Adhesive sheet

Abstract

Provided is an adhesive sheet that combines excellent adhesiveness and releasability and has excellent visual recognition of the adherend (visual recognition through the adhesive sheet). The adhesive sheet of the present invention comprises a gas generating layer that generates gas by laser irradiation, and the haze value is 50% or less. In one embodiment, the thickness of the gas generating layer is 0.1 μm to 50 μm. In one embodiment, the gas generating layer is a layer that absorbs ultraviolet rays. In one embodiment, the gas generating layer contains an ultraviolet absorber.

Description

Technical Field

[0001] The present invention relates to an adhesive sheet. Background Art

[0002] In the past, when electronic component was handled (processing), sometimes performed as follows: when processing, processed object was temporarily fixed to fixed platform by adhesive sheet, after processing, processed object was peeled off from this adhesive sheet.As the adhesive sheet used in such operation, sometimes use the adhesive sheet that has the adhesive force of regulation when processing, after processing, adhesive force can descend.As one of such adhesive sheet, proposed to make in the adhesive layer contain heat-expandable microsphere and the adhesive sheet (for example patent documentation 1) that constitutes. The adhesive sheet that contains heat-expandable microsphere has following features: have the adhesive force of regulation, and by utilizing heating, heat-expandable microsphere is expanded, on bonding surface, forms concavo-convex and reduces contact area, and adhesive force descends or disappears thus.Such adhesive sheet has the advantage that does not have external stress and just can easily peel off processed object.

[0003] However, the light transmittance of a pressure-sensitive adhesive sheet containing heat-expandable microspheres is low, and when using such a pressure-sensitive adhesive sheet, a problem arises in that a mark provided on a fixing table to indicate the temporary fixing position of an electronic component is difficult to visually recognize through the pressure-sensitive adhesive sheet.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 2001-131507 Summary of the Invention

[0007] Problems to be solved by the invention

[0008] The present invention has been made to solve the above-mentioned conventional problems, and an object thereof is to provide a PSA sheet that combines excellent adhesiveness and releasability and has excellent adherend visibility (visibility through the PSA sheet).

[0009] Solutions for solving problems

[0010] The pressure-sensitive adhesive sheet of the present invention includes a gas-generating layer that generates gas upon laser irradiation, and has a haze value of 50% or less.

[0011] In one embodiment, the gas generation layer has a thickness of 0.1 μm to 50 μm.

[0012] In one embodiment, the gas generation layer is a layer capable of absorbing ultraviolet rays.

[0013] In one embodiment, the gas generation layer contains an ultraviolet absorber.

[0014] In one embodiment, the pressure-sensitive adhesive sheet has an ultraviolet transmittance of 30% or less at a wavelength of 360 nm.

[0015] In one embodiment, the pressure-sensitive adhesive sheet has an ultraviolet transmittance of 50% to 100% at a wavelength of 500 nm.

[0016] In one embodiment, the gas generating layer is a layer that generates hydrocarbon-based gas.

[0017] In one embodiment, the gasification starting temperature of the gas generation layer is 150°C to 500°C.

[0018] In one embodiment, the pressure-sensitive adhesive sheet has a 10% weight loss temperature of 200°C to 500°C.

[0019] In one embodiment, the pressure-sensitive adhesive sheet further includes a pressure-sensitive adhesive layer on at least one side of the gas generation layer, wherein the pressure-sensitive adhesive layer is a layer whose surface is deformed by laser irradiation of the pressure-sensitive adhesive sheet.

[0020] In one embodiment, the adhesive layer has a thickness of 0.1 μm to 50 μm.

[0021] In one embodiment, the pressure-sensitive adhesive layer is foamed by irradiating the pressure-sensitive adhesive sheet with laser light.

[0022] According to another aspect of the present invention, there is provided a method for processing an electronic component, comprising: attaching the electronic component to the adhesive sheet; and irradiating the adhesive sheet with laser light to peel the electronic component from the adhesive sheet.

[0023] In one embodiment, the electronic component is peeled off at selected locations.

[0024] In one embodiment, the treatment method includes performing a predetermined treatment on the electronic component after attaching the electronic component to the adhesive sheet and before peeling the electronic component from the adhesive sheet.

[0025] In one embodiment, the processing is grinding, dicing, chip bonding, wire bonding, etching, evaporation, molding, circuit formation, inspection, product testing, cleaning, transfer, alignment, repair, or protection of the device surface.

[0026] According to another aspect of the present invention, there is provided a method for handling an electronic component, comprising: peeling the electronic component from the adhesive sheet and then placing the electronic component on another sheet.

[0027] Effects of the Invention

[0028] According to the present invention, a PSA sheet can be provided that combines excellent adhesiveness and releasability and exhibits excellent adherend visibility (visibility through the PSA sheet). BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a schematic cross-sectional view of a pressure-sensitive adhesive sheet according to one embodiment of the present invention.

[0030] Figure 2 This is a schematic cross-sectional view of a pressure-sensitive adhesive sheet according to another embodiment of the present invention.

[0031] Figure 3 Schematic diagram illustrating the method for measuring puncture strength. DETAILED DESCRIPTION

[0032] A. Overview of PSA Sheet

[0033] Figure 1 (a) is a schematic cross-sectional view of an adhesive sheet according to one embodiment of the present invention. Adhesive sheet 100 includes a gas generating layer 10. Gas generating layer 10 generates gas by laser irradiation. More specifically, gas generating layer 10 is a layer that generates gas by gasifying its components by laser irradiation. A UV laser is typically used as the laser. Gas generating layer 10 may have a predetermined adhesive force.

[0034] Figure 1 (b) is a schematic cross-sectional view of an adhesive sheet according to another embodiment of the present invention. Adhesive sheet 100' comprises a gas generation layer 10 and at least one adhesive layer 20 disposed on one side of the gas generation layer 10. The adhesive layer 20 can be deformed by irradiating the adhesive sheet (substantially the gas generation layer) with a laser. In one embodiment, the deformation is caused by gas generated from the gas generation layer 10 and can occur on the side of the adhesive layer 20 opposite to the gas generation layer 10.

[0035] The adhesive sheet of the present invention can be used by attaching an object to be processed, such as an electronic component, to a gas generating layer or an adhesive layer. The adhesive sheet of the present invention is provided with a gas generating layer, and gas is generated locally in a small range by laser irradiation. By such gas generation, deformation of the attachment surface is generated, and as a result, the adherend can be well peeled off. When the adhesive sheet is provided with an adhesive layer, as described above, deformation is generated in the adhesive layer due to the gas generation, and as a result, peelability is exhibited in the portion irradiated by the laser. Typically, the laser is irradiated from the side of the gas generating layer opposite to the adhesive layer. According to the present invention, since deformation can be generated in a small range by the above operation, the small electronic component can be well peeled off even when extremely fine small electronic components are processed (processed). In addition, even if a small electronic component to be peeled off is temporarily fixed adjacent to a small electronic component that does not need to be peeled off, peeling can be performed at the portion to be peeled off, and peeling is not performed at the portion outside the portion to be peeled off, that is, only the small electronic component to be peeled off can be peeled off, and unnecessary detachment of the small electronic component can be prevented. In order to facilitate deformation of the adhesive layer, it is preferable to block at least a portion of the generated gas so as not to escape from the adhesive sheet. The adhesive layer can function as a gas barrier layer.

[0036] The so-called deformation of the adhesive layer refers to the displacement generated in the normal direction (thickness direction) and the horizontal direction (direction orthogonal to the thickness direction) of the adhesive layer. The deformation of the adhesive layer is generated, for example, by using a UV laser with a wavelength of 355nm and a beam diameter of about 20μmφ, performing pulse scanning at 0.80mW power and 40kHz frequency, thereby generating gas from the gas generating layer. Regarding the deformed shape, for example, for any one point that has been pulse scanned, 24 hours after laser irradiation, it is observed based on the measurement of a confocal laser microscope or a non-contact interference microscope (WYKO). Its shape can be foaming (convex), through-hole (concave-convex), or concave (concave), and these deformations can produce peeling properties. When the electronic component is to be effectively peeled off along the normal direction, it is preferred that the displacement change in the normal direction before and after laser irradiation is large, and the one forming a foaming shape is particularly suitable. The foaming (convex) is based on the surface of the adhesive sheet of the unirradiated portion, and the highest point is defined as the vertical displacement Y, and the full width at half maximum is defined as the horizontal displacement X (diameter). For through-holes (convex and concave) and depressions (concave) formed after laser irradiation, the difference between the highest and lowest points is defined as the vertical displacement Y, and the diameter of the hole is defined as the horizontal displacement X. Hereinafter, the portion deformed by laser irradiation will also be referred to as the "deformed portion."

[0037] Figure 2Schematic cross-sectional view of an adhesive sheet according to another embodiment of the present invention. The adhesive sheet 200 further comprises an intermediate layer 30 between the gas generating layer 10 and the adhesive layer 20. By providing the intermediate layer, the deformation of the adhesive layer can be easily controlled (described in detail later). In addition, the intermediate layer can cooperate with the adhesive layer to act as a gas barrier layer. Therefore, by providing the intermediate layer, the gas barrier properties are improved, and an adhesive sheet in which the adhesive layer is more preferably deformed can be obtained. The intermediate layer can be a single layer or a multilayer.

[0038] Although not shown, the adhesive sheet may further include other layers. For example, a substrate or another adhesive layer may be provided on the side of the gas generating layer opposite to the adhesive layer. The substrate may be, for example, a film formed from any suitable resin.

[0039] The adhesive sheet of the present invention is characterized in that the haze value is 50% or less. In the present invention, the gas generating layer, the adhesive layer and the intermediate layer can be formed without containing insoluble fillers, etc., so that an adhesive sheet with a small haze value, high light transmittance and suppressed white turbidity can be obtained. The above-mentioned adhesive sheet has high transparency before laser irradiation (when temporarily fixed). When such an adhesive sheet is used, for example, the adherend (for example, a table for temporarily fixing electronic components) can be visually identified through the adhesive sheet, and for example, a mark provided on the fixing table to indicate the temporary fixing position of the electronic component can be satisfactorily visually identified through the adhesive sheet. Such an effect is an excellent effect that cannot be obtained by an adhesive sheet containing an insoluble filler (for example, an adhesive sheet containing heat-expandable microspheres in an adhesive layer serving as a releasable display layer).

[0040] The haze value of the pressure-sensitive adhesive sheet of the present invention is preferably 0% to 50%, more preferably 0.01% to 40%, even more preferably 0.05% to 30%, and particularly preferably 0.1% to 20%. Within these ranges, the above-mentioned effects of the present invention become more pronounced.

[0041] The adhesive layer of the adhesive sheet of the present invention preferably has an adhesive force of 0.1N / 20mm or more relative to SUS430, more preferably 0.2N / 20mm to 50N / 20mm, further preferably 0.5N / 20mm to 40N / 20mm, particularly preferably 0.7N / 20mm to 20N / 20mm, and most preferably 1N / 20mm to 10N / 20mm. If it is within such a range, an adhesive sheet that exhibits good adhesiveness as a temporary fixing sheet used in the manufacture of electronic components can be obtained. In this specification, the so-called adhesive force refers to the adhesive force measured by the method according to JIS Z 0237:2000 (lamination conditions: 2 kg roller 1 round trip, tensile speed: 300mm / min, peeling angle 180°) under an environment of 23°C.

[0042] In one embodiment, the gas-generating layer has a predetermined adhesive strength. The gas-generating layer of the adhesive sheet of the present invention preferably has an adhesive strength of 0.1 N / 20 mm or greater to SUS430, more preferably 0.5 N / 20 mm to 50 N / 20 mm, even more preferably 1 N / 20 mm to 40 N / 20 mm, particularly preferably 1.5 N / 20 mm to 30 N / 20 mm, and most preferably 2 N / 20 mm to 20 N / 20 mm. Within this range, an adhesive sheet exhibiting excellent adhesive properties can be obtained, for example, as a temporary fixing sheet used in the manufacture of electronic components.

