WO2013146707A1

WO2013146707A1 - Heat releasable adhesive sheet for cutting electronic component, and method for machining electronic component

Info

Publication number: WO2013146707A1
Application number: PCT/JP2013/058637
Authority: WO
Inventors: 高正平山; 下川　大輔; 有満　幸生
Original assignee: 日東電工株式会社
Priority date: 2012-03-27
Filing date: 2013-03-25
Publication date: 2013-10-03
Also published as: CN104185665A; JP6000595B2; TW201348393A; JP2013203800A; KR102022140B1; TWI586785B; KR20140142243A; CN104185665B

Abstract

A conventional energy beam curable heat releasable adhesive sheet does not have sufficient adhesion between the substrate and the cured energy beam curable elastic layer, and there are cases where partial peeling (anchor fracturing) occurs between the energy beam curable elastic layer and the substrate, and cases where adhesive remains on the adherent. In order to resolve these issues, provided is a heat releasable adhesive sheet having a heat releasable adhesive layer containing heat expanding microscopic spheres, the heat releasable adhesive layer being provided to one surface of a substrate, wherein an energy beam curable elastic layer is placed on the other surface with an organic coating layer interposed therebetween.

Description

Heat-peelable pressure-sensitive adhesive sheet for electronic component cutting and electronic component processing method

The present invention relates to a heat-peelable pressure-sensitive adhesive sheet that can be easily peeled off from an adherend by reducing the adhesive force by heat treatment, and is suitable for a processing step to an electronic component or the like.
In addition, as an industrial application field, the present invention relates to processing of electronic parts (for example, semiconductor wafers, multilayer ceramic parts, film-like semiconductor parts), etc. (for polishing, dicing, circuit formation, etc.).

The manufacturing process of electronic parts such as multilayer ceramic capacitors, semiconductor wafers, and film-like semiconductors includes a process of processing the electronic parts in a state of being attached to an adhesive sheet or the like (for example, a substrate dicing process). As the pressure-sensitive adhesive sheet, many heat-peelable pressure-sensitive adhesive sheets that can be peeled off by heat treatment are used. Since the heat-peelable pressure-sensitive adhesive sheet has a heat-expandable pressure-sensitive adhesive layer containing heat-peelable microspheres, an electronic component (adhered body) is adhered and fixed to the surface of the heat-expandable pressure-sensitive adhesive layer. Thus, the adherend can be subjected to desired processing, and after processing, the heat-expandable microspheres in the heat-expandable adhesive layer are expanded by heating to reduce or eliminate the adhesive force. It is characterized by being easily peelable from the body.

However, when an electronic component or the like is processed using the pressure-sensitive adhesive sheet, for example, in a back grinding process included in the semiconductor wafer manufacturing process, a large surface stress is applied to the adherend in contact with the thermally expandable pressure-sensitive adhesive layer. The problem is that the uneven shape of the thermally expandable microspheres in the thermally expandable adhesive layer is transferred to the surface of the adherend, and the thickness of the adherend varies due to the transferred unevenness, resulting in a decrease in processing accuracy. There is.

In addition, in the process of pouring a liquid resin such as a silicone resin or an epoxy resin into the adherend adhered to the surface of the heat-expandable pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet or the mold having the adherend inside, and heating and curing. When the resin is cured, the irregularities of the thermally expandable microspheres are transferred to the surface of the adherend contacting the thermally expandable adhesive layer, or the irregularities of the thermally expandable microspheres partially expanded at a low temperature due to the curing temperature of the resin. There is a case to transfer.

Moreover, in order to prevent the adherend after processing or the adherend itself from warping, there is a so-called pedestal method in which a support is pasted to an adhesive sheet to which the adherend is attached. It has been adopted. For example, in the back grinding process of the semiconductor wafer, a wafer to be ground is attached to the surface of the heat-expandable double-sided pressure-sensitive adhesive sheet, and the opposite surface (for example, the substrate surface) of the heat-expandable pressure-sensitive adhesive layer is attached. A method of performing processing by bonding a pedestal wafer as a support is performed. However, in such a case, a large amount of organic contamination due to the cohesive failure of the pressure-sensitive adhesive in which the thermally expandable microspheres are thermally expanded is observed on the adherend (wafer) after heat separation, In some cases, this may cause problems in the subsequent process.
As described in Patent Document 1 for this problem, the base material is composed of a heat-expandable pressure-sensitive adhesive layer containing heat-expandable microspheres on one side, and a pressure-sensitive adhesive or an energy ray-curable pressure-sensitive adhesive on the other side. There has been known a method of easily recovering a processed adherend without damage by processing using a heat-peelable double-sided pressure-sensitive adhesive sheet provided with an adhesive layer.

Patent No. 4428908

However, the conventional energy ray curable heat-peelable pressure-sensitive adhesive sheet used in this method does not have sufficient adhesion between the cured energy ray curable elastic layer and the substrate, and the energy ray curable elastic layer Since peeling (throwing destruction) may partially occur between the materials and adhesive residue may be generated on the adherend, it is necessary to eliminate such troubles.

As a result of earnest research on the throwing and peeling of the conventional energy ray curable heat-peelable pressure-sensitive adhesive sheet, the inventors of the present invention have revealed that a method for chemically increasing the affinity between the pressure-sensitive adhesive layer and the substrate and the surface of the substrate The present inventors have newly found that the above-described throwing-off cannot be effectively prevented by a method used in a normal pressure-sensitive adhesive sheet, such as a method of forming fine irregularities on the surface to increase the contact area between the two. And the trial and error about the structure of the heat-peelable adhesive sheet which can suppress the throwing destruction about this kind of adhesive sheet effectively was repeated, and it came to completion of the following this invention.

1. A heat-peelable pressure-sensitive adhesive sheet comprising a heat-peelable pressure-sensitive adhesive layer containing thermally expandable microspheres on one surface of a base material, and energy ray-curable elasticity via an organic coating layer on the other surface A heat-peelable pressure-sensitive adhesive sheet comprising a layer.
2. 2. The heat-peelable pressure-sensitive adhesive sheet according to 1, wherein the organic coating layer is formed using polyurethane, urethane-modified vinyl acetate-vinyl chloride copolymer, polyacryl urethane, polyurethane polyester, or a precursor thereof.
3. 3. The heat-peelable pressure-sensitive adhesive sheet according to 1 or 2, wherein the energy ray-curable elastic layer has a thickness of 3 to 300 μm.
4). A heat-peelable pressure-sensitive adhesive sheet comprising a heat-peelable pressure-sensitive adhesive layer containing thermally expandable microspheres on one surface of a substrate, wherein the heat-peelable pressure-sensitive adhesive layer is an energy ray-curable elastic layer or organic A heat-peelable pressure-sensitive adhesive sheet, which is provided via a coating layer and an energy ray-curable elastic layer, and has an energy ray-curable elastic layer disposed on the other surface via an organic coating layer.
5. 5. The heat-peelable pressure-sensitive adhesive sheet according to 4, wherein the organic coating layer is formed using polyurethane, urethane-modified vinyl acetate-vinyl chloride copolymer, polyacryl urethane, polyurethane polyester, or a precursor thereof.
6). 6. The heat-peelable pressure-sensitive adhesive sheet according to 4 or 5, wherein the energy ray-curable elastic layer has a thickness of 3 to 300 μm.
7. A method for processing a workpiece, wherein the workpiece is processed in a state in which the workpiece is attached to the heat-peelable pressure-sensitive adhesive sheet according to any one of items 7 to 6.

According to the present invention, partial delamination (throwing destruction) between the energy beam curable elastic layer and the substrate due to insufficient adhesion between the energy beam curable elastic layer and the substrate after curing. ), It is possible to prevent occurrence of adhesive residue on the adherend.

Schematic showing an example of the heat-peelable pressure-sensitive adhesive sheet of the present invention Schematic showing another example of the heat-peelable pressure-sensitive adhesive sheet of the present invention Schematic which shows the process of processing an electronic component using the heat peeling type adhesive sheet of this invention Schematic which shows the process of processing an electronic component using the heat peeling type adhesive sheet of this invention Schematic showing another example of the heat-peelable pressure-sensitive adhesive sheet of the present invention Schematic which shows the process of processing an electronic component using the heat peeling type adhesive sheet of this invention

DESCRIPTION OF SYMBOLS 1 Base material 2 Organic coating layer 3 Energy ray hardening-type elastic layer 4 Thermally peelable adhesive layer 5 Separator 6 Separator 7 Work piece (to-be-cut object)
8 Energy line 9 Cutting line 10 Support

As a result of diligent research to solve the above problems, in response to these problems, first, an organic coating layer is provided between the base material and the energy ray curable elastic layer to thereby provide the energy ray curable elastic layer. It has been found that it is possible to prevent adhesive residue from being produced at the time of peeling by improving the adhesion to the substrate.

