JP2009035609A - Method for processing adherend using thermally releasable pressure-sensitive adhesive sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for processing an adherend by which, in a method for processing a body to be processed after fixing the body to be processed with a pressure-sensitive adhesive sheet, even when the body to be processed has an uneven surface, the adherend is firmly fixed, accurate processing can be performed, and after the processing, the body to be processed can easily be released from the pressure-sensitive adhesive sheet and recovered. <P>SOLUTION: The method for processing an adherend using a thermally releasable pressure-sensitive adhesive sheet obtained by providing a thermally expandable pressure-sensitive adhesive layer containing thermally expandable microspheres on at least one side of a substrate, is characterized in that the relationship between the maximum height Rt of a cross section of a surface of the thermally expandable pressure-sensitive adhesive layer and the maximum height Rt' of a cross section of a surface of the adherend satisfy Rt'≥Rt, and Rt is within the range of 0.5-12 μm. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for processing an adherend using a heat-peelable pressure-sensitive adhesive sheet that has excellent adhesion to an adherend and can be easily peeled off from the adherend by heat treatment at any time.

As a pressure-sensitive adhesive sheet for processing a semiconductor substrate used in a semiconductor substrate dicing process, etc., the adhesive is polymerized and cured by ultraviolet rays and / or radiation when it is picked up after being attached to a semiconductor substrate, thereby reducing the adhesive force. A technique using an adhesive sheet is known (see Patent Document 1). On the other hand, as a pressure-sensitive adhesive sheet for semiconductor substrate processing, a technology that uses a heat-peelable pressure-sensitive adhesive sheet in which the pressure-sensitive adhesive layer is composed of a heat-expandable pressure-sensitive adhesive layer containing heat-expandable microspheres and peels off by removing the adhesive force by heating. Has also been considered. Such a heat-peelable pressure-sensitive adhesive sheet is superior to a curable pressure-sensitive adhesive sheet in that it does not require irradiation equipment such as ultraviolet rays when used, and suppresses peeling resistance, but contains heat-expandable microspheres. As a result, the adhesive layer was hard and the followability to the adherend was poor.
In recent years, there are increasing numbers of semiconductor substrates having a rough surface of about 0.4 to 15 μm on the sealing resin surface on which the pressure-sensitive adhesive sheet is attached, and those having a mark printed with a depth of 25 to 40 μm by laser irradiation. Yes. When dicing a semiconductor substrate having unevenness on such a surface, the conventional heat-peelable pressure-sensitive adhesive sheet does not have sufficient followability to the unevenness, so that sufficient adhesive force cannot be obtained. There has been a problem that chips are peeled off and the yield is lowered, and a chip that has been blown hits a cutting blade and breaks the blade.

JP-A-6-49420

It is an object of the present invention to fix an adherend firmly and accurately in a method for processing a workpiece by fixing the workpiece with an adhesive sheet even when the surface of the workpiece has irregularities. It is an object of the present invention to provide a method for processing an adherend that can be easily processed and can be easily peeled off and collected from the pressure-sensitive adhesive sheet after completion of the processing.
Another object of the present invention is to manufacture a semiconductor chip by processing a semiconductor substrate having a large uneven surface, such as a semiconductor substrate having a sealing resin surface, without causing a problem such as chip skipping. It is to provide a semiconductor chip manufacturing method that can be performed.

  As a result of intensive studies to solve the above problems, the present inventors have focused on the relationship between the maximum cross-sectional height of the adhesive surface of the pressure-sensitive adhesive sheet that fixes the workpiece and the maximum cross-sectional height of the adherend surface of the workpiece. As a result, it was found that a workpiece having an uneven surface can be stably and reliably fixed, and the present invention has been completed.

  That is, the present invention relates to an adherend processing method for processing an adherend using a heat-peelable pressure-sensitive adhesive sheet in which a heat-expandable pressure-sensitive adhesive layer containing heat-expandable microspheres is provided on at least one surface of a substrate. The relationship between the maximum cross-sectional height Rt of the thermally expandable adhesive layer and the maximum cross-sectional height Rt ′ of the adherend surface satisfies Rt ′ ≧ Rt, and Rt is in the range of 0.5 to 12 μm. A method for processing an adherend is provided.