[0043] The thickness of the pressure-sensitive adhesive sheet of the present invention is preferably 2 μm to 200 μm, more preferably 3 μm to 150 μm, and even more preferably 5 μm to 120 μm.

[0044] The water vapor permeability of the adhesive sheet of the present invention is preferably 5000 g / (m 2 ·day) or less, more preferably 4800g / (m 2 ·day) or less, more preferably 4500g / (m 2 ·day) or less, more preferably 4200g / (m 2 ·day) or less. An adhesive sheet having an adhesive layer (and an intermediate layer as needed) with a water vapor permeability in such a range can prevent the escape of gas generated by laser irradiation and can form a deformed portion with an excellent shape in the adhesive layer. If such an adhesive sheet is used, small adherends (for example, electronic components) can be peeled off with good precision. The smaller the water vapor permeability of the adhesive sheet of the present invention, the more preferably, and its lower limit is, for example, 0.1 g / (m 2 The water vapor transmission rate can be measured in an atmosphere of 30° C. and 90% RH by a measurement method in accordance with JIS K7129B.

[0045] The water vapor permeability of the laminate comprising the adhesive layer and the intermediate layer is preferably 10000 g / (m 2 ·day) or less, more preferably 7000g / (m 2 ·day) or less, more preferably 5000g / (m 2 ·day) or less, more preferably 4800g / (m 2 ·day) or less, particularly preferably 4500g / (m 2 ·day) or less, and most preferably 4200g / (m 2·day) or less. When it is within such a range, the laminate comprising the adhesive layer and the intermediate layer functions well as a gas barrier layer, and a deformed portion of excellent shape is formed in the adhesive layer. If such an adhesive sheet is used, small adherends (such as electronic components) can be peeled off with good precision. The smaller the water vapor permeability of the laminate comprising the adhesive layer and the intermediate layer, the more preferable it is, and its lower limit is, for example, 1 g / (m 2 ·day).

[0046] The puncture strength of the laminate comprising the above-mentioned adhesive layer and the intermediate layer is preferably 10mN to 5000mN, more preferably 30mN to 4000mN, further preferably 50mN to 3000mN, and particularly preferably 100mN to 2000mN. Within such a range, the laminate comprising the adhesive layer and the intermediate layer functions well as a gas barrier layer, and satisfactorily produces shape changes based on gas generation, resulting in a deformed portion of excellent shape formed in the adhesive layer. If such an adhesive sheet is used, small adherends (such as electronic components) can be peeled off with good precision. Puncture strength such as Figure 3 As shown, a compression tester 6 (manufactured by Kato Tech, trade name "KES-G5") is used to measure the strength of a sample 4 (e.g., a laminate) by clamping it between sample holders 5A and 5B having a circular opening with a diameter of 11.28 mm. More specifically, a puncture needle (curvature radius: 1 mm) is inserted into the sample at the center of the circular opening at a measurement temperature of 23°C (puncture speed: 0.1 mm / s), and the maximum load at the rupture point is determined as the puncture strength.

[0047] The ultraviolet transmittance of the laminate including the pressure-sensitive adhesive layer and the intermediate layer at a wavelength of 360 nm is preferably 50% to 100%, more preferably 60% to 95%.

[0048] The UV transmittance of the adhesive sheet at a wavelength of 360 nm is preferably 30% or less, more preferably 20% or less, even more preferably 15% or less, particularly preferably 10% or less, and most preferably 5% or less. The lower limit of the UV transmittance of the adhesive sheet at a wavelength of 360 nm is, for example, 0% (preferably 0.05%, more preferably 0.1%).

[0049] The ultraviolet transmittance of the pressure-sensitive adhesive sheet at a wavelength of 500 nm is preferably 50% to 100%, more preferably 60% to 99%, further preferably 70% to 98%, and particularly preferably 80% to 97%.

[0050] The 10% weight loss temperature of the adhesive sheet is preferably 200°C to 500°C, more preferably 220°C to 450°C, even more preferably 250°C to 400°C, and particularly preferably 270°C to 370°C. Within this range, an adhesive sheet capable of forming a more favorable deformable portion upon laser irradiation can be obtained. The 10% weight loss temperature of the adhesive sheet refers to the temperature at which, in a TGA analysis of the adhesive sheet when heated, the sheet has decreased by 10% by weight relative to its pre-heating weight (i.e., the weight of the adhesive sheet is 90% of its pre-irradiation weight).

[0051] B. Gas generation layer

[0052] The gas generation layer may be a layer that can absorb ultraviolet rays. In one embodiment, the gas generation layer contains an ultraviolet absorber. By containing an ultraviolet absorber, a gas generation layer that can absorb laser light and gasify can be formed. Typically, the gas generation layer contains an ultraviolet absorber and an adhesive A. Preferably, the ultraviolet absorber is dissolved in the adhesive A and exists. If the ultraviolet absorber is dissolved in the adhesive A and exists, the following adhesive sheet can be obtained: a deformed portion (such as a concave-convex portion) can be generated at any part of the attachment surface (gas generation layer surface and / or adhesive layer surface), and the shape deviation of the deformed portion (such as a concave-convex portion) is small. If such an adhesive sheet is used, a deformed portion (such as a concave-convex portion) can be generated with good precision at the desired location, and the effect of the present invention becomes significant. It should be noted that, in this specification, the so-called "dissolved in the adhesive and exists" means that the ultraviolet absorber does not exist in the gas generation layer in the form of particles. More specifically, it is preferred that the gas generation layer does not contain an ultraviolet absorber with a particle size of 10 μm or more in the particle distribution measurement in the cross section of the gas generation layer based on X-ray CT. The gas generation layer may or may not contain components insoluble in the binder. In one embodiment, the presence and content of insoluble components in the gas generation layer are evaluated by the haze value of the gas generation layer. A lower haze value indicates a lower content of insoluble components in the gas generation layer. Preferably, the gas generation layer contains substantially no components insoluble in the binder.

[0053] The elastic modulus of the cross section of the gas generation layer obtained by nanoindentation is preferably 0.01MPa to 1000MPa, more preferably 0.05MPa to 800MPa. When it is within such a range, the shape change of the gas generation layer based on gas generation occurs satisfactorily, and as a result, a deformation portion with an excellent shape is formed on the attached surface (gas generation layer surface and / or adhesive layer surface). The elastic modulus obtained by nanoindentation refers to the elastic modulus obtained by continuously measuring the load and the indentation depth of the indenter when the indenter is pressed into the sample (for example, the adhesive surface) from the time of loading to the time of unloading, and the load-indentation depth curve obtained. The elastic modulus obtained by nanoindentation is obtained as follows: the displacement-load hysteresis curve obtained by pressing a diamond Berkovich-type (triangular pyramid-type) probe vertically on the cut cross section of the measurement object layer is numerically processed using the software (triboscan) included with the measuring device, thereby obtaining it. In this specification, the elastic modulus of the cross section obtained by the nanoindentation method is the elastic modulus measured by a single indentation method at a specified temperature (25°C) using a nanoindenter (Triboindenter TI-950 manufactured by Hysitron Inc.) under the measurement conditions of an indentation speed of about 500 nm / sec, a withdrawal speed of about 500 nm / sec, and an indentation depth of about 1500 nm. It should be noted that the elastic modulus of the gas generation layer can be adjusted by the type of material contained in the layer, the structure of the base polymer constituting the material, the type and amount of additives added to the layer, etc. It should be noted that in this specification, when the cross section or surface is not described and only the elastic modulus obtained by the nanoindentation method is recorded, the elastic modulus refers to the elastic modulus of the cross section obtained by the nanoindentation method.

[0054] The elastic modulus obtained by nanoindentation on the surface of the gas generation layer is preferably 0.01MPa to 1000MPa, more preferably 0.05MPa to 800MPa. If it is within such a range, the shape change of the gas generation layer based on gas generation occurs satisfactorily, and as a result, a deformation portion of excellent shape is formed in the adhesive layer. The so-called elastic modulus obtained by nanoindentation refers to the elastic modulus obtained by continuously measuring the load and the indentation depth of the indenter when the indenter is pressed into the sample (for example, the adhesive surface) from the time of loading until unloading, and the load-indentation depth curve obtained. The elastic modulus obtained by nanoindentation is obtained as follows: for the displacement-load hysteresis curve obtained by pressing a diamond Berkovich-type (triangular pyramid-type) probe vertically on the cut section of the measurement object layer, the software (triboscan) included with the measuring device is used for numerical processing, thereby obtaining. In this specification, the elastic modulus of the surface obtained by the nanoindentation method is the elastic modulus measured by a single indentation method at a specified temperature (25°C) using a nanoindenter (Triboindenter TI-950 manufactured by Hysitron Inc.) under the measurement conditions of an indentation speed of about 500 nm / sec, a withdrawal speed of about 500 nm / sec, and an indentation depth of about 3000 nm. It should be noted that the elastic modulus of the gas generation layer can be adjusted by the type of material contained in the layer, the structure of the base polymer constituting the material, the type and amount of additives added to the layer, etc. In the present invention, there is no significant difference between the elastic modulus obtained by the nanoindentation method measured by the above method using the cross section as the measurement surface and the elastic modulus obtained by the nanoindentation method measured by the above method using the surface as the measurement surface. In the case where it is difficult to measure from the cross section, the value measured from the surface can be used as the measurement value from the cross section.

[0055] The gasification starting temperature of the gas generation layer is preferably 150°C to 500°C, more preferably 170°C to 450°C, further preferably 190°C to 420°C, and particularly preferably 200°C to 400°C. If it is within this range, a pressure-sensitive adhesive sheet that can form a better deformation portion by laser irradiation can be obtained. It should be noted that, in this specification, the so-called gasification starting temperature of the gas generation layer refers to the gas generation starting temperature calculated based on EGA analysis when the pressure-sensitive adhesive sheet is heated. The gas generation starting temperature is defined by the temperature at which the half-value of the maximum gas generation peak of the EGA / MS spectrum obtained by EGA analysis is reached. The lower the gasification starting temperature, the lower the temperature at which gas generation starts during laser irradiation, and a sufficient amount of gas is generated even when laser irradiation is performed at a lower power. In one embodiment, the gasification starting temperature of the gas generation layer is equivalent to the gasification starting temperature of the ultraviolet absorber.

[0056] The 10% weight loss temperature of the gas generation layer is preferably 150°C to 500°C, more preferably 170°C to 450°C, and even more preferably 200°C to 400°C. Within this range, a PSA sheet capable of forming a more favorable deformation portion upon laser irradiation can be obtained. The 10% weight loss temperature of the gas generation layer refers to the temperature at which, when the PSA sheet is heated (e.g., heated by laser irradiation), the weight of the gas generation layer decreases by 10% by weight relative to its pre-heating weight (i.e., the weight of the gas generation layer reaches 90% of its pre-heating weight) as measured by TGA analysis.

[0057] The thickness of the gas generation layer is preferably 0.1 μm to 50 μm, more preferably 1 μm to 40 μm, further preferably 2 μm to 30 μm, and particularly preferably 5 μm to 20 μm. Within these ranges, a PSA sheet capable of forming a better deformable portion by laser irradiation can be obtained.

[0058] The elastic modulus Er(gas) [unit: MPa] and the thickness h(gas) [unit: μm] of the gas generation layer obtained by nanoindentation satisfy the following formula (1).

[0059] Log(Er(gas)×10 6 )≥8.01×h(gas) -0.116 ···(1)

[0060] In the present invention, by constructing the gas-generating layer to satisfy the above-mentioned formula (1), excessive deformation caused by gas generated from the gas-generating layer can be prevented, and the adhesive sheet can be deformed well by laser irradiation. By forming such a gas-generating layer, even without providing a thick barrier layer (adhesive layer) as a layer to prevent excessive deformation, it is possible to produce a small surface deformation. More specifically, the gas-generating layer itself can undergo surface deformation, or the adhesive layer (gas barrier layer) can be constructed to be flexible.