Hereinafter, the structure of the heat-peelable pressure-sensitive adhesive sheet of the present invention will be described with reference to FIG.
As described above, the heat-peelable sheet of the present invention is a heat-peelable pressure-sensitive adhesive sheet in which a heat-peelable pressure-sensitive adhesive layer containing thermally expandable microspheres is provided on one surface of a substrate, The heat-peelable pressure-sensitive adhesive sheet is characterized in that an energy ray-curable elastic layer that is cured via an organic coating layer is disposed on the surface.
The energy ray-curable elastic layer of the heat-peelable pressure-sensitive adhesive sheet has adhesiveness, the energy ray-curable elastic layer adheres to a workpiece such as a device, and the heat-peelable pressure-sensitive adhesive layer is attached to a support or the like. By being bonded, the workpiece is fixed on the support by the heat-peelable pressure-sensitive adhesive sheet of the present invention. Thereafter, the workpiece is subjected to one or more kinds of arbitrary processing such as various mechanical processing such as cutting and polishing, physical processing such as light irradiation, and chemical processing such as exposure to a specific gas atmosphere. Apply.
Subsequently, the heat-peelable pressure-sensitive adhesive sheet of the present invention is heated to foam thermally expandable microspheres, whereby the workpiece and the heat-peelable pressure-sensitive adhesive sheet of the present invention are peeled from the support. Next, the workpiece is peeled from the energy ray-curable elastic layer of the heat-peelable pressure-sensitive adhesive sheet of the present invention.
By such a method, the heat-peelable pressure-sensitive adhesive sheet of the present invention is used.

Next, each layer constituting the heat-peelable pressure-sensitive adhesive sheet of the present invention will be described.
[Base material]
The base material 1 serves as a support base for the organic coating layer 2, the energy ray curable elastic layer 3, the heat-peelable pressure-sensitive adhesive layer 4 and the like, and the mechanical properties are not impaired by the heat treatment of the heat-peelable pressure-sensitive adhesive layer 4. Those having a degree of heat resistance are used.
Examples of such a substrate 1 include, but are not limited to, plastic films and sheets such as polyester, olefin resin, and polyvinyl chloride.
The substrate 1 preferably has a cutting property with respect to cutting means such as a cutter used when cutting the workpiece 7. In addition, when a base material having heat resistance and stretchability such as a flexible polyolefin film or sheet is used as the base material 1, if the cutting blade enters the base material halfway during the cutting process of the workpiece 7, Since the material can be stretched, it is suitable for a cut piece collection method that requires a gap between the cut pieces.

Further, when the energy beam curable elastic layer 3 is cured from the substrate 1 side, the energy beam is used so that the substrate 1 and the organic coating layer 2 (and the heat-peelable pressure-sensitive adhesive layer 4) are energy beams. It is necessary to be made of a material that can transmit a predetermined amount or more of energy rays enough to cure the curable elastic layer 3. Further, if the energy ray curable elastic layer 3 is provided on the separator 6 and is cured through the separator 6, it is necessary to make the separator 6 energy ray permeable.
The substrate 1 may be a single layer or a multilayer.

The thickness of the substrate 1 can be appropriately selected within a range that does not impair the operability and workability in each step such as bonding of the workpiece 7, cutting of the workpiece 7, peeling of the cut piece, and recovery, etc. It is 500 μm or less, preferably about 3 to 300 μm, more preferably about 5 to 250 μm.
The surface of the substrate 1 is chemically treated by conventional surface treatments such as chromic acid treatment, ozone exposure, flame exposure, high piezoelectric impact exposure, ionizing radiation treatment, etc. in order to improve adhesion and retention with adjacent layers. Alternatively, a physical treatment, a coating treatment with an undercoat (for example, an adhesive substance described later), or the like may be performed.

[Organic coating layer]
The organic coating layer 2 is used for the purpose of satisfactorily adhering to the base material 1 and preventing the energy ray curable elastic layer 3 from being thrown and destroyed after heat peeling.
Whether or not the throwing destruction occurs can be evaluated by, for example, the method described in the following examples. Since the organic coating layer 2 has a function as a primer layer and the base material 1 and the energy ray curable elastic layer 3 are more strongly bonded to each other through the organic coating layer 2, it is possible to prevent throwing destruction. When this heat-peelable pressure-sensitive adhesive sheet is used, the effect of heat-peeling is good and the adhesive peels off, that is, the adhesive residue does not occur.

As long as the organic coating layer 2 has these characteristics, any material may be used.
For example, various coating materials as shown in the literature (Plastic Hard Coat Material II, CMC Publishing, (2004)) can be used. Especially, the polymer which has urethane bonds, such as a urethane type polymer, is preferable. This is because excellent adhesion to the base material 1 and excellent anchoring properties to the energy ray curable elastic layer 3 (particularly after curing) are exhibited. In particular, polyacryl urethane and polyester polyurethane and their precursors are more preferable. These materials are practical, such as simple application and application to the substrate 1, and various industrial materials can be selected and can be obtained at low cost.

As polyacryl urethane and polyester polyurethane, any of those described in the literature (Plastic Hard Coat Material II, P17-21, CMC Publishing, (2004)) and literature (Latest Polyurethane Material and Applied Technology, CMC Publishing, (2005)) Can also be used. These are polymers composed of a reaction mixture of an isocyanate monomer and an alcoholic hydroxyl group-containing monomer (for example, a hydroxyl group-containing acrylic compound or a hydroxyl group-containing ester compound). As further components, chain extenders such as polyamines, anti-aging agents, oxidation stabilizers and the like may be included.
As the polyacryl urethane and polyester polyurethane, those prepared by reacting the above-described monomers may be used, or those commercially available or used as a binder resin for coating materials or inks and paints may be used ( Literature: Latest polyurethane materials and applied technology, P190, CMC Publishing, (2005)). Examples of such polyurethanes include “NB300” manufactured by Dainichi Seika Kogyo Co., Ltd., “Adekabon Titer (registered trademark)” manufactured by ADEKA Co., Ltd., and “Takelac® A” manufactured by Mitsui Chemicals, Inc. / Takenate (registered trademark) A ”and“ UC Sealer ”manufactured by DIC Graphics Corporation.
A dye may be added to such a polymer, and the ink may be printed on a film layer as an ink. At this time, a polyurethane-modified resin such as polyurethane-based vinyl acetate-vinyl chloride copolymer (NB300, manufactured by Dainichi Seika Kogyo Co., Ltd.) can be used, and the design of the pressure-sensitive adhesive sheet can be enhanced by such printing. It becomes possible.

Here, in particular, the reason why polyacryl urethane and polyester urethane exhibit good adhesion to the substrate 1 is that the isocyanate component contained as a monomer is a polar functional group such as a hydroxyl group or a carboxyl group present on the substrate surface. It is thought that it forms a strong bond by reacting with.
In particular, the reason why the anchoring property with the energy ray curable elastic layer 3 is improved after the energy ray curing is that the radical species generated in the vicinity of the urethane bond and the energy ray curable elastic layer 3 are generated when irradiated with ultraviolet rays or the like. It is presumed that the radical species react to form a strong bond (Reference: Structure / Physical Properties of Polyurethanes, High Functionality and Application Development, p191-194, Technical Information Association, (1999)).

The thickness of the organic coating layer 2 is not particularly limited. For example, about 0.1 to 10 μm is suitable, about 0.1 to 5 μm is preferable, and about 0.5 to 5 μm is more preferable.
If it is in the range of 0.1 to 10 μm, the adhesive residue preventing effect can be shown by exhibiting sufficient adhesion between the base material 1 and the energy ray curable elastic layer 3, and the heat release type The physical properties of the adhesive sheet are not significantly impaired.

[Energy ray curable elastic layer]
The energy ray curable elastic layer 3 is a layer having an adhesive strength that is low in adhesive strength by being cured by the energy rays 8 and that can be peeled off from the work piece after curing.
The energy ray curable elastic layer 3 contains an energy ray curable compound (or energy ray curable resin) for imparting energy ray curable properties. The energy ray curable elastic layer 3 is preferably an elastic body after irradiation with energy rays. From this point of view, the energy ray curable elastic layer 3 uses a base material (adhesive) chemically modified with an energy ray reactive functional group, or an energy ray curable compound (or energy ray curable resin). ) Is preferably composed of a composition blended in an elastic base material.
In addition, as shown in FIG. 2, on the side of the base material 1 on which the heat-peelable pressure-sensitive adhesive layer 4 is provided, an organic coating layer is sequentially disposed between the base material 1 and the heat-peelable pressure-sensitive adhesive layer 4 from the base material 1 side. 2 and the energy ray curable elastic layer 3, or when the energy ray curable elastic layer 3 is provided, the energy ray curable elastic layer 3 is the heat-peelable pressure-sensitive adhesive layer 4 in any case. Has a viscoelasticity that can relieve the unevenness of the thermally expandable microspheres.
At that time, a part of the heat-expandable microspheres contained in the heat-peelable pressure-sensitive adhesive layer 4 can be embedded in the energy ray-curable elastic layer 3 (see the enlarged view of FIG. 2). ).

