Adhesive sheet for temporary fixing of electronic components

Abstract

To provide an adhesive sheet for temporarily fixing electronic components, capable of exhibiting good detachability under the influence of photothermal conversion effect, while having excellent visible light permeability.SOLUTION: The adhesive sheet for temporarily fixing electronic components of the present invention comprises a laminate structure A including a substrate and a gas generation layer disposed on at least one side of the substrate and an adhesive layer disposed on at least one side of the laminate structure A, and has a transmittance of light with a wavelength of 1032 nm of 75% or less and a transmittance of light with a wavelength of 600 nm of 50% or more.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a pressure-sensitive adhesive sheet for temporarily fixing electronic components. [Background technology]

[0002] In recent years, to improve the performance of semiconductor devices, there has been an accelerating trend, particularly in areas such as semiconductor packaging, to fix semiconductor chips and encapsulated resin substrates to rigid support substrates and perform high-temperature processes. For example, in processes such as the RDL formation process for forming circuits on semiconductor packages encapsulated with black resin, a method has been investigated in which the workpiece is temporarily fixed flatly to a light-transmitting substrate such as glass, and then the rigid substrate is separated after the RDL formation on the workpiece. For such applications, liquid adhesives containing carbon black powder are widely used as photothermal conversion materials. In technologies using photothermal conversion materials, the photothermal conversion material is applied to a light-transmitting substrate to form a photothermal conversion layer. During processing, the workpiece is firmly fixed. During peeling, the photothermal conversion layer absorbs light and converts it into heat, resulting in thermal decomposition, allowing for easy separation of the workpiece and the light-transmitting substrate. However, many of these liquid adhesives used as photothermal conversion materials contain carbon black powder or fillers, which can lead to sedimentation of the dispersion over time, making material management difficult during manufacturing. To solve these problems, a technology has been investigated that uses a general-purpose black printed substrate made from a film of a material containing carbon black to create double-sided tape. However, the black printed layer has poor heat and chemical resistance, making it unsuitable for semiconductor applications. Furthermore, when materials containing carbon black absorb IR lasers (e.g., wavelength: 1032 nm), they also absorb visible light (e.g., wavelength: 600 nm). This reduces visibility through the tape, making it impossible to confirm the position or perform lot tracing of different semiconductor chips embedded in the black resin. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 4565804 [Patent Document 2] Patent No. 4405246 Summary of the Invention [Problem to be solved by the invention]

[0004] The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide an adhesive sheet for temporarily fixing electronic components that has excellent visible light transmittance and can also exhibit good releasability due to the influence of photothermal conversion action. [Means for solving the problem]

[0005] The pressure-sensitive adhesive sheet for temporarily fixing electronic components of the present invention comprises a substrate, a laminate structure A including a gas-generating layer arranged on at least one side of the substrate, and a pressure-sensitive adhesive layer arranged on at least one side of the laminate structure A, and has a transmittance of 75% or less for light with a wavelength of 1032 nm and a transmittance of 50% or more for light with a wavelength of 600 nm. In one embodiment, the gas generating layer is a layer capable of absorbing near-infrared rays. In one embodiment, the gas generating layer comprises a near infrared absorbing agent. In one embodiment, the near-infrared absorbing agent is a substance containing elemental tungsten. In one embodiment, the near-infrared absorbing agent is a substance containing elemental cesium. In one embodiment, the gas generation layer has a modulus of elasticity measured by nanoindentation method of 100 MPa or more. In one embodiment, the substrate is made of a polyimide-based resin, a polyester-based resin, or a polyether ether ketone-based resin. According to another aspect of the present invention, there is provided a method for treating electronic components, which comprises placing an electronic component on the pressure-sensitive adhesive sheet and then subjecting the electronic component to a predetermined treatment. In one embodiment, the treatment is grinding, dicing, die bonding, wire bonding, etching, vapor deposition, chemical cleaning, molding, rewiring layer formation, through-hole formation, or device surface protection. According to yet another aspect of the present invention, there is provided a method for separating a temporarily fixed electronic component from a support, which comprises placing the pressure-sensitive adhesive sheet for temporarily fixing an electronic component on a support, placing an electronic component on the pressure-sensitive adhesive sheet for temporarily fixing an electronic component, and then irradiating the pressure-sensitive adhesive sheet with light to separate the base material from the gas-generating layer. In one embodiment, the light is laser light. In one embodiment, the wavelength of the laser light is 800 nm or longer. In one embodiment, the wavelength of the laser light is 380 nm or less. [Effects of the Invention]

[0006] According to the present invention, it is possible to provide a pressure-sensitive adhesive sheet for temporary fixing of electronic components that has excellent visible light transmittance and is also capable of exhibiting good releasability due to the influence of photothermal conversion action. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a schematic cross-sectional view of a pressure-sensitive adhesive sheet for temporarily fixing electronic components according to one embodiment of the present invention. [Figure 2] FIG. 2 is a diagram illustrating a method of using the pressure-sensitive adhesive sheet for temporarily fixing electronic components according to one embodiment of the present invention. [Figure 3] FIG. 2 is a diagram illustrating a method of using the pressure-sensitive adhesive sheet for temporarily fixing electronic components according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0008] A. Overview of adhesive sheets for temporary fixing of electronic components FIG. 1 is a schematic cross-sectional view of a pressure-sensitive adhesive sheet for temporary fixing of electronic components according to one embodiment of the present invention. The pressure-sensitive adhesive sheet for temporary fixing of electronic components 110 includes a laminate structure A including a substrate 10 and a gas-generating layer 20 disposed on at least one side of the substrate 10, and a pressure-sensitive adhesive layer 30 disposed on at least one side of the laminate structure A (the gas-generating layer 20 side in the illustrated example). The gas-generating layer is a layer that decomposes when heat is applied and generates gas. The thermal decomposition of the gas-generating layer is caused by laser light irradiation. The laser light irradiation may cause the gas-generating layer itself to generate heat (i.e., the gas-generating layer may exhibit a photothermal conversion function), or the substrate adjacent to the gas-generating layer may generate heat (i.e., the substrate may exhibit a photothermal conversion function). In one embodiment, the gas generation from the gas-generating layer changes the surface shape of the gas-generating layer, allowing the substrate and the gas-generating layer to easily separate (peel off). In this specification, "thermal decomposition" means that heating at 250°C or higher may result in a weight loss of 5% or more. As long as the effects of the present invention are obtained, the pressure-sensitive adhesive sheet for temporary fixing of electronic components may further include other layers. For example, the pressure-sensitive adhesive sheet 110 may further include another pressure-sensitive adhesive layer 40 arranged on the substrate 10 side of the laminate structure A. Hereinafter, the pressure-sensitive adhesive sheet for temporary fixing of electronic components may also be simply referred to as the pressure-sensitive adhesive sheet.

[0009] In one embodiment, the substrate and the gas generating layer are directly disposed. If the substrate and the gas generating layer are directly disposed, when heat is generated in the substrate, the heat is preferably transferred to the gas generating layer, and gas generation is preferably generated. "Directly disposed" means that no other layer is disposed between the substrate and the gas generating layer, and these layers are in contact with each other.

[0010] The pressure-sensitive adhesive sheet for temporary fixing of electronic components has a transmittance of 75% or less for light with a wavelength of 1032 nm. The pressure-sensitive adhesive sheet for temporary fixing of electronic components has a transmittance of 50% or more for light with a wavelength of 600 nm. The transmittance of light with a wavelength of 1032 nm is preferably 65% ​​or less, more preferably 50% or less, even more preferably 40% or less, particularly preferably 30% or less, and most preferably 20% or less. The lower limit of the transmittance of light with a wavelength of 1032 nm is, for example, 1% (preferably 0.5%). The transmittance of light with a wavelength of 600 nm is preferably 60% or more, more preferably 70% or more, and even more preferably 80% or more. The upper limit of the transmittance of light with a wavelength of 600 nm is, for example, 90% (preferably 95%). The pressure-sensitive adhesive sheet for temporary fixing of electronic components is advantageous not only in that it can absorb laser light and exhibit releasability, but also in that it has excellent visibility through the pressure-sensitive adhesive sheet.

[0011] In one embodiment, the transmittance of the pressure-sensitive adhesive sheet for temporary fixing of electronic components at a wavelength of 355 nm is 50% or less, more preferably 0% to 30%, and even more preferably 0% to 20%. By adjusting the transmittance of the substrate at 355 nm and setting the transmittance of the pressure-sensitive adhesive sheet for temporary fixing of electronic components at 355 nm within this range, it becomes possible to generate heat in the substrate with UV laser light, and it is possible to obtain a pressure-sensitive adhesive sheet for temporary fixing of electronic components that can also exhibit releasability with UV laser light.

