WO2014142193A1

WO2014142193A1 - Adhesive sheet

Info

Publication number: WO2014142193A1
Application number: PCT/JP2014/056549
Authority: WO
Inventors: 高正平山; 和寛北山
Original assignee: 日東電工株式会社
Priority date: 2013-03-15
Filing date: 2014-03-12
Publication date: 2014-09-18
Also published as: TW202024263A; CN105073929A; KR102207511B1; KR20150127087A; JPWO2014142193A1; CN113652174A; TW201443192A

Abstract

Provided is an adhesive sheet which is able to realize excellent cutting precision and a reduction in cutting debris when cutting microcomponents such as electronic components. This adhesive sheet is provided only on one side with an adhesive surface in which the adhesive strength decreases when heated, with the elastic modulus of the surface on the opposite side of the adhesive surface measured by nanoindentation being at least 1 MPa. In a preferred embodiment, the sheet is provided with an adhesive region having the adhesive surface as one surface thereof and a coating region which abuts the side of the adhesive region opposite the adhesive surface in a cross-sectional view, with the adhesive region including an adhesive and thermally expandable microspheres.

Description

Adhesive sheet

The present invention relates to an adhesive sheet.

In the manufacture of electronic components such as silicon wafers, multilayer capacitors, and transparent electrodes, it is necessary to reduce the size of a substrate obtained by creating necessary functions in a large area to a desired size by cutting. Is called. At the time of cutting, a pressure-sensitive adhesive sheet for fixing a workpiece (substrate) for preventing a reduction in cutting accuracy due to stress and vibration during processing is used. The pressure-sensitive adhesive sheet is required to have a sufficient adhesive force with respect to the workpiece during processing, and after processing, it is required that the cut workpiece (electronic component) can be easily peeled off. As such an adhesive sheet, an adhesive sheet containing thermally expandable microspheres in an adhesive is known (for example, Patent Document 1). The pressure-sensitive adhesive sheet containing the heat-expandable microspheres exhibits sufficient pressure-sensitive adhesive force during the above-mentioned processing because the heat-expandable microspheres are expanded by heating or foamed to reduce the pressure-sensitive adhesive force. Thus, the electronic component can be easily peeled off.

In recent years, electronic parts have been reduced in weight and size, and pressure-sensitive adhesive sheets for fixing a workpiece capable of realizing cutting with higher accuracy have been demanded. Moreover, reduction of the processing waste (cutting waste) produced at the time of a cutting process is also calculated | required. In response to these requirements, it is considered that a pressure-sensitive adhesive sheet that can achieve higher cutting accuracy and reduced cutting waste can be obtained if the pressure-sensitive adhesive constituting the pressure-sensitive adhesive sheet is thinned. However, the pressure-sensitive adhesive sheet containing thermally expandable microspheres has a problem that the thickness of the adhesive is restricted because it contains thermally expandable microspheres. More specifically, in the pressure-sensitive adhesive sheet containing thermally expandable microspheres, if the adhesive is thinned, the thermally expandable microspheres protrude from the adhesive, which is inferior in adhesion to the base material or processing base. There is a problem that the remarkably decreases.

JP 2002-121510 A

The present invention has been made in order to solve the above-described conventional problems, and an object of the present invention is to realize excellent cutting accuracy and reduction of cutting waste when cutting a small part such as an electronic part. It is to provide an adhesive sheet.

The pressure-sensitive adhesive sheet of the present invention has a pressure-sensitive adhesive surface whose adhesive strength is reduced by heating only on one side, and the elastic modulus by a nanoindentation method at 25 ° C. of the surface opposite to the pressure-sensitive adhesive surface is 1 MPa or more. .
In a preferred embodiment, in a cross-sectional view, the pressure-sensitive adhesive region includes the pressure-sensitive adhesive surface as a surface, and a covering material region adjacent to the pressure-sensitive adhesive region on the side opposite to the pressure-sensitive adhesive surface. , Including an adhesive and thermally expandable microspheres.
In preferable embodiment, the thickness of the said adhesive area | region is 50 micrometers or less.
In preferable embodiment, the adhesive force at the time of sticking the said adhesive surface side to a polyethylene terephthalate film is 0.2 N / 20mm or more.
In a preferred embodiment, in the pressure-sensitive adhesive sheet of the present invention, the ratio (a2 / a1) of the pressure-sensitive adhesive force (a1) before heating to the pressure-sensitive adhesive force (a2) after heating is 0.0001 to 0.5. .
In a preferred embodiment, the surface roughness Ra of the adhesive surface after heating is 3 μm or more.
In preferable embodiment, a base material is further provided on the opposite side to the said adhesive surface.
According to another aspect of the present invention, a method for manufacturing an electronic component is provided. This manufacturing method includes cutting the electronic component material after attaching the electronic component material on the pressure-sensitive adhesive sheet.

According to the present invention, it has a pressure-sensitive adhesive surface whose adhesive strength is reduced by heating, and the elastic modulus of the surface opposite to the pressure-sensitive adhesive surface is relatively high. An adhesive sheet capable of realizing excellent cutting accuracy can be obtained. More specifically, in the present invention, a pressure-sensitive adhesive region including a pressure-sensitive adhesive and thermally expandable microspheres and having a pressure-sensitive adhesive surface as a surface is formed, and the pressure-sensitive adhesive region on the side opposite to the pressure-sensitive adhesive surface is relatively high. Low elastic region without influence of irregularities due to thermally expandable microspheres protruding from the adhesive region by forming an elastic coating material region and embedding the thermally expandable microspheres protruding from the adhesive region into the coating material region As a result, a pressure-sensitive adhesive sheet capable of realizing excellent cutting accuracy can be obtained. In addition, according to the present invention, since the pressure-sensitive adhesive region can be made thin, the generation of cutting waste can be suppressed by performing a cutting process on a micro component such as an electronic component using the pressure-sensitive adhesive sheet of the present invention.

It is a schematic sectional drawing of the adhesive sheet by preferable embodiment of this invention. It is a schematic sectional drawing of the adhesive sheet by another preferable embodiment of this invention. It is a figure which shows the Raman mapping obtained by the measurement of the thickness in Example 3. It is a figure which shows the SEM image of the cross section of the adhesive sheet in Example 11. FIG.

A. 1 is a schematic sectional view of a pressure-sensitive adhesive sheet according to a preferred embodiment of the present invention. The pressure-sensitive adhesive sheet 100 has the pressure-sensitive adhesive surface 11 only on one side thereof. In addition, the pressure-sensitive adhesive sheet 100 has a surface 21 having an elastic modulus of 1 MPa or more at 25 ° C. as a surface 21 opposite to the pressure-sensitive adhesive surface 11. A surface having such an elastic modulus can be formed, for example, by providing a covering material region 20 as described below. The pressure-sensitive adhesive sheet 100 preferably includes thermally expandable microspheres 13 that can expand or foam by heating.

The pressure-sensitive adhesive sheet 100 has a pressure-sensitive adhesive region 10 including a pressure-sensitive adhesive surface 11 as a surface, and a coating material region 20 adjacent to the pressure-sensitive adhesive region 10 opposite to the pressure-sensitive adhesive surface 11. The adhesive region 10 preferably includes an adhesive 12 and thermally expandable microspheres 13. The pressure-sensitive adhesive region 10 refers to a region from the pressure-sensitive adhesive surface 11 to the interface 1 between the pressure-sensitive adhesive 12 constituting the pressure-sensitive adhesive region 10 and the material constituting the coating material region 20. The covering material region 20 is a region from the interface 1 between the adhesive 12 constituting the adhesive region 10 and the material constituting the covering material region 20 to the surface 21 opposite to the adhesive surface 11. The thermally expandable microsphere 13 may protrude from the adhesive region 10 to the covering material region 20. The thermally expandable microspheres 13 protruding from the pressure-sensitive adhesive region 10 can be covered with the covering material region 20, and as a result, the influence of unevenness due to the thermally expandable microspheres 13 can be eliminated. The outer surface (lower surface in the illustrated example) of the covering material region 20 is a surface 21 having an elastic modulus of 1 MPa or more by the nanoindentation method. Although not shown, the adhesive surface 11 may be protected by disposing a release paper outside the adhesive surface 11 until the adhesive sheet is put to practical use. In the illustrated example, the interface 1 is clearly illustrated, but the interface may be an interface that is difficult to distinguish visually or with a microscope. The interface that is difficult to discriminate visually or with a microscope can be discriminated by analyzing the composition of each region (details will be described later).

In the present invention, the thermally expandable microsphere 13 protrudes from the adhesive region 10 by forming the coating material region 20 having an elastic modulus appropriately adjusted on the side opposite to the adhesive surface 11. Allowing the adhesive region 10 to be thinned. If the pressure-sensitive adhesive region 10 which is a low elastic region is thinned, it can contribute to the realization of excellent cutting accuracy as a temporary fixing sheet when cutting an electronic component or the like. More specifically, if an electronic component or the like is cut using a pressure-sensitive adhesive sheet having a thin pressure-sensitive adhesive region 10 as a temporary fixing sheet, the chip after cutting is reattached because the pressure-sensitive adhesive sheet is less deformed. It is possible to prevent the cutting surface from becoming slanted or S-shaped, and preventing chipping during cutting. Moreover, when the adhesive sheet with the thin adhesive area | region 10 is used as a temporary fixing sheet | seat at the time of cutting an electronic component etc., generation | occurrence | production of cutting waste can also be suppressed. The pressure-sensitive adhesive sheet of the present invention has the above-mentioned effect in cutting with a rotary blade frequently used in a dicing process, and also has the above-mentioned effect in cutting with a flat blade adopted to reduce cutting loss. It is particularly useful. Further, even when cutting under heating (for example, 30 ° C. to 150 ° C.), the cutting can be performed with high accuracy as described above.

