JP2023108420A - Sheet for workpiece processing - Google Patents

Abstract

To provide a sheet for workpiece processing capable of preferably executing pickup, and suppressing flying of the chip.SOLUTION: There is provided a sheet for workpiece processing comprising: a substrate; and an adhesive layer laminated on one surface side on the substrate. The adhesive layer is formed of an adhesive composition containing: an acrylic polymer in which an active energy ray-curable group is introduced to a side chain; and an alkylene glycol component which is at least one kind out of polyethylene glycol and polytetramethylene ether glycol and whose number average molecular weight is 200 or greater and 3000 or smaller.SELECTED DRAWING: None

Description

TECHNICAL FIELD The present invention relates to a work processing sheet used for processing a work such as a semiconductor wafer.

Semiconductor wafers made of silicon, gallium arsenide, etc. and various types of packages are manufactured in a state of large diameter, cut into chips (diced), separated (picked up), and then transferred to the next process, the mounting process. At this time, the workpiece such as a semiconductor wafer is subjected to back grinding, dicing, cleaning, and the like while being laminated on an adhesive sheet having a base material and an adhesive layer (hereinafter sometimes referred to as a "workpiece processing sheet"). Processing such as drying, expanding, picking up, and mounting is performed.

As an example of the work processing sheet, Patent Document 1 discloses a work processing sheet provided with an adhesive layer containing a predetermined component. In particular, Patent Document 1 describes certain polyoxypropylene-glyceryl ether (paragraph 0041 of Patent Document 1, etc.), polyoxypropylene-diglyceryl ether (0044, etc. of Patent Document 1) or polyoxypropylene-sorbit (Patent Document 1). No. 1, 0045, etc.) is disclosed.

Patent No. 5764519

In the pick-up process described above, generally, the chip is pushed up over the work processing sheet from the back side of the chip, and at the same time, the chip is picked up while being sucked by a vacuum collet. At this time, from the viewpoint of efficiency and prevention of damage to the tip, it is preferable that the tip can be picked up without requiring excessive pushing up or excessive suction. In particular, in recent years, as workpieces have become thinner and chip sizes have been reduced, there has been a demand for better pick-up performance. However, the conventional work processing sheet as disclosed in Patent Document 1 cannot sufficiently meet such a demand for pickup.

In addition, in the above-described dicing process, it is required that the formed chips do not fall off from the work processing sheet and scatter due to the impact of dicing (hereinafter sometimes referred to as "chip flying"). be done.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a work processing sheet that enables excellent pick-up and prevents chips from flying.

In order to achieve the above objects, firstly, the present invention provides a work processing sheet comprising a substrate and an adhesive layer laminated on one side of the substrate, wherein the adhesive layer An acrylic polymer having an active energy ray-curable group introduced into the chain, and an alkylene glycol-based component having a number average molecular weight of 200 or more and 3000 or less, which is at least one of polyethylene glycol and polytetramethylene ether glycol. Provided is a work processing sheet formed from a pressure-sensitive adhesive composition (Invention 1).

In the work processing sheet according to the invention (invention 1), the adhesive layer is formed from the adhesive composition containing the alkylene glycol-based component described above, so that when the chips are picked up, the chips The adhesion of the work processing sheet to the surface is moderately lowered. Further, the adhesive composition contains an acrylic polymer in which an active energy ray-curable group is introduced into the side chain, so that the adhesive force of the work processing sheet to the chip is reduced by the irradiation of the active energy ray. can also As a result, the workpiece processing sheet does not require excessive pushing up or excessive suction by a vacuum collet, and the chips can be easily picked up. On the other hand, since the adhesion of the adhesive layer to the chips is not excessively lowered, chip flying is well suppressed during dicing even when impact or the like is caused by dicing.

In the above invention (Invention 1), the pressure-sensitive adhesive composition contains the polyethylene glycol as the alkylene glycol-based component, and the content of the polyethylene glycol in the pressure-sensitive adhesive composition is such that the side chain has an active energy ray It is preferably 0.001 parts by mass or more and 2 parts by mass or less with respect to 100 parts by mass of the acrylic polymer into which the curable group is introduced (Invention 2).

In the above inventions (inventions 1 and 2), the pressure-sensitive adhesive composition contains the polytetramethylene ether glycol as the alkylene glycol-based component, and the content of the polytetramethylene ether glycol in the pressure-sensitive adhesive composition is It is preferably 0.001 parts by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the acrylic polymer having active energy ray-curable groups introduced into the side chains (Invention 3).

In the work processing sheet according to the above invention (invention 4), the adhesive layer is formed from the adhesive composition containing a predetermined amount of the polypropylene glycol described above, so that when picking up the chip, the chip The adhesion of the work processing sheet to the surface is moderately lowered. Further, the adhesive composition contains an acrylic polymer in which an active energy ray-curable group is introduced into the side chain, so that the adhesive force of the work processing sheet to the chip is reduced by the irradiation of the active energy ray. can also As a result, the workpiece processing sheet does not require excessive pushing up or excessive suction by a vacuum collet, and the chips can be easily picked up. On the other hand, since the adhesion of the adhesive layer to the chips is not excessively lowered, chip flying is well suppressed during dicing even when impact or the like is caused by dicing.

The second aspect of the present invention is a work processing sheet comprising a substrate and an adhesive layer laminated on one side of the substrate, wherein the adhesive layer has an active energy ray-curable group on a side chain. and an acrylic polymer into which is introduced and a pressure-sensitive adhesive composition containing an alkylene glycol-based component having a number average molecular weight of 200 or more and 3000 or less, which is polypropylene glycol, and the alkylene glycol-based component The content in the pressure-sensitive adhesive composition is 0.001 parts by mass or more and 2 parts by mass or less with respect to 100 parts by mass of the acrylic polymer having an active energy ray-curable group introduced into the side chain. (Invention 4).

In the above inventions (inventions 1 to 4), it is preferable that the work processing sheet is used as at least one of a dicing sheet and a pickup sheet (invention 5).

According to the work processing sheet of the present invention, it is possible to pick up the workpiece satisfactorily, and chip flying is less likely to occur.