Examples of the base material include natural rubber and synthetic rubber or rubber-based pressure-sensitive adhesives using them, silicone rubber or pressure-sensitive adhesives thereof, (meth) acrylic acid alkyl esters [for example, (meth) acrylic acid methyl ester, ethyl Ester, propyl ester, isopropyl ester, butyl ester, isobutyl ester, hexyl ester, octyl ester, 2-ethylhexyl ester, isooctyl ester, isodecyl ester, _C1-20 alkyl ester such as dodecyl ester, etc.] alone or in combination Combined or alkyl (meth) acrylic acid ester and other monomer [for example, monomer containing carboxyl group or acid anhydride group such as acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, maleic anhydride; (meth) Acrylic acid 2-H Hydroxyl group-containing monomers such as roxyethyl; sulfonic acid group-containing monomers such as styrene sulfonic acid; phosphate group-containing monomers such as 2-hydroxyethylacryloyl phosphate; amide group-containing monomers such as (meth) acrylamide; (meth) acrylic acid amino Amino group-containing monomers such as ethyl; alkoxy group-containing monomers such as methoxyethyl (meth) acrylate; imide group-containing monomers such as N-cyclohexylmaleimide; vinyl esters such as vinyl acetate; vinyl groups such as N-vinylpyrrolidone Heterocyclic compounds; Styrene monomers such as styrene and α-methylstyrene; Cyano group-containing monomers such as acrylonitrile; Epoxy group-containing acrylic monomers such as glycidyl (meth) acrylate; Vinyl ether monomers such as vinyl ether ], A copolymer composed of a body acrylic resin or a pressure sensitive adhesive, polyurethane resin or its adhesive, ethylene - vinyl acetate copolymers, may be used an organic viscoelastic body having an appropriate viscoelasticity. In addition, the energy ray curable elastic layer 3 and the heat-peelable pressure-sensitive adhesive layer 4 are adhered to each other by using the same or the same kind of component as the pressure-sensitive adhesive constituting the heat-peelable pressure-sensitive adhesive layer 4 described later as the base material. Can be laminated with good performance. A preferred base material includes an adhesive substance such as an acrylic adhesive. The base material may be composed of one component, or may be composed of two or more components.

Examples of the energy ray-reactive functional group used for chemical modification include functional groups having a carbon-carbon multiple bond such as acryloyl group, methacryloyl group, vinyl group, allyl group, and acetylene group. You may use these individually or in combination of 2 or more types. These functional groups can form radicals by cleavage of carbon-carbon multiple bonds upon irradiation with energy rays, and these radicals can form a crosslinking point to form a three-dimensional network structure.
Among them, the (meth) acryloyl group is preferable from the viewpoints of reactivity and workability, such as being relatively highly reactive to energy rays and being able to be selected and used in combination from various acrylic pressure-sensitive adhesives.

Thus, as a typical example of a matrix chemically modified with an energy ray-reactive functional group, a monomer containing a reactive functional group such as a hydroxyl group and / or a carboxyl group [for example, (meta Reactive functional group-containing acrylic polymer obtained by copolymerization of () 2-hydroxyethyl acrylate, (meth) acrylic acid, etc.] with (meth) acrylic acid alkyl ester reacts with the reactive functional group in the molecule. And a polymer obtained by reacting a compound having a group (isocyanate group, epoxy group, etc.) and an energy ray-reactive functional group (acryloyl group, methacryloyl group, etc.) [for example, (meth) acryloyloxyethylene isocyanate etc.]. .
The ratio of the monomer containing a reactive functional group in the reactive functional group-containing acrylic polymer is, for example, 5 to 40% by weight, preferably 10 to 30% by weight, based on the total monomers.

The amount of the compound having a group that reacts with the reactive functional group and an energy ray reactive functional group in the molecule is such that when the reactive functional group-containing acrylic polymer is reacted with the reactive functional group-containing acrylic polymer. The amount is, for example, 20 to 100 mol%, preferably 40 to 95 mol%, based on the reactive functional group (hydroxyl group, carboxyl group, etc.) in the coalescence. In addition, in order to promote (addition) reaction between the reactive functional group in the reactive functional group-containing acrylic polymer and the compound having an energy ray reactive functional group and a reactive functional group in the molecule In addition, a catalyst such as an organometallic compound such as organotin or organozirconium or an amine compound may be blended.

The energy ray-curable elastic layer 3 for curing the energy ray-curable elastic layer 3 is not particularly limited as long as it can be cured by energy rays such as visible light, ultraviolet rays, and electron beams. It is preferable that the energy beam curable elastic layer 3 is efficiently three-dimensionally reticulated. The energy ray-curable compound can be used alone or in combination of two or more.

Specific examples of the energy beam curable compound when the energy beam curable compound is blended with the base material include, for example, trimethylolpropane triacrylate, tetramethylolmethane tetraacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, Examples include pentaerythritol monohydroxypentaacrylate, dipentaerythritol hexaacrylate, 1,4-butylene glycol diacrylate, 1,6-hexanediol diacrylate, and polyethylene glycol diacrylate.

An energy ray curable resin may be used as the energy ray curable compound. Examples of the energy ray curable resin include an ester (meth) acrylate having a (meth) acryloyl group at a molecular end, a urethane (meth) acrylate, an epoxy ( Meth) acrylate, melamine (meth) acrylate, acrylic resin (meth) acrylate, thiol-ene addition type resin having an allyl group at the molecular end, photocationic polymerization type resin, cinnamoyl group-containing polymer such as polyvinyl cinnamate, diazotized Examples include amino novolak resins and acrylamide type polymers, photosensitive reactive group-containing polymers, and photosensitive reactive group-containing oligomers. Furthermore, examples of the polymer that reacts with high energy rays include epoxidized polybutadiene, unsaturated polyester, polyglycidyl methacrylate, polyacrylamide, and polyvinylsiloxane. In addition, when using energy-beam curable resin, the said base material is not necessarily required.

The amount of the energy beam curable compound is, for example, in the range of about 5 to 500 parts by weight, preferably 15 to 300 parts by weight, and more preferably about 20 to 150 parts by weight with respect to 100 parts by weight of the base material. Further, the dynamic elastic modulus of the energy ray curable elastic layer 3 after irradiation with the energy ray is 20 × 10 ⁶ to 1 × 10 ¹⁰ Pa (frequency: 1 Hz, sample: thickness 1. When the thickness is 5 mm, it is possible to achieve both excellent cutting workability and heat peelability. This storage elastic modulus can be adjusted by appropriately selecting the type and blending amount of the energy ray curable compound, the energy ray irradiation conditions, and the like.
In addition, you may use an energy beam polymerization accelerator together with an energy beam polymerization initiator as needed.

The energy ray curable elastic layer 3 includes, in addition to the above components, an energy ray polymerization initiator for curing the energy ray curable compound, and a thermal polymerization initiator for obtaining appropriate viscoelasticity before and after the energy ray curing. In addition, an appropriate additive such as a crosslinking agent, a tackifier, a vulcanizing agent, a filler, an anti-aging agent, an antioxidant, and a coloring agent can be blended as necessary.

As the energy beam polymerization initiator, a known or commonly used polymerization initiator can be appropriately selected according to the type of energy beam used.
When polymerization / curing is performed using ultraviolet rays as energy rays, a photopolymerization initiator is included for curing. The photopolymerization initiator is not particularly limited, and examples thereof include benzoin ethers such as benzoin methyl ether, benzoin isopropyl ether and 2,2-dimethoxy-1,2-diphenylethane-1-one; substituted benzoin ethers such as anisole methyl ether Substituted acetophenones such as 2,2-diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 1-hydroxy-cyclohexyl-phenyl-ketone; substituted alpha-ketols such as 2-methyl-2-hydroxypropiophenone; Aromatic sulfonyl chlorides such as 2-naphthalenesulfonyl chloride; Photoactive oximes such as 1-phenyl-1,1-propanedione-2- (o-ethoxycarbonyl) -oxime; 2,4,6-trimethylbenzoyl-diphe And acylphosphine oxides such as nyl-phosphine oxide and bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide.

