JP2022156385A - Workpiece processing sheet - Google Patents

Abstract

To provide a workpiece processing sheet which suppresses an adhesive residue on a workpiece.SOLUTION: There are provided workpiece processing sheets 1A, 1B, 1C comprising substrates 11a, 11b, 11c and an adhesive layer 12 laminated on one surface side of the substrates 11a, 11b, 11c, wherein the content of a tin atom in the adhesive layer 12 is 0.002 mass% or more and 0.015 mass% or less.SELECTED DRAWING: Figure 1

Description

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.

When a sheet having an adhesive layer exhibiting active energy ray-curability is used as the work processing sheet, the work processing sheet is removed from the processed work by reducing the adhesive force by irradiating the work with the active energy ray. It becomes possible to peel off easily. Patent Literature 1 discloses such a work processing sheet.

JP 2010-106283 A

By the way, the work processing sheet may become electrified during transportation or use, and such electrification may cause damage to the semiconductor chips or the like and malfunction of the dicing device or the like. For example, when separating a processed work from a work processing sheet, static electricity called separation electrification may occur between the work processing sheet and the processed work. If the processed workpiece is, for example, a semiconductor chip, the generation of such static electricity causes destruction of circuits and the like formed on the chip.

For this reason, it has been considered to prevent electrification by imparting an antistatic function to the work processing sheet. For example, it is being considered to provide an antistatic layer containing an antistatic agent between the base material and the pressure-sensitive adhesive layer. However, in the work processing sheet provided with such an antistatic layer, when the processed work is separated from the work processing sheet, the adhesive constituting the adhesive layer adheres to the processed work. The inventors have confirmed that (hereinafter sometimes referred to as "adhesive residue") tends to occur.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a work processing sheet in which adhesive residue on a work is suppressed.

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 tin atoms in the adhesive layer content is 0.002% by mass or more and 0.015% by mass or less (Invention 1).

In the work processing sheet according to the above invention (invention 1), the content of tin atoms in the adhesive layer is within the above range, so that the base material has an antistatic layer (including an "organic conductive film" described later). Even if it is provided, the adhesion of the adhesive layer to the base material (or antistatic layer) will be good, and the occurrence of adhesive residue on the processed work separated from the adhesive layer will be suppressed. Become.

In the above invention (invention 1), the pressure-sensitive adhesive layer is preferably composed of an active energy ray-curable pressure-sensitive adhesive (invention 2).

In the above invention (invention 2), the active energy ray-curable pressure-sensitive adhesive preferably contains an active energy ray-curable polymer and a tin-containing catalyst containing tin atoms (invention 3).

In the above invention (Invention 3), the active energy ray-curable polymer is a (meth)acrylic acid ester polymer having an active energy ray-curable group introduced into a side chain, and the (meth)acrylic acid ester The polymer is obtained by reacting an acrylic copolymer having functional group-containing monomer units and an unsaturated group-containing compound having a functional group that binds to the functional group by the catalytic action of the tin-containing catalyst. (Invention 4).

In the above inventions (inventions 1 to 4), the surface resistivity of the surface of the base material on which the adhesive layer is laminated is preferably 1×10 ¹⁰ Ω/□ or less (invention 5).

In the above inventions (Inventions 1 to 5), it is preferable that the substrate has an organic conductive film on the surface on which the pressure-sensitive adhesive layer is laminated (Invention 6).

The above inventions (Inventions 1 to 6) are preferably used for dicing (Invention 7).

The work processing sheet according to the present invention can suppress adhesive residue on the work.

1 is a cross-sectional view of a work processing sheet according to an embodiment of the present invention; FIG. FIG. 4 is a cross-sectional view of a work processing sheet according to another embodiment of the present invention; FIG. 5 is a cross-sectional view of a work processing sheet according to still another embodiment of the present invention;

Embodiments of the present invention will be described below.
A work processing sheet according to the present embodiment includes a substrate and an adhesive layer laminated on one side of the substrate. In the work processing sheet according to the present embodiment, the content of tin atoms in the adhesive layer is 0.002% by mass or more and 0.015% by mass or less.

In general, when using a work processing sheet, after a work is attached to the surface of the adhesive layer of the work processing sheet opposite to the base material (hereinafter sometimes referred to as "adhesive surface"), the work is Predetermined processing is performed on the workpiece on the processing sheet. Subsequently, (when the adhesive layer is made of an active energy ray-curable adhesive, after curing the adhesive layer by irradiating the adhesive layer with an active energy ray), after processing from the work processing sheet Separate the work. At the time of this separation, the conventional work processing sheet tends to leave an adhesive residue as described above.

However, in the work processing sheet according to the present embodiment, the content of tin atoms in the pressure-sensitive adhesive layer is within the above range, so that the adhesiveness between the substrate and the pressure-sensitive adhesive layer is improved. This suppresses the occurrence of peeling at the interface between the substrate and the pressure-sensitive adhesive layer that accompanies separation of the work from the work processing sheet. As a result, the adhesion of the adhesive constituting the adhesive layer to the work to be separated is suppressed. That is, the adhesive residue on the work is suppressed satisfactorily.

In addition, as a general means for improving the adhesion between the substrate and the pressure-sensitive adhesive layer, the surface of the substrate on which the pressure-sensitive adhesive layer is to be provided may be subjected to surface treatment such as corona treatment. However, when a film (organic conductive film) for the purpose of antistatic is provided on the surface of the substrate, from the viewpoint of avoiding the destruction of the organic conductive film, the surface of the organic conductive film surface treatment such as corona treatment cannot be performed. Therefore, when using the substrate provided with the above-described organic conductive film, there is a problem that adhesive deposits are particularly likely to occur.

However, according to the work processing sheet according to the present embodiment, as in the case where the organic conductive film is provided on the surface of the base material, it is possible to increase the adhesion between the base material and the adhesive layer. Even if surface treatment cannot be performed, excellent adhesion can be achieved between the substrate and the pressure-sensitive adhesive layer, and the occurrence of adhesive residue can be effectively suppressed.