Moreover, since the heat-expandable microsphere 13 exists in the adhesive surface 11 side (adhesive area | region 10), the adhesive sheet of this invention removes a to-be-adhered body (for example, chip | tip after cutting) from an adhesive sheet. At the time of peeling, by heating at a temperature at which the thermally expandable microspheres 13 can expand or foam, unevenness is generated on the adhesive surface, and the adhesive force of the adhesive surface can be reduced or eliminated.

The adhesive strength when the adhesive surface of the adhesive sheet of the present invention is attached to a polyethylene terephthalate film (for example, thickness 25 μm) is preferably 0.2 N / 20 mm or more, more preferably 0.2 N / 20 mm to 20 N / 20 mm, more preferably 2 N / 20 mm to 10 N / 20 mm. If it is such a range, the adhesive sheet useful as a temporary fixing sheet at the time of cutting an electronic component etc. can be obtained. In the present specification, the adhesion is an adhesion measured by a method according to JIS Z 0237: 2000 (measurement temperature: 23 ° C., bonding condition: 2 kg roller 1 reciprocation, peeling speed: 300 mm / min, peeling angle 180 °). I say power.

The pressure-sensitive adhesive strength of the pressure-sensitive adhesive sheet of the present invention is preferably 0.2 N / 20 mm or less, more preferably 0.1 N / 20 mm, after the pressure-sensitive adhesive surface of the pressure-sensitive adhesive sheet is adhered to a polyethylene terephthalate film (for example, 25 μm thick) and heated. It is as follows. In the present specification, the heating of the pressure-sensitive adhesive sheet refers to heating at a temperature and time at which the heat-expandable microspheres expand or foam and the adhesive force is reduced. The heating is, for example, heating at 70 to 270 ° C. for 1 to 10 minutes.

The adhesive force when adhering the adhesive surface of the adhesive sheet of the present invention to a polyethylene terephthalate film (for example, 25 μm thick) (that is, the adhesive force before heating (a1)) and the adhesive force after heating (a2) The ratio (a2 / a1) is preferably 0.5 or less, more preferably 0.1 or less. The lower limit of (a2 / a1) is preferably 0.0001, and more preferably 0.0005.

As described above, the pressure-sensitive adhesive sheet of the present invention is uneven at the pressure-sensitive adhesive surface when heated at a predetermined temperature. The surface roughness Ra of the pressure-sensitive adhesive surface after heating the pressure-sensitive adhesive sheet of the present invention is preferably 3 μm or more, more preferably 5 μm or more. Within such a range, a pressure-sensitive adhesive sheet can be obtained in which the adhesive strength decreases or disappears after heating and the adherend can be easily peeled off. The surface roughness Ra of the pressure-sensitive adhesive surface refers to the surface roughness Ra of the pressure-sensitive adhesive surface of the pressure-sensitive adhesive sheet after heating without an adherend. The surface roughness Ra can be measured according to JIS B 0601: 1994.

FIG. 2 is a schematic cross-sectional view of an adhesive sheet according to another preferred embodiment of the present invention. The pressure-sensitive adhesive sheet 200 further includes a base material 30 on the side opposite to the pressure-sensitive adhesive surface 11. Although not shown, any appropriate pressure-sensitive adhesive layer or adhesive layer may be provided on the opposite side of the base material 30 from the covering material region 20. Moreover, the release sheet may be arrange | positioned on the outer side of the base material 30 until the adhesive sheet of this invention is put to practical use. When disposing release paper on the outside of the substrate 30, the release paper can be attached to the substrate via any suitable adhesive. In FIG. 2, the adhesive region 10 and the covering material region 20 are formed on one side of the base material 30, but the adhesive region 10 and the covering material region 20 are formed on both sides of the base material 30. For example, a configuration of adhesive region / coating material region / base material / coating material region / adhesive region may be employed.

B. Covering material region The pressure-sensitive adhesive sheet of the present invention has an elastic modulus at 25 ° C. on the surface opposite to the pressure-sensitive adhesive surface of 1 MPa or more, preferably 1 MPa to 5000 MPa, more preferably as described above. Is from 1 MPa to 3500 MPa, more preferably from 1 MPa to 1000 MPa, and particularly preferably from 10 MPa to 600 MPa. The pressure-sensitive adhesive sheet having a surface exhibiting such an elastic modulus can be obtained, for example, by forming a covering material region formed of a material different from the pressure-sensitive adhesive region. The elastic modulus of the coating material region by the nanoindentation method may correspond to the elastic modulus of the surface opposite to the adhesive surface by the nanoindentation method. The modulus of elasticity by the nanoindentation method is obtained by continuously measuring the load and depth of indentation when the indenter is pushed into the sample (for example, adhesive surface) during loading and unloading. The elastic modulus obtained from the applied load-indentation depth curve. In this specification, the elastic modulus by the nanoindentation method means an elastic modulus measured as described above under the measurement conditions of load: 1 mN, load / unloading speed: 0.1 mN / s, and holding time: 1 s.

In the present invention, an electronic component or the like can be obtained by forming a surface having an elastic modulus of 1 MPa or more by the nanoindentation method on the side opposite to the adhesive surface, that is, by forming a covering material region exhibiting the elastic modulus. It is possible to provide an adhesive sheet that can contribute to the realization of excellent cutting accuracy as a temporary fixing sheet for cutting. Further, by setting the elastic modulus of the coating material region by the nanoindentation method to 5000 MPa or less, the coating material region can follow the unevenness of the thermally expandable microsphere protruding from the adhesive region, and the thermally expandable micro The thermally expandable microsphere can be coated in a form in which a sphere is embedded. In addition, it is possible to provide a pressure-sensitive adhesive sheet that can contribute to the realization of excellent cutting accuracy without impairing the flexibility required for the whole pressure-sensitive adhesive sheet (for example, flexibility enough to follow the adherend).

The tensile elastic modulus at 25 ° C. of the coating material region is preferably 1 MPa or more, more preferably 1 MPa to 5000 MPa, and further preferably 1 MPa to 1000 MPa. If it is such a range, the effect similar to the effect demonstrated above about the elasticity modulus by a nanoindentation method can be acquired. The tensile elastic modulus can be measured according to JIS K 7161: 2008.

The bending elastic modulus at 25 ° C. of the coating material region is preferably 1 MPa or more, more preferably 1 MPa to 5000 MPa, and further preferably 1 MPa to 1000 MPa. If it is such a range, the effect similar to the effect demonstrated above about the elasticity modulus by a nanoindentation method can be acquired. The flexural modulus can be measured according to JIS K 7171: 2008.

The thickness of the covering material region can be set to any appropriate value according to the unevenness (size) of the thermally expandable microsphere protruding from the adhesive region. The thickness of the coating material region is preferably a thickness that can cover all the thermally expandable microspheres protruding from the pressure-sensitive adhesive region, for example, 0.1 μm to 200 μm, and preferably 0.1 μm to 100 μm. More preferably, the thickness is 0.1 μm to 45 μm. In the present specification, the thickness of the covering material region is defined as the covering material from the interface 1 between the covering material constituting the covering material region 20 and the adhesive 12 constituting the adhesive region 10, as shown in FIG. This refers to the distance to the surface 21 on the opposite side of the region from the interface 1. That is, the portion where the heat-expandable microsphere 13 protrudes from the adhesive region 10 is excluded from the evaluation target of the thickness of the coating material region. When the interface 1 is clear when the adhesive sheet is cut and the cut section is visually observed, the thickness of the covering material region can be measured using a ruler, a caliper, and a micrometer. Moreover, you may measure the thickness of a coating | covering material area | region using microscopes, such as an electron microscope, an optical microscope, and an atomic force microscope. Further, the thickness of the covering material region may be measured by discriminating the interface based on the difference in composition between the covering material region and the adhesive region. For example, Raman spectroscopic analysis, infrared spectroscopic analysis, X-ray electron spectroscopic analysis, etc .; matrix-assisted laser desorption ionization time-of-flight mass spectrometer (MALDI-TOFMS) and time-of-flight secondary ion mass spectrometer (TOF-SIMS) ), Etc., to analyze the composition of the coating material constituting the coating material region and the pressure sensitive adhesive constituting the pressure sensitive adhesive region, and to determine the interface according to the difference in the composition to measure the thickness of the coating material region. Can do. Thus, the method of discriminating the interface by spectroscopic analysis or mass spectrometry is useful when it is difficult to discriminate the interface visually or by observation with a microscope.

Examples of the material constituting the coating material region include a silicone polymer, an epoxy polymer, a polycarbonate polymer, a vinyl polymer, an acrylic polymer, a urethane polymer, a polyester polymer (for example, polyethylene terephthalate), and a polyolefin polymer. , Polymer materials such as polyamide-based polymers, polyimide-based polymers, and unsaturated hydrocarbon-based polymers. By using these polymer materials, it is possible to easily form a coating material region having the above elastic modulus by appropriately selecting a monomer type, a crosslinking agent, a polymerization degree, and the like. Moreover, the polymer material is excellent in affinity with the thermally expandable microsphere, the pressure-sensitive adhesive constituting the pressure-sensitive adhesive region, and the base material. You may use said polymer material individually or in combination of 2 or more types.

As the material constituting the covering material region, a resin material that can be cured (increased elastic modulus) by irradiation with active energy rays may be used. If the covering material region is formed of such a material, the elastic modulus in the above range can be obtained by irradiating active energy rays after application, with low elasticity, high flexibility and excellent handleability when the adhesive sheet is applied. A pressure-sensitive adhesive sheet that can be adjusted to be obtained can be obtained. Examples of the active energy rays include gamma rays, ultraviolet rays, visible rays, infrared rays (heat rays), radio waves, alpha rays, beta rays, electron beams, plasma flows, ionizing rays, particle rays and the like. In the covering material region composed of a resin material that can be cured by irradiation with active energy rays, the elastic modulus according to the nanoindentation method after irradiation with active energy rays falls within the above range. Moreover, it is preferable that the said tensile elastic modulus and / or bending elastic modulus after irradiation of an active energy ray become the said range for the coating | covering material area | region comprised from the resin material which can be hardened | cured by irradiation of an active energy ray.