The energy ray curable elastic layer 3 is based on, for example, an energy ray curable resin or a coating liquid containing a base material, an energy ray polymerizable compound, an energy ray polymerization initiator, and, if necessary, an additive, a solvent and the like. A method of coating on the material 1, a method of forming the energy ray-curable elastic layer 3 by coating the coating liquid on an appropriate separator (release paper or the like), and transferring (transferring) it onto the substrate 1. It can be formed by a conventional method.
When the energy ray curable elastic layer 3 is cured, if there is a concern about the occurrence of polymerization inhibition due to oxygen, a release-treated sheet is formed on a mixture of a urethane polymer and a radical polymerizable monomer coated on a separator. Oxygen may be cut off by putting on, or the substrate may be placed in a container filled with an inert gas to lower the oxygen concentration.
The type of energy beam and the type of lamp used by irradiation can be selected as appropriate. Low pressure lamps such as fluorescent chemical lamps, black lights and sterilization lamps, high pressure lamps such as metal halide lamps and high pressure mercury lamps, etc. Can be used. Furthermore, the irradiation amount of ultraviolet rays or the like can be arbitrarily set according to the required characteristics of the energy ray curable elastic layer.

The thickness of the energy ray curable elastic layer 3 is selected from the viewpoints of relaxing the unevenness of the thermally expandable microspheres included in the heat-peelable pressure-sensitive adhesive layer 4 and preventing vibration by a rotary blade when cutting the workpiece 7. It is about 3 to 300 μm, preferably about 10 to 150 μm, more preferably about 15 to 100 μm.

[Heat peelable adhesive layer]
The heat-peelable pressure-sensitive adhesive layer 4 contains a pressure-sensitive adhesive for imparting tackiness and a heat-expandable microsphere for imparting thermal expansibility.
The heat-peelable pressure-sensitive adhesive layer 4 is a layer that can be easily peeled off by reducing the bonding area due to foaming of thermally expandable microspheres caused by heat. Thermally expandable microspheres can be used alone or in combination of two or more.
The heat-expandable microsphere can be appropriately selected from known heat-expandable microspheres. Thermally expandable microspheres that are not microencapsulated may not be able to stably exhibit good peelability, and therefore, microencapsulated thermally expandable microspheres can be suitably used.
As shown in the enlarged view on the right side of FIG. 2, the heat-peelable pressure-sensitive adhesive sheet of FIG. 1 also has irregularities reflecting the shape of the thermally expandable microspheres contained on the surface of the heat-peelable pressure-sensitive adhesive layer 4. It is desirable to have smoothness without having.

As the adhesive material, a material having elasticity that allows foaming and / or expansion of the heat-expandable microspheres during heating and does not restrain them is used. For this reason, a conventionally well-known pressure sensitive adhesive (adhesive) etc. can be used. Examples of pressure-sensitive adhesives include, for example, rubber-based pressure-sensitive adhesives such as natural rubber and various synthetic rubbers, silicone-based pressure-sensitive adhesives, (meth) acrylic acid alkyl esters, and other copolymerizable with this ester. Examples thereof include acrylic pressure-sensitive adhesives such as copolymers with unsaturated monomers (for example, acrylic pressure-sensitive adhesives described as the base material of the energy ray-curable elastic layer 3) and the like. Further, an energy ray curable pressure sensitive adhesive can be used for the heat-peelable pressure sensitive adhesive layer 4. In that case, the shear elastic modulus of elasticity is 1 × 10 ⁵ to 5 × 10 ⁷ Pa (frequency: 1 Hz, sample: thickness) in the temperature range where the dynamic elastic modulus after irradiation with energy rays starts expansion of the thermally expandable microspheres. Good peelability can be obtained when the thickness is 1.5 mm.

As the thermally expandable microsphere, for example, a microsphere in which a substance that expands easily by gasification by heating, such as isobutane, propane, or pentane, is encapsulated in an elastic shell. The shell is usually formed of a thermoplastic material, a hot-melt material, a material that bursts due to thermal expansion, or the like. Examples of the substance forming the shell include vinylidene chloride-acrylonitrile copolymer, polyvinyl alcohol, polyvinyl butyral, polymethyl methacrylate, polyacrylonitrile, polyvinylidene chloride, and polysulfone. Thermally expandable microspheres can be produced by a conventional method such as a coacervation method or an interfacial polymerization method. As the heat-expandable microspheres, for example, commercially available products such as Matsumoto Microsphere (F-100D, manufactured by Matsumoto Yushi Seiyaku Co., Ltd.) can be used.

The average particle size of the thermally expandable microspheres is generally about 1 to 80 μm, preferably about 3 to 50 μm, more preferably 5 to 15 μm, from the viewpoint of dispersibility and thin layer formation. In addition, the thermally expandable microspheres are not ruptured until the volume expansion coefficient is 5 times or more, particularly 10 times or more in order to efficiently reduce the adhesive strength of the heat-peelable adhesive layer containing the adhesive by heat treatment. What has moderate intensity | strength is preferable. In the case of using thermally expandable microspheres that burst at a low expansion rate, or when using a thermal expansion agent that is not microencapsulated, the adhesion between the heat-peelable pressure-sensitive adhesive layer 4 and the work piece 7 The area is not sufficiently reduced, and good peelability is difficult to obtain.

The amount of the heat-expandable microspheres varies depending on the type, but for example, 10 to 200 parts by weight, preferably 20 to 125 parts by weight with respect to 100 parts by weight of the pressure-sensitive adhesive base polymer constituting the heat-peelable pressure-sensitive adhesive layer 4. About parts by weight. If it is 10 to 200 parts by weight, the adhesive strength can be sufficiently reduced after the heat treatment, and cohesive failure of the heat-peelable pressure-sensitive adhesive layer 4 or interfacial failure between the energy ray-curable elastic layer 3 and the support 10 is achieved. Will not occur.

In addition to the adhesive substance and the thermally expandable microsphere, the heat-peelable adhesive layer 4 includes a crosslinking agent (for example, an isocyanate-based crosslinking agent, an epoxy-based crosslinking agent), a tackifier (for example, a multifunctional epoxy). Compound, or isocyanate compound, aziridine compound, melamine resin, urea resin, anhydrous compound, polyamine, carboxyl group-containing polymer), plasticizer, pigment, filler, anti-aging agent, surfactant, antistatic agent, etc. Various additives may be blended.

The thickness of the heat-peelable pressure-sensitive adhesive layer 4 can be appropriately determined according to the purpose of use of the pressure-sensitive adhesive sheet or the ability to reduce the pressure-sensitive adhesive force by heating. In order to improve the workability of the workpiece 7, A thinner one is preferred. For this reason, the thickness of the heat-peelable pressure-sensitive adhesive layer 4 is 50 μm or less, preferably 25 μm or less, and more preferably 10 μm or less. If the thickness of the heat-peelable pressure-sensitive adhesive layer 4 is 50 μm or less, sufficient adhesive force for holding the workpiece 7 can be obtained. Furthermore, when pressing or shearing force is applied to the electronic component when the electronic component is processed, these forces are transmitted to the heat-peelable pressure-sensitive adhesive layer 4. Since the thickness is thin, the heat-peelable pressure-sensitive adhesive sheet of the present invention can reliably hold the electronic component against this applied force.

In addition, in order to prevent the fine cohesive failure in the adhesion interface with the adherend accompanying the uneven deformation of the heat-peelable pressure-sensitive adhesive layer 4 during the heat treatment, a pressure-sensitive adhesive layer is further provided on the heat-peelable pressure-sensitive adhesive layer 4. May be provided.
As the pressure-sensitive adhesive material of the pressure-sensitive adhesive layer, the pressure-sensitive adhesive described in the aforementioned heat-peelable pressure-sensitive adhesive layer 4 can be used. The thickness of the pressure-sensitive adhesive layer is preferably 0.1 to 8 μm, particularly 1 to 5 μm from the viewpoint of reducing or eliminating the adhesive strength with respect to the workpiece 7, and is formed by a method according to the thermally expandable pressure-sensitive adhesive layer 4. can do.

[Rubber organic elastic layer]
The heat-peelable pressure-sensitive adhesive layer 4 may be provided on the substrate 1 directly or via another layer such as a rubber-like organic elastic layer. The rubbery organic elastic layer has a function of increasing the adhesion area by causing the surface of the pressure-sensitive adhesive sheet to follow the surface shape of the adherend well when bonding the heat-peelable pressure-sensitive adhesive sheet to the adherend, A function of controlling the thermal expansion of the heat-expandable layer to a high degree (accuracy) when the pressure-sensitive adhesive sheet is peeled off from the adherend, and expanding the heat-expandable layer preferentially and uniformly in the thickness direction. And have.

