KR101950051B1 - Heat-releasable adhesive sheet for cutting electrical component and electrical component cutting method - Google Patents

Abstract

The energy radiation curable elastic layer and the heat peelable pressure sensitive adhesive layer prevent the convex portion due to the thermally expandable microspheres from appearing on the heat peelable pressure sensitive adhesive layer. In addition, by providing a thermally expandable microsphere over the energy ray curable elastic layer and the heat peelable pressure sensitive adhesive layer, and by thinning the heat peelable pressure sensitive adhesive layer, it is possible to prevent defective processing due to displacement of the electronic component So that it is processed with high precision. Further, the adhesion between the substrate and the energy ray-curable elastic layer is improved, thereby preventing the workpiece after peeling from being peeled off, that is, leaving the peel. A heat-peelable pressure-sensitive adhesive sheet comprising a heat-peelable pressure-sensitive adhesive layer containing heat-expandable microspheres interposed between at least one side of a substrate and an energy ray ray-curable elastic layer interposed therebetween, And a heat-peelable pressure-sensitive adhesive sheet characterized by having an organic coating layer between the layers.

Description

TECHNICAL FIELD [0001] The present invention relates to a heat-peelable pressure-sensitive adhesive sheet for cutting electronic parts and a method for cutting electronic parts,

The present invention relates to a heat peelable adhesive sheet for cutting electronic components and a method for cutting electronic components.

With the recent miniaturization of electronic parts and semiconductors, the machining accuracy of the workpiece has been required more than ever before. In the conventional processing method using a heat-peelable pressure-sensitive adhesive sheet, since the pressure-sensitive adhesive layer is smooth and thick, sufficient processing accuracy can not be obtained due to fluctuation of the pressure-sensitive adhesive due to stress at the time of processing.

On the other hand, it is effective to make the pressure-sensitive adhesive layer thin. However, when the pressure-sensitive adhesive layer is made too thin, appearance defects due to entrainment of bubbles or the like are caused by unevenness on the surface of the pressure- The pressure sensitive adhesive sheet can not be obtained, and the function as the pressure sensitive adhesive sheet for fixing can not be exhibited.

Therefore, as described in Patent Document 1, an energy ray-curable, heat-peelable pressure-sensitive adhesive sheet in which a heat-expandable pressure-sensitive adhesive layer containing heat-expandable microspheres are laminated on a substrate via an energy ray- There has been known a method of fixing a component or a semiconductor wafer and curing the energy ray curable elastic layer at the time of processing so as to reduce the fluctuation of the pressure-sensitive adhesive at the time of processing, thereby improving the processing accuracy and easily recovering the components by heat peeling after processing .

Patent Document 1: Japanese Patent Application Laid-Open No. 2002-121505

However, in the conventional energy ray-curable, heat-peelable pressure-sensitive adhesive sheet used in this method, the adhesion between the energy ray curable elastic layer and the substrate after curing is insufficient, and the energy ray curable elastic layer is partially peeled There may be a case where an adhesive is left on the adherend, and in addition, there is a case in which the section by the cutting step is not perpendicular to the surface, so that the section can not be cut accurately.

The inventors of the present invention have made intensive studies on the detachment and peeling of the conventional energy ray-curable, heat-peelable pressure-sensitive adhesive sheet. As a result, the present inventors have found that a method of increasing the chemical affinity between the pressure-sensitive adhesive layer and the substrate and a method of forming fine irregularities on the surface of the substrate, A method for increasing the thickness of the adhesive sheet, and a method for increasing the thickness of the adhesive sheet. The trial and error of the construction of the heat-peelable pressure-sensitive adhesive sheet capable of effectively suppressing the projecting breakage of this kind of pressure-sensitive adhesive sheet was repeated to complete the present invention.

That is, in the heat-peelable pressure-sensitive adhesive sheet of the present invention,

1. A heat-peelable pressure-sensitive adhesive sheet comprising, on at least one side of a substrate, a heat-peelable pressure-sensitive adhesive layer containing heat-expandable microspheres through an energy ray curable elastic layer interposed between the substrate and the energy ray- Sensitive adhesive sheet. ≪ / RTI >

2. The heat-peelable pressure-sensitive adhesive sheet according to claim 1, wherein the organic coating layer is formed from a urethane-based polymer.

3. The heat-peelable pressure-sensitive adhesive sheet according to claim 1 or 2, wherein the thickness of the heat-peelable pressure-sensitive adhesive layer is 50 占 퐉 or less.

4. The heat-peelable pressure-sensitive adhesive sheet according to any one of claims 1 to 3, wherein the energy ray-curable elastic layer has a thickness of 3 to 150 占 퐉.

5. A cutting method of an electronic part, characterized in that the electronic part is temporarily fixed by the heat-peelable pressure-sensitive adhesive sheet according to any one of claims 1 to 4, and the electronic part is cut.

According to the present invention, the unevenness caused by the thermally expandable microspheres formed on the heat-peelable pressure-sensitive adhesive layer thinner than the maximum particle diameter of the heat-expandable microspheres is absorbed and absorbed by the flexible energy ray curable elastic layer before curing A pressure sensitive adhesive sheet having an appearance and surface smoothness is produced and then the adhesive layer is cured after it is adhered to a workpiece and the energy ray curable elastic layer is cured to form a pressure sensitive adhesive sheet Can be obtained. Further, by processing the workpiece using the adhesive sheet, the small parts can be processed with high precision.

Further, according to the present invention, the pressure-sensitive adhesive can be displaced or pushed up during the pressing step and the cutting step, and chipping can be suppressed, and cutting can be performed perpendicularly to the surface of the workpiece.

Further, after the cutting, the cutting piece cut with a high degree of precision can be easily peeled and recovered. Therefore, the operability and workability in the peeling and collecting process of the cut pieces can be remarkably increased, and further, the productivity of the cut pieces such as a small or thin layer semiconductor chip or a multilayer capacitor chip can be greatly improved.

1 is a schematic view showing an example of a heat peelable pressure-sensitive adhesive sheet of the present invention.
2 is a schematic view showing another example of the heat peelable pressure-sensitive adhesive sheet of the present invention.
3 is a schematic view showing a step of processing an electronic part using the heat peelable pressure-sensitive adhesive sheet of the present invention.
[Description of Symbols]
1: substrate
2: organic coating layer
3: Energy ray curable elastic layer
3a: Cured elastic layer after energy ray irradiation
4: Heat-peelable pressure-sensitive adhesive layer
4a: Heat-peelable pressure-sensitive adhesive layer after heat treatment
5: Separator
6: Adhesive layer
7: Separator
8: adherend (group to be cut)
8a:
9: Energy line
10: Cutting line

As a result of intensive studies for solving the above problems, it is possible to improve these problems by using an adhesive sheet having an energy radiation curable elastic layer between the base material and the heat peelable pressure sensitive adhesive layer containing thermally expandable microspheres It has become.