From the viewpoint of further increasing the adhesion between the substrate and the adhesive layer, the upper limit of the tin atom content in the adhesive layer is preferably 0.014% or less, particularly 0.013% or less. Preferably. From the same point of view, the lower limit of the tin atom content in the pressure-sensitive adhesive layer is preferably 0.0022% or more, particularly preferably 0.0024% or more.

The origin of the tin atoms in the pressure-sensitive adhesive layer in this embodiment may be a tin-containing catalyst as a material for forming the pressure-sensitive adhesive layer, as will be described later. In this case, by adjusting the amount of the tin-containing catalyst used so that the content of tin atoms in the adhesive layer is within the range described above, the desired performance such as adhesiveness can be achieved while reducing adhesive residue. It is possible to obtain a work processing sheet that can be suppressed to .

The content of tin atoms in the adhesive layer in the present embodiment may be determined by quantitative analysis, and is calculated from the composition of the material used to form the adhesive layer (for example, the adhesive composition described later). It may be something that is required by

Although the type of quantitative analysis is not particularly limited, one example is the following method. First, 50 mg of the adhesive constituting the adhesive layer is sampled and pretreated by a pressurized acid decomposition method. After that, the content of tin atoms in the adhesive can be obtained by inductively coupled plasma mass spectrometry (ICP-MS) (for example, a device manufactured by Agilent Technologies is used).

Examples of the work for which the work processing sheet according to the present embodiment is used include semiconductor members such as semiconductor chips, semiconductor wafers and semiconductor packages, and glass members such as glass chips and glass plates.

1. Constituent Members of Work Processing Sheet FIGS. 1 to 3 show an example of a work processing sheet according to the present embodiment.
The work processing sheet 1A shown in FIG. 1 includes a base film 111 and an organic conductive film 112 provided on both sides of the base film 111, and an adhesive layer 12 laminated on one side of the base film 11a. .

The work processing sheet 1B shown in FIG. 2 is laminated on a substrate 11b having an organic conductive film 112 provided on one side of a base film 111 and a surface of the substrate 11a provided with the organic conductive film 112. and an adhesive layer 12 .

A work processing sheet 1C shown in FIG. 3 includes a substrate 11c composed of a base film 111' containing an antistatic agent, and an adhesive layer 12 laminated on one side of the substrate 11c.

(1) Substrate The substrate in the present embodiment is not particularly limited as long as it exhibits the desired function in the process of using the work processing sheet. 1 and 2, the base film 111 may be provided with an organic conductive film 112 on one or both sides thereof, and as shown in FIG. may consist of only the base film 111' containing Furthermore, the substrate in the present embodiment may consist of only the base film 111 that does not include the organic conductive film 112 and does not contain an antistatic agent, and both sides of the base film 111' containing an antistatic agent or The organic conductive film 112 may be provided on one side.

In the work processing sheet according to the present embodiment, as described above, even if the substrate cannot be subjected to a surface treatment for improving the adhesion between the substrate and the adhesive layer, adhesive residue is generated. can be effectively suppressed. Therefore, as shown in FIGS. 1 and 2, it is preferable that the base material in the present embodiment is provided with an organic conductive film 112, since the effect of suppressing adhesive deposits is high.

(1-1) Base film The base film 111 is preferably a resin film mainly composed of a resin-based material. Specific examples thereof include ethylene-vinyl acetate copolymer film; ethylene-(meth) Ethylene-based copolymer films such as acrylic acid copolymer films, ethylene-(meth)methyl acrylate copolymer films, and other ethylene-(meth)acrylate copolymer films; polyethylene films, polypropylene films, polybutene films , polybutadiene film, polymethylpentene film, ethylene-norbornene copolymer film, norbornene resin film and other polyolefin films; polyvinyl chloride film, polyvinyl chloride copolymer film and other polyvinyl chloride films; polyethylene terephthalate film, poly polyester films such as butylene terephthalate film and polyethylene naphthalate; (meth)acrylate copolymer film; polyurethane film; polyimide film; polystyrene film; polycarbonate film; Examples of polyethylene films include low density polyethylene (LDPE) films, linear low density polyethylene (LLDPE) films, high density polyethylene (HDPE) films, and the like. Modified films such as these crosslinked films and ionomer films are also used. Preferred examples of the base film 111' include those films containing an antistatic agent. In addition, when the adhesive layer 12 is made of an active energy ray-curable adhesive, the base film 111 and the base film 111' are resistant to the active energy ray irradiated for curing the adhesive layer 12. It is preferably made of a material that exhibits good permeability.

Also, the base film 111 may be a laminated film formed by laminating a plurality of films described above. In this laminated film, the materials constituting each layer may be of the same type or of different types. The base film 111' may also be a laminated film. In this case, all layers constituting each layer may contain an antistatic agent, or at least one layer may contain an antistatic agent. can be anything.

As the base film 111, among the above films, it is preferable to use an ethylene-methyl methacrylate copolymer film from the viewpoint of excellent flexibility. Also for the base film 111', it is preferable to use an ethylene-methyl methacrylate copolymer film containing an antistatic agent. In addition, "(meth)acrylic acid" in this specification means both acrylic acid and methacrylic acid. The same is true for other similar terms.

The base film 111 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 within a range in which the base film 111 exhibits the desired functions. The base film 111' may also contain the various additives described above in addition to the antistatic agent.

The surface of the base film 111 on which the organic conductive film 112 is laminated may be subjected to surface treatment such as primer treatment, corona treatment, plasma treatment, etc., in order to improve adhesion with the organic conductive film 112 .

(1-2) Organic Conductive Film The organic conductive film 112 is not particularly limited as long as it can exhibit desired functions such as antistatic properties.