Embodiments of the present invention will be described below.
A work processing sheet according to this embodiment includes a substrate and an adhesive layer laminated on one side of the substrate.

1. Structural Members of Work Processing Sheet (1) Base Material The base material in the present embodiment is not particularly limited as long as it exhibits the desired functions when the work processing sheet is used. In particular, the base material is preferably a resin film containing a resin-based material as a main material. Specific examples thereof include polyolefin films such as polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, ethylene-norbornene copolymer film, norbornene resin film; polyethylene terephthalate film, polybutylene terephthalate film, polyethylene Polyester film such as naphthalate; ethylene-vinyl acetate copolymer film; ethylene-(meth)acrylic acid copolymer film, ethylene-(meth)acrylic acid copolymer film, other ethylene-(meth)acrylic Ethylene copolymer films such as acid ester copolymer films; polyvinyl chloride films such as polyvinyl chloride films and vinyl chloride copolymer films; (meth)acrylic acid ester copolymer films; polyurethane films; polyimide films; polystyrene film; polycarbonate film; fluorine resin film; Modified films such as these crosslinked films and ionomer films are also used. Further, the base material may be a laminated film formed by laminating a plurality of films described above. In this laminated film, the materials constituting each layer may be of the same type or of different types.

Among the above, it is preferable to use at least one of polyolefin film and ethylene copolymer film, and it is particularly preferable to use ethylene-(meth)acrylic acid copolymer film. In addition, "(meth)acrylic acid" in this specification means both acrylic acid and methacrylic acid. The same is true for other similar terms. In addition, the term "polymer" used herein also includes the concept of "copolymer".

The substrate may contain various additives such as flame retardants, plasticizers, antistatic agents, lubricants, antioxidants, colorants, infrared absorbers, ultraviolet absorbers, and ion scavengers. Although the content of these additives is not particularly limited, it is preferably within a range in which the base material exhibits the desired functions.

The surface of the base material on which the pressure-sensitive adhesive layer is to be laminated may be subjected to surface treatment such as primer treatment, corona treatment, plasma treatment, etc., in order to enhance adhesion with the pressure-sensitive adhesive layer.

The thickness of the base material can be appropriately set according to the method in which the work processing sheet is used, but is preferably, for example, 200 μm or less, and particularly preferably 150 μm or less. Moreover, the thickness of the substrate is preferably 10 μm or more, and particularly preferably 25 μm or more.

(2) Adhesive layer The adhesive layer in the present embodiment is, as one aspect, an acrylic polymer having an active energy ray-curable group introduced into a side chain, and at least one of polyethylene glycol and polytetramethylene ether glycol. It is formed from a pressure-sensitive adhesive composition containing a seed, an alkylene glycol component having a number average molecular weight of 200 or more and 3000 or less.

In another aspect, the pressure-sensitive adhesive layer in the present embodiment is composed of an acrylic polymer having an active energy ray-curable group introduced into a side chain and polypropylene glycol having a number average molecular weight of 200 or more and 3000 or less. The content of the alkylene glycol-based component in the adhesive composition is, with respect to 100 parts by mass of the acrylic polymer, It is 0.001 parts by mass or more and 2 parts by mass or less.

Since the adhesive layer of the work processing sheet according to the present embodiment is formed from the above-described adhesive composition, it is possible to perform good pickup. In particular, by using an acrylic polymer having active energy ray-curable groups introduced into side chains, the pressure-sensitive adhesive layer exhibits active energy ray-curable properties. Therefore, by irradiating the adhesive layer with an active energy ray, it is possible to favorably reduce the adhesive force to the work. Furthermore, the adhesion between the pressure-sensitive adhesive layer and the workpiece moderately decreases due to the use of the above-mentioned alkylene glycol-based component. As a result, with the work processing sheet according to the present embodiment, it is possible to easily pick up the work, and it is possible to suppress damage to the work and decrease in production efficiency due to pick-up failure.

In particular, the alkylene glycol-based component in the present embodiment is, as described above, at least one of polyethylene glycol and polytetramethylene ether glycol, or polypropylene glycol having a number average molecular weight of 200 or more and 3000 or less. By using such an alkylene glycol-based component, the adhesiveness between the pressure-sensitive adhesive layer and the workpiece can be moderately lowered, and good pick-up can be achieved. Some polypropylene glycols are prone to oxidative deterioration, and work processing sheets using such polypropylene glycols are inferior in long-term storage stability, their inherent performance is lowered, and desired pick-up properties cannot be obtained. There is a problem. However, polyethylene glycol and polytetramethylene ether glycol used in the present embodiment, and polypropylene glycol having a number average molecular weight of 200 or more and 3000 or less can avoid such problems.

Furthermore, since the adhesive layer formed from the above-described adhesive composition does not excessively deteriorate the adhesiveness of the adhesive layer to the chip, it is possible to effectively suppress unintended detachment of the formed chip. be able to. In particular, even when the dicing blade comes into contact with the wafer or the work processing sheet during dicing and impact is generated, the detachment of the chip from the work processing sheet, that is, the chip flying can be suppressed satisfactorily. can.

Further, the alkylene glycol-based component in the present embodiment has a number average molecular weight of 200 or more and 3000 or less as described above. In particular, an alkylene glycol-based component having a number average molecular weight of 3,000 or less dissolves well in a solvent, thereby making it possible to obtain a desired adhesive composition coating liquid. By using the coating liquid, it is possible to form a pressure-sensitive adhesive layer having a desired thickness and smoothness. In addition, the number average molecular weight (Mw) mentioned above is the value of standard polystyrene conversion measured by the gel permeation chromatography method (GPC method).

(2-1) Acrylic polymer having active energy ray-curable groups introduced into side chains Acrylic polymers having active energy ray-curable groups introduced into side chains in the present embodiment (hereinafter “active energy ray-curable is not particularly limited, and for example, an acrylic copolymer (a1) having a functional group-containing monomer unit and a functional group that binds to the functional group It is preferably obtained by reacting with the unsaturated group-containing compound (a2).

The acrylic copolymer (a1) preferably contains a structural unit derived from a functional group-containing monomer and a structural unit derived from a (meth)acrylic acid ester monomer or a derivative thereof.

