curing an acrylic polymer (active energy ray-curable polymer), it is preferable to add a photopolymerization initiator, and by using the photopolymerization initiator, polymerization curing time and light irradiation amount can be reduced.
Specific examples of the photopolymerization initiator include benzophenone, acetophenone, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzoin benzoic acid, benzoin methyl benzoate, benzoin dimethyl ketal, 2, 4-diethylthioxanthone, 1-hydroxycyclohexylphenyl ketone, benzyldiphenyl sulfide, tetramethylthiuram monosulfide, azobisisobutyronitrile, benzil (benzozil), dibenzoyl, diacetyl, β -chloroanthraquinone, (2, 4, 6-trimethylbenzyl diphenyl) phosphine oxide, N-diethyldithiocarbamic acid 2-benzothiazole, oligo { 2-hydroxy-2-methyl-1- [4- (1-propenyl) phenyl ] propanone }, 2-dimethoxy-1, 2-diphenylethane-1-one, and the like. These photopolymerization initiators may be used alone or in combination of two or more.
The photopolymerization initiator is preferably used in an amount of 0.1 to 10 parts by mass, particularly preferably in an amount of 0.5 to 6 parts by mass, relative to 100 parts by mass of the acrylic polymer (active energy ray-curable polymer).
(1-5) other Components
In the acrylic pressure-sensitive adhesive composition of the present embodiment, other components may be added as appropriate in addition to the above components. Examples of the other component include a non-energy ray curable polymer component, an oligomer component, and a polymerizable branched polymer. In addition, the acrylic adhesive composition in the present embodiment preferably does not contain an epoxy curing agent.
(2) Thickness of adhesive layer
The thickness of the adhesive layer 12 in this embodiment is preferably 1 μm or more, more preferably 3 μm or more, particularly preferably 4 μm or more, and further preferably 5 μm or more. The thickness of the adhesive layer 12 is preferably 50 μm or less, more preferably 30 μm or less, particularly preferably 20 μm or less, and further preferably 10 μm or less. By setting the thickness of the adhesive layer 12 within the above-described range, the workpiece processing sheet 1 of the present embodiment exhibits a desired adhesiveness.
1-2. Substrate
As shown in fig. 1, the substrate 11 in this embodiment includes a surface layer 111 adjacent to the adhesive layer 12, a back surface layer 113 distant from the adhesive layer 12, and an intermediate layer 112 between the surface layer 111 and the back surface layer 113. However, the present invention is not limited to this, and may be a single-layer structure or a double-layer structure.
In the substrate 11 of the present embodiment, at least the surface layer 111 preferably contains an antistatic agent, and particularly, the surface layer 111 and the back surface layer 113 preferably contain an antistatic agent. Thus, the workpiece processing sheet 1 of the present embodiment has excellent antistatic properties. Therefore, peeling electrification when separating the peeling sheet and the workpiece from the workpiece processing sheet 1 can be favorably suppressed. Further, it is possible to satisfactorily prevent peeling electrification when separating the workpiece processing sheet 1 from the rotary table after cleaning and drying the workpiece on the workpiece processing sheet 1.
(1) Surface layer
For the workpiece processing sheet 1 of the present embodiment, it is preferable that the surface layer 111 contains an antistatic agent. Thus, excellent antistatic properties can be obtained. In addition, although the antistatic agent may cause cutting blades to be generated at the time of cutting, the generation of cutting blades may be significantly reduced as compared with the case where the antistatic agent is contained in the base material 11 as a whole, by reducing the thickness of the surface layer 111 and making the intermediate layer 112 free of the antistatic agent or reducing the content of the antistatic agent in the intermediate layer 112.
The antistatic agent in the present embodiment is not particularly limited, and a known antistatic agent may be used. Examples of the antistatic agent include a low molecular type antistatic agent and a high molecular type antistatic agent, but the high molecular type antistatic agent is preferable in that the antistatic agent is less likely to bleed out (bleedout) from the formed layer. In addition, if the surface layer 111 contains a polymer type antistatic agent, the pickup becomes more excellent. Although the reason for this is not specified, it is considered that the polymer type antistatic agent exerts an effect as an additive of some kind.
The polymer type antistatic agent may be a copolymer having polyether units such as polyether ester amide and polyether polyolefin block copolymer, and these copolymers may contain a metal salt such as alkali metal salt and alkaline earth metal salt or an ionic liquid.
The content of the antistatic agent in the surface layer 111 is preferably 3 mass% or more, particularly preferably 5 mass% or more, and further preferably 10 mass% or more. Thus, the antistatic performance becomes more excellent. The content is preferably 40% by mass or less, particularly preferably 35% by mass or less, and further preferably 30% by mass or less. Thereby, the mechanical physical properties of the base material 11 can be well maintained.
The material constituting the surface layer 111 other than the antistatic agent preferably contains at least one of an olefin-based thermoplastic elastomer (hereinafter sometimes referred to as "olefin-based elastomer") and a polyolefin-based resin, and particularly preferably contains at least an olefin-based elastomer and, if necessary, a polyolefin-based resin. By these components, the pick-up property becomes more excellent. The "olefin elastomer" is a copolymer containing a structural unit derived from an olefin or a derivative thereof (olefin compound), and is a material having rubber-like elasticity in a temperature range including normal temperature and thermoplastic properties.
As examples of the olefin-based elastomer, olefin-based elastomers containing at least one resin selected from the group consisting of ethylene-propylene copolymers, ethylene- α -olefin copolymers, propylene- α -olefin copolymers, butene- α -olefin copolymers, ethylene-propylene- α -olefin copolymers, ethylene-butene- α -olefin copolymers, propylene-butene- α -olefin copolymers, and ethylene-propylene-butene- α -olefin copolymers can be cited. Among them, ethylene-propylene copolymers are preferable.
