JP2020158656A - Tacky adhesive sheet for workpiece processing - Google Patents

Abstract

To provide a tacky adhesive sheet for workpiece processing, having plating resistance and exerting a favorable workpiece separability even in a long-term storage under a fluorescent lamp.SOLUTION: A tacky adhesive sheet for workpiece processing comprises a substrate and a tacky adhesive layer laminated on a single face side of the substrate. The adhesive layer consists of an active energy ray-curable tacky adhesive. When preparing the tacky adhesive sheet after a fluorescent lamp treatment including irradiating a face of the side opposite to the adhesive layer with a visible light of light flux 2,100 lumen for 14 days using the fluorescent lamp disposed separately by 100 cm from the above face as a light source, the adhesive force of the sheet to a silicon wafer measured in a hot water at 90°C is 1,600 mN/25 mm or more.SELECTED DRAWING: None

Description

The present invention relates to an adhesive sheet for processing a work, which can be suitably used for processing a work such as a semiconductor wafer.

Semiconductor wafers such as silicon and gallium arsenide and various packages are manufactured in a large-diameter state, cut (diced) into small element pieces (semiconductor chips), peeled (picked up), and then mounted, which is the next process. Moved to. At this time, the work such as a semiconductor wafer is subjected to processing such as back grinding, dicing, cleaning, drying, expanding, picking up, and mounting while being attached to a work adhesive sheet provided with a base material and an adhesive layer. Will be done.

Further, in the case of producing a semiconductor wafer with a gold film for a power device, the semiconductor wafer fixed on the adhesive sheet for processing a work is usually immersed in a plating solution. In this case, the adhesive sheet for workpiece processing is exposed to the plating solution together with the semiconductor wafer. Therefore, even if the adhesive sheet for workpiece processing is exposed to the plating solution, its function can be maintained. It is required to have excellent plating resistance. Specifically, it is required to have a performance capable of suppressing the infiltration of the plating solution into the interface between the work adhesive sheet for processing the work and the work and suppressing the generation of air bubbles at the interface. Patent Document 1 discloses an example of an adhesive sheet for work processing having such plating resistance.

Japanese Unexamined Patent Publication No. 2016-34993

By the way, some pressure-sensitive adhesive sheets for work processing have a pressure-sensitive adhesive layer formed by using a pressure-sensitive adhesive having active energy ray curability. In such a pressure-sensitive adhesive sheet for work processing, the pressure-sensitive adhesive layer can be cured by irradiating the pressure-sensitive adhesive layer with active energy rays after the processing is completed. As a result, the adhesive force to the work is satisfactorily lowered, and the work after the processing is completed can be easily separated from the work adhesive sheet for processing.

However, the pressure-sensitive adhesive sheet for work processing provided with the pressure-sensitive adhesive layer composed of the above-mentioned active energy ray-curable pressure-sensitive adhesive is used for irradiation with active energy rays when stored for a long period of time under a fluorescent lamp before its use. There is a problem that it is difficult to separate the workpieces because the resulting decrease in adhesive strength cannot be sufficiently caused.

The present invention has been made in view of such an actual situation, and is used for workpiece processing which has plating resistance and can exhibit good workpiece separability even when stored for a long period of time under a fluorescent lamp. It is an object of the present invention to provide an adhesive sheet.

In order to achieve the above object, first, the present invention is a work pressure-sensitive adhesive sheet including a base material and a pressure-sensitive adhesive layer laminated on one side of the base material, and the pressure-sensitive adhesive layer is A fluorescent lamp composed of an active energy ray-curable pressure-sensitive adhesive and arranged 100 cm away from the surface of the base material opposite to the pressure-sensitive adhesive layer is used as a light source, and visible light having a luminous flux of 2100 lumens is emitted from the surface. The adhesive sheet for workpiece processing after being subjected to fluorescent lamp treatment by irradiating for 14 days is characterized in that the adhesive force to the silicon wafer measured in warm water at 90 ° C. is 1600 mN / 25 mm or more. An adhesive sheet is provided (Invention 1).

The adhesive sheet for workpiece processing according to the above invention (Invention 1) exhibits excellent plating resistance when the adhesive force measured in warm water after the above-mentioned fluorescent lamp treatment is within the above range. In addition, good separability can be exhibited for the work even when it is stored for a long period of time under a fluorescent lamp.

In the above invention (Invention 1), with respect to the adhesive sheet for work processing which has not been subjected to the fluorescent lamp treatment, the adhesive force to the silicon wafer measured in warm water at 90 ° C. is 3000 mN / 25 mm or more and 30,000 mN / 25 mm or less. It is preferable that there is (Invention 2).

In the above invention (Invention 2), for the work processing adhesive sheet that has not been subjected to the fluorescent lamp treatment, the work processing that has been subjected to the fluorescent lamp treatment with respect to the adhesive force to the silicon wafer measured in warm water at 90 ° C. Regarding the adhesive sheet, the ratio of the adhesive force to the silicon wafer measured in warm water at 90 ° C. is preferably 35% or more (Invention 3).

In the above inventions (Inventions 1 to 3), the adhesive sheet for work processing subjected to the fluorescent lamp treatment with respect to the adhesive force to the silicon wafer after irradiation with active energy rays in the adhesive sheet for work processing not subjected to the fluorescent lamp treatment. The ratio of the adhesive force to the silicon wafer after irradiation with active energy rays is preferably 90% or more and 140% or less (Invention 4).

In the above inventions (Inventions 1 to 4), the adhesive force for silicon wafer after irradiation with active energy rays of the adhesive sheet for processing a work subjected to the fluorescent lamp treatment is 50 mN / 25 mm or more and 320 mN / 25 mm or less. Preferred (Invention 5).

In the above inventions (Inventions 1 to 5), the active energy ray-curable pressure-sensitive adhesive contains an acrylic polymer having an active energy ray-curable group introduced into a side chain, a cross-linking agent, and a photopolymerization initiator. It is preferably formed from the composition (Invention 6).

In the above invention (Invention 6), the photopolymerization initiator is preferably an oligomer-type photopolymerization initiator (Invention 7).

In the above inventions (Inventions 6 and 7), the content of the photopolymerization initiator in the adhesive composition is 100 parts by mass of the acrylic polymer having an active energy ray-curable group introduced into the side chain. It is preferable that the amount is 0.05 parts by mass or more and less than 3.0 parts by mass (Invention 8).

In the above inventions (Inventions 6 to 8), the cross-linking agent is preferably a metal chelate compound (Invention 9).

In the above inventions (Inventions 6 to 9), the acrylic polymer does not contain a monomer having a cyano group as a monomer unit constituting the polymer, or 0.2% by mass of a monomer having a cyano group. It is preferably included below (Invention 10).

The adhesive sheet for processing a work according to the present invention has plating resistance and can exhibit good work separability even when stored for a long period of time under a fluorescent lamp.

Hereinafter, embodiments of the present invention will be described.
The pressure-sensitive adhesive sheet for processing a work according to an embodiment of the present invention includes a base material and a pressure-sensitive adhesive layer laminated on one side of the base material. The pressure-sensitive adhesive layer in the present embodiment is made of an active energy ray-curable pressure-sensitive adhesive.