  As the heat-peelable pressure-sensitive adhesive sheet, a heat-peelable pressure-sensitive adhesive sheet having a rubber-like organic elastic layer between the substrate and the thermally expandable pressure-sensitive adhesive layer can be suitably used. It is desirable to be configured.

  The present invention also provides a method of manufacturing a semiconductor chip by processing a semiconductor substrate using a heat-peelable pressure-sensitive adhesive sheet provided with a heat-expandable pressure-sensitive adhesive layer containing heat-expandable microspheres on at least one surface of a substrate. The relationship between the maximum cross-sectional height Rt of the thermally expandable pressure-sensitive adhesive layer surface and the maximum cross-sectional height Rt ″ of the semiconductor substrate surface satisfies Rt ″ ≧ Rt, and Rt is in the range of 0.5 to 12 μm. A method for manufacturing a semiconductor chip is provided.

According to the present invention, it is possible to firmly fix the adherend (workpiece) having irregularities (rough surface) on the surface, which has been difficult to reliably fix depending on the conventional adhesive sheets, Deviation and peeling of the adherend (workpiece) during the machining operation are suppressed, and high-precision machining can be performed. In addition, after the processing step is completed, the fixing by the heat-peelable adhesive sheet can be easily released by heating, so that the quality of the adherend (workpiece) decreases due to the stress at the time of peeling, or the adherend due to adhesive residue ( Contamination of the workpiece is greatly suppressed.
In particular, when a dicing process is performed in which an electronic component assembly such as a semiconductor substrate having a sealing resin is fixed by the processing method of the present invention and singulated into a specified size, there is a problem such as chip skipping during dicing. Can be remarkably suppressed, and a decrease in yield can be suppressed.

[Heat peelable adhesive sheet]
A heat-peelable pressure-sensitive adhesive sheet that can be used in an adherend processing method and a semiconductor chip manufacturing method of the present invention will be described with reference to the drawings. FIG. 1 and FIG. 2 are schematic cross-sectional views each showing an example of a heat-peelable pressure-sensitive adhesive sheet used for fixing the adherend by the method for processing an adherend of the present invention. 1 and 2, reference numeral 1 denotes a base material, 3 denotes a thermally expandable adhesive layer having a fine uneven surface, 4 denotes a separator, and 2 in FIG. 1 denotes a rubbery organic elastic layer. FIG. 1 is a heat-peelable pressure-sensitive adhesive sheet having a rubbery organic elastic layer 2 between a substrate 1 and a heat-expandable pressure-sensitive adhesive layer 3, and FIG. It is a sheet. Any form of the pressure-sensitive adhesive sheet can be suitably used in the present invention, but a pressure-sensitive adhesive sheet having the rubber-like organic elastic layer 2 shown in FIG. 1 can be more suitably used.

(Base material)
In the heat-peelable pressure-sensitive adhesive sheet of the present invention, the base material 1 is a support base of the pressure-sensitive adhesive sheet, and generally a plastic film or sheet is used. For example, paper, cloth, nonwoven fabric, metal foil or plastics thereof An appropriate thin leaf body such as a laminate or a laminate of plastics can be used, and is not particularly limited. Although the thickness of a base material is not restrict | limited in particular, For example, it can select from the range of 5-250 micrometers.

(Thermal expansion adhesive layer)
The heat-expandable pressure-sensitive adhesive layer 3 can be formed of a heat-expandable pressure-sensitive adhesive in which heat-expandable microspheres are blended in a pressure-sensitive adhesive, and has minute irregularities on the surface (adhesive surface). As the pressure-sensitive adhesive, a known appropriate pressure-sensitive adhesive can be used, and is not particularly limited. However, a rubber-based material or a resin that allows expansion and / or expansion of the heat-expandable microsphere during heating and does not restrain it. A base pressure sensitive adhesive is preferably used.

  Such pressure-sensitive adhesives include natural rubber, various synthetic rubbers, polymers such as acrylics, vinyl alkyl ethers, silicones, polyesters, polyamides, urethanes, and styrene / diene block copolymers. And a pressure sensitive adhesive. Further, those obtained by blending these polymers with a heat-melting resin having a melting point of about 200 ° C. or less to improve the creep characteristics can be used as the base polymer.