The content of the olefin elastomer in the surface layer 111 is preferably 30% by mass or more, particularly preferably 35% by mass or more, and further preferably 40% by mass or more. The content is preferably 80% by mass or less, particularly preferably 75% by mass or less, and further preferably 70% by mass or less. By setting the content of the olefin elastomer in the surface layer 111 within the above range, the flexibility of the base material 11 is improved, and the pickup is further improved.
By containing the polyolefin resin in the surface layer 111, the film forming property and the edge chipping (chipping) suppression at the time of film formation are excellent. In the present specification, the polyolefin-based resin means a homopolymer or a copolymer having an olefin as a monomer or a copolymer having an olefin and a molecule other than an olefin as a monomer, and the mass ratio of the portion based on the olefin unit in the resin after polymerization is 1.0% by mass or more.
The polyolefin-based resin is not particularly limited as long as the desired effect can be obtained. The polymer constituting the polyolefin-based resin may be linear or may have a side chain. Further, the aromatic ring and the aliphatic ring may be present.
Examples of the olefin monomer constituting the polyolefin resin include olefin monomers having 2 to 8 carbon atoms, alpha-olefin monomers having 3 to 18 carbon atoms, olefin monomers having a cyclic structure, and the like. Examples of the olefin monomer having 2 to 8 carbon atoms include ethylene, propylene, 2-butene, octene, and the like. Examples of the α -olefin monomer having 3 to 18 carbon atoms include propylene, 1-butene, 4-methyl-1-pentene, 1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, and 1-octadecene. Examples of the olefin monomer having a cyclic structure include norbornene, cyclopentadiene, cyclohexadiene, dicyclopentadiene, tetracyclododecene, derivatives thereof, and the like.
The polyolefin-based resin may be used singly or in combination of two or more.
In the above specific examples of the polyolefin-based resin, at least one of polyethylene containing ethylene as a main polymerization unit and polypropylene containing propylene as a main polymerization unit is preferably used.
The polypropylene is usually a homo-polypropylene, a random polypropylene or a block polypropylene. These polypropylenes may be used singly or in combination of two or more. In this embodiment, random polypropylene is preferably used from the viewpoint of expandability.
When the polyolefin-based resin contains polyethylene, the polyethylene may be any one of high-density polyethylene, medium-density polyethylene, low-density polyethylene, ultra-low-density polyethylene and linear low-density polyethylene, or may be a mixture of two or more thereof.
The content of the polyolefin resin in the surface layer 111 is preferably 10 mass% or more, particularly preferably 15 mass% or more, and further preferably 20 mass% or more, from the viewpoints of film formability and edge chipping suppression. From the viewpoint of the picking up property due to flexibility, the content is preferably 45 mass% or less, particularly preferably 40 mass% or less, and further preferably 35 mass% or less.
The surface layer 111 may contain other components than the above components, for example, components in a general base material for a workpiece processing sheet. Examples of such components include various additives such as flame retardants, plasticizers, lubricants, antioxidants, colorants, infrared absorbers, ultraviolet absorbers, and ion capturing agents. The content of these additives is not particularly limited, but is preferably within a range where the surface layer 111 performs a desired function.
(2) Intermediate layer
In the present embodiment, the material constituting the intermediate layer 112 is not particularly limited, and preferably contains at least one of an olefin-based elastomer and a polyolefin-based resin, more preferably contains at least an olefin-based elastomer and further contains a polyolefin-based resin as required, and particularly preferably contains at least an olefin-based elastomer and further contains a polyolefin-based resin and a styrene-based elastomer as required. By these components, the flexibility of the base material 11 becomes good, and the pick-up property becomes more excellent. In particular, when the intermediate layer 112 contains a styrene-based elastomer, the picking up property due to flexibility becomes more excellent.
The olefin elastomer, the polyolefin resin and the styrene elastomer are preferably the same as those exemplified in the surface layer 111.
The content of the olefin elastomer in the intermediate layer 112 is preferably 10% by mass or more, particularly preferably 15% by mass or more, and further preferably 20% by mass or more. The content is preferably 50% by mass or less, particularly preferably 45% by mass or less, and further preferably 40% by mass or less. By making the content of the olefin-based elastomer in the intermediate layer 112 within the above range, the pickup property based on flexibility becomes more excellent.
The content of the polyolefin-based resin in the intermediate layer 112 is preferably 10% by mass or more, particularly preferably 15% by mass or more, and further preferably 20% by mass or more. The content is preferably 45% by mass or less, particularly preferably 40% by mass or less, and further preferably 35% by mass or less. By making the content of the polyolefin-based resin in the intermediate layer 112 within the above range, the pickup property based on flexibility becomes more excellent.
The content of the styrene-based elastomer in the intermediate layer 112 is preferably 10% by mass or more, particularly preferably 15% by mass or more, and further preferably 20% by mass or more. The content is preferably 45% by mass or less, particularly preferably 40% by mass or less, and further preferably 35% by mass or less. By making the content of the styrene-based resin in the intermediate layer 112 within the above range, the picking up property based on flexibility becomes more excellent.
