JP2023118349A - Workpiece processing sheet - Google Patents

Abstract

To provide a workpiece processing sheet that allows for good pick-up.SOLUTION: A workpiece processing sheet includes a substrate and an adhesive layer laminated on one side of the substrate, the adhesive layer is composed of an active energy ray-curable adhesive formed from an adhesive composition containing an aliphatic epoxy group-containing compound.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 examples of the work processing sheet, Patent Documents 1 to 5 disclose work processing sheets provided with an adhesive layer containing a predetermined component.

In particular, Patent Document 1 discloses a work processing sheet provided with an adhesive layer containing a predetermined amount of polypropylene glycol having a predetermined number average molecular weight (paragraph 0084 of Patent Document 1, etc.). Further, Patent Document 2 discloses a work processing sheet provided with an adhesive layer containing a predetermined polypropylene oxide (Claim 1 of Patent Document 2, etc.). Further, in Patent Document 3, predetermined polyoxypropylene-glyceryl ether (paragraph 0041 of Patent Document 3, etc.), polyoxypropylene-diglyceryl ether (0044, etc. of Patent Document 3) or polyoxypropylene-sorbitol (Patent Document 3) No. 3, 0045, etc.) is disclosed.

Patent No. 4931519 Patent No. 5764518 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, conventional work processing sheets cannot sufficiently meet such pickup requirements.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a work processing sheet that can be picked up satisfactorily.

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 comprises fat Provided is a work processing sheet comprising an active energy ray-curable adhesive formed from an adhesive composition containing a group epoxy group-containing compound (Invention 1).

In the work processing sheet according to the above invention (invention 1), the adhesive layer is composed of an active energy ray-curable adhesive formed from an adhesive composition containing an aliphatic epoxy group-containing compound. As a result, the adhesion of the work processing sheet to the chip moderately decreases when the chip is picked up. As a result, with the work processing sheet, it is possible to easily pick up the chip without requiring excessive pushing up or excessive suction by a vacuum collet.

In the above invention (Invention 1), the adhesive composition comprises, in addition to the aliphatic epoxy group-containing compound, an acrylic polymer (A) having an active energy ray-curable group introduced into a side chain and a side chain contains at least one acrylic polymer (B) into which an active energy ray-curable group has not been introduced, and the content of the aliphatic epoxy group-containing compound in the pressure-sensitive adhesive composition is the acrylic It is preferably 0.005 parts by mass or more and 12 parts by mass or less with respect to 100 parts by mass of the total amount of the polymer (A) and the acrylic polymer (B) (Invention 2).

In the above inventions (inventions 1 and 2), the pressure-sensitive adhesive composition contains an acrylic polymer (A) having an active energy ray-curable group introduced into a side chain and the aliphatic epoxy group-containing compound. is preferred (invention 3).

In the above inventions (inventions 1 to 3), the pressure-sensitive adhesive composition comprises an acrylic polymer (B) in which no active energy ray-curable group is introduced into the side chain, an active energy ray-curable component, and the aliphatic It is preferable to contain an epoxy group-containing compound (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 according to the present invention, it is possible to perform good pickup.

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 obtained 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 As described above, the adhesive layer in the present embodiment is composed of an active energy ray-curable adhesive formed from an adhesive composition containing an aliphatic epoxy group-containing compound. be.

Since the adhesive layer of the work processing sheet according to the present embodiment is composed of the above-described adhesive composition, it is possible to perform good pickup. In particular, since the adhesive constituting the adhesive layer has active energy ray curability, the adhesive strength to the work can be favorably reduced by irradiating the adhesive layer with active energy rays. Furthermore, the use of the above-described aliphatic epoxy group-containing compound moderately reduces the adhesion between the pressure-sensitive adhesive layer and the work. 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 reduction in production efficiency due to pick-up failure.