The organic conductive film 112 preferably contains a conductive material and a binder resin. Examples of conductive materials include conductive polymers, conductive fillers, anionic and cationic compounds, and compounds having quaternary ammonium bases in the main chain or side chain in the molecule.

Examples of the conductive polymer include polythiophene-based, polyaniline-based, and polypyrrole-based conductive polymers. Examples of polythiophene-based conductive polymers include polythiophene, poly(3-alkylthiophene), poly(3-thiophene-β-ethanesulfonic acid), and a mixture of polyalkylenedioxythiophene and polystyrenesulfonate. . Examples of polyalkylenedioxythiophenes include polyethylenedioxythiophene, polypropylenedioxythiophene, poly(ethylene/propylene)dioxythiophene, and the like. Polyaniline-based conductive polymers include, for example, polyaniline, polymethylaniline, and polymethoxyaniline. Polypyrrole-based conductive polymers include, for example, polypyrrole, poly-3-methylpyrrole, and poly-3-octylpyrrole. One of these conductive polymer compounds may be used alone, or two or more thereof may be used in combination. These conductive polymers are preferably dispersed in water and used in the form of an aqueous solution.

Examples of conductive fillers include gold, silver, copper, nickel, aluminum, stainless steel, carbon, conductive ceramics, tin oxide, antimony-doped tin oxide (ATO), indium-tin oxide (ITO), zinc oxide, Particles such as antimony oxide are included.

Examples of anionic and cationic compounds include ionic liquids, ionic solids, anionic surfactants, alkali metal salts, cationic surfactants and nonionic surfactants. Examples of ionic liquids and ionic solids include nitrogen-containing onium salts, sulfur-containing onium salts, phosphorus-containing onium salts, and the like. Alkali metal salts include lithium salts, potassium salts and the like. These may be used alone or in combination of two or more.

Specific examples of compounds having a quaternary ammonium base include pyrrolidium rings, quaternized alkylamines, copolymers thereof with acrylic acid or methacrylic acid, quaternized N-alkylaminoacrylamides, vinyl benzyltrimethylammonium salt, 2-hydroxy-3-methacryloxypropyltrimethylammonium salt and the like.

The compound having the quaternary ammonium base is desirably a polymer compound. The number average molecular weight of the compound having a quaternary ammonium base is preferably 1,000 or more, particularly preferably 2,000 or more, further preferably 5,000 or more. Regarding the upper limit of the number average molecular weight, the number average molecular weight is preferably 500,000 or less from the viewpoint of preventing the viscosity of the coating liquid containing the conductive material from becoming too high. In addition, the number average molecular weight in this specification is the value of standard polystyrene conversion measured by the gel permeation chromatography (GPC) method.

The content of the conductive material in the organic conductive film 112 is preferably 1% by mass or more, particularly preferably 5% by mass or more. Moreover, the content is preferably 30% by mass or less, and particularly preferably 20% by mass or less. When the content of the conductive material is 1% by mass or more, desired functions such as antistatic properties are effectively exhibited. Further, when the content of the conductive polymer is 30% by mass or less, the ratio of the binder resin in the organic conductive film 112 becomes sufficient, and the coating film strength of the organic conductive film 112 itself becomes good. .

Examples of binder resins include melamine resins, polyesters, polyurethanes, acrylic resins, vinyl resins, epoxy resins, amide resins, and polyvinyl alcohol. Examples of melamine resins include methylated melamine resins, butylated melamine resins, methyl/butylated melamine resins, etc. Among these, butylated melamine resins are preferred. These binder resins may have a composite skeleton structure due to copolymerization or the like. Examples of the binder resin having a composite structure include acrylic resin-grafted polyester, acrylic resin-grafted polyurethane, vinyl resin-grafted polyester, and vinyl resin-grafted polyurethane.

The organic conductive film 112 may further contain a cross-linking reactive compound. The crosslinkable compound can be obtained by adding a crosslinker to a coating liquid containing a conductive material and causing a crosslink reaction with the functional groups of the compound contained in the coating liquid. By including a cross-linking agent in the coating liquid, the water resistance, solvent resistance, mechanical strength, etc. of the organic conductive film 112 are improved.

Examples of cross-linking agents include melamine-based cross-linking agents and epoxy-based cross-linking agents. Examples of the melamine-based cross-linking agent include alkylol- or alkoxyalkylol-modified melamine-based compounds such as methoxymethylated melamine and butoxymethylated melamine. good too. As the epoxy-based cross-linking agent, it is preferable to use a compound having an epoxy group that is water-soluble or has a water solubility of 50% or more.

The organic conductive film 112 may contain at least one additive such as an antifoaming agent, a coatability improver, a thickener, an organic lubricant, organic particles, inorganic particles, etc., if necessary.

The organic conductive film 112 can be formed by applying a coating liquid containing the above-described conductive polymer, binder resin, etc. to one or both sides of the base film 111 and drying the obtained coating film.

Although the thickness of the organic conductive film 112 can be appropriately set according to the method of using the work processing sheet, it is usually preferably 0.003 μm or more, particularly preferably 0.005 μm or more. Also, the thickness is preferably 1.5 μm or less, particularly preferably 0.5 μm or less.

(1-3) Antistatic agent in the base film When the substrate according to the present embodiment consists only of the base film 111 ' containing the antistatic agent, the antistatic contained in the base film 111 ' The agent is not particularly limited as long as it can impart the desired antistatic properties.

Preferred antistatic agents include low-molecular-weight antistatic agents, high-molecular-weight antistatic agents, metal oxides, carbon materials, and the like, with high-molecular-weight antistatic agents being particularly preferred. Examples of the polymer-type antistatic agent include vinyl copolymers having a sulfonate in the molecule, alkylsulfonates, alkylbenzenesulfonates, betaine, and the like. In particular, inorganic protonic acid salts of polyethers, polyamide elastomers, polyester elastomers, polyetheramides or polyetheresteramides can be mentioned. Examples of salts of inorganic protic acids include alkali metal, alkaline earth metal, zinc or ammonium salts.