[0061] In one embodiment, the elastic modulus Er(gas) [unit: MPa] obtained by nanoindentation and the thickness h(gas) [unit: μm] satisfy the following formula (2). In one embodiment, the elastic modulus Er(gas) [unit: MPa] obtained by nanoindentation and the thickness h(gas) [unit: μm] satisfy the following formula (3).

[0062] Log(Er(gas)×10 6 )≥7.66×h(gas) -0.092 ···(2)

[0063] Log(Er(gas)×10 6)≥7.52×h(gas) -0.081 ···(3)

[0064] Within such a range, the above-mentioned effects become more significant.

[0065] In one embodiment, the elastic modulus Er(gas) [unit: MPa] and the thickness h(gas) [unit: μm] obtained by the nanoindentation method further satisfy the following formula (4).

[0066] Log(Er(gas)×10 6 )≤47.675×h(gas) -0.519 ···(4)

[0067] The gas generation layer preferably has an ultraviolet light transmittance of 360 nm or less, more preferably 20% or less, even more preferably 15% or less, particularly preferably 10% or less, and most preferably 5% or less. The lower limit of the ultraviolet light transmittance of the gas generation layer at 360 nm is, for example, 0% (preferably 0.05%, more preferably 0.1%).

[0068] The haze value of the gas generation layer is preferably 55% or less, more preferably 0.1% to 50%, and further preferably 0.5% to 40%. The haze value is an indicator of the compatibility between the binder (substantially the base polymer) and the ultraviolet absorber in the gas generation layer. The haze value is obtained by the ratio of diffusely transmitted light to the total transmitted light when light in the visible light region (wavelength: 380nm to 780nm) is incident. The wavelength of light is regarded as the smallest unit. When the concentration and composition are uniform when the wavelength size is larger than the wavelength size, the transparency is high, that is, the compatibility is high. When the concentration and composition are uneven, light scattering and white turbidity occur, that is, the compatibility becomes low. When the haze of the gas generation layer is within the above range, an adhesive sheet can be formed in which the ultraviolet absorber is not unevenly present. Such an adhesive sheet exhibits good releasability by laser irradiation.

[0069] B-1. Ultraviolet absorber

[0070] As the above-mentioned ultraviolet absorber, any appropriate ultraviolet absorber can be used as long as the effect of the present invention is obtained. As ultraviolet absorbers, for example, benzophenone ultraviolet absorbers, triazine ultraviolet absorbers, salicylate ultraviolet absorbers, cyanoacrylate ultraviolet absorbers, etc. can be listed. Among them, triazine ultraviolet absorbers are preferred. Especially when using an acrylic adhesive as adhesive A, triazine ultraviolet absorbers have high compatibility with the base polymer of the acrylic adhesive and can be preferably used. By using a triazine ultraviolet absorber, a gas generation layer with a small haze value can be formed. The triazine ultraviolet absorber is more preferably composed of a compound having a hydroxyl group, and is particularly preferably composed of an ultraviolet absorber consisting of a hydroxyphenyltriazine compound (hydroxyphenyltriazine ultraviolet absorber).

[0071] Examples of hydroxyphenyltriazine-based ultraviolet absorbers include the reaction product of 2-(4,6-bis(2,4-dimethylphenyl)-1,3,5-triazin-2-yl)-5-hydroxyphenyl and [(C10-C16 (mainly C12-C13) alkoxy)methyl]oxirane (trade name "TINUVIN 400", manufactured by BASF), 2-[4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine-2-yl]-5-[3-(dodecyloxy)-2-hydroxypropoxy]phenol, reaction product of 2-(2,4-dihydroxyphenyl)-4,6-bis-(2,4-dimethylphenyl)-1,3,5-triazine and glycidic acid (2-ethylhexyl) ester (trade name "TINUVIN 405", manufactured by BASF), 2,4-bis(2-hydroxy-4-butoxyphenyl)-6-(2,4-dibutoxyphenyl)-1,3,5-triazine (trade name "TINUVIN 460", manufactured by BASF), 2-(4,6-diphenyl-1,3,5-triazine-2-yl)-5-[(hexyl)oxy]phenol (trade name "TINUVIN 1577", manufactured by BASF), 2-(4,6-diphenyl-1,3,5-triazine-2-yl)-5-[2-(2-ethylhexanoyloxy)ethoxy]phenol (trade name "Adekastab LA-46", manufactured by ADEKA), 2-(2-hydroxy-4-[1-octyloxycarbonylethoxy]phenyl)-4,6-bis(4-phenylphenyl)-1,3,5-triazine (trade name "TINUVIN 479", manufactured by BASF), and trade name "TINUVIN 477" manufactured by BASF.

[0072] Examples of the benzotriazole-based ultraviolet absorber (benzotriazole-based compound) include 2-(2-hydroxy-5-tert-butylphenyl)-2H-benzotriazole (trade name "TINUVIN PS", manufactured by BASF), an ester compound of phenylpropionic acid and 3-(2H-benzotriazol-2-yl)-5-(1,1-dimethylethyl)-4-hydroxy (C7-9 side chain and linear alkyl) (trade name "TINUVIN 384-2", manufactured by BASF), a mixture of octyl 3-[3-tert-butyl-4-hydroxy-5-(5-chloro-2H-benzotriazol-2-yl)phenyl]propionate and 2-ethylhexyl 3-[3-tert-butyl-4-hydroxy-5-(5-chloro-2H-benzotriazol-2-yl)phenyl]propionate (trade name "TINUVIN 109", manufactured by BASF), 2-(2H-benzotriazol-2-yl)-4,6-bis(1-methyl-1-phenylethyl)phenol (trade name "TINUVIN 900", manufactured by BASF), 2-(2H-benzotriazol-2-yl)-6-(1-methyl-1-phenylethyl)-4-(1,1,3,3-tetramethylbutyl)phenol (trade name "TINUVIN 928", manufactured by BASF), methyl 3-(3-(2H-benzotriazol-2-yl)-5-tert-butyl-4-hydroxyphenyl)propionate / polyethylene glycol 300 reaction product (trade name "TINUVIN 1130", manufactured by BASF), 2-(2H-benzotriazol-2-yl)-4,6-bis(1-methyl-1-phenylethyl)phenol (trade name "TINUVIN 234", manufactured by BASF), 2-[5-chloro-2H-benzotriazol-2-yl]-4-methyl-6-(tert-butyl)phenol (trade name "TINUVIN 326", manufactured by BASF), 2-(2H-benzotriazol-2-yl)-4,6-di-tert-amylphenol (trade name "TINUVIN 328", manufactured by BASF), 2-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl)phenol (trade name "TINUVIN 329", manufactured by BASF), 2,2'-methylenebis[6-(2H-benzotriazole-2-yl)-4-(1,1,3,3-(3-(2H-benzotriazol-2-yl)-5-tert-butyl-4-hydroxyphenyl)propionic acid methyl ester and polyethylene glycol 300 reaction product (trade name "TINUVIN 213", manufactured by BASF), 2-(2H-benzotriazol-2-yl)-6-dodecyl-4-methylphenol (trade name "TINUVIN 571", manufactured by BASF), 2-[2-hydroxy-3-(3,4,5,6-tetrahydrophthalimide-methyl)-5-methylphenyl]benzotriazole (trade name "Sumisorb 250", manufactured by Sumitomo Chemical Co., Ltd.), 2-(3-tert-butyl-2-hydroxy-5-methylphenyl)-5-chloro-2H-benzotriazole (trade name "SEESORB 703", manufactured by Shipro Kasei Co., Ltd.), 2-(2H-benzotriazol-2-yl)-4-methyl-6-(3,4,5,6-tetrahydrophthalimidomethyl)phenol (trade name "SEESORB 706", manufactured by Shipro Kasei Co., Ltd.), 2-(4-benzoyloxy-2-hydroxyphenyl)-5-chloro-2H-benzotriazole (trade name "SEESORB 7012BA" manufactured by Shipro Kasei Co., Ltd.), 2-tert-butyl-6-(5-chloro-2H-benzotriazol-2-yl)-4-methylphenol (trade name "KEMISORB 73", manufactured by Chemipro Kasei Co., Ltd.), 2,2'-methylenebis[6-(2H-benzotriazol-2-yl)-4-tert-octylphenol] (trade name "Adekastab LA-31", manufactured by ADEKA Corporation), 2-(2H-benzotriazol-2-yl) para-cellulose (trade name "Adekastab LA-32", manufactured by ADEKA Corporation), 2-(5-chloro-2H-benzotriazol-2-yl)-6-tert-butyl-4-methylphenol (trade name "Adekastab LA-36", manufactured by ADEKA Corporation), etc.

[0073] In one embodiment, a UV absorber containing no halogen atoms is used. When such a UV absorber is used, a PSA sheet that is less likely to contaminate adherends such as electrodes can be obtained.

[0074] The molecular weight of the compound constituting the ultraviolet absorber is preferably 200 to 1500, more preferably 250 to 1200, and even more preferably 300 to 1000. Within these ranges, a pressure-sensitive adhesive sheet capable of forming a more favorable deformation portion by laser irradiation can be obtained.

[0075] The maximum absorption wavelength of the ultraviolet absorber is preferably 300 nm to 450 nm, more preferably 320 nm to 400 nm, and even more preferably 330 nm to 380 nm.

[0076] The content of the ultraviolet absorber is preferably 1 to 100 parts by weight, more preferably 1 to 50 parts by weight, and even more preferably 5 to 30 parts by weight, relative to 100 parts by weight of the gas generation layer. Within this range, a pressure-sensitive adhesive sheet capable of forming a more favorable deformation portion upon laser irradiation can be obtained.

[0077] B-2. Adhesive A

[0078] As the adhesive A contained in the gas generating layer, a pressure-sensitive adhesive A is preferably used. Examples of the adhesive A include acrylic adhesives, rubber adhesives, vinyl alkyl ether adhesives, silicone adhesives, polyester adhesives, polyamide adhesives, urethane adhesives, and styrene-diene block copolymer adhesives. Among these, acrylic adhesives or rubber adhesives are preferred, and acrylic adhesives are more preferred. It should be noted that the above adhesives may be used alone or in combination of two or more.

[0079] Examples of the acrylic pressure-sensitive adhesive include those containing, as a base polymer, an acrylic polymer (homopolymer or copolymer) using one or more kinds of (meth)acrylic acid alkyl esters as monomer components. Specific examples of the alkyl (meth)acrylate include C1-20 alkyl (meth)acrylates such as methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, sec-butyl (meth)acrylate, tert-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, undecyl (meth)acrylate, dodecyl (meth)acrylate, tridecyl (meth)acrylate, tetradecyl (meth)acrylate, pentadecyl (meth)acrylate, hexadecyl (meth)acrylate, heptadecyl (meth)acrylate, octadecyl (meth)acrylate, nonadecyl (meth)acrylate, and eicosyl (meth)acrylate. Among them, alkyl (meth)acrylates having a linear or branched alkyl group with 1 to 20 carbon atoms are preferably used, and alkyl (meth)acrylates having a linear or branched alkyl group with 2 to 20 carbon atoms are more preferably used.

[0080] In one embodiment, a (meth)acrylate alkyl ester A having a linear or branched alkyl group with 4 or more carbon atoms (preferably 4 to 20, more preferably 4 to 18) is used. An acrylic polymer formed using such a monomer and having a long side chain is advantageous in that it has a high affinity (compatibility) with an ultraviolet absorber. The content ratio of the above-mentioned (meth)acrylate alkyl ester A is preferably 30% by weight or more, more preferably 50% by weight or more, further preferably 70% by weight to 100% by weight, and particularly preferably 80% by weight to 100% by weight relative to all the constituent units constituting the acrylic polymer. When it is within such a range, the compatibility of the acrylic polymer with the ultraviolet absorber can be improved. The content ratio of the acrylic polymer containing the constituent units derived from the above-mentioned (meth)acrylate alkyl ester A is preferably 30 to 100 parts by weight, more preferably 70 to 100 parts by weight, relative to 100 parts by weight of the total amount of the acrylic polymer.