The functional group-containing monomer as a structural unit of the acrylic copolymer (a1) has a polymerizable double bond and a functional group such as a hydroxy group, a carboxyl group, an amino group, a substituted amino group, an epoxy group, etc. in the molecule. is preferably a monomer having

Examples of hydroxy group-containing monomers include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 3-hydroxybutyl ( meth)acrylate, 4-hydroxybutyl (meth)acrylate and the like, and these may be used alone or in combination of two or more.

Carboxy group-containing monomers include, for example, ethylenically unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid, and citraconic acid. These may be used alone or in combination of two or more.

Examples of amino group-containing monomers or substituted amino group-containing monomers include aminoethyl (meth)acrylate and n-butylaminoethyl (meth)acrylate. These may be used alone or in combination of two or more.

When the acrylic copolymer (a1) contains the functional group-containing monomer, the mass ratio of the structural portion derived from the functional group-containing monomer in the acrylic copolymer (a1) is 5% by mass or more. is preferred, particularly preferably 10% by mass or more, and more preferably 15% by mass or more. The above proportion is preferably 45% by mass or less, particularly preferably 40% by mass or less, and further preferably 35% by mass or less. When the ratio of the structural portion derived from the functional group-containing monomer is within the above range, it becomes easier to adjust the introduction amount of the unsaturated group-containing compound (a2) to a suitable range.

As the (meth)acrylic acid ester monomer constituting the acrylic copolymer (a1), an alkyl (meth)acrylate having an alkyl group with 1 to 20 carbon atoms is preferably used.

Examples of alkyl (meth)acrylates include alkyl (meth)acrylates in which the alkyl group has 1 to 18 carbon atoms, such as methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl ( Meth)acrylate, 2-ethylhexyl (meth)acrylate and the like are preferably used. These may be used individually by 1 type, and may be used in combination of 2 or more type.

When the acrylic copolymer (a1) contains the (meth)acrylic acid ester monomer, the mass ratio of the structural portion derived from the (meth)acrylic acid ester monomer in the acrylic copolymer (a1) is 55. It is preferably at least 60% by mass, more preferably at least 65% by mass. The above proportion is preferably 95% by mass or less, particularly preferably 90% by mass or less, and further preferably 85% by mass or less. When the ratio of the structural portion derived from the (meth)acrylic acid ester monomer is within the above range, the desired adhesive strength can be easily exhibited.

The acrylic copolymer (a1) may contain components other than the monomers described above as constituent monomers, such as dimethylacrylamide, vinyl formate, vinyl acetate, styrene, and monomers having an alicyclic structure. may contain.

An active energy ray-curable polymer ( A) is obtained.

The functional group of the unsaturated group-containing compound (a2) can be appropriately selected according to the type of functional group of the functional group-containing monomer unit of the acrylic copolymer (a1). For example, when the functional group possessed by the acrylic copolymer (a1) is a hydroxy group, an amino group or a substituted amino group, the functional group possessed by the unsaturated group-containing compound (a2) is preferably an isocyanate group or an epoxy group. When the functional group possessed by the system copolymer (a1) is an epoxy group, the functional group possessed by the unsaturated group-containing compound (a2) is preferably an amino group, a carboxyl group or an aziridinyl group.

In addition, the unsaturated group-containing compound (a2) contains at least 1, preferably 1 to 6, more preferably 1 to 4 energy ray-polymerizable carbon-carbon double bonds per molecule. is Specific examples of such unsaturated group-containing compounds (a2) include, for example, 2-(meth)acryloyloxyethyl isocyanate, meta-isopropenyl-α,α-dimethylbenzyl isocyanate, (meth)acryloyl isocyanate, and allyl isocyanate. , 1,1-(bisacryloyloxymethyl)ethyl isocyanate; a diisocyanate compound or polyisocyanate compound, an acryloyl monoisocyanate compound obtained by reacting hydroxyethyl (meth)acrylate; a diisocyanate compound or polyisocyanate compound, and a polyol compound , acryloyl monoisocyanate compound obtained by reaction with 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.

The amount of the unsaturated group-containing compound (a2) is preferably 40 mol% or more, particularly 50 mol% or more, based on the amount of functional groups possessed by the acrylic copolymer (a1). preferable. In addition, the amount of the unsaturated group-containing compound (a2) is preferably 99 mol% or less, particularly 95% or less, based on the amount of functional groups possessed by the acrylic copolymer (a1). is preferred, and more preferably 90 mol % or less.

In the reaction between the acrylic copolymer (a1) and the unsaturated group-containing compound (a2), the functional group of the acrylic copolymer (a1) and the functional group of the unsaturated group-containing compound (a2) Depending on the combination, reaction temperature, pressure, solvent, time, the presence or absence of a catalyst, and the type of catalyst can be appropriately selected. As a result, the functional groups present in the acrylic copolymer (a1) react with the functional groups in the unsaturated group-containing compound (a2), and the unsaturated groups in the acrylic copolymer (a1) It is introduced into the side chain to obtain the energy ray-curable polymer (A).

In particular, the catalyst used for the reaction between the acrylic copolymer (a1) and the unsaturated group-containing compound (a2) is at least one selected from organic tin compounds, zirconium complexes, zinc complexes and zirconium-containing metal soaps. It is preferably carried out in the presence of an organometallic catalyst of some kind. By using such an organometallic catalyst, the pressure-sensitive adhesive layer and the base material can easily exhibit excellent adhesion, and the separation of the base material and the pressure-sensitive adhesive layer during use can be easily suppressed.

Examples of the above organotin compounds include dibutyltin dilaurate (DBTDL), dioctyltin dilaurate (DOTDL), dibutyltin diacetate (DBTDA), dioctyltin diacetate (DOTDA), dioctyltin maleate (DOTTM), dibutyltin maleate ( DBTM) and the like. Among these, it is preferable to use dibutyltin dilaurate (DBTDL).

When an organic tin compound is used as the organometallic catalyst, the content of the organic tin compound in the adhesive composition is 0.00 parts per 100 parts by mass of the total amount of monomers constituting the acrylic copolymer (a1). 001 parts by mass or more, particularly preferably 0.01 parts by mass or more, and more preferably 0.02 parts by mass or more. Also, the content is preferably less than 0.13 parts by mass, particularly preferably 0.1 parts by mass or less, and more preferably 0.07 parts by mass or less.