Examples of the synthetic rubber or the synthetic resin having rubber elasticity include, for example, synthetic rubbers such as nitriles, dienes, and acrylics; thermoplastic elastomers such as polyolefins and polyesters; ethylene-vinyl acetate copolymers, polyurethanes, and polybutadienes. And synthetic resins having rubber elasticity such as soft polyvinyl chloride. Even if it is essentially a hard polymer such as polyvinyl chloride, rubber elasticity can be manifested in combination with compounding agents such as plasticizers and softeners. Such a composition can also be used as a constituent material of the rubbery organic elastic layer. Moreover, an adhesive substance such as an adhesive constituting an adhesive layer (or a thermally expandable adhesive layer) described later can also be used as a constituent material of the rubber-like organic elastic layer. The thickness of the rubbery organic elastic layer is generally 500 μm or less (eg, 1 to 500 μm), preferably 3 to 300 μm, and more preferably about 5 to 150 μm.

[Separator]
Separator 5 is a sheet in which a release agent layer is formed on one side of a base film as necessary, and the surface layer of the heat-peelable pressure-sensitive adhesive sheet of the present invention is protected and peeled off to be exposed before use. It is a sheet | seat used as the foundation at the time of forming the sheet | seat or the heat-peelable adhesive layer 4 to be formed.
As the separator 5, for example, a base material made of a plastic film or paper whose surface is coated with a release agent typified by a silicone resin, a long-chain alkyl acrylate resin, a fluorine resin, or the like, or nonpolarity such as polyethylene or polypropylene A low-viscosity base material made of a polymer can be used.

As the substrate film of the separator 5, known ones can be used, for example, polyetheretherketone, polyetherimide, polyarylate, polyethylene naphthalate, polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, poly Vinyl chloride film, vinyl chloride copolymer film, polyethylene terephthalate film, polybutylene terephthalate film, polyurethane film, ethylene-vinyl acetate copolymer film, ionomer resin film, ethylene- (meth) acrylic acid copolymer film, ethylene- Select from (meth) acrylic acid ester copolymer film, polystyrene film, and plastic film such as polycarbonate film It is possible.
The release agent layer that can be used is a known release agent such as a fluorinated silicone resin release agent, a fluorine resin release agent, a silicone resin release agent, a polyvinyl alcohol resin, a polypropylene resin, a long chain alkyl compound, It is a layer selected and contained according to the resin of the pressure-sensitive adhesive layer.

[Example of production of heat-peelable pressure-sensitive adhesive sheet shown in FIG. 1]
FIG. 1 is a schematic sectional view showing an example of the heat-peelable pressure-sensitive adhesive sheet of the present invention. The organic coating layer 2, the energy ray curable elastic layer 3 and the separator 6 are laminated in this order on one surface of the substrate 1, and the heat-peelable pressure-sensitive adhesive layer 4 and the separator are laminated on the other surface of the substrate 1. 5 are stacked in this order.
The organic coating layer 2 is provided on one surface of the substrate 1, and the composition before curing constituting the energy ray curable elastic layer 3 is uniformly applied thereon by any means. And when said energy ray hardening-type elastic layer 3 formed in the single side | surface of the obtained base material contains solvents other than a reactive solvent, it was set as the state from which the solvent was once removed by drying after application | coating. Later, the separator 6 is coated thereon, and the substrate 1, the organic coating layer 2, the energy ray curable pressure-sensitive adhesive layer 3, and the separator 6 are laminated.
Separately, the heat-peelable pressure-sensitive adhesive layer 4 applied and dried is formed on the prepared separator 5. Thereafter, in the state where the heat-expandable microspheres do not protrude from the surface of the heat-peelable pressure-sensitive adhesive layer 4, the surface of the heat-peelable pressure-sensitive adhesive layer 4 on the side where the energy ray curable pressure-sensitive adhesive layer 3 is not provided. The layers are laminated so as to adhere to each other. In addition, you may make it provide the organic coating layer 2 in advance on both surfaces of a base material.

The structure of the heat-peelable pressure-sensitive adhesive sheet of the present invention shown in FIG. 2 will be described below.
The material of each layer constituting the heat-peelable pressure-sensitive adhesive sheet shown in FIG. 2 is the same as the material shown in FIG.
For example, the heat-peelable pressure-sensitive adhesive layer 4 is formed by directly applying a coating liquid containing pressure-sensitive adhesives, thermally expandable microspheres, and additives, solvents, and the like onto the energy ray-curable elastic layer 3, for example. A method of pressure bonding through the separator 5, the coating liquid is applied on an appropriate separator (release paper or the like) 5 to form a heat-peelable pressure-sensitive adhesive layer 4, and this is optionally an organic coating layer on the substrate 1 2 can be performed by an appropriate method such as a method of pressure transfer (transfer) onto the energy ray curable elastic layer 3 provided via 2.

At this time, as shown in the enlarged view on the right side of FIG. 2, the heat-peelable pressure-sensitive adhesive sheet of this example also has irregularities reflecting the shape of the heat-expandable microspheres contained in the surface of the heat-peelable pressure-sensitive adhesive layer 4 It is desirable to be smooth without having any.
Therefore, even if the heat-expandable microspheres do not fit within the thickness of the heat-peelable pressure-sensitive adhesive layer 4 due to the presence of large heat-expandable microspheres, the layer of the energy beam curable elastic layer 3 It is desirable to make the surface of the heat-peelable pressure-sensitive adhesive layer 4 smooth by inserting the convex portions of the thermally expandable microspheres therein.

As described above, the separator 5 is used as a temporary support when the heat-peelable pressure-sensitive adhesive layer 4 is pressure-transferred (transferred) onto the energy ray-curable elastic layer 3 as described above. Used as a protective material for protecting the agent layer 4.

[Example of production of heat-peelable pressure-sensitive adhesive sheet shown in FIG. 2]
FIG. 2 is a schematic cross-sectional view showing another example of the heat-peelable pressure-sensitive adhesive sheet of the present invention. In this example, the organic coating layer 2, the energy ray curable elastic layer 3 and the separator 6 are laminated in this order on one surface of the substrate 1, and the organic coating layer 2 on the other surface of the substrate 1, The energy ray curable elastic layer 3, the heat-peelable pressure-sensitive adhesive layer 4, and the separator 5 are laminated in this order. This pressure-sensitive adhesive sheet is different from the pressure-sensitive adhesive sheet of FIG. 1 in that an organic coating layer 2, an energy ray-curable elastic layer 3, a heat-peelable pressure-sensitive adhesive layer 4 and a separator 5 are provided on the other surface of the substrate 1. Is different.
Immediately after laminating the base material 1, the organic coating layer 2, the energy ray curable pressure sensitive adhesive layer 3, and the separator 6 which are intermediate stages in the method for producing the heat-peelable pressure-sensitive adhesive sheet, the organic coating layer 2 of the base material 1 is still present. The organic coating layer 2 is provided on the surface not provided with, and the composition before curing constituting the energy ray-curable elastic layer 3 is uniformly applied thereon by any means. And when said energy ray hardening-type elastic layer 3 formed in the single side | surface of the obtained base material contains solvents other than a reactive solvent, it is the state by which such a solvent was removed by drying, The energy ray curable elastic layer 3 is set before being cured with energy rays. However, it may be partially cured as long as it has sufficient fluidity.
Separately, the heat-peelable pressure-sensitive adhesive layer 4 applied and dried is formed on the prepared separator 5. Depending on the thickness of the heat-peelable pressure-sensitive adhesive layer 4, the surface of the heat-peelable pressure-sensitive adhesive layer 4, that is, the surface that is not on the separator 5 side, contains thermally expandable microspheres contained in the heat-peelable pressure-sensitive adhesive layer 4. Since it is not completely embedded, a part of the thermally expandable microsphere protrudes from the surface to form a convex portion.

Specifically, the surface of the heat-peeling pressure-sensitive adhesive layer 4 formed on the separator 5 is aligned with the surface of the energy ray-curable elastic layer 3 before curing. The energy ray curable uncured type is laminated by pressing the energy ray curable elastic layer 3 and the heat-peelable pressure-sensitive adhesive layer 4 from the base material 1 and the separator 5 side. The convex portion is embedded in the elastic layer 3.
As a result, the separator 6, the energy ray curable elastic layer 3, the organic coating layer 2, the substrate 1, the organic coating layer 2, the uncured energy ray curable elastic layer 3, the heat-peelable pressure-sensitive adhesive layer 4, and the separator 5 can be obtained by laminating 5 in this order.
Further, the uncured energy beam curable elastic layer 3 is cured by irradiating the uncured energy beam curable elastic layer 3 from the substrate 1 side and / or the separator 5 side. Thus, the heat-peelable pressure-sensitive adhesive sheet of the present invention can be obtained.