1. 1. Physical Properties of Adhesive Sheet for Work Processing In the adhesive sheet for work processing according to the present embodiment, a fluorescent lamp arranged 100 cm away from the surface of the base material opposite to the adhesive layer is used as a light source with respect to the above surface. The adhesive force for workpiece processing after being subjected to a fluorescent lamp treatment of irradiating visible light with a luminous flux of 2100 lumens for 14 days has an adhesive force of 1600 mN / 25 mm or more on a silicon wafer measured in warm water at 90 ° C.

Here, the details of the fluorescent lamp treatment and the details of the method for measuring the adhesive strength are as described in the test examples described later. Further, the adhesive force is the adhesive force measured in a state where the pressure-sensitive adhesive sheet for processing a work is not irradiated with active energy rays. Similarly, in the present specification, the adhesive strength without particular reference to the activation energy ray irradiation refers to the adhesive strength measured in a state where the adhesive sheet for workpiece processing is not irradiated with the active energy ray. ..

If the adhesive strength is less than 1600 mN / 25 mm, the plating resistance of the adhesive sheet for workpiece processing becomes insufficient, and when immersed in the plating solution, the surface of the adhesive layer opposite to the base material (hereinafter, "adhesive surface"). In some cases, the plating solution infiltrates and bubbles are generated at the interface between the work and the work. Further, when the adhesive strength is less than 1600 mN / 25 mm, when the adhesive sheet for workpiece processing is stored for a long period of time under a fluorescent lamp, the adhesive strength is sufficiently lowered even if it is subsequently irradiated with active energy rays. Will not be possible. As a result, the separability of the work becomes insufficient, and problems such as adhesive residue and breakage of the work occur. From the viewpoint of making it easier to avoid these problems, the adhesive strength is preferably 2500 mN / 25 mm or more, and particularly preferably 5000 mN / 25 mm or more.

On the other hand, the adhesive strength is preferably 20000 mN / 25 mm or less. When the adhesive strength is 20000 mN / 25 mm or less, it becomes easy to suppress an excessive increase in the adhesive strength of the adhesive sheet for workpiece processing, and it is easy to adjust the adhesive strength after the active energy ray to an appropriately low value. It becomes. As a result, the separability of the work becomes better, and it becomes easy to effectively suppress adhesive residue and breakage of the work. From this point of view, the adhesive strength is particularly preferably 15,000 mN / 25 mm or less, and further preferably 10000 mN / 25 mm or less.

In the work-processing adhesive sheet according to the present embodiment, the work-processing adhesive sheet that has not been subjected to the fluorescent lamp treatment described above has an adhesive strength to a silicon wafer measured in warm water at 90 ° C. of 3000 mN / 25 mm or more. It is preferably 4000 mN / 25 mm or more, and further preferably 5000 mN / 25 mm or more. The adhesive strength is preferably 30,000 mN / 25 mm or less, particularly preferably 25,000 mN / 25 mm or less, and further preferably 20,000 mN / 25 mm or less. When the adhesive strength is within these ranges, it is easy to adjust the adhesive strength to the silicon wafer measured in warm water at 90 ° C. for the adhesive sheet for workpiece processing after the fluorescent lamp treatment within the above range. It becomes a thing. The details of the method for measuring the adhesive force to the silicon wafer measured in warm water at 90 ° C. for the adhesive sheet for workpiece processing which has not been subjected to the fluorescent lamp treatment are as described in the test examples described later.

In the work-processing adhesive sheet according to the present embodiment, the work-processing adhesive sheet that has not been subjected to fluorescent lamp treatment is subjected to fluorescent lamp treatment against the adhesive force to the silicon wafer measured in warm water at 90 ° C. Regarding the adhesive sheet for processing, the ratio of the adhesive force to the silicon wafer measured in warm water at 90 ° C. is preferably 35% or more, particularly preferably 45% or more, and further 70% or more. It is preferable to have. When the above ratio is 35% or more, the adhesive sheet for workpiece processing can easily maintain the adhesive strength even when stored under a fluorescent lamp for a long period of time, and when irradiated with active energy rays. In addition, the adhesive strength can be satisfactorily reduced, and excellent separability can be easily exhibited. The upper limit of the above ratio is not particularly limited.

In the work-processing adhesive sheet according to the present embodiment, the work-processing adhesive sheet that has been subjected to fluorescent lamp treatment against the adhesive force to the silicon wafer after irradiation with active energy rays in the work-processing adhesive sheet that has not been subjected to fluorescent lamp treatment. The ratio of the adhesive force to the silicon wafer after irradiation with active energy rays is preferably 140% or less, and particularly preferably 120% or less. When the above ratio is 140% or less, even when stored under a fluorescent lamp, the adhesive strength is likely to be satisfactorily lowered when irradiated with active energy rays, thereby providing excellent separability. It will be easy to demonstrate. The upper limit of the above ratio is not particularly limited, and is preferably 90% or more, and particularly preferably 100% or more. Further, the adhesive force against the silicon wafer after irradiation with the active energy ray in the adhesive sheet for work processing not subjected to the fluorescent lamp treatment, and the silicon wafer after the irradiation with the active energy ray in the adhesive sheet for work processing subjected to the fluorescent lamp treatment. The adhesive strength to the light is as described in the test examples described later.

In the work-processing adhesive sheet according to the present embodiment, the adhesive force of the work-processing adhesive sheet treated with a fluorescent lamp to the silicon wafer after irradiation with active energy rays is preferably 320 mN / 25 mm or less, particularly 250 mN. It is preferably / 25 mm or less, and more preferably 220 mN / 25 mm or less. When the adhesive strength is 320 mN / 25 mm or less, even when the product is stored under a fluorescent lamp for a long period of time, the adhesive strength can be easily reduced when irradiated with active energy rays, which is excellent. It becomes easy to exhibit the separability. The lower limit of the adhesive force is not particularly limited, and is preferably 50 mN / 25 mm or more, for example.

In the work-processing adhesive sheet according to the present embodiment, it is preferable that the work-processing adhesive sheet not subjected to the fluorescent lamp treatment has an adhesive force of 320 mN / 25 mm or less on the silicon wafer after irradiation with active energy rays. When the adhesive strength is 320 mN / 25 mm or less, the adhesive strength is likely to be satisfactorily lowered when irradiated with active energy rays, and thus excellent separability is easily exhibited. The lower limit of the adhesive force is not particularly limited, and is preferably 50 mN / 25 mm or more, for example.