[0012] In one embodiment, there is provided a method for separating a temporarily fixed electronic component from a support, the method comprising: placing a pressure-sensitive adhesive sheet for temporarily fixing an electronic component on a support; placing an electronic component on the pressure-sensitive adhesive sheet for temporarily fixing an electronic component; and then irradiating the gas-generating layer or the substrate with light to separate the substrate from the gas-generating layer. More specifically, the method is as follows. In one embodiment, the pressure-sensitive adhesive sheet for temporarily fixing an electronic component is attached to a support via a pressure-sensitive adhesive layer, and an electronic component (e.g., a semiconductor component such as a semiconductor wafer) is placed on the substrate side. In one embodiment, the pressure-sensitive adhesive sheet can behave as shown in FIG. 2 and described below. The pressure-sensitive adhesive sheet 110 shown in FIG. 2 comprises a laminate structure A (substrate / gas-generating layer) and a pressure-sensitive adhesive layer 30 arranged on the gas-generating layer 20 side of the laminate structure A. In this embodiment, the gas-generating layer absorbs IR laser light and exhibits a photothermal conversion function. (1) The adhesive sheet 110 is placed on the support 200 with the adhesive layer 30 facing the support 200, and an electronic component 300, which is the workpiece, is placed on the side of the adhesive sheet 110 opposite the support 200 (FIG. 2(a)). The electronic component 300 can be attached to the adhesive sheet 110 via, for example, another adhesive layer 40. (2) When the adhesive sheet 110 (essentially the gas generating layer) arranged on the support 200 is irradiated with IR laser light (e.g., wavelength of 800 nm or more) from the support 200 side, the gas generating layer 20 generates heat, and the gas generating layer 20 is thermally decomposed to generate gas (Figure 2(b)). (3) As a result, the surface shape of the gas generating layer 20 changes, and the gas generating layer 20 exhibits releasability with respect to the substrate 10. This makes it possible to peel the substrate 10 (substrate 10 with electronic component 300) from the support 200 (FIG. 2(c)). As a result, the electronic component 300 can be separated from the support 200. (4) Next, the laminated structure consisting of the adhesive layer 30 / gas generating layer 20 on the support 200 is peeled off, whereby the clean support 200 with minimal residue can be collected (FIG. 2(d)).

[0013] In another embodiment, the pressure-sensitive adhesive sheet may behave as shown in Figure 3 and described below. Pressure-sensitive adhesive sheet 110 shown in Figure 3 comprises a laminate structure A (substrate / gas-generating layer) and a pressure-sensitive adhesive layer 30 disposed on the gas-generating layer 20 side of laminate structure A. In this embodiment, a substrate capable of absorbing UV laser light is used, and the substrate exhibits a photothermal conversion function. (1) The adhesive sheet 110 is placed on the support 200 with the adhesive layer 30 facing the support 200, and an electronic component 300, which is the workpiece, is placed on the side of the adhesive sheet 110 opposite the support 200 (FIG. 3(a)). The electronic component 300 can be attached to the adhesive sheet 110 via, for example, another adhesive layer 40. (2) When the adhesive sheet 110 (essentially the base material) placed on the support 200 is irradiated with UV laser light (e.g., wavelength of 380 nm or less) from the support 200 side, the base material 10 generates heat, which causes the gas generation layer 20 to thermally decompose and generate gas (Figure 3(b)). (3) As a result, the surface shape of the gas generating layer 20 changes, and the gas generating layer 20 exhibits releasability with respect to the substrate 10. This makes it possible to peel the substrate 10 (substrate 10 with electronic component 300) from the support 200 (FIG. 3(c)). As a result, the electronic component 300 can be separated from the support 200. (4) Next, the laminated structure consisting of the adhesive layer 30 / gas generating layer 20 on the support 200 is peeled off, whereby the clean support 200 with minimal residue can be collected (FIG. 3(d)).

[0014] A pressure-sensitive adhesive sheet having the above-mentioned properties can be obtained, for example, by incorporating a suitable near-infrared absorber into a gas-generating layer formed from a resin. Such a pressure-sensitive adhesive sheet can be configured to have excellent heat resistance and chemical resistance, and is also advantageous in terms of production cost and production control. Furthermore, a pressure-sensitive adhesive sheet that can exhibit releasability even with UV laser light can be obtained, for example, by using a material that can absorb UV light as the material constituting the substrate.

[0015] The adhesive strength of the pressure-sensitive adhesive sheet at 23°C when the pressure-sensitive adhesive layer is attached to PET is preferably 0.2 N / 20 mm to 10 N / 20 mm, more preferably 3 N / 20 mm to 8 N / 20 mm. Within this range, a pressure-sensitive adhesive sheet suitable for temporary fixing applications can be obtained without misalignment on the support. The adhesive strength is measured in accordance with JIS Z 0237:2000. Specifically, the thermally decomposed layer is attached to a glass plate (arithmetic mean surface roughness Ra: 10±8 nm) using a 2 kg roller in one stroke, and then the adhesive sheet is peeled off at a peel angle of 180° and a peel speed (pulling rate) of 300 mm / min.

[0016] The adhesive strength of the pressure-sensitive adhesive sheet at 23°C when the pressure-sensitive adhesive layer is attached to SUS430 is preferably 0.20 N / 20 mm to 10 N / 20 mm, and more preferably 3 N / 20 mm to 7 N / 20 mm. If the adhesive strength is within this range, a pressure-sensitive adhesive sheet suitable for temporary fixing applications can be obtained without misalignment on the support.

[0017] The thickness of the pressure-sensitive adhesive sheet for temporarily fixing electronic components is preferably 10 μm to 500 μm, and more preferably 20 μm to 400 μm.

[0018] B. Gas generation layer In one embodiment, the gas generating layer is a layer capable of absorbing near-infrared rays. More specifically, the transmittance of the gas generating layer at a wavelength of 1032 nm is 75% or less, preferably 50% or less, more preferably 40% or less, even more preferably 35% or less, and most preferably 20% or less. Within such a range, a gas generating layer that favorably absorbs IR laser light and easily generates heat can be formed. The lower limit of the transmittance of the gas generating layer at a wavelength of 1032 nm is, for example, 5% (preferably 1%).

[0019] In one embodiment, the transmittance of the gas generating layer for light having a wavelength of 600 nm is 50% or more, more preferably 60% or more, even more preferably 70% or more, and most preferably 80% or more. Within such a range, a gas generating layer that can contribute to improved visibility can be formed. The upper limit of the transmittance of the gas generating layer for light having a wavelength of 600 nm is, for example, 90% (preferably 95%).

[0020] In one embodiment, the transmittance of the gas generating layer at a wavelength of 355 nm is preferably 40% or more, and more preferably 50% to 95%. Within this range, a pressure-sensitive adhesive sheet that can exhibit releasability even with UV laser light can be obtained by appropriately selecting a UV-absorbing substrate.

[0021] The thickness of the gas generating layer is preferably 1 μm to 100 μm, more preferably 2 μm to 50 μm, even more preferably 3 μm to 30 μm, and particularly preferably 5 μm to 20 μm.

[0022] The 5% weight loss temperature of the gas generation layer is preferably 300°C or higher, more preferably 310°C to 400°C, even more preferably 320°C to 380°C, and particularly preferably 330°C to 370°C. Within this range, a pressure-sensitive adhesive sheet with excellent heat resistance can be obtained. Furthermore, since the RDL formation process is generally performed at a temperature of 250°C or lower, if the 5% weight loss temperature is within the above range, outgassing from the gas generation layer during the RDL formation process is reduced, reducing the impact on electronic components and enabling a stable process. The 5% weight loss temperature refers to the temperature at which the weight of a sample to be evaluated, when heated, decreases by 5% by weight relative to the dry weight of the sample before heating. The 5% weight loss temperature is measured using a differential thermal analyzer under measurement conditions of a heating rate of 10°C / min, a nitrogen atmosphere, and a flow rate of 25 ml / min. The dry weight of a sample refers to the weight of the sample excluding moisture.

[0023] The elastic modulus of the gas generating layer measured by nanoindentation is 100 MPa or more, more preferably 200 MPa to 5 GPa, and even more preferably 300 MPa to 3 GPa. Within this range, the shape of the gas generating layer is favorably changed by gas generation during laser light irradiation, resulting in excellent releasability. The elastic modulus measured by nanoindentation is determined from the applied load-indentation depth curve obtained by continuously measuring the load and indentation depth when an indenter is pressed into a sample, both during loading and unloading. The elastic modulus measured by nanoindentation is obtained by pressing a diamond Berkovich-type (triangular pyramidal) probe perpendicularly against the surface of the object to be measured, and then numerically processing the displacement-load hysteresis curve using software (triboscan) provided with the measurement device. In this specification, the elastic modulus measured by nanoindentation is the elastic modulus measured using a nanoindenter (Triboindenter TI-950 manufactured by Hysitron Inc.) by a single indentation method at a specified temperature (25°C) under measurement conditions of an indentation speed of approximately 500 nm / sec, an extraction speed of approximately 500 nm / sec, and an indentation depth of approximately 100 nm. The elastic modulus of the gas-generating layer can be adjusted by the type of material contained in the layer, the structure of the base polymer that constitutes the material, the type and amount of additives added to the layer, etc.