The content of the antistatic agent in the base film 111' is preferably 3% by mass or more and 20% by mass or less. When the content of the antistatic agent is within the above range, the resulting base film 111' tends to have good antistatic properties.

(1-4) Physical Properties of Base Material The surface resistivity of the side of the base material 11 on which the adhesive layer is laminated is preferably 1×10 ¹² Ω/□ or less, particularly 5×10 ¹¹ Ω. /□ or less, more preferably 1×10 ¹¹ Ω/□ or less. When the substrate 11 exhibits the surface resistivity described above, the work processing sheet can easily exhibit excellent antistatic properties. The lower limit of the surface resistivity is not particularly limited, and may be, for example, 1×10 ⁴ Ω/□ or more, particularly 1×10 ⁵ Ω/□ or more. The details of the method for measuring the surface resistivity are as described in the test examples described later.

The thickness of the base material 11 (the thickness including the organic conductive film 112 when provided with the organic conductive film 112) can be appropriately set according to the method in which the work processing sheet is used, but is usually 20 μm or more. It is preferably 25 μm or more, particularly preferably 25 μm or more. Also, the thickness is usually preferably 450 μm or less, particularly preferably 300 μm or less.

(2) Adhesive layer In the work processing sheet according to the present embodiment, the adhesive layer contains tin atoms in the above-described content, and has sufficient adhesive strength to the adherend (especially, when processing the work It is not particularly limited as long as it can exhibit sufficient adhesion to the work).

Examples of adhesives constituting the adhesive layer in the present embodiment include acrylic adhesives, rubber adhesives, silicone adhesives, urethane adhesives, polyester adhesives, polyvinyl ether adhesives, and the like. be done. Among these, it is preferable to use an acrylic pressure-sensitive adhesive from the viewpoint that it is easy to adjust the tin atom content within the range described above and that it is easy to exhibit the desired adhesive strength.

In addition, in the pressure-sensitive adhesive layer of the present embodiment, tin alone and/or a tin-containing compound may be added to the pressure-sensitive adhesive constituting the layer to achieve the aforementioned tin atom content. Alternatively, the aforementioned tin atom content may be achieved by using a tin-containing compound (in particular, a tin-containing catalyst to be described later) as one of the materials of the pressure-sensitive adhesive layer.

The adhesive that constitutes the adhesive layer in the present embodiment may be an adhesive that does not have active energy ray-curable properties, but an adhesive that has active energy ray-curable properties (hereinafter referred to as "active energy ray-curable adhesive It may be referred to as "agent".) is preferred. Since the pressure-sensitive adhesive layer is composed of an active energy ray-curable pressure-sensitive adhesive, the pressure-sensitive adhesive layer is cured by the irradiation of the active energy ray, and the adhesive force of the work processing sheet to the adherend can be easily reduced. can be done. In particular, by irradiating the active energy ray, it becomes possible to easily separate the work after processing from the work processing sheet.

The active energy ray-curable pressure-sensitive adhesive that constitutes the pressure-sensitive adhesive layer may be mainly composed of a polymer having active energy ray-curable properties, or may be a non-active energy ray-curable polymer (active energy ray-curable polymer having no active energy ray-curable group) and a monomer and/or oligomer having at least one active energy ray-curable group. Moreover, it may be a mixture of a polymer having active energy ray-curable properties and a non-active energy ray-curable polymer, or a polymer having active energy ray-curable properties and at least one or more active energy ray-curable groups. It may be a mixture with monomers and/or oligomers, or a mixture of the three.

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

The active energy ray-curable polymer is a (meth)acrylic acid ester (co)polymer (A) (hereinafter referred to as It may be referred to as "active energy ray-curable polymer (A)"). This active energy ray-curable polymer (A) comprises an acrylic copolymer (a1) having a functional group-containing monomer unit and an unsaturated group-containing compound (a2) having a functional group that binds to the functional group. It is preferably obtained by reacting.

The acrylic copolymer (a1) preferably contains structural units derived from functional group-containing monomers and structural units derived from (meth)acrylate monomers or derivatives thereof.

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

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

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

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

The acrylic copolymer (a1) preferably contains 1% by mass or more, particularly preferably 5% by mass or more, further preferably 10% by mass or more of the structural unit derived from the functional group-containing monomer. preferably. The acrylic copolymer (a1) preferably contains 35% by mass or less, more preferably 30% by mass or less, of structural units derived from the functional group-containing monomer. When the acrylic copolymer (a1) contains the functional group-containing monomer within the above range, it becomes easy to form the desired active energy ray-curable polymer (A).

Examples of the (meth)acrylic acid ester monomer constituting the acrylic copolymer (a1) include (meth)acrylic acid alkyl esters in which the alkyl group has 1 to 20 carbon atoms, and, for example, an alicyclic A monomer having a structure (alicyclic structure-containing monomer) is preferably used.

Examples of the (meth)acrylic acid alkyl esters include (meth)acrylic acid alkyl esters in which the alkyl group has 1 to 18 carbon atoms, such as methyl (meth)acrylate, ethyl (meth)acrylate, and (meth)acrylic acid. Propyl 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.

Examples of alicyclic structure-containing monomers include cyclohexyl (meth)acrylate, dicyclopentanyl (meth)acrylate, adamantyl (meth)acrylate, isobornyl (meth)acrylate, and dicyclopentenyl (meth)acrylate. , dicyclopentenyloxyethyl (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.

The acrylic copolymer (a1) preferably contains 50% by mass or more, particularly preferably 60% by mass or more, and further preferably contains 70% by mass or more of structural units derived from (meth)acrylate monomers or derivatives thereof. It is preferable to contain more than mass %. Further, the acrylic copolymer (a1) preferably contains 99% by mass or less, particularly 95% by mass or less, of structural units derived from (meth)acrylic acid ester monomers or derivatives thereof. Preferably, it is contained in an amount of 90% by mass or less.