2. 2. Components of Adhesive Sheet for Work Processing (1) Base Material The base material in the present embodiment is not limited as long as it exhibits a desired function when the adhesive sheet for work processing is used, but it has plating resistance. It is preferable to have one. In particular, the base material is preferably a resin film whose main material is a resin-based material. Specific examples thereof include polyolefin films such as polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, ethylene-norbornene copolymer film and norbornene resin film; polyethylene terephthalate film, polybutylene terephthalate film and polyethylene. Polyester-based film such as naphthalate; ethylene-vinyl acetate copolymer film; ethylene- (meth) acrylic acid copolymer film, ethylene- (meth) methyl acrylate copolymer film, other ethylene- (meth) acrylic Ethylene-based copolymer films such as acid ester copolymer films; polyvinyl chloride-based 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; fluororesin film and the like can be mentioned. Further, modified films such as these crosslinked films and ionomer films are also used. Further, the base material may be a laminated film in which a plurality of the above-mentioned films are laminated. In this laminated film, the materials constituting each layer may be the same type or different types. In addition, "(meth) acrylic acid" in this specification means both acrylic acid and methacrylic acid. The same applies to other similar terms.

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

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

The thickness of the base material can be appropriately set according to the method in which the adhesive sheet for processing the work is used, and is preferably 50 μm or more, particularly preferably 60 μm or more. The thickness of the base material is preferably 300 μm or less, and particularly preferably 100 μm or less.

(2) Adhesive layer The adhesive constituting the adhesive layer in the present embodiment is an active energy ray-curable adhesive and can exhibit sufficient adhesive force against the work for processing the work. As long as it is not particularly limited.

Since the pressure-sensitive adhesive layer in the present embodiment is composed of an active energy ray-curable pressure-sensitive adhesive, the pressure-sensitive adhesive layer is cured by irradiation with active energy rays, and the adhesive force of the pressure-sensitive adhesive sheet for workpiece processing on the adherend. Can be reduced. This makes it possible to easily separate the work after processing from the adhesive sheet for processing the work.

The active energy ray-curable pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer may be mainly composed of a polymer having active energy ray-curable property, or an active energy ray-curable polymer (active energy ray-curable polymer). The polymer may be mainly composed of a mixture of a monomer having at least one active energy ray-curable group and / or an oligomer.

First, a case where the active energy ray-curable pressure-sensitive adhesive contains a polymer having active energy ray curability as a main component will be described below.

The active energy ray-curable polymer is a (meth) acrylic acid ester (co) polymer (A) in which a functional group (active energy ray-curable group) having an active energy ray-curable group is introduced into the side chain. It may be referred to as "active energy ray-curable polymer (A)"). This active energy ray-curable polymer (A) reacts an acrylic polymer (a1) having a functional group-containing monomer unit with an unsaturated group-containing compound (a2) having a functional group bonded to the functional group. It is preferable that the compound is obtained by allowing the mixture to be obtained.

As the functional group-containing monomer described above, a monomer having a polymerizable double bond and a functional group such as a hydroxy group, a carboxy group, an amino group, an amide group, a benzyl group and a glycidyl group in the molecule is preferable. Of these, it is preferable to use a hydroxy group-containing monomer (hydroxy group-containing monomer) as the functional group.

Examples of the hydroxy group-containing monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, and 2-hydroxybutyl (meth) acrylate. Examples thereof include 3-hydroxybutyl (meth) acrylate and 4-hydroxybutyl (meth) acrylate, and among these, 2-hydroxyethyl acrylate is preferably used. These may be used alone or in combination of two or more.

Examples of the carboxy group-containing monomer include 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. Among these, it is preferable to use acrylic acid.

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

The acrylic polymer (a1) preferably contains the structural unit derived from the functional group-containing monomer in an amount of 5% by mass or more, particularly preferably 7% by mass or more, and further contains 10% by mass or more. Is preferable. Further, the acrylic polymer (a1) preferably contains the structural unit derived from the functional group-containing monomer in an amount of 35% by mass or less, particularly preferably 30% by mass or less, and further, 20% by mass. It is preferably contained in% or less. When the acrylic polymer (a1) contains the functional group-containing monomer in the above range, the desired active energy ray-curable polymer (A) can be easily formed.

From the viewpoint that the acrylic polymer (a1) can easily form a pressure-sensitive adhesive having desired performance, it is also preferable that the acrylic polymer (a1) contains a (meth) acrylic acid alkyl ester as a monomer unit constituting the acrylic polymer (a1). .. As the (meth) acrylic acid alkyl ester, those having an alkyl group having 1 to 18 carbon atoms are preferable, and those having 1 to 4 carbon atoms are particularly preferable.

Specific examples of the above (meth) acrylic acid alkyl ester include methyl (meth) acrylic acid, ethyl (meth) acrylic acid, propyl (meth) acrylic acid, n-butyl (meth) acrylic acid, and n (meth) acrylic acid. -Pentyl, n-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, n-decyl (meth) acrylate, lauryl (meth) acrylate, myristyl (meth) acrylate , (Meta) palmityl acrylate, stearyl (meth) acrylate and the like. These may be used alone or in combination of two or more. Among the above-mentioned (meth) acrylic acid alkyl esters, it is preferable to use at least one of methyl (meth) acrylate and n-butyl (meth) acrylic acid, and in particular, at least methyl methacrylate and n-butyl acrylate. It is preferable to use one type.

The acrylic polymer (a1) preferably contains the structural unit derived from the (meth) acrylic acid alkyl ester in an amount of 50% by mass or more, particularly preferably 60% by mass or more, and further 70% by mass. It is preferable to contain the above. Further, the acrylic polymer (a1) preferably contains the structural unit derived from the (meth) acrylic acid alkyl ester in an amount of 98% by mass or less, particularly preferably 95% by mass or less, and further. Is preferably contained in an amount of 90% by mass or less. When the acrylic polymer (a1) contains the (meth) acrylic acid alkyl ester in the above range, it becomes easy to form a pressure-sensitive adhesive having desired performance.

The acrylic polymer (a1) may be a copolymer of the above-mentioned functional group-containing monomer and (meth) acrylic acid alkyl ester and other monomers.

Examples of the other monomers include alkoxyalkyl group-containing (meth) acrylics such as methoxymethyl (meth) acrylate, methoxyethyl (meth) acrylate, ethoxymethyl (meth) acrylate, and ethoxyethyl (meth) acrylate. Acid ester; (meth) acrylic acid ester having an aliphatic ring such as cyclohexyl (meth) acrylate; (meth) acrylic acid ester having an aromatic ring such as phenyl (meth) acrylate; N- (meth) acryloylmorpholin , N-vinyl-2-pyrrolidone, N- (meth) acryloylpyrrolidone and other monomers having a nitrogen-containing heterocycle; (meth) acrylamide, N, N-dimethyl (meth) acrylamide and other non-crosslinkable acrylamides; (meth) ) (Meta) acrylic acid ester having a non-crosslinkable tertiary amino group such as N, N-dimethylaminoethyl acrylate, N, N-dimethylaminopropyl (meth) acrylate; vinyl acetate; styrene and the like. ..

Further, the acrylic polymer (a1) is easy to exhibit better separability to the work after being stored for a long period of time under a fluorescent lamp, and is easy to reduce the environmental load. It is preferable that the constituent monomer unit does not contain a monomer having a cyano group such as allylonitrile. Further, even when a monomer having a cyano group is contained, the content thereof is preferably 0.2% by mass or less.