Here, although the intermediate layer 112 may contain an antistatic agent, it is preferable that the intermediate layer 112 does not contain an antistatic agent in view of easily suppressing the generation of cutting chips. When the intermediate layer 112 contains an antistatic agent, the intermediate layer 112 preferably contains an antistatic agent smaller than the content (unit: mass%) of the antistatic agent in the surface layer 111 and the back surface layer 113. Specifically, in the intermediate layer 112, the content thereof is preferably less than 5 mass%, more preferably less than 3 mass%, particularly preferably less than 1 mass%, and most preferably 0 mass%. When the intermediate layer 112 contains an antistatic agent, the lower limit of the content thereof is, for example, 0.01 mass% or more. As described above, by having the intermediate layer 112 containing no antistatic agent or a small amount thereof exist below the surface layer 111 (preferably a thin layer), the generation of cutting chips is significantly reduced as compared with the case where the antistatic agent is contained in the entire substrate.
The intermediate layer 112 may contain other components than the above components, for example, components in a general base material for a sheet for workpiece processing, in the same manner as the surface layer 111.
(3) Back surface layer
In this embodiment, the back surface layer 113 preferably contains an antistatic agent. Thus, more excellent antistatic performance can be obtained. On the other hand, as described above, the antistatic agent causes cutting blades to be generated at the time of cutting, but generally the cutting blade does not reach the back surface layer 113, and therefore, even if the back surface layer 113 contains the antistatic agent, cutting blades are not caused to be generated.
As the antistatic agent in the back surface layer 113, the same antistatic agent as that in the surface layer 111 may be used.
The content of the antistatic agent in the back surface layer 113 is preferably 10 mass% or more, particularly preferably 20 mass% or more, and further preferably 30 mass% or more. Thus, good antistatic performance is easily exhibited. The content is preferably 50% by mass or less, particularly preferably 45% by mass or less, and further preferably 40% by mass or less. Thereby, the mechanical physical properties of the base material 11 can be well maintained.
The material constituting the back surface layer 113 other than the antistatic agent is not particularly limited as long as the mechanical physical properties of the base material 11 can be well maintained, but preferably contains at least one of an olefin elastomer and a polyolefin resin, and particularly preferably contains at least an olefin elastomer. Thus, the substrate 11 is excellent in flexibility and in pick-up property.
The preferred olefin-based elastomer is the same as exemplified in the surface layer 111.
The content of the olefin elastomer in the back layer 113 is preferably 30% by mass or more, particularly preferably 35% by mass or more, and further preferably 40% by mass or more. The content is preferably 85% by mass or less, particularly preferably 80% by mass or less, and further preferably 75% by mass or less. By making the content of the olefin elastomer in the back surface layer 113 within the above range, the pickup property based on flexibility becomes excellent.
In addition, the back layer 113 preferably does not contain a styrene-based elastomer as the thermoplastic elastomer. If the styrene-based elastomer is contained, blocking may occur during film formation or pickup may be affected. Even if the back surface layer 113 contains a styrene-based elastomer, the content thereof is preferably 2 mass% or less, and particularly preferably 1 mass% or less.
The back surface layer 113 may contain other components than the above components, for example, components used in a general base material of a sheet for workpiece processing, similarly to the surface layer 111 and the intermediate layer 112.
(4) Surface treatment of substrates
In order to improve the adhesion to the adhesive layer 12, the surface of the substrate 11 on which the adhesive layer 12 is laminated may be subjected to surface treatments such as a primer treatment, a corona treatment, a plasma treatment, and a roughening treatment (sanding treatment). Examples of the roughening treatment include an embossing method and a sand blasting method. Among them, corona treatment is preferably performed.
(5) Method for producing base material
The method for producing the base material 11 of the present embodiment is not particularly limited, and for example, a melt extrusion method such as a T-die method or a circular die method (pellet method) can be used; a calendaring method; dry, wet, and other solution methods. Among them, the melt extrusion method is preferable, and the T-die method is particularly preferable from the viewpoint of efficient production of the base material.
In the case of producing the base material 11 by melt extrusion, the components constituting each layer are kneaded, and the thus obtained kneaded material is directly or first produced into pellets, and then a plurality of layers are simultaneously extruded (co-extruded) by using a known extruder to produce a film.
(6) Thickness of (L)
The thickness of the surface layer 111 in this embodiment is preferably 10 μm or less, particularly preferably 8 μm or less, and further preferably 4 μm or less. Thus, the thickness of the surface layer 111 near the adhesive layer 12 is made thin, and the generation of cutting chips can be well suppressed while the required antistatic property is exhibited.
The thickness of the surface layer 111 is preferably 0.5 μm or more, particularly preferably 1 μm or more, and further preferably 2 μm or more. Thus, the antistatic property is easily exhibited and the pickup property is more excellent.
The thickness of the intermediate layer 112 in this embodiment is preferably 40 μm or more, particularly preferably 50 μm or more, and further preferably 60 μm or more. Thus, the workpiece processing sheet 1 is made to have appropriate strength easily, and the workpiece fixed to the workpiece processing sheet 1 is easily supported well. The thickness of the intermediate layer 112 is preferably 100 μm or less, particularly preferably 90 μm or less, and further preferably 80 μm or less.
The thickness of the back layer 113 in this embodiment is preferably 2 μm or more, particularly preferably 4 μm or more, and further preferably 8 μm or more. When the back surface layer 113 contains an antistatic agent, the antistatic property of the workpiece processing sheet 1 becomes more excellent by the thickness described above. The thickness of the back surface layer 113 is preferably 40 μm or less, particularly preferably 30 μm or less, and further preferably 25 μm
The following is given.
The thickness of the entire substrate 11 in this embodiment is preferably 50 μm or more, particularly preferably 60 μm or more, and further preferably 70 μm or more. The thickness is preferably 140 μm or less, particularly preferably 120 μm or less, and further preferably 100 μm or less. By setting the thickness of the entire base material 11 within the above range, it is easy to satisfactorily support the workpiece fixed to the workpiece processing sheet 1.