The acrylic copolymer (a1) can be obtained by conventionally copolymerizing a functional group-containing monomer as described above and a (meth)acrylic acid ester monomer or derivative thereof. Dimethylacrylamide, vinyl formate, vinyl acetate, styrene, and the like may be copolymerized.

The acrylic copolymer (a1) having a functional group-containing monomer unit is reacted with an unsaturated group-containing compound (a2) having a functional group that binds to the functional group to obtain an active energy ray-curable polymer ( A) is obtained.

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

The unsaturated group-containing compound (a2) contains at least 1, preferably 1 to 6, more preferably 1 to 4 active energy ray-polymerizable carbon-carbon double bonds per molecule. is Specific examples of such unsaturated group-containing compounds (a2) include, for example, 2-methacryloyloxyethyl isocyanate, meta-isopropenyl-α,α-dimethylbenzyl isocyanate, methacryloyl isocyanate, allyl isocyanate, 1,1-( Bisacryloyloxymethyl)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 hydroxyethyl (meth) Acryloyl monoisocyanate compound obtained by reaction with 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 unsaturated group-containing compound (a2) is preferably 50 mol% or more, particularly preferably 60 mol% or more, and still more preferably 70 mol%, based on the number of moles of functional group-containing monomers in the acrylic copolymer (a1). % or more. In addition, the unsaturated group-containing compound (a2) is preferably 95 mol% or less, particularly preferably 93 mol% or less, and more preferably It is used in a proportion of 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 the pressure-sensitive adhesive of the present embodiment, it is preferable to use a tin-containing catalyst as a catalyst for promoting the reaction between the acrylic copolymer (a1) and the unsaturated group-containing compound (a2). By using a tin-containing catalyst, the reaction between the acrylic copolymer (a1) and the unsaturated group-containing compound (a2) proceeds effectively, making it easier to form a pressure-sensitive adhesive having desired performance, It becomes easy to adjust the tin atom content in the obtained pressure-sensitive adhesive layer to the range described above.

Examples of the tin-containing catalyst include organic tin compounds such as dibutyltin dilaurate, trimethyltin hydroxide and tetra-n-butyltin; organic acid tin compounds such as tin octenoate and tin octylate; stannous chloride; Examples thereof include tin salts such as stannic tin, among which dibutyltin dilaurate is preferred. These may be used alone or in combination of two or more.

The amount of the tin-containing catalyst is preferably 0.010% by mass or more, particularly 0.015% by mass or more, based on the total amount of monomers constituting the acrylic copolymer (a1). is preferable, and more preferably 0.02% by mass or more. Further, the amount to be blended is preferably 0.12% by mass or less, particularly preferably 0.10% by mass or less, based on the total amount of monomers constituting the acrylic copolymer (a1). , and more preferably 0.08% by mass or less.
When the amount of the tin-containing catalyst is within the above range, the content of tin atoms in the pressure-sensitive adhesive layer is adjusted within the above-described range while enabling good formation of the active energy ray-curable polymer (A). becomes easier.

The weight average molecular weight (Mw) of the active energy ray-curable polymer (A) obtained as described above is preferably 10,000 or more, particularly preferably 150,000 or more, further preferably 200,000 or more. is preferred. Also, the weight average molecular weight (Mw) is preferably 1,500,000 or less, particularly preferably 1,000,000 or less.

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

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

Examples of such active energy ray-curable monomers and/or oligomers (B) include monofunctional acrylic acid esters 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 polyfunctional acrylates such as glycol di(meth)acrylate and dimethyloltricyclodecane di(meth)acrylate; polyester oligo(meth)acrylate; polyurethane oligo(meth)acrylate;

When blending the active energy ray-curable monomer and/or oligomer (B) with the active energy ray-curable polymer (A), the active energy ray-curable monomer and/or 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, relative to 100 parts by mass of the active energy ray-curable polymer (A). 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 active energy ray-curable polymer (A).

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

Specific examples of the photopolymerization initiator (C) include benzophenone, acetophenone, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzoin benzoic acid, methyl benzoin benzoate, benzoin dimethyl ketal, 2,4-diethylthioxanthone, 1-hydroxycyclohexylphenyl ketone, benzyldiphenylsulfide, tetramethylthiuram monosulfide, azobisisobutyronitrile, benzyl, dibenzyl, diacetyl, β-chloranthraquinone, (2,4, 6-trimethylbenzyldiphenyl)phosphine oxide, 2-benzothiazole-N,N-diethyldithiocarbamate, oligo{2-hydroxy-2-methyl-1-[4-(1-propenyl)phenyl]propanone}, 2, 2-dimethoxy-1,2-diphenylethan-1-one and the like. These may be used independently and may use 2 or more types together.

The photopolymerization initiator (C) is an active energy ray-curable polymer (A) (when an active energy ray-curable monomer and/or oligomer (B) is blended, the active energy ray-curable polymer (A ) and the active energy ray-curable monomer and/or oligomer (B) in an amount of 0.1 parts by mass or more, particularly 0.5 parts by mass or more per 100 parts by mass of the total amount of 100 parts by mass) preferable. In addition, the photopolymerization initiator (C) is an active energy ray-curable polymer (A) (when an active energy ray-curable monomer and/or oligomer (B) is blended, an active energy ray-curable polymer It is preferably used in an amount of 10 parts by mass or less, particularly 6 parts by mass or less per 100 parts by mass of the total amount of (A) and the active energy ray-curable monomer and/or oligomer (B) (100 parts by mass).

In addition to the above components, the active energy ray-curable pressure-sensitive adhesive may optionally contain other components. Other components include, for example, a non-active energy ray-curable polymer component or oligomer component (D), a cross-linking agent (E), and the like.