The polymerization mode of the acrylic polymer (a1) may be a random copolymer or a block copolymer. The polymerization method is not particularly limited, and polymerization can be carried out by a general polymerization method, for example, a solution polymerization method.

By reacting the acrylic polymer (a1) having the functional group-containing monomer unit with the unsaturated group-containing compound (a2) having a functional group bonded to the functional group, the active energy ray-curable polymer (A) ) Is obtained.

The functional group of the unsaturated group-containing compound (a2) can be appropriately selected depending on the type of the functional group of the functional group-containing monomer unit of the acrylic polymer (a1). For example, when the functional group of the acrylic polymer (a1) is a hydroxy group, an amino group or an amide group, the functional group of the unsaturated group-containing compound (a2) is preferably an isocyanate group or an epoxy group, and the acrylic weight is preferable. When the functional group of the coalescence (a1) is a glycidyl group, the functional group of the unsaturated group-containing compound (a2) is preferably an amino group, a carboxy group or an aziridinyl group.

Further, the unsaturated group-containing compound (a2) contains at least one, preferably 1 to 6, and more preferably 1 to 4 active energy ray-polymerizable carbon-carbon double bonds in one molecule. It has been. Specific examples of such an unsaturated group-containing compound (a2) include 2-methacryloyloxyethyl isocyanate, meta-isopropenyl-α, α-dimethylbenzyl isocyanate, methacryloyl isocyanate, allyl isocyanate, 1,1-( Bisacrylloyloxymethyl) ethyl isocyanate; Acryloyl monoisocyanate compound obtained by reacting a diisocyanate compound or polyisocyanate compound with hydroxyethyl (meth) acrylate; a diisocyanate compound or polyisocyanate compound, a polyol compound, and (meth) acrylic. Acryloyl monoisocyanate compound obtained by reaction with hydroxyethyl acid acid; glycidyl (meth) acrylate; (meth) acrylic acid, 2- (1-aziridinyl) ethyl (meth) acrylate, 2-vinyl-2-oxazoline, 2 − Isocyanyl-2-oxazoline and the like.

The unsaturated group-containing compound (a2) is preferably 50 mol% or more, particularly preferably 60 mol% or more, still more preferably 70, based on the number of moles of the functional group-containing monomer of the acrylic polymer (a1). It is used in a proportion of mol% or more. The unsaturated group-containing compound (a2) is preferably 95 mol% or less, particularly preferably 93 mol% or less, still more preferably 93 mol% or less, based on the number of moles of the functional group-containing monomer of the acrylic polymer (a1). Is used in a proportion of 90 mol% or less.

In the reaction between the acrylic polymer (a1) and the unsaturated group-containing compound (a2), the combination of the functional group of the acrylic polymer (a1) and the functional group of the unsaturated group-containing compound (a2) is used. Depending on the reaction temperature, pressure, solvent, time, presence / absence of catalyst, and type of catalyst can be appropriately selected. As a result, the functional group present in the acrylic polymer (a1) reacts with the functional group in the unsaturated group-containing compound (a2), and the unsaturated group is a side chain in the acrylic polymer (a1). The active energy ray-curable polymer (A) is obtained.

The weight average molecular weight (Mw) of the active energy ray-curable polymer (A) thus obtained is preferably 10,000 or more, particularly preferably 150,000 or more, and further 200,000 or more. It is preferable to have. The weight average molecular weight (Mw) is preferably 1.5 million or less, particularly preferably 1 million or less, and further preferably 800,000 or less. The weight average molecular weight (Mw) in the present specification is a standard polystyrene-equivalent value measured by a gel permeation chromatography method (GPC method).

Even when the active energy ray-curable pressure-sensitive adhesive contains a polymer having active energy ray-curable property such as the active energy ray-curable polymer (A) as a main component, the active energy ray-curable pressure-sensitive adhesive has active energy. It may further contain a linear curable monomer and / or oligomer (B).

As the active energy ray-curable monomer and / or oligomer (B), for example, an ester of a polyhydric alcohol and (meth) acrylic acid can be used.

Examples of the active energy ray-curable monomer and / or oligomer (B) include monofunctional acrylic acid esters such as cyclohexyl (meth) acrylate and isobornyl (meth) acrylate, trimethyl propantri (meth) acrylate, and the like. 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 Examples thereof include polyfunctional acrylic acid esters such as glycol di (meth) acrylate and dimethylol tricyclodecandi (meth) acrylate, polyester oligo (meth) acrylate, and polyurethane oligo (meth) acrylate.

When the active energy ray-curable monomer and / or the oligomer (B) is blended with the active energy ray-curable polymer (A), the active energy ray-curable monomer and / or the active energy ray-curable monomer in the active energy ray-curable pressure-sensitive adhesive. Alternatively, the content of the oligomer (B) is preferably more than 0 parts by mass, particularly preferably 60 parts by mass or more, with respect to 100 parts by mass of the active energy ray-curable polymer (A). The content is preferably 250 parts by mass or less, and particularly preferably 200 parts by mass or less, with respect to 100 parts by mass of the active energy ray-curable polymer (A).

Here, when ultraviolet rays are used as the active energy rays for curing the active energy ray-curable pressure-sensitive adhesive, it is preferable to add the photopolymerization initiator (C). By using this photopolymerization initiator (C), the polymerization curing time and the amount of light irradiation can be reduced.

Specific examples of the photopolymerization initiator (C) include 4- (2-hydroxyethoxy) phenyl (2-hydroxy-2-propyl) ketone, α-hydroxy-α, α'-dimethylacetophenone, and 2-methyl-2. Α-Ketol compounds such as −hydroxypropiophenone, 1-hydroxycyclohexylphenylketone; methoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxyacetophenone, 2-methyl-1- [4 -(Methylthio) -phenyl] -2-acetophenone compounds such as morpholinopropane-1; benzoin ether compounds such as benzoin ethyl ether, benzoin isopropyl ether and anisoin methyl ether; ketal compounds such as benzyl dimethyl ketal; 2- Aromatic sulfonyl chloride compounds such as naphthalene sulfonyl chloride; photoactive oxime compounds such as 1-phenone-1,1-propandion-2- (o-ethoxycarbonyl) oxime; benzophenone, benzoylbenzoic acid, 3,3' -Benzophenone compounds such as dimethyl-4-methoxybenzophenone; thioxanson, 2-chlorothioxanson, 2-methylthioxanson, 2,4-dimethylthioxanson, isopropylthioxanson, 2,4-dichlorothioxanson , 2,4-Diethylthioxanson, 2,4-diisopropylthioxanson and other thioxanson compounds; camphorquinone; ketone halides; acylphosphinoxide; acylphosphonate; oligo [2-hydroxy-2-methyl -1- (4- (1-methylvinyl) phenyl) propanone] and the like can be exemplified.