1-3 stripping sheet
In the work processing sheet 1 of the present embodiment, for the purpose of protecting the surface of the adhesive layer 12 opposite to the base material 11 (hereinafter, sometimes referred to as "adhesive surface"), a release sheet may be laminated on the surface before the surface is attached to the work.
The release sheet may be any one, and examples thereof include a release sheet in which a plastic film is subjected to a release treatment with a release agent or the like. Specific examples of the plastic film include polyester films such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; polyolefin films such as polypropylene and polyethylene. As the release agent, silicones, fluorides, long-chain alkyl groups, and the like can be used, and among them, silicones which are inexpensive and can obtain stable performance are preferable.
The thickness of the release sheet is not particularly limited, and may be, for example, 16 μm or more and 250 μm
The following is given.
1-4. Other
In the work processing sheet 1 of the present embodiment, an adhesive layer may be laminated on a surface of the adhesive layer 12 opposite to the base material 11. At this time, the workpiece processing sheet 1 of the present embodiment can be used as a die-bonding (die-bonding) sheet. By attaching a work to a surface of the adhesive layer of the sheet opposite to the adhesive layer 12 and cutting the adhesive layer together with the work, a chip having the adhesive layer laminated with the singulation can be obtained. The chip can be easily fixed to an object on which the chip is mounted by using the singulated adhesive layer. As a material constituting the pressure-sensitive adhesive layer, a material containing a thermoplastic resin and a thermosetting pressure-sensitive adhesive component having a low molecular weight, a material containing a thermosetting pressure-sensitive adhesive component in a B-stage (semi-cured state), or the like is preferably used.
In the work processing sheet 1 of the present embodiment, a protective film forming layer may be laminated on the adhesive surface of the adhesive layer 12. In this case, the workpiece processing sheet 1 of the present embodiment can be used as a protective film forming and cutting sheet. By attaching a work to a surface of the protective film forming layer on the opposite side of the adhesive layer 12 in such a sheet and cutting the protective film forming layer together with the work, a chip in which the protective film forming layers are laminated singly can be obtained. As the work, a work having a circuit formed on one surface is preferably used, and in this case, a protective film formation layer is generally laminated on a surface opposite to the surface on which the circuit is formed. By curing the singulated protective film formation layer at a prescribed time point, a protective film having sufficient durability can be formed on the chip. The protective film forming layer is preferably formed of an uncured curable adhesive.
2. Physical properties of sheet for workpiece processing
In the work processing sheet 1 of the present embodiment, the surface resistivity of the surface (adhesive surface) of the adhesive layer 12 opposite to the base material 11 after the active energy ray curing is preferably 1.0x10 13 Ω/
And ∈10, particularly preferably 1.0X10 12 Ω/≡or less. Thus, the workpiece processing sheet 1 of the present embodiment can be made to have excellent antistatic properties. The lower limit of the surface resistivity is not particularly limited, but is preferably 1.0X10, for example 8 Omega/≡or more, particularly preferably 1.0X10) 9 Ω/≡or more. The details of the method for measuring the surface resistivity in the present specification are described in the test examples described below.
3. Method for manufacturing sheet for processing workpiece
As a method for manufacturing the workpiece processing sheet 1 of the present embodiment, for example, preferable is: after the adhesive layer 12 is formed on the release sheet, the surface of the surface layer 111 side of the base material 11 is laminated on the surface of the adhesive layer 12 opposite to the release sheet, thereby obtaining the work processing sheet 1.
For the formation of the adhesive layer 12, for example, a coating liquid containing an adhesive composition for forming the adhesive layer 12 and a solvent or a dispersion medium as needed is prepared. The coating liquid is then applied to a releasable surface (hereinafter, sometimes referred to as "release surface") of the release sheet. Next, by drying the obtained coating film, the adhesive layer 12 can be formed.
The coating liquid can be applied by a known method, and for example, bar coating, blade coating (knife coating method), roll coating, blade coating (blade coating method), die coating (die coating method), gravure coating, and the like can be used. The properties of the coating liquid are not particularly limited as long as the coating liquid can be applied, and there are cases where the component for forming the adhesive layer 12 is contained as a solute, and there are cases where the component for forming the adhesive layer 12 is contained as a dispersion. The release sheet may be peeled off as a process material, or the adhesive layer 12 may be protected until it is attached to an adherend.
When the acrylic adhesive composition for forming the adhesive layer 12 contains the crosslinking agent, it is preferable to form a crosslinked structure in the adhesive layer 12 at a desired existing density by crosslinking the polymer component in the coating film with the crosslinking agent by changing the drying conditions (temperature, time, etc.) or by separately providing a heat treatment. Further, after the adhesive layer 12 and the base material 11 are bonded, curing may be performed by standing for several days at 23℃and a relative humidity of 50%, for example, so that the crosslinking reaction is sufficiently performed.
4. Method for using workpiece processing sheet
The workpiece processing sheet 1 of the present embodiment can be used for processing a workpiece such as a semiconductor wafer. That is, the adhesive surface of the workpiece processing sheet 1 of the present embodiment can be attached to a workpiece, and then the workpiece processing can be performed on the workpiece processing sheet 1. According to this processing, the workpiece processing sheet 1 of the present embodiment can be used as a back surface grinding sheet, a dicing sheet, an expanding sheet, a pickup sheet, or the like. Here, examples of the work include semiconductor members such as a semiconductor wafer and a semiconductor package; glass members such as glass plates.
As described above, since the workpiece processing sheet 1 of the present embodiment is excellent in the pickup property, it is preferably a sheet used in a process including at least a pickup process. For example, the dicing sheet may be used in the process from dicing to picking up, or the transfer sheet may be used for transferring a chip obtained by dicing and picking up.