A preferred aspect of the pressure-sensitive adhesive composition of the present embodiment is a pressure-sensitive adhesive composition containing at least an acrylic polymer (A) having an active energy ray-curable group introduced into its side chain and an aliphatic epoxy group-containing compound. , and a pressure-sensitive adhesive composition containing at least an acrylic polymer (B) in which an active energy ray-curable group is not introduced into the side chain, an active energy ray-curable component, and an aliphatic epoxy group-containing compound. . These components and other components that may be contained in the adhesive composition are described below.

(2-1) Acrylic polymer (A) having active energy ray-curable groups introduced into side chains
The acrylic polymer (A) (hereinafter sometimes referred to as "active energy ray-curable polymer (A)") in which an active energy ray-curable group is introduced into the side chain in the present embodiment is particularly limited. First, for example, it is obtained by reacting an acrylic copolymer (a1) having a functional group-containing monomer unit with an unsaturated group-containing compound (a2) having a functional group that binds to the functional group. is preferred.

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.

Examples of functional group-containing monomers as structural units of the acrylic copolymer (a1) include 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, and the like. in the molecule. Among these, hydroxy group-containing monomers containing a hydroxy group are preferred.

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.

When the acrylic copolymer (a1) contains the functional group-containing monomer (especially the hydroxy group-containing monomer), the mass ratio of the structural portion derived from the functional group-containing monomer in the acrylic copolymer (a1) is It is preferably 5% by mass or more, particularly preferably 10% by mass or more, further 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.

Examples of the aforementioned carboxy group-containing monomers include ethylenically unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid, citraconic acid, and carboxyethyl acrylate. These may be used alone or in combination of two or more.

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

When the acrylic copolymer (a1) in the present embodiment contains a functional group-containing monomer, the functional group-containing monomer is preferably a hydroxy group-containing monomer. It is preferably not a group-containing monomer, an amino group-containing monomer, or a substituted amino group-containing monomer. As a result, the functional groups in the acrylic polymer (A) (and the acrylic polymer (B)) obtained from the acrylic copolymer (a1) react with the epoxy groups of the aliphatic epoxy group-containing compound. is less likely to occur, and the aliphatic epoxy group-containing compound tends to exist in a free state in the pressure-sensitive adhesive composition or the pressure-sensitive adhesive layer. As a result, the aliphatic epoxy group-containing compound is likely to act to adjust the adhesive strength, and as a result, it is easy to achieve excellent pick-up properties.

From such a viewpoint, when the acrylic copolymer (a1) contains at least one of a carboxy group-containing monomer, an amino group-containing monomer and a substituted amino group-containing monomer as the functional group-containing monomer, the acrylic copolymer The mass ratio of the structural portion derived from these monomers in (a1) is preferably 20% by mass or less, particularly preferably 10% by mass or less, and further 0% by mass (i.e., not contain) is preferable. In addition, the lower limit of the ratio may be, for example, 0.01% by mass or more, particularly 0.1% by mass or more, and further may be 0.2% by mass or more.

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 or a carboxy group.

Further, the unsaturated group-containing compound (a2) has at least one, preferably 1 to 6, more preferably 1 to 4 carbon-carbon double bonds polymerizable with active energy rays per molecule. include. 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 an active 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 pressure-sensitive adhesive composition is 0.5 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) Acrylic polymer (B) having no active energy ray-curable group introduced into the side chain
As the acrylic polymer (B) having no active energy ray-curable group introduced into the side chain, for example, the same component as the acrylic copolymer (a1) described above can be used.

In addition, when the acrylic copolymer (a1) used as the acrylic polymer (B) contains the above-described functional group-containing monomer (especially a hydroxy group-containing monomer), the acrylic copolymer (a1) is preferably 0.1% by mass or more, particularly preferably 1% by mass or more, further preferably 3% by mass or more. The above proportion is preferably 30% by mass or less, particularly preferably 25% by mass or less, and further preferably 20% by mass or less. When the ratio of the structural portion derived from the functional group-containing monomer is within the above range, the desired adhesive strength can be easily exhibited.

