JP3804805B2 - Heat release type adhesive sheet - Google Patents

Description

  The present invention relates to a heat-peelable pressure-sensitive adhesive sheet that can be easily peeled off from an adherend by a short-time heat treatment at any time.

  Conventionally, there has been known a heat-peelable pressure-sensitive adhesive sheet in which a pressure-sensitive adhesive layer containing a foaming agent such as thermally expandable microspheres or an expanding agent is provided on a substrate (Japanese Patent Publication No. 50-13878, Japanese Patent Publication No. 51). No. 24534, JP-A 56-61468, JP-A 56-61469, JP-A 60-252681, etc.). This heat-peelable pressure-sensitive adhesive sheet is a pressure-sensitive adhesive sheet that achieves both adhesiveness and peelability after use. Adhesion is reduced by foaming or expanding a foaming agent or the like by heating, making it easier than the adherend. It has the characteristic that it can peel. For this reason, it is used as a temporary fixing means or a recycling label in the manufacturing process of electronic parts.

  In recent years, electronic devices have been made lighter, thinner, smaller and lighter, and along with this, electronic components such as capacitors and LEDs are also becoming smaller and chips. The above heat-peelable pressure-sensitive adhesive sheet is also used for temporary fixing at the time of cutting of these electronic components. However, since the area to be bonded per chip decreases as the size is reduced, the pressure-sensitive adhesive sheet It is important to secure an effective contact area with the chip as a countermeasure against defects such as chip skipping and chipping. However, in the conventional heat-peelable pressure-sensitive adhesive sheet, since there are not a few irregularities due to relatively large particles among the thermally expandable microspheres added to the pressure-sensitive adhesive layer surface, In some cases, an effective bonding area could not be secured, and chip skipping or chipping might occur.

Japanese Patent Publication No. 50-13878 Japanese Patent Publication No.51-24534 JP-A-56-61468 JP-A-56-61469 JP 60-252681 A

  Accordingly, an object of the present invention is to provide a heat-peelable pressure-sensitive adhesive sheet that can secure an effective contact area and prevent the occurrence of adhesion defects such as chip jumping even when the adhesion target area of the adherend is small. There is to do.

  As a result of intensive studies to achieve the above object, the present inventors have determined that when the center line average roughness of the surface of the heat-expandable adhesive layer before heating is set to a specific range, adhesion such as chip jumping associated with downsizing of the chip The inventors found that defects can be suppressed and completed the present invention.

That is, the present invention is a method for producing 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 side of a substrate, ≧ maximum particle diameter of thermally expandable microspheres in the thermally expandable adhesive layer ”, and the thickness of the thermally expandable adhesive layer and the particle diameter of the thermally expandable microspheres added to the thermally expandable adhesive layer To obtain a heat-peelable pressure-sensitive adhesive sheet having a center line average roughness of 0.4 μm or less on the surface of the heat-expandable pressure-sensitive adhesive layer before heating. Provided is a method for producing a heat-peelable pressure-sensitive adhesive sheet for temporary fixing during component cutting .

  According to the heat-peelable pressure-sensitive adhesive sheet of the present invention, even when the adhesion target area of an adherend such as a chip is small, an effective contact area can be ensured, and the occurrence of adhesion failure such as chip jumping can be prevented. be able to.

  Embodiments of the present invention will be described below in detail with reference to the drawings as necessary. FIG. 1 is a schematic cross-sectional view showing an example of the heat-peelable pressure-sensitive adhesive sheet of the present invention, and FIG. 2 is a schematic cross-sectional view showing another example of the heat-peelable pressure-sensitive adhesive sheet of the present invention.

  In the example of FIG. 1, a heat-expandable pressure-sensitive adhesive layer 3 is provided on one surface of a substrate 1, and a separator 4 is laminated thereon. In the example of FIG. 2, a heat-expandable adhesive layer 3 is provided on one surface of the substrate 1 via a rubbery organic elastic layer 2, and a separator 4 is further laminated thereon.