Examples of resin materials that can be cured (increased elastic modulus) by irradiation with active energy rays include, for example, an ultraviolet curing system (written by Kiyomi Kato, published by General Technology Center, (1989)), photocuring technology (Technical Information Association ( 2000)), JP-A-2003-292916, JP-A-4151850 and the like. More specifically, a resin material (R1) containing a polymer as a base material and an active energy ray reactive compound (monomer or oligomer), a resin material (R2) containing an active energy ray reactive polymer, and the like can be mentioned.

Examples of the base polymer include natural rubber, polyisobutylene rubber, styrene / butadiene rubber, styrene / isoprene / styrene block copolymer rubber, recycled rubber, butyl rubber, polyisobutylene rubber, and nitrile rubber (NBR). Examples thereof include rubber polymers; silicone polymers; acrylic polymers. These polymers may be used alone or in combination of two or more.

Examples of the active energy ray reactive compound include photoreactive monomers or oligomers having a functional group having a carbon-carbon multiple bond such as acryloyl group, methacryloyl group, vinyl group, allyl group, and acetylene group. Specific examples of the photoreactive monomer or oligomer include trimethylolpropane tri (meth) acrylate, tetramethylolmethanetetra (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipenta Erythritol monohydroxypenta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, polyethylene glycol di (meth) acrylate, etc. (Meth) acryloyl group-containing compounds; dimer to pentamer of the (meth) acryloyl group-containing compounds;

Further, as the active energy ray-reactive compound, monomers such as epoxidized butadiene, glycidyl methacrylate, acrylamide, and vinyl siloxane; or oligomers composed of the monomers may be used. The resin material (R1) containing these compounds can be cured by high energy rays such as ultraviolet rays and electron beams.

Furthermore, as the active energy ray reactive compound, a mixture of an organic salt such as an onium salt and a compound having a plurality of heterocyclic rings in the molecule may be used. In the mixture, an organic salt is cleaved by irradiation with active energy rays (for example, ultraviolet rays and electron beams) to generate ions, which act as starting species to cause a ring opening reaction of the heterocyclic ring to form a three-dimensional network structure. Can do. Examples of the organic salts include iodonium salts, phosphonium salts, antimonium salts, sulfonium salts, and borate salts. Examples of the heterocyclic ring in the compound having a plurality of heterocyclic rings in the molecule include oxirane, oxetane, oxolane, thiirane, aziridine and the like.

In the resin material (R1) containing the polymer as the base material and the active energy ray-reactive compound, the content ratio of the active energy ray-reactive compound is preferably 0.00 with respect to 100 parts by weight of the polymer as the base material. 1 to 500 parts by weight, more preferably 1 to 300 parts by weight, still more preferably 10 to 200 parts by weight.

The resin material (R1) containing the polymer as the base material and the active energy ray-reactive compound can contain any appropriate additive as necessary. Examples of the additive include an active energy ray polymerization initiator, an active energy ray polymerization accelerator, a crosslinking agent, a plasticizer, and a vulcanizing agent. Any appropriate initiator may be used as the active energy ray polymerization initiator depending on the type of active energy ray used. The active energy ray polymerization initiators may be used alone or in combination of two or more. In the resin material (R1) containing the polymer as the base material and the active energy ray-reactive compound, the content ratio of the active energy ray polymerization initiator is preferably 0.1 with respect to 100 parts by weight of the polymer as the base material. Parts by weight to 10 parts by weight, more preferably 1 part by weight to 5 parts by weight.

Examples of the active energy ray-reactive polymer include polymers having a functional group having a carbon-carbon multiple bond such as an acryloyl group, a methacryloyl group, a vinyl group, an allyl group, and an acetylene group. Specific examples of the polymer having an active energy ray-reactive functional group include a polymer composed of a polyfunctional (meth) acrylate; a photocationic polymerization type polymer; a cinnamoyl group-containing polymer such as polyvinyl cinnamate; a diazotized amino novolak Resin; polyacrylamide; and the like. Further, as the resin material (R2) containing an active energy ray-reactive polymer, a mixture of an active energy ray-reactive polymer having an allyl group and a compound having a thiol group can also be used. In addition, as long as the coating material area | region precursor which has practical hardness (viscosity) can be formed before hardening by active energy ray irradiation (for example, when sticking an adhesive sheet), active energy ray reactive functional group An oligomer having an active energy ray-reactive functional group can also be used in addition to a polymer having a.

The resin material (R2) containing the active energy ray-reactive polymer may further contain the active energy ray-reactive compound (monomer or oligomer). Moreover, the resin material (R2) containing the said active energy ray reactive polymer may contain arbitrary appropriate additives as needed. The specific example of an additive is the same as that of the additive which can be contained in the resin material (R1) containing the polymer used as a base material, and an active energy ray reactive compound. In the resin material (R2) containing the active energy ray reactive polymer, the content ratio of the active energy ray polymerization initiator is preferably 0.1 to 10 parts by weight with respect to 100 parts by weight of the active energy ray reactive polymer. More preferably, it is 1 to 5 parts by weight.

The dressing region may further include beads. Examples of the beads include glass beads and resin beads. If such beads are added to the covering material region, the elastic modulus of the covering material region can be improved, and an adhesive sheet capable of processing the workpiece with higher accuracy can be obtained. The average particle diameter of the beads is, for example, 0.01 μm to 50 μm. The amount of beads added is, for example, 10 to 200 parts by weight, preferably 20 to 100 parts by weight, with respect to 100 parts by weight of the entire covering material region.

C. Adhesive area | region The said adhesive area | region preferably contains an adhesive and a thermally expansible microsphere.

The thickness of the pressure-sensitive adhesive region is preferably 50 μm or less, more preferably 1 μm to 50 μm, still more preferably 1 μm to 25 μm, and particularly preferably 1 μm to 15 μm. When the adhesive area is thicker than 50 μm, when used as a temporary fixing sheet when cutting electronic parts, etc., the chip after reattaching, the cut surface becomes unstable, the chip is missing at the time of cutting There is a risk of problems such as occurrence of cuttings and generation of cutting waste. In the present invention, by forming the covering material region in which the elastic modulus is appropriately adjusted, it is possible to allow the heat-expandable microspheres to protrude from the pressure-sensitive adhesive region, and to thin the pressure-sensitive adhesive region. it can. On the other hand, when the thickness of the pressure-sensitive adhesive region is less than 1 μm, there is a possibility that sufficient adhesive force cannot be obtained. In the present specification, the thickness of the pressure-sensitive adhesive region refers to the pressure-sensitive adhesive surface 11 from the interface 1 between the coating material constituting the coating material region 20 and the pressure-sensitive adhesive constituting the pressure-sensitive adhesive region 10 as shown in FIG. The distance to. That is, the portion where the heat-expandable microsphere 13 protrudes from the adhesive region 10 is excluded from the evaluation target of the thickness of the adhesive region. The method for determining the interface 1 is as described in the above section B.

In the pressure-sensitive adhesive sheet of the present invention, the elastic modulus according to the nanoindentation method of the pressure-sensitive adhesive surface at the temperature at which the pressure-sensitive adhesive sheet is stuck is preferably less than 100 MPa, more preferably 0.1 MPa to 50 MPa, The pressure is preferably 0.1 MPa to 10 MPa. The elastic modulus of the adhesive region by the nanoindentation method corresponds to the elastic modulus of the adhesive surface by the nanoindentation method. The elastic modulus of the adhesive surface by the nanoindentation method means the elastic modulus measured by the measurement method described in the above section B by selecting a portion where no thermally expandable microspheres exist, that is, the elastic modulus of the adhesive. The temperature at the time of sticking the pressure-sensitive adhesive sheet is, for example, 10 to 80 ° C. when an acrylic pressure-sensitive adhesive is used as the pressure-sensitive adhesive, and when a styrene-diene block copolymer pressure-sensitive adhesive is used as the pressure-sensitive adhesive. 40 ° C to 120 ° C.

(Adhesive)
The pressure-sensitive adhesive is preferably one that does not restrain expansion or foaming of the thermally expandable microspheres during heating. Examples of the adhesive include acrylic adhesives, rubber adhesives, vinyl alkyl ether adhesives, silicone adhesives, polyester adhesives, polyamide adhesives, urethane adhesives, and styrene-diene block co-polymers. Polymer-based pressure-sensitive adhesives, radiation-curable adhesives, and creep characteristics-improving pressure-sensitive adhesives in which a hot-melt resin having a melting point of about 200 ° C. or less is blended with these pressure-sensitive adhesives (for example, JP-A-56-61468) Gazette, JP-A 63-17981, etc.). Among these, an acrylic pressure-sensitive adhesive or a rubber-based pressure-sensitive adhesive is preferable. In addition, you may use the said adhesive individually or in combination of 2 or more types.

Examples of the acrylic pressure-sensitive adhesive include, for example, an acrylic pressure-sensitive adhesive based on an acrylic polymer (homopolymer or copolymer) using one or more (meth) acrylic acid alkyl esters as monomer components. Etc. Specific examples of alkyl (meth) acrylates include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, (meth ) Isobutyl acrylate, s-butyl (meth) acrylate, t-butyl (meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate , 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, nonyl (meth) acrylate, isononyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, (meth) acrylic acid Undecyl, dodecyl (meth) acrylate, tridecyl (meth) acrylate, (me ) Tetradecyl acrylate, pentadecyl (meth) acrylate, hexadecyl (meth) acrylate, heptadecyl (meth) acrylate, octadecyl (meth) acrylate, nonadecyl (meth) acrylate, eicosyl (meth) acrylate (meta) ) C1-20 alkyl ester of acrylic acid. Among them, (meth) acrylic acid alkyl esters having a linear or branched alkyl group having 4 to 18 carbon atoms can be preferably used.