[0024] In one embodiment, the gas-generating layer contains a near-infrared absorbing agent. In one embodiment, the gas-generating layer can be a layer in which the near-infrared absorbing agent is contained in a resin. The gas-generating layer can be a resin film. The resin film can be, for example, a film in which the near-infrared absorbing agent is contained in a resin (e.g., a single-layer film), or a film consisting of a layer containing a predetermined near-infrared absorbing agent (e.g., a printed layer) and a resin layer.

[0025] As the near-infrared absorbing agent, any suitable near-infrared absorbing agent can be used in any suitable amount as long as it can impart near-infrared absorbing properties and can obtain the effects of the present invention.As the near-infrared absorbing agent, for example, cesium tungsten oxide, lanthanum hexaboride, tin-doped indium oxide, antimony-doped tin oxide, cyanine compounds, phthalocyanine compounds, dithiol metal complexes, naphthoquinone compounds, diimmonium compounds, azo compounds, etc. are used.Among them, cesium tungsten oxide or lanthanum hexaboride are preferred, and cesium tungsten oxide is more preferred.By using such a near-infrared absorbing agent, it is possible to form a gas generating layer that can absorb near-infrared rays to generate heat and also has excellent visible light transmittance.

[0026] Preferably, the near-infrared absorbing agent is a substance containing tungsten, such as cesium tungsten oxide.

[0027] Preferably, a substance containing cesium element is used as the near-infrared absorbing agent, and a preferred example of the substance containing cesium element is cesium tungsten oxide.

[0028] When the gas generating layer contains a resin and a near-infrared absorbing agent, the content of the near-infrared absorbing agent is preferably 1 to 50 parts by weight, more preferably 3 to 40 parts by weight, and even more preferably 5 to 30 parts by weight, relative to 100 parts by weight of the resin.Within such a range, a gas generating layer capable of favorably absorbing IR laser light can be formed.

[0029] Any appropriate resin can be used as the resin constituting the gas generating layer. Examples of resins constituting the gas generating layer include acrylic resins, epoxy resins, polyester resins, polystyrene resins, polyimide resins, and polyurethane resins. Among these, acrylic resins are preferred.

[0030] The gas generating layer is preferably made of a cured product of a curable (e.g., active energy ray-curable or thermosetting) resin composition, more preferably made of a cured product of an active energy ray-curable resin composition, and even more preferably made of a cured product of an acrylic active energy ray-curable resin composition. A gas generating layer formed of a cured product of a curable resin composition is advantageous in that it has excellent heat resistance. In one embodiment, the gas generating layer formed as a cured product of a curable resin composition contains a polymerization initiator. The polymerization initiator is, for example, a photopolymerization initiator or a thermal polymerization initiator. The near-infrared absorber can be contained in the curable resin composition. In one embodiment, the curable resin composition contains a pentaerythritol-based polyfunctional (meth)acrylate. Use of a pentaerythritol-based polyfunctional (meth)acrylate makes it possible to form a gas generating layer with excellent heat resistance.

[0031] In one embodiment, the active energy ray-curable resin composition used is an active energy ray-curable resin composition (A1) that includes a base polymer (or a monomer or oligomer that constitutes the base polymer) that serves as a matrix, and an active energy ray-reactive compound (monomer or oligomer). In another embodiment, an active energy ray-curable resin composition (A2) that includes an active energy ray-reactive polymer as the base polymer is used. In one embodiment, the base polymer has a functional group that can be cleaved by a photopolymerization initiator. Examples of the functional group include functional groups having a carbon-carbon double bond. Examples of active energy rays include gamma rays, ultraviolet rays, visible light, infrared rays (heat rays), radio waves, alpha rays, beta rays, electron beams, plasma flow, ionizing rays, and particle beams. Ultraviolet rays are preferred.

[0032] Examples of the base polymer used in the resin composition (A1) 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-based polymers. These polymers may be used alone or in combination of two or more. Among these, acrylic polymers are preferred.

[0033] Examples of acrylic polymers include homopolymers or copolymers of (meth)acrylic acid esters such as (meth)acrylic acid alkyl esters, (meth)acrylic acid cycloalkyl esters, and (meth)acrylic acid aryl esters; copolymers of the (meth)acrylic acid esters with other copolymerizable monomers, etc. Specific examples of (meth)acrylic acid alkyl esters include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, s-butyl (meth)acrylate, t-butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, and (meth)acrylate. Examples of (meth)acrylic acid C1-20 alkyl esters include nonyl 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 these, (meth)acrylic acid alkyl esters having a linear or branched alkyl group having 4 to 18 carbon atoms can be preferably used.

[0034] Examples of the other copolymerizable monomers include functional group-containing monomers such as carboxyl group-containing monomers, acid anhydride monomers, hydroxyl group-containing monomers, glycidyl group-containing monomers, sulfonic acid group-containing monomers, phosphate group-containing monomers, acrylamide, and acrylonitrile. Examples of the carboxyl group-containing monomers include acrylic acid, methacrylic acid, carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, itaconic acid, maleic acid, fumaric acid, and crotonic acid. Examples of the acid anhydride monomers include maleic anhydride and itaconic anhydride. Examples of the hydroxyl group-containing monomers include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, 12-hydroxylauryl (meth)acrylate, and (4-hydroxymethylcyclohexyl)methyl (meth)acrylate. Examples of glycidyl group-containing monomers include glycidyl (meth)acrylate and methylglycidyl (meth)acrylate. Examples of sulfonic acid group-containing monomers include styrenesulfonic acid, allylsulfonic acid, 2-(meth)acrylamido-2-methylpropanesulfonic acid, (meth)acrylamidopropanesulfonic acid, sulfopropyl (meth)acrylate, and (meth)acryloyloxynaphthalenesulfonic acid. Examples of phosphate group-containing monomers include 2-hydroxyethyl acryloyl phosphate. Examples of acrylamides include N-acryloylmorpholine. These may be used alone or in combination of two or more. The content of the structural unit derived from the copolymerizable monomer is preferably 60 parts by weight or less, more preferably 40 parts by weight or less, per 100 parts by weight of the base polymer (acrylic polymer).

[0035] In one embodiment, an acrylic monomer that has a glass transition temperature of 40°C or higher when made into a homopolymer is used as the monomer constituting the acrylic polymer. That is, the acrylic polymer contains a structural unit derived from an acrylic monomer that has a glass transition temperature of 40°C or higher when made into a homopolymer. Examples of such an acrylic monomer include methyl methacrylate, glycidyl methacrylate, isobutyl methacrylate, acrylonitrile, methacrylonitrile, isopropylacrylamide, acryloylmorpholine, and isobornyl acrylate. Of these, methyl methacrylate is preferred. Use of an acrylic polymer containing a structural unit derived from such a monomer can prevent stickiness caused by decomposition products due to laser light irradiation. The content of the structural unit derived from an acrylic monomer that has a glass transition temperature of 40°C or higher when made into a homopolymer is preferably 30 to 80 parts by weight, more preferably 40 to 75 parts by weight, relative to 100 parts by weight of the base polymer (acrylic polymer). Within this range, the above-mentioned effects are significant.

[0036] The acrylic polymer may contain a structural unit derived from a polyfunctional monomer. The use of a polyfunctional monomer allows for the formation of a gas generating layer with excellent heat resistance. Examples of polyfunctional monomers include 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 (meth)acrylate (i.e., polyglycidyl (meth)acrylate), polyester (meth)acrylate, and urethane (meth)acrylate. These may be used alone or in combination of two or more. When a polyfunctional monomer-derived structural unit is contained, the content of the polyfunctional monomer-derived structural unit is preferably 30 parts by weight or more, more preferably 40 parts by weight or more, relative to 100 parts by weight of the base polymer (acrylic polymer). The upper limit of the content of the polyfunctional monomer-derived structural unit is preferably 400 parts by weight or less, more preferably 300 parts by weight or less, relative to 100 parts by weight of the base polymer (acrylic polymer).

[0037] The weight-average molecular weight of the acrylic polymer is preferably from 10,000 to 1,500,000, and more preferably from 20,000 to 1,000,000. The weight-average molecular weight can be measured by GPC (solvent: THF).