  The base material 1 is a support base for the heat-expandable adhesive layer 3 and the like, and plastic films and sheets are generally used. However, paper, cloth, nonwoven fabric, metal foil, etc., or a laminate of these and plastic An appropriate thin leaf body such as a laminate of plastic films (or sheets) can be used. The thickness of the substrate 1 is generally 500 μm or less, preferably 1 to 300 μm, more preferably about 5 to 250 μm, but is not limited thereto. The surface of the substrate 1 is chemically treated by conventional surface treatments such as chromic acid treatment, ozone exposure, flame exposure, high piezoelectric impact exposure, ionizing radiation treatment, etc., in order to improve the adhesion to the thermally expandable adhesive layer 3 and the like. Alternatively, it may be subjected to an oxidation treatment by a physical method, and in order to impart releasability from the heat-expandable adhesive layer 3 or the like, for example, coating with a release agent such as a silicone resin or a fluorine resin Processing may be performed.

  The substrate 1 includes a low adhesion substrate and a strong adhesion substrate. Examples of the low-adhesive substrate include a substrate made of a nonpolar polymer such as an olefin resin such as polyethylene and polypropylene, and a substrate whose surface is coated with the release agent. Examples of the strong adhesive substrate include a substrate made of a highly polar polymer such as polyester, and a substrate whose surface has been subjected to an oxidation treatment or the like by the chemical or physical method.

  The low-adhesive base material is used as a base material for a base-peelable pressure-sensitive adhesive sheet from which the base material and the layer on the base material can be easily peeled off. For example, after the base material release type adhesive sheet is attached to one adherend a, the base material is peeled off to leave the thermally expandable adhesive layer on the adherend a, It can be used as a temporary fixing adhesive such as bonding the adherend b. In this case, when it is desired to release the bonded state, the adherends a and b can be easily separated by heat treatment. On the other hand, the strongly adhesive substrate is used as a substrate for a substrate-fixed adhesive sheet in which a substrate and a layer on the substrate are strongly bonded. In such a substrate-fixed pressure-sensitive adhesive sheet, it can be adhered to an adherend with a predetermined adhesive force during adhesion, and can be easily peeled or separated by heat treatment when it is desired to release the adhesion state.

  The rubber-like organic elastic layer 2 has a function of increasing the adhesion area by causing the surface of the pressure-sensitive adhesive sheet to follow the surface shape of the adherend when the heat-peelable pressure-sensitive adhesive sheet is bonded to the adherend. When the pressure-sensitive adhesive sheet is heated and peeled off from the adherend, the heat expansion of the heat-expandable layer is controlled to a high degree (accurately), and the heat-expandable layer is expanded preferentially and uniformly in the thickness direction. With functions.

  In order to provide the rubbery organic elastic layer 2, for example, natural rubber, synthetic rubber, or synthetic resin having rubber elasticity having a D-type Sure D-type hardness of 50 or less, particularly 40 or less based on ASTM D-2240. It is preferable to form by.

  Examples of the synthetic rubber or the synthetic resin having rubber elasticity include nitrile-based, diene-based, and acrylic-based synthetic rubbers; polyolefin-based and polyester-based thermoplastic elastomers; ethylene-vinyl acetate copolymer, polyurethane, polybutadiene, and the like. And a synthetic resin having rubber elasticity such as soft polyvinyl chloride. Even if it is essentially a hard polymer such as polyvinyl chloride, rubber elasticity can be manifested in combination with compounding agents such as plasticizers and softeners. Such a composition can also be used as a constituent material of the rubbery organic elastic layer. In addition, an adhesive substance such as an adhesive constituting the later-described thermally expandable adhesive layer 3 can be preferably used as a constituent material of the rubbery organic elastic layer 2.

  The thickness of the rubbery organic elastic layer 2 is generally 500 μm or less (for example, 1 to 500 μm), preferably 3 to 300 μm, and more preferably about 5 to 150 μm.

  The rubber-like organic elastic layer 2 is formed, for example, by applying a coating liquid containing an elastic layer forming material such as natural rubber, synthetic rubber or synthetic resin having rubber elasticity on the substrate 1 (coating method), A method in which a film made of an elastic layer forming material or a laminated film in which a layer made of the elastic layer forming material is previously formed on one or more thermally expandable adhesive layers 3 is bonded to the substrate 1 (dry laminating method), The resin composition containing the constituent material of the material 1 and the resin composition containing the elastic layer forming material can be co-extruded (co-extrusion method).