In order to improve machining accuracy, unevenness caused by thermally expandable microspheres formed on the heat-peelable pressure-sensitive adhesive layer thinner than the maximum particle diameter of the heat-expandable microspheres is laminated and absorbed by bonding to a flexible energy ray curable elastic layer before curing The pressure-sensitive adhesive sheet having a good appearance and surface smoothness is produced, and after that, or after adhering to a work, the energy ray curable elastic layer is cured to reduce the thickness of the soft pressure sensitive adhesive layer (in this case, The present inventors have found that a small part can be processed with high precision by using a processing method of processing a work using an adhesive sheet.

Hereinafter, the structure of the heat peelable pressure-sensitive adhesive sheet of the present invention will be described with reference to Fig.

The heat-peelable sheet of the present invention is characterized in that a heat-peelable pressure-sensitive adhesive layer containing heat-expandable microspheres is formed on at least one side of a base material with an energy ray curable elastic layer interposed therebetween, And an organic coating layer is disposed on the surface of the pressure-sensitive adhesive sheet. The energy ray ray-curable elastic layer and the heat peelable pressure-sensitive adhesive layer may be formed on one side of the substrate or on both sides.

An adhesive layer may be formed on the other surface of the base material. When the electronic part is processed, the heat-peelable pressure-sensitive adhesive sheet having the heat-peelable pressure- And fixed to the stage with an adhesive layer on the other side of the substrate.

Of course, it is not always necessary to form the adhesive layer on the other side of the substrate. In this case, the heat-peelable pressure-sensitive adhesive sheet having the heat-peelable pressure-sensitive adhesive layer on which the electronic component is fixed is fixed For example, a vacuum chuck or the like.

Next, each layer constituting the heat peelable pressure-sensitive adhesive sheet of the present invention will be described.

[materials]

The base material 1 serves as a support matrix for the organic coating layer 2 and the energy ray curable elastic layer 3 and is heat resistant to such a degree that the mechanical properties are not impaired by the heat treatment of the heat peelable pressure- Is used.

As the substrate 1, for example, a plastic film or sheet such as a polyester, an olefin resin, or a polyvinyl chloride may be used, but the present invention is not limited thereto.

It is preferable that the base material 1 has a cutting property with respect to a cutting means such as a cutter used for cutting an adherend. When a base material having heat resistance and stretchability such as a flexible polyolefin film or sheet is used as the base material 1, the base material can be stretched later when the cutting edge is in the middle of the base material during the cutting step of the adherend, It is suitable for a cutting-piece collecting method which requires a gap between cutting pieces.

In addition, since the energy ray is used to cure the energy ray curable elastic layer 3, the base material 1, the organic coating layer 2 (or the heat peelable pressure sensitive adhesive layer 4 or the like) It is necessary to be made of a permeable material. The base material 1 may be a single layer or a multilayer body. It is also possible to form an energy ray curable elastic layer on the treated surface by subjecting the base material 1 to surface treatment with an appropriate releasing agent to be described later and to irradiate the obtained energy ray curable type thermally expandable pressure sensitive adhesive sheet with an energy ray, It is also possible to make the energy ray ray-curable, heat-expandable pressure-sensitive adhesive sheet itself thin by peeling the base material 1 after curing the layer.

The thickness of the substrate 1 can be appropriately selected within a range that does not impair operability and workability in each step such as bonding of an adherend, cutting of an adherend, peeling and recovery of a cut piece, Preferably about 3 to 300 mu m, and more preferably about 5 to 250 mu m.

The surface of the base material 1 is subjected to chemical or physical treatments such as surface treatments for common use such as chromic acid treatment, ozone exposure, flame exposure, high voltage exposure, and ionizing radiation treatment in order to improve the adhesion with the adjacent layer, , A coating treatment with an undercoating agent (for example, an adhesive material described later), or the like may be performed.

[Organic Coating Layer]

It is necessary that the organic coating layer 2 is adhered well to the base material 1 so that the energy radiation curable elastic layer is not subjected to implant breaking after heat peeling.

Whether or not the projectile breakage occurs can be evaluated, for example, by the method described in the following examples. Since the substrate and the heat-peelable pressure-sensitive adhesive layer are more strongly adhered to each other with the organic coating layer 2 interposed therebetween, the heat peelable pressure-sensitive adhesive sheet of the present invention is excellent in heat peeling property, , That is, does not generate a residual pool.

The organic coating layer 2 may be made of any material having such characteristics.

For example, it is possible to use various coating materials as disclosed in the literature (Plastic Hard Coat Material II, CMC Publishing, (2004)). Of these, urethane-based polymers are preferable. This is because it exhibits excellent adhesion to the substrate and also exhibits excellent anodising properties with respect to the energy ray curable elastic layer (particularly after curing). Particularly, polyacryl urethane and polyester polyurethane, and precursors thereof are more preferable. These materials are practical such as easy coating and coating of the substrate 1, and various kinds of materials can be industrially selected, and they can be obtained at low cost.

As the polyacrylic urethane and the polyester polyurethane, there can be cited (for example, Japanese Patent Application Laid-Open (Kokai) Can 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 another component, a chain extender such as polyamine and the like, an antioxidant, an oxidation stabilizer and the like may be contained.

The polyacrylic urethane and the polyester polyurethane may be those prepared by reacting the above-mentioned monomers, and those which are commercially available or used as a coating material, an ink, or a binder resin of a paint may be used (see, for example, the latest polyurethane materials and applications Technology, P190, CMC Publication (2005)). Examples of such polyurethanes include "NB300" manufactured by Dainichi Seika Kogyo Co., "Adekabon Titr (registered trademark)" manufactured by ADEKA, "Takelak (registered trademark) A / Takenate (registered trademark) A Quot; UC sealer " manufactured by DIC Graphics, and the like.

The dye may be added to such a polymer and printed on the film layer as ink. At this time, for example, a polyurethane-modified resin such as a polyurethane-vinyl acetate-vinyl chloride copolymer (NB300, manufactured by Dainichi) can be used, and the design of the pressure-sensitive adhesive sheet can be improved by such printing.

Particularly, the reason why the polyacrylic urethane and the polyester polyurethane show good adhesion to the substrate is that the isocyanate component contained as a monomer reacts with a polar functional group such as a hydroxyl group or a carboxyl group present on the substrate surface to form a strong bond .

Particularly, in order to enhance the transparency with the energy ray curable elastic layer after the energy ray curing, radical species generated in the vicinity of the urethane bond during irradiation with ultraviolet rays and radical paper generated in the energy ray curable elastic layer (Refer to: Structure and Properties of Polyurethane and High Functionality and Application Development, p191-194, Technical Information Association (1999)).

The thickness of the organic coating layer is not particularly limited, but is suitably about 0.1 to 10 mu m, preferably about 0.1 to 5 mu m, and more preferably about 0.5 to 5 mu m.

[Energy ray curable elastic layer]

The energy ray curable elastic layer 3 contains an energy ray ray-curable compound (or energy ray curable resin) for imparting energy ray curability, and when the heat releasable pressure sensitive adhesive layer 4 is pressed, the heat ray- (See the enlarged view of Fig. 1). It is preferable that the energy ray curable elastic layer 3 becomes an elastic body after irradiation with energy rays. From this viewpoint, the energy ray ray-curable elastic layer 3 can be formed by using an energy ray-curable compound (pressure-sensitive adhesive) chemically modified with an energy ray-reactive functional group or by blending an energy ray curable compound It is preferable that it is constituted by a composition.