  Among these, an acrylic copolymer can be particularly preferably used. As the main monomer component of the acrylic copolymer, it is preferable to use a (meth) acrylic acid alkyl ester having an alkyl group having 20 or less carbon atoms. Examples of the alkyl group having 20 or less carbon atoms include methyl group, ethyl group, propyl group, butyl group, amyl group, hexyl group, heptyl group, 2-ethylhexyl group, isooctyl group, isodecyl group, dodecyl group, lauryl group, Examples include tridecyl group, pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group, nonadecyl group, and eicosyl group. One or more (meth) acrylic acid alkyl esters can be selected and used as the main monomer component. These (meth) acrylic acid alkyl esters are usually contained in an amount of 50% by weight or more in the base polymer of the pressure-sensitive adhesive.

  In addition to the above (meth) acrylic acid alkyl ester, the acrylic copolymer may contain an appropriate copolymerizable monomer for the purpose of modifying cohesive force, heat resistance and the like, if necessary. Examples of the copolymerizable monomer include carboxyl group-containing monomers such as acrylic acid, methacrylic acid, carboxyethyl acrylate, carboxypentyl acrylate, itaconic acid, maleic acid, fumaric acid, and crotonic acid; maleic anhydride, itaconic anhydride, and the like. Acid anhydrides: hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, hydroxyhexyl (meth) acrylate, hydroxyoctyl (meth) acrylate, (meth) acrylic acid Hydroxyl group-containing monomers such as hydroxydecyl, hydroxylauryl (meth) acrylate, (4-hydroxymethylcyclohexyl) methyl (meth) acrylate; styrene sulfonic acid, allyl sulfonic acid, 2- (meth) acrylic Sulfonic acid group-containing monomers such as amido-2-methylpropanesulfonic acid, (meth) acrylamidepropanesulfonic acid, sulfopropyl (meth) acrylate, (meth) acryloyloxynaphthalenesulfonic acid; (meth) acrylamide and N, N-dimethyl (N-substituted) amide monomers such as (meth) acrylamide, N-butyl (meth) acrylamide, N-methylol (meth) acrylamide, N-methylolpropane (meth) acrylamide; aminoethyl (meth) acrylate, (meta ) (Meth) acrylic acid alkylamino monomers such as aminoethyl acrylate, N, N-dimethylaminoethyl (meth) acrylate, t-butylaminoethyl (meth) acrylate; methoxyethyl (meth) acrylate, ( (Meth) acrylic acid (Meth) acrylic acid alkoxyalkyl monomers such as toxiethyl; maleimide monomers such as N-cyclohexylmaleimide, N-isopropylmaleimide, N-laurylmaleimide, N-phenylmaleimide; N-methylitaconimide, N-ethylitaconimide, Itaconimide monomers such as N-butylitaconimide, N-octylitaconimide, N-2-ethylhexylitaconimide, N-cyclohexylitaconimide, N-laurylitaconimide; N- (meth) acryloyloxymethylene succinimide, N- ( Succinimide monomers such as (meth) acryloyl-6-oxyhexamethylene succinimide and N- (meth) acryloyl-8-oxyoctamethylene succinimide; vinyl acetate, pro Vinyl pionate, N-vinyl pyrrolidone, methyl vinyl pyrrolidone, vinyl pyridine, vinyl piperidone, vinyl pyrimidine, vinyl piperazine, vinyl pyrazine, vinyl pyrrole, vinyl imidazole, vinyl oxazole, vinyl morpholine, N-vinyl carboxylic acid amides, styrene, α -Vinyl monomers such as methylstyrene and N-vinylcaprolactam; Cyanoacrylate monomers such as acrylonitrile and methacrylonitrile; Epoxy group-containing acrylic monomers such as glycidyl (meth) acrylate; Polyethylene glycol (meth) acrylate and (Metal ) Glycols such as polypropylene glycol acrylate, methoxyethylene glycol (meth) acrylate, methoxypolypropylene glycol (meth) acrylate Acrylic ester monomers; (meth) acrylic acid tetrahydrofurfuryl, fluorine (meth) acrylate, silicone (meth) acrylate, 2-methoxyethyl acrylate and other acrylic ester monomers; hexanediol di (meth) acrylate, (poly) ethylene Glycol di (meth) acrylate, (poly) propylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, pentaerythritol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) Polyfunctional monomers such as acrylate, dipentaerythritol hexa (meth) acrylate, epoxy acrylate, polyester acrylate, urethane acrylate; For example, lens, butadiene, isobutylene, and vinyl ether. These copolymerizable monomers can be used alone or in combination of two or more.