Examples of the non-active energy ray-curable polymer component or oligomer component (D) include polyacrylates, polyesters, polyurethanes, polycarbonates, polyolefins, etc., and polymers having a weight average molecular weight (Mw) of 3,000 to 2,500,000 or Oligomers are preferred. By incorporating the component (D) into the active energy ray-curable pressure-sensitive adhesive, it is possible to improve the adhesiveness and peelability before curing, the strength after curing, the adhesion to other layers, storage stability, and the like. The 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).

As the cross-linking agent (E), a polyfunctional compound having reactivity with the functional groups 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, Reactive phenol resin etc. can be mentioned. Among these, isocyanate-based compounds are preferable, and hexamethylene diisocyanate (HMDI) compounds are particularly preferable, from the viewpoint of easily improving the adhesion of the pressure-sensitive adhesive layer to the substrate.

The amount of the cross-linking agent (E) compounded is preferably 0.01 parts by mass or more, particularly 0.03 parts by mass or more, relative to 100 parts by mass of the active energy ray-curable polymer (A). It is preferably 0.04 parts by mass or more. Further, the amount of the cross-linking agent (E) is preferably 8 parts by mass or less, particularly preferably 5 parts by mass or less, relative to 100 parts by mass of the active energy ray-curable polymer (A). Furthermore, it is preferably 3.5 parts by mass or less.

Next, when the active energy ray-curable pressure-sensitive adhesive is mainly composed of a mixture of a non-active energy ray-curable polymer component and a monomer and/or oligomer having at least one or more active energy ray-curable groups, It is explained below.

As the non-active energy ray-curable polymer component, for example, the same component as the acrylic copolymer (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 monomers and/or oligomers as those for component (B) can be selected. The blending ratio of the non-active energy ray-curable polymer component and the monomer and/or oligomer having at least one or more active energy ray-curable groups is at least 1 per 100 parts by mass of the non-active energy ray-curable polymer component. The monomer and/or oligomer having one or more active energy ray-curable groups is preferably 1 part by mass or more, particularly preferably 60 parts by mass or more. In addition, the compounding ratio is preferably 200 parts by mass or less of monomers and/or oligomers having at least one active energy ray-curable group per 100 parts by mass of the non-active energy ray-curable polymer component, In particular, it is preferably 160 parts by mass or less.

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

Although the thickness of the pressure-sensitive adhesive layer can be appropriately set according to the method of using the work processing sheet, it is usually preferably 3 μm or more, particularly preferably 5 μm or more. Moreover, the thickness is preferably 50 μm or less, particularly preferably 40 μm or less.

(3) Release sheet In the work processing sheet according to the present embodiment, even if a release sheet is laminated on the surface of the adhesive layer for the purpose of protecting the adhesive surface until the adhesive surface is attached to the work. good. 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 plastic films 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, or the like can be used, and among these, a silicone-based release agent is preferable because it is inexpensive and provides stable performance. Although the thickness of the release sheet is not particularly limited, it is usually 20 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 In the work processing sheet according to the present embodiment, the surface resistivity of the surface (adhesive surface) of the pressure-sensitive adhesive layer opposite to the substrate is 1×10 ¹³ Ω/□ or less. is preferably 1×10 ¹⁰ Ω/□ or less, and more preferably 1×10 ⁶ Ω/□ or less. When the adhesive surface exhibits the surface resistivity described above, the work processing sheet can easily exhibit excellent antistatic properties. The lower limit of the surface resistivity is not particularly limited, and may be, for example, 1×10 ⁴ Ω/□ or more, particularly 1×10 ⁵ Ω/□ or more. The surface resistivity was measured at an applied voltage of 100 V using a device such as DIGITAL ELECTROMETER (manufactured by ADVANTEST).

3. Method for manufacturing a work processing sheet The method for manufacturing a work processing sheet according to the present embodiment is not particularly limited. It is preferable to obtain a work processing sheet by laminating one side of the base material on the surface of . When using the substrate 11b having the organic conductive film 112 on only one side of the base film 111, the pressure-sensitive adhesive layer 12 may be laminated on either side of the substrate 11b.

Formation of the adhesive layer mentioned above can be performed by a well-known method. For example, a coating liquid containing an adhesive composition for forming an adhesive layer and optionally a solvent or dispersion medium is prepared. Then, the coating liquid is applied to the peelable surface of the release sheet (hereinafter sometimes referred to as “release surface”). Subsequently, by drying the obtained coating film, a pressure-sensitive adhesive layer can be formed.

The application of the coating liquid described above can be performed by a known method, such as bar coating, knife coating, roll coating, blade coating, die coating, gravure coating, and the like. The properties of the coating liquid are not particularly limited as long as the coating liquid can be applied, and may contain components for forming the pressure-sensitive adhesive layer as a solute or dispersoid in some cases. . Moreover, the release sheet may be released as a process material, or may protect the pressure-sensitive adhesive layer until it is attached to an adherend.

When the pressure-sensitive adhesive composition for forming the pressure-sensitive adhesive layer contains the above-described cross-linking agent, the drying conditions (temperature, time, etc.) described above may be changed, or the heat treatment may be separately provided. It is preferable to promote a cross-linking reaction between the polymer component in the film and the cross-linking agent to form a cross-linked structure with a desired existence density in the pressure-sensitive adhesive layer. Furthermore, in order to allow the cross-linking reaction described above to proceed sufficiently, after bonding the pressure-sensitive adhesive layer and the base material together, curing may be performed, for example, by allowing the adhesive layer to stand in an environment of 23° C. and a relative humidity of 50% for several days. .

4. Method of Using Work Processing Sheet The work processing sheet according to the present embodiment can be used for processing a work. 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. Examples of processing at this time include back grinding of semiconductor wafers and glass plates, dicing of semiconductor wafers and glass plates, expansion of semiconductor chips and glass chips, and pickup of semiconductor chips and glass chips.