[0081] In one embodiment, a (meth)acrylate alkyl ester A having a linear or branched alkyl group with 4 or more carbon atoms (preferably 4 to 20, more preferably 4 to 18) and a triazine-based UV absorber are used in combination. The (meth)acrylate alkyl ester A and the triazine-based UV absorber have particularly excellent compatibility, and a PSA sheet having a gas-generating layer formed using these compounds exhibits significantly improved visual recognition.

[0082] The acrylic polymer may contain units corresponding to other monomer components copolymerizable with the alkyl (meth)acrylate, as required, for the purpose of modifying cohesion, heat resistance, crosslinking properties, etc. 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; acid anhydride monomers such as maleic anhydride and itaconic anhydride; hydroxyl group-containing monomers such as hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, hydroxyhexyl (meth)acrylate, hydroxyoctyl (meth)acrylate, hydroxydecyl (meth)acrylate, hydroxylauryl (meth)acrylate, and (4-hydroxymethylcyclohexyl)methyl methacrylate; styrenesulfonic acid, allylsulfonic acid, 2-(meth)acrylamido-2-methylpropanesulfonic acid, and (meth)acrylamidopropanesulfonic acid. , (meth)acrylate sulfopropyl, (meth)acryloyloxynaphthalenesulfonic acid and other sulfonic acid group-containing monomers; (meth)acrylamide, N,N-dimethyl (meth)acrylamide, N-butyl (meth)acrylamide, N-hydroxymethyl (meth)acrylamide, N-hydroxymethylpropane (meth)acrylamide and other (N-substituted) amide monomers; (meth)acrylate aminoalkyl ester monomers such as (meth)acrylate aminoethyl, (meth)acrylate N,N-dimethylaminoethyl, (meth)acrylate, tert-butylaminoethyl (meth)acrylate; (meth)acrylate alkoxyalkyl ester monomers such as (meth)acrylate methoxyethyl, (meth)acrylate ethoxyethyl; N-cyclohexyl acrylate Maleimide monomers such as imide, N-isopropylmaleimide, N-laurylmaleimide, and N-phenylmaleimide; itaconimide monomers such as N-methylitaconimide, N-ethylitaconimide, N-butylitaconimide, N-octylitaconimide, N-2-ethylhexylitaconimide, N-cyclohexylitaconimide, and N-laurylitaconimide; succinimide monomers such as N-(meth)acryloyloxymethylenesuccinimide, N-(meth)acryloyl-6-oxyhexamethylenesuccinimide, and N-(meth)acryloyl-8-oxyoctamethylenesuccinimide; vinyl acetate, vinyl propionate, and N- Vinyl monomers such as vinyl pyrrolidone, methyl vinyl pyrrolidone, vinyl pyridine, vinyl piperidone, vinyl pyrimidine, vinyl piperazine, vinyl pyrazine, vinyl pyrrole, vinyl imidazole, vinyl oxazole, vinyl morpholine, N-vinyl carboxylic acid amides, styrene, α-methylstyrene, and N-vinyl caprolactam; cyanoacrylate monomers such as acrylonitrile and methacrylonitrile; epoxy group-containing acrylic monomers such as glycidyl (meth)acrylate; glycol acrylate monomers such as polyethylene glycol (meth)acrylate, polypropylene glycol (meth)acrylate, methoxyethylene glycol (meth)acrylate, and methoxypolypropylene glycol (meth)acrylate;Acrylate monomers having heterocyclic rings, halogen atoms, silicon atoms, etc., such as tetrahydrofurfuryl (meth)acrylate, fluoro(meth)acrylate, and silicone (meth)acrylate; polyfunctional monomers such as 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(meth)acrylate, epoxy acrylate, polyester acrylate, and urethane acrylate; olefin monomers such as isoprene, butadiene, and isobutylene; and vinyl ether monomers such as vinyl ether. These monomer components may be used alone or in combination of two or more. Among these, from the viewpoint of high affinity (compatibility) with the ultraviolet absorber, preferably used are carboxyl group-containing monomers such as acrylic acid, methacrylic acid, carboxyethyl acrylate, carboxypentyl acrylate, itaconic acid, maleic acid, fumaric acid, and crotonic acid; acid anhydride monomers such as maleic anhydride and itaconic anhydride; and hydroxyl group-containing monomers such as hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, hydroxyhexyl (meth)acrylate, hydroxyoctyl (meth)acrylate, hydroxydecyl (meth)acrylate, hydroxylauryl (meth)acrylate, and (4-hydroxymethylcyclohexyl)methyl methacrylate. The proportion of these carboxyl group-containing monomers is preferably 0.5 to 15 parts by weight, more preferably 1 to 10 parts by weight, and even more preferably 3 to 9.5 parts by weight, relative to 100 parts by weight of the total amount of the acrylic polymer. The content of the acid anhydride monomer is preferably 0.5 to 15 parts by weight, more preferably 1 to 10 parts by weight, and even more preferably 3 to 9.5 parts by weight, relative to 100 parts by weight of the total amount of the acrylic polymer. The content of the hydroxyl-containing monomer is preferably 0.5 to 15 parts by weight, more preferably 1 to 10 parts by weight, and even more preferably 3 to 9.5 parts by weight, relative to 100 parts by weight of the total amount of the acrylic polymer.

[0083] Examples of the rubber-based adhesives include those using the following as base polymers: natural rubber; polyisoprene rubber, styrene-butadiene (SB) rubber, styrene-isoprene (SI) rubber, styrene-isoprene-styrene block copolymer (SIS) rubber, 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 (SEP) rubber, recycled rubber, butyl rubber, polyisobutylene, synthetic rubbers such as modified forms thereof, and the like.

[0084] The gas generated from the above-mentioned gas generation layer is preferably a hydrocarbon (preferably aliphatic hydrocarbon) gas. The gas generation layer that can generate hydrocarbon gas is composed of, for example, hydrocarbon compounds as the main component. The gas generation layer preferably does not contain halogen-containing compounds. If the generated gas is a hydrocarbon gas, corrosion of electronic components as the workpiece can be prevented. Such an effect is made more significant by forming a gas generation layer that does not contain halogen-containing compounds. The formula weight of the generated ions from the gas generation layer is preferably 10m / z to 800m / z, more preferably 11m / z to 700m / z, further preferably 12m / z to 500m / z, and particularly preferably 13m / z to 400m / z.

[0085] The adhesive A may contain any appropriate additives as needed. Examples of such additives include crosslinking agents, tackifiers (e.g., rosin-based tackifiers, terpene-based tackifiers, hydrocarbon-based tackifiers, etc.), plasticizers (e.g., trimellitate-based plasticizers, pyromellitate-based plasticizers), pigments, dyes, antioxidants, conductive materials, antistatic agents, light stabilizers, release modifiers, softeners, surfactants, flame retardants, and antioxidants.

[0086] Examples of the crosslinking agent include isocyanate crosslinking agents, epoxy crosslinking agents, melamine crosslinking agents, peroxide crosslinking agents, urea crosslinking agents, metal alkoxide crosslinking agents, metal chelate crosslinking agents, metal salt crosslinking agents, carbodiimide crosslinking agents, oxazoline crosslinking agents, aziridine crosslinking agents, and amine crosslinking agents. Among them, an isocyanate crosslinking agent or an epoxy crosslinking agent is preferred.

[0087] Specific examples of the isocyanate crosslinking agent include lower aliphatic polyisocyanates such as butylene diisocyanate and hexamethylene diisocyanate; alicyclic isocyanates such as cyclopentylene diisocyanate, cyclohexylene diisocyanate, and isophorone diisocyanate; aromatic isocyanates such as 2,4-toluene diisocyanate, 4,4'-diphenylmethane diisocyanate, and xylylenediisocyanate; and isocyanate adducts such as trimethylolpropane / toluene diisocyanate trimer adduct (manufactured by Nippon Polyurethane Industry Co., Ltd., trade name "Coronate L"), trimethylolpropane / hexamethylene diisocyanate trimer adduct (manufactured by Nippon Polyurethane Industry Co., Ltd., trade name "Coronate HL"), and isocyanurate of hexamethylene diisocyanate (manufactured by Nippon Polyurethane Industry Co., Ltd., trade name "Coronate HX"). The content of the isocyanate 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, more preferably 0.5 to 10 parts by weight, relative to 100 parts by weight of the base polymer.

[0088] Examples of the epoxy crosslinking agent include N,N,N',N'-tetraglycidyl-m-xylylenediamine, diglycidyl aniline, 1,3-bis(N,N-glycidylaminomethyl)cyclohexane (manufactured by Mitsubishi Gas Chemical Co., Ltd., trade name "Tetrad C"), 1,6-hexanediol diglycidyl ether (manufactured by Kyoeisha Chemical Co., Ltd., trade name "Epolight 1600"), neopentyl glycol diglycidyl ether (manufactured by Kyoeisha Chemical Co., Ltd., trade name "Epolight 1500NP"), ethylene glycol diglycidyl ether (manufactured by Kyoeisha Chemical Co., Ltd., trade name "Epolight 40E"), propylene glycol diglycidyl ether (manufactured by Kyoeisha Chemical Co., Ltd., trade name "Epolight 70P"), polyethylene glycol diglycidyl ether (manufactured by NOF Corporation, trade name "EPIOL E-400”), polypropylene glycol diglycidyl ether (manufactured by NOF Corporation, trade name “EPIOL P-200”), sorbitol polyglycidyl ether (manufactured by Nagase ChemteX, trade name “Denacol EX-611”), glycerol polyglycidyl ether (manufactured by Nagase ChemteX, trade name “Denacol EX-314”), pentaerythritol polyglycidyl ether, polyglycerol polyglycidyl ether (manufactured by Nagase ChemteX, trade name “Denacol EX-512”), sorbitan polyglycidyl ether, trimethylolpropane polyglycidyl ether, diglycidyl adipate, diglycidyl phthalate, triglycidyl tris(2-hydroxyethyl)isocyanurate, resorcinol diglycidyl ether, bisphenol-S-diglycidyl ether, epoxy resins having two or more epoxy groups in the molecule, and the like. The content of the epoxy 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, more preferably 0.03 to 5 parts by weight, relative to 100 parts by weight of the base polymer.

[0089] C. Adhesive layer

[0090] The adhesive layer contains any appropriate adhesive B. The adhesive B may be a pressure-sensitive adhesive B1 or a curable adhesive B2.

[0091] The thickness of the adhesive layer is preferably 0.1 μm to 50 μm, more preferably 0.5 μm to 40 μm, further preferably 1 μm to 30 μm, and particularly preferably 2 μm to 20 μm. Within these ranges, an adhesive layer having a preferred adhesive strength and functioning well as a gas barrier layer can be formed.

[0092] The water vapor permeability of the adhesive layer is preferably 20000 g / (m 2·day) or less, more preferably 10000g / (m 2 ·day) or less, more preferably 7000g / (m 2 ·day) or less, more preferably 5000g / (m 2 ·day) or less, particularly preferably 4800g / (m 2 ·day) or less, and most preferably 4500g / (m 2 ·day) or less. If it is within this range, the adhesive layer functions well as a gas barrier layer, forming a deformed portion with an excellent shape. If such an adhesive sheet is used, small adherends (for example, electronic components) can be peeled off with good precision. The smaller the water vapor permeability of the adhesive layer, the more preferable it is, and its lower limit is, for example, 100 g / (m 2 ·day).

[0093] The puncture strength of the adhesive layer is preferably 10mN to 3000mN, more preferably 30mN to 2500mN, further preferably 50mN to 2000mN, and particularly preferably 100mN to 2000mN. Within this range, the adhesive layer functions well as a gas barrier layer and satisfactorily undergoes shape changes due to gas generation, resulting in a deformed portion having a superior shape. Using such an adhesive sheet allows for precise peeling of small adherends (e.g., electronic components).