  By subjecting the above-described monomer to polymerization, a base polymer constituting the heat-expandable pressure-sensitive adhesive layer 3 can be produced. The polymerization method is not particularly limited, and can be appropriately selected from commonly used polymerization methods such as a solution polymerization method, a bulk polymerization method, and an emulsion polymerization method by adding a polymerization initiator.

  Various additives may be added to the pressure-sensitive adhesive constituting the heat-expandable pressure-sensitive adhesive layer 3 as necessary. Examples of such additives include known or commonly used tackifying resins (for example, rosin resins, terpene resins, petroleum resins, coumarone-indene resins, styrene resins, etc.), and crosslinking agents (for example, epoxy-based crosslinking). Agents, isocyanate-based crosslinking agents, polyfunctional acrylate-based crosslinking agents, etc.), fillers, colorants (such as pigments and dyes), antioxidants, ultraviolet absorbers, and surfactants. The amount of these additives used may be a normal amount applied to the pressure-sensitive adhesive.

  Examples of the heat-expandable microspheres include thermal expansion in which an appropriate material that is easily gasified and exhibits expandability, such as isobutane, propane, or pentane, is encapsulated in a shell-forming material by a coacervation method or an interfacial polymerization method. Sex microspheres can be used. As the shell-forming substance, a substance exhibiting heat melting property or a substance that breaks down by thermal expansion can be used, for example, vinylidene chloride / acrylonitrile copolymer, polyvinyl alcohol, polyvinyl butyral, polymethyl methacrylate, polyacrylonitrile, polyvinylidene chloride. And polysulfone. The thermally expandable microspheres should have a volume expansion ratio of, for example, 5 times or more, preferably 7 times or more, and particularly preferably 10 times or more in order to express good heat peelability.

  The blending amount of the heat-expandable microspheres can be appropriately selected according to the degree of expansion (foaming) of the heat-peelable pressure-sensitive adhesive layer 3 and the degree of decrease of the adhesive force, and is not particularly limited. For example, it can be selected from the range of 1 to 150 parts by weight, preferably 25 to 100 parts by weight with respect to 100 parts by weight of the base polymer constituting the thermally expandable pressure-sensitive adhesive layer 3.

  The thickness of the heat-expandable pressure-sensitive adhesive layer 3 can be selected from the range of, for example, 5 to 50 μm, preferably 15 to 35 μm. If the heat-expandable pressure-sensitive adhesive layer 3 is too thin, the contact area with the adherend becomes too small due to the unevenness of the heat-expandable microspheres, and the adhesion to the adherend before heat treatment may be reduced. If the heat-expandable pressure-sensitive adhesive layer 3 is too thick, the heat-expandable pressure-sensitive adhesive layer 3 is likely to be deformed, so that it may be difficult to process with high accuracy, such as causing a shift when the adherend is processed. Further, there may be cases where good heat peelability cannot be obtained, for example, cohesive failure occurs during expansion by heat treatment and adhesive residue is generated on the adherend.

  The unevenness of the surface (adhesive surface) of the thermally expandable pressure-sensitive adhesive layer 3 may be such that the shape of each of the uneven portions may be the same shape or may be partially the same shape. Different shapes may be used. In addition, when the shapes of the uneven portions are partially the same or different from each other (that is, when they are not all the same shape), the shapes of the uneven portions may be regularly different shapes. It may have irregularly different shapes. Moreover, as a form in which each uneven part is arranged, a form arranged in a regular positional relationship (or at intervals) may be used, or a form arranged in an irregular positional relationship (or at intervals) It may be. Therefore, the concavo-convex portions have a form in which the concavo-convex portions having the same, regular or irregularly different shapes are arranged in a regular or irregular positional relationship (or at intervals). Also good. The uneven portion of the thermally expandable pressure-sensitive adhesive layer 3 is preferably an uneven portion having a form in which the uneven portions having irregularly different shapes are arranged in an irregular positional relationship.