From the viewpoint that the photopolymerization initiator (C) can easily adjust the adhesive force of the adhesive sheet for workpiece processing after fluorescent lamp treatment to the silicon wafer measured in warm water at 90 ° C. within the above-mentioned range. , It is preferable that it is an oligomer-type photopolymerization initiator. In this case, the weight average molecular weight of the photopolymerization initiator (C) is preferably 300 or more, and particularly preferably 450 or more. On the other hand, the upper limit of the weight average molecular weight may be, for example, 900 or less, and in particular, 750 or less. Preferred examples of the oligomer-type photopolymerization initiator include oligo [2-hydroxy-2-methyl-1- (4- (1-methylvinyl) phenyl) propanone].

The above-mentioned photopolymerization initiator (C) may be used alone or in combination of two or more.

When the photopolymerization initiator (C) contains the active energy ray-curable polymer (A) (active energy ray-curable monomer and / or oligomer (B), the active energy ray-curable polymer (A) ) And the total amount of the active energy ray-curable monomer and / or oligomer (B) 100 parts by mass) 0.05 parts by mass or more, particularly 0.07 parts by mass or more, and further 1 part by mass or more with respect to 100 parts by mass. It is preferable to use the amount of. When the content of the photopolymerization initiator (C) is 0.05 parts by mass or more, it becomes easy to satisfactorily accelerate the curing of the pressure-sensitive adhesive layer by irradiation with active energy rays. As a result, the adhesive force to the work is satisfactorily lowered, and it becomes easy to achieve excellent separability to the work. When the photopolymerization initiator (C) contains the active energy ray-curable polymer (A) (active energy ray-curable monomer and / or oligomer (B), the photopolymerization initiator (C) is an active energy ray-curable polymer. (A) and the total amount of the active energy ray-curable monomer and / or oligomer (B) 100 parts by mass) Less than 3.0 parts by mass, particularly 2.0 parts by mass or less, and even 1. It is preferably used in an amount of 0 parts by mass or less. When the content of the photopolymerization initiator (C) is less than 3.0 parts by mass, the pressure-sensitive adhesive sheet for workpiece processing after fluorescent lamp treatment is measured with respect to a silicon wafer measured in warm water at 90 ° C. The adhesive strength can be easily adjusted within the above-mentioned range.

In the active energy ray-curable pressure-sensitive adhesive, other components may be appropriately added in addition to the above components. Examples of other components include an active energy ray non-curable polymer component or an oligomer component (D), a cross-linking agent (E), and the like.

Examples of the active energy ray non-curable polymer component or oligomer component (D) include polyacrylic acid esters, polyesters, polyurethanes, polycarbonates, polyolefins, etc., and polymers having a weight average molecular weight (Mw) of 3000 to 2.5 million or Oligomers are preferred. By blending the component (D) with an active energy ray-curable pressure-sensitive adhesive, the tackiness and peelability before curing, the strength after curing, the adhesiveness with other layers, the storage stability and the like can be improved. The blending amount of the component (D) is not particularly limited, and is appropriately determined in the range of more than 0 parts by mass and 50 parts by mass or less with respect to 100 parts by mass of the active energy ray-curable polymer (A).

The use of the cross-linking agent (E) is preferable from the viewpoint that the storage elastic modulus of the pressure-sensitive adhesive layer can be easily adjusted to a desired range. As the cross-linking agent (E), a polyfunctional compound having reactivity with a functional group of the active energy ray-curable polymer (A) or the like can be used. Examples of such polyfunctional compounds include isocyanate compounds, epoxy compounds, amine compounds, melamine compounds, aziridine compounds, hydrazine compounds, aldehyde compounds, oxazoline compounds, metal alkoxide compounds, metal chelate compounds, metal salts, ammonium salts, etc. Examples thereof include reactive phenolic resins.

Among these, it is preferable to use a metal chelate compound as a cross-linking agent from the viewpoint that the pressure-sensitive adhesive layer easily exhibits plating resistance. Examples of the metal chelate compound include an aluminum chelate compound, a titanium chelate compound, a zirconium chelate compound and the like.

Examples of the above aluminum chelate compounds include aluminum acetylacetonate (trisacetylacetonatoaluminum), aluminum trisethylacetate, and aluminum ethylacetate diisopropirate (diisopropoxyaluminum 3-ethoxycarbonyl-2-propen-2-). (Iloxide) and the like. Examples of the titanium chelate compound include tetrakis (2,4-pentanedionato) titanium and the like. Examples of the zirconium chelate compound include tetrakis (2,4-pentanedionato) zirconium.

The blending amount of the cross-linking agent (E) is preferably 0.01 part by mass or more, particularly 0.1 part by mass or more, with respect to 100 parts by mass of the active energy ray-curable polymer (A). preferable. The amount of the cross-linking agent (E) to be blended is preferably 20 parts by mass or less, and particularly preferably 10 parts by mass or less, based on 100 parts by mass of the active energy ray-curable polymer (A).

Next, in the case where the active energy ray-curable pressure-sensitive adhesive contains a mixture of an active energy ray-curable polymer component and a monomer and / or an oligomer having at least one active energy ray-curable group as a main component. This will be described below.

As the active energy ray non-curable polymer component, for example, the same component as the acrylic polymer (a1) described above can be used.

As the monomer and / or oligomer having at least one or more active energy ray-curable groups, the same one as the above-mentioned component (B) can be selected. The blending ratio of the active energy ray non-curable polymer component to the monomer and / or oligomer having at least one active energy ray curable group is at least 1 with respect to 100 parts by mass of the active energy ray non-curable polymer component. It is preferably 1 part by mass or more of the monomer and / or oligomer having two or more active energy ray-curable groups, and particularly preferably 60 parts by mass or more. The blending ratio is preferably 200 parts by mass or less of the monomer and / or oligomer having at least one active energy ray-curable group with respect to 100 parts by mass of the active energy ray non-curable polymer component. In particular, it is preferably 160 parts by mass or less.

In this case as well, the photopolymerization initiator (C) and the cross-linking agent (E) can be appropriately blended in the same manner as described above.

The thickness of the pressure-sensitive adhesive layer is preferably 1 μm or more, and particularly preferably 5 μm or more. The thickness of the pressure-sensitive adhesive layer is preferably 60 μm or less, and particularly preferably 40 μm or less. When the thickness of the pressure-sensitive adhesive layer is within the above range, the pressure-sensitive adhesive sheet for work processing according to the present embodiment can easily exhibit the desired adhesiveness.

(3) Release sheet In the adhesive sheet for work processing according to the present embodiment, the release sheet may be laminated on the adhesive surface of the adhesive layer. This release sheet may be a process material for forming the pressure-sensitive adhesive layer, or may protect the adhesive surface of the pressure-sensitive adhesive layer until the pressure-sensitive adhesive sheet for work processing is attached to the work. .. The release sheet may be omitted in the work adhesive sheet according to the present embodiment.

The structure of the release sheet is arbitrary, and examples thereof include a plastic film peeled 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-based release agent or the like can be used, and among these, a silicone-based release agent capable of obtaining inexpensive and stable performance is preferable. The thickness of the release sheet is not particularly limited, but is usually 20 μm or more and 250 μm or less.