  The rubbery organic elastic layer 2 may be formed of a sticky substance mainly composed of natural rubber, synthetic rubber, or synthetic resin having rubber elasticity, and may be a foam film or the like mainly composed of such a component. It may be formed. Foaming is a conventional method, for example, a method using mechanical stirring, a method using a reaction product gas, a method using a foaming agent, a method for removing soluble substances, a method using a spray, a method for forming a syntactic foam, It can be performed by a sintering method or the like. The rubbery organic elastic layer 2 may be a single layer or may be composed of two or more layers.

  The heat-expandable pressure-sensitive adhesive layer 3 includes a pressure-sensitive adhesive for imparting tackiness and a heat-expandable microsphere (microcapsule) for imparting heat-expandability. Therefore, after the adhesive sheet is attached to the adherend, the thermally expandable adhesive layer 3 is heated at any time to foam and / or expand the thermally expandable microspheres, whereby the thermally expandable adhesive layer The adhesion area of 3 and a to-be-adhered body can be reduced, and an adhesive sheet can be peeled easily. With a foaming agent that is not microencapsulated, good peelability cannot be stably exhibited.

  The pressure-sensitive adhesive is preferably one that does not restrain foaming and / or expansion of the thermally expandable microspheres as much as possible during heating. Examples of the pressure sensitive adhesive include rubber pressure sensitive adhesive, acrylic pressure sensitive adhesive, vinyl alkyl ether pressure sensitive adhesive, silicone pressure sensitive adhesive, polyester pressure sensitive adhesive, polyamide pressure sensitive adhesive, urethane pressure sensitive adhesive, and styrene-diene block copolymer. One or a combination of two or more known pressure-sensitive adhesives such as system pressure-sensitive adhesives and those having a melting point of about 200 ° C. or less and a melt-melting resin having a melting point of about 200 ° C. or less can be used. (See, for example, JP-A-56-61468, JP-A-61-174857, JP-A-63-17981, JP-A-56-13040, etc.). In addition to the adhesive component (base polymer), the adhesive is a crosslinking agent (eg, polyisocyanate, alkyl etherified melamine compound, etc.), tackifier (eg, rosin derivative resin, polyterpene resin, petroleum resin, oil-soluble phenol) Resin, etc.), plasticizers, fillers, anti-aging agents and other suitable additives may be included.

In general, the pressure-sensitive adhesive is a rubber-based pressure-sensitive adhesive based on natural rubber or various synthetic rubbers; (meth) acrylic acid alkyl esters (for example, methyl ester, ethyl ester, propyl ester, isopropyl ester, butyl ester, Isobutyl ester, s-butyl ester, t-butyl ester, pentyl ester, hexyl ester, heptyl ester, octyl ester, 2-ethylhexyl ester, isooctyl ester, isodecyl ester, dodecyl ester, tridecyl ester, pentadecyl ester, hexa decyl ester, heptadecyl ester, octadecyl ester, nonadecyl ester, Accession used as monomer components one or more of C, such as _1-20 alkyl ester) such as eicosyl ester Such as acrylic adhesive is used to Le-based polymer (homopolymer or copolymer) as a base polymer.