  The maximum cross-sectional height Rt of the concavo-convex portion on the surface of the heat-expandable pressure-sensitive adhesive layer 3 can be selected from the range of 0.5 to 12 μm, preferably 1 to 12 μm, particularly preferably 3 to 8 μm. When the maximum cross-sectional height is larger than 12 μm, the maximum cross-sectional height Rt ′ of the adherend surface is often exceeded, and the adhesion force to the adherend having a rough surface becomes insufficient. Not suitable for use in body processing methods. When the maximum cross-sectional height of the pressure-sensitive adhesive layer surface exceeds 12 μm, sufficient adhesive force is often not obtained even on a smooth adherend surface. In addition, when the maximum cross-sectional height Rt is smaller than 0.5 μm, the followability to the rough surface becomes insufficient, and sufficient adhesive force necessary for processing the adherend cannot be expressed, and the adherend is accurate. Processing may not be possible.

  The surface roughness (average roughness) Ra of the surface of the heat-expandable pressure-sensitive adhesive layer 3 is not particularly limited, but can be selected from a range of 0.5 to 5 μm, preferably 1 to 3 μm, for example.

  The maximum cross-sectional height Rt and the surface roughness Ra can be measured using, for example, a contact type surface roughness measuring device “P-11” manufactured by TENCOR.

  The uneven portion on the surface of the heat-expandable pressure-sensitive adhesive layer 3 can be formed using a known or conventional uneven portion forming method. For example, prepare a coating solution in which an adhesive, thermally expandable microspheres and other components as necessary are dissolved and dispersed in an appropriate solvent, and apply the coating solution on a substrate to form an adhesive layer. After the formation, a method of bonding a separator having unevenness, or a method of applying the coating liquid on the unevenness separator to form the thermally expandable pressure-sensitive adhesive layer 3, and then on the substrate 1 or the rubbery organic elastic layer 2 The method of transferring to is mentioned. In addition, the separator which has an uneven | corrugated | grooved part can be manufactured by well-known appropriate methods, such as the method of processing a separator surface by a sandblast system etc., and the method of thermocompression-bonding the roller to which the uneven | corrugated process was given to a separator.

(Rubber organic elastic layer)
The rubbery organic elastic layer 2 is a layer provided between the base material 1 and the heat-expandable pressure-sensitive adhesive layer 3 as necessary, and when the pressure-sensitive adhesive sheet is bonded to the adherend, the surface thereof is the adherend. The surface direction of the pressure-sensitive adhesive sheet when the heat-expandable pressure-sensitive adhesive layer is foamed and / or expanded by heating the heat-expandable pressure-sensitive adhesive layer in order to peel off the adherend from the pressure-sensitive adhesive sheet. Those that serve to promote the formation of an undele structure due to the three-dimensional structural change of the thermally expandable layer by reducing the restraint of foaming and / or expansion in the interior.

  The rubbery organic elastic layer 2 can be formed of natural rubber or synthetic rubber of 50 or less, preferably 40 or less, based on ASTM D-2240 D-type Sure D-type hardness, or a synthetic resin having rubber elasticity. .

  Examples of the synthetic rubber or synthetic resin include nitrile, diene, and acrylic synthetic rubbers, thermoplastic elastomers such as polyolefins and polyesters, ethylene-vinyl acetate copolymers, polyurethanes, polybutadienes, and soft polys. Examples thereof include synthetic resins having rubber elasticity such as vinyl chloride. In addition, even if it is essentially a hard polymer such as polyvinyl chloride, a polymer having rubber elasticity in combination with a compounding agent such as a plasticizer or a softener may be used.

  In the present invention, the rubbery organic elastic layer 2 is preferably formed of an adhesive substance. As the adhesive substance constituting the rubbery organic elastic layer 2, the same material as the pressure-sensitive adhesive constituting the above-described thermally expandable adhesive layer 3 can be used. As a material constituting the rubbery organic elastic layer 2, an acrylic pressure-sensitive adhesive mainly composed of an acrylic polymer can be used particularly preferably.

  The thickness of the rubbery organic elastic layer 2 is not particularly limited, and can be selected, for example, from a range of about 1 to 200 μm, preferably about 5 to 50 μm.

(separator)
The separator 4 is a surface provided to protect the adhesive surface of the heat-expandable pressure-sensitive adhesive layer 3, but is often used for the purpose of providing an uneven portion on the surface of the heat-expandable pressure-sensitive adhesive layer 3 as described above. . As the separator 4, any suitable thin leaf can be used, and is not particularly limited. For example, polyolefin resins such as polyethylene and polypropylene can be used.