[0094] The ultraviolet transmittance of the pressure-sensitive adhesive layer at a wavelength of 360 nm is preferably 50% to 100%, more preferably 60% to 95%.

[0095] C-1. Pressure-sensitive adhesive B1

[0096] Examples of the pressure-sensitive adhesive B1 include acrylic adhesives, rubber adhesives, vinyl alkyl ether adhesives, silicone adhesives, polyester adhesives, polyamide adhesives, urethane adhesives, and styrene-diene block copolymer adhesives. Among these, acrylic adhesives and rubber adhesives are preferred, with acrylic adhesives being more preferred. As the adhesive B1 contained in the pressure-sensitive adhesive-containing adhesive layer, the adhesives described in Section B-2 can be used.

[0097] C-2. Curing Adhesive B2

[0098] Examples of the curable adhesive B2 include thermosetting adhesives and active energy ray-curable adhesives. An active energy ray-curable adhesive is preferably used. The adhesive layer formed by the active energy ray-curable adhesive is formed by irradiation with active energy rays, that is, it is an adhesive layer that has a predetermined adhesive strength after irradiation with active energy rays.

[0099] Examples of the resin material constituting the active energy ray-curable adhesive include those described in Ultraviolet Curing System (authored by Kiyoshi Kato, published by the General Technology Center (1989)), Photocuring Technology (edited by the Technical Information Association (2000)), Japanese Patent Application Publication No. 2003-292916, and Japanese Patent No. 4151850. More specifically, examples include a resin material (B2-1) containing a polymer serving as a masterbatch and an active energy ray-reactive compound (monomer or oligomer), and a resin material (B2-2) containing an active energy ray-reactive polymer.

[0100] Examples of the polymer serving as the masterbatch include rubber-based polymers such as natural rubber, polyisobutylene rubber, styrene-butadiene rubber, styrene-isoprene-styrene block copolymer rubber, reclaimed rubber, butyl rubber, polyisobutylene rubber, and nitrile rubber (NBR); silicone-based polymers; and acrylic polymers. These polymers may be used alone or in combination of two or more.

[0101] As the above-mentioned active energy ray reactive compound, for example, a photoreactive monomer or oligomer containing a functional group having a carbon-carbon multiple bond such as a plurality of acryloyl groups, methacryloyl groups, vinyl groups, allyl groups, ethynyl groups, etc. is mentioned. Among them, it is preferred to use a compound having an ethylenically unsaturated functional group, and more preferably to use a (meth) acrylic acid compound having an ethylenically unsaturated functional group. The compound having an ethylenically unsaturated functional group easily generates free radicals by ultraviolet light, so if the compound is used, an adhesive layer that can be cured in a short time can be formed. In addition, if a (meth) acrylic acid compound having an ethylenically unsaturated functional group is used, an adhesive layer having a moderate hardness after curing can be formed. Specific examples of photoreactive monomers or oligomers include (meth)acryloyl group-containing compounds such as trimethylolpropane tri(meth)acrylate, tetramethylolmethane tetra(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol monohydroxypenta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, polyethylene glycol di(meth)acrylate, and urethane (meth)acrylate compounds; and dimers to pentamers of such (meth)acryloyl group-containing compounds. These compounds can be used alone or in combination of two or more.

[0102] In addition, as the active energy ray-reactive compound, monomers such as epoxidized butadiene, glycidyl methacrylate, acrylamide, and vinylsiloxane, or oligomers thereof, can be used. The resin material (B2-1) containing these compounds can be cured by high-energy radiation such as ultraviolet rays and electron beams.

[0103] Furthermore, as the above-mentioned active energy ray reactive compound, a mixture of organic salts such as onium salts and compounds having multiple heterocycles in the molecule can be used. The mixture is irradiated by active energy rays (for example, ultraviolet rays, electron beams), and the organic salt is cracked to generate ions, which become starting species and trigger the ring-opening reaction of the heterocycle, thereby forming a three-dimensional network structure. As the above-mentioned organic salts, for example, iodonium salts, phosphonium salts, antimony salts, sulfonium salts, borates, etc. can be listed. As the heterocycle in the compound having multiple heterocycles in the above-mentioned molecule, oxirane, oxolane, thioethane, aziridine, etc. can be listed.

[0104] In the resin material (B2-1) containing the above-mentioned polymer serving as a masterbatch and an active energy ray-reactive compound, the content ratio of the active energy ray-reactive compound relative to 100 parts by weight of the polymer serving as a masterbatch is preferably 0.1 parts by weight to 500 parts by weight, more preferably 1 part by weight to 300 parts by weight, and further preferably 10 parts by weight to 200 parts by weight.

[0105] As the above-mentioned active energy ray reactive polymer, for example, there can be mentioned polymers containing active energy ray reactive functional groups having carbon-carbon multiple bonds such as acryloyl, methacryloyl, vinyl, allyl, and ethynyl. It is preferred to use a compound (polymer) having an ethylenically unsaturated functional group, and more preferably to use a (meth) acrylic polymer having an acryloyl or methacryloyl group. As specific examples of polymers having active energy ray reactive functional groups, there can be mentioned polymers composed of multifunctional (meth) acrylates. The polymer composed of multifunctional (meth) acrylates preferably has an alkyl ester having 4 or more carbon atoms in the side chain, more preferably an alkyl ester having 6 or more carbon atoms, further preferably an alkyl ester having 8 or more carbon atoms, particularly preferably an alkyl ester having 8 to 20 carbon atoms, and most preferably an alkyl ester having 8 to 18 carbon atoms.

[0106] The resin material (B2-2) containing the active energy ray-reactive polymer may further contain the active energy ray-reactive compound (monomer or oligomer).

[0107] The above-mentioned active energy ray curing adhesive can be cured by irradiation with active energy rays. In the adhesive sheet of the present invention, after the adherend is attached before the adhesive is cured, the adhesive is cured by irradiation with active energy rays, thereby making the adherend adhere. Examples of active energy rays include: gamma rays, ultraviolet rays, visible rays, infrared rays (heat rays), radio frequency waves, alpha rays, beta rays, electron beams, plasma streams, ionizing rays, particle rays, etc. The wavelength, irradiation amount, and other conditions of the active energy rays can be set to any appropriate conditions according to the type of resin material used, etc. For example, 10 to 1000 mJ / cm 2 The adhesive is cured by irradiating with ultraviolet rays.

[0108] D. Middle layer

[0109] Examples of the form of the intermediate layer include a resin layer and a layer having adhesive properties.

[0110] In one embodiment, the intermediate layer contains a thermoplastic resin. Such an intermediate layer may be a resin film containing a thermoplastic resin, a layer containing an adhesive C composed of a thermoplastic resin, or the like. In other embodiments, the intermediate layer contains a curable resin (e.g., a UV-curable resin or a thermosetting resin). Such an intermediate layer may be a resin film containing a curable resin, a layer containing a curable adhesive D, or the like.

[0111] The thickness of the intermediate layer is preferably 0.1 μm to 50 μm, more preferably 1 μm to 40 μm, and even more preferably 1.5 μm to 30 μm. Within these ranges, an intermediate layer that functions well as a gas barrier layer can be formed.

[0112] The water vapor permeability of the intermediate layer is preferably 5000 g / (m 2 ·day) or less, more preferably 4800g / (m 2 ·day) or less, more preferably 4500g / (m 2 ·day) or less, more preferably 4200g / (m 2 ·day) or less. If it is within this range, the intermediate layer functions well as a gas barrier layer, forming a deformed portion with an excellent shape. If such an adhesive sheet is used, small adherends (for example, electronic components) can be peeled off with good precision. The lower the water vapor permeability of the intermediate layer, the better, and its lower limit is, for example, 0.1g / (m 2 ·day).

[0113] The puncture strength of the intermediate layer is preferably 300mN to 5000mN, more preferably 500mN to 4500mN, and even more preferably 1000mN to 4000mN. Within this range, the intermediate layer functions well as a gas barrier layer and satisfactorily undergoes shape changes due to gas generation, resulting in a deformed portion with a superior shape. Using such a pressure-sensitive adhesive sheet allows for precise peeling of small adherends (e.g., electronic components).

[0114] The ultraviolet transmittance of the intermediate layer at a wavelength of 360 nm is preferably 50% to 100%, more preferably 60% to 95%.

[0115] D-1. Intermediate layer as resin layer

[0116] The intermediate layer serving as the resin layer is formed, for example, from a resin film. Examples of the resin forming the resin film include polyethylene terephthalate resins, polyolefin resins, styrene elastomer resins (e.g., SEBS), UV-curable resins, thermosetting resins, urethane resins, and epoxy resins. In one embodiment, the resin film is formed from a thermoplastic resin.

[0117] The thickness of the resin film is preferably 0.1 μm to 50 μm, more preferably 0.5 μm to 30 μm, and even more preferably 1 μm to 20 μm.

[0118] D-2. Intermediate layer as an adhesive layer

[0119] Examples of the intermediate layer as an adhesive layer include those containing pressure-sensitive adhesives and those containing curable adhesives. Preferably, the intermediate layer contains curable adhesive D. In particular, combining an adhesive layer containing pressure-sensitive adhesive A with an intermediate layer containing curable adhesive D as the adhesive layer yields an adhesive sheet capable of forming a more favorable deformable portion upon laser irradiation. Curable adhesive D can be any of the adhesives described in Section C-2.

[0120] The thickness of the intermediate layer as the adhesive layer is preferably 5 μm to 50 μm, more preferably 5 μm to 30 μm.

[0121] E. Method for manufacturing adhesive sheet

[0122] The adhesive sheet of the present invention can be manufactured by any appropriate method. Regarding the adhesive sheet of the present invention, for example, the following method can be cited: directly applying a gas generation layer forming composition containing adhesive A and an ultraviolet absorber on a predetermined substrate to form a gas generation layer, and applying an adhesive layer forming composition containing adhesive B on the gas generation layer to form an adhesive layer. In one embodiment, when the adhesive sheet has an intermediate layer, before forming the adhesive layer, the intermediate layer forming composition is applied to the gas generation layer to form an intermediate layer, and the adhesive layer forming composition is applied to the intermediate layer to form an adhesive layer. In addition, the adhesive sheet can also be formed by laminating after each layer is formed.

[0123] As a coating method for the above-mentioned composition, any appropriate coating method can be adopted. For example, each layer can be formed by drying after coating. As a coating method, for example, a coating method using a multi-layer coater (multi coater), a die coater, a gravure coater, an applicator, etc. can be mentioned. As a drying method, for example, natural drying, heat drying, etc. can be mentioned. The heating temperature in the case of heat drying can be set to any appropriate temperature according to the characteristics of the material to be dried. In addition, active energy ray irradiation (for example, ultraviolet irradiation) can be performed according to the form of each layer.

[0124] F. Processing methods of electronic components

[0125] The electronic component processing method of the present invention comprises: attaching the electronic component to the adhesive sheet; and irradiating the adhesive sheet with laser light to peel the electronic component from the adhesive sheet. Examples of the electronic component include semiconductor chips, LED chips, and MLCCs.

[0126] The electronic components can be peeled off at selected locations. Specifically, a plurality of electronic components can be attached and fixed to the pressure-sensitive adhesive sheet, and the electronic components can be peeled off in such a manner that some of the electronic components are peeled off while the other electronic components remain fixed.

[0127] In one embodiment, the electronic component processing method of the present invention includes performing a predetermined treatment on the electronic component after attaching the electronic component to an adhesive sheet and before removing the electronic component from the adhesive sheet. The treatment is not particularly limited and includes, for example, polishing, dicing, die bonding, wire bonding, etching, vapor deposition, molding, circuit formation, inspection, product testing, cleaning, transfer, alignment, repair, and device surface protection.

[0128] The size of the electronic component (the area of the attachment surface) is, for example, 1 μm. 2 ~250000μm 2 In one embodiment, the size of the electronic component (the area of the attachment surface) can be reduced to 1 μm.2 ~6400μm 2 In other embodiments, the size of the electronic component (the area of the attachment surface) can be 1 μm. 2 ~2500μm 2 electronic components for processing.