Examples of the above-mentioned pigments include natural rubber, synthetic rubber or a rubber-based pressure-sensitive adhesive using them, silicone rubber or a pressure-sensitive adhesive, (meth) acrylic acid alkyl esters such as methyl, ethyl, propyl, , C _{1 -20} alkyl esters such as butyl ester, isobutyl ester, hexyl ester, octyl ester, 2-ethylhexyl ester, isooctyl ester, isodecyl ester and dodecyl ester] ) Acrylic acid alkyl ester (e.g., a monomer containing a carboxyl group or an acid anhydride group such as acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, and maleic anhydride; Hydroxyl group-containing monomers such as 2-hydroxyethyl (meth) acrylate; Sulfonic acid group-containing monomers such as styrenesulfonic acid; Monomers containing phosphoric acid groups such as 2-hydroxyethyl acryloyl phosphate; Amide group-containing monomers such as (meth) acrylamide; Amino group-containing monomers such as aminoethyl (meth) acrylate; Alkoxy group-containing monomers such as methoxyethyl (meth) acrylate; Imide group-containing monomers such as N-cyclohexylmaleimide; Vinyl esters such as vinyl acetate; Vinyl group-containing heterocyclic compounds such as N-vinylpyrrolidone; Styrene-based monomers such as styrene and? -Methylstyrene; Cyano group-containing monomers such as acrylonitrile; An epoxy group-containing acrylic monomer such as glycidyl (meth) acrylate; Vinyl ether-based monomers such as vinyl ethers, etc.) or an organic viscoelastic material having a suitable viscoelasticity such as a polyurethane resin, a pressure-sensitive adhesive, or an ethylene-vinyl acetate copolymer can be used. The energy ray-curable elastic layer 3 and the heat-peelable pressure-sensitive adhesive layer 4 can be adhered to each other with good adhesiveness by using the same or the same kinds of components as the pressure-sensitive adhesive constituting the heat-peelable pressure- Can be stacked. Preferable pigments include adhesive substances such as acrylic pressure-sensitive adhesives. The parent agent may be composed of one kind of component or two or more kinds of components.

Examples of the energy ray-reactive functional group used in the chemical formula include functional groups having carbon-carbon multiple bonds such as acryloyl group, methacryloyl group, vinyl group, allyl group, and acetylene group. These may be used alone or in combination of two or more. In these functional groups, carbon-carbon multiple bonds are cleaved by irradiation of energy rays to generate radicals, and these radicals become crosslinking points to form a three-dimensional mesh structure.

Among them, the (meth) acryloyl group exhibits relatively high reactivity with respect to the energy ray, and can be selected from a variety of acrylic pressure-sensitive adhesives and used in combination. From the viewpoints of reactivity and workability, the (meth) acryloyl group is preferable.

Representative examples of the chemically modified pigments chemically modified with energy ray-reactive functional groups include monomers containing a reactive functional group such as a hydroxyl group and / or a carboxyl group [e.g., (meth) acrylate 2-hydroxyethyl, (meth) (Meth) acrylic acid alkyl ester having a reactive functional group in the molecule and a group capable of reacting with the reactive functional group in the molecule (isocyanate group, epoxy group, etc.) and an energy ray-reactive functional group (acryloyl group, methacryloyl group, etc.) (E.g., (meth) acryloyloxyethylene isocyanate or the like].

The proportion 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 capable of reacting with the reactive functional group and having an energy ray-reactive functional group in the molecule is such that the amount of the reactive functional group (hydroxyl group, carboxyl group, etc.) in the reactive functional group-containing acrylic polymer , For example, 20 to 100 mol%, preferably 40 to 95 mol%. In order to accelerate the reaction involving the addition reaction of a group having a reactive group with a reactive functional group in the molecule and a reactive functional group in a reactive functional group-containing acrylic polymer with a compound having an energy ray reactive functional group, an organometallic compound such as organotin and organic zirconium Or a catalyst such as an amine compound may be added.

The energy ray curable compound 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 light and electron beam. However, the energy ray curable elastic layer It is preferable that the three-dimensional mesh formation of the mesh portion 3a is efficiently performed. The energy ray curable compounds may be used singly or in combination of two or more.

Specific examples of the energy ray-curable compound include, for example, trimethylolpropane triacrylate, tetramethylolmethane tetraacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol monohydroxypentaacrylate, Erythritol hexaacrylate, 1,4-butylene glycol diacrylate, 1,6-hexanediol diacrylate, and polyethylene glycol diacrylate.

(Meth) acrylate, urethane (meth) acrylate, epoxy (meth) acrylate having a (meth) acryloyl group at the molecular terminal, and the like may be used as the energy ray curable resin as the energy ray curable compound. Acrylate, an acryl resin (meth) acrylate, a thiol-ene addition type resin having an allyl group at the molecular end, a light ionic polymerization type resin, a neomamoyl group-containing polymer such as polyvinyl cinnamate, A photosensitive reactive group-containing polymer such as a coordinated amino novolak resin or an acrylamide type polymer, or a photosensitive reactive group-containing oligomer. Examples of the polymer which reacts with a high energy ray include epoxidized polybutadiene, unsaturated polyester, polyglycidyl methacrylate, polyacrylamide, and polyvinylsiloxane. Further, when an energy ray-curable resin is used, the above-mentioned pigments are not necessarily required.

The compounding amount of the energy ray-curable compound is, for example, about 5 to 500 parts by weight, preferably about 15 to 300 parts by weight, more preferably about 20 to 150 parts by weight based on 100 parts by weight of the mother substrate. When the elastic modulus of elasticity of the energy ray ray-curable elastic layer 3 after energy beam irradiation is in the range of 5 × 10 ^{6 to} 1 × 10 ¹⁰ Pa (frequency: 1 Hz, sample: 1.5 mm film thickness) at 20 ° C. , It is possible to achieve both good cutting workability and heat peelability. The storage elastic modulus can be adjusted by appropriately selecting the type and amount of the energy ray curable compound, the energy ray irradiation conditions, and the like.

If necessary, an energy ray polymerization accelerator may be used together with the above-mentioned energy ray polymerization initiator.

In addition to the above components, the energy ray curable elastic layer 3 is provided with an energy ray polymerization initiator for curing the energy ray curable compound, and a heat polymerization initiator, a crosslinking agent, a tackifier, a vulcanizer A suitable additive such as an antioxidant, a filler, an antioxidant, an antioxidant, and a colorant may be incorporated as needed.

As the energy ray polymerization initiator, a known or publicly known polymerization initiator may be appropriately selected depending on the kind of energy ray to be used.

When polymerization and curing are performed using ultraviolet rays as an energy ray, a photopolymerization initiator is included for curing. Examples of the photopolymerization initiator include, but are not limited to, 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 and 1-hydroxy-cyclohexyl-phenyl ketone; Substituted alpha ketols such as 2-methyl-2-hydroxypropiophenone; Aromatic sulfonyl chlorides such as 2-naphthalenesulfonyl chloride; Optically active oximes such as 1-phenyl-1,1-propanedione-2- (o-ethoxycarbonyl) oxime; Acylphosphine oxides such as 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide and bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide.