[Processing method of adherend]
In the method for processing an adherend according to the present invention, a heat-peelable pressure-sensitive adhesive sheet having a maximum cross-sectional height Rt on the surface of the above-described thermally expandable pressure-sensitive adhesive layer 3 within a range of 0.5 to 12 μm is used. The workpiece is fixed, and various processing is performed on the adherend. The adherend (workpiece) that can be processed by the method of the present invention includes the maximum cross-sectional height R ′ of the adherend surface and the maximum cross-sectional height of the surface of the thermally expandable adhesive layer 3. There is no particular limitation as long as the relationship with Rt satisfies Rt ′ ≧ Rt. Further, it is preferable that Rt ′: Rt satisfies 1: 0.2 to 1: 0.9. For example, a semiconductor substrate such as a silicon wafer, a substrate made of ceramic, a resin, etc., an electronic component assembly in which a circuit pattern is formed on these substrates, and such an electronic component assembly is sealed with a sealing resin such as an epoxy resin. Examples include adherends having a rough surface such as a sealed sealing resin package. Examples of the processing performed on the adherend include printing, marking, laminating press, cutting, grinding, and cleaning. According to the method for processing an adherend of the present invention, the surface of the heat-peelable pressure-sensitive adhesive layer 3 of the heat-peelable pressure-sensitive adhesive sheet follows the rough surface of the adherend well and exhibits sufficient adhesive force. Therefore, processing can be performed with high accuracy without causing deviation or peeling during the processing step.

  After completion of the processing step, the heat-peelable pressure-sensitive adhesive sheet can be easily peeled off from the adherend by heat treatment. The conditions of the heat treatment are determined by conditions such as the surface condition of the adherend and the reduction of the adhesion area due to the type of thermally expandable microspheres, the heat resistance of the substrate and adherend, the heating method, etc. These conditions are 100 to 250 ° C., 1 to 90 seconds (hot plate or the like) or 5 to 15 minutes (hot air dryer or the like).

  In the method for processing an adherend according to the present invention, an electronic component assembly such as a semiconductor substrate is used as the adherend (workpiece), and the electronic component assembly (semiconductor substrate or the like) is diced to a specified size. It can be separated and an electronic component such as a semiconductor chip can be manufactured. The relationship between the maximum cross-sectional height Rt ″ of the surface of the semiconductor substrate as the adherend (workpiece) and the maximum cross-sectional height Rt of the surface of the heat-expandable pressure-sensitive adhesive sheet 3 satisfies Rt ″ ≧ Rt. In addition, when the maximum cross-sectional height Rt of the surface of the thermally expandable adhesive layer 3 is in the range of 0.5 to 12 μm, the adherend is firmly fixed at the time of dicing, and problems such as displacement and chip jumping are caused. High-precision cutting can be efficiently performed without occurrence, and after the dicing is completed, the obtained electronic component can be easily peeled off from the adhesive sheet by heating. When the semiconductor substrate has a sealing resin, the sealing resin surface is usually the adherent surface when fixing with the heat-peelable pressure-sensitive adhesive sheet. In this case, the maximum cross-sectional height of the sealing resin surface is It is necessary that the height is equal to or greater than the maximum cross-sectional height of the surface of the heat-expandable pressure-sensitive adhesive layer 3.

  EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

(Production Example 1)
Acrylic copolymer (pressure-sensitive adhesive) comprising 2-ethylhexyl acrylate (30 parts by weight), ethyl acrylate (70 parts by weight), methyl methacrylate (5 parts by weight) and isocyanate-based crosslinking agent (1 part by weight) ) Was dissolved in toluene. The solution was applied onto a polyester film having a thickness of 100 μm so that the thickness after drying was 30 μm to obtain a rubbery organic elastic layer.
Acrylic copolymer (pressure-sensitive adhesive) comprising 2-ethylhexyl acrylate (30 parts by weight), ethyl acrylate (70 parts by weight), methyl methacrylate (5 parts by weight) and an isocyanate-based crosslinking agent (2 parts by weight) ) 100 parts by weight and 30 parts by weight of thermally expandable microspheres (Matsumoto Yushi Seiyaku: trade name “Matsumoto Microsphere F-30D”) having an average particle diameter of 13.5 μm are uniformly mixed and dissolved in toluene. The surface of the separator was provided with irregularities having a maximum cross-sectional height of 4.8 μm by a sandblasting method, and the coating liquid was applied to the irregular surface of the separator so that the thickness after drying was 30 μm. A heat-expandable adhesive layer was obtained.
The rubber-like organic elastic layer and the heat-expandable pressure-sensitive adhesive layer were bonded together to obtain a heat-peelable pressure-sensitive adhesive sheet A comprising a base material, a rubber-like organic elastic layer, a heat-expandable pressure-sensitive adhesive layer, and a separator. The maximum cross-sectional height (Rt) of the heat-expandable pressure-sensitive adhesive layer surface of the heat-peelable pressure-sensitive adhesive sheet A was 4.5 μm.