3. 3. Method for Manufacturing Adhesive Sheet for Work Processing The method for producing the adhesive sheet for work processing according to the present embodiment is not particularly limited, and preferably, the adhesive sheet for work processing according to the present embodiment has an adhesive on one side of the base material. Manufactured by stacking layers.

The pressure-sensitive adhesive layer can be laminated on one side of the base material 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 base material. In this case, a pressure-sensitive adhesive composition constituting the pressure-sensitive adhesive layer and, if desired, a coating liquid further containing a solvent or a dispersion medium are prepared, and the peel-treated surface of the release sheet (hereinafter, may be referred to as "peeling surface"). A coating solution is applied onto the coating liquid using a die coater, curtain coater, spray coater, slit coater, knife coater, etc. to form a coating film, and the coating film is dried to form an adhesive layer. be able to. The properties of the coating liquid are not particularly limited as long as it can be applied, and the coating liquid may contain a component for forming the pressure-sensitive adhesive layer as a solute or a dispersoid. The release sheet in this laminate may be peeled off as a process material, or may be used to protect the adhesive surface of the pressure-sensitive adhesive layer until the pressure-sensitive adhesive sheet for work processing is attached to the work.

When the coating liquid for forming the pressure-sensitive adhesive layer contains a cross-linking agent, the inside of the coating film may be changed by changing the above-mentioned drying conditions (temperature, time, etc.) or by separately providing a heat treatment. The cross-linking reaction between the active energy ray-curable polymer (A) or the active energy ray non-curable polymer and the cross-linking agent may be allowed to proceed to form a cross-linked structure in the pressure-sensitive adhesive layer at a desired presence density. In order to allow this cross-linking reaction to proceed sufficiently, after laminating the pressure-sensitive adhesive layer on the base material by the above method or the like, the obtained pressure-sensitive adhesive sheet for work processing is placed in an environment of, for example, 23 ° C. and a relative humidity of 50%. Curing such as leaving it to stand for a day may be performed.

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

4. How to use the work adhesive sheet for work processing The work adhesive sheet according to the present embodiment can be used for processing the work. That is, after the adhesive surface of the work-processing adhesive sheet according to the present embodiment is attached to the work, the work can be processed on the work-processing adhesive sheet. Depending on the processing, the work-processing adhesive sheet according to the present embodiment can be used as a back grind sheet, a dicing sheet, an expanding sheet, a pickup sheet, or the like. Here, examples of the work include semiconductor members such as semiconductor wafers and semiconductor packages, and glass members such as glass plates.

The work-processing adhesive sheet according to the present embodiment can exhibit excellent plating resistance. Therefore, the work-processing adhesive sheet according to the present embodiment is suitable for use for plating the work.

When the machining of the work is completed on the work-processing adhesive sheet according to the present embodiment and the processed work is separated from the work-processing adhesive sheet, the pressure-sensitive adhesive on the work-processing adhesive sheet is prior to the separation. It is preferable to irradiate the layer with active energy rays. As a result, the pressure-sensitive adhesive layer is cured, the adhesive force of the work-processing adhesive sheet to the processed work is satisfactorily reduced, and the processed work can be easily separated. In particular, the work-processing adhesive sheet according to the present embodiment can satisfactorily reduce its adhesive strength by irradiating it with active energy rays even when it is stored for a long period of time under a fluorescent lamp.

As the above-mentioned active energy beam, for example, an electromagnetic wave or a charged particle beam having an energy quantum can be used, and specifically, an ultraviolet ray, an electron beam, or the like can be used. In particular, ultraviolet rays that are easy to handle are preferable. Irradiation of ultraviolet rays, a high-pressure mercury lamp, can be performed by a xenon lamp, LED, etc., the dose of ultraviolet ray is illuminance 50 mW / cm ² or more, and preferably 1000 mW / cm ² or less. Further, the light amount is preferably at 50 mJ / cm ² or more, particularly preferably at 80 mJ / cm ² or more, and further preferably not 200 mJ / cm ² or more. Further, the light amount is preferably at 10000 mJ / cm ² or less, particularly preferably at 5000 mJ / cm ² or less, and further preferably not 2000 mJ / cm ² or less. On the other hand, the irradiation of the electron beam can be performed by an electron beam accelerator or the like, and the irradiation amount of the electron beam is preferably 10 grad or more and 1000 grad or less.

The embodiments described above have been described for facilitating the understanding of the present invention, and have not been described for limiting the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents belonging to the technical scope of the present invention.

For example, the release sheet may not be provided, or another layer may be provided on the surface of the base material opposite to the pressure-sensitive adhesive layer.

Hereinafter, 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) Preparation of Adhesive Composition 69 parts by mass of n-butyl acrylate, 10 parts by mass of methyl methacrylate, 1 part by mass of acrylic acid, and 10 parts by mass of 2-hydroxyethyl acrylate are subjected to a solution polymerization method. The polymerization was carried out to obtain a (meth) acrylic acid ester polymer. This (meth) acrylic acid ester polymer is reacted with methacryloyloxyethyl isocyanate (MOI) corresponding to 80 mol% with respect to 2-hydroxyethyl acrylate in the (meth) acrylic acid ester polymer. An acrylic polymer having an active energy ray-curable group introduced into the side chain was obtained. The weight average molecular weight (Mw) of this acrylic polymer was measured by the method described later and found to be 600,000.

100 parts by mass of the acrylic polymer having an active energy ray-curable group introduced into the side chain obtained above, and an aluminum chelate compound as a cross-linking agent (manufactured by Soken Kagaku Co., Ltd., product name "M-5A") 0 .4 parts by mass and oligo [2-hydroxy-2-methyl-1- (4- (1-methylvinyl) phenyl) propanone] as a photopolymerization initiator (manufactured by DKSH, product name "ESACURE KIP 150") 2.9 parts by mass was mixed in a solvent to obtain a coating liquid for an adhesive composition.

(2) Formation of Adhesive Layer The peeling surface of a release sheet (manufactured by Lintec Corporation, product name "SP-PET38131") in which a silicone-based release agent layer is formed on one side of a polyethylene terephthalate (PET) film having a thickness of 38 μm. On the other hand, a coating liquid of the above-mentioned adhesive composition was applied and dried by heating to form an adhesive layer having a thickness of 10 μm on the release sheet.

(3) Preparation of Adhesive Sheet for Work Processing By laminating the exposed surface of the adhesive layer formed in the above step (2) and one side of a polypropylene film (thickness: 80 μm) as a base material, a release sheet can be obtained. A pressure-sensitive adhesive sheet for work processing was obtained in which the pressure-sensitive adhesive layer and the base material were laminated in this order.

[Examples 2 to 5 and Comparative Examples 1 to 3]
An adhesive sheet for workpiece processing was produced in the same manner as in Example 1 except that the content of the photopolymerization initiator was changed as shown in Table 1.