[0038] Examples of the active energy ray-reactive compound that can be used in the resin composition (A1) include photoreactive monomers or oligomers having a functional group with a polymerizable carbon-carbon multiple bond, such as an acryloyl group, a methacryloyl group, a vinyl group, an allyl group, or an acetylene group. Specific examples of the photoreactive monomer include esters of (meth)acrylic acid and polyhydric alcohols 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, and polyethylene glycol di(meth)acrylate; polyfunctional urethane (meth)acrylate; epoxy (meth)acrylate; oligoester (meth)acrylate; etc. Also usable are monomers such as methacryloisocyanate, 2-methacryloyloxyethyl isocyanate (2-isocyanatoethyl methacrylate), and m-isopropenyl-α,α-dimethylbenzyl isocyanate. Specific examples of the photoreactive oligomer include dimers to pentamers of the above-mentioned monomers. The molecular weight of the photoreactive oligomer is preferably 100 to 3,000.

[0039] In one embodiment, the active energy ray-curable resin composition (A1) contains a pentaerythritol-based polyfunctional (meth)acrylate as the active energy ray-reactive compound. The pentaerythritol-based polyfunctional (meth)acrylate can be obtained by esterifying some or all of the hydroxyl groups of pentaerythritol or a polymer thereof with a (meth)acrylate. By using a pentaerythritol-based polyfunctional (meth)acrylate as the active energy ray-reactive compound, a gas generating layer having excellent heat resistance can be formed.

[0040] Furthermore, as the active energy ray reactive compound, a monomer such as epoxidized butadiene, glycidyl methacrylate, acrylamide, vinyl siloxane, or the like, or an oligomer composed of such a monomer may be used.

[0041] In the resin composition (A1), the content of the active energy ray reactive compound is preferably 0.1 to 500 parts by weight, more preferably 5 to 300 parts by weight, and even more preferably 40 to 150 parts by weight, relative to 100 parts by weight of the base polymer.

[0042] Examples of the active energy ray-reactive polymer (base polymer) contained in the resin composition (A2) include polymers having functional groups with carbon-carbon multiple bonds, such as acryloyl groups, methacryloyl groups, vinyl groups, allyl groups, acetylene groups, etc. Specific examples of the active energy ray-reactive polymer include polymers composed of polyfunctional (meth)acrylates (for example, polymers containing structural units derived from polyfunctional monomers), photocationic polymerization polymers, cinnamoyl group-containing polymers such as polyvinyl cinnamate, diazotized amino novolac resins, polyacrylamides, etc.

[0043] In one embodiment, an active energy ray-reactive polymer is used, which is constructed by introducing an active energy ray-polymerizable carbon-carbon multiple bond into the side chain, main chain, and / or main chain terminal of the acrylic polymer. A method for introducing a radiation-polymerizable carbon-carbon double bond into an acrylic polymer includes, for example, copolymerizing raw material monomers including a monomer having a predetermined functional group (first functional group) to obtain an acrylic polymer, and then subjecting a compound having a radiation-polymerizable carbon-carbon double bond and a predetermined functional group (second functional group) capable of reacting with and bonding to the first functional group to a condensation reaction or addition reaction with the acrylic polymer while maintaining the radiation polymerizability of the carbon-carbon double bond.

[0044] Examples of combinations of the first functional group and the second functional group include a carboxyl group and an epoxy group, an epoxy group and a carboxyl group, a carboxyl group and an aziridyl group, an aziridyl group and a carboxyl group, a hydroxyl group and an isocyanate group, and an isocyanate group and a hydroxyl group. Among these combinations, a hydroxyl group and an isocyanate group, or an isocyanate group and a hydroxyl group, is preferred from the viewpoint of ease of reaction tracking. Furthermore, while producing a polymer having a highly reactive isocyanate group is technically difficult, from the viewpoint of ease of production or availability of the acrylic polymer, it is more preferred that the first functional group on the acrylic polymer be a hydroxyl group and the second functional group be an isocyanate group. In this case, examples of isocyanate compounds having both a radiation-polymerizable carbon-carbon double bond and an isocyanate group as the second functional group include methacryloyl isocyanate, 2-methacryloyloxyethyl isocyanate, and m-isopropenyl-α,α-dimethylbenzyl isocyanate. Furthermore, the acrylic polymer having a first functional group is preferably one that contains a structural unit derived from the above-mentioned hydroxy group-containing monomer, and is also preferably one that contains a structural unit derived from an ether compound such as 2-hydroxyethyl vinyl ether, 4-hydroxybutyl vinyl ether, or diethylene glycol monovinyl ether.

[0045] The resin composition (A2) may further contain the active energy ray-reactive compound (monomer or oligomer).

[0046] In one embodiment, the active energy ray-curable resin composition includes a polymerization initiator. Examples of the polymerization initiator that can be used include a photopolymerization initiator and a thermal polymerization initiator, and a photopolymerization initiator is preferred.

[0047] Any suitable initiator can be used as the photopolymerization initiator. Examples of the photopolymerization initiator include α-ketol compounds such as 4-(2-hydroxyethoxy)phenyl(2-hydroxy-2-propyl)ketone, α-hydroxy-α,α'-dimethylacetophenone, 2-methyl-2-hydroxypropiophenone, and 1-hydroxycyclohexylphenyl ketone; acetophenone compounds such as methoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxyacetophenone, and 2-methyl-1-[4-(methylthio)-phenyl]-2-morpholinopropane-1; benzoin ether compounds such as benzoin ethyl ether, benzoin isopropyl ether, and anisoin methyl ether; and ketal compounds such as benzyl dimethyl ketal. Examples of suitable photopolymerization initiators include aromatic sulfonyl chloride compounds such as 2-naphthalenesulfonyl chloride, photoactive oxime compounds such as 1-phenone-1,1-propanedione-2-(o-ethoxycarbonyl)oxime, benzophenone compounds such as benzophenone, benzoylbenzoic acid, and 3,3'-dimethyl-4-methoxybenzophenone, thioxanthone compounds such as thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 2,4-dichlorothioxanthone, 2,4-diethylthioxanthone, and 2,4-diisopropylthioxanthone, camphorquinone, halogenated ketones, acylphosphinoxides, and acylphosphonates. The amount of the photopolymerization initiator used can be set to any appropriate amount.

[0048] In one embodiment, the active energy ray-curable resin composition may contain a photosensitizer.

[0049] Preferably, the active energy ray-curable resin composition contains a crosslinking agent, such as an isocyanate-based crosslinking agent, an epoxy-based crosslinking agent, an oxazoline-based crosslinking agent, an aziridine-based crosslinking agent, a melamine-based crosslinking agent, a peroxide-based crosslinking agent, a urea-based crosslinking agent, a metal alkoxide-based crosslinking agent, a metal chelate-based crosslinking agent, a metal salt-based crosslinking agent, a carbodiimide-based crosslinking agent, or an amine-based crosslinking agent.

[0050] The content of the crosslinking agent is preferably 0.01 to 20 parts by weight relative to 100 parts by weight of the base polymer of the resin composition.

[0051] In one embodiment, an epoxy-based crosslinking agent is preferably used. Use of an epoxy-based crosslinking agent makes it possible to form a thermal decomposition layer having a high 5% weight loss temperature after ultraviolet irradiation. Examples of the epoxy-based crosslinking agent include N,N,N',N'-tetraglycidyl-m-xylylenediamine, diglycidylaniline, 1,3-bis(N,N-glycidylaminomethyl)cyclohexane (manufactured by Mitsubishi Gas Chemical Company, Inc., trade name "Tetrad C"), 1,6-hexanediol diglycidyl ether (manufactured by Kyoeisha Chemical Co., Ltd., trade name "Epolite 1600"), neopentyl glycol diglycidyl ether (manufactured by Kyoeisha Chemical Co., Ltd., trade name "Epolite 1500NP"), ethylene glycol diglycidyl ether (manufactured by Kyoeisha Chemical Co., Ltd., trade name "Epolite 1500NP"), and the like. Licor 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 Corporation, trade name "Denacol") Examples of suitable epoxy crosslinking agents include glycerol polyglycidyl ether (manufactured by Nagase ChemteX Corporation under the trade name "Denacol EX-611"), glycerol polyglycidyl ether (manufactured by Nagase ChemteX Corporation under the trade name "Denacol EX-314"), pentaerythritol polyglycidyl ether, polyglycerol polyglycidyl ether (manufactured by Nagase ChemteX Corporation under the trade name "Denacol EX-512"), sorbitan polyglycidyl ether, trimethylolpropane polyglycidyl ether, adipic acid diglycidyl ester, o-phthalic acid diglycidyl ester, triglycidyl tris(2-hydroxyethyl)isocyanurate, resorcinol diglycidyl ether, bisphenol-S-diglycidyl ether, and epoxy resins having two or more epoxy groups in the molecule. The content of the epoxy crosslinking agent can be set to any appropriate amount depending on the desired properties, and is typically 0.01 to 10 parts by weight, and more preferably 0.05 to 7 parts by weight, per 100 parts by weight of the base polymer.