(Production Example 2)
A heat-peelable pressure-sensitive adhesive sheet B was obtained by performing the same operation as in Production Example 1 except that the maximum cross-sectional height of the unevenness provided on the separator surface was 12.3 μm. The maximum cross-sectional height (Rt) of the surface of the heat-expandable pressure-sensitive adhesive layer of the heat-peelable pressure-sensitive adhesive sheet B was 11.6 μm.

(Production Example 3)
A heat-peelable pressure-sensitive adhesive sheet C was obtained by performing the same operation as in Production Example 1 except that the separator was not subjected to the sandblasting method. The maximum cross-sectional height (Rt) of the surface of the heat-peelable pressure-sensitive adhesive sheet C was 0.2 μm.

Example 1
The adherend was fixed using the heat-peelable pressure-sensitive adhesive sheet A obtained in Production Example 1, and the adherend was diced. A semiconductor encapsulating resin (size: 50 × 50 mm, thickness: 2 mm, maximum surface roughness of the adherend surface (encapsulating resin surface): 15 μm) was used as the adherend and diced into a 4 × 4 mm chip size. . After completion of dicing, the heat-peelable pressure-sensitive adhesive sheet A was heat-treated with a hot plate (90 ° C. × 1 minute), and the semiconductor chip was peeled off from the pressure-sensitive adhesive sheet. Evaluate whether or not chip jumping occurs during dicing as a ratio of the number of chip jumps to the total number of chips, and determine whether or not the chips are peeled off favorably by heat treatment. Evaluated as a percentage. The results are shown in Table 1.

(Example 2)
Dicing was performed by the same operation as in Example 1 except that the heat-peelable pressure-sensitive adhesive sheet B was used instead of the heat-peelable pressure-sensitive adhesive sheet A, and the same operation as in Example 1 was performed. The results are shown in Table 1.

(Comparative Example 1)
Dicing was performed by the same operation as in Example 1 except that the heat-peelable pressure-sensitive adhesive sheet C was used instead of the heat-peelable pressure-sensitive adhesive sheet A, and the same operation as in Example 1 was performed. The results are shown in Table 1.

It is a schematic sectional drawing which shows an example of the heat-peeling type adhesive sheet used by this invention. It is a schematic sectional drawing which shows an example of the heat-peeling type adhesive sheet used by this invention.

Explanation of symbols

1: Base material 2: Rubbery organic elastic layer 3: Thermally expandable adhesive layer 4: Separator

Claims (4)

  An adherend processing method for processing an adherend using a heat-peelable pressure-sensitive adhesive sheet comprising a heat-expandable pressure-sensitive adhesive layer containing heat-expandable microspheres on at least one surface of a substrate, The relationship between the maximum cross-sectional height Rt of the thermally expandable adhesive layer surface and the maximum cross-sectional height Rt ′ of the adherend surface satisfies Rt ′ ≧ Rt, and Rt is in the range of 0.5 to 12 μm. A method for processing an adherend.   The method for processing an adherend according to claim 1, wherein a heat-peelable pressure-sensitive adhesive sheet having a rubbery organic elastic layer between the substrate and the thermally expandable pressure-sensitive adhesive layer is used as the heat-peelable pressure-sensitive adhesive sheet.   The method for processing an adherend according to claim 2, wherein the rubbery organic elastic layer is made of an adhesive substance.   A method of manufacturing a semiconductor chip by processing a semiconductor substrate using a heat-peelable pressure-sensitive adhesive sheet comprising a heat-expandable pressure-sensitive adhesive layer containing heat-expandable microspheres on at least one surface of a substrate, The relationship between the maximum cross-sectional height Rt of the surface of the thermally expandable adhesive layer and the maximum cross-sectional height Rt ″ of the semiconductor substrate surface satisfies Rt ″ ≧ Rt, and Rt is in the range of 0.5 to 12 μm. A method for manufacturing a semiconductor chip.

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