The acrylic polymer is a unit corresponding to another monomer component copolymerizable with the (meth) acrylic acid alkyl ester, if necessary, for the purpose of modifying cohesion, heat resistance, crosslinkability and the like. 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) acrylamide Sulfonic acid group-containing monomers such as 2-methylpropanesulfonic acid, (meth) acrylamidepropanesulfonic acid, sulfopropyl (meth) acrylate, (meth) acryloyloxynaphthalenesulfonic acid; (meth) acrylamide, N, N-dimethyl (meta ) Acrylamide, N-butyl (meth) acrylamide, N-methylol (meth) acrylamide, (N-substituted) amide monomers such as N-methylolpropane (meth) acrylamide; aminoethyl (meth) acrylate, (meth) acrylic (Meth) acrylic acid aminoalkyl monomers such as N, N-dimethylaminoethyl acid and t-butylaminoethyl (meth) acrylate; (meth) acrylic acid (meth) acrylate, ) Alkoxy acrylate Rutile monomers; maleimide monomers such as N-cyclohexylmaleimide, N-isopropylmaleimide, N-laurylmaleimide, N-phenylmaleimide; N-methylitaconimide, N-ethylitaconimide, N-butylitaconimide, N-octyl Itaconimide monomers such as itaconimide, N-2-ethylhexylitaconimide, N-cyclohexylitaconimide, N-laurylitaconimide; N- (meth) acryloyloxymethylenesuccinimide, N- (meth) acryloyl-6-oxyhexamethylene Succinimide monomers such as succinimide and N- (meth) acryloyl-8-oxyoctamethylene succinimide; vinyl acetate, vinyl propionate, N-vinyl pyrrolidone, methyl vinyl pyro Vinyl such as lidone, vinylpyridine, vinylpiperidone, vinylpyrimidine, vinylpiperazine, vinylpyrazine, vinylpyrrole, vinylimidazole, vinyloxazole, vinylmorpholine, N-vinylcarboxylic amides, styrene, α-methylstyrene, N-vinylcaprolactam 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, (meth) acrylic acid Glycol acrylic ester monomers such as methoxyethylene glycol and (meth) acrylic acid methoxypolypropylene glycol; (meth) acrylic acid tetrahydrofur Acrylic acid ester monomers having heterocycles such as ril, 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, dipentaerythritol hexa Polyfunctional monomers such as (meth) acrylates, epoxy acrylates, polyester acrylates, urethane acrylates; olefinic monomers such as isoprene, butadiene, isobutylene; And vinyl ether monomers such as vinyl ether. These monomer components may be used alone or in combination of two or more.

Examples of the rubber-based adhesive include natural rubber; polyisoprene rubber, styrene / butadiene (SB) rubber, styrene / isoprene (SI) rubber, styrene / isoprene / styrene block copolymer (SIS) rubber, and styrene / butadiene.・ Styrene block copolymer (SBS) rubber, styrene / ethylene / butylene / styrene block copolymer (SEBS) rubber, styrene / ethylene / propylene / styrene block copolymer (SEPS) rubber, styrene / ethylene / propylene block copolymer Examples thereof include rubber-based pressure-sensitive adhesives based on polymer (SEP) rubber, recycled rubber, butyl rubber, polyisobutylene, synthetic rubbers such as modified products thereof, and the like.

The pressure-sensitive adhesive may contain any appropriate additive as necessary. Examples of the additive include a crosslinking agent, a tackifier, a plasticizer (for example, trimellitic acid ester plasticizer, pyromellitic acid ester plasticizer), pigment, dye, filler, anti-aging agent, conductive material. , Antistatic agents, ultraviolet absorbers, light stabilizers, release modifiers, softeners, surfactants, flame retardants, antioxidants and the like.

Any appropriate tackifier may be used as the tackifier. As the tackifier, for example, a tackifier resin is used. Specific examples of tackifying resins include rosin tackifying resins (eg, unmodified rosin, modified rosin, rosin phenolic resin, rosin ester resin, etc.), terpene tackifying resins (eg, terpene resins, terpene phenols). Resin, styrene modified terpene resin, aromatic modified terpene resin, hydrogenated terpene resin), hydrocarbon tackifier resin (for example, aliphatic hydrocarbon resin, aliphatic cyclic hydrocarbon resin, aromatic resin) Hydrocarbon resins (eg, styrene resins, xylene resins, etc.), aliphatic / aromatic petroleum resins, aliphatic / alicyclic petroleum resins, hydrogenated hydrocarbon resins, coumarone resins, coumarone indene resins Etc.), phenolic tackifying resins (eg, alkylphenolic resins, xyleneformaldehyde resins, resoles, novos) Tsu, etc. h), ketone-based tackifying resins, polyamide-based tackifying resins, epoxy-based tackifying resins, such as an elastomer-based tackifying resins. Among these, rosin-based tackifier resins, terpene-based tackifier resins, or hydrocarbon-based tackifier resins (such as styrene resins) are preferable. You may use a tackifier individually or in combination of 2 or more types.

Commercially available products may be used as the tackifier. Specific examples of commercially available tackifiers include terpene phenol resins such as “YS Polystar S145” and “Mighty Ace K140” manufactured by Yasuhara Chemical Co., Ltd. and “Tamanor 901” manufactured by Arakawa Chemical Co., Ltd .; Sumitomo Bakelite Rosin phenolic resin such as “Sumilite Resin PR-12603” manufactured by Arakawa Chemical Co., Ltd .; Alkylphenol resin such as “Tamanol 1010R” and “Tamanol 200N” manufactured by Arakawa Chemical Co., Ltd. An alicyclic saturated hydrocarbon resin such as “Arcon P-140” manufactured by Arakawa Chemical Co., Ltd.

The addition amount of the tackifier is preferably 5 to 100 parts by weight, more preferably 10 to 50 parts by weight with respect to 100 parts by weight of the base polymer.

Examples of the crosslinking agent include an isocyanate crosslinking agent, an epoxy crosslinking agent, a melamine crosslinking agent, a peroxide crosslinking agent, a urea crosslinking agent, a metal alkoxide crosslinking agent, a metal chelate crosslinking agent, and a metal. Examples thereof include salt-based crosslinking agents, carbodiimide-based crosslinking agents, oxazoline-based crosslinking agents, aziridine-based crosslinking agents, and amine-based crosslinking agents. Of these, an isocyanate-based crosslinking agent or an epoxy-based crosslinking agent is preferable.

Specific examples of the isocyanate-based crosslinking agent include lower aliphatic polyisocyanates such as butylene diisocyanate and hexamethylene diisocyanate; alicyclic isocyanates such as cyclopentylene diisocyanate, cyclohexylene diisocyanate and isophorone diisocyanate; 2,4- Aromatic isocyanates such as tolylene diisocyanate, 4,4′-diphenylmethane diisocyanate, xylylene diisocyanate; trimethylolpropane / tolylene diisocyanate trimer adduct (trade name “Coronate L” manufactured by Nippon Polyurethane Industry Co., Ltd.) Methylolpropane / hexamethylene diisocyanate trimer adduct (trade name “Coronate HL” manufactured by Nippon Polyurethane Industry Co., Ltd.), isoform of hexamethylene diisocyanate Cyanurate body (Nippon Polyurethane Industry Co., Ltd. under the trade name "Coronate HX") isocyanate adducts of the like; and the like. The content of the isocyanate-based crosslinking agent can be set to any appropriate amount depending on the desired adhesive strength, and is typically 0.1 to 20 parts by weight with respect to 100 parts by weight of the base polymer. More preferably, it is 0.5 to 10 parts by weight.

Examples of the epoxy crosslinking agent include N, N, N ′, N′-tetraglycidyl-m-xylenediamine, diglycidylaniline, 1,3-bis (N, N-glycidylaminomethyl) cyclohexane (Mitsubishi Gas). Chemical name, “Tetrad C”), 1,6-hexanediol diglycidyl ether (manufactured by Kyoeisha Chemical Co., trade name “Epolite 1600”), neopentyl glycol diglycidyl ether (manufactured by Kyoeisha Chemical Co., Ltd., trade name “ Epolite 1500NP "), ethylene glycol diglycidyl ether (manufactured by Kyoeisha Chemical Co., trade name" Epolite 40E "), propylene glycol diglycidyl ether (manufactured by Kyoeisha Chemical Co., trade name" Epolite 70P "), polyethylene glycol diglycidyl ether (Japan) Product name "Epior" E-400 "), polypropylene glycol diglycidyl ether (manufactured by NOF Corporation, trade name" Epiol P-200 "), sorbitol polyglycidyl ether (manufactured by Nagase ChemteX Corporation, trade name" Denacol EX-611 "), glycerol poly Glycidyl ether (manufactured by Nagase ChemteX Corporation, trade name “Denacol EX-314”), pentaerythritol polyglycidyl ether, polyglycerol polyglycidyl ether (manufactured by Nagase ChemteX Corporation, trade name “Denacol EX-512”), sorbitan polyglycidyl Ether, trimethylolpropane polyglycidyl ether, adipic acid diglycidyl ester, o-phthalic acid diglycidyl ester, triglycidyl-tris (2-hydroxyethyl) isocyanurate, Le Shinji glycidyl ethers, bisphenol -S- diglycidyl ether, epoxy resins having two or more epoxy groups in the molecule. The content of the epoxy-based crosslinking agent can be set to any appropriate amount depending on the desired adhesive strength, and is typically 0.01 to 10 parts by weight with respect to 100 parts by weight of the base polymer. More preferably, it is 0.03 to 5 parts by weight.

(Thermally expandable microsphere)
As the thermally expandable microsphere, any appropriate thermally expandable microsphere can be used as long as it is a microsphere that can expand or foam by heating. As the thermally expandable microsphere, for example, a microsphere in which a substance that easily expands by heating is encapsulated in an elastic shell can be used. Such thermally expandable microspheres can be produced by any appropriate method, for example, a coacervation method, an interfacial polymerization method, or the like.