[0052] In one embodiment, an isocyanate-based crosslinking agent is preferably used. Specific examples of the isocyanate-based crosslinking agent include lower aliphatic polyisocyanates such as butylene diisocyanate and hexamethylene diisocyanate; alicyclic isocyanates such as cyclopentylene diisocyanate, cyclohexylene diisocyanate and isophorone diisocyanate; aromatic isocyanates such as 2,4-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate and xylylene diisocyanate; and isocyanate adducts such as trimethylolpropane / tolylene 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"). Preferably, a crosslinking agent having three or more isocyanate groups is used. The content of the isocyanate crosslinking agent can be set to any appropriate amount depending on the desired properties, and is typically 0.1 to 20 parts by weight, more preferably 0.5 to 10 parts by weight, per 100 parts by weight of the base polymer.

[0053] The active energy ray-curable resin composition may further contain any appropriate additives as necessary, such as an active energy ray polymerization accelerator, a radical scavenger, a tackifier, a plasticizer (e.g., a trimellitic acid ester-based plasticizer, a pyromellitic acid ester-based plasticizer, etc.), a pigment, a dye, a filler, an antioxidant, a conductive material, an antistatic agent, an ultraviolet absorber, a light stabilizer, a release agent, a softener, a surfactant, a flame retardant, and an antioxidant.

[0054] (Method for forming gas generation layer) The gas generating layer can be formed by any appropriate method, which may include, for example, a step (A) of preparing a composition for forming a gas generating layer, a step (B) of applying the composition for forming a gas generating layer to the substrate, and a step (C) of curing the applied layer of the composition for forming a gas generating layer.

[0055] The gas generating layer-forming composition contains a near-infrared absorbing agent. In one embodiment, the gas generating layer-forming composition may be the curable resin composition (preferably the active energy ray-curable resin composition) containing the near-infrared absorbing agent. In one embodiment, the near-infrared absorbing agent is a substance containing elemental tungsten and / or a substance containing elemental cesium. That is, in one embodiment, the gas generating layer-forming composition contains a substance containing elemental tungsten and / or a substance containing elemental cesium.

[0056] Any appropriate method can be used for applying the gas-generating layer-forming composition, such as bar coater coating, air knife coating, gravure coating, gravure reverse coating, reverse roll coating, lip coating, die coating, dip coating, offset printing, flexographic printing, and screen printing.

[0057] When the gas-generating layer-forming composition contains an active energy ray-reactive compound, the coating layer of the gas-generating layer-forming composition is irradiated with active energy rays such as ultraviolet rays in step (C). The irradiation conditions can be any appropriate conditions depending on the composition of the gas-generating layer-forming composition.

[0058] When the gas-generating layer-forming composition is thermosetting, a heat treatment is carried out in step (C). The heating conditions can be any appropriate conditions depending on the composition of the gas-generating layer-forming composition.

[0059] C. Base material The substrate may be made of any appropriate resin, such as polyolefin resins such as polyethylene resins, polypropylene resins, polybutene resins, and polymethylpentene resins, polyurethane resins, polyester resins, polyimide resins, polyether ketone resins, polystyrene resins, polyvinyl chloride resins, polyvinylidene chloride resins, fluorine resins, silicone resins, cellulose resins, and ionomer resins.

[0060] In one embodiment, the substrate is made of a polyimide resin, a polyester resin, or a polyether ether ketone resin. Among these, a polyimide resin is preferred. These resins have UV absorption properties, and the use of such resins allows for a wider range of laser types to be selected for the pressure-sensitive adhesive sheet.

[0061] The thickness of the substrate is preferably 2 μm to 300 μm, more preferably 2 μm to 100 μm, and even more preferably 2 μm to 50 μm.

[0062] In one embodiment, the transmittance of the substrate to light with a wavelength of 1032 nm is 60% to 95%, and preferably 70% to 90%.

[0063] In one embodiment, the transmittance of the substrate at a wavelength of 600 nm is 50% or more, more preferably 60% or more, even more preferably 70% or more, and most preferably 80% or more. The upper limit of the transmittance of the substrate at a wavelength of 600 nm is, for example, 95% (preferably 99%).

[0064] In one embodiment, the transmittance of the substrate to light with a wavelength of 355 nm is preferably 50% or less, and more preferably 0% to 20%. Within this range, a pressure-sensitive adhesive sheet that can exhibit releasability even with UV laser light can be obtained.

[0065] The tensile modulus of the substrate at 200°C is preferably 5 MPa to 2 GPa, more preferably 10 MPa to 1.8 GPa, even more preferably 500 MPa to 1.8 GPa, and particularly preferably 1 GPa to 1.5 GPa. Within such ranges, the substrate effectively blocks gas generated by laser light irradiation, and favorable releasability is achieved due to changes in the shape of the surface of the gas generating layer. The tensile modulus can be measured using a dynamic viscoelasticity measuring device. Specific measurement methods will be described later.

[0066] The 5% weight loss temperature of the substrate is preferably 300°C or higher, more preferably 350°C to 650°C, even more preferably 380°C to 600°C, and particularly preferably 400°C to 590°C. Within this range, a pressure-sensitive adhesive sheet with excellent heat resistance can be obtained. Furthermore, since the RDL formation process is generally carried out at a temperature of 250°C or lower, a 5% weight loss temperature within the above range reduces outgassing from the substrate during the RDL formation process, reducing the impact on electronic components and enabling a stable process. Furthermore, a 5% weight loss temperature within the above range of the substrate reduces damage during laser irradiation, allowing the tape (pressure-sensitive adhesive layer / substrate) to be removed from electronic components without breaking when peeled off.

[0067] D. Laminated structure A (substrate / gas generating layer) The transmittance of light having a wavelength of 1032 nm through the laminate structure A comprising the substrate and the gas generating layer is preferably 75% or less, more preferably 65% ​​or less, even more preferably 50% or less, still more preferably 40% or less, particularly preferably 30% or less, and most preferably 20% or less. Within such a range, a pressure-sensitive adhesive sheet capable of favorably absorbing IR laser light can be formed.

[0068] The transmittance of the laminate structure A at light having a wavelength of 600 nm is preferably 50% or more, more preferably 60% or more, even more preferably 70% or more, and particularly preferably 80% or more. The upper limit of the transmittance at light having a wavelength of 600 nm is, for example, 90% (preferably 95%). An adhesive sheet having such a laminate structure A is advantageous not only in that it can absorb IR laser light and generate heat, but also in that it has excellent visibility through the adhesive sheet.

[0069] In one embodiment, the transmittance of light with a wavelength of 355 nm through the laminate structure A is 50% or less, preferably 40% or less, more preferably 20% or less, particularly preferably 10% or less, and most preferably 0%. By adjusting the transmittance of light with a wavelength of 355 nm through the substrate and setting the transmittance of light with a wavelength of 355 nm through the laminate structure A within this range, it becomes possible for the substrate to be heated by UV laser light, and a pressure-sensitive adhesive sheet that can also exhibit releasability when exposed to UV laser light can be obtained.

[0070] The thickness of the laminate structure A is preferably 10 μm to 200 μm, and more preferably 20 μm to 150 μm.

[0071] E. Adhesive layer The pressure-sensitive adhesive layer includes any suitable pressure-sensitive adhesive. For example, it includes a pressure-sensitive adhesive or a curable pressure-sensitive adhesive. The curable pressure-sensitive adhesive may be the active energy ray-curable resin composition. The pressure-sensitive adhesive layer can be formed by applying a pressure-sensitive adhesive to the laminate structure A (substrate / gas-generating layer) by any suitable method.

[0072] Examples of the pressure-sensitive adhesive include acrylic pressure-sensitive adhesives, silicone pressure-sensitive adhesives, epoxy pressure-sensitive adhesives, styrene thermoplastic elastomers, and ester pressure-sensitive adhesives. In one embodiment, an acrylic pressure-sensitive adhesive is used. Examples of acrylic pressure-sensitive adhesives are described below.