[0129] In one embodiment, a plurality of electronic components can be arranged on the adhesive sheet as described above. The spacing between the electronic components is, for example, 1 μm to 500 μm. This is advantageous in that the object to be processed can be temporarily fixed with a reduced spacing.

[0130] As the laser, for example, UV laser can be used. The irradiation power of the laser is, for example, 1 μJ to 1000 μJ. The wavelength of the UV laser is, for example, 240 nm to 380 nm.

[0131] In one embodiment, the method for handling an electronic component includes placing the electronic component on another sheet (eg, an adhesive sheet, a substrate, etc.) after peeling the electronic component.

[0132] Example

[0133] The present invention is described in detail below using examples, but the present invention is not limited to these examples. The evaluation methods in the examples are as follows. It should be noted that the following evaluations used adhesive sheets after the separator was removed. In the examples, "parts" and "%" are by weight unless otherwise specified.

[0134] (1) Transmittance

[0135] For PSA sheets with an intermediate layer, place the sheet in a spectrophotometer (trade name "UV-VIS Spectrophotometer SolidSpec 3700," manufactured by Shimadzu Corporation) with incident light perpendicular to the gas barrier layer side of the sample. The transmittance in the wavelength range of 300 nm to 800 nm is measured. The transmittance at 360 nm and 500 nm is extracted from the resulting transmission spectrum. For PSA sheets consisting solely of an PSA layer, the sheet is placed in the spectrophotometer with one release liner remaining. The release liner's own transmission spectrum is then measured and subtracted to obtain the transmission spectrum of the PSA layer itself. The transmittance at 360 nm and 500 nm is extracted from the resulting transmission spectrum.

[0136] (2) Maximum gas generation peak temperature

[0137] Approximately 0.5 mg of the adhesive sheet sample was placed in a furnace-type pyrolyzer, and the components volatilized by heating were analyzed by EGA-MS, which provides a mass spectrum. The temperature was raised from 40°C to 500°C at a rate of 10°C / minute using a furnace-type pyrolyzer (manufactured by Frontier Laboratories Ltd., trade name "PY2020iD"). The maximum gas generation peak temperature was calculated from the mass spectrum in the mass range of m / z = 10 to 800 using a GC / MS analyzer (manufactured by JEOL, trade name "JMS-T100GCV").

[0138] (3) Gasification starting temperature

[0139] The pressure-sensitive adhesive sheet was heated in the same manner as in (2) above, and the gas generation start temperature calculated by EGA analysis was defined as the gasification initiation temperature. The gas generation start temperature was defined as the temperature reaching the half-maximum value of the gas generation peak in the EGA / MS chromatogram obtained by EGA analysis.

[0140] (4) Type of gas generated

[0141] The PSA sheet sample was placed in an automatic sample combustion apparatus (manufactured by Mitsubishi Chemical Analytech Co., Ltd., trade name "AQF-2100H") and the generated gas was collected by heating at 400° C. for 30 minutes. The captured liquid was analyzed by ion chromatography to identify the type of generated gas.

[0142] (5) 5% weight loss temperature

[0143] The pressure-sensitive adhesive sheet was measured using a differential thermal analyzer (manufactured by TA Instruments, trade name "Discovery TGA") at a temperature increase of 10°C / min, an N2 atmosphere, and a flow rate of 25 ml / min at a temperature at which the weight of the sheet decreased by 5%.

[0144] (6) 10% weight loss temperature

[0145] The temperature at which the weight of the PSA sheet decreased by 10% was measured using a differential thermal analyzer (manufactured by TA Instruments, trade name "Discovery TGA") under the conditions of a temperature increase of 10°C / min, an N2 atmosphere, and a flow rate of 25 ml / min.

[0146] The 10% weight loss temperature was measured for each of the pressure-sensitive adhesive sheet and the gas-generating layer (UV absorber).

[0147] (7) Water vapor transmission rate

[0148] A sample was attached to cover the opening of an aluminum jig with a 10 mm x 10 mm opening to create a measurement sample. The sample was placed between the first and second chambers of a water vapor permeability tester (permatran-w3 / 34g, manufactured by MOCON) and evaluated using the MOCON method. The temperature and humidity conditions were 30°C / 90% RH, the gas (water vapor) flow rate was 10.0 ± 0.5 cc / min, and the measurement time was 20 hours.

[0149] The water vapor transmission rates of the adhesive sheet, adhesive layer, and intermediate layer were measured respectively.

[0150] (8) Surface shape changes

[0151] A measurement sample was prepared by laminating a glass plate (Matsunami Glass Co., Ltd., large glass slide S9112 (standard large white-edge polished No. 2)) to the gas-generating layer side of the adhesive sheet (the side opposite the adhesive layer). A UV laser with a wavelength of 355 nm and a beam diameter of approximately 20 μm was pulsed at 0.80 mW and a frequency of 40 kHz from the glass plate side of the measurement sample to generate gas from the gas-generating layer. The adhesive layer surface corresponding to any pulsed point (the gas-generating layer surface in Example 1 and Comparative Example 1) was observed using a confocal laser microscope 24 hours after laser irradiation, and the vertical displacement Y and horizontal displacement X (diameter; full width at half maximum) were measured.

[0152] When the displacement Y is 8 μm or more, the peeling property is significantly excellent (◎ in the table); when the displacement Y is 0.6 μm or more and less than 8 μm, the peeling property is good (○ in the table); when the displacement Y is less than 0.6 μm, the peeling property is insufficient (× in the table).

[0153] (9) Haze value

[0154] For PSA sheets with an intermediate layer, the release liner is removed and the sample is placed in a haze meter so that incident light is perpendicular to the sample to measure the haze value. For PSA sheets consisting solely of an adhesive layer, the haze value is measured with one release liner remaining. The haze value of the release liner itself is then measured and subtracted to obtain the haze value of the adhesive layer itself.

[0155] When the haze value was 20% or less, the adherend visual recognition was evaluated as good (in the table, ∘); when the haze value was 20% or more and 50% or less, the adherend visual recognition was evaluated as acceptable (in the table, △); when the haze value was 50% or more, the adherend visual recognition was evaluated as poor (in the table, ×).

[0156] (10) Adhesion (gas generation layer side)

[0157] A measurement sample was prepared by laminating PET#25 to the adhesive layer side of the PSA sheet. The adhesive strength of the gas-generating layer side of the measurement sample to SUS430 was measured according to JIS Z 0237:2000 (lamination conditions: 1 reciprocating motion of a 2 kg roller, tensile speed: 300 mm / min, peel angle: 180°).

[0158] (11) Adhesion (adhesive layer)

[0159] A measurement sample was prepared by laminating PET#25 to the gas-generating layer side of the PSA sheet. The adhesive strength of the PSA layer side of the measurement sample to SUS430 was measured according to JIS Z 0237:2000 (lamination conditions: 1 round trip of a 2 kg roller, tensile speed: 300 mm / min, peel angle: 180°).

[0160] (12) In-plane uniformity of deformation

[0161] As shown in the above (8), the gas generation layer is irradiated with UV laser light.

[0162] Microscopic observation of randomly selected deformed areas of a 2 mm x 2 mm area indicated good (◯ in the table), acceptable (△ in the table), and poor (× in the table) when 90% or more of the convex areas were identical. Identical dimensions refer to a difference in displacement X of within ±20%.

[0163] (13) Positional selectivity of deformation

[0164] The gas generation layer is irradiated with UV laser light as described in (8) above.

[0165] The case where only a single deformation occurred in the laser irradiation part was rated as acceptable (◯), and the case where multiple deformations also occurred around the laser irradiation part was rated as unacceptable (×).

[0166] (14) Elastic modulus

[0167] The elastic modulus was measured using a nanoindenter (Triboindenter TI-950 manufactured by Hysitron Inc.) by a single indentation method at a predetermined temperature (25°C) with an indentation speed of approximately 500 nm / sec, a withdrawal speed of approximately 500 nm / sec, and an indentation depth of approximately 1500 nm.

[0168] [Manufacturing Example 1] Preparation of Composition a for Forming a Gas Generation Layer

[0169] 30 parts by weight of 2-ethylhexyl acrylate, 70 parts by weight of ethyl acrylate, 4 parts by weight of 2-hydroxyethyl acrylate, 5 parts by weight of methyl methacrylate, and 0.2 parts by weight of benzoyl peroxide as a polymerization initiator were added to toluene, and then heated to 70° C. to obtain a toluene solution of an acrylic copolymer (polymer A).

[0170] A toluene solution of polymer A (polymer A: 100 parts by weight), 1.5 parts by weight of an isocyanate crosslinker (trade name "Coronate L" manufactured by Nippon Polyurethane Co., Ltd.), and 20 parts by weight of a UV absorber (trade name "Tinuvin 477" manufactured by BASF, structure: [Chemical 1]) were mixed to prepare a gas generation layer-forming composition a. The composition of the gas generation layer-forming composition a is shown in Table 1.

[0171] [Chemistry 1]

[0172]

[0173] [Production Example 2] Preparation of Composition b for Forming a Gas Generation Layer

[0174] A composition b for forming a gas generation layer was prepared in the same manner as in Production Example 1, except that the amount of the UV absorber added was 10 parts by weight.

[0175] [Production Example 3] Preparation of Composition c for Forming a Gas Generation Layer

[0176] A gas generation layer-forming composition c was prepared in the same manner as in Production Example 1, except that 10 parts by weight of 2,4-bis(2-hydroxy-4-butoxyphenyl)-6-(2,4-dibutoxyphenyl)-1,3,5-triazine (trade name "TINUVIN 460", manufactured by BASF, structure: [Chemical 2]) was used as a UV absorber. The composition of the gas generation layer-forming composition c is shown in Table 1.

[0177] [Chemistry 2]

[0178]

[0179] [Production Example 4] Preparation of Composition d for Forming a Gas Generation Layer

[0180] A gas generation layer-forming composition d was prepared in the same manner as in Production Example 1, except that 20 parts by weight of a reaction product of 2-(4,6-bis(2,4-dimethylphenyl)-1,3,5-triazin-2-yl)-5-hydroxyphenyl and [(C10-C16 (mainly C12-C13)alkoxy)methyl]oxirane (trade name "TINUVIN 400," manufactured by BASF, structure: [Chemical 3]) was used as a UV absorber. The composition of the gas generation layer-forming composition d is shown in Table 1.

[0181] [Chemistry 3]

[0182]

[0183] [Production Example 5] Preparation of Composition e for Forming Gas Generation Layer

[0184] 30 parts by weight of 2-ethylhexyl acrylate, 70 parts by weight of methyl acrylate, 10 parts by weight of acrylic acid, and 0.2 parts by weight of benzoyl peroxide as a polymerization initiator were added to ethyl acetate, and then heated to 70° C. to obtain an ethyl acetate solution of an acrylic copolymer (polymer B).

[0185] A gas generation layer-forming composition e was prepared by mixing an ethyl acetate solution of polymer B (polymer B: 100 parts by weight), 1 part by weight of an isocyanate crosslinking agent (trade name "Coronate L" manufactured by Nippon Polyurethane Co., Ltd.), and 20 parts by weight of a UV absorber (trade name "Tinuvin 477" manufactured by BASF). The composition of the gas generation layer-forming composition e is shown in Table 1.

[0186] [Manufacturing Example 6] Preparation of Composition f for Forming Gas Generation Layer

[0187] 95 parts by weight of 2-ethylhexyl acrylate, 5 parts by weight of acrylic acid, and 0.15 parts by weight of benzoyl peroxide as a polymerization initiator were added to ethyl acetate, and then heated to 70° C. to obtain an ethyl acetate solution of an acrylic copolymer (polymer C).