Preferably: before the above-described pickup, that is, before the processing of the workpiece is completed on the workpiece processing sheet 1 and the processed workpiece (chip) is separated (picked up) from the workpiece processing sheet 1, the adhesive layer 12 in the workpiece processing sheet 1 of the present embodiment is irradiated with active energy rays, thereby curing the adhesive layer 12 and further reducing the adhesive force.
As the active energy ray, for example, an electromagnetic wave or a ray having energy quanta in a charged particle beam may be used, and specifically, ultraviolet rays, electron beams, or the like may be used. Particularly preferred is ultraviolet radiation which is easy to handle. The irradiation of ultraviolet rays may be performed using a high-pressure mercury lamp, a xenon lamp, an LED, or the like, and the irradiation amount of ultraviolet rays is preferably 50mW/cm 2 Above and 1000mW/cm 2 The following is given. Further, the light quantity is preferably 50mJ/cm 2 The above is particularly preferably 80mJ/cm 2 The above is more preferably 150mJ/cm 2 The above. Further, the light quantity is preferably 10000mJ/cm 2 Hereinafter, it is particularly preferably 5000mJ/cm 2 Hereinafter, it is more preferably 2000mJ/cm 2 The following is given. On the other hand, the electron beam irradiation may be performed by an electron beam accelerator or the like, and the irradiation amount of the electron beam is preferably 10krad or more and 1000krad or less.
As described above, by appropriately selecting the materials and thicknesses of the surface layer 111 and the intermediate layer 112, the workpiece processing sheet 1 of the present embodiment can favorably suppress the generation of cutting sheets at the time of cutting. In this case, the workpiece processing sheet 1 of the present embodiment is particularly suitable for use as a cutting sheet in the workpiece processing sheet described above.
Further, as described above, the workpiece processing sheet 1 of the present embodiment has excellent antistatic properties. The workpiece processing sheet 1 of the present embodiment can suppress peeling electrification at the time of separating the peeling sheet or at the time of separating the workpiece. Further, the workpiece processing sheet 1 of the present embodiment can also effectively suppress peeling electrification when the workpiece processing sheet is separated from the rotary table after cleaning and drying of the chips in a state where the workpiece processing sheet is fixed to the rotary table. Therefore, the workpiece processing sheet 1 of the present embodiment can be suitably used for the above-described cleaning and drying.
The workpiece processing sheet 1 of the present embodiment is particularly suitable for application in which the workpiece processing sheet is attached to a semiconductor wafer immediately after back grinding, and then cut and then picked up. Even in such applications, the pick-up of the chip can be easily performed.
In addition, when the work piece processing sheet 1 of the present embodiment is provided with the above-described adhesive layer, the work piece processing sheet 1 can be used as a dicing die-bonding sheet. Further, when the workpiece processing sheet 1 of the present embodiment is provided with the protective film forming layer, the workpiece processing sheet 1 can be used as a protective film forming and cutting sheet.
The embodiments described above are described for easy understanding of the present invention, and are not described for limiting the present invention. Accordingly, each element disclosed in the above embodiments also covers all design changes and equivalents which fall within the technical scope of the present invention.
For example, another layer may be laminated between the base material 11 and the adhesive layer 12 of the workpiece processing sheet 1 of the present embodiment or on the surface of the base material 11 opposite to the adhesive layer 12. Further, other layers may be laminated on the surface of the surface layer 111 opposite to the intermediate layer 112, between the surface layer 111 and the intermediate layer 112, between the intermediate layer 112 and the back surface layer 113, and on the surface of the back surface layer 113 opposite to the intermediate layer 112, respectively.
Examples
The present invention will be described in more detail with reference to examples, but the scope of the present invention is not limited to these examples.
Example 1
(1) Manufacture of a substrate
30 parts by mass of a random polypropylene resin (manufactured by Japan Polypropylene Corporation under the product name "NOVATEC FX 3B"), 45 parts by mass of an olefin elastomer (manufactured by Japan Polypropylene Corporation under the product name "wernex RFX 4V"), and 25 parts by mass of a polymer antistatic agent (manufactured by SANYO CHEMICAL INDUSTRIES, LTD. under the product name "PELECTRON PVL") were dried, and then kneaded by a biaxial kneader, whereby particles for a surface layer were obtained.
Further, 28 parts by mass of a random polypropylene resin (manufactured by Japan Polypropylene Corporation under the product name "NOVATEC FX 3B"), 39 parts by mass of an olefin-based elastomer (manufactured by Japan Polypropylene Corporation under the product name "werndex RFX 4V"), and 33 parts by mass of a styrene-ethylene-butylene-styrene copolymer (SEBS) as a styrene-based elastomer (manufactured by Asahi Kasei Corporation under the product name "Tuftec H1041", styrene ratio: 30 mass%) were dried, and then kneaded by a biaxial kneader, whereby pellets for an intermediate layer were obtained.
Further, 70 parts by mass of an olefin elastomer (manufactured by Japan Polypropylene Corporation under the product name "WELNEX RFX 4V") and 30 parts by mass of a polymer type antistatic agent (manufactured by SANYO CHEMICAL INDUSTRIES, LTD. under the product name "PELECTRON PVL") were dried, and kneaded by a biaxial kneader, whereby particles for a back surface layer were obtained.
Using the 3 kinds of pellets obtained above, coextrusion molding was performed by a small-sized T-die extruder (Toyo Seiki Seisaku-sho, ltd., manufactured under the product name "LABO PLASTOMIL"), to obtain a three-layer-structured substrate having a thickness of 80 μm in which a surface layer having a thickness of 2 μm, an intermediate layer having a thickness of 64 μm, and a back layer having a thickness of 14 μm were laminated in this order.