Further, when the acrylic copolymer (a1) contains at least one of a carboxy group-containing monomer, an amino group-containing monomer and a substituted amino group-containing monomer as the functional group-containing monomer, in the acrylic copolymer (a1) The mass ratio of the structural portion derived from these monomers in is preferably 30% by mass or less, particularly preferably 20% by mass or less, and further 0% by mass (i.e., not containing) is preferred. In addition, the lower limit of the ratio may be, for example, 0.1% by mass or more, particularly 1% by mass or more, and further may be 3% by mass or more.

Further, when the acrylic copolymer (a1) used as the acrylic polymer (B) contains the (meth)acrylic acid ester monomer described above, the (meth) in the acrylic copolymer (a1) The proportion of the structural portion derived from the acrylate monomer is preferably 80% by mass or more, particularly preferably 85% by mass or more, further preferably 90% by mass or more. The above proportion is preferably 99.9% by mass or less, particularly preferably 99% by mass or less, and more preferably 97% 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.

(2-3) Active Energy Ray-Curable Component The active energy ray-curable component in the present embodiment is not particularly limited as long as it is a component having active energy ray-curable properties. In addition, in this specification, the active energy ray-curable component is different from the acrylic polymer (A) in which the active energy ray-curable group is introduced into the side chain.

When the pressure-sensitive adhesive composition in the present embodiment contains an acrylic polymer (B) in which no active energy ray-curable group is introduced into the side chain, the pressure-sensitive adhesive composition further contains an active energy ray-curable component. By doing so, the pressure-sensitive adhesive layer in the present embodiment exhibits good active energy ray curability. In addition, even when the adhesive composition in the present embodiment contains an acrylic polymer (A) in which an active energy ray-curable group is introduced into the side chain, the adhesive composition is active energy ray-curable. may contain sexual components.

Preferred examples of active energy ray-curable components include active energy ray-curable monomers and/or oligomers. Specific examples include monofunctional acrylates such as cyclohexyl (meth) acrylate and isobornyl (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) ) acrylate, dipentaerythritol hexa(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, polyethylene glycol di(meth)acrylate, dimethyloltricyclodecanedi Polyfunctional acrylates such as (meth)acrylates, polyester oligo(meth)acrylates, polyurethane oligo(meth)acrylates, and the like can be mentioned. These may be used individually by 1 type, and may be used in combination of 2 or more type.

When the adhesive composition in the present embodiment contains an active energy ray-curable component together with the acrylic polymer (B) in which an active energy ray-curable group is not introduced into the side chain, the active energy in the adhesive composition The content of the ray-curing component is preferably more than 30 parts by mass, particularly preferably 60 parts by mass or more, relative to 100 parts by mass of the acrylic polymer (B). Moreover, the content is preferably 250 parts by mass or less, particularly preferably 200 parts by mass or less, relative to 100 parts by mass of the acrylic polymer (B).

(2-4) Aliphatic epoxy group-containing compound The aliphatic epoxy group-containing compound in the present embodiment has a structure in which an epoxy group is introduced into an aliphatic compound or a compound having an aliphatic compound as a basic skeleton. is not particularly limited as long as it has Epoxy group-containing compounds generally include aromatic compounds such as bisphenol-type epoxy group-containing compounds. However, the use of the aliphatic epoxy group-containing compound in the work processing sheet according to the present invention makes it easier to keep the chlorine content in the pressure-sensitive adhesive layer low. This is because the aliphatic epoxy group-containing compound can be produced in a lower amount of raw materials containing a chlorine component than the aromatic epoxy group-containing compound. Since the work processing sheet according to the present invention contains less chlorine components in the pressure-sensitive adhesive layer, it can sufficiently respond to applications requiring chlorine-free.