  The acrylic polymer may be mixed with other monomer components copolymerizable with the (meth) acrylic acid alkyl ester as necessary for the purpose of modifying cohesion, heat resistance, crosslinkability, and the like. Corresponding units may be included. Examples of such monomer components 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 Acid anhydride monomers such as hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, hydroxyhexyl (meth) acrylate, hydroxyoctyl (meth) acrylate, (meth) Hydroxyl group-containing monomers such as hydroxydecyl acrylate, hydroxylauryl (meth) acrylate, (4-hydroxymethylcyclohexyl) methyl methacrylate; styrene sulfonic acid, allyl sulfonic acid, 2- (meth) acrylic Sulfonic acid group-containing monomers such as mid-2-methylpropanesulfonic acid, (meth) acrylamidepropanesulfonic acid, sulfopropyl (meth) acrylate, (meth) acryloyloxynaphthalenesulfonic acid; (meth) acrylamide, 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 aminoalkyl monomers such as N, N-dimethylaminoethyl acrylate, t-butylaminoethyl (meth) acrylate; methoxyethyl (meth) acrylate, ethoxyethyl (meth) acrylate, etc. (Meta) Acry Acid alkoxyalkyl monomers; maleimide monomers such as N-cyclohexylmaleimide, N-isopropylmaleimide, N-laurylmaleimide, N-phenylmaleimide; N-methylitaconimide, N-ethylitaconimide, N-butylitaconimide, N -Itacimide monomers such as octylitaconimide, N-2-ethylhexylitaconimide, N-cyclohexylitaconimide, N-laurylitaconimide; N- (meth) acryloyloxymethylenesuccinimide, N- (meth) acryloyl-6-oxy Succinimide monomers such as hexamethylene succinimide and N- (meth) acryloyl-8-oxyoctamethylene succinimide; vinyl acetate, vinyl propionate, N-vinyl pyrrolide , 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-methyl styrene, N-vinyl Vinyl monomers such as caprolactam; cyanoacrylate monomers such as acrylonitrile and methacrylonitrile; epoxy group-containing acrylic monomers such as glycidyl (meth) acrylate; polyethylene glycol (meth) acrylate, polypropylene glycol (meth) acrylate, ( Glycol acrylic ester monomers such as (meth) acrylic acid methoxyethylene glycol and (meth) acrylic acid methoxypolypropylene glycol; Acrylic acid ester monomers having heterocycles such as tetrahydrofurfuryl acrylate, fluorine (meth) acrylate, silicone (meth) acrylate, halogen atoms, silicon atoms, etc .; 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) acrylate, Polyfunctional monomers such as dipentaerythritol hexa (meth) acrylate, epoxy acrylate, polyester acrylate, urethane acrylate; isoprene, butadiene, iso Examples thereof include olefin monomers such as butylene; vinyl ether monomers such as vinyl ether. These monomer components can be used alone or in combination of two or more.

In addition, from the point of balance of moderate adhesive force before heat treatment and lowering of adhesive force after heat treatment, more preferable pressure-sensitive adhesives have a dynamic elastic modulus of 50,000 to 10,000,000 dyn / cm from room temperature to 150 ° C. ^A pressure sensitive adhesive based on polymers in the range of ² .

  The heat-expandable microsphere may be a microsphere in which a substance that easily expands by gasification by heating, such as isobutane, propane, or pentane, is encapsulated in an elastic shell. The shell is often formed of a hot-melt material or a material that is destroyed by thermal expansion. Examples of the substance forming the shell include vinylidene chloride-acrylonitrile copolymer, polyvinyl alcohol, polyvinyl butyral, polymethyl methacrylate, polyacrylonitrile, polyvinylidene chloride, and polysulfone. Thermally expandable microspheres can be produced by a conventional method such as a coacervation method or an interfacial polymerization method. Examples of the thermally expandable microsphere include a commercially available product such as a microsphere [trade name, manufactured by Matsumoto Yushi Seiyaku Co., Ltd.].

  In order to efficiently reduce the adhesive force of the pressure-sensitive adhesive layer by heat treatment, thermally expandable microspheres having an appropriate strength that does not rupture until the volume expansion coefficient is 5 times or more, especially 7 times or more, particularly 10 times or more are preferable. .

  The blending amount of the thermally expandable microspheres can be appropriately set according to the expansion ratio of the adhesive layer, the lowering of the adhesive force, etc., but generally the amount is 100 parts by weight of the base polymer forming the thermally expandable adhesive layer 3. For example, it is 1-150 weight part, Preferably it is 10-130 weight part, More preferably, it is 25-100 weight part.

  For the heat-expandable pressure-sensitive adhesive layer 3, for example, a coating liquid containing a pressure-sensitive adhesive and heat-expandable microspheres is prepared using a solvent as necessary, and this is applied onto the substrate 1 or the rubbery organic elastic layer 2. A method, a method in which the coating liquid is applied on an appropriate separator (such as release paper) to form a thermally expandable adhesive layer, and this is transferred (transferred) onto the substrate 1 or the rubbery organic elastic layer 2. Can be formed by conventional methods. The thermally expandable pressure-sensitive adhesive layer 3 may be either a single layer or multiple layers.

  An important feature of the present invention is that the center line average roughness of the surface of the thermally expandable pressure-sensitive adhesive layer before heating is 0.4 μm or less (for example, about 0.02 to 0.4 μm). The center line average roughness is preferably 0.3 μm or less (for example, about 0.02 to 0.3 μm), more preferably 0.2 μm or less (for example, about 0.02 to 0.2 μm). The maximum roughness of the surface of the thermally expandable pressure-sensitive adhesive layer before heating is preferably 5 μm or less (for example, about 0.1 to 5 μm), more preferably 3 μm or less (for example, about 0.5 to 3 μm). is there.