[0073] (base polymer) Examples of the acrylic adhesive include an acrylic adhesive having as a base polymer an acrylic polymer (homopolymer or copolymer) using one or more (meth)acrylic acid alkyl esters as a monomer component. Specific examples of the (meth)acrylic acid alkyl ester include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, s-butyl (meth)acrylate, t-butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, and methyl (meth)acrylate. Examples of (meth)acrylic acid C1-20 alkyl esters include nonyl 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 these, (meth)acrylic acid alkyl esters having a linear or branched alkyl group having 4 to 18 carbon atoms can be preferably used. The content of the (meth)acrylic acid alkyl ester structural unit in the acrylic polymer is preferably 70 to 100 parts by weight, more preferably 75 to 99.9 parts by weight, and even more preferably 80 to 99.9 parts by weight, relative to 100 parts by weight of the acrylic polymer.

[0074] The acrylic polymer may contain, as necessary, a structural unit derived from another monomer copolymerizable with the (meth)acrylic acid alkyl ester, for the purpose of modifying cohesive strength, heat resistance, crosslinkability, etc., improving the dimensional stability of the pressure-sensitive adhesive layer, etc. Examples of such monomers include the following monomers. Carboxy group-containing monomers: for example, ethylenically unsaturated monocarboxylic acids such as acrylic acid (AA), methacrylic acid (MAA), and crotonic acid; ethylenically unsaturated dicarboxylic acids such as maleic acid, itaconic acid, and citraconic acid, and their anhydrides (maleic anhydride, itaconic anhydride, etc.); Hydroxyl group-containing monomers: for example, hydroxyalkyl (meth)acrylates such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, and 2-hydroxybutyl (meth)acrylate; unsaturated alcohols such as vinyl alcohol and allyl alcohol; ether compounds such as 2-hydroxyethyl vinyl ether, 4-hydroxybutyl vinyl ether, and diethylene glycol monovinyl ether; Amino group-containing monomers: for example, aminoethyl (meth)acrylate, N,N-dimethylaminoethyl (meth)acrylate, t-butylaminoethyl (meth)acrylate; Epoxy group-containing monomers: for example, glycidyl (meth)acrylate, methyl glycidyl (meth)acrylate, allyl glycidyl ether; Cyano group-containing monomers: for example, acrylonitrile, methacrylonitrile; Keto group-containing monomers: for example, diacetone (meth)acrylamide, diacetone (meth)acrylate, vinyl methyl ketone, vinyl ethyl ketone, allyl acetoacetate, vinyl acetoacetate; Monomers having a nitrogen atom-containing ring: for example, N-vinyl-2-pyrrolidone, N-methylvinylpyrrolidone, N-vinylpyridine, N-vinylpiperidone, N-vinylpyrimidine, N-vinylpiperazine, N-vinylpyrazine, N-vinylpyrrole, N-vinylimidazole, N-vinyloxazole, N-vinylmorpholine, N-vinylcaprolactam, N-(meth)acryloylmorpholine; Alkoxysilyl group-containing monomers: for example, 3-(meth)acryloxypropyltrimethoxysilane, 3-(meth)acryloxypropyltriethoxysilane, 3-(meth)acryloxypropylmethyldimethoxysilane, 3-(meth)acryloxypropylmethyldiethoxysilane; Isocyanate group-containing monomers: (meth)acryloyl isocyanate, 2-(meth)acryloyloxyethyl isocyanate, m-isopropenyl-α,α-dimethylbenzyl isocyanate. These monomers may be used alone or in combination of two or more.

[0075] The weight-average molecular weight of the acrylic polymer is preferably 600,000 to 1,600,000, more preferably 800,000 to 1,500,000. Within this range, a pressure-sensitive adhesive layer can be formed that has excellent heat resistance, excellent dimensional stability at high temperatures, and suppresses outgassing due to heating. The weight-average molecular weight can be measured by GPC (solvent: THF).

[0076] (additives) The acrylic pressure-sensitive adhesive may contain any appropriate additives as needed, such as crosslinking agents, crosslinking catalysts, tackifiers, plasticizers, pigments, dyes, fillers, antioxidants, conductive materials, antistatic agents, UV absorbers, light stabilizers, release modifiers, softeners, surfactants, flame retardants, and antioxidants.

[0077] Examples of the crosslinking agent include isocyanate-based crosslinking agents, epoxy-based crosslinking agents, melamine-based crosslinking agents, peroxide-based crosslinking agents, as well as urea-based crosslinking agents, metal alkoxide-based crosslinking agents, metal chelate-based crosslinking agents, metal salt-based crosslinking agents, carbodiimide-based crosslinking agents, oxazoline-based crosslinking agents, aziridine-based crosslinking agents, and amine-based crosslinking agents. Of these, epoxy-based crosslinking agents and isocyanate-based crosslinking agents are preferred.

[0078] Examples of the epoxy crosslinking agent include N,N,N',N'-tetraglycidyl-m-xylylenediamine, diglycidylaniline, 1,3-bis(N,N-glycidylaminomethyl)cyclohexane (manufactured by Mitsubishi Gas Chemical Company, Inc., 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 1500NP"), and ethylene glycol diglycidyl ether (manufactured by Kyoeisha Chemical Co., Ltd., trade name "Epolight 1500NP"). Licor 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 Corporation, trade name "Denacol") EX-611), glycerol polyglycidyl ether (manufactured by Nagase ChemteX Corporation, trade name "Denacol EX-314"), pentaerythritol polyglycidyl ether, polyglycerol polyglycidyl ether (manufactured by Nagase ChemteX Corporation, trade name "Denacol EX-512"), sorbitan polyglycidyl ether, trimethylolpropane polyglycidyl ether, adipic acid diglycidyl ester, o-phthalic acid diglycidyl ester, triglycidyl tris(2-hydroxyethyl)isocyanurate, resorcinol diglycidyl ether, bisphenol-S-diglycidyl ether, and epoxy resins having two or more epoxy groups in the molecule. The content of the epoxy-based crosslinking agent can be set to any appropriate amount depending on the desired adhesive strength, viscoelasticity, dimensional stability, and outgassing properties of the adhesive layer, and is typically 0.01 to 10 parts by weight, and more preferably 0.03 to 7 parts by weight, per 100 parts by weight of the base polymer.

[0079] Specific examples of the isocyanate-based crosslinking agent include lower aliphatic polyisocyanates such as butylene diisocyanate and hexamethylene diisocyanate; alicyclic isocyanates such as cyclopentylene diisocyanate, cyclohexylene diisocyanate and isophorone diisocyanate; aromatic isocyanates such as 2,4-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate and xylylene diisocyanate; and isocyanate adducts such as trimethylolpropane / tolylene 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-based crosslinking agent can be set to any appropriate amount depending on the desired adhesive strength, elasticity of the adhesive layer, dimensional stability, outgassing properties, etc., and is typically 0.1 to 20 parts by weight, and more preferably 0.5 to 10 parts by weight, per 100 parts by weight of the base polymer.

[0080] In one embodiment, a heat-resistant adhesive is used as the adhesive contained in the adhesive layer. By providing an adhesive layer composed of a heat-resistant adhesive, it is possible to prevent scorching (adhesive residue) on the light-transmitting support substrate when irradiated with laser light. In this specification, a heat-resistant adhesive means an adhesive that has a predetermined adhesive strength in an environment of 260°C. It is preferable that the heat-resistant adhesive can be used in an environment of 260°C without leaving any adhesive residue. Preferably, the heat-resistant adhesive contains an acrylic resin, a silicone resin, or the like as a base polymer.

[0081] The thickness of the pressure-sensitive adhesive layer is preferably 5 μm to 100 μm, and more preferably 10 μm to 50 μm.

[0082] The pressure-sensitive adhesive layer preferably has a transmittance of 75% or more, more preferably 85% or more, and even more preferably 90% or more at a wavelength of 1032 nm. The upper limit of the transmittance of 1032 nm light is, for example, 97% (preferably 98%).

[0083] The pressure-sensitive adhesive layer preferably has a transmittance of 75% or more, more preferably 85% or more, and even more preferably 90% or more for light with a wavelength of 600 nm. The upper limit of the transmittance for light with a wavelength of 1032 nm is, for example, 97% (preferably 98%).

[0084] The pressure-sensitive adhesive layer preferably has a transmittance of 75% or more, more preferably 85% or more, and even more preferably 90% or more for light with a wavelength of 355 nm. The upper limit of the transmittance for light with a wavelength of 1032 nm is, for example, 97% (preferably 98%).

[0085] F. Use of adhesive sheets for temporary fixing of electronic components The pressure-sensitive adhesive sheet for temporarily fixing electronic components can be used as described in Section A using FIGS. 2 and 3.

[0086] Examples of electronic components that are workpieces include semiconductor wafers, semiconductor packages, semiconductor chips, insulating materials for circuit boards, die attach films, semiconductor encapsulation resins, semiconductor protective films, resin compositions for forming semiconductor protective films, metal materials, ceramic materials, etc. A plurality of the above electronic components may be arranged, or one electronic component may be arranged.