(2) Preparation of acrylic adhesive composition
By a solution polymerization method, 60 parts by mass of n-Butyl Acrylate (BA), 10 parts by mass of Methyl Methacrylate (MMA), and 30 parts by mass of 2-hydroxyethyl acrylate (HEA) were polymerized to obtain a (meth) acrylate polymer. Next, 2-methacryloyloxyethyl isocyanate (MOI) was added in an amount corresponding to 90 mol% relative to 2-hydroxyethyl acrylate constituting the above (meth) acrylate polymer, and dibutyltin dilaurate (DBTDL) as a tin-containing catalyst was added in an amount of 0.13 parts by mass relative to 100 parts by mass of the above (meth) acrylate polymer. Then, the reaction was carried out at 50℃for 48 hours, whereby a (meth) acrylate polymer having an active energy ray-curable group introduced into the side chain was obtained. The weight average molecular weight of the active energy ray-curable polymer was measured by the following method, and found to be 50 ten thousand.
100 parts by mass (solid content equivalent, the same applies hereinafter) of the (meth) acrylate polymer having an active energy ray-curable group introduced into the side chain obtained above (active energy ray-curable polymer), 4.5 parts by mass of trimethylolpropane-modified toluene diisocyanate (manufactured by TOSOH CORPORATION, product name "CORONATE L") as a crosslinking agent, 20 parts by mass of bisphenol a-type epoxy resin (2 epoxy groups at the end and a flexible skeleton introduced via a low-polarity bonding group) as a free epoxy resin (manufactured by DIC CORPORATION, product name "epicolin EXA-4850-150", molecular weight: 900) and 3 parts by mass of 2-hydroxy-1- {4- [4- (2-hydroxy-2-methyl-propionyl) benzyl ] phenyl } -2-methylpropan-1-one (manufactured by IGM RESINS, product name "omni 127") as a photopolymerization initiator were mixed in a solvent to obtain a coating liquid of an acrylic adhesive composition.
(3) Formation of adhesive layer
The coating liquid of the acrylic adhesive composition obtained in the step (2) was applied to the release surface of a release sheet (manufactured by LINTEC Corporation, product name "SP-PET 381031") having a silicone-based release agent layer formed on one surface of a polyethylene terephthalate film having a thickness of 38 μm, and dried by heating, whereby a laminate having an adhesive layer having a thickness of 5 μm formed on the release sheet was obtained.
(4) Production of adhesive sheet
The surface of the substrate on the surface layer side obtained in the step (1) is subjected to corona treatment, and the surface on the surface layer side is bonded to the surface on the adhesive layer side of the laminate obtained in the step (3), whereby a sheet for workpiece processing is obtained. Then, the cells were stored at 23℃under 50% RH for 2 weeks.
Here, the weight average molecular weight (Mw) is a weight average molecular weight in terms of standard polystyrene measured using Gel Permeation Chromatography (GPC) under the following conditions (GPC measurement).
< measurement conditions >
Measurement device: TOSOH CORPORATION, HLC-8320
GPC column (passing in the following order): TOSOH CORPORATION TSK gel SuperH-H
TSK gel superHM-H
TSK gel superH2000
Measuring solvent: tetrahydrofuran (THF)
Measurement temperature: 40 DEG C
Examples 2 to 4 and comparative examples 1 to 4
A piece for processing a workpiece was produced in the same manner as in example 1, except that the composition of the acrylic adhesive composition was changed as shown in table 1.
Here, as the active energy ray-curable polymer in example 4, a polymer prepared in the following manner was used. By a solution polymerization method, 50 parts by mass of n-Butyl Acrylate (BA), 20 parts by mass of Methyl Methacrylate (MMA), and 30 parts by mass of 2-hydroxyethyl acrylate (HEA) were polymerized, thereby obtaining a (meth) acrylate polymer. Next, 2-methacryloyloxyethyl isocyanate (MOI) was added in an amount corresponding to 90 mol% relative to 2-hydroxyethyl acrylate constituting the above (meth) acrylate polymer, and dibutyltin dilaurate (DBTDL) as a tin-containing catalyst was added in an amount of 0.13 parts by mass relative to 100 parts by mass of the above (meth) acrylate polymer. Then, the reaction was carried out at 50℃for 48 hours, whereby a (meth) acrylate polymer having an active energy ray-curable group introduced into the side chain was obtained. The weight average molecular weight of the active energy ray-curable polymer was measured by the above method and found to be 50 ten thousand.
Further, as the active energy ray-curable polymer in comparative example 2, a polymer prepared in the following manner was used. 45 parts by mass of 2-ethylhexyl acrylate (2 EHA), 35 parts by mass of vinyl acetate (VAc) and 20 parts by mass of 2-hydroxyethyl acrylate (HEA) were polymerized by a solution polymerization method, thereby obtaining a (meth) acrylate polymer. Next, 2-methacryloyloxyethyl isocyanate (MOI) was added in an amount corresponding to 80 mol% relative to 2-hydroxyethyl acrylate constituting the above (meth) acrylate polymer, and dibutyltin dilaurate (DBTDL) as a tin-containing catalyst was added in an amount of 0.13 parts by mass relative to 100 parts by mass of the above (meth) acrylate polymer. Then, the reaction was carried out at 50℃for 48 hours, whereby a (meth) acrylate polymer having an active energy ray-curable group introduced into the side chain was obtained. The weight average molecular weight of the active energy ray-curable polymer was measured by the above method and found to be 50 ten thousand.