  The centerline average roughness and maximum roughness of the surface of the thermally expandable adhesive layer before heating are appropriately selected from the thickness of the thermally expandable adhesive layer 3 and the particle size of the thermally expandable microspheres added to the adhesive layer. Can be adjusted.

  The particle diameter of the heat-expandable microspheres is ensured such that the centerline average roughness of the surface of the heat-expandable adhesive layer before heating is 0.4 μm or less, and further the maximum roughness of the surface of the heat-expandable pressure-sensitive adhesive layer before heating is 5 μm or less. Therefore, the relationship of “thickness of thermally expandable pressure-sensitive adhesive layer 3 ≧ particle diameter of thermally expandable microspheres” is desirable. When the particle size of the thermally expandable microsphere is larger than the thickness of the thermally expandable pressure-sensitive adhesive layer 3, the surface roughness of the heat-expandable pressure-sensitive adhesive layer 3 increases, and the effective adhesion area with the adherend decreases. When the rubber-like organic elastic layer 2 is provided between the base material 1 and the heat-expandable pressure-sensitive adhesive layer 3, the particle diameter of the heat-expandable microsphere is slightly larger than the thickness of the heat-expandable pressure-sensitive adhesive layer 3. However, this is not the case because an absorption effect on the rubber-like organic elastic layer 2 can be expected. The particle size adjustment of the thermally expandable microspheres may be performed during the process of generating the thermally expandable microspheres, or may be performed by means such as classification after the generation.

  The thickness of the heat-expandable pressure-sensitive adhesive layer 3 is preferably 300 μm or less, particularly preferably 100 μm or less. If the thickness is excessive, cohesive failure occurs at the time of peeling after the heat treatment, the adhesive remains on the adherend, and the adherend tends to be contaminated. On the other hand, if the thickness of the pressure-sensitive adhesive is too small, the degree of deformation of the heat-expandable pressure-sensitive adhesive layer 3 due to heat treatment is small, and the adhesive force is difficult to decrease smoothly, or the particle diameter of the heat-expandable microspheres to be added is excessively increased. It is necessary to make it smaller. From this point, the thickness of the thermally expandable pressure-sensitive adhesive layer 3 is preferably 5 μm or more, more preferably 10 μm or more, and particularly preferably 15 μm or more.

  As the separator 4, a conventional release paper or the like can be used. The separator 4 is used as a protective material for the heat-expandable pressure-sensitive adhesive layer 3, and is peeled off when the pressure-sensitive adhesive sheet is attached to an adherend. The separator 4 is not necessarily provided.

  The thermally expandable pressure-sensitive adhesive layer 3 can be formed not only on one side of the substrate 1 but also on both sides. Moreover, the rubber-like organic elastic layer 2 can also be interposed on one side or both sides of the substrate 1 as necessary. Furthermore, the heat-expandable pressure-sensitive adhesive layer 3 can be provided on one surface of the substrate 1, and a normal adhesive layer that does not contain heat-expandable microspheres can be provided on the other surface. An intermediate layer such as an undercoat layer or an adhesive layer may be provided between the base material 1 and the rubbery organic elastic layer 2 or between the rubbery organic elastic layer 2 and the heat-expandable pressure-sensitive adhesive layer 3.

  In the heat-peelable pressure-sensitive adhesive sheet of the present invention, since the center average roughness of the surface of the heat-expandable pressure-sensitive adhesive layer before heating is small, for example, it is used as a temporary fixing tape when cutting electronic components and is bonded when making smaller chips. Even when the target area is small, an effective contact area with the work can be sufficiently ensured, so that it is possible to suppress the occurrence of defects due to insufficient adhesive force such as chip fly and displacement. Therefore, it is possible to prevent a decrease in productivity, yield, and the like.

  Further, in the heat-peelable pressure-sensitive adhesive sheet in which the rubber-like organic elastic layer is provided between the base material and the thermally expandable pressure-sensitive adhesive layer, the elasticity of the rubber-like organic elastic layer is required when the pressure-sensitive adhesive sheet is bonded to the adherend. As a result, the surface of the pressure-sensitive adhesive sheet satisfactorily follows the surface shape of the adherend, so that a large adhesion area can be obtained, and the adhesive strength can be increased. (Change) can be controlled with high precision, and can be uniformly expanded in preference to the thickness direction, and peeling becomes easier. Moreover, even if the particle size of the thermally expandable microspheres contained in the thermally expandable adhesive layer is somewhat large, the unevenness resulting therefrom is absorbed by the rubber-like organic elastic layer, so that the surface roughness of the thermally expandable adhesive layer is reduced. Can be kept small.