In the pressure-sensitive adhesive composition and the pressure-sensitive adhesive layer of the present embodiment, the aliphatic epoxy group-containing compound is in a free state, that is, combined with other components such as the acrylic polymer (A) and the acrylic polymer (B). It is preferred that it exists in a state where it is not This makes it easier for the aliphatic epoxy group-containing compound to exert its action, making it easier to moderately reduce the adhesion between the adhesive layer and the work, and as a result, it tends to have better pick-up properties. Become.

The number of epoxy groups in one molecule of the aliphatic epoxy group-containing compound in the present embodiment is preferably 1 or more, particularly preferably 2 or more. Also, the number of epoxy groups is preferably 5 or less, particularly preferably 4 or less. Aliphatic epoxy group-containing compounds having the number of epoxy groups within these ranges can be produced using a low amount of raw materials containing chlorine components. As a result, it becomes easy to suppress contamination of the chlorine component in the pressure-sensitive adhesive composition and the pressure-sensitive adhesive layer in which the aliphatic epoxy group-containing compound is used.

The epoxy equivalent of the aliphatic epoxy group-containing compound in the present embodiment is preferably 100 g/eq or more, particularly preferably 150 g/eq or more, further preferably 200 g/eq or more. Moreover, the epoxy equivalent is preferably 1000 g/eq or less, particularly preferably 900 g/eq or less, and further preferably 800 g/eq or less. When the epoxy equivalent of the aliphatic epoxy group-containing compound is within the above range, the adhesion between the pressure-sensitive adhesive layer and the work tends to be moderately reduced, and as a result, it tends to have better pick-up properties. .

The aliphatic epoxy group-containing compound in this embodiment may have a functional group other than the epoxy group. Examples of such functional groups include hydroxy groups, carboxy groups, amino groups, vinyl groups, alkoxysilyl groups, and the like. Generally, blade dicing of semiconductor wafers and the like is performed while supplying cutting water. In this case, the lower the polarity of the adhesive layer of the work processing sheet, the easier it is to suppress the entry of water into the interface between the adhesive layer and the adherend, and as a result, the resulting semiconductor chip is suppressed from chip flying. becomes easier. From this point of view, the aliphatic epoxy group-containing compound in the present embodiment preferably does not have functional groups such as relatively highly hydrophilic hydroxyl groups, carboxy groups, and amino groups.

The molecular weight of the aliphatic epoxy group-containing compound in the present embodiment is preferably 100 or more, particularly preferably 200 or more, further preferably 300 or more. Further, the molecular weight is preferably 2000 or less, particularly preferably 1800 or less, further preferably 1600 or less. When the molecular weight of the aliphatic epoxy group-containing compound is within these ranges, the adhesion between the pressure-sensitive adhesive layer and the work tends to moderately decrease, and as a result, it tends to have better pick-up properties. .

Preferred specific examples of the aliphatic epoxy group-containing compound in the present embodiment include ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, polytetramethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, and neopentyl glycol diglycidyl ether. , 1,6-hexanediol diglycidyl ether, sorbitol polyglycidyl ether, glycerol polyglycidyl ether, diglycerol polyglycidyl ether, polyglycerol polyglycidyl ether, trimethylolpropane polyglycidyl ether, pentaerythritol polyglycidyl ether and the like. Among these, it is preferable to use one selected from polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, and sorbitol polyglycidyl ether from the viewpoint of easily achieving excellent pick-up properties.

The content of the aliphatic epoxy group-containing compound in the adhesive composition in the present embodiment is the total amount of the acrylic polymer (A) and the acrylic polymer (B) (acrylic polymer (A) and acrylic When only one of the polymer (B) is contained, it is preferably 0.005 parts by mass or more, particularly 0.1 parts by mass, relative to 100 parts by mass of the content of the contained component) It is preferably 1.0 parts by mass or more, more preferably 1.0 parts by mass or more. When the content of the aliphatic epoxy group-containing compound is 0.005 parts by mass or more, the adhesion between the pressure-sensitive adhesive layer and the work becomes appropriate, and excellent pick-up property can be easily realized. In addition, the content of the aliphatic epoxy group-containing compound is preferably 12 parts by mass or less with respect to 100 parts by mass of the total amount of the acrylic polymer (A) and the acrylic polymer (B). It is more preferably not more than 5 parts by mass, particularly preferably not more than 5 parts by mass, further preferably not more than 2 parts by mass. When the content of the aliphatic epoxy group-containing compound is 12 parts by mass or less, it becomes easy to suppress chip flying during dicing.