The weight average molecular weight (Mw) of the active energy ray-curable polymer (A) thus obtained is preferably 100,000 or more, particularly preferably 200,000 or more, further preferably 300,000 or more. Preferably. Also, the weight average molecular weight (Mw) is preferably 1,200,000 or less, particularly preferably 1,000,000 or less, and further preferably 800,000 or less. In addition, the weight average molecular weight (Mw) in this specification is the value of standard polystyrene conversion measured by the gel permeation chromatography method (GPC method).

(2-2) Alkylene Glycol-Based Component As described above, the alkylene glycol-based component in the present embodiment is at least one of polyethylene glycol and polytetramethylene ether glycol, or polypropylene glycol. The number of functional groups (hydroxy groups present at the terminals) of the alkylene glycol-based component in the present embodiment is two.

Further, the alkylene glycol-based component in the present embodiment has a number average molecular weight of 200 or more and 3000 or less as described above. The number average molecular weight is preferably 250 or more, more preferably 300 or more. Further, the number average molecular weight is more preferably 2,200 or less, particularly preferably 2,000 or less, further preferably 1,000 or less.

When the pressure-sensitive adhesive composition in the present embodiment contains polyethylene glycol as an alkylene glycol-based component, the content of the polyethylene glycol in the pressure-sensitive adhesive composition is 100 parts by mass of the active energy ray-curable polymer (A). On the other hand, it is preferably 0.001 parts by mass or more, particularly preferably 0.005 parts by mass or more, further preferably 0.01 parts by mass or more. Also, the content is preferably 2 parts by mass or less, particularly preferably 1 part by mass or less, and further preferably 0.5 parts by mass or less. When the content of polyethylene glycol is within the above range, it is possible to satisfactorily suppress chip flying before irradiation with active energy rays, while the adhesive force is easily reduced sufficiently after irradiation with active energy rays, resulting in a better result. It becomes easier to perform a good pickup.

Further, when the pressure-sensitive adhesive composition in the present embodiment contains polytetramethylene ether glycol as an alkylene glycol-based component, the content of the polytetramethylene ether glycol in the pressure-sensitive adhesive composition is It is preferably 0.001 parts by mass or more, particularly preferably 0.05 parts by mass or more, and further preferably 0.1 parts by mass or more, based on 100 parts by mass of coalescence (A). Moreover, the content is preferably 10 parts by mass or less, particularly preferably 8 parts by mass or less, and further preferably 6 parts by mass or less. When the content of the polytetramethylene ether glycol is within the above range, it is possible to satisfactorily suppress chip flying before irradiation with active energy rays, and at the same time, it becomes easy to sufficiently reduce adhesive strength after irradiation with active energy rays. , which facilitates better pickup.

When the pressure-sensitive adhesive composition in the present embodiment contains polypropylene glycol, the content of the polypropylene glycol in the pressure-sensitive adhesive composition is 0.00 per 100 parts by mass of the active energy ray-curable polymer (A). 001 parts by mass or more and 2 parts by mass or less. From the viewpoint of facilitating compatibility between chip flying and pick-up performance at a higher level, the content is preferably 0.005 parts by mass or more, and particularly preferably 0.01 parts by mass or more. Also, from the same viewpoint, the content is preferably 1 part by mass or less, and particularly preferably 0.5 parts by mass or less.

(2-3) Crosslinking agent The pressure-sensitive adhesive composition in the present embodiment preferably contains a crosslinking agent. When the pressure-sensitive adhesive composition contains a cross-linking agent, the active energy ray-curable polymer (A) can be cross-linked in the pressure-sensitive adhesive layer to form a good three-dimensional network structure. As a result, the cohesive force of the resulting pressure-sensitive adhesive is further improved, and it is possible to effectively suppress the occurrence of adhesive residue on the workpiece separated from the workpiece processing sheet after irradiation with the active energy ray. In addition, when the pressure-sensitive adhesive composition contains a cross-linking agent, the acrylic copolymer (a1) preferably contains the functional group-containing monomer described above as a monomer unit constituting the polymer. It is preferable to contain a functional group-containing monomer having a highly reactive functional group with the cross-linking agent used.

Examples of the above-mentioned cross-linking agents include isocyanate-based cross-linking agents, epoxy-based cross-linking agents, amine-based cross-linking agents, melamine-based cross-linking agents, aziridine-based cross-linking agents, hydrazine-based cross-linking agents, aldehyde-based cross-linking agents, oxazoline-based cross-linking agents, and metal alkoxides. cross-linking agents, metal chelate-based cross-linking agents, metal salt-based cross-linking agents, ammonium salt-based cross-linking agents, and the like. These cross-linking agents can be selected according to the functional group derived from the functional group-containing monomer that the acrylic copolymer has. In addition, these crosslinking agents can be used individually by 1 type or in combination of 2 or more types.

The isocyanate-based cross-linking agent contains at least a polyisocyanate compound. Examples of polyisocyanate compounds include aromatic polyisocyanates such as tolylene diisocyanate, diphenylmethane diisocyanate, and xylylene diisocyanate; aliphatic polyisocyanates such as hexamethylene diisocyanate; and alicyclic polyisocyanates such as isophorone diisocyanate and hydrogenated diphenylmethane diisocyanate. , and their biuret, isocyanurate, and adducts which are reaction products with low-molecular-weight active hydrogen-containing compounds such as ethylene glycol, propylene glycol, neopentyl glycol, trimethylolpropane, and castor oil. Among these, trimethylolpropane-modified aromatic polyisocyanate, particularly trimethylolpropane-modified tolylene diisocyanate is preferable.