[0188] A gas generation layer-forming composition f was prepared by mixing an ethyl acetate solution of polymer C (polymer C: 100 parts by weight), 1 part by weight of an isocyanate crosslinking agent (trade name "Coronate L" manufactured by Nippon Polyurethane Co., Ltd.), and 20 parts by weight of a UV absorber (trade name "Tinuvin 477" manufactured by BASF). The composition of gas generation layer-forming composition g is shown in Table 1.

[0189] [Manufacturing Example 7] Preparation of Composition g for Forming a Gas Generation Layer

[0190] 95 parts by weight of 2-ethylhexyl acrylate, 5 parts by weight of acrylic acid, and 0.15 parts by weight of benzoyl peroxide as a polymerization initiator were added to ethyl acetate, and then heated to 70° C. to obtain an ethyl acetate solution of an acrylic copolymer (polymer C).

[0191] A gas generation layer-forming composition g was prepared by mixing an ethyl acetate solution of polymer C (polymer C: 100 parts by weight), 0.1 parts by weight of an epoxy crosslinking agent (trade name "TETRAD-C" manufactured by Mitsubishi Gas Chemical Co., Ltd.), and 20 parts by weight of a UV absorber (trade name "Tinuvin 477" manufactured by BASF). The composition of gas generation layer-forming composition g is shown in Table 3.

[0192] [Manufacturing Example 8] Preparation of Composition h for Forming a Gas Generation Layer

[0193] Gas generation layer-forming composition h was prepared by mixing 100 parts by weight of a maleic acid-modified styrene-ethylene-butylene-styrene block copolymer (SEBS: styrene moiety / ethylene-butylene moiety (weight ratio) = 30 / 70, acid value: 10 (mg-CH₃ONa / g), manufactured by Asahi Kasei Chemicals Corporation, trade name "Tuftec M1913"), 3 parts by weight of an epoxy crosslinking agent (manufactured by Mitsubishi Gas Chemical Co., Ltd., trade name "TETRAD-C"), 20 parts by weight of a UV absorber (manufactured by BASF, trade name "Tinuvin 477"), and toluene as a solvent. The composition of gas generation layer-forming composition h is shown in Table 3.

[0194] [Production Example 8'] Preparation of Composition i for Forming Gas Generation Layer

[0195] 100 parts by weight of butyl acrylate, 5 parts by weight of acrylic acid, and 0.2 parts by weight of benzoyl peroxide as a polymerization initiator were added to toluene, and then heated to 70° C. to obtain a toluene solution of an acrylic copolymer (polymer D).

[0196] A toluene solution of polymer D (polymer D: 100 parts by weight), 0.1 parts by weight of an epoxy crosslinking agent (trade name "TETRAD-C" manufactured by Mitsubishi Gas Chemical Co., Ltd.), and 20 parts by weight of a UV absorber (trade name "Tinuvin 400" manufactured by BASF) were mixed to prepare a gas generation layer-forming composition i. The composition of the gas generation layer-forming composition i is shown in Table 3.

[0197] [Production Example 8] Preparation of Composition J for Forming Gas Generation Layer

[0198] In the same manner as in Production Example 5, an ethyl acetate solution of an acrylic acid-based copolymer (polymer B) was obtained.

[0199] A gas generation layer-forming composition e was prepared by mixing a polymer B ethyl acetate solution (polymer B: 100 parts by weight), 1 part by weight of an epoxy crosslinking agent (trade name "Coronate L" manufactured by Nippon Polyurethane Co., Ltd.), and 20 parts by weight of a UV absorber (trade name "Tinuvin 477" manufactured by BASF). The composition of the gas generation layer-forming composition e is shown in Table 1.

[0200] A gas generation layer-forming composition i was prepared by mixing an ethyl acetate solution of polymer B (polymer B: 100 parts by weight), 0.1 parts by weight of an epoxy crosslinking agent (trade name "TETRAD-C" manufactured by Mitsubishi Gas Chemical Co., Ltd.), and 20 parts by weight of a UV absorber (trade name "Tinuvin 400" manufactured by BASF). The composition of gas generation layer-forming composition j is shown in Table 3.

[0201] [Production Example 8'] Preparation of Composition K for Forming a Gas Generation Layer

[0202] After adding 50 parts by weight of butyl acrylate, 50 parts by weight of ethyl acrylate, 5 parts by weight of acrylic acid, 0.1 parts by weight of 2-hydroxyethyl acrylate, 0.3 parts by weight of trimethylolpropane triacrylate and 0.1 parts by weight of benzoyl peroxide as a polymerization initiator to toluene, the mixture was heated to 70° C. to obtain a toluene solution of an acrylic copolymer (polymer E).

[0203] A toluene solution of polymer E (polymer E: 100 parts by weight), 0.1 parts by weight of an epoxy crosslinking agent (trade name "TETRAD-C" manufactured by Mitsubishi Gas Chemical Co., Ltd.), and 20 parts by weight of a UV absorber (trade name "Tinuvin 400" manufactured by BASF) were mixed to prepare a gas generation layer-forming composition i. The composition of gas generation layer-forming composition k is shown in Table 3.

[0204] [Manufacturing Example 9] Preparation of Composition I for Forming Gas Generation Layer

[0205] A gas generation layer-forming composition e was prepared in the same manner as in Production Example 1, except that 20 parts by weight of 2-[5-chloro-2H-benzotriazol-2-yl]-4-methyl-6-(tert-butyl)phenol (trade name "TINUVIN 326", manufactured by BASF) was used as a UV absorber. The composition of the gas generation layer-forming composition I is shown in Table 1.

[0206] [Manufacturing Example 10] Preparation of Composition II Containing Heat-Expandable Microspheres

[0207] Without mixing ultraviolet light absorber, the mixing amount of cross-linking agent was made into 1.4 weight parts, and 30 weight parts of heat-expandable microspheres (manufactured by Matsumoto Oil and Fats Pharmaceutical Co., Ltd., trade name "Matsumoto Microsphere F-50D") and 10 weight parts of terpene-phenol tackifying resins (manufactured by Sumitomo Bakelite Co., Ltd., trade name "Sumilite resin PR51732") were mixed. Otherwise, the same operation as in Manufacturing Example 5 was carried out to prepare a composition II containing heat-expandable microspheres.

[0208] [Manufacturing Example 11] Preparation of Composition III Containing Heat-Expandable Microspheres

[0209] A composition III containing heat-expandable microspheres was prepared in the same manner as in Production Example 8, except that 20 parts by weight of a terpene-phenol tackifying resin (manufactured by Sumitomo Bakelite Co., Ltd., trade name "Sumilite resin PR51732") was used instead of 10 parts by weight of a terpene-phenol tackifying resin (manufactured by Yasuhara Chemical Co., Ltd., trade name "YS polyster T160").

[0210] [Table 1]

[0211]

[0212] [Manufacturing Example 12] Preparation of Adhesive a

[0213] In the same manner as in Production Example 1, a toluene solution of an acrylic copolymer (polymer A) was obtained.

[0214] Adhesive a was prepared by mixing a toluene solution of polymer A (polymer A: 100 parts by weight), 3 parts by weight of an isocyanate crosslinking agent (trade name "Coronate L" manufactured by Nippon Polyurethane Co., Ltd.), and 5 parts by weight of a surfactant (trade name "EXCEPARL IPP" manufactured by Kao Corporation). The composition of Adhesive a is shown in Table 2.

[0215] [Manufacturing Example 12'] Preparation of Adhesive b

[0216] In the same manner as in Production Example 6, a toluene solution of an acrylic copolymer (polymer C) was obtained.

[0217] Adhesive b was prepared by mixing a toluene solution of polymer C (polymer C: 100 parts by weight), 3 parts by weight of an isocyanate crosslinking agent (trade name "Coronate L" manufactured by Nippon Polyurethane Co., Ltd.), and 1 part by weight of an epoxy crosslinking agent (trade name "TETRAD-C" manufactured by Mitsubishi Gas Chemical Co., Ltd.). The composition of adhesive b is shown in Table 2.

[0218] [Manufacturing Example 13] Preparation of Adhesive I

[0219] Adhesive I was prepared in the same manner as in Production Example 10 except that the amount of the crosslinking agent added was 1 part by weight and no surfactant was contained. The composition of Adhesive I is shown in Table 2.

[0220] [Table 2]

[0221]

[0222] [Manufacturing Example 14] Preparation of Intermediate Layer Forming Composition a

[0223] In the same manner as in Production Example 5, an ethyl acetate solution of an acrylic acid-based copolymer (polymer B) was obtained.

[0224] An ethyl acetate solution of polymer B (polymer B: 100 parts by weight), 1 part by weight of an epoxy crosslinking agent (trade name "TETRAD C" manufactured by Mitsubishi Gas Chemical Co., Ltd.), 50 parts by weight of a UV oligomer (trade name "Ziguang UV-1700B" manufactured by Mitsubishi Chemical Corporation), and 3 parts by weight of a photopolymerization initiator (trade name "Omnirad 127" manufactured by BASF) were mixed to prepare an intermediate layer-forming composition a. The composition of the intermediate layer-forming composition a is shown in Table 3.

[0225] [Manufacturing Example 15] Preparation of composition b for forming an intermediate layer

[0226] An intermediate layer-forming composition b was prepared by mixing 100 parts by weight of a maleic acid-modified styrene-ethylene-butylene-styrene block copolymer (SEBS: styrene moiety / ethylene-butylene moiety (weight ratio) = 30 / 70, acid value: 10 (mg-CH₃ONa / g), manufactured by Asahi Kasei Chemicals Corporation, trade name "Tuftec M1913"), 3 parts by weight of an epoxy crosslinking agent (manufactured by Mitsubishi Gas Chemical Co., Ltd., trade name "TETRAD-C"), 3 parts by weight of a fatty acid ester surfactant (manufactured by Kao Corporation, trade name "EXCEPARL IPP", molecular weight: 298.5, alkyl group carbon number: 16), and toluene as a solvent. The composition of the intermediate layer-forming composition b is shown in Table 3.

[0227] [Table 3]

[0228]

[0229] [Example 1]

[0230] The gas generation layer forming composition a obtained in Manufacturing Example 1 was applied to a polyethylene terephthalate film (manufactured by Toray Industries, Ltd., trade name "Cerapeel", thickness: 38 μm) with a silicone release agent-treated surface so that the thickness after solvent volatilization (drying) was 7 μm. Thereafter, the film was dried to obtain an adhesive sheet containing only the gas generation layer on the polyethylene terephthalate film.

[0231] The obtained PSA sheet was subjected to the above-mentioned evaluations (1) to (13). The results are shown in Table 4.

[0232] [Example 2]

[0233] The adhesive a obtained in Manufacturing Example 10 was applied to a polyethylene terephthalate film (thickness: 75 μm) with a silicone release agent-treated surface so that the thickness after solvent evaporation (drying) was 15 μm, and then dried to form an adhesive layer precursor layer a on the polyethylene terephthalate film.

[0234] The gas generation layer forming composition a obtained in Manufacturing Example 1 is applied to a polyethylene terephthalate film (manufactured by Toray Industries, Ltd., trade name "Cerapeel", thickness: 38 μm) with a silicone release agent-treated surface so that the thickness after solvent evaporation (drying) is 7 μm. Thereafter, the composition is dried to form a gas generation layer precursor layer a on the polyethylene terephthalate film.

[0235] The PSA layer precursor layer a and the gas generation layer precursor layer a were laminated and bonded between rolls to obtain a PSA sheet (PSA layer / gas generation layer) sandwiched between a polyethylene terephthalate film having a silicone release agent-treated surface.

[0236] The obtained PSA sheet was subjected to the above-mentioned evaluations (1) to (13). The results are shown in Table 4.

[0237] [Example 3]

[0238] The adhesive a obtained in Manufacturing Example 10 was applied to a polyethylene terephthalate film (thickness: 75 μm) with a silicone release agent-treated surface so that the thickness after solvent evaporation (drying) was 15 μm, and then dried to form an adhesive layer precursor layer a on the polyethylene terephthalate film.