(2-5) 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 acrylic polymer (A) or the acrylic polymer (B) can be cross-linked in the pressure-sensitive adhesive layer to form a good three-dimensional network structure. Become. 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 the total amount of the acrylic polymer (A) and the acrylic polymer (B) (acrylic When only one of the polymer (A) and the acrylic polymer (B) is contained, it is preferably 0.1 parts by mass or more with respect to 100 parts by mass of the content of the contained component) In particular, it is preferably at least 0.5 parts by mass, more preferably at least 3 parts 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.

(2-6) 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, 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]phenyl}-2-methyl-propan-1-one, benzyl diphenyl sulfide, tetramethylthiuram monosulfide, azobisisobutyronitrile, benzyl, dibenzyl, diacetyl, β-chloroanthraquinone, (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, etc. 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 adhesive composition in the present embodiment contains a photopolymerization initiator, the content of the photopolymerization initiator in the adhesive composition is the total of the acrylic polymer (A) and the acrylic polymer (B) Amount (when only one of the acrylic polymer (A) and the acrylic polymer (B) is contained, the content of the contained component) 0.1 parts by mass or more per 100 parts by mass It is preferably at least 1 part by mass. 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

(2-7) 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 the aforementioned effects of the work processing sheet according to the present embodiment are not impaired. , tackifiers, antioxidants, light stabilizers, softeners, fillers, refractive index modifiers and the like can be added.

(2-8) Method for preparing an adhesive composition The adhesive composition in the present embodiment is obtained by producing an acrylic polymer (A) or an acrylic polymer (B), and obtaining an acrylic polymer (A ) or by mixing an acrylic polymer (B), an aliphatic epoxy group-containing compound, and optionally an active energy ray-curable component, a cross-linking agent, a photopolymerization initiator, and an additive. can do. 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, the pressure-sensitive adhesive composition is diluted to a concentration of 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 pressure-sensitive adhesive composition has a viscosity that allows coating. In this case, the pressure-sensitive adhesive composition becomes a coating liquid in which the polymerization solvent for the acrylic copolymer (a1) is used as the diluting solvent.

(2-9) 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 fly can be 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 50 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 adhesive layer is composed of an active energy ray-curable adhesive formed from an adhesive composition containing an aliphatic epoxy group-containing compound. After the energy beam irradiation, it becomes easy to achieve the adhesive strength as described above. 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 favorably pick up chips obtained by dividing a work such as a semiconductor wafer into individual pieces. 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. 0.13 parts by mass of dibutyltin dilaurate (DBTDL) was added to 100 parts by mass of the total amount of the above monomers. After that, reaction was carried out at 50° C. for 24 hours to obtain an acrylic polymer (A) in which side chains were introduced with active energy ray-curable groups. When the weight average molecular weight of the acrylic polymer (A) was measured by the method described later, it was 500,000.

100 parts by mass of the obtained acrylic polymer (A) (in terms of solid content, hereinafter the same), and 1.07 parts by 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 polyethylene glycol diglycidyl ether as an epoxy group-containing compound (aliphatic epoxy group-containing compound, Nagase ChemteX Corporation, product name "Denacol EX-830", Number of epoxy groups: 2, epoxy equivalent: 268 g / eq, total chlorine content: 0.3%) 0.07 parts by mass were mixed in a solvent, and a coating liquid of the adhesive composition (solid content concentration 28% by mass) was prepared. Obtained.

(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 8 and Comparative Examples 2 to 3]
A work processing sheet was produced in the same manner as in Example 1, except that the type and content of the epoxy group-containing compound 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 epoxy group-containing compound was used.