Examples of the material that easily expands when heated include propane, propylene, butene, normal butane, isobutane, isopentane, neopentane, normal pentane, normal hexane, isohexane, heptane, octane, petroleum ether, methane halide, tetraalkylsilane. And low-boiling-point liquids such as azodicarbonamide that is gasified by thermal decomposition.

Examples of the material constituting the shell include nitrile monomers such as acrylonitrile, methacrylonitrile, α-chloroacrylonitrile, α-ethoxyacrylonitrile, fumaronitrile; acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, Carboxylic acid monomers such as citraconic acid; vinylidene chloride; vinyl acetate; methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, (Meth) acrylic esters such as isobornyl (meth) acrylate, cyclohexyl (meth) acrylate, benzyl (meth) acrylate, β-carboxyethyl acrylate; styrene mono, such as styrene, α-methylstyrene, chlorostyrene Chromatography; and the polymer composed like; acrylamides, substituted acrylamides, methacrylamide, amide monomers such as substituted methacrylamide. The polymer composed of these monomers may be a homopolymer or a copolymer. Examples of the copolymer include vinylidene chloride-methyl methacrylate-acrylonitrile copolymer, methyl methacrylate-acrylonitrile-methacrylonitrile copolymer, methyl methacrylate-acrylonitrile copolymer, acrylonitrile-methacrylonitrile-itaconic acid copolymer. A polymer etc. are mentioned.

An inorganic foaming agent or an organic foaming agent may be used as the thermally expandable microsphere. Examples of the inorganic foaming agent include ammonium carbonate, ammonium hydrogen carbonate, sodium hydrogen carbonate, ammonium nitrite, sodium borohydride, various azides and the like. Examples of the organic foaming agent include chlorofluorinated alkane compounds such as trichloromonofluoromethane and dichloromonofluoromethane; azo compounds such as azobisisobutyronitrile, azodicarbonamide, and barium azodicarboxylate. Hydrazine compounds such as para-toluenesulfonyl hydrazide, diphenylsulfone-3,3′-disulfonyl hydrazide, 4,4′-oxybis (benzenesulfonyl hydrazide), allyl bis (sulfonyl hydrazide); p-toluylene sulfonyl semicarbazide, 4, Semicarbazide compounds such as 4′-oxybis (benzenesulfonyl semicarbazide); Triazole compounds such as 5-morpholyl-1,2,3,4-thiatriazole; N, N′-dinitrosopentamethylenetetramine, N, '- dimethyl -N, N'-dinitrosoterephthalamide; etc. N- nitroso compounds, and the like.

Commercially available products may be used as the above-mentioned thermally expandable microspheres. Specific examples of commercially available thermally expandable microspheres include “Matsumoto Microsphere” (grade: F-30, F-30D, F-36D, F-36LV, F-50) manufactured by Matsumoto Yushi Seiyaku Co., Ltd. F-50D, F-65, F-65D, FN-100SS, FN-100SSD, FN-180SS, FN-180SSD, F-190D, F-260D, F-2800D), trade names “Nippon Philite” "Expansel" (grade: 053-40, 031-40, 920-40, 909-80, 930-120), "Die Form" (grade: H750, H850, H1100, S2320D, S2640D, manufactured by Kureha Chemical Industry Co., Ltd.) M330, M430, M520), “ADVANCEL” manufactured by Sekisui Chemical Co., Ltd. (grade: EML101, EMH204, EHM3) 1, EHM302, EHM303, EM304, EHM401, EM403, EM501) and the like.

The particle diameter of the thermally expandable microsphere before heating is preferably 0.5 μm to 80 μm, more preferably 5 μm to 45 μm, still more preferably 10 μm to 20 μm, and particularly preferably 10 μm to 15 μm. . Therefore, the particle size before heating of the thermally expandable microspheres is preferably 6 μm to 45 μm, more preferably 15 μm to 35 μm, in terms of average particle size. The above particle diameter and average particle diameter are values obtained by the particle size distribution measurement method in the laser scattering method.

It is preferable that the thermally expandable microspheres have an appropriate strength that does not rupture until the volume expansion coefficient is preferably 5 times or more, more preferably 7 times or more, and even more preferably 10 times or more. When such a heat-expandable microsphere is used, the adhesive force can be efficiently reduced by heat treatment.

The content ratio of the heat-expandable microspheres in the pressure-sensitive adhesive region can be appropriately set according to the desired decrease in adhesive strength. The content ratio of the heat-expandable microspheres is, for example, 1 part by weight to 150 parts by weight, preferably 10 parts by weight to 130 parts by weight, and more preferably 25 parts by weight with respect to 100 parts by weight of the base polymer forming the pressure-sensitive adhesive region. ~ 100 parts by weight.

D. Base material Examples of the base material include resin sheets, nonwoven fabrics, paper, metal foils, woven fabrics, rubber sheets, foamed sheets, and laminates thereof (particularly, laminates including resin sheets). Examples of the resin constituting the resin sheet include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate (PBT), polyethylene (PE), polypropylene (PP), ethylene-propylene copolymer, ethylene- Vinyl acetate copolymer (EVA), polyamide (nylon), wholly aromatic polyamide (aramid), polyimide (PI), polyvinyl chloride (PVC), polyphenylene sulfide (PPS), fluororesin, polyether ether ketone (PEEK) ) And the like. Examples of the nonwoven fabric include nonwoven fabrics made of natural fibers having heat resistance such as nonwoven fabrics including manila hemp; synthetic resin nonwoven fabrics such as polypropylene resin nonwoven fabrics, polyethylene resin nonwoven fabrics and ester resin nonwoven fabrics.

The thickness of the base material can be set to any appropriate thickness depending on the desired strength or flexibility, the purpose of use, and the like. The thickness of the substrate is preferably 1000 μm or less, more preferably 1 μm to 1000 μm, still more preferably 1 μm to 500 μm, particularly preferably 3 μm to 300 μm, and most preferably 5 μm to 250 μm.

The surface of the substrate may be subjected to surface treatment. Examples of the surface treatment include corona treatment, chromic acid treatment, ozone exposure, flame exposure, high piezoelectric impact exposure, ionizing radiation treatment, and coating treatment with a primer. By performing such a surface treatment, the adhesion between the covering material region and the substrate can be enhanced. In particular, a coating treatment with an organic coating material is preferable because it improves adhesion and the coating material region is less likely to be thrown and destroyed during heat peeling.

Examples of the organic coating material include materials described in Plastic Hard Coat Material II (CMC Publishing, (2004)). Preferably, a urethane-based polymer, more preferably polyacryl urethane, polyester urethane, or a precursor thereof is used. This is because coating and application to the base material are simple, and various industrial products can be selected and obtained at low cost. The urethane polymer is, for example, a polymer 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). The organic coating material may contain a chain extender such as polyamine, an anti-aging agent, an oxidation stabilizer and the like as optional additives. The thickness of the organic coating layer is not particularly limited, but for example, about 0.1 μm to 10 μm is suitable, preferably about 0.1 μm to 5 μm, and more preferably about 0.5 μm to 5 μm.

E. Production method of pressure-sensitive adhesive sheet As a method for producing the pressure-sensitive adhesive sheet of the present invention, for example, (1) a pressure-sensitive adhesive coating layer is formed by applying the pressure-sensitive adhesive on a release film (release paper); A method of forming an adhesive region by embedding the thermally expandable microspheres in a coating layer by pressing or the like, and forming (laminating) a coating material region on the adhesive region, (2) on the release film, A method of forming a pressure-sensitive adhesive coating layer by applying a pressure-sensitive adhesive region-forming composition containing a pressure-sensitive adhesive and thermally expandable microspheres, and forming (laminating) a coating material region on the pressure-sensitive adhesive coating layer; ) After applying the above-mentioned pressure-sensitive adhesive on the release film to form a pressure-sensitive adhesive coating layer, a coating material region is formed (laminated) on the pressure-sensitive adhesive coating layer, and then the release film is peeled off to adhere The thermally expandable microspheres are pre-coated from the surface (adhesive surface) side opposite to the coating material region of the agent coating layer (4) A method of forming a coating material region on a release film, installing thermally expandable microspheres on one surface thereof, and further applying an adhesive on the installation surface. . In the above methods (1) to (4), the pressure-sensitive adhesive layer can be formed by drying the pressure-sensitive adhesive coating layer formed by applying the pressure-sensitive adhesive. The drying is performed at any appropriate timing. Can be broken. The drying may be performed before or after embedding the thermally expandable microspheres. Further, it may be before or after the coating material region is formed. When drying after embedding the thermally expandable microspheres, it is preferable to dry at a temperature at which the thermally expandable microspheres are difficult to expand or foam. After the operations shown in (1) and (2) above, the release film may be peeled off, and the adhesive surface is protected leaving the release film until the adhesive sheet is put to practical use. Also good.

When the pressure-sensitive adhesive sheet of the present invention comprises a substrate, the pressure-sensitive adhesive sheet is a surface opposite to the pressure-sensitive adhesive region in the covering material region after the operations (1) to (4) (the side opposite to the pressure-sensitive adhesive surface). Can be obtained by adhering the base material to any surface via any appropriate adhesive or pressure-sensitive adhesive. Moreover, the laminated body of a base material and a coating | covering material area | region and the laminated body of a release film and an adhesive area | region (or adhesive coating layer) may be produced separately, and these laminated bodies may be bonded together.