[0087] The electronic component can be attached to the pressure-sensitive adhesive sheet via, for example, another pressure-sensitive adhesive layer disposed on the opposite side of the substrate from the gas-generating layer.

[0088] The support may be made of any suitable material. Examples of suitable supports include glass, such as borosilicate glass and quartz glass; sapphire; and acrylic resins, such as PMMA (polymethyl methacrylate) and PC (polycarbonate). In one embodiment, a support without an organic layer on its surface is used. The arithmetic surface roughness Ra of the support is, for example, 0.3 nm to 100 nm, and more preferably 0.4 nm to 50 nm. The arithmetic surface roughness Ra can be measured in accordance with JIS B 0601. Generally, a smaller surface roughness of the support is preferable from the viewpoint of preventing residues. Furthermore, the support is preferably optically transparent in the ultraviolet to infrared range. In particular, the support is preferably optically transparent to laser light of any selected wavelength. The transmittance of the support at the wavelength of laser light is, for example, 50% or more, and more preferably 60% or more. The water contact angle of the support surface is, for example, 0° to 150°, and more preferably 3° to 120°. The present invention has the advantage that it can achieve favorable peeling even when using a support that has traditionally been difficult to achieve good peeling (for example, residue is generated or pickup properties are poor), i.e., it can broaden the range of support options.

[0089] After placing the electronic component on the pressure-sensitive adhesive sheet (i.e., the state shown in FIG. 2(a)), the electronic component may be subjected to a predetermined process, such as grinding, dicing, die bonding, wire bonding, etching, chemical cleaning, vapor deposition, molding, rewiring layer formation, through-hole formation, or device surface protection.

[0090] The laser light used may have any suitable wavelength depending on the configuration of the pressure-sensitive adhesive sheet. The conditions for laser light irradiation may also be any suitable conditions depending on the configuration of the pressure-sensitive adhesive sheet. In one embodiment, IR laser light is used as the laser light. The wavelength of the IR laser light is preferably 800 nm or more, more preferably 800 nm to 10,600 nm, and even more preferably 900 nm to 1,200 nm. The output of the IR laser light is, for example, 0.01 W to 10 W. In another embodiment, UV laser light is used as the laser light. The wavelength of the UV laser light is preferably 380 nm or less, more preferably 150 nm to 380 nm, and even more preferably 240 nm to 360 nm. The output of the UV laser light is, for example, 0.1 W to 2.0 W. UV laser light can be selected when the substrate is capable of absorbing UV laser light. When irradiated with UV laser light, the substrate generates heat, causing thermal decomposition of the gas-generating layer, thereby exhibiting releasability. [Example]

[0091] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. Evaluation methods in the examples are as follows. In the examples, "parts" and "%" are by weight unless otherwise specified.

[0092] [evaluation] (1) Tensile modulus of the base material at 200°C The tensile modulus at 200° C. was measured under the following conditions using a dynamic viscoelasticity measuring device (manufactured by TA Instrument, trade name "RSA-3"). Measurement frequency: 1Hz Distortion: 0.05% Chuck distance: 20mm Sample width: 10mm Heating rate from 0℃ to 250℃ at 5℃ / min (2) 5% weight loss temperature of the substrate, gas generation layer, and laminate structure A Using a differential thermal analyzer (manufactured by TA Instruments, product name "Discovery TGA"), the temperature was increased at 10°C / min in a N2 atmosphere at a flow rate of 25 ml / min, and the temperature at which the weight of a given sample decreased by 5% relative to the dry weight of the sample before heating was measured. The dry weight of the sample means the weight excluding water in the sample. Specifically, approximately 0.01 g of the evaluation sample was placed in the analyzer, heated from 20°C to 110°C at the above heating rate, and then cooled from 110°C to 20°C at a rate of 10°C / min to remove the effect of moisture and obtain the dry weight. The sample was then heated again at the above heating rate from 20°C to 500°C, while measuring the weight loss. From the obtained data, the temperature at which the weight loss was 5% was extracted. (3) Light transmittance of laminate structure A, pressure-sensitive adhesive sheet and pressure-sensitive adhesive layer The samples were set in a spectrophotometer (product name "UV-VIS ultraviolet-visible spectrophotometer SolidSpec3700", manufactured by Shimadzu Corporation) so that incident light was perpendicular to the sample, and the light transmittance in the wavelength range of 300 nm to 2500 nm was measured. The transmittance at wavelengths of 355 nm, 600 nm, and 1032 nm was extracted from the obtained transmission spectrum. (4) Laser debonding evaluation using an IR laser The adhesive layer on the substrate side of the adhesive sheet (thickness: 10 μm) was attached with a hand roller to a thin glass plate (50 mm wide, 70 mm long, and 0.12 mm thick) simulating a workpiece such as a semiconductor wafer (Matsunami Glass Co., Ltd., rectangular cover glass, product name "C050701"). The adhesive sheet was then cut to the size of the thin glass plate. The adhesive layer on the gas-generating layer side (thickness: 30 μm, 1032 nm light transmittance: 93.91%) was then laminated with a hand roller to a support (thick glass plate (Matsunami Glass Co., Ltd., large slide glass, standard large, white edge polished, product name "S9112") simulating a light-transmitting support substrate, 52 mm wide, 76 mm long, and 1.0 mm thick). The laminate was then placed in an autoclave and heated to degass (40 °C, 5 kgf, 10 minutes) to remove any air bubbles trapped in the laminate, and a laminate sample was prepared. The prepared laminate sample was irradiated with laser light from the support side to evaluate laser debonding. Specifically, a laser with a wavelength of 1032 nm and a beam diameter of approximately 200 μm was used, and pulse scanning was performed at an output of 8.4 W and a frequency of 25 kHz so that the vertical and horizontal pitches were approximately 60 μm. After irradiating the laser light to the laminate sample, the debonding property was evaluated according to the following criteria. The evaluation of laser debondability was carried out in the debonding process between thin glass and thick glass. When the laminate sample could be easily debonded by lifting one point on the outer periphery with the cutter blade, the debonding workability was evaluated as pass (◯); when the entire outer periphery had to be lifted with the cutter blade to finally debond, the debonding workability was evaluated as △; and when the cutter blade was inserted into the outer periphery but the debonding was not possible and the thin glass (workpiece) broke, the debonding workability was evaluated as fail (×). (5) Laser debonding evaluation using UV laser A laminate sample was obtained in the same manner as in the above evaluation (4). The prepared laminate sample was irradiated with laser light from the support side to evaluate the laser debonding property. Specifically, the wavelength was 355 nm, the beam width was approximately 10 μm, the beam length was approximately 1.5 mm, and the energy density was 0.5 J / cm. 2 Using a line laser, pulse scanning was performed at an output of 0.75 W and a frequency of 10 kHz so that the interval between line centers was approximately 10 μm in the width direction and an overlap of approximately 0.2 mm or more in the length direction. (6) Chemical resistance 0.1 mL of N-methyl-2-pyrrolidone (Kishida Chemical Co., Ltd.) was dropped onto the gas generating layer, and after leaving it at 25°C for 15 minutes, the N-methyl-2-pyrrolidone (Kishida Chemical Co., Ltd.) was wiped off, and chemical resistance was evaluated based on whether or not the gas generating layer peeled off. In the table, cases where there was no peeling were marked as pass (◯), and cases where there was peeling were marked as fail (×). (7) Visibility Visibility through the adhesive sheet was evaluated. Specifically, visibility was evaluated based on whether the chip was visible through the adhesive sheet under fluorescent light. If it was visible, it was rated as pass (◯), and if it was not visible, it was rated as fail (×).

[0093] [Production Example 1] Gas generating layer forming composition A Composition A for forming a photothermal conversion layer was prepared by mixing 50 parts by weight of an acrylic polymer having a weight-average molecular weight (Mw) of approximately 22,000, which was a 50:50 (molar ratio) copolymer of methyl methacrylate and acryloyl-modified glycerin methacrylate, 50 parts by weight of a pentaerythritol-based multifunctional acrylate, methyl isobutyl ketone, 0.5 parts by weight of a photopolymerization initiator (manufactured by BASF, product name "Omnirad127D"), 15 parts by weight of a near-infrared absorber (cesium tungsten oxide dispersion, product name "YMF-02A", manufactured by Sumitomo Metal Mining Co., Ltd.), and ethyl acetate.

[0094] [Production Example 2] Gas generating layer forming composition B Composition B for forming a gas generating layer was prepared in the same manner as in Production Example 1, except that the amount of infrared absorber (cesium tungsten oxide dispersion, product name "YMF-02A", manufactured by Sumitomo Metal Mining Co., Ltd.) was changed to 7.5 parts by weight.