When the pressure-sensitive adhesive composition in the present embodiment contains a cross-linking agent, the content of the cross-linking agent in the pressure-sensitive adhesive composition is 0.1 mass with respect to 100 parts by mass of the active energy ray-curable polymer (A). It is preferably at least 1 part by mass, particularly preferably at least 0.5 part by mass, further preferably at least 1 part by mass. Moreover, the content is preferably 20 parts by mass or less, and particularly preferably 5 parts by mass or less. When the content of the cross-linking agent is 0.1 parts by mass or more, it becomes easier to improve the cohesive force of the pressure-sensitive adhesive layer after irradiation with active energy rays, thereby effectively suppressing adhesive residue. becomes. In addition, when the content of the cross-linking agent is 20 parts by mass or less, the degree of cross-linking becomes appropriate, and the pressure-sensitive adhesive layer easily exhibits desired adhesive strength.

(2-4) Photopolymerization Initiator The adhesive composition in the present embodiment preferably contains a photopolymerization initiator. By including a photopolymerization initiator in the pressure-sensitive adhesive composition, it is possible to reduce the polymerization curing time and the amount of light irradiation when the pressure-sensitive adhesive layer is cured by irradiation with active energy rays.

Examples of photoinitiators include benzophenone, acetophenone, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzoin benzoic acid, benzoin methyl benzoate, benzoin dimethyl ketal, 2,4-diethylthio xanthone, 1-hydroxycyclohexylphenyl ketone, benzyldiphenylsulfide, tetramethylthiuram monosulfide, azobisisobutyronitrile, benzyl, dibenzyl, diacetyl, β-chloranthraquinone, (2,4,6-trimethylbenzyldiphenyl) phosphine oxide, 2-benzothiazole-N,N-diethyldithiocarbamate, oligo{2-hydroxy-2-methyl-1-[4-(1-propenyl)phenyl]propanone}, 2,2-dimethoxy-1, 2-diphenylethan-1-one, 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]phenyl}-2-methyl-propan-1-one and the like be done. Among these, 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]phenyl}-2-methyl-propan-1-one is preferably used. The photopolymerization initiators described above may be used alone, or two or more of them may be used in combination.

When the pressure-sensitive adhesive composition in the present embodiment contains a photopolymerization initiator, the content of the photopolymerization initiator in the pressure-sensitive adhesive composition is, relative to 100 parts by mass of the active energy ray-curable polymer (A), It is preferably 0.1 parts by mass or more, particularly preferably 1 part by mass or more. Also, the content is preferably 10 parts by mass or less, particularly preferably 5 parts by mass or less. When the content of the photopolymerization initiator is within the above range, the adhesive layer can be efficiently cured by irradiation with active energy rays, thereby improving the adhesive strength of the work processing sheet to the adherend. It becomes easy to lower to

(2-5) Other components The pressure-sensitive adhesive composition in the present embodiment contains desired additives, such as silane coupling agents and antistatic agents, as long as they do not impair the above-described effects of the work processing sheet according to the present embodiment. , tackifiers, antioxidants, light stabilizers, softeners, fillers, refractive index modifiers and the like can be added.

(2-6) Method for preparing an adhesive composition The adhesive composition in the present embodiment is obtained by producing an active energy ray-curable polymer (A) and obtaining the active energy ray-curable polymer (A). , an alkylene glycol-based component, and, if desired, a cross-linking agent, a photopolymerization initiator, and an additive. At this time, if desired, a diluent solvent may be added to obtain a coating liquid of the adhesive composition.

Examples of the diluting solvent include aliphatic hydrocarbons such as hexane, heptane and cyclohexane; aromatic hydrocarbons such as toluene and xylene; halogenated hydrocarbons such as methylene chloride and ethylene chloride; Alcohols such as 1-methoxy-2-propanol, ketones such as acetone, methyl ethyl ketone, 2-pentanone, isophorone and cyclohexanone, esters such as ethyl acetate and butyl acetate, and cellosolve solvents such as ethyl cellosolve are used.

The concentration and viscosity of the coating liquid prepared in this manner are not particularly limited as long as they are within a range that allows coating, and can be appropriately selected according to the situation. For example, it is diluted so that the concentration of the adhesive composition is 10% by mass or more and 60% by mass or less. When obtaining the coating liquid, the addition of a diluent solvent or the like is not a necessary condition, and the diluent solvent may not be added as long as the viscosity of the adhesive composition allows coating. In this case, the adhesive composition becomes a coating liquid in which the polymerization solvent for the acrylic copolymer (a1) is used as the diluting solvent.

(2-7) Thickness of Adhesive Layer The thickness of the adhesive layer in the present embodiment is preferably 1 μm or more, particularly preferably 3 μm or more, further preferably 5 μm or more. When the thickness of the pressure-sensitive adhesive layer is 1 μm or more, the work processing sheet can easily exhibit good adhesive strength, and chip flying can be more easily suppressed. Moreover, the thickness is preferably 50 μm or less, particularly preferably 30 μm or less, further preferably 20 μm or less. When the thickness of the pressure-sensitive adhesive layer is 30 μm or less, it becomes easier to pick up the workpiece.

(3) Release sheet In the work processing sheet according to the present embodiment, until the surface of the adhesive layer opposite to the base material (hereinafter sometimes referred to as "adhesive surface") is attached to the work, A release sheet may be laminated on the surface for the purpose of protecting the surface.

The configuration of the release sheet is arbitrary, and an example thereof is a plastic film subjected to 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, and polyolefin films such as polypropylene and polyethylene. As the release agent, a silicone-based, fluorine-based, long-chain alkyl, rubber-based, or the like can be used.

The thickness of the release sheet is not particularly limited, and may be, for example, 16 μm or more and 250 μm or less.

(4) Others In the work processing sheet according to the present embodiment, an adhesive layer may be laminated on the surface of the adhesive layer opposite to the base material. In this case, the work processing sheet according to this embodiment can be used as a dicing/die bonding sheet. In the sheet, a work is attached to the surface of the adhesive layer opposite to the adhesive layer, and the adhesive layer is diced together with the work to obtain a chip laminated with the individualized adhesive layer. be able to. The chip can be easily fixed to a target on which the chip is mounted by means of the individualized adhesive layer. Examples of the material constituting the adhesive layer include those containing a thermoplastic resin and a low-molecular-weight thermosetting adhesive component, those containing a B-stage (semi-cured) thermosetting adhesive component, and the like. It is preferable to use

In addition, in the work processing sheet according to the present embodiment, a protective film-forming layer may be laminated on the adhesive surface of the adhesive layer. In this case, the work processing sheet according to this embodiment can be used as a protective film-forming and dicing sheet. In such a sheet, a work is attached to the surface of the protective film-forming layer opposite to the adhesive layer, and the protective film-forming layer is diced together with the work, so that the individualized protective film-forming layer is laminated. you can get the chips As the work, one having a circuit formed on one side is preferably used. In this case, a protective film-forming layer is usually laminated on the side opposite to the side on which the circuit is formed. By curing the individualized protective film-forming layer at a predetermined timing, a protective film having sufficient durability can be formed on the chip. The protective film-forming layer is preferably made of an uncured curable adhesive.