In addition, in the manufacturing method of these heat-peelable pressure-sensitive adhesive sheets, the procedure for laminating each layer is not limited to these orders, and any means can be adopted as long as the object of the present invention is achieved. And when manufacturing the said 2 types of heat peeling type adhesive sheet, formation of each layer to each surface can be performed by any order.

[How to use heat-peelable adhesive sheet]
FIG. 3 is a schematic process diagram showing an example of a method for manufacturing the workpiece 7 using the heat-peelable pressure-sensitive adhesive sheet shown in FIG. 1 of the present invention. More specifically, FIG. 3 shows that the work piece 7 is pressure-bonded to the surface of the energy ray-curable elastic layer 3 of the heat-peelable pressure-sensitive adhesive sheet (with the

separators

5 and 6 peeled off) in FIG. In addition, the heat-peelable pressure-sensitive adhesive layer 4 is bonded to the support 10, and the heat-peelable pressure-sensitive adhesive sheet and the workpiece 7 are fixed to the support 10.
When the energy ray curable elastic layer 3 having sufficient adhesive strength after curing is used, the energy ray curable elastic layer 3 is cured by irradiation of the energy rays 8 and then shown in the center diagram. Next, it cut | disconnects to a predetermined dimension along the cutting line 9, and is set as a cut piece. In addition, when the thing which adhesive strength falls after hardening is used as the energy ray hardening-type elastic layer 3, irradiation of the energy ray 8 will be after a cutting process.
Next, the heat-expandable microspheres in the heat-peelable pressure-sensitive adhesive layer 4 on the support 10 are expanded and foamed by heat treatment, and the heat-peelable pressure-sensitive adhesive sheet is peeled from the support 10 together with the workpiece 7.
Next, the workpiece 7 cut as shown in the right figure is picked up, and peeled off from the energy ray-curable elastic layer 3 of the heat-peelable pressure-sensitive adhesive sheet and separated.

FIG. 4 is a schematic process diagram showing an example of a method for manufacturing the workpiece 7 using the heat-peelable pressure-sensitive adhesive sheet shown in FIG. 2 of the present invention.
Only the layer structure of the heat-peelable pressure-sensitive adhesive sheet used is different, and the method of use itself is the same as in the case of FIG. Since the heat-peelable pressure-sensitive adhesive layer 4 is formed on the organic coating layer 2 via the energy ray-curable elastic layer 3 as necessary, the surface of the heat-peelable pressure-sensitive adhesive layer 4 is particularly made of thermally expandable microspheres. There is no unevenness derived from it, and the workpiece 7 can be more accurately fixed on the support 10.

In these methods for using the heat-peelable pressure-sensitive adhesive sheet, the heat-peelable pressure-sensitive adhesive layer 4 of the energy ray-curable heat-peelable pressure-sensitive adhesive sheet and the support 10 are appropriately bonded by, for example, a rubber roller, a laminate roll, or a press device. It can be performed by a method of pressure-bonding the heat-peelable pressure-sensitive adhesive sheet with a simple pressing means. During the crimping process, if necessary, depending on the type of adhesive substance, heat the heat-expandable microspheres in a temperature range that does not expand, or apply water or an organic solvent to activate the adhesive substance. You can also

Visible light, ultraviolet light, electron beam or the like can be used as the energy beam 8. Irradiation of the energy beam 8 can be performed by an appropriate method. However, since the heat-expandable microspheres may start to expand due to the heat of irradiation of the energy rays 8, the heat-expandable microspheres are limited to irradiation for as short a time as possible, or the heat-peelable adhesive sheet is air-cooled. It is desirable to maintain a temperature at which the sphere does not begin to expand. The support 10 may be a material whose adhesive strength with the heat-peelable pressure-sensitive adhesive layer 4 decreases due to the expansion of the heat-peelable pressure-sensitive adhesive layer 4, and may be displaced due to the force involved in processing the workpiece 7. It is made of a material that does not deform and allows the energy rays 8 to pass therethrough. For example, glass or a pedestal wafer can be suitably used.

The workpiece 7 can be cut by a conventional cutting means such as dicing. For example, as shown by a cutting line 9 in FIG. Moreover, grinding etc. can also be performed as a process.
The heating conditions can be appropriately set depending on the surface state of the workpiece 7 (or the cut workpiece 7), the heat resistance, the type of the thermally expandable microsphere, the heat resistance of the adhesive sheet, the heat capacity of the workpiece 7, and the like. However, general conditions are a temperature of 350 ° C. or less and a treatment time of 30 minutes or less, and a temperature of 80 to 200 ° C. and a treatment time of about 1 second to 15 minutes are particularly preferable. Moreover, as a heating system, although a hot-air heating system, a hot plate contact system, an infrared heating system, etc. are mentioned, it is not specifically limited.

When the base material 1 of the heat-peelable pressure-sensitive adhesive sheet is stretchable, the stretching process is performed, for example, by using a conventional stretching means used when stretching the sheets two-dimensionally. Can do.

As a property common to these heat-peelable pressure-sensitive adhesive sheets, since the energy ray-curable pressure-sensitive adhesive layer 3 is provided on the substrate 1 through the organic coating layer 2, the energy-ray-curable pressure-sensitive adhesive sheet of the heat-peelable pressure-sensitive adhesive sheet is provided. After the workpiece 7 provided on the pressure-sensitive adhesive layer 3 is processed, when the workpiece 7 is peeled from the energy ray-curable pressure-sensitive adhesive layer 3, the energy ray-curable pressure-sensitive adhesive layer 3 is removed from the substrate 1. It does not peel off and cause residue on the surface of the work 7 to cause contamination.
This is because the energy ray curable pressure-sensitive adhesive layer 3 is strongly adhered to the substrate 1 by the organic coating layer 2, so that the energy ray curable pressure sensitive adhesive layer 3 causes cohesive failure when the workpiece 7 is peeled off. Because there is no.

Furthermore, according to the heat-peelable pressure-sensitive adhesive sheet shown in FIG. 4, the heat-peelable pressure-sensitive adhesive layer 4 of the heat-peelable pressure-sensitive adhesive sheet can be formed thin, and is sufficient even after the energy ray-curable elastic layer 3 is cured. When a material having a strong adhesive force is used, the energy ray curable elastic layer 3 is cured by irradiating the energy ray 8 before the cutting step, so that the adhesive layer is rolled up or adhered by a cutting blade during the cutting step. Chipping and the like associated with shaking of the agent layer can be cut to a predetermined size while being greatly reduced as compared with a conventional thermally expandable pressure-sensitive adhesive sheet.
Furthermore, since the heat-peelable pressure-sensitive adhesive layer 4 includes thermally expandable microspheres and has thermal expandability, the thermally expandable microspheres are rapidly foamed or expanded by the heat treatment after the cutting step. The volume of the heat-peelable pressure-sensitive adhesive layer 4 changes to form an uneven three-dimensional structure on the surface, and the adhesion area with respect to the support 10 and thus the adhesion strength is significantly reduced or disappears.
Thereafter, the workpiece 7 cut by a known means is picked up.

The heat-peelable pressure-sensitive adhesive sheet shown in FIG. 5 has the same structure as the heat-peelable pressure-sensitive adhesive sheet shown in FIG. 1, and the heat-peelable pressure-sensitive adhesive sheet of the present invention is not only dicing but also grinding, polishing, etching, lathe processing, resin sealing It can also be used for other processes such as stopping.

FIG. 6 shows a method of processing the surface of the workpiece 7 such as grinding.
First, the

separators

5 and 6 provided on both surfaces of the heat-peelable pressure-sensitive adhesive sheet are peeled off, the work piece 7 is adhered to the surface on the energy ray curable elastic layer 3 side, and the heat-peelable pressure-sensitive adhesive layer 4 on the opposite side. The workpiece 7 is fixed to the support 10 by the side surface, and the surface of the workpiece 7 is processed.
Thereafter, the heat-expandable microspheres contained in the heat-peelable pressure-sensitive adhesive layer 4 are expanded by heating, and the heat-peelable pressure-sensitive adhesive sheet and the workpiece 7 are peeled off from the support 10.
Further, the energy beam curable elastic layer 3 is cured by irradiation of the energy beam 8, thereby increasing the cohesive force of the energy beam curable elastic layer 3 and reducing the adhesive force with the workpiece 7.
Next, the processed object 7 is obtained by peeling the processed object 7 from the energy ray curable elastic layer 3.