[Comparative Example 4]
68 parts by mass of n-butyl acrylate, 10 parts by mass of methyl methacrylate, 1 part by mass of acrylic acid, 1 part by mass of acrylonitrile, and 10 parts by mass of 2-hydroxyethyl acrylate were polymerized by a solution polymerization method. , (Meta) acrylic acid ester polymer was obtained. This (meth) acrylic acid ester polymer is reacted with methacryloyloxyethyl isocyanate (MOI) corresponding to 80 mol% with respect to 2-hydroxyethyl acrylate in the (meth) acrylic acid ester polymer. An acrylic polymer having an active energy ray-curable group introduced into the side chain was obtained. The weight average molecular weight (Mw) of this acrylic polymer was measured by the method described later and found to be 600,000.

The acrylic polymer obtained above with an active energy ray-curable group introduced into the side chain was used, and the contents of the cross-linking agent and the photopolymerization initiator were changed as shown in Table 1. An adhesive sheet for workpiece processing was manufactured in the same manner as in Example 1.

The above-mentioned weight average molecular weight (Mw) is a standard polystyrene-equivalent weight average molecular weight measured under the following conditions (GPC measurement) using gel permeation chromatography (GPC).
<Measurement conditions>
-Measuring device: HLC-8320 manufactured by Tosoh Corporation
-GPC column (passed in the following order): TSK gel superH-H manufactured by Tosoh Corporation
TSK gel superHM-H
TSK gel superH2000
・ Measurement solvent: tetrahydrofuran ・ Measurement temperature: 40 ° C

[Test Example 1] (Measurement of adhesive strength in warm water)

The adhesive sheet for workpiece processing produced in Examples and Comparative Examples was cut into a strip-shaped sample having a length of 300 mm and a width of 25 mm. Subsequently, the release sheet is peeled off from one end of the sample to partially expose the pressure-sensitive adhesive layer, and the exposed surface of the pressure-sensitive adhesive layer is mirror-finished in an environment of 23 ° C. and 50% relative humidity. It was superposed on the mirror surface of the 6-inch silicon wafer, and a load was applied by reciprocating a 2 kg roller once to bond them.

Twenty minutes after the bonding, the silicon wafer was submerged in warm water at 90 ° C. At this time, one end of the sample was in a state of being attached to a silicon wafer, and the other end was in a state of going out of hot water. Then, the silicon wafer was heated together with one end of the sample in the warm water for 30 minutes.

After the completion of heating, one end of the sample located outside the hot water was fixed to the measuring shaft of a push-pull gauge (load measuring device) (manufactured by Aiko Engineering Co., Ltd., model "9020A"). Subsequently, the sample was peeled from the silicon wafer by pulling up the push-pull gauge while the silicon wafer was fixed in warm water. At this time, the peeling angle was set to 180 ° and the peeling speed was set to 300 mm / min. Then, the force (mN / 25 mm) required for the peeling was read from the push-pull gauge, and this was used as the adhesive force in warm water. The results are shown in Table 1. In particular, Table 1 shows "measured value (A) without fluorescent lamp treatment".

In addition, the adhesive strength (mN / 25 mm) in warm water was measured in the same manner as above for the adhesive sheets for workpiece processing produced in Examples and Comparative Examples, which were subjected to the following fluorescent lamp treatment. did. The result is shown as "measured value (B) with fluorescent lamp treatment" in Table 1.

The fluorescent lamp treatment was carried out as follows. The adhesive sheet for processing the work was placed on a horizontal table so that the surface on the base material side was on the upper side. Subsequently, the distance from the surface on the base material side becomes 100 cm, and the round tube fluorescent lamp (manufactured by Panasonic, product name "FCL30ECW / 28XF Paruk 30W cool color", glass tube diameter) is parallel to the surface. : 29 mm, outer diameter: 225 mm, inner diameter: 167 mm, mass: 158 g, luminous flux: 2100 lumens) was installed. Then, the round tube fluorescent lamp was turned on and left for 14 days to irradiate visible light from the round tube fluorescent lamp.

Further, the ratio (B / A) (%) of the "measured value (B) with the fluorescent lamp treatment" to the "measured value (A) without the fluorescent lamp treatment" obtained as described above is calculated. The results are also shown in Table 2.

[Test Example 2] (Measurement of adhesive strength after irradiation with active energy rays)
The adhesive sheet for workpiece processing produced in Examples and Comparative Examples was cut into a length of 300 mm and a width of 25 mm to prepare a sample. Subsequently, the release sheet was peeled off from the sample to expose the pressure-sensitive adhesive layer, and the exposed surface of the pressure-sensitive adhesive layer was mirror-processed in an environment of 23 ° C. and 50% relative humidity. It was superposed on the mirror surface of the above, and a load was applied by reciprocating a 2 kg roller once to bond them, and the mixture was left for 20 minutes.

Subsequently, the surface of the adhesive sheet for workpiece processing opposite to the silicon wafer is irradiated with ultraviolet rays (UV) using an ultraviolet irradiation device (manufactured by Lintec Corporation, product name "RAD-2000") (illuminance: 230 mW / cm ² , light intensity: 190 mJ / cm ² ), the pressure-sensitive adhesive layer was cured.

Then, the adhesive sheet for workpiece processing is peeled from the silicon wafer at a peeling speed of 300 mm / min and a peeling angle of 180 °, and the adhesive force (mN / 25 mm) to the silicon wafer is subjected to a 180 ° peeling method according to JIS Z0237: 2000. ) Was measured. The results are shown in Table 2 as the adhesive strength after irradiation with active energy rays. In particular, in Table 2, it is shown as "measured value (C) without fluorescent lamp treatment".

Further, the adhesive force (mN) after irradiation with active energy rays was also applied to the adhesive sheet for workpiece processing produced in Examples and Comparative Examples to which the fluorescent lamp treatment shown in Test Example 1 was performed in the same manner as described above. / 25 mm) was measured. The results are shown in Table 2 as "measured values (D) with fluorescent lamp treatment".

Further, the ratio (D / C) (%) of the "measured value (C) without the fluorescent lamp treatment" to the "measured value (D) with the fluorescent lamp treatment" obtained as described above is calculated. The results are also shown in Table 2.

[Test Example 3] (Evaluation of separability)
The adhesive sheet for workpiece processing produced in Examples and Comparative Examples was subjected to the fluorescent lamp treatment shown in Test Example 1. Then, the release sheet was peeled off from the work-processing adhesive sheet, and the exposed surface of the exposed adhesive layer was attached to the mirror surface of a mirror-processed silicon wafer (diameter: 6 inches, thickness: 150 μm). The sticking conditions at this time were a temperature of 23 ° C., a sticking pressure of 0.3 MPa, and a sticking speed of 5 mm / sec. Next, the outer peripheral portion of the attached adhesive sheet was attached to a resin ring frame under the same conditions.

Subsequently, using a dicing apparatus (manufactured by Disco Corporation, product name "DFD-6361"), dicing was performed by cutting from the silicon wafer side while supplying running water to the cutting portion under the following dicing conditions.