Example 5
24 parts by mass of a random polypropylene resin (manufactured by Japan Polypropylene Corporation, product name "NOVATEC FX 3B"), 33 parts by mass of an olefin-based elastomer (manufactured by Japan Polypropylene Corporation, product name "welantex RFX 4V"), 28 parts by mass of a styrene-ethylene-butylene-styrene copolymer (SEBS) as a styrene-based elastomer (manufactured by Asahi Kasei Corporation, product name "Tuftec H1041", styrene ratio: 30% by mass), and 15 parts by mass of a polymer-based antistatic agent (manufactured by SANYO CHEMICAL INDUSTRIES, LTD., product name "PELECTRON PVL") were dried, and then kneaded by a biaxial kneader, whereby pellets for an intermediate layer were obtained.
A substrate was produced in the same manner as in example 1, except that the above-described particles were used as the particles for an intermediate layer. Then, using this base material, a piece for workpiece processing was produced in the same manner as in example 1.
Comparative example 5
Using the same apparatus as in example 1, a film (thickness: 80 μm) formed of a single layer of an ethylene-methacrylic acid copolymer (Dow-Mitsui Polychemicals co., ltd. Manufactured under the product name "NUCREL N0903 HC") was produced. The surface of the adhesive layer-laminated side of the obtained film was irradiated with an electron beam of 10kGy twice for 2.2 seconds each time, and was used as a base material. A piece for processing a workpiece was produced in the same manner as in example 1, except that the base material was used and the composition of the acrylic adhesive composition was changed as shown in table 1. The same active energy ray-curable polymer as comparative example 2 was used.
Test example 1 (evaluation of adhesion of substrate/adhesive layer)
The workpiece processing sheets manufactured in examples and comparative examples were placed on the mirror surface of the mirror wafer so that the release sheet side was in contact with the mirror surface.Ultraviolet (UV) irradiation (manufactured by LINTEC Corporation, product name "RAD-2000") was performed on the adhesive layer of the work piece processing sheet via a base material by using an ultraviolet irradiation device (illuminance: 230 mW/cm) 2 Light amount: 190mJ/cm 2 ) The adhesive layer is cured.
Next, a dicing was performed by a dicing blade from the side of the surface (exposed surface) of the adhesive layer (cured) of the workpiece processing sheet opposite to the base material, and a dicing portion having a number of squares of 100 was formed so that the dicing pitch was 5mm and the dicing line was 11×11 pieces, based on the dicing method of JIS K5600-5-6:1999. Then, an adhesive Tape made of cellose Tape (registered trademark) manufactured by nichiba co., ltd. Was attached to the dicing portion, and the adhesive Tape attached to the dicing portion was peeled off. The number of squares remaining after the release of the adhesive tape was taken as x, and the remaining ratio was represented by x/100. When the value of x/100 is 95/100 or more, it can be determined that the adhesion between the substrate and the adhesive layer is excellent. The results are shown in Table 2.
Test example 2 (evaluation of pickup Property)
A freshly polished silicon wafer polished to 150 μm at #2000 was prepared by a polishing machine (manufactured by DISCO Corporation, product name "DFG 8540").
The release sheet was peeled off from the work processing sheet produced in examples and comparative examples, and then the exposed surface of the exposed adhesive layer was attached to the polished surface of the silicon wafer using a laminator (product name "Adwill RAD2500m/12", produced by LINTEC Corporation). The work piece processing sheet was attached to the silicon wafer within 15 minutes after the completion of polishing the silicon wafer. Next, a dicing ring frame is attached to a peripheral portion of the exposed surface of the workpiece processing sheet (a position not overlapping the silicon wafer). Further, the piece for workpiece processing is cut according to the outer diameter of the ring frame.
Then, using a cutting device (DISCO Corporation, manufactured, product name
"DFD-6362"), dicing was performed under the following dicing conditions, whereby the silicon wafer was singulated into chips having a size of 10mm×10 mm.
< cleavage conditions >
Wafer thickness: 150 μm
A blade: DISCO Corporation, product name "ZH05-SD2000-N1-90CC"
Blade rotation speed: 35000rpm
Cutting speed: 60 mm/sec
Depth of feed: 0.060mm
Cutting water amount: 1.0L/min
Cutting water temperature: 20 DEG C
After the work piece processing sheet was attached to the polished surface of the silicon wafer for 48 hours, the adhesive layer of the work piece processing sheet was irradiated with Ultraviolet (UV) (illuminance: 230 mW/cm) through a base material using an ultraviolet irradiation device (manufactured by LINTEC Corporation, product name "RAD-2000 m/12") 2 Light amount: 190mJ/cm 2 ) The adhesive layer is cured.
Next, a chip was picked up from the workpiece processing sheet using a pick-up device (manufactured by Canon Machinery inc, product name "bump D510") under the following pick-up conditions.
< pickup Condition >
Pick-up mode: 4 ejector pin
Ejector pin push speed: 5mm/s
Top pin push amount: 100-800 mu m
The amount of lift-off required to pick up the chip is shown in table 2. When the push-up amount is 400 μm or less, it can be determined that the pick-up property is excellent.
Test example 3 (evaluation of cutting blade inhibition effect)
After the release sheet was peeled off from the work processing sheets produced in examples and comparative examples, the exposed surface of the exposed adhesive layer was attached to one surface of an 8-inch silicon wafer using a tape mounter (product name "Adwill RAD2500m/12", manufactured by LINTEC Corporation). Next, a dicing ring frame is attached to a peripheral portion of the exposed surface of the workpiece processing sheet (a position not overlapping the silicon wafer). Further, the piece for workpiece processing is cut according to the outer diameter of the ring frame.