The energy ray curable elastic layer 3 is formed by applying a coating solution containing an energy ray curable resin or a parent agent, an energy ray polymerizable compound, an energy ray polymerization initiator and, if necessary, additives, , Or a method of applying the coating liquid on a suitable separator (release paper or the like) to form an energy ray curable elastic layer 3 and transferring (adhering) it onto the base material 1 .

When curing the energy ray ray-curable elastic layer, if there is a fear of occurrence of polymerization inhibition by oxygen, a peeled sheet may be placed on a mixture of the urethane polymer and the radical polymerizable monomer coated on the separator to block oxygen Alternatively, the substrate may be placed in a container filled with an inert gas to lower the oxygen concentration.

The kind of the energy ray and the type of the lamp to be used by the irradiation can be appropriately selected and a low pressure lamp such as a fluorescent chemical lamp, a black light and a sterilizing lamp, a high pressure lamp such as a metal halide lamp and a high pressure mercury lamp, Can be used. The amount of irradiation of ultraviolet rays or the like can be set arbitrarily according to the characteristics of the energy ray-curable elastic layer required.

From the viewpoints of relieving the unevenness of the heat-expandable microspheres included in the heat-peelable pressure-sensitive adhesive layer 4 and preventing vibration due to the rotating blade when the adherend is cut, the thickness of the energy ray curable elastic layer 3 is preferably 3 Preferably about 5 to 150 mu m, more preferably about 10 to 150 mu m, and even more preferably about 15 to 100 mu m.

[Heat-peelable pressure-sensitive adhesive layer]

The heat-peelable pressure-sensitive adhesive layer 4 includes a sticky material for imparting tackiness and a thermally expandable microsphere for imparting thermal expansion.

The heat-peelable pressure-sensitive adhesive layer (4) is a layer in which heat-expandable microspheres are foamed to reduce the adhesion area and facilitate peeling. The thermally expandable microspheres may be used alone or in combination of two or more. The average particle diameter of the thermally expandable microspheres is preferably about 1 to 25 mu m. More preferably 5 占 퐉 to 15 占 퐉, and particularly preferably about 10 占 퐉. The maximum particle diameter of the thermally expandable microspheres is larger than the average particle diameter.

The thermally expandable microspheres can be appropriately selected from well-known thermally expandable microspheres. As the thermally expandable microspheres, thermally expandable microspheres that are not microencapsulated can not stably exhibit good releasability. Therefore, microencapsulated thermally expandable microspheres can be suitably used.

1, it is preferable that the surface of the heat-peelable pressure-sensitive adhesive layer 4 is smooth without having irregularities reflecting the shape of the thermally expandable microspheres contained therein. Even when the thermally expandable microspheres are not contained within the thickness of the layer of the heat-peelable pressure-sensitive adhesive layer 4 due to the presence of the large thermally expandable microspheres, by embedding the convex portions of the thermally expandable microspheres in the layer of the energy ray- , The surface of the thermally expandable pressure-sensitive adhesive layer 4 is preferably smoothed.

As the sticky material, one having elasticity that allows foaming and / or swelling of the thermo-expandable microspheres upon heating and is not restrained is used. For this reason, conventionally known pressure-sensitive adhesives (pressure-sensitive adhesives) and the like can be used. As the pressure-sensitive adhesive, for example, rubber pressure-sensitive adhesives such as natural rubber and various synthetic rubbers; Silicone pressure sensitive adhesive; Acrylic pressure sensitive adhesives such as a copolymer of a (meth) acrylic acid alkyl ester and other unsaturated monomers copolymerizable with the ester (e.g., an acrylic pressure sensitive adhesive described as a base for the energy ray curable elastic layer 3), and the like . As the heat-peelable pressure-sensitive adhesive layer 4, an energy radiation curable pressure-sensitive adhesive may be used. In that case, the dynamic elastic modulus after irradiation with energy radiation, the shear storage modulus in a temperature range at which to start the heat-expandable microspheres expanded ^{1 × 10 5 ~5 × 10 7} Pa is (frequency: 1.5 mm thick film type: 1 Hz, sample) , Good peelability can be obtained.

The thermally expandable microspheres may be microspheres in which a material that easily gasifies and expands by heating, for example, isobutane, propane, pentane, or the like, is contained in a shell having elasticity. The shell is usually formed of a thermoplastic material, a heat-melting material, a material ruptured by thermal expansion, or the like. As the material forming the shell, for example, vinylidene chloride-acrylonitrile copolymer, polyvinyl alcohol, polyvinyl butyral, polymethyl methacrylate, polyacrylonitrile, polyvinylidene chloride, . The thermally expandable microspheres can be produced by a conventional method, for example, a coacervation method, an interfacial polymerization method, or the like. As the thermally expandable microspheres, commercially available products such as Matsumoto Microsphere (trade name, manufactured by Matsumoto Yushi Pharmaceutical Co., Ltd.) may be used.

The average particle diameter of the thermally expandable microspheres is generally about 1 to 80 占 퐉, preferably about 3 to 50 占 퐉, from the viewpoints of dispersibility and thin layer formability. The thermally expansible microspheres are required to have an appropriate strength that does not rupture until the volume expansion rate becomes 5 times or more, particularly 10 times or more, in order to effectively lower the adhesive force of the heat- . In the case of using thermally expandable microspheres ruptured at a low coefficient of expansion or in the case of using a thermally expanding agent that is not microcapsulated, the adhesive area between the heat-peelable pressure-sensitive adhesive layer 4 and the adherend is not sufficiently reduced, It is difficult to obtain the peelability.

The amount of the thermally expandable microspheres to be used varies depending on the type thereof, but is preferably 10 to 200 parts by weight, preferably 20 to 125 parts by weight per 100 parts by weight of the pressure-sensitive adhesive base polymer constituting the heat- to be. When the amount of the heat-releasable pressure-sensitive adhesive layer (4) is less than 10 parts by weight, deterioration of the adhesive force after heat treatment is liable to become insufficient, and when the amount exceeds 200 parts by weight, The interface breakage of the layer 4 is apt to occur.

The heat-peelable pressure-sensitive adhesive layer 4 may contain a pressure-sensitive adhesive, a heat-expandable microsphere, a crosslinking agent (e.g., A plasticizer, a pigment, a filler, an antioxidant, a surfactant, and an antistatic agent may be added to the resin composition of the present invention.

The heat-peelable pressure-sensitive adhesive layer 4 can be formed, for example, by directly applying a coating solution containing an adhesive, heat-expandable microspheres and, if necessary, additives, solvents and the like onto the energy ray curable elastic layer 3, Sensitive adhesive layer 4 is formed by applying the coating liquid onto a suitable separator 5 such as a separator (peeling paper or the like) 5, and the pressure-sensitive adhesive layer 4 is pressed and transferred onto the energy ray curable elastic layer 3 And the like), or the like.