As a method of forming the covering material region, (i) the polymer material or resin material described in the above section B is thermally melted to obtain a molded body in a film shape by extrusion molding, and the molded body is formed into the pressure-sensitive adhesive region ( Or a method of laminating on a pressure-sensitive adhesive coating layer) or a substrate, (ii) applying a resin solution containing the polymer material or resin material to the pressure-sensitive adhesive region (or pressure-sensitive adhesive coating layer) or substrate, and then drying. (Iii) A coating material region forming composition containing a monomer, oligomer, or macromer capable of forming the polymer material or resin material is applied to the pressure-sensitive adhesive region (or pressure-sensitive adhesive coating layer) or substrate and coated. Examples thereof include a method of polymerizing the material region forming composition (for example, polymerization by heating, active energy ray irradiation, or the like). According to the method (iii), the amount of solvent and / or heat energy used can be reduced. In the method (ii), the resin solution is applied onto another release film and then dried to obtain a film-like molded article, and then the molded article is applied to the pressure-sensitive adhesive region (or pressure-sensitive adhesive applied). Layer) or a substrate. In the method (iii), the composition for forming a coating material region is applied onto another release film, and then dried to form a coating material region precursor. Alternatively, it may be laminated on a pressure-sensitive adhesive coating layer) or a substrate and then polymerized.

For example, in the above method (iii), when forming a coating material region composed of an epoxy polymer, 2,2- (4-hydroxyphenyl) propanediglycidyl ether, bis (4-hydroxyphenyl) methane, etc. A method of applying a composition for forming a coating material region containing an epoxy compound and any appropriate curing agent and then heating (for example, 60 ° C. to 120 ° C.) may be employed.

For example, in the method (iii), when forming a coating material region composed of a urethane polymer, an isocyanate compound such as lylene diisocyanate and hexamethylene diisocyanate and a polyol compound such as polyether polyol and polyester polyol are included. A method of heating (for example, 60 ° C. to 120 ° C.) after applying the composition for forming a covering material region may be employed.

For example, in the method of (iii) above, when forming a coating material region composed of a vinyl polymer, a composition for forming a coating material region comprising a vinyl compound such as vinyl chloride or styrene and any appropriate initiator Can be used.

The composition for forming a coating material region may contain additives such as an initiator, a catalyst, an ultraviolet absorber, and an antioxidant as necessary. Moreover, the said bead may be included.

When the covering material region is composed of a resin material that can be cured by irradiation with active energy rays, the active energy rays can be irradiated at any appropriate timing to obtain an adhesive sheet. The irradiation with the active energy ray is performed, for example, after attaching an adherend (workpiece). The irradiation with the active energy ray may be performed stepwise. For example, it may be semi-cured before adhering the adherend and may be fully cured after adhering. The type and amount of the active energy ray can be set to any appropriate type and amount depending on the type of resin material constituting the covering material region.

According to the above manufacturing method, the surface of the pressure-sensitive adhesive region on the release film side (the side opposite to the coating material region) becomes the pressure-sensitive adhesive surface. Since the adhesive surface is formed in contact with the release film, there is no protrusion of the heat-expandable microsphere and it is flat. On the other hand, thermally expandable microspheres protrude on the surface of the adhesive region opposite to the adhesive surface. In the present invention, since the protruding heat-expandable microspheres are covered by the covering material region, both surfaces of the pressure-sensitive adhesive sheet are flattened, and therefore the thickness of the pressure-sensitive adhesive region can be reduced. Such a pressure-sensitive adhesive sheet of the present invention can contribute to excellent cutting accuracy and reduction of cutting waste as a temporary fixing sheet when cutting an electronic component or the like.

F. How to use adhesive sheet (manufacturing method of electronic parts)
According to another aspect of the present invention, a method for manufacturing an electronic component is provided. The manufacturing method of the electronic component of this invention includes sticking the electronic component material (board | substrate) obtained by the large area on the said adhesive sheet, and cut | disconnecting this electronic component material.

Examples of the electronic parts include parts for semiconductor devices such as silicon wafers; multilayer capacitors: transparent electrodes;

In the above manufacturing method, first, the pressure-sensitive adhesive sheet is placed on a processing table, and an electronic component material obtained in a large area is stuck on the pressure-sensitive adhesive sheet.

Thereafter, the electronic component material can be cut by any appropriate method to obtain an electronic component. Examples of the cutting method include a method using a blade such as a rotary blade and a flat blade, a method using a laser beam, and the like. When the electronic component material is cut by pressing with a flat blade, the generation of cutting waste is suppressed and the yield is improved. In the present invention, since the adhesive region can be made thin, even if the electronic component material is cut by pressing with a flat blade, the chip after cutting is reattached, the cut surface becomes slanted, or S It is possible to prevent the character from becoming unstable when it becomes a character, or chipping from occurring during cutting. Further, in the present invention, even when a thin blade is used for cutting, the above-described effects can be obtained, and manufacturing loss caused by the thickness of the blade (loss due to a gap generated between chips after cutting) can be reduced. it can. In the manufacture of a more miniaturized electronic component, since the number of cut surfaces is large, the present invention that can reduce the manufacturing loss as described above is particularly useful.

In the above cutting process, cutting may be performed under heating. For example, the processing table may be heated to 30 ° C. to 150 ° C. for cutting.

Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited to these examples. The evaluation methods in the examples are as follows. In Examples, unless otherwise specified, “parts” and “%” are based on weight.

(1) Measurement of thickness of pressure-sensitive adhesive region and coating material region by Raman mapping The pressure-sensitive adhesive sheets obtained in Examples 1 to 3, 5, 6 and 12 to 15 were sectioned with a microtome to prepare measurement samples. The cross section of the measurement sample was subjected to spectroscopic analysis by Raman spectrum using alpha300RSA manufactured by WITec, and a peak derived from a component added only to the coating material region (for example, active energy ray reactive oligomer (UV1700B) in Example 3). The thickness of the coating material region and the pressure-sensitive adhesive region was measured based on the peak intensity of 1640 cm ⁻¹ . Using Example 3 as a representative example, Raman mapping in the measurement is shown in FIG. The surface where the abundance of the component added only in the coating material region is clearly different is the interface 1, the distance from the adhesive surface 11 to the interface 1 is the thickness of the adhesive region, and the surface on the opposite side of the adhesive surface from the interface 1 The distance up to 21 was defined as the thickness of the covering material region.
The measurement conditions for Raman mapping measurement are as follows.
Excitation wavelength: 532 nm
Measurement wave number range: 300 to 3600 cm ^-1
・ Grating: 600 gr / mm
Objective lens: x100
・ Measurement time: 0.2 sec / 1 spectrum ・ Measurement range: 20 × 40 μm
-Number of measurements: 100 x 200 points-Detector: EMCCD

(2) Measurement of thickness of adhesive region and coating material region with SEM The adhesive sheets obtained in Examples 4, 7 to 11, 16, 17 and Comparative Example 1 were cut in the thickness direction with a trimming cutter, and Pt- After performing the Pd sputtering treatment, the cut surface is observed using an S3400N low-vacuum scanning electron microscope (SEM) manufactured by Hitachi High-Technologies Corporation to determine the interface 1 and the distance from the adhesive surface 11 to the interface 1 is determined as an adhesive. The thickness of the region, the surface 21 opposite to the adhesive surface from the interface 1 was taken as the thickness of the covering material region. FIG. 4 shows an SEM image of a cross section of the pressure-sensitive adhesive sheet with Example 11 as a representative example.
The measurement conditions for SEM observation are as follows.
-Observation image: ESED image-Acceleration voltage: 10 kV
・ Magnification: 600 times

(3) Measurement of elastic modulus The pressure-sensitive adhesive sheets obtained in Examples and Comparative Examples were cut in the thickness direction with a microtome, and the elastic modulus of the cut surface was measured with a nanoindenter.
More specifically, with respect to the covering material region, the surface of the covering material region that is substantially perpendicular to the cut surface (the surface opposite to the adhesive surface) and the cut surface that is about 3 μm away from the surface were measured. . An elastic modulus was obtained by numerically processing a displacement-load hysteresis curve obtained by pressing a probe (indenter) against an object to be measured using software (triboscan) attached to the measuring device. In Table 1, the elastic modulus measured on the surface of the cut surface separated by about 3 μm from the surface is shown (average value of three measurements).
The nanoindenter apparatus and measurement conditions are as follows.
Apparatus and measurement conditions / apparatus: Nanoindenter; Tribodenter manufactured by Hystron Inc.
・ Measurement method: Single indentation method ・ Measurement temperature: 25 ° C
・ Push-in speed: about 1000nm / sec
・ Indentation depth: about 800nm
・ Tip: Diamond, Berkovich type (triangular pyramid type)

(4) Adhesive strength measurement (adhesive strength before heating (before expanding thermally expandable microspheres))
The pressure-sensitive adhesive sheets obtained in Examples and Comparative Examples were cut into a size of 20 mm in width and 140 mm in length, and a polyethylene terephthalate film (trade name “Lumirror S-10” Toray Industries, Inc.) as an adherend on the pressure-sensitive adhesive surface. Manufactured in a thickness of 25 μm and a width of 30 mm) in a state of protruding by 5 mm on the left and right sides in accordance with JIS Z 0237: 2009, a 2 kg roller was reciprocated once to prepare a measurement sample. The measurement sample was set in a tensile tester with a thermostatic bath (trade name “Shimadzu Autograph AG-120kN”, manufactured by Shimadzu Corporation) and left for 30 minutes. Thereafter, the load was measured when the adherend was peeled from the pressure-sensitive adhesive sheet in the length direction under the conditions of peeling angle: 180 °, peeling speed (tensile speed): 300 mm / min, and the maximum load ( The maximum value of the load excluding the peak top at the initial stage of measurement was determined, and the maximum load divided by the tape width was defined as the adhesive strength (N / 20 mm width). The above operation was performed in an atmosphere of temperature: 23 ± 3 ° C. and humidity: 65 ± 5% RH.
(Adhesive strength after heating (after expanding or foaming thermally expandable microspheres))
A measurement sample was prepared in the same manner as described above, and the measurement sample was put into a hot air dryer. After leaving still for 1 minute under the maximum expansion temperature (after-mentioned) of a thermally expansible microsphere in a hot air dryer, the to-be-adhered body was peeled similarly to the above, and the adhesive force was measured. The operation before and after the charging into the hot air dryer was performed in an atmosphere of temperature: 23 ± 3 ° C. and humidity: 65 ± 5% RH.