Thereafter, dicing was performed using a dicing apparatus (manufactured by DISCO Corporation, product name "DFD 6362") under the following dicing conditions, whereby the silicon wafer was singulated into chips having a size of 0.8mm×20 mm.
< cleavage conditions >
Wafer thickness: 100 μm
A blade: each of the following Z1 and Z2 is manufactured by DISCO Corporation
Z1: product name "ZH05-SD3500-N1-50 DF01"
Z2: product name "ZH05-SD3000-N1-50 ED"
Blade rotation speed
Z1：50000rpm
Z2：35000rpm
Cutting speed: 100 mm/sec
Depth of feed
Z1：0.135mm
Z2：0.055mm
Cutting water amount: 1.0L/min
Cutting water temperature: 20 DEG C
After dicing, the surfaces of the 1000 chips obtained were observed by using an appearance inspection device (product name "Eagle" manufactured by Camtek corporation), and the number of chips was measured. Then, the number of cutting pieces per chip (=frequency of cutting piece generation) is calculated.
Then, the cutting blade suppression effect (cutting resistance) was evaluated according to the following criteria. The evaluation results are shown in table 2.
And (2) the following steps: the cutting blade generation frequency is less than 0.002.
X: the cutting blade generation frequency is 0.002 or more.
[ test example 4] (measurement of surface resistivity)
The workpiece processing sheets manufactured in examples and comparative examples were cut into pieces of 100mm×100mm, and the pieces were used as surface resistivity measurement samples. Ultraviolet (UV) was irradiated to the adhesive layer of the sample for measuring surface resistivity through a base material using an ultraviolet irradiation device (manufactured by LINTEC Corporation, product name "RAD-2000") (illuminance: 230 mW/cm) 2 Light amount: 190mJ/cm 2 ) The adhesive layer is cured. The sample for measuring surface resistivity after UV irradiation was subjected to humidity control at 23℃and 50% relative humidity for 24 hours, and then the release sheet was peeled off and measured at an applied voltage of 100V using a digital electrometer (manufactured by ADVANTEST Co.)The surface resistivity (Ω/≡) of the surface (adhesion surface) of the exposed adhesive layer side was determined. The results are shown in Table 2.
Figure BDA0003598504900000291
TABLE 2
Figure BDA0003598504900000301
As is clear from table 2, the workpiece processing sheet manufactured in examples has excellent antistatic properties, and also has excellent pickup properties and adhesion between the adhesive layer and the substrate even when used in a silicon wafer immediately after polishing. The workpiece processing sheets produced in examples 1 to 4 (the intermediate layer of the base material does not contain an antistatic agent) also have excellent cutting resistance.
Industrial applicability
The workpiece processing sheet of the present invention can be suitably used for processing a workpiece such as a semiconductor wafer.

Claims (11)

1. A workpiece processing sheet comprising a base material and an adhesive layer laminated on one surface side of the base material, characterized in that,
the substrate contains an antistatic agent and,
the adhesive layer is formed from an active energy ray-curable acrylic adhesive composition containing an acrylic polymer and a free epoxy resin,
the adhesive layer was cut into a slit from the surface side of the adhesive layer opposite to the base material after curing with a dicing blade, a dicing portion having a number of squares of 100 was formed such that the dicing distance was 5mm and the dicing line was 11×11 pieces according to the dicing method of JIS K5600-5-6:1999, an adhesive Tape made of cellose Tape (registered trademark) manufactured by nichiba co., ltd was attached to the dicing portion, and the number of squares remaining after peeling the adhesive Tape attached to the dicing portion was 95 or more.
2. The sheet for workpiece processing according to claim 1, wherein a surface resistivity of a surface of the adhesive layer opposite to the base material after the active energy ray curing is 1.0X10 13 Ω/≡or less.
3. The sheet for workpiece processing according to claim 1, wherein the content of the free epoxy resin in the acrylic adhesive composition is 5 parts by mass or more and less than 40 parts by mass relative to 100 parts by mass of the acrylic polymer.
4. The sheet for workpiece processing according to claim 1, wherein the acrylic adhesive composition contains a crosslinking agent.
5. The sheet for workpiece processing according to claim 4, wherein the content of the crosslinking agent in the acrylic adhesive composition is 3 parts by mass or more relative to 100 parts by mass of the acrylic polymer.
6. The sheet for workpiece processing according to claim 4, wherein the crosslinking agent is a toluene diisocyanate-based crosslinking agent.
7. The workpiece processing sheet according to claim 1, wherein,
the acrylic polymer is a (meth) acrylate polymer having a functional group having active energy ray curability introduced into a side chain,
the (meth) acrylic acid ester polymer contains, as the most monomer units constituting the main chain of the polymer, alkyl (meth) acrylate having 1 to 4 carbon atoms as an alkyl group.
8. The workpiece processing sheet according to claim 1, wherein,
the substrate has a surface layer adjacent to the adhesive layer, a back layer remote from the adhesive layer, and an intermediate layer between the surface layer and the back layer,
at least the surface layer contains an antistatic agent.
9. The workpiece processing sheet according to claim 8, wherein,
the surface layer and the back layer contain an antistatic agent,
the intermediate layer contains no antistatic agent, or the intermediate layer contains an antistatic agent in a unit of mass% that is less than the antistatic agent content in each of the surface layer and the back surface layer and less than 5 mass%.
10. The sheet for workpiece processing according to claim 1, wherein the antistatic agent is a polymer type antistatic agent.
11. The workpiece processing sheet according to any one of claims 1 to 10, wherein the workpiece processing sheet is a cut sheet.
CN202210414885.4A 2021-10-20 2022-04-15 Piece for workpiece processing Pending CN115991962A (en)

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