Here, when the work processing sheet according to the present embodiment includes the base material 11a, 11b including the organic conductive film 112 or the base material 11c containing the antistatic agent, the work processing sheets 1A, 1B, 1C are transported. Electrification is effectively suppressed during time and use. As a result, it is possible to effectively suppress damage to the workpiece, malfunction of the processing device, and the like.

After finishing the machining of the workpiece on the workpiece machining sheet, the workpiece can be separated from the workpiece machining sheet. For example, after dicing a semiconductor wafer or a glass plate as a work on a work processing sheet and singulating it into a plurality of semiconductor chips, the work processing sheet is expanded as necessary, and from the work processing sheet Semiconductor chips and glass chips are individually picked up.

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.

Here, when the adhesive layer in the present embodiment is composed of an active energy ray-curable adhesive, the adhesive layer is cured by irradiating the adhesive layer with an active energy ray to cure the adhesive layer. and the adhesion of the workpiece can be reduced. Thereby, when picking up a semiconductor chip or a glass chip, it is possible to easily pick up the work from the work processing sheet.

In the work processing sheet according to the present embodiment, the content of tin atoms in the adhesive layer is within the range described above. It is possible to suppress the occurrence of peeling at the interface with. Thereby, it is possible to suppress adhesion of the adhesive constituting the adhesive layer to the surface of the picked-up workpiece. That is, it is possible to suppress the occurrence of adhesive residue on the work.

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 embodiments 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.

(1) Preparation of adhesive composition 52 parts by weight of 2-ethylhexyl acrylate, 20 parts by weight of methyl methacrylate, 28 parts by weight of 2-hydroxyethyl acrylate, and 0.1% azo with respect to the total amount of these monomers After mixing with bisisobutyronitrile (polymerization initiator) in ethyl acetate, the mixture was reacted at 60° C. for 24 hours to obtain a solution containing an acrylic copolymer (solid concentration: 40 mass %). 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 90 mol% with respect to 2-hydroxyethyl acrylate constituting the acrylic copolymer, and a tin-containing catalyst is added. Dibutyltin dilaurate (DBTDL) as was added in an amount of 0.02% by weight based on the total amount of monomers mentioned above. After that, a reaction was carried out at 50° C. for 24 hours to obtain a (meth)acrylic acid ester polymer (active energy ray-curable polymer) having active energy ray-curable groups introduced into side chains. When the weight average molecular weight of the active energy ray-curable polymer was measured by the method described later, it was 500,000.

100 parts by mass of the obtained active energy ray-curable polymer (in terms of solid content, hereinafter the same), and 0.3 parts of 1-hydroxycyclohexylphenyl ketone (manufactured by BASF, product name "Omnilad 184") as a photopolymerization initiator. Parts by mass and 2 parts by mass of a hexamethylene diisocyanate trimer adduct of trimethylolpropane as a cross-linking agent (manufactured by Tosoh Corporation, product name "Coronate HL") are mixed in a solvent to obtain a coating liquid of the pressure-sensitive adhesive composition. (solid content concentration of 25% by mass) was obtained.

When a pressure-sensitive adhesive layer is formed as described below using the coating solution of the pressure-sensitive adhesive composition, the tin atom content in the resulting pressure-sensitive adhesive layer is calculated to be 0.0027% by mass.

(2) Formation of adhesive layer The release surface of a release sheet (manufactured by Lintec, product name “SP-PET3801”) consisting of a polyethylene terephthalate (PET) film with a thickness of 38 μm and a silicone-based release agent layer formed on one side thereof. A coating liquid of the adhesive composition was applied using a comma coater and dried at 90° C. for 1 minute to form an adhesive layer having a thickness of 5 μm on the release sheet.

(3) Preparation of base material An emulsion containing a polypyrrole-based conductive polymer as a conductive material, obtained by emulsion polymerization of a pyrrole monomer, is added to a butylated melamine resin (manufactured by DIC Corporation, 2 parts by mass of 100 parts by mass of a polypyrrole-based conductive polymer was added and thoroughly mixed to obtain a coating liquid for an organic conductive film.

One side of an 80 μm thick ethylene-methacrylic acid copolymer (EMAA) film was subjected to corona irradiation. Then, the coating liquid for the organic conductive film obtained as described above was applied to the corona-irradiated surface of the EMAA film, and dried by heating to form an organic conductive film having a thickness of 50 nm. Further, the other surface of the EMAA film was also subjected to corona irradiation in the same manner as described above, and then an organic conductive film having a thickness of 50 nm was formed. As a result, a substrate having organic conductive films formed on both sides of the EMAA film was obtained.

The surface resistivity of both surfaces of this base material was measured using a DIGITAL ELECTROMETER (manufactured by ADVANTEST) at an applied voltage of 100 V and found to be 1.5×10 ⁶ Ω/□. This value is very small compared to the general surface resistivity of PET film alone (1×10 ¹⁵ to 1×10 ¹⁶ Ω/□). Therefore, it is expected that the work processing sheet obtained using the base material produced as described above can exhibit excellent antistatic properties.

(4) Production of work processing sheet After bonding the surface of the pressure-sensitive adhesive layer formed in the above step (2) opposite to the release sheet to one surface of the base material obtained in the above step (3), It was stored under an environment of 23°C and 50% for one week. As a result, a work processing sheet was obtained in which the release sheet, the pressure-sensitive adhesive layer, and the base material having the organic conductive films on both sides were laminated in this order. The content of tin atoms in the adhesive layer of the work processing sheet is 0.0027% by mass, as described above.