In addition to the above method, when the workpiece is a foldable film, the workpiece is fixed on the support via the heat-peelable pressure-sensitive adhesive sheet of the present invention, and then the workpiece surface Then, the energy ray-curable elastic layer was cured by irradiating energy rays from the workpiece surface side or the support side to cure the workpiece. It can also peel from this energy ray hardening-type elastic layer. In that case, it is also possible to employ a method of peeling the heat-peelable pressure-sensitive adhesive sheet from the support by heating the heat-peelable pressure-sensitive adhesive layer of the heat-peelable pressure-sensitive adhesive sheet after the workpiece is peeled off.

In this way, by preventing the peeling of the energy ray curable elastic layer at the time of peeling, curing the energy ray curable elastic layer 3 by irradiation with energy rays, and significantly lowering or disappearing the adhesive strength by heat treatment, The operability and workability in the prevention of adhesive residue generation, the processing step of the workpiece 7, the peeling of the processed workpiece 7 and the recovery step are greatly improved, and the production efficiency can be greatly improved.

The energy ray curable heat-peelable pressure-sensitive adhesive sheet of the present invention can be used for applications in which the workpiece 7 is permanently bonded, but after bonding the workpiece for a predetermined period and achieving the bonding purpose, It is also suitable for applications where it is required or desired to release the adhesive state. As specific examples of such applications, in addition to fixing materials for semiconductor wafers and ceramic laminated sheets, carrier tapes for temporarily transporting parts, temporarily fixing carrier tapes for assembly of various electrical devices, electronic devices, display devices, etc. Examples thereof include a surface protective material or a masking material for the purpose of preventing contamination damage such as a material or a fixing material, a metal plate, a plastic plate, and a glass plate. In particular, in the manufacturing process of electronic components, it can be suitably used for manufacturing processes such as small or thin semiconductor chips and multilayer capacitor chips.

Next, the present invention will be described in more detail based on examples. The present invention is not limited to these examples.

Production of Substrate 1 with Organic Coating Layer A PET film of Lumirror S105 (thickness 50 μm) manufactured by Toray Industries, Inc. and subjected to corona treatment on one side was used as the substrate. On the corona-treated surface side of this substrate, an organic coating layer was applied with a gravure coater so as to have a dry film thickness of 1 to 2 μm and dried to obtain a substrate 1 with an organic coating layer. For this organic coating layer, a light blue printing ink NB300 (manufactured by Dainichi Seika Kogyo Co., Ltd.) was used. NB300 contained a polyurethane-based vinyl acetate-vinyl chloride copolymer as a binder resin, and an intensity peak considered to be urethane was confirmed by IR (infrared absorption analysis).

Production of Substrate 2 with Organic Coating Layer As a substrate, a PET film made by Toray Industries, Inc., one-sided corona treated, Lumirror S105 (thickness 50 μm) was used. On the corona-treated surface side of this substrate, an organic coating layer was applied with a gravure coater so that the dry film thickness was 1 to 2 μm and dried to obtain a substrate 2 with an organic coating layer. For this organic coating layer, printing ink NB300 (manufactured by Dainichi Seika Kogyo Co., Ltd.) containing no light blue pigment was used. NB300 contained a polyurethane-based vinyl acetate-vinyl chloride copolymer as a binder resin, and an intensity peak considered to be urethane was confirmed by IR.

Production of Substrate 3 with Organic Coating Layer As a substrate, a PET film made by Toray Industries, Inc., subjected to corona treatment on one side and Lumirror S105 (thickness 50 μm) was used. On the corona-treated surface side of this substrate, an organic coating layer was applied with a gravure coater so that the dry film thickness was 1 to 2 μm and dried to obtain a substrate 3 with an organic coating layer. In this organic coating layer, 71 parts by weight of Adekabon titer U500 (manufactured by ADEKA Co., Ltd.) as a polyurethane primer and 28 parts by weight of coronate HL (manufactured by Nippon Polyurethane Industry Co., Ltd.) as an isocyanate resin Was used.

Preparation of substrate 4 with organic coating layer 50.0 parts of t-butyl acrylate, 30.0 parts of acrylic acid, 20.0 parts of butyl acrylate as acrylic monomers, and trimethylolpropane triacrylate as polyfunctional monomer 1.0 part and 1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propan-1-one (trade names: Irgacure 2959, BASF) as a photopolymerization initiator Japan Co., Ltd.) 0.1 part, polyol as polyoxytetramethylene glycol (molecular weight 650, Mitsubishi Chemical Co., Ltd.) 73.4 part, and urethane reaction catalyst as dibutyltin dilaurate 0.05 part. While stirring, 26.6 parts of xylylene diisocyanate was added dropwise and reacted at 65 ° C. for 2 hours. A remer-acrylic monomer mixture was obtained. The amount of polyisocyanate component and polyol component used was NCO / OH (equivalent ratio) = 1.25.
The obtained urethane polymer-acrylic monomer mixture was applied onto a 38 μm thick polyethylene terephthalate film (trade name: Lumirror S10, manufactured by Toray Industries, Inc.) so that the thickness after curing was 3 to 4 μm. A PET film (thickness: 38 μm) that has been peeled is coated on top of this, and the coated PET film surface is irradiated with ultraviolet rays (illuminance: 163 mW / cm ² , light amount: 2100 mJ / cm ² ) using a high-pressure mercury lamp. And cured to obtain a polyethylene terephthalate / acrylic urethane laminate sheet.

Preparation of the base material 5 with an organic coating layer A PET film was prepared as a base material. Toray Industries, Inc., single-sided corona-treated, Lumirror S105 (thickness 38 μm) was used as this PET film. On the corona-treated surface side of this rigid film layer, an organic coating layer was applied with a gravure coater so that the dry film thickness was 1 to 2 μm and dried to obtain a substrate 5 with an organic coating layer. For this organic coating layer, a blue printing ink CVL-PR (manufactured by DIC Graphics Co., Ltd.) was used. CVL-PR contains a hydroxyl group-containing vinyl acetate-vinyl chloride copolymer as a binder resin, and IR did not confirm an intensity peak considered to be urethane.

Production of substrate 6 with organic coating layer A PET film was prepared as a substrate. Toray Industries, Inc., single-sided corona-treated, Lumirror S105 (thickness 50 μm) was used as this PET film. On the corona-treated surface side of this substrate, an organic coating layer was applied with a gravure coater so as to have a dry film thickness of 1 to 2 μm and dried to obtain a substrate 6 with an organic coating layer. For this organic coating layer, an amorphous saturated copolymerized polyester resin (trade name: Byron 200, manufactured by Toyobo Co., Ltd.) was used.

Production of energy ray curable pressure-sensitive adhesive layer 1 2-ethylhexyl acrylate: morpholyl acrylate: 2-hydroxyethyl acrylate = 75: 25: 20 (molar ratio) 100 parts by weight of a mixture and 0.2 wt% of a polymerization initiator benzyl peroxide An acrylic polymer (weight average molecular weight 700,000) was obtained by copolymerization from a toluene solution to which parts were added. The resulting acrylic polymer is subjected to an addition reaction with respect to 50 parts by weight of 2-hydroxyethyl acrylate-derived hydroxyl group methacryloyloxyethyl isocyanate (2-isocyanatoethyl methacrylate) and 100 parts by weight of the acrylic polymer. 0.03 part by weight of catalyst dibutyltin dilaurate was blended and reacted in an air atmosphere at 50 ° C. for 24 hours to produce an acrylic polymer having a methacrylate group in the side chain. 15 parts by weight of trifunctional acrylic photopolymerizable monomer (trimethylolpropane triacrylate (trade name: Aronics M320, manufactured by Toagosei Co., Ltd.)), radical light based on 100 parts by weight of the obtained acrylic polymer 1 part by weight of a polymerization initiator (trade name: Irgacure 651,2,2-dimethoxy-1,2-diphenylethane-1-one, manufactured by BASF Japan Ltd.), isocyanate compound (trade name: Coronate L, Nippon Polyurethane Industry) 1 part by weight was added to obtain a mixture.
The obtained mixture was applied to the release-treated surface of a release-treated PET film MRF38 (manufactured by Mitsubishi Resin Co., Ltd.) using a die coater so that the dry film thickness was 30 μm. Layer 1 was obtained. The peel-treated PET film MRF38 was used as a separator.

Preparation of energy ray curable pressure-sensitive adhesive layer 2 Hexafunctional acrylic photopolymerization is performed on 100 parts of a copolymer polymer composed of ethyl acrylate-2-ethylhexyl acrylate-2-hydroxyethyl acrylate (80 parts-20 parts-5 parts). 70 parts by weight of a functional monomer (dipentaerythritol hexaacrylate (trade name: A-DPH, manufactured by Shin-Nakamura Chemical Co., Ltd.)), 1 part by weight of Irgacure 651, and 0.8 part by weight of Coronate L are added to obtain a mixture. It was. The obtained mixture was applied to the release-treated surface of a release-treated PET film MRF38 (manufactured by Mitsubishi Resin Co., Ltd.) using a die coater so that the dry film thickness was 30 μm. Layer 2 was obtained.