[0239] The intermediate layer forming composition a obtained in Manufacturing Example 12 is applied to a polyethylene terephthalate film (manufactured by Toray Industries, Ltd., trade name "Cerapeel", thickness: 38 μm) with a silicone release agent-treated surface so that the thickness after solvent evaporation (drying) is 15 μm, and then dried to form an intermediate layer precursor layer a on the polyethylene terephthalate film.

[0240] Next, the adhesive layer precursor layer a and the intermediate layer precursor layer a were laminated between rolls and bonded together. The intermediate layer precursor layer was heated at 500 mJ / cm 2 UV irradiation was performed under conditions of to obtain a laminate precursor layer a sandwiched between polyethylene terephthalate films with silicone release agent-treated surfaces.

[0241] The gas generation layer forming composition a obtained in Manufacturing Example 1 is applied to a polyethylene terephthalate film (manufactured by Toray Industries, Ltd., trade name "Cerapeel", thickness: 38 μm) with a silicone release agent-treated surface so that the thickness after solvent evaporation (drying) is 7 μm. Thereafter, the composition is dried to form a gas generation layer precursor layer a on the polyethylene terephthalate film.

[0242] After peeling off the polyethylene terephthalate film with the silicone release agent treated surface on the intermediate layer precursor layer a side of the above-mentioned laminate precursor layer a, the intermediate layer precursor layer a of the laminate precursor layer a and the above-mentioned gas generation layer precursor layer a are laminated and bonded between rollers to obtain an adhesive sheet (adhesive layer / intermediate layer / gas generation layer) clamped by the polyethylene terephthalate film with the silicone release agent treated surface.

[0243] The obtained PSA sheet was subjected to the above-mentioned evaluations (1) to (13). The results are shown in Table 4.

[0244] [Example 4]

[0245] The adhesive a obtained in Manufacturing Example 10 was applied to a polyethylene terephthalate film (thickness: 75 μm) with a silicone release agent-treated surface so that the thickness after solvent evaporation (drying) was 15 μm, and then dried to form an adhesive layer precursor layer a on the polyethylene terephthalate film.

[0246] The intermediate layer forming composition b obtained in Manufacturing Example 13 is applied to a polyethylene terephthalate film (manufactured by Toray Industries, Ltd., trade name "Cerapeel", thickness: 38 μm) with a silicone release agent-treated surface so that the thickness after solvent evaporation (drying) is 15 μm, and then dried to form an intermediate layer precursor layer a on the polyethylene terephthalate film.

[0247] Next, the adhesive layer precursor layer a and the intermediate layer precursor layer b were laminated and bonded between rolls to obtain a laminate precursor layer b sandwiched between the polyethylene terephthalate film having a silicone release agent-treated surface.

[0248] The gas generation layer forming composition a obtained in Manufacturing Example 1 is applied to a polyethylene terephthalate film (manufactured by Toray Industries, Ltd., trade name "Cerapeel", thickness: 38 μm) with a silicone release agent-treated surface so that the thickness after solvent evaporation (drying) is 7 μm. Thereafter, the composition is dried to form a gas generation layer precursor layer a on the polyethylene terephthalate film.

[0249] After peeling off the polyethylene terephthalate film with a silicone release agent-treated surface on the intermediate layer precursor layer b side of the above-mentioned laminate precursor layer b, the intermediate layer precursor layer b of the laminate precursor layer b and the above-mentioned gas generation layer precursor layer a are laminated and bonded between rollers to obtain an adhesive sheet (adhesive layer / intermediate layer / gas generation layer) clamped by the polyethylene terephthalate film with a silicone release agent-treated surface.

[0250] The obtained PSA sheet was subjected to the above-mentioned evaluations (1) to (13). The results are shown in Table 4.

[0251] [Example 5]

[0252] The adhesive a obtained in Manufacturing Example 10 was applied to a polyethylene terephthalate film (thickness: 75 μm) with a silicone release agent-treated surface so that the thickness after solvent evaporation (drying) was 15 μm, and then dried to form an adhesive layer precursor layer a on the polyethylene terephthalate film.

[0253] The gas generation layer forming composition a obtained in Manufacturing Example 1 is applied to a polyethylene terephthalate film (manufactured by Toray Industries, Ltd., trade name "Cerapeel", thickness: 38 μm) with a silicone release agent-treated surface so that the thickness after solvent evaporation (drying) is 7 μm. Thereafter, the composition is dried to form a gas generation layer precursor layer a on the polyethylene terephthalate film.

[0254] The pressure-sensitive adhesive layer precursor layer a was laminated between rolls and attached to one side of a polyethylene terephthalate film (manufactured by Toray Industries, Ltd., trade name "Lumirror #2F51N," thickness: 2 μm).

[0255] Next, the gas generation layer precursor layer a was laminated between rolls and bonded to the side of the polyethylene terephthalate film opposite to the adhesive layer precursor layer a.

[0256] In this manner, a pressure-sensitive adhesive sheet (pressure-sensitive adhesive layer / intermediate layer / gas generation layer) sandwiched between the polyethylene terephthalate film having the silicone release agent-treated surface was obtained.

[0257] The obtained PSA sheet was subjected to the above-mentioned evaluations (1) to (13). The results are shown in Table 4.

[0258] [Example 6]

[0259] A pressure-sensitive adhesive sheet was obtained in the same manner as in Example 5 except that the gas generation layer-forming composition b was used instead of the gas generation layer-forming composition a. The obtained pressure-sensitive adhesive sheet was subjected to the above-mentioned evaluations (1) to (13). The results are shown in Table 5.

[0260] [Example 7]

[0261] A pressure-sensitive adhesive sheet was obtained in the same manner as in Example 5 except that the gas generation layer-forming composition c was used instead of the gas generation layer-forming composition a. The obtained pressure-sensitive adhesive sheet was subjected to the above-mentioned evaluations (1) to (13). The results are shown in Table 5.

[0262] [Example 8]

[0263] A pressure-sensitive adhesive sheet was obtained in the same manner as in Example 5 except that the gas generation layer-forming composition d was used instead of the gas generation layer-forming composition a. The obtained pressure-sensitive adhesive sheet was subjected to the above-mentioned evaluations (1) to (13). The results are shown in Table 5.

[0264] [Example 9]

[0265] A pressure-sensitive adhesive sheet was obtained in the same manner as in Example 5 except that the gas generation layer-forming composition a was replaced with the gas generation layer-forming composition e. The obtained pressure-sensitive adhesive sheet was subjected to the above-mentioned evaluations (1) to (13). The results are shown in Table 5.

[0266] [Example 10]

[0267] A pressure-sensitive adhesive sheet was obtained in the same manner as in Example 5 except that the gas generation layer-forming composition f was used instead of the gas generation layer-forming composition a. The obtained pressure-sensitive adhesive sheet was subjected to the above-mentioned evaluations (1) to (13). The results are shown in Table 5.

[0268] [Example 11]

[0269] A pressure-sensitive adhesive sheet was obtained in the same manner as in Example 1 except that the gas generation layer-forming composition g was used instead of the gas generation layer-forming composition a. The obtained pressure-sensitive adhesive sheet was subjected to the above-mentioned evaluation. The results are shown in Table 6.

[0270] [Example 12]

[0271] A pressure-sensitive adhesive sheet was obtained in the same manner as in Example 1 except that the gas generation layer-forming composition h was used instead of the gas generation layer-forming composition a. The obtained pressure-sensitive adhesive sheet was subjected to the above-mentioned evaluation. The results are shown in Table 6.

[0272] [Table 4]

[0273]

[0274] [Table 5]

[0275]

[0276] [Table 6]

[0277]

[0278] [Comparative Example 1]

[0279] A pressure-sensitive adhesive sheet was obtained in the same manner as in Example 1 except that the gas generation layer-forming composition a was replaced with the gas generation layer-forming composition I. The obtained pressure-sensitive adhesive sheet was subjected to the above-mentioned evaluations (1) to (13). The results are shown in Table 7.

[0280] [Comparative Example 2]

[0281] A pressure-sensitive adhesive sheet was obtained in the same manner as in Example 5 except that the gas generation layer-forming composition a was replaced with the gas generation layer-forming composition I. The obtained pressure-sensitive adhesive sheet was subjected to the above-mentioned evaluations (1) to (13). The results are shown in Table 7.

[0282] [Comparative Example 3]

[0283] An adhesive sheet was obtained by the same procedure as in Example 5 except that adhesive I was used instead of adhesive a, the thickness of the adhesive layer was set to 10 μm, a 188 μm thick PET film was used as the intermediate layer, and a 48 μm thick gas generation layer was formed using composition II containing heat-expandable microspheres instead of composition a for forming a gas generation layer. The obtained adhesive sheet was subjected to the above-mentioned evaluations (1) to (13). The results are shown in Table 7.

[0284] [Comparative Example 4]

[0285] An adhesive sheet was obtained in the same manner as in Example 5 except that adhesive I was used instead of adhesive a, the thickness of the adhesive layer was set to 10 μm, a 100 μm thick PET film was used as the intermediate layer, and a 48 μm thick gas generation layer was formed using composition III containing heat-expandable microspheres instead of composition a for forming a gas generation layer. The obtained adhesive sheet was subjected to the above-mentioned evaluations (1) to (13). The results are shown in Table 7.

[0286] [Table 7]

[0287]

[0288] Description of Reference Numerals

[0289] 10 Gas Generation Layer

[0290] 20 Adhesive layer

[0291] 30 middle layer

[0292] 100, 100', 200 adhesive sheets

Claims

1. A pressure-sensitive adhesive sheet comprising a gas-generating layer that generates gas upon laser irradiation, wherein the gas-generating layer contains a triazine-based ultraviolet absorber. The haze value is 50% or less.

2. The adhesive sheet according to claim 1, wherein The thickness of the gas generation layer is 0.1 μm to 50 μm.

3. The adhesive sheet according to claim 1 or 2, wherein The gas generation layer is a layer capable of absorbing ultraviolet rays.

4. The adhesive sheet according to claim 1 or 2, wherein The transmittance of ultraviolet rays with a wavelength of 360nm is 30% or less.

5. The adhesive sheet according to claim 1 or 2, wherein The transmittance of ultraviolet rays with a wavelength of 500nm is 50% to 100%.

6. The adhesive sheet according to claim 1 or 2, wherein The gas generating layer is a layer that generates hydrocarbon-based gas.

7. The adhesive sheet according to claim 1 or 2, wherein The gasification starting temperature of the gas generation layer is 150°C to 500°C.

8. The adhesive sheet according to claim 1 or 2, wherein The temperature for 10% weight loss is 200°C to 500°C.

9. The adhesive sheet according to claim 1 or 2, wherein An adhesive layer is further provided on at least one side of the gas generation layer. The adhesive layer is a layer whose surface is deformed by irradiating the adhesive sheet with laser light.

10. The adhesive sheet according to claim 9, wherein The thickness of the adhesive layer is 0.1 μm to 50 μm.

11. The adhesive sheet according to claim 9, wherein The adhesive layer is foamed by irradiating the adhesive sheet with laser light.

12. A method for processing an electronic component, comprising: an electronic component is attached to the adhesive sheet according to any one of claims 1 to 11; and the adhesive sheet is irradiated with laser light to peel the electronic component from the adhesive sheet.

13. The method for processing electronic components according to claim 12, wherein: The electronic components are peeled off at selected locations.

14. The method for processing electronic components according to claim 12 or 13, comprising: After the electronic component is attached to the adhesive sheet and before the electronic component is peeled off from the adhesive sheet, The electronic component is subjected to prescribed treatment.

15. The method for processing electronic components according to claim 14, wherein: The processing is grinding, dicing, chip bonding, wire bonding, etching, evaporation, molding, circuit formation, inspection, product testing, cleaning, transfer, alignment, repair, or protection of the device surface.

16. The method for processing electronic components according to claim 12 or 13, comprising: After the electronic component is peeled off from the pressure-sensitive adhesive sheet, the electronic component is placed on another sheet.

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