  The heat-peelable pressure-sensitive adhesive sheet of the present invention can be used for applications in which an adherend made of an appropriate article is permanently bonded, but after adhering the adherend for a predetermined period and achieving the bonding purpose Is suitably used for applications where it is required or desired to release the adhesive state. In particular, it is most suitable for the manufacture of smaller chip components that are difficult to bond with conventional heat-peelable pressure-sensitive adhesive sheets, for example, for the process of making smaller chips for electronic components such as semiconductor wafers, chips, ceramic capacitors, and oscillators.

  The heat treatment conditions for allowing the pressure-sensitive adhesive sheet of the present invention to be easily peeled off from the adherend include the reduction in the adhesion area due to the surface state of the adherend and the type of thermally expandable microspheres, the substrate and the covering. It can be appropriately set depending on conditions such as the heat resistance of the adherend and the heating method. General heat treatment conditions are a temperature of 100 to 250 ° C. and a time of 1 to 90 seconds (hot plate or the like) or 5 to 15 minutes (hot air dryer or the like). Under such heating conditions, the heat-expandable microspheres of the pressure-sensitive adhesive layer usually expand and / or foam and the pressure-sensitive adhesive layer expands and deforms, and the adhesive force is reduced or lost. Note that the heat treatment can be performed at an appropriate stage depending on the purpose of use. In some cases, an infrared lamp or heated water can be used as the heating source.

  Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples. The particle size measurement was performed using a laser scattering / diffraction particle size distribution analyzer SALD-2000J (manufactured by Shimadzu Corporation).

Example 1
Thermally expandable microspheres A (Matsumoto Microsphere F-50D: Matsumoto Yushi Seiyaku Co., Ltd .: average particle size 13.4 μm, maximum particle size 63 μm) are classified using a centrifugal force classifier, and classified heat Expandable microspheres B (average particle size 12.3 μm, maximum particle size 42 μm) were obtained.
On the other hand, 2-ethylhexyl acrylate-ethyl acrylate-methyl methacrylate (30 parts by weight-70 parts by weight-5 parts by weight) copolymer-based pressure-sensitive adhesive 100 parts by weight (containing 2 parts by weight of a polyurethane-based crosslinking agent) Prepare a toluene solution containing 30 parts by weight of classified thermally expandable microspheres B, apply this onto a 100 μm thick polyester film, dry it to a thickness of 45 μm, dry it, and heat peel A mold pressure-sensitive adhesive sheet was obtained.
Next, a 120 mm × 100 mm × 0.5 mm thick ceramic sheet (before firing) is temporarily fixed to the adhesive surface of the heat-peelable adhesive sheet, and the ceramic sheet is attached and fixed to a dicing ring, through a rotary blade, 0 Full cut into 6 mm × 0.3 mm chips. After the cutting, a heat treatment at 130 ° C. for 60 seconds was performed on a hot plate while being attached and fixed to the dicing ring, and after cooling, the chip was collected by inverting vibration.

Reference example 1
On a polyester film having a thickness of 100 μm, a toluene solution containing 2-ethylhexyl acrylate-ethyl acrylate-methyl methacrylate copolymer pressure sensitive adhesive (containing 1 part by weight of a polyurethane-based cross-linking agent) has a thickness after drying. The rubber-like organic elastic layer was formed by applying and drying to a thickness of 10 μm.
In the same manner as in Example 1, 100 parts by weight of 2-ethylhexyl acrylate-ethyl acrylate-methyl methacrylate copolymer pressure-sensitive adhesive (containing 2 parts by weight of a polyurethane-based crosslinking agent) and classified thermally expandable microspheres B30 A toluene solution prepared by blending parts by weight was prepared, and this was coated on the separator so that the thickness after drying was 35 μm, dried to form an adhesive layer, and then the rubbery organic elastic layer was formed. The polyester film was bonded to the rubbery organic elastic layer side to obtain a heat-peelable pressure-sensitive adhesive sheet.
Next, a 120 mm × 100 mm × 0.5 mm thick ceramic sheet (before firing) is temporarily fixed to the adhesive surface of the heat-peelable adhesive sheet, and the ceramic sheet is attached and fixed to a dicing ring, through a rotary blade, 0 Full cut into 6 mm × 0.3 mm chips. After the cutting, a heat treatment at 130 ° C. for 60 seconds was performed on a hot plate while being attached and fixed to the dicing ring, and after cooling, the chip was collected by inverting vibration.