Preparation of heat-peelable pressure-sensitive adhesive layer To 100 parts of a copolymer polymer consisting of ethyl acrylate-2-ethylhexyl acrylate-2-hydroxyethyl acrylate (80 parts-20 parts-5 parts), “Coronate L” (crosslinking agent, 1 part of Nippon Polyurethane Industry Co., Ltd. and 30 parts of 170 ° C foam expansion type thermally expandable microsphere “Matsumoto Microsphere F-100D” (thermally expandable microsphere, manufactured by Matsumoto Yushi Seiyaku Co., Ltd.) The liquid mixture was adjusted by mixing. This mixed solution was applied onto a release-treated surface of a release-treated PET film MRF38 (manufactured by Mitsubishi Resin Co., Ltd.) and dried to obtain a 50 μm heat-peelable pressure-sensitive adhesive layer.

Example 1
The energy ray curable pressure-sensitive adhesive layer 1 is bonded to the organic coating layer side of the base material 1 with the organic coating layer, and then the heat-peeling pressure-sensitive adhesive layer is bonded to the other surface of the base material to heat-release type. An adhesive sheet was prepared.
Example 2
The energy ray-curable pressure-sensitive adhesive layer 1 is bonded to the organic coating layer side of the base material 2 with the organic coating layer, and then the heat-peelable pressure-sensitive adhesive layer is bonded to the other surface of the base material to heat-release type An adhesive sheet was prepared.
Example 3
The energy ray curable pressure-sensitive adhesive layer 1 is bonded to the organic coating layer side of the base material 3 with the organic coating layer, and then the heat-peeling pressure-sensitive adhesive layer is bonded to the other surface of the base material to heat-release type. An adhesive sheet was prepared.
Example 4
The energy ray curable pressure-sensitive adhesive layer 1 is bonded to the organic coating layer side of the base material 4 with an organic coating layer, and then the heat-peeling pressure-sensitive adhesive layer is bonded to the other surface of the base material to heat-release type. An adhesive sheet was prepared.
Example 5
The energy ray curable pressure-sensitive adhesive layer 2 is bonded to the organic coating layer side of the base material 1 with an organic coating layer, and then the heat-peeling pressure-sensitive adhesive layer is bonded to the other surface of the base material to heat release type. An adhesive sheet was prepared.
Example 6
The energy ray-curable pressure-sensitive adhesive layer 2 is bonded to the organic coating layer side of the base material 2 with the organic coating layer, and then the heat-peelable pressure-sensitive adhesive layer is bonded to the other surface of the base material to heat-release type An adhesive sheet was prepared.

Comparative Example 1
The energy ray-curable pressure-sensitive adhesive layer 1 is bonded to Toray Industries, Inc. PET film, Lumirror S10 (thickness 50 μm), and then the heat-peelable pressure-sensitive adhesive layer is bonded to the other surface of the substrate, followed by heat peeling. A mold pressure-sensitive adhesive sheet was prepared.
Comparative Example 2
Toray Industries, Ltd., single-sided corona-treated, Lumirror S105 (thickness 50 μm) is bonded with the energy ray curable pressure-sensitive adhesive layer 1 and then the heat-peelable pressure-sensitive adhesive layer is bonded onto the other surface of the substrate. Thus, a heat-peelable pressure-sensitive adhesive sheet was produced.
Comparative Example 3
The energy ray-curable pressure-sensitive adhesive layer 2 is bonded to Toray Industries, Inc. PET film, Lumirror S10 (thickness 50 μm), and then the heat-peelable pressure-sensitive adhesive layer is bonded to the other surface of the substrate, followed by heat peeling. A mold pressure-sensitive adhesive sheet was prepared.
Comparative Example 4
Toray Industries, Inc., single-sided corona-treated, Lumilar S105 (thickness 50 μm) is bonded with the energy ray curable pressure-sensitive adhesive layer 2 and then the heat-peelable pressure-sensitive adhesive layer is bonded onto the other surface of the substrate. Thus, a heat-peelable pressure-sensitive adhesive sheet was produced.
Reference example 1
The energy ray curable pressure-sensitive adhesive layer 1 is bonded to the organic coating layer side of the base material 5 with the organic coating layer, and then the heat-peeling pressure-sensitive adhesive layer is bonded to the other surface of the base material to heat-release type. An adhesive sheet was prepared.
Reference example 2
The energy ray curable pressure-sensitive adhesive layer 1 is bonded to the organic coating layer side of the base material 6 with the organic coating layer, and then the heat-peeling pressure-sensitive adhesive layer is bonded to the other surface of the base material to heat-release type. An adhesive sheet was prepared.

Wafer A (thickness: 725 μm, 6 inches: support) is cut on the surface of the heat-peelable pressure-sensitive adhesive sheet of the heat-peelable pressure-sensitive adhesive sheet, and the surface of the energy ray-curable pressure-sensitive adhesive is 10 mm long and 10 μm wide, with 5 μm cuts in a grid pattern Wafer B (thickness: 725 μm, 6 inches: work piece) was bonded. Next, the back surface of the wafer B was mechanically ground to 100 μm. Then, UV irradiation of 300 mJ / cm ^{2 was} performed using a UV irradiation machine NEL UM810 (high pressure mercury lamp light source, 20 mW / cm ² ) manufactured by Nitto Seiki Co., Ltd., and the energy ray curable adhesive layer was cured. Subsequently, the wafer A was recovered by thermal expansion by raising the temperature to 170 ° C., and then the heat-peelable pressure-sensitive adhesive sheet remaining on the wafer B was peeled off with a peel at a speed of 1 m / min.

Evaluation of adhesive residue The number of adhesive residues in 100 sections in the shape of creases on the wafer surface after peeling was observed with an optical microscope.

The above Examples and Comparative Examples and the results are shown in Table 1 below.

Examples shown in Examples 1 to 6 are all examples according to the present invention in which an organic coating layer is provided. According to these examples, the number of adhesive residues (adhesive peeling) was 0 or 30 and the result was extremely excellent.
However, according to Comparative Examples 1 to 4 in which no organic coating layer was provided, a large amount of adhesive residue (glue peeling) occurred, resulting in contamination of the workpiece surface after the workpiece was peeled off.
Further, as shown in Reference Examples 1 and 2, when an organic coating layer was provided, but a copolymer having no urethane bond was used as a binder, 33 or 28 pieces of glue were peeled off. According to Reference Examples 1 and 2, it is apparent that the number of pieces peeled off is obviously smaller than that in the case where no organic coating layer is provided, and the degree of contamination on the workpiece surface is correspondingly reduced.

Claims

A heat-peelable pressure-sensitive adhesive sheet comprising a heat-peelable pressure-sensitive adhesive layer containing thermally expandable microspheres on one surface of a base material, and energy ray-curable elasticity via an organic coating layer on the other surface A heat-peelable pressure-sensitive adhesive sheet comprising a layer.
The heat-peelable pressure-sensitive adhesive sheet according to claim 1, wherein the organic coating layer is formed using polyurethane, urethane-modified vinyl acetate-vinyl chloride copolymer, polyacryl urethane, polyurethane polyester, or a precursor thereof.
The heat-peelable pressure-sensitive adhesive sheet according to claim 1 or 2, wherein the energy ray-curable elastic layer has a thickness of 3 to 300 µm.
A heat-peelable pressure-sensitive adhesive sheet comprising a heat-peelable pressure-sensitive adhesive layer containing thermally expandable microspheres on one surface of a substrate, wherein the heat-peelable pressure-sensitive adhesive layer is an energy ray-curable elastic layer or organic A heat-peelable pressure-sensitive adhesive sheet, which is provided via a coating layer and an energy ray-curable elastic layer, and has an energy ray-curable elastic layer disposed on the other surface via an organic coating layer.
The heat-peelable pressure-sensitive adhesive sheet according to claim 4, wherein the organic coating layer is formed using polyurethane, urethane-modified vinyl acetate-vinyl chloride copolymer, polyacryl urethane, polyurethane polyester, or a precursor thereof.
The heat-peelable pressure-sensitive adhesive sheet according to claim 4 or 5, wherein the energy ray-curable elastic layer has a thickness of 3 to 300 µm.
A method for processing a workpiece, wherein the workpiece is processed in a state where the workpiece is attached to the heat-peelable pressure-sensitive adhesive sheet according to any one of 1 to 6.