Details of abbreviations and the like in Table 1 are as follows.
[Epoxy group-containing compound]
Denacol EX-830: polyethylene glycol diglycidyl ether (aliphatic epoxy group-containing compound, manufactured by Nagase ChemteX Corporation, product name "Denacol EX-830", number of epoxy groups: 2, epoxy equivalent: 268 g / eq, total chlorine content: 0.3%)
Denacol EX-931: polypropylene glycol diglycidyl ether (aliphatic epoxy group-containing compound, manufactured by Nagase ChemteX Corporation, product name "Denacol EX-931", number of epoxy groups: 2, epoxy equivalent: 471 g / eq, total chlorine content: 3.9%)
Denacol EX-991L: A compound having glycidyl ether groups at both ends of an acyclic aliphatic compound (aliphatic epoxy group-containing compound, manufactured by Nagase ChemteX Corporation, product name "Denacol EX-991L", number of epoxy groups: 2 , epoxy equivalent: 450 g / eq, total chlorine content: 0.1%)
Denacol EX-614B: sorbitol polyglycidyl ether (aliphatic epoxy group-containing compound, manufactured by Nagase ChemteX Corporation, product name "Denacol EX-614B", number of epoxy groups: 4, epoxy equivalent: 173 g/eq, total chlorine content: 10 .1%)
Epiclone EXA-4850-150: A compound having glycidyl ether groups at both ends of a bisphenol-containing hydrocarbon compound (bisphenol type epoxy group-containing compound, manufactured by DIC, product name "Epiclone EXA-4850-15", number of epoxy groups : 2, epoxy equivalent: 450 g / eq)

[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: 350 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.

Three hours after the application, the silicon wafer was singulated into chips by performing dicing on the work processing sheet under the following dicing conditions using a dicing machine (manufactured by Disco, product name "DFD6362"). .
Dicing conditions Chip size: 3mm x 3mm
Cutting height: 60 μm
Blade: Product name "ZH05-SD2000-Z1-90 ED"
Blade rotation speed: 35000rpm
Cutting speed: 60mm/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)
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.

Seven days after the application, the silicon wafer was singulated into chips by performing dicing on the work processing sheet under the following dicing conditions using a dicing machine (manufactured by Disco, product name "DFD6362").
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: 60mm/sec
Cutting water volume: 1.0 L/min
Cutting water temperature: 20°C

Subsequently, 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 , amount of light: 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 with a vacuum collet of 10 mm×10 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. In addition, in the work processing sheets obtained in the examples, the number of chips flying during dicing could be suppressed to a low level.

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,
A work processing sheet, wherein the pressure-sensitive adhesive layer is composed of an active energy ray-curable pressure-sensitive adhesive formed from a pressure-sensitive adhesive composition containing an aliphatic epoxy group-containing compound. The pressure-sensitive adhesive composition includes, in addition to the aliphatic epoxy group-containing compound, an acrylic polymer (A) in which an active energy ray-curable group is introduced into the side chain and an active energy ray-curable group in the side chain. containing at least one acrylic polymer (B) that has not been introduced,
The content of the aliphatic epoxy group-containing compound in the adhesive composition is 0.005 with respect to 100 parts by mass of the total amount of the acrylic polymer (A) and the acrylic polymer (B). 2. The work processing sheet according to claim 1, wherein the content is 12 parts by mass or more and 12 parts by mass or less. 3. The adhesive composition according to claim 1 or 2, characterized in that it contains an acrylic polymer (A) in which an active energy ray-curable group is introduced into a side chain and the aliphatic epoxy group-containing compound. A work processing sheet as described. The pressure-sensitive adhesive composition is characterized by containing an acrylic polymer (B) in which no active energy ray-curable group is introduced into the side chain, an active energy ray-curable component, and the aliphatic epoxy group-containing compound. The work processing sheet according to any one of claims 1 to 3. 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.