The separator 5 is a sheet formed by forming a releasing agent layer on one side of a base film as necessary and a sheet which is peeled to protect the surface layer of the heat peelable pressure sensitive adhesive sheet of the present invention and exposed before use, And is also a sheet serving as a base when the heat-peelable pressure-sensitive adhesive layer 4 is formed.

As the base film of the separator, a known film can be used. Examples of the base film of the separator include polyether ether ketone, polyether imide, polyarylate, polyethylene naphthalate, polyethylene film, polypropylene film, polybutene film, polybutadiene film, , A polyvinyl chloride film, a vinyl chloride copolymer film, a polyethylene terephthalate film, a polybutylene terephthalate film, a polyurethane film, an ethylene-vinyl acetate copolymer film, an ionomer resin film, an ethylene- (meth) , An ethylene- (meth) acrylic acid ester copolymer film, a polystyrene film, and a polycarbonate film.

The releasable layer that can be used is selected depending on the resin of the pressure-sensitive adhesive layer by a known releasing agent such as a fluorinated silicone resin releasing agent, a fluorine resin releasing agent, a silicone resin releasing agent, a polyvinyl alcohol resin, a polypropylene resin, .

The thickness of the heat-peelable pressure-sensitive adhesive layer 4 can be suitably determined in accordance with the intended use of the pressure-sensitive adhesive sheet and the low sensitivity of the adhesive force due to heating, but it is preferable that the thickness is thin in order to improve the workability of the workpiece. Therefore, the thickness of the heat-peelable pressure-sensitive adhesive layer 4 is 50 占 퐉 or less, preferably 25 占 퐉 or less, more preferably 10 占 퐉 or less. If the thickness of the heat-peelable pressure-sensitive adhesive layer 4 is 50 占 퐉 or less, the deformation amount of the pressure-sensitive adhesive layer is reduced and the workability accuracy is improved. In addition, when the electronic component is processed, such force is applied to the heat-peelable pressure-sensitive adhesive layer 4 through the application of the pressing force or the shearing force to the electronic component. However, since the thickness of the heat- , The heat-peelable pressure-sensitive adhesive sheet of the present invention can reliably hold the electronic component against the applied force.

When the thickness of the heat-peelable pressure-sensitive adhesive layer 4 is 50 m or less, when the workpiece fixed by the heat-peelable pressure-sensitive adhesive sheet of the present invention is processed, the deformation amount of the pressure- It is possible to prevent the position and direction of the workpiece from changing even a little, and as a result, it is possible to accurately process the workpiece.

The thickness of the heat-peelable pressure-sensitive adhesive layer 4 is preferably 1 m or more, preferably 3 m or more, more preferably 5 m or more. When the thickness of the heat-peelable pressure-sensitive adhesive layer 4 is 1 占 퐉 or more, the adherend can have an adhesive force capable of sufficiently fixing the adherend. Therefore, the adherend can be processed without causing chip spreading, for example.

As the separator 5, for example, a substrate made of a plastic film or paper surface-coated with a releasing agent typified by a silicone resin, a long chain alkyl acrylate resin, a fluorine resin, or the like, or a nonpolar polymer such as polyethylene or polypropylene A substrate having low adhesiveness can be used.

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

The energy radiation curable elastic layer 3 and the heat peelable pressure sensitive adhesive layer 4 formed thereon may be formed on both sides of the substrate 1 as well as on one side. It is also possible to form the energy ray curable elastic layer 3 and the heat peelable pressure sensitive adhesive layer 4 on one side of the base material 1 in order and form a normal adhesive layer on the other side. Further, in order to prevent the fine cohesive failure at the bonding interface with the adherend due to the uneven deformation of the heat-peelable pressure-sensitive adhesive layer 4 during the heat treatment, an adhesive layer is further provided on the heat- May be formed. As the adhesive material for the adhesive layer, the adhesive described in the above-mentioned heat-peelable pressure-sensitive adhesive layer (4) can be used. The thickness of the pressure-sensitive adhesive layer is preferably 0.1 to 8 탆, particularly 1 to 5 탆, from the viewpoint of reduction or loss of adhesion to the adherend, have.

2 is a schematic sectional view showing another example of the heat peelable pressure-sensitive adhesive sheet of the present invention. In this example, an organic coating layer 2, an energy ray curable elastic layer 3, a heat peeling type pressure-sensitive adhesive layer 4 and a separator 5 are laminated in this order on one surface of a base material 1, (6) and a separator (7) are laminated on the other surface of the substrate (1). This adhesive sheet is provided with adhesive layer 6 and separator 7 on the surface opposite to the surface on which the energy ray curable elastic layer 3 of the base material 1 and the heat peelable pressure- Is formed on the surface of the adhesive sheet.

The adhesive layer (6) contains a sticky substance. The adhesive material may be the same as the adhesive material (pressure-sensitive adhesive) in the heat-peelable pressure-sensitive adhesive layer 4, and if necessary, a crosslinking agent such as an isocyanate crosslinking agent or an epoxy crosslinking agent, (For example, a rosin derivative resin, a polyterpene resin, a petroleum resin, an oil-soluble phenol resin, etc.), a plasticizer, a filler, an antioxidant and a surfactant. However, it is not preferable to use or add a substance that significantly inhibits the transmission of the energy ray for curing the energy ray curable elastic layer (3).

The thickness of the adhesive layer 6 can be suitably set within a range that does not impair the operability of the heat peelable pressure-sensitive adhesive layer 4 against the adherend, the cutting of the adherend, And is generally about 1 to 50 mu m, preferably about 3 to 30 mu m.

The adhesive layer 6 can be formed by a method similar to that of the heat-peelable pressure-sensitive adhesive layer 4. As the separator 7, the same material as the separator 5 on the heat-peelable pressure-sensitive adhesive layer 4 can be used. Such an adhesive sheet can be fixed to the pedestal surface by using the adhesive layer (6).

[Method of producing heat-peelable pressure-sensitive adhesive sheet]

The organic coating layer 2 is formed on one side or both sides of the base material 1 and the composition before curing constituting the energy ray ray-curable elastic layer 3 is applied thereon uniformly by an arbitrary means. When the energy ray-curable elastic layer 3 formed on one side of the obtained substrate contains a solvent other than the reactive solvent, such a solvent is removed by drying, and the energy ray ray-curable elastic layer 3 ) Before the curing by the energy ray. However, it may be partially cured as long as it has sufficient fluidity.

Separately, a heat-peelable pressure-sensitive adhesive layer (4) coated and dried on the prepared separator is formed. Since the surface of the heat-peelable pressure-sensitive adhesive layer 4, that is, the surface of the heat-peelable pressure-sensitive adhesive layer 4, that is, the surface other than the surface thereof, is not completely embedded in the heat-peelable pressure-sensitive adhesive layer 4, Protrudes from the surface to form a convex portion.

Next, the heat-peelable pressure-sensitive adhesive layer (4) formed on the separator was laminated on the surface of the energy ray curable elastic layer (3) before curing so that the surface on which the convex portions were formed was aligned with the surface of the base material and the separator The energy ray ray-curable elastic layer 3 and the heat-peelable pressure-sensitive adhesive layer 4 are pressed against each other to fill the convex portion in the energy ray curable elastic layer 3 which is not cured.