The weight average molecular weight (Mw) of the acrylic copolymer and the active energy ray-curable polymer described above is measured using gel permeation chromatography (GPC) under the following conditions (GPC measurement) and converted to standard polystyrene. is the weight average molecular weight of
<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 super HM-H
TSK gel super H2000
・Measurement solvent: tetrahydrofuran ・Measurement temperature: 40°C

[Examples 2-6 and Comparative Examples 1-2]
The composition of the active energy ray-curable polymer is changed as shown in Table 1, and a tin-containing catalyst is used so that the content of tin atoms in the pressure-sensitive adhesive layer formed is as shown in Table 1. A work processing sheet was produced in the same manner as in Example 1, except that the amount was adjusted.

[Example 7]
A work processing sheet was produced in the same manner as in Example 1, except that a polypropylene film having a thickness of 80 μm was used as the base material. The surface resistivity of both surfaces of the base material was measured with a DIGITAL ELECTROMETER (manufactured by ADVANTEST) at an applied voltage of 100 V and found to be 1.8×10 ¹⁵ Ω/□.

[Example 8]
A work processing sheet was produced in the same manner as in Example 1, except that a polybutylene terephthalate film having a thickness of 80 μm was used as the base material. The surface resistivity of both surfaces of the base material was measured using a DIGITAL ELECTROMETER (manufactured by ADVANTEST) at an applied voltage of 100 V and found to be 2.4×10 ¹⁵ Ω/□.

[Example 9]
After kneading 100 parts by weight of polypropylene and 5 parts by weight of a polyolefin block polymer (manufactured by Sanyo Chemical Industries, Ltd., product name “Pelectron PVL”), which is a high-molecular-type antistatic agent, with a twin-screw kneader, the sheet is formed with an extruder. to obtain an antistatic agent-containing polypropylene film having a thickness of 80 μm. A work processing sheet was produced in the same manner as in Example 1, except that the film was used as a base material. The surface resistivity of both surfaces of the base material was measured with a DIGITAL ELECTROMETER (manufactured by ADVANTEST) at an applied voltage of 100 V and found to be 2.3×10 ¹⁰ Ω/□.

[Test Example 1] (Evaluation of pick-up property)
A #2000 polished surface of a silicon wafer (size 8 inches, thickness 350 μm) was printed using a laser printer (manufactured by Keyence Corporation, product name “MD-S9910A”). As a result, grooves having a width of about 50 μm and a depth of about 15 μm were formed on the polished surface in cross-sectional view.

Subsequently, the adhesive surface exposed by peeling off the release sheet from the work processing sheets produced in Examples and Comparative Examples was applied to the polished surface after the laser printing using a 2 kg rubber roller, and left for 20 minutes. did.

Then, using a dicing machine (manufactured by Disco, product name "Full Auto Dicer DF636"), the silicon wafer was diced under the following dicing conditions, thereby singulating the silicon wafer into chips having a size of 5 mm × 5 mm. .
Dicing conditions Cutting method: single cut Blade: manufactured by Disco, product name "SD3000-N1-90EC"
Blade rotation speed: 35000rpm
Cutting speed: 50mm/sec
Blade height: 20 μm as the depth of cut into the substrate

After dicing, the pressure-sensitive adhesive layer was irradiated with ultraviolet light from the substrate side surface of the work processing sheet (light amount: 200 mJ/cm ² ). Then, using a die bonder (manufactured by Canon Machinery, product name "BESTEM-D02"), the resulting chip was picked up from the work processing sheet. At this time, 10 chips were picked up, and the pick-up property was evaluated as "good" when the amount of push-up at the time of successful pickup was 300 μm or less for all the chips. On the other hand, when there was a chip whose thrust amount exceeded 300 μm or when there was a chip that could not be picked up, the pick-up property was evaluated as “×”. Table 1 shows the results.

[Test Example 2] (Evaluation of adhesive residue)
With respect to the work processing sheet evaluated as "good" in pick-up property in Test Example 1, the presence or absence of adhesive adhesion (adhesive residue) on the printed portion of the 10 picked-up chips was checked. Then, the ratio (%) of chips with adhesive residue confirmed to 10 chips was calculated. The results are shown in Table 1.

Details of abbreviations and the like in Table 1 are as follows.
EMAA: ethylene-methacrylic acid copolymer PP: polypropylene PBT: polybutylene terephthalate 2EHA: 2-ethylhexyl acrylate MMA: methyl methacrylate HEA: 2-hydroxyethyl acrylate MOI: 2-methacryloyloxyethyl isocyanate VAc: vinyl acetate BA : n-butyl acrylate

As can be seen from Table 1, when the work processing sheets obtained in Examples were used, no adhesive residue occurred.

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

DESCRIPTION OF SYMBOLS 1A, 1B, 1C... Sheet for work processing 11a, 11b, 11c... Base material 111, 111'... Base film 112... Organic conductive film 12... Adhesive layer

Claims (7)

A work processing sheet comprising a substrate and an adhesive layer laminated on one side of the substrate,
A work processing sheet, wherein the content of tin atoms in the pressure-sensitive adhesive layer is 0.002% by mass or more and 0.015% by mass or less. 2. The work processing sheet according to claim 1, wherein the adhesive layer comprises an active energy ray-curable adhesive. 3. The work processing sheet according to claim 2, wherein the active energy ray-curable adhesive contains an active energy ray-curable polymer and a tin-containing catalyst containing tin atoms. The active energy ray-curable polymer is a (meth)acrylic acid ester polymer having an active energy ray-curable group introduced into a side chain,
The (meth)acrylic acid ester polymer comprises an acrylic copolymer having functional group-containing monomer units and an unsaturated group-containing compound having a functional group that binds to the functional group. 4. The work processing sheet according to claim 3, wherein the work processing sheet is obtained by reacting with. The work processing according to any one of claims 1 to 4, wherein the surface resistivity of the surface of the base material on which the adhesive layer is laminated is 1 × 10 ¹⁰ Ω/□ or less. sheet for. The work processing sheet according to any one of claims 1 to 5, wherein the base material has an organic conductive film on the side on which the pressure-sensitive adhesive layer is laminated. The work processing sheet according to any one of claims 1 to 6, which is used for dicing.

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