2. Physical properties of the work processing sheet According to the present embodiment, the work processing sheet has an adhesive force of 1000 mN/25 mm or more to a silicon wafer (mirror surface of a mirror-finished silicon wafer, the same shall apply hereinafter) before irradiation with an active energy ray. It is preferably 1500 mN/25 mm or more, and more preferably 2000 mN/25 mm or more. Since the adhesive force to the silicon wafer before irradiation with active energy rays is 1000 mN / 25 mm or more, it becomes easy to fix the workpiece well on the workpiece processing sheet, and unintended workpieces (especially workpieces after singulation) fall off. (Particularly, chip flying) can be easily prevented satisfactorily. Although the upper limit of the adhesive strength is not particularly limited, for example, it is preferably 20000 mN/25 mm or less, particularly preferably 10000 mN/25 mm or less, and further preferably 7000 mN/25 mm or less. Further, the details of the method for measuring the adhesive strength are as described in the test examples described later.

In addition, in the work processing sheet according to the present embodiment, the adhesive force to the silicon wafer after irradiation with active energy rays is preferably 90 mN/25 mm or less, particularly preferably 80 mN/25 mm or less, and further preferably 70 mN. /25 mm or less. In the work processing sheet according to the present embodiment, the pressure-sensitive adhesive layer is formed from a pressure-sensitive adhesive composition containing an acrylic polymer having an active energy ray-curable group introduced into the side chain and the above-described alkylene glycol-based component. As a result, it becomes easy to achieve the adhesive strength as described above after irradiation with active energy rays. When the adhesive force to the work after irradiation with the active energy ray is 90 mN/25 mm or less, the work can be easily separated from the work processing sheet. Further, the adhesive strength to the silicon wafer after irradiation with active energy rays is preferably 10 mN/25 mm or more, particularly preferably 15 mN/25 mm or more, and further preferably 20 mN/25 mm or more. This makes it easier to suppress separation/dropping of the workpiece at an unintended stage after irradiation with the active energy ray. In addition, the details of the method for measuring the adhesive strength are as described in the test examples described later.

3. Method for Manufacturing Work Processing Sheet The method for manufacturing the work processing sheet according to the present embodiment is not particularly limited, and is preferably manufactured by laminating an adhesive layer on one side of a substrate.

Lamination of the pressure-sensitive adhesive layer on one side of the substrate can be performed by a known method. For example, it is preferable to transfer the pressure-sensitive adhesive layer formed on the release sheet to one side of the substrate. In this case, the pressure-sensitive adhesive composition constituting the pressure-sensitive adhesive layer and, if desired, a coating solution containing a solvent or a dispersion medium is prepared, and the release-treated surface of the release sheet (hereinafter sometimes referred to as "release surface") ) on the adhesive layer by applying the coating liquid with a die coater, curtain coater, spray coater, slit coater, knife coater, applicator or the like to form a coating film and drying the coating film. can be formed. The properties of the coating liquid are not particularly limited as long as the coating liquid can be applied. The release sheet in this laminate may be released as a process material, or may be used to protect the adhesive surface of the adhesive layer until the work processing sheet is attached to the adherend.

When the coating liquid for forming the pressure-sensitive adhesive layer contains a cross-linking agent, by changing the above drying conditions (temperature, time, etc.) or by separately providing heat treatment, the inside of the coating film A crosslinking reaction between the acrylic copolymer and the crosslinking agent is allowed to proceed to form a crosslinked structure with a desired existence density in the pressure-sensitive adhesive layer. In order to allow the cross-linking reaction to proceed sufficiently, after laminating the pressure-sensitive adhesive layer on the base material by the method described above, the obtained work processing sheet is placed in an environment of, for example, 23° C. and a relative humidity of 50% for several days. Curing such as leaving still may be performed.

Instead of transferring the pressure-sensitive adhesive layer formed on the release sheet to one side of the substrate as described above, the pressure-sensitive adhesive layer may be formed directly on the substrate. In this case, the adhesive layer is formed by applying the coating liquid for forming the adhesive layer described above to one side of the substrate to form a coating film, and drying the coating film.

4. Method of Using Work Processing Sheet The work processing sheet according to the present embodiment can be used for processing a work such as a semiconductor wafer. That is, after the adhesive surface of the work processing sheet according to the present embodiment is attached to the work, the work can be processed on the work processing sheet. Depending on the processing, the work processing sheet according to the present embodiment is used as a back grinding sheet, a dicing sheet, an expanding sheet, a pick-up sheet, or the like. Examples of the workpiece include semiconductor members such as semiconductor wafers and semiconductor packages, and glass members such as glass plates.

As described above, the work processing sheet according to the present embodiment can satisfactorily suppress chip flying of chips obtained by singulating a work such as a semiconductor wafer, and can satisfactorily pick up the chips. The chips may be obtained by dicing on another sheet and transferred onto the work processing sheet according to the present embodiment, or may be obtained by transferring the chips onto the work processing sheet according to the present embodiment. It may be obtained by dicing with. Therefore, the work processing sheet according to the present embodiment is particularly suitable for use as at least one of a dicing sheet and a pick-up sheet.

When the work processing sheet according to the present embodiment includes the above-described adhesive layer, the work processing sheet can be used as a dicing/die bonding sheet. Furthermore, when the work processing sheet according to the present embodiment includes the protective film forming layer described above, the work processing sheet can be used as a protective film forming and dicing sheet.