<Dicing conditions>
・ Dicing device: DFD-6361 manufactured by DISCO
-Blade: NBC-2H 2050 27HECC manufactured by DISCO
-Blade width: 0.025 to 0.030 mm
・ Amount of cutting edge: 0.640 to 0.760 mm
・ Blade rotation speed: 50,000 rpm
・ Cutting speed: 20 mm / sec
-Cut depth: 15 μm from the surface on the adhesive layer side of the adhesive sheet for workpiece processing
・ Running water supply: 1.0 L / min
・ Running water temperature: Room temperature ・ Cut size: 10mm x 10mm

After dicing is completed, the surface on the adhesive sheet side for workpiece processing is irradiated with ultraviolet rays using an ultraviolet irradiation device (manufactured by Lintec Corporation, product name "RAD-2000") (illuminance: 230 mW / cm ² , light intensity: 190 mJ / cm). ² ) The pressure-sensitive adhesive layer was cured. Then, 10 pieces were randomly picked up from the work-processing adhesive sheet from the obtained chips.

At this time, the adhesive sheet for workpiece processing was expanded by pulling down the ring frame at a speed of 5 mm / s by 5 mm using an expanding device (manufactured by JCM, product name “SE-100”). Further, the adhesive sheet for workpiece processing was pushed up by a needle from the surface opposite to the surface on which the glass tip was attached (number of needles: 4, push-up speed: 50 mm / sec, push-up height: 0.5 mm). ).

Then, in the 10 chips picked up, adhesive residue and cracks were confirmed, and the separability when separating the chips from the adhesive sheet for workpiece processing was evaluated based on the following criteria. The results are shown in Table 2.
⊚: The number of chips having neither adhesive residue nor cracks was 10.
◯: The number of chips having neither adhesive residue nor cracks was 9 to 6.
X: The number of chips having neither adhesive residue nor cracks was 5 to 0.

[Test Example 4] (Evaluation of plating resistance)
The adhesive sheet for workpiece processing produced in Examples and Comparative Examples was subjected to the fluorescent lamp treatment shown in Test Example 1. Then, the release sheet was peeled off from the work-processing adhesive sheet, and the exposed surface of the exposed adhesive layer was attached to the mirror surface of a mirror-processed silicon wafer (diameter: 6 inches, thickness: 150 μm). The sticking conditions at this time were a temperature of 23 ° C., a sticking pressure of 0.3 MPa, and a sticking speed of 5 mm / sec. Next, the outer peripheral portion of the attached adhesive sheet was attached to a resin ring frame under the same conditions.

Subsequently, the adhesive sheet for workpiece processing to which the silicon wafer and the ring frame were attached was immersed in a nickel plating solution heated to 80 ° C. (manufactured by C. Uyemura & Co., Ltd., product name "Epitas NPR-18") for 20 minutes. After that, with respect to the adhesive sheet for work processing pulled up from the nickel plating solution, the penetration of the nickel plating solution and the generation of air bubbles at the interface with the silicon wafer were visually confirmed, and the adhesive for work processing was adhered based on the following criteria. The plating resistance of the sheet was evaluated. The results are shown in Table 2.
◯: No penetration of nickel plating solution and no bubbles were generated.
X: Infiltration of nickel plating solution and at least one of air bubbles occurred.

Details of the abbreviations and the like shown in Table 1 are as follows.
BA: n-butyl acrylate MMA: methyl methacrylate AA: acrylate HEA: 2-hydroxyethyl acrylate MOI: methacryloyloxyethyl isocyanate AN: acrylonitrile

As can be seen from Table 2, the adhesive sheet for workpiece processing obtained in the examples can exhibit good separability by irradiating with active energy rays even when subjected to fluorescent lamp treatment. did it. Further, the adhesive sheet for workpiece processing obtained in the examples had excellent plating resistance.

The adhesive sheet for processing a work of the present invention can be used for processing a work, particularly a work including a plating process.

Claims (10)

A pressure-sensitive adhesive sheet for work processing, comprising a base material and a pressure-sensitive adhesive layer laminated on one side of the base material.
The pressure-sensitive adhesive layer is made of an active energy ray-curable pressure-sensitive adhesive.
Using a fluorescent lamp arranged 100 cm away from the surface of the base material opposite to the pressure-sensitive adhesive layer as a light source, a fluorescent lamp treatment was performed in which the surface was irradiated with visible light having a luminous flux of 2100 lumens for 14 days. The adhesive sheet for workpiece processing, which will be described later, has an adhesive force to a silicon wafer measured in warm water at 90 ° C. of 1600 mN / 25 mm or more. A claim that the adhesive sheet for workpiece processing which has not been subjected to the fluorescent lamp treatment has an adhesive force with respect to a silicon wafer measured in warm water at 90 ° C. of 3000 mN / 25 mm or more and 30,000 mN / 25 mm or less. The adhesive sheet for workpiece processing according to 1. The adhesive sheet for work processing that has not been subjected to the fluorescent lamp treatment has a resistance to the adhesive force to the silicon wafer measured in warm water at 90 ° C., and the adhesive sheet for work processing that has been subjected to the fluorescent lamp treatment has hot water at 90 ° C. The pressure-sensitive adhesive sheet for workpiece processing according to claim 2, wherein the ratio of the adhesive force to the silicon wafer measured inside is 35% or more. The adhesive force against the silicon wafer after irradiation with the active energy ray in the adhesive sheet for work processing not subjected to the fluorescent lamp treatment, and the silicon wafer after irradiation with the active energy ray in the adhesive sheet for work processing subjected to the fluorescent lamp treatment. The adhesive sheet for workpiece processing according to any one of claims 1 to 3, wherein the ratio of the adhesive force to the silicon is 90% or more and 140% or less. Any of claims 1 to 4, wherein the adhesive force for processing a work subjected to the fluorescent lamp treatment has an adhesive force to a silicon wafer after irradiation with active energy rays of 50 mN / 25 mm or more and 320 mN / 25 mm or less. The adhesive sheet for workpiece processing described in item 1. The active energy ray-curable pressure-sensitive adhesive is formed from a pressure-sensitive adhesive composition containing an acrylic polymer having an active energy ray-curable group introduced into a side chain, a cross-linking agent, and a photopolymerization initiator. The adhesive sheet for workpiece processing according to any one of claims 1 to 5, wherein the adhesive sheet for workpiece processing is characterized. The pressure-sensitive adhesive sheet for workpiece processing according to claim 6, wherein the photopolymerization initiator is an oligomer-type photopolymerization initiator. The content of the photopolymerization initiator in the adhesive composition is 0.05 parts by mass or more and 3 parts by mass or more with respect to 100 parts by mass of the acrylic polymer in which the active energy ray-curable group is introduced into the side chain. The adhesive sheet for workpiece processing according to claim 6 or 7, wherein the amount is less than 0.0 parts by mass. The pressure-sensitive adhesive sheet for workpiece processing according to any one of claims 6 to 8, wherein the cross-linking agent is a metal chelate compound. The acrylic polymer is characterized in that it does not contain a monomer having a cyano group or contains 0.2% by mass or less of a monomer having a cyano group as a monomer unit constituting the polymer. The adhesive sheet for workpiece processing according to any one of 6 to 9.