(5) Surface roughness measurement About the adhesive sheet obtained by the Example and the comparative example, after expanding or foaming a thermally expansible microsphere, surface roughness Ra of the adhesive surface was measured. The expansion or foaming of the heat-expandable microspheres was performed by standing in a hot air dryer for 1 minute at the maximum expansion temperature (described later) of the heat-expandable microspheres. The surface roughness was measured using a laser microscope “OLS4000” manufactured by Olympus.

(6) Evaluation of small piece separability after cutting A laminated ceramic sheet of 40 mm × 50 mm (thickness 500 μm) was bonded to the pressure-sensitive adhesive sheets obtained in Examples and Comparative Examples. The multilayer ceramic sheet on the adhesive sheet was cut into a 1 mm × 0.5 mm piece shape with a cutting device “G-CUT8AA” manufactured by UHT. The laminated ceramic sheet on the pressure-sensitive adhesive sheet was placed along the side of a cylinder having a diameter of 30 mm. A heat treatment is performed at a predetermined temperature (maximum expansion temperature of the thermally expandable microsphere (described later)) in a state where it is installed on the cylinder, and the thermally expandable microsphere is expanded to peel off the small pieces from the adhesive sheet. The number of chips with no separation between the chips was counted. The number obtained by dividing the number of non-separated chips by 100% when completely separated was used as an index of separability. The index is less than 2%, the index is 2% or more and less than 5%, the index is 5% or more and less than 15%, and the index is 15% or more.
Details of the composition of the multilayer ceramic sheet and the cutting conditions of the cutting apparatus are as follows.
(Laminated ceramic sheet)
By adding 100 parts of barium titanate powder, 15 parts of polyvinyl butyral resin, 6 parts of bis (2-ethylhexyl) phthalate, and 2 parts of diglycerin stearate to a toluene solvent, and mixing and dispersing by a ball mill disperser. A dielectric toluene solution was obtained. Apply this solution to the silicone release agent-treated surface of a polyethylene terephthalate film with a silicone release agent-treated surface (manufactured by Mitsubishi Polyester Film Co., Ltd., trade name “MRF38”, thickness: 38 μm) so that the thickness after evaporation of the solvent is 50 μm. It was applied and dried to obtain a ceramic sheet. A plurality of the obtained ceramic sheets were laminated so as to have a thickness of 500 μm to obtain a laminated ceramic sheet.
(Cutting conditions)
Cutting temperature: 60 ° C., cutting depth (remaining amount from the table surface): about 20 μm
Cutting blade: “U-BLADE2” manufactured by UHT, blade thickness: 50 μm, blade edge angle: 15 °

(7) Cut surface cut property evaluation In the same manner as in the above (6), the multilayer ceramic sheet was cut into a square shape so as to be a small piece of 1 mm x 0.5 mm. Select any 10 pieces from among the cut pieces, observe the cut surface with a magnifying glass at 50 magnification, check for chipping (lamination of the laminated ceramic sheet generated by the cutting process), and check the chipping generated in 10 pieces. The average of the total number was used as an index. The index is 0 to less than 10 places, ◎, 10 to less than 20 places, ◯, 20 to less than 40 places, and 40 or more places to x.

The polymer preparation method is described below. In addition, unless it refuses with a part here, let it be a weight part.
[Production Example 1] Preparation of polymer 1 In toluene, 100 parts of butyl acrylate, 5 parts of acrylic acid, and 0.2 part of benzoyl peroxide as a polymerization initiator were added and then heated to prepare an acrylic copolymer. A toluene solution of the combined polymer 1 was obtained.

[Production Example 2] Preparation of polymer 2 In toluene, 30 parts of 2-ethylhexyl acrylate, 70 parts of ethyl acrylate, 4 parts of 2-hydroxyethyl acrylate, 5 parts of N-phenylmaleimide, and peroxide as a polymerization initiator After adding 0.2 part of benzoyl, the mixture was heated to obtain a toluene solution of an acrylic copolymer (polymer 2).

[Production Example 3] Preparation of polymer 3 In toluene, 30 parts of 2-ethylhexyl acrylate, 70 parts of ethyl acrylate, 4 parts of 2-hydroxyethyl acrylate, 5 parts of methyl methacrylate, and benzoyl peroxide 0 as a polymerization initiator After adding 2 parts, the mixture was heated to obtain a toluene solution of an acrylic copolymer (polymer 3).

[Production Example 4] Preparation of polymer 4 In toluene, 50 parts of butyl acrylate, 50 parts of ethyl acrylate, 5 parts of acrylic acid, 0.1 part of 2-hydroxyethyl acrylate, and benzoyl peroxide 0 as a polymerization initiator After adding 2 parts, the mixture was heated to obtain a toluene solution of an acrylic copolymer (polymer 4).

[Production Example 5] Preparation of polymer 5 In ethyl acetate, 70 parts of methyl acrylate, 30 parts of 2-ethylhexyl acrylate, 10 parts of acrylic acid and 0.2 part of benzoyl peroxide as a polymerization initiator were added. To obtain an ethyl acetate solution of an acrylic copolymer (Polymer 5).

[Production Example 6] Preparation of polymer 6 In toluene, 50 mol of butyl acrylate, 50 mol of ethyl acrylate, 22 mol of 2-hydroxyethyl acrylate, and benzoyl peroxide (butyl acrylate, ethyl acrylate and 2-hydroxyethyl acrylate) as a polymerization initiator. After adding 0.2 part) to a total of 100 parts of hydroxyethyl acrylate, the mixture was heated to obtain a copolymer solution. To this copolymer solution was added 2-isocyanatoethyl acrylate in an amount corresponding to 80 mol% of the hydroxyl groups derived from 2-hydroxyethyl acrylate in the solution, and then heated to derive the 2-hydroxyethyl acrylate By adding 2-isocyanatoethyl methacrylate to the hydroxyl group, a toluene solution of an acrylic copolymer (polymer 6) having a methacrylate group in the side chain was obtained.

[Production Example 7] Preparation of polymer 7 In toluene, 80 moles of butyl acrylate, 30 moles of acryloyl morpholine, 20 moles of 2-hydroxyethyl acrylate, and benzoyl peroxide (butyl acrylate, acryloyl morpholine and 2-mol. After adding 0.2 part) to a total of 100 parts of hydroxyethyl acrylate, the mixture was heated to obtain a copolymer solution. To this copolymer solution, 2-isocyanatoethyl acrylate in an amount corresponding to 50 mol% of the hydroxyl groups derived from 2-hydroxyethyl acrylate in the solution was added, and then heated to derive from the 2-hydroxyethyl acrylate By adding 2-isocyanatoethyl methacrylate to the hydroxyl group, a toluene solution of an acrylic copolymer (polymer 7) having a methacrylate group in the side chain was obtained.

[Example 1]
(Formation of adhesive region precursor layer)
Toluene solution of polymer 2 prepared in Production Example 2 (polymer 2: 100 parts), 1 part of an isocyanate-based crosslinking agent (trade name “Coronate L”, manufactured by Nippon Polyurethane Co., Ltd.), and a terpene phenol resin ( Sumitomo Bakelite Co., Ltd., trade name “Sumilite Resin PR12603” 5 parts, thermally expandable microspheres (Matsumoto Yushi Seiyaku Co., Ltd., trade name “Matsumoto Microsphere F-50D”, foaming (expansion) start temperature: 95 (40 ° C. to 105 ° C., maximum expansion temperature: 125 ° C. to 135 ° C., average particle size: 10 μm to 18 μm) were mixed to prepare a mixed solution. The same solvent (toluene) as the solvent in the mixed solution was further added to the mixed solution to adjust the viscosity to a viscosity that was easy to apply. This mixed solution is applied to a polyethylene terephthalate film with a silicone release agent-treated surface (trade name “MRF38”, manufactured by Mitsubishi Chemical Polyester Film Co., Ltd., thickness: 38 μm) so that the thickness after solvent evaporation (drying) is 10 μm. And then dried to form an adhesive region precursor layer on the polyethylene terephthalate film.
(Formation of coating material region precursor layer)
A toluene solution of polymer 1 prepared in Production Example 1 (polymer 1: 100 parts) and a mixture of dipentaerythritol pentaacrylate and hexaacrylate as an active energy ray-reactive oligomer (trade name “Aronix M404” manufactured by Toagosei Co., Ltd.) ) 20 parts, 2 parts of an isocyanate-based crosslinking agent (trade name “Coronate L” manufactured by Nippon Polyurethane Co., Ltd.) and 3 parts of energy ray polymerization initiator (trade name “Irgacure 651” manufactured by BASF Japan Ltd.) To prepare a mixed solution. The same solvent (toluene) as the solvent in the mixed solution was further added to the mixed solution to adjust the viscosity to a viscosity that was easy to apply. Apply to a polyethylene terephthalate film with a silicone release agent-treated surface (Mitsubishi Chemical Polyester Film, trade name “MRF38”, thickness: 38 μm) using an applicator so that the thickness after solvent evaporation (drying) is 25 μm. Then, it was dried to form a coating material region precursor layer on the polyethylene terephthalate film.
(Formation of adhesive sheet 1)
The pressure-sensitive adhesive region precursor layer and the coating material region precursor layer were bonded together. Next, using an ultraviolet irradiator “UM810 (high pressure mercury lamp light source)” (manufactured by Nitto Seiki Co., Ltd.), ultraviolet irradiation with an integrated light amount of 300 mJ / cm 2 was performed from the precursor layer side of the coating material region. Then, the polyethylene terephthalate film with a silicone release agent-treated surface was peeled off to obtain a pressure-sensitive adhesive sheet 1 (pressure-sensitive adhesive region thickness: 10 μm, covering material region thickness: 25 μm).