Further, since the adhesive layer in the work processing sheet according to the present embodiment exhibits active energy ray curability, it is also preferable to irradiate the following active energy ray during use. That is, it is preferable to irradiate the adhesive layer with an active energy ray before separating the processed work from the work processing sheet. As a result, the adhesive layer is cured, the adhesive strength of the adhesive sheet to the work after processing is favorably reduced, and the work after processing can be easily separated.

The embodiments described above are described to facilitate understanding of the present invention, and are not described to limit the present invention. Therefore, each element disclosed in the above embodiment is meant to include all design changes and equivalents that fall within the technical scope of the present invention.

For example, another layer may be provided between the substrate and the adhesive layer, or on the surface of the substrate opposite to the adhesive layer.

EXAMPLES The present invention will be described in more detail with reference to Examples and the like, but the scope of the present invention is not limited to these Examples and the like.

[Example 1]
(1) Production of base material Ethylene-methacrylic acid copolymer (EMAA) (manufactured by Mitsui DuPont Polychemicals, product name “Nucrel N0903HC”) is used with a small T-die extruder (manufactured by Toyo Seiki Seisakusho, product name “ An EMAA film with a thickness of 80 μm was obtained by extrusion molding with a Labo Plastomill”). The EMAA film was used as a substrate.

(2) Preparation of Adhesive Composition 62 parts by mass of n-butyl acrylate, 10 parts by mass of methyl methacrylate, and 28 parts by mass of 2-hydroxyethyl acrylate are polymerized by a solution polymerization method to obtain an acrylic copolymer. got a union. When the weight average molecular weight of the acrylic copolymer was measured by the method described later, it was 500,000.

Subsequently, methyl ethyl ketone was added to the resulting solution to adjust the solid content concentration to 35% by mass. Then, to the solution, 2-methacryloyloxyethyl isocyanate (MOI) is added in an amount corresponding to 80 mol% of 2-hydroxyethyl acrylate constituting the acrylic copolymer, and a tin-containing catalyst is added. 0.15 parts by mass of dibutyltin dilaurate (DBTDL) was added to 100 parts by mass of the total amount of the above monomers. After that, a reaction was carried out at 50° C. for 24 hours to obtain a (meth)acrylic acid ester polymer (active energy ray-curable polymer) having active energy ray-curable groups introduced into side chains. When the weight average molecular weight of the active energy ray-curable polymer was measured by the method described later, it was 500,000.

100 parts by mass of the obtained active energy ray-curable polymer (in terms of solid content, the same shall apply hereinafter) and 1.07 mass of trimethylolpropane-modified tolylene diisocyanate (manufactured by Tosoh Corporation, product name "Coronate L") as a cross-linking agent. and 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]phenyl}-2-methyl-propan-1-one (IGM Resins company, product name "Omnilad 127") and 0.14 parts by mass of polyethylene glycol with a number average molecular weight of 300 as an alkylene glycol component (manufactured by Toho Chemical Industry Co., Ltd., product name "PEG300") in a solvent. to obtain a coating liquid (solid concentration: 25% by mass) of the pressure-sensitive adhesive composition.

(3) Formation of adhesive layer On the release surface of a release sheet (manufactured by Lintec, product name "SP-PET381031") consisting of a polyethylene terephthalate film with a thickness of 38 μm and a silicone-based release agent layer formed on one side , The coating liquid of the adhesive composition obtained in the above step (2) was applied and dried by heating to obtain a laminate in which an adhesive layer having a thickness of 5 μm was formed on the release sheet. .

(4) Preparation of adhesive sheet After subjecting one side of the substrate obtained in step (1) above to corona treatment, the corona-treated surface and the adhesive layer in the laminate obtained in step (3) above are treated. A work processing sheet was obtained by laminating the side surfaces.

(5) Measurement of the weight average molecular weight (Mw) of the (meth)acrylic acid ester copolymer The above-mentioned weight average molecular weight (Mw) of the (meth)acrylic acid ester copolymer is determined by gel permeation chromatography (GPC). It is a polystyrene-equivalent weight-average molecular weight measured (GPC measurement) under the following conditions.
<Measurement conditions>
・ GPC measurement device: HLC-8320 manufactured by Tosoh Corporation
・ GPC column (passed in the following order): TSK gel superH-H manufactured by Tosoh Corporation
TSK gel super HM-H
TSK gel super H2000
・Measurement solvent: tetrahydrofuran ・Measurement temperature: 40°C

[Examples 2 to 14 and Comparative Example 2]
A work processing sheet was produced in the same manner as in Example 1, except that the type and content of the alkylene glycol-based component were changed as shown in Table 1.

[Comparative Example 1]
A work processing sheet was produced in the same manner as in Example 1, except that no alkylene glycol-based component was used.

Details of abbreviations and the like in Table 1 are as follows.
PEG300: Polyethylene glycol (manufactured by Toho Chemical Industry Co., Ltd., product name “PEG300”, number average molecular weight: 300)
PEG1000: Polyethylene glycol (manufactured by Toho Chemical Industry Co., Ltd., product name “PEG1000”, number average molecular weight: 1000)
PTMG250: Polytetramethylene ether glycol (manufactured by Mitsubishi Chemical Corporation, product name "PTMG250", number average molecular weight: 250)
PTMG1000: polytetramethylene ether glycol (manufactured by Mitsubishi Chemical Corporation, product name "PTMG1000", number average molecular weight: 1000)
PTMG3000: polytetramethylene ether glycol (manufactured by Mitsubishi Chemical Corporation, product name "PTMG3000", number average molecular weight: 3000)
PP-200: Polyoxypropylene glycol (manufactured by Sanyo Chemical Industries, Ltd., product name "Sannix PP-200", number average molecular weight: 200)
PP-1000: Polyoxypropylene glycol (manufactured by Sanyo Chemical Industries, Ltd., product name "Sannix PP-1000", number average molecular weight: 1000)
PP-2000: Polyoxypropylene glycol (manufactured by Sanyo Chemical Industries, Ltd., product name "Sannix PP-2000", number average molecular weight: 2000)
PP-4000: Polyoxypropylene glycol (manufactured by Sanyo Chemical Industries, Ltd., product name "Sannix PP-4000", number average molecular weight: 4160)

[Test Example 1] (Measurement of adhesive strength)
The work processing sheets produced in Examples and Comparative Examples were cut into strips having a width of 25 mm. The release sheet is peeled off from the obtained strip-shaped work processing sheet, and the adhesive surface of the exposed adhesive layer is exposed to the mirror surface of the mirror-finished silicon wafer at a temperature of 23 ° C. and a relative humidity of 50%. It was applied using a 2 kg rubber roller under the environment and allowed to stand for 20 minutes to obtain a sample for measurement. The mirror surface of the silicon wafer was a surface (normal surface) that had lost its activity after one month or more of grinding.