Example 2
Instead of classified thermally expandable microspheres B, thermally expandable microspheres C (Matsumoto Microsphere F-301D: manufactured by Matsumoto Yushi Seiyaku Co., Ltd .: average particle size 11.6 μm, maximum particle size 42 μm) are added to the adhesive layer In addition, the same operation as in Example 1 was performed except that the heat treatment condition after cutting the chip was set to 100 ° C. × 60 seconds.

Comparative Example 1
Instead of classified thermally expandable microspheres B, thermally expandable microspheres A (Matsumoto Microsphere F-50D: manufactured by Matsumoto Yushi Seiyaku Co., Ltd .: average particle size 13.4 μm, maximum particle size 63 μm) are added to the adhesive layer Except that, the same operation as in Example 1 was performed.

Comparative Example 2
Instead of classified thermally expandable microspheres B, thermally expandable microspheres A (Matsumoto Microsphere F-50D: manufactured by Matsumoto Yushi Seiyaku Co., Ltd .: average particle size 13.4 μm, maximum particle size 63 μm) are added to the adhesive layer The same operation as in Reference Example 1 was performed except that.

Evaluation Test Table 1 shows the centerline average roughness and maximum roughness of the pressure-sensitive adhesive layer surface before heating of the pressure-sensitive adhesive sheets obtained in Examples and Comparative Examples, and the chip retention rate at the time of chip cutting. The center line average roughness and maximum roughness of the adhesive layer surface were measured with a non-contact three-dimensional surface roughness meter manufactured by ZYGO. In either case of the example or the comparative example, no adhesive residue was observed on the chip peeling surface after heat peeling recovery.

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

Explanation of symbols

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

Claims (7)

A method for producing 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 side of a substrate , wherein “the thickness of the heat-expandable pressure-sensitive adhesive layer ≧ the heat-expandable pressure-sensitive adhesive layer” Adjusting the thickness of the heat-expandable adhesive layer and the particle diameter of the heat-expandable microspheres added to the heat-expandable adhesive layer so that the maximum particle diameter of the heat-expandable microspheres in the layer is reached. Temporary fixing at the time of cutting an electronic component, characterized in that a heat-peelable pressure-sensitive adhesive sheet having a center line average roughness of 0.4 μm or less on the surface of the heat-expandable pressure-sensitive adhesive layer before heating is obtained by forming an expandable pressure-sensitive adhesive layer Of manufacturing a heat-peelable pressure-sensitive adhesive sheet . The method for producing a heat-peelable pressure-sensitive adhesive sheet for temporarily fixing when cutting an electronic component according to claim 1, wherein the particle size of the thermally expandable microsphere is adjusted by classification. The method for producing a heat-peelable pressure-sensitive adhesive sheet for temporary fixing at the time of cutting an electronic component according to claim 2, wherein the classification is performed using a centrifugal air classifier. The method for producing a heat-fixable pressure-sensitive adhesive sheet for temporary fixing at the time of cutting an electronic component according to any one of claims 1 to 3, wherein a base material that has been surface-treated is used as the base material. The heat-peelable pressure-sensitive adhesive sheet for temporary fixing at the time of cutting an electronic component according to any one of claims 1 to 4, wherein a heat-peelable pressure-sensitive adhesive sheet having a surface roughness of 5 µm or less is obtained. Manufacturing method. The method for producing a heat-fixable pressure-sensitive adhesive sheet for temporary fixing at the time of cutting an electronic component according to any one of claims 1 to 5, wherein a rubbery organic elastic layer is provided between the base material and the thermally expandable pressure-sensitive adhesive layer. The method for producing a heat-fixable pressure-sensitive adhesive sheet for temporary fixing at the time of cutting an electronic component according to claim 6, wherein the rubbery organic elastic layer is formed of an adhesive substance.

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