As a result, a sheet obtained by laminating the substrate 1, the organic coating layer 2, the uncured cured energy ray-curable elastic layer 3, the heat-peelable pressure-sensitive adhesive layer 4 and the separator in this order is obtained .

The energy ray ray-curable elastic layer 3 is irradiated with energy rays from the substrate 1 side and / or the separator side to cure the uncured energy ray ray-curable elastic layer 3, Whereby the heat-peelable pressure-sensitive adhesive sheet of the present invention can be obtained.

The method of producing the heat peelable pressure sensitive adhesive sheet is a method of forming the energy ray curable elastic layer 3 and the heat peelable pressure sensitive adhesive layer 4 on one side of the base material 1, When the curing-type elastic layer 3 and the heat-peelable pressure-sensitive adhesive layer 4 are formed, this method may be carried out one by one in turn or simultaneously on both sides of the substrate.

When the adhesive layer is formed on the other surface of the substrate 1, the adhesive layer is formed at any stage before or after the step of forming the energy ray ray-curable elastic layer 3 and the heat-peelable pressure-sensitive adhesive layer 4 It is also good.

[Method of using heat-peelable pressure-sensitive adhesive sheet]

Fig. 3 is a schematic process diagram showing an example of a method of manufacturing a cut piece using the heat peelable pressure-sensitive adhesive sheet of the present invention. More specifically, Fig. 3 is a graph showing the results of the evaluation of the adhesion of an adherend (drawn group) (Fig. 3) onto the surface of the heat-peelable pressure-sensitive adhesive layer 4 of the energy ray- 8 are cured and joined together. The energy ray curable elastic layer 3 is cured by irradiating the energy ray 9 as occasion demands. The energy ray curable elastic layer 3 is then cut into a predetermined size along the cut line 10 to form a cut piece, Sectional view showing a series of steps of expanding and foaming the thermally expandable microspheres in the heat-peelable pressure-sensitive adhesive layer 4 by heat treatment to peel and recover the cut pieces 8a. After the energy ray curable elastic layer 3 is cured by irradiation of the energy ray 9, an adherend (cut base) 8 is pressed and bonded to the surface of the heat peelable pressure sensitive adhesive layer 4, It may be cut along the line 10.

Further, the use of the heat peelable pressure-sensitive adhesive sheet of the present invention is not limited to such cutting, but is generally a processing step such as grinding and punching.

In Fig. 3, reference numeral 1 denotes a substrate, 3a denotes a cured energy ray curable elastic layer after irradiation with energy rays, and 4a denotes a heat peelable pressure sensitive adhesive layer after expanding the thermally expandable microspheres by heating again after irradiation with energy rays.

The heat-releasable pressure-sensitive adhesive layer 4 and the adherend 8 of the energy ray-curable, heat-peelable pressure-sensitive adhesive sheet can be pressed by a suitable pressing means such as a rubber roller, a laminate roll, have. In addition, depending on the type of the adhesive material, the adhesive material may be heated in a temperature range in which the thermally expandable microspheres do not expand during the compression bonding process, or water or an organic solvent may be applied to activate the adhesive material.

As the energy ray 9, visible rays, ultraviolet rays, electron rays, and the like can be used. The irradiation of the energy ray 9 can be performed by an appropriate method. However, since the thermally expandable microspheres may start to expand due to the irradiation heat of the energy ray 9, it is preferable to irradiate the heat-peelable pressure-sensitive adhesive sheet for as short a time as possible, It is preferable to maintain the temperature at which the expansion does not start.

The cutting of the adherend 8 can be performed by an ordinary cutting means such as dicing, and a cutting line 10 is formed, for example, as indicated by the cutting line 10 in Fig.

The heating conditions can be appropriately set in accordance with the surface state and heat resistance of the adherend 8 (or the cutting piece 8a), the kind of the heat-expandable microspheres, the heat resistance of the pressure-sensitive adhesive sheet, the heat capacity of the adherend Typical conditions are a temperature of 350 DEG C or less and a treatment time of 30 minutes or less, and particularly preferably a temperature of 80 to 200 DEG C and a treatment time of 1 second to 15 minutes. Examples of the heating method include a hot air heating method, a hot plate contact method, and an infrared heating method, but are not particularly limited.

When the base material 1 of the heat-peelable pressure-sensitive adhesive sheet having elasticity is used, the stretching treatment can be carried out, for example, by using an ordinary stretching means used for elongating the sheets in two dimensions.

Since the heat peelable pressure sensitive adhesive sheet of the present invention has the heat peelable pressure sensitive adhesive layer 4 containing the pressure sensitive adhesive (pressure sensitive adhesive), the adherend 8 can be firmly adhered and held, The adherend 8 is not peeled off. Since the heat-peelable pressure-sensitive adhesive layer 4 can be formed thin and the energy ray-curable elastic layer 3 is cured by irradiating the energy ray before the cutting process, the adhesive layer The chipping accompanied by the swelling of the adhesive layer or the like can be cut to a predetermined size while greatly reducing the chipping and the like as compared with the conventional heat-expandable pressure-sensitive adhesive sheet. Since the heat-peelable pressure-sensitive adhesive layer 4 contains thermally expandable microspheres and has thermal expansion properties, the heat-expandable microspheres rapidly expand or expand due to the heat treatment after the cutting step. As a result, As shown, the heat-peelable pressure-sensitive adhesive layer 4 is changed in volume to form a concave-convex three-dimensional structure on its surface, and the area of adhesion with the cut piece 8a to be cut, and thus the adhesive strength, .

In this way, the curing of the energy ray curable elastic layer 3 by the energy ray irradiation and the remarkable decrease or loss of the adhesive strength by the heat treatment result in the cutting process of the adherend 8, the peeling of the cut pieces 8a , The operability and workability in the recovery process 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 the purpose of permanently adhering an adherend, but after the adherend is adhered for a predetermined period and the adherend is achieved, Suitable for the desired application. As a concrete example of such an application, a carrier tape, a carrier or a fixing material or a fixing material, a metal plate, a metal plate, or the like, such as a carrier for a component carrier or a temporary fixing in an assembling process of various electric devices, electronic devices, A surface protection material or a masking material for the purpose of preventing contamination damage of a plastic plate or a glass plate. Particularly, it can be suitably used in a manufacturing process of a small or thin semiconductor chip, a multilayer capacitor chip, and the like in a manufacturing process of an electronic part.

Example

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

Fabrication of substrate 1 on which an organic coating layer is formed

A PET film was prepared as a substrate. Lumirra S105 (thickness: 50 占 퐉), one side of which was corona-treated, was used as the PET film. The organic coating layer was coated on the corona-treated side of the substrate with a gravure coater so that the dry film thickness was 1 to 2 占 퐉 and dried to obtain the substrate 1 having the organic coating layer formed thereon. For this organic coating layer, a pale blue printing ink NB300 (manufactured by Dainichi Pharmaceutical Co., Ltd.) was used. In addition, NB300 contained a polyurethane-based vinyl acetate-vinyl chloride copolymer as a binder resin, and a strength peak thought to be urethane by IR was confirmed.