For the obtained measurement sample, using a universal tensile tester (manufactured by Orientec, product name “Tensilon UTM-4-100”), the workpiece was processed from the silicon wafer at a peeling speed of 300 mm / min and a peeling angle of 180 °. The sheet was peeled off, and the adhesive strength (mN/25 mm) to the silicon wafer was measured by a 180° peeling method according to JIS Z0237:2009. The adhesive strength thus obtained is shown in Table 1 as the adhesive strength before UV irradiation.

In addition, for the measurement sample obtained in the same manner as above, 20 minutes after attaching to the silicon wafer, in an environment with a temperature of 23 ° C. and a relative humidity of 50%, an ultraviolet irradiation device (manufactured by Lintec, product name "RAD-2000m /12") was used to perform ultraviolet (UV) irradiation (illuminance: 230 mW/cm ² , light amount: 190 mJ/cm ² ). For the measurement sample after the ultraviolet irradiation, the work processing sheet was separated from the silicon wafer in the same manner as described above, and the adhesive force (mN/25 mm) to the silicon wafer was measured. The adhesive strength thus obtained is shown in Table 1 as the adhesive strength after UV irradiation.

[Test Example 2] (Evaluation of dicing)
The release sheets were peeled off from the work processing sheets produced in Examples and Comparative Examples to expose the pressure-sensitive adhesive layer. Then, one side of a 6-inch silicon wafer (thickness: 150 μm) was previously ground using a grinder (manufactured by Disco, product name “DFG8540”). The exposed surface of the pressure-sensitive adhesive layer in was attached.

One hour after the application, using a dicing machine (manufactured by Disco, product name "DFD6362"), the silicon wafer was singulated into chips by performing dicing on the work processing sheet under the following dicing conditions. .
Dicing conditions Chip size: 10 mm x 10 mm
Cutting height: 60 μm
Blade: Product name "ZH05-SD2000-Z1-90 CC"
Blade rotation speed: 35000rpm
Cutting speed: 30mm/sec
Cutting water volume: 1.0 L/min
Cutting water temperature: 20°C

Then, the number of chips that occurred during the dicing process was counted. The number is shown in Table 1. In general, the number of chip jumps occurring during dicing is required to be 40 or less, preferably 5 or less.

[Test Example 3] (Evaluation of pickup)
After the dicing in Test Example 2, the chips obtained were placed on a work processing sheet and stored for 7 days. After that, the surface of the work processing sheet on the substrate side is irradiated with ultraviolet rays (UV) using an ultraviolet irradiation device (manufactured by Lintec, product name “RAD-2000m/12”) (illuminance: 230 mW / cm ² , light amount: 190 mJ/cm ² ) to cure the adhesive layer.

Next, for one chip located near the center of the work processing sheet in plan view, using a pick-up device, at room temperature, the thrust speed was set to 5 mm / sec, the holding time was set to 0.1 msec, and the thrust amount was adjusted. A needle was used to push up the chip by setting it to a predetermined value. Simultaneously with the push-up, an attempt was made to separate the chip from the work processing sheet using a vacuum collet of 8 mm×8 mm. These pushing-up of the tip and separation by the collet were repeated while changing the pushing-up amount stepwise, and the minimum value of the pushing-up amount (μm) when the chip could be picked up three times in succession without causing an abnormality was determined. The minimum value is shown in Table 1 as the minimum push-up amount (μm).

As can be seen from Table 1, the workpiece processing sheets obtained in Examples had a minimum thrust amount of 150 μm or less in the pick-up evaluation, and were found to be able to be picked up satisfactorily without requiring excessive thrust.

The work processing sheet of the present invention can be suitably used for processing a work such as a semiconductor wafer.

Claims (5)

A work processing sheet comprising a substrate and an adhesive layer laminated on one side of the substrate,
The pressure-sensitive adhesive layer is
an acrylic polymer having an active energy ray-curable group introduced into its side chain;
A work characterized by being formed from an adhesive composition containing an alkylene glycol-based component having a number average molecular weight of 200 or more and 3000 or less, which is at least one of polyethylene glycol and polytetramethylene ether glycol. processing sheet. The pressure-sensitive adhesive composition contains the polyethylene glycol as the alkylene glycol-based component,
The content of the polyethylene glycol in the adhesive composition is 0.001 parts by mass or more and 2 parts by mass with respect to 100 parts by mass of the acrylic polymer having an active energy ray-curable group introduced into the side chain. The work processing sheet according to claim 1, characterized by: The pressure-sensitive adhesive composition contains the polytetramethylene ether glycol as the alkylene glycol-based component,
The content of the polytetramethylene ether glycol in the pressure-sensitive adhesive composition is 0.001 parts by mass or more with respect to 100 parts by mass of the acrylic polymer having an active energy ray-curable group introduced into the side chain, 3. The work processing sheet according to claim 1, wherein the content is 10 parts by mass or less. A work processing sheet comprising a substrate and an adhesive layer laminated on one side of the substrate,
The pressure-sensitive adhesive layer is
an acrylic polymer having an active energy ray-curable group introduced into its side chain;
It is formed from a pressure-sensitive adhesive composition containing polypropylene glycol and an alkylene glycol-based component having a number average molecular weight of 200 or more and 3000 or less,
The content of the alkylene glycol-based component in the pressure-sensitive adhesive composition is 0.001 parts by mass or more, 2 A work processing sheet characterized by having a mass part or less. The work processing sheet according to any one of claims 1 to 4, wherein the work processing sheet is used as at least one of a dicing sheet and a pick-up sheet.