[Examples 2 to 15, Comparative Example 1]
The type of polymer, cross-linking agent, tackifier, and thermally expandable microsphere when forming the pressure-sensitive adhesive region precursor layer and the amount of the compound are set as shown in Table 1, and the polymer when forming the coating material region precursor layer A pressure-sensitive adhesive sheet was obtained in the same manner as in Example 1 except that the types and blending amounts of the active energy ray-reactive oligomer, the crosslinking agent and the energy ray polymerization initiator were set as shown in Table 1.
In Examples 2 to 5, 8, 10, 13 to 15 and Comparative Example 1, a PET film (thickness) was used instead of the polyethylene terephthalate film with a silicone release agent-treated surface when forming the coating material region precursor layer. : 100 μm), the mixed solution was applied to obtain an adhesive sheet having a PET film (base material) without peeling off the PET film. Moreover, in Example 4 and Comparative Example 1, the adhesive sheet was obtained without performing ultraviolet irradiation.
The details of the crosslinking agent, tackifier, thermally expandable microsphere, active energy ray reactive oligomer, and energy ray polymerization initiator described in Table 1 are as follows.
<Crosslinking agent>
Tetrad C: Mitsubishi Gas Chemical Company, trade name “Tetrad C”, epoxy cross-linking agent <tackifier>
PR51732: Product name “Sumilite Resin PR51732” manufactured by Sumitomo Bakelite Co., Ltd.
S145: Product name “YS Polystar S145” manufactured by Yasuhara Chemical Co., Ltd.
U130: Product name “YS Polystar U130” manufactured by Yasuhara Chemical Co., Ltd.
T160: Yasuhara Chemical Co., Ltd., trade name “YS Polystar T160”
<Thermal expandable microsphere>
F-30D: Matsumoto Yushi Seiyaku Co., Ltd., trade name “Matsumoto Microsphere F-30D”, foaming (expansion) start temperature: 70 ° C. to 80 ° C., maximum expansion temperature: 110 ° C. to 120 ° C., average particle size 10 μm to 18 μm
F-65D: manufactured by Matsumoto Yushi Seiyaku Co., Ltd., trade name “Matsumoto Microsphere F-65D”, foaming (expansion) start temperature: 105 ° C. to 115 ° C., maximum expansion temperature: 145 ° C. to 155 ° C., average particle size 12 μm to 18 μm
FN-180SSD: manufactured by Matsumoto Yushi Seiyaku Co., Ltd., trade name “Matsumoto Microsphere FN-180SSD”, foaming (expansion) start temperature: 135 ° C. to 150 ° C., maximum expansion temperature: 165 ° C. to 180 ° C., average particle size 15 μm to 25 μm
F-260D: Matsumoto Yushi Seiyaku Co., Ltd., trade name “Matsumoto Microsphere F-260D”, foaming (expansion) start temperature: 190 ° C. to 200 ° C., maximum expansion temperature: 250 ° C. to 260 ° C., average particle size 20 μm to 35 μm
<Active energy ray reactive oligomer>
UV1700B: manufactured by Nippon Synthetic Chemical Co., Ltd., trade name “purple light UV-1700B”, UV curable urethane acrylate UV7620EA: manufactured by Nippon Synthetic Chemical Co., Ltd., trade name “purple UV-7620EA”, UV curable urethane acrylate UV3000B: Nippon Synthetic Chemical Co., Ltd. Product name “purple light UV-3000B”, UV curable urethane acrylate M321: manufactured by Toagosei Co., Ltd., product name “Aronix M321”, trimethylolpropane PO-modified triacrylate (average added moles of propylene oxide (PO): 2) Mole)
UV7630B: manufactured by Nippon Synthetic Chemical Co., Ltd., trade name “purple light UV-7630B”, UV curable urethane acrylate <energy ray polymerization initiator>
I184: BASF Corporation, trade name “Irgacure 184”
I2959: BASF, trade name “Irgacure 2959”
I6511: BASF, trade name “Irgacure 651”

[Example 16]
Toluene solution of polymer 1 prepared in Production Example 1 (polymer 1: 100 parts), epoxy-based cross-linking agent (manufactured by Mitsubishi Gas Chemical Company, trade name “Tetrad C”) 0.8 parts, and terpene as a tackifier 30 parts of phenolic resin (trade name “YS Polystar S145” manufactured by Yashara Chemical Co., Ltd.) and thermally expandable microspheres (trade name “Matsumoto Microsphere F-50D” manufactured by Matsumoto Yushi Seiyaku Co., Ltd.), foaming (expansion) start temperature : 95 ° C. to 105 ° C., maximum expansion temperature: 125 ° C. to 135 ° C., average particle size of 10 μm to 18 μm) was mixed with 30 parts to prepare a mixed solution. The same solvent (toluene) as the solvent in the mixed solution was further added to the mixed solution to adjust the viscosity to a viscosity that was easy to apply. This mixed solution is applied to a polyethylene terephthalate film with a silicone release agent-treated surface (trade name “MRF38”, thickness: 38 μm, manufactured by Mitsubishi Chemical Polyester Film Co., Ltd.) so that the thickness after solvent evaporation (drying) is 30 μm. And then dried to form an adhesive region precursor layer on the polyethylene terephthalate film.
The pressure-sensitive adhesive surface of the pressure-sensitive adhesive region precursor layer was bonded to a mat-treated surface of a polyethylene terephthalate film (trade name “Lumirror type X42”, manufactured by Toray Industries, Inc., thickness: 50 μm) as a coating material region with a hand roller. An autoclaving treatment (40 ° C., 5 kgf / cm 2, 10 minutes) gave an adhesive sheet (adhesive region (thickness: 30 μm) / covering material region (polyethylene terephthalate, thickness: 50 μm)).

[Example 17]
Toluene solution of polymer 4 prepared in Production Example 4 (polymer 4: 100 parts), epoxy cross-linking agent (trade name “Tetrad C” manufactured by Mitsubishi Gas Chemical Co., Ltd.) 0.8 parts, and terpene as a tackifier 5 parts of phenolic resin (trade name “YS Polystar S145” manufactured by Yashara Chemical Co., Ltd.) and thermally expandable microspheres (trade name “Matsumoto Microsphere F-50D” manufactured by Matsumoto Yushi Seiyaku Co., Ltd.), foaming (expansion) start temperature : 95 ° C. to 105 ° C., maximum expansion temperature: 125 ° C. to 135 ° C., average particle diameter of 10 μm to 18 μm) was mixed with 30 parts to prepare a mixed solution. The same solvent (toluene) as the solvent in the mixed solution was further added to the mixed solution to adjust the viscosity to a viscosity that was easy to apply. This mixed solution is applied to a polyethylene terephthalate film with a silicone release agent-treated surface (trade name “MRF38”, thickness: 38 μm, manufactured by Mitsubishi Chemical Polyester Film Co., Ltd.) so that the thickness after solvent evaporation (drying) is 40 μm. And then dried to form an adhesive region precursor layer on the polyethylene terephthalate film.
A mixed solvent of ethyl acetate and dimethylformamide (acetic acid) with a wire bar (10th) on one side of a polyethylene terephthalate film (Mitsubishi Resin Diafix (PG-CHI (FG, thickness 200 μm)) as a coating material region. Ethyl: dimethylformamide = 1: 10 (volume%) was applied, and the adhesive surface of the adhesive region precursor layer was bonded to the coated surface with a hand roller, and dried with a hot air dryer at 80 ° C. for 3 minutes. Thus, an adhesive sheet (adhesive region (thickness: 40 μm) / covering region (polyethylene terephthalate, thickness: 200 μm)) was obtained.

As is apparent from Table 1, the pressure-sensitive adhesive sheet of the present invention can reduce the adhesive strength by heating, and can achieve excellent cutting accuracy when the adherend is cut.

The production method and pressure-sensitive adhesive sheet of the present invention can be suitably used for the production of chip-shaped electronic components such as semiconductor chips.

DESCRIPTION OF SYMBOLS 10 Adhesive area | region 11 Adhesive surface 12 Adhesive 13 Thermally expansible microsphere 20 Coating | covering material area | region 30 Base material 100,200 Adhesive sheet

Claims

It has an adhesive surface whose adhesive strength is reduced by heating, only on one side,
The elastic modulus of the surface opposite to the adhesive surface by a nanoindentation method at 25 ° C. is 1 MPa or more.
Adhesive sheet.
In a cross-sectional view, it has a pressure-sensitive adhesive region including the pressure-sensitive adhesive surface as a surface, and a covering material region adjacent to the pressure-sensitive adhesive region opposite to the pressure-sensitive adhesive surface,
The adhesive region comprises an adhesive and thermally expandable microspheres;
The pressure-sensitive adhesive sheet according to claim 1.
The pressure-sensitive adhesive sheet according to claim 1 or 2, wherein the pressure-sensitive adhesive region has a thickness of 50 µm or less.
The pressure-sensitive adhesive sheet according to any one of claims 1 to 3, wherein the pressure-sensitive adhesive strength when the pressure-sensitive adhesive side is bonded to a polyethylene terephthalate film is 0.2 N / 20 mm or more.
The pressure-sensitive adhesive according to any one of claims 1 to 4, wherein a ratio (a2 / a1) between the pressure-sensitive adhesive force (a1) before heating and the pressure-sensitive adhesive force (a2) after heating is 0.0001 to 0.5. Sheet.
The pressure-sensitive adhesive sheet according to any one of claims 1 to 5, wherein the surface roughness Ra of the pressure-sensitive adhesive surface after heating is 3 µm or more.
The pressure-sensitive adhesive sheet according to any one of claims 1 to 6, further comprising a base material on a side opposite to the pressure-sensitive adhesive surface.
After sticking an electronic component material on the pressure-sensitive adhesive sheet according to claim 1,
Cutting the electronic component material,
Manufacturing method of electronic components.