Production of substrate 2 on which an organic coating layer is formed

A PET film was prepared as a substrate. Lumirra S105 (thickness: 50 占 퐉), one side of which was corona-treated, was used as the PET film. The organic coating layer was coated on the corona-treated side of this substrate with a gravure coater so that the dry film thickness became 1 to 2 占 퐉 and dried to obtain the substrate 2 having the organic coating layer formed thereon. In this organic coating layer, a printing ink NB300 (manufactured by Dainichi Pharmaceutical Co., Ltd.) containing no pale blue dye was used. In addition, NB300 contained a polyurethane-based vinyl acetate-vinyl chloride copolymer as a binder resin, and a strength peak thought to be urethane by IR was confirmed.

Production of substrate 3 on which an organic coating layer is formed

A PET film was prepared as a substrate. Lumirra S105 (thickness: 50 占 퐉), one side of which was corona-treated, was used as the PET film. The organic coating layer was coated on the corona-treated side of this substrate with a gravure coater so that the dry film thickness became 1 to 2 占 퐉 and dried to obtain the substrate 3 having the organic coating layer formed thereon. In this organic coating layer, 71 parts by weight of a polyurethane-based primer agent Adekabon Tyler U500 (manufactured by ADEKA) and 28 parts by weight of an ethyl acetate solution of Coronate HL (manufactured by Nippon Polyurethane Industry Co., Ltd.) were used.

Fabrication of Substrate 4 with Organic Coating Layer

As the acrylic monomer, 50.0 parts of t-butyl acrylate, 30.0 parts of acrylic acid, 20.0 parts of butyl acrylate, 1.0 part of trimethylolpropane triacrylate as a multifunctional monomer, and 1.0 part of 1- [4- (2-hydroxyethoxy ) -Phenyl] -2-hydroxy-2-methyl-1-propan-1-one (trade name: Irgacure 2959, manufactured by Ciba Specialty Chemicals Co.) as polyol and polyoxy tetramethylene , 73.4 parts of glycol (molecular weight 650, manufactured by Mitsubishi Chemical Corporation), and 0.05 part of dibutyltin dilaurate as a urethane reaction catalyst, 26.6 parts of xylylene diisocyanate was added dropwise while reacting at 65 ° C for 2 hours, To obtain a polymer-acrylic monomer mixture. The polyisocyanate component and the polyol component were used in an amount of NCO / OH (equivalent ratio) = 1.25.

The obtained urethane polymer-acrylic monomer mixture was applied on a polyethylene terephthalate film (trade name: S-10, manufactured by Doraisha) having a thickness of 38 탆 so that the thickness after curing was 3 to 4 탆. (Having a thickness of 38 占 퐉) was overlaid thereon and irradiated with ultraviolet light (illuminance of 163 mW / cm2, light quantity of 2100 mJ / cm2) using a high-pressure mercury lamp on the coated PET film surface, To obtain a polyethylene terephthalate / acrylic urethane laminated sheet.

Production of Substrate 5 Having Organic Coating Layer

A PET film was prepared as a substrate. Lumirra S105 (thickness 38 占 퐉) corona-treated on one side, manufactured by Dorey Corporation, was used as the PET film. The organic coating layer was coated on the corona-treated side of this rigid film layer with a gravure coater so that the dry film thickness became 1 to 2 占 퐉 and dried to obtain the substrate 5 having the organic coating layer formed thereon. For this organic coating layer, a blue printing ink CVL-PR (manufactured by DIC Graphics Corporation) was used. CVL-PR contains a vinyl acetate-vinyl chloride copolymer containing a hydroxyl group as a binder resin, and an IR intensity peak that can be considered as urethane was not confirmed.

Fabrication of substrate 6 on which an organic coating layer is formed

A PET film was prepared as a substrate. Lumirra S105 (thickness: 50 占 퐉), one side of which was corona-treated, was used as the PET film. The organic coating layer was coated on the corona-treated side of this substrate with a gravure coater so as to have a dry film thickness of 1 to 2 mu m and dried to obtain a substrate 6 having an organic coating layer formed thereon. An amorphous saturated copolymerized polyester resin (trade name: Vylon 200, manufactured by Toyo Boseki Co., Ltd.) was used for the organic coating layer.

Fabrication of energy ray curable pressure sensitive adhesive layer

Was copolymerized from a toluene solution to which 100 parts by weight of a 2-ethylhexyl acrylate: morpholyl acrylate: 2-hydroxyethyl acrylate = 75: 25: 20 (molar ratio) mixture was added with 0.2 part by weight of a polymerization initiator benzyl peroxide to obtain an acrylic polymer (Weight average molecular weight: 700,000). To the obtained acrylic polymer was added 50 parts by weight of methacryloyloxyethylisocyanate (2-isocyanatoethyl methacrylate) of 50 mol% of the hydroxyl group derived from 2-hydroxyethyl acrylate and 100 parts by weight of the acrylic polymer , 0.03 parts by weight of dibutyltin dilaurate as an addition reaction catalyst, and reacted at 50 占 폚 in an air atmosphere for 24 hours to prepare an acrylic polymer having a methacrylate group in its side chain. 15 parts by weight of a trifunctional acrylic photopolymerizable monomer (trimethylolpropane triacrylate (trade name: Allonix M320, manufactured by TOA Corporation)), 100 parts by weight of a radical photopolymerization initiator (Irgacure 651 , 1 part by weight of 2,2-dimethoxy-1,2-diphenylethane-1-one, manufactured by Chiba Chemical Co., Ltd.) and 1 part by weight of an isocyanate compound (trade name: Coronate L manufactured by Nippon Polyurethane Industry Co., To obtain a mixture.

The obtained mixture was applied to the exfoliated surface of the exfoliated PET film MRF38 (manufactured by Mitsubishi Polyester Co., Ltd.) using a die coater so that the dry film thickness became 30 占 퐉. Further, the peeled PET film MRF38 was used as a separator.

Production of heat-peelable pressure-sensitive adhesive layer

Ethyl acrylate-2-ethylhexyl acrylate-2-hydroxyethyl acrylate (80 parts-20 parts-5 parts) was added to 100 parts of a copolymer polymer "Coronate L" (crosslinking agent, manufactured by Nippon Polyurethane Industry Co., ) And 30 parts of heat expandable microspheres "Matsumoto Microsphere F-50D" (thermally expandable microspheres, manufactured by Matsumoto Oil Co., Ltd.) at 120 ° C were mixed to prepare a mixed solution. This mixed solution was coated on the exfoliated surface of the exfoliated PET film MRF38 (manufactured by Mitsubishi Polyester Co., Ltd.) and dried to obtain a heat peelable pressure-sensitive adhesive layer having a thickness of 10 mu m.

Example 1

The energy radiation curable pressure sensitive adhesive layer was bonded to the organic coating layer side of the substrate 1 having the organic coating layer formed thereon, and then the heat releasable pressure sensitive adhesive layer was bonded to produce a heat peelable pressure sensitive adhesive sheet.

Example 2

The energy radiation curable pressure sensitive adhesive layer was bonded to the organic coating layer side of the substrate 2 having the organic coating layer formed thereon, and then the heat releasable pressure sensitive adhesive layer was bonded thereto to produce a heat peelable pressure sensitive adhesive sheet.

Example 3

The energy radiation curable pressure sensitive adhesive layer was bonded to the organic coating layer side of the substrate 3 having the organic coating layer formed thereon, and then the heat releasable pressure sensitive adhesive layer was bonded thereto to prepare a heat peelable pressure sensitive adhesive sheet.

Example 4

The above-described energy ray-curable pressure-sensitive adhesive layer was bonded to the organic coating layer side of the substrate 4 having the organic coating layer formed thereon, and then the heat-peelable pressure-sensitive adhesive layer was bonded thereon to prepare a heat peelable pressure-sensitive adhesive sheet.

Comparative Example 1

A heat-peelable pressure-sensitive adhesive sheet was prepared by bonding the above-described energy ray-curable pressure-sensitive adhesive layer to a PET film manufactured by Toray Industries, Inc., Lumirra S10 (thickness: 50 탆) and then bonding the heat-peelable pressure-sensitive adhesive layer.

Comparative Example 2

A heat-peelable pressure-sensitive adhesive sheet was produced by bonding the above-described energy ray-curable pressure-sensitive adhesive layer to a Lamora S105 (thickness: 50 占 퐉) corona-treated on one side and then bonding the heat-peelable pressure-sensitive adhesive layer.

Reference Example 1

The energy radiation curable pressure sensitive adhesive layer was bonded to the organic coating layer side of the substrate 5 having the organic coating layer formed thereon, and then the heat releasable pressure sensitive adhesive layer was bonded thereto to produce a heat peelable pressure sensitive adhesive sheet.

Reference Example 2

The energy radiation curable pressure sensitive adhesive layer was bonded to the organic coating layer side of the substrate 6 having the organic coating layer formed thereon, and then the heat releasable pressure sensitive adhesive layer was bonded thereto to produce a heat peelable pressure sensitive adhesive sheet.

Energy ray irradiation

The heat-peelable pressure-sensitive adhesive sheet thus obtained was irradiated with ultraviolet rays at 300 mJ / cm 2 using a UV irradiator NEL UM810 (high-pressure mercury lamp light source, 20 mW / cm 2) manufactured by Nitto Kasei Corporation to cure the energy radiation curable elastic layer.

A pre-fired ceramic sheet having a size of 120 mm x 100 mm x 0.5 mm thick was adhered to the pressure-sensitive adhesive side of the heat peelable pressure-sensitive adhesive sheet, and full cut was performed with a chip of 0.4 mm x 0.2 mm. Thereafter, heat treatment was performed on a hot plate at 120 DEG C for 3 minutes, cooled, and then vibrated in reverse to recover chips.

Evaluation of heat peelability

When the chip was recovered by inversely vibrating after the heat treatment, the number of chips not peeled out of 100 chips was counted.

Evaluation of full peeling property

The ceramic sheet was cut to a full cut, and the pressure-sensitive adhesive surface of the heat-peelable pressure-sensitive adhesive sheet subjected to the heat treatment was observed using an optical microscope, and the number of peelings in 100 chips was counted. The degree of this peeling also indicates the degree to which the surface of the chip is left untreated.

Cutting precision

In order to obtain the cutting accuracy, the following method was employed.

The cross section of the chip after cutting was observed with an optical microscope, and the angle of the cross section with respect to the surface of the ceramic sheet was obtained. The closer this is to 90 °, the better the cutting accuracy.

Each of the above-mentioned Examples and Comparative Examples and the results thereof are shown in Table 1 below.

When the ceramic sheets were fully cut using the heat-peelable pressure-sensitive adhesive sheets of Examples 1 to 6, there was no chips that were not peeled off at the time of recovering the obtained chips, so that the heat peelability was good.

In addition, the adhesive surface of the heat-peelable pressure-sensitive adhesive sheet after full-cutting had no peeling off.

According to these results, according to the present invention, the adhesive can be prevented from being displaced or pushed up and chipping can be suppressed during the cutting process, and after cutting, the cut pieces can be easily peeled and recovered with high precision . At this time, it is possible to remarkably increase the operability and workability in the peeling and collecting process of the cut pieces, and furthermore, to improve the productivity of the cut pieces such as semiconductor chips and multilayer capacitor chips with high precision, .

On the other hand, in the case of using the heat-peelable pressure-sensitive adhesive sheets of Comparative Examples 1 and 2 in which the organic coating layer was not formed, both the heat peelability and the peeling off were poor. According to Comparative Example 3, However, since the cutting precision is low, the workability at the time of full cutting of the fixed ceramic sheet is deteriorated.

The heat-peelable pressure-sensitive adhesive sheets of Reference Examples 1 and 2 are examples in which a layer made of a material other than the urethane-based polymer is used as the organic coating layer, but the heat peelability and the peeling off are all poor as in Comparative Examples 1 and 2.

In addition, according to Reference Example 3, the heat peelability is good, the peeling is not complete, and the cutting accuracy is good. However, since the thickness of the heat-peelable pressure-sensitive adhesive layer is as thin as 0.8 m, the adhesiveness for holding the adherend is insufficient, A new problem arises that the body is peeled off.

According to the results of these Examples, Comparative Examples and Reference Examples, it can be seen that the heat-peelable pressure-sensitive adhesive sheet of the present invention exhibits a remarkable effect as compared with the case where an organic coating layer composed of a urethane-based polymer is employed.

Claims (7)

A heat-peelable pressure-sensitive adhesive sheet comprising a heat-peelable pressure-sensitive adhesive layer containing heat-expandable microspheres through an energy ray-curable elastic layer on at least one side of a substrate, wherein a urethane polymer is provided between the substrate and the energy ray- Wherein the organic coating layer is provided on the surface of the pressure-sensitive adhesive sheet. The heat-peelable pressure-sensitive adhesive sheet according to claim 1, wherein the urethane-based polymer is at least one selected from polyacryl urethane and polyester polyurethane. The heat-peelable pressure-sensitive adhesive sheet according to claim 1, wherein the thickness of the heat-peelable pressure-sensitive adhesive layer is 50 占 퐉 or less. The heat-peelable pressure-sensitive adhesive sheet according to claim 2, wherein the thickness of the heat-peelable pressure-sensitive adhesive layer is 50 占 퐉 or less. The heat peelable pressure-sensitive adhesive sheet according to any one of claims 1 to 4, wherein the thickness of the energy radiation curable elastic layer is 3 to 150 占 퐉. The heat peelable pressure-sensitive adhesive sheet according to any one of claims 1 to 4, wherein the thickness of the organic coating layer is 0.1 to 10 占 퐉. A method of cutting an electronic part, characterized in that the electronic part is temporarily fixed by the heat-peelable pressure-sensitive adhesive sheet according to any one of claims 1 to 4, and the electronic part is cut.

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