[0095] [Production Example 3] Gas-generating layer-forming composition C Composition C for forming a gas generating layer was prepared in the same manner as in Production Example 1, except that the amount of infrared absorber (cesium tungsten oxide dispersion, product name "YMF-02A", manufactured by Sumitomo Metal Mining Co., Ltd.) was 23 parts by weight.

[0096] [Production Example 4] Gas generating layer forming composition D Composition D for forming a photothermal conversion layer was prepared by mixing 50 parts by weight of an acrylic polymer having a weight average molecular weight (Mw) of approximately 22,000, which was obtained by copolymerizing methyl methacrylate and acryloyl-modified glycerin methacrylate in a 50:50 (molar ratio); 50 parts by weight of a pentaerythritol-based polyfunctional acrylate; methyl isobutyl ketone; 10 parts by weight of an acrylic polymer having a weight average molecular weight (Mw) of approximately 29,000, which was obtained by copolymerizing methyl methacrylate and acryloyl-modified glycerin methacrylate in a 71:29 (molar ratio); butyl acetate; 0.5 parts by weight of a photopolymerization initiator (manufactured by BASF, product name "Omnirad127D"); 15 parts by weight of a near-infrared absorber (cesium tungsten oxide dispersion, product name "YMF-02A", manufactured by Sumitomo Metal Mining Co., Ltd.); and ethyl acetate.

[0097] [Production Example 5] Gas-generating layer-forming composition E Composition E for forming a photothermal conversion layer was prepared in the same manner as in Production Example 4, except that the amount of "an acrylic polymer having a weight average molecular weight (Mw) of approximately 29,000, copolymerized with methyl methacrylate and acryloyl-modified glycerin methacrylate in a molar ratio of 71:29" was set to 40 parts by weight.

[0098] [Production Example 6] Gas generating layer forming composition F Composition F for forming a photothermal conversion layer was prepared by mixing 100 parts by weight of an acrylic polymer having a weight average molecular weight (Mw) of approximately 29,000, which was obtained by copolymerizing methyl methacrylate and acryloyl-modified glycerin methacrylate in a molar ratio of 71:29; butyl acetate; 0.5 parts by weight of a photopolymerization initiator (manufactured by BASF, product name "Omnirad127D"); 15 parts by weight of a near-infrared absorber (cesium tungsten oxide dispersion, product name "YMF-02A", manufactured by Sumitomo Metal Mining Co., Ltd.); and ethyl acetate.

[0099] [Production Example 7] Gas generating layer forming composition G Composition G for forming a gas generating layer was prepared in the same manner as in Production Example 1, except that the amount of infrared absorber (cesium tungsten oxide dispersion, product name "YMF-02A", manufactured by Sumitomo Metal Mining Co., Ltd.) was 4 parts by weight.

[0100] [Example 1] The gas-generating layer-forming composition A obtained in Production Example 1 was applied to one side of a polyimide film (manufactured by Toray DuPont, trade name "Kapton 100H", thickness: 25 μm) so that the thickness after solvent evaporation (drying) would be 2 μm, and then dried to form a gas-generating layer on the polyimide film. A polyethylene terephthalate film with a silicone release agent-treated surface (manufactured by Toray, trade name "Cerapeel", thickness: 38 μm) was laminated between rolls, and an integrated light intensity of 1380 mJ / cm was applied from the polyethylene terephthalate film with a silicone release agent-treated surface. 2 The film was irradiated with UV light under the following conditions: Thereafter, the polyethylene terephthalate film with the silicone release agent-treated surface was peeled off to obtain a laminate (gas generating layer / substrate (polyimide film)). An adhesive was applied to the substrate side of the laminate to form an adhesive layer with a thickness of 10 μm. An adhesive was also applied to the gas generating layer side of the laminate to form an adhesive layer with a thickness of 30 μm. The adhesive sheet thus obtained was subjected to the above evaluations. The results are shown in Tables 1 to 3. The adhesives for forming the substrate-side adhesive layer and the gas-generating layer-side adhesive layer were prepared as follows. Specifically, 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 the mixture was heated to 70°C to obtain an ethyl acetate solution of an acrylic polymer (Polymer A). Furthermore, 0.4 parts by weight of an epoxy-based crosslinking agent (manufactured by Mitsubishi Gas Chemical Company, Inc., product name "Tetrad C") was added to the ethyl acetate solution to obtain an adhesive for the gas-generating layer-side adhesive layer. Furthermore, 2 parts by weight of an epoxy-based crosslinking agent (manufactured by Mitsubishi Gas Chemical Company, Inc., product name "Tetrad C") was added to the above ethyl acetate solution to obtain an adhesive for the substrate-side adhesive layer. The pressure-sensitive adhesive layer on the gas-generating layer side had a light transmittance of 91.1% at a wavelength of 355 nm, a light transmittance of 92.8% at a wavelength of 600 nm, and a light transmittance of 93.91% at a wavelength of 1032 nm.

[0101] [Examples 2 to 4] A pressure-sensitive adhesive sheet was produced in the same manner as in Example 1, except that the thickness of the gas-generating layer was set as shown in Table 1. The pressure-sensitive adhesive sheet obtained was subjected to the above-mentioned evaluations. The results are shown in Table 1.

[0102] [Example 5] A pressure-sensitive adhesive sheet was produced in the same manner as in Example 1, except that gas-generating layer-forming composition B was used instead of gas-generating layer-forming composition A, and the thickness of the gas-generating layer was set to 5 μm. The resulting pressure-sensitive adhesive sheet was subjected to the above-mentioned evaluations. The results are shown in Table 1.

[0103] [Example 6] A pressure-sensitive adhesive sheet was produced in the same manner as in Example 1, except that gas-generating layer-forming composition C was used instead of gas-generating layer-forming composition A, and the thickness of the gas-generating layer was set to 20 μm. The resulting pressure-sensitive adhesive sheet was subjected to the above-mentioned evaluations. The results are shown in Table 1.

[0104] [Example 7] A pressure-sensitive adhesive sheet was produced in the same manner as in Example 1, except that a polyethylene terephthalate film (manufactured by Toray Industries, Inc., trade name "Lumirror S27", thickness: 38 μm) was used instead of a polyimide film (manufactured by Toray DuPont Co., Ltd., trade name "Kapton 100H", thickness: 25 μm) and the thickness of the gas generating layer was set to 5 μm. The resulting pressure-sensitive adhesive sheet was subjected to the above-mentioned evaluations. The results are shown in Table 2.

[0105] [Example 8] A pressure-sensitive adhesive sheet was produced in the same manner as in Example 7, except that gas-generating layer-forming composition D was used instead of gas-generating layer-forming composition A. The resulting pressure-sensitive adhesive sheet was subjected to the above-mentioned evaluations. The results are shown in Table 2.

[0106] [Example 9] A pressure-sensitive adhesive sheet was produced in the same manner as in Example 7, except that gas-generating layer-forming composition E was used instead of gas-generating layer-forming composition A. The resulting pressure-sensitive adhesive sheet was subjected to the above-mentioned evaluations. The results are shown in Table 2.

[0107] [Example 10] A pressure-sensitive adhesive sheet was produced in the same manner as in Example 7, except that gas-generating layer-forming composition F was used instead of gas-generating layer-forming composition A. The resulting pressure-sensitive adhesive sheet was subjected to the above-mentioned evaluations. The results are shown in Table 2.

[0108] [Example 11] A pressure-sensitive adhesive sheet was produced in the same manner as in Example 7, except that gas-generating layer-forming composition G was used instead of gas-generating layer-forming composition A. The resulting pressure-sensitive adhesive sheet was subjected to the above-mentioned evaluations. The results are shown in Table 2.

[0109] [Example 12] A pressure-sensitive adhesive sheet was produced in the same manner as in Example 1, except that a polyethylene naphthalate film (manufactured by Teijin Film Solutions Co., Ltd., product name "Teonex (registered trademark) Film Q51C-50", thickness: 50 μm) was used instead of a polyimide film (manufactured by Toray DuPont Co., Ltd., product name "Kapton 100H", thickness: 25 μm) and the thickness of the gas generating layer was set to 5 μm. The resulting pressure-sensitive adhesive sheet was subjected to the above-mentioned evaluations. The results are shown in Table 2.

[0110] [Example 13] A pressure-sensitive adhesive sheet was produced in the same manner as in Example 1, except that a polyether ether ketone film (manufactured by Kurabo Industries, Ltd., trade name "EXPEEK", thickness: 12 μm) was used instead of a polyimide film (manufactured by Toray DuPont Co., Ltd., trade name "Kapton 100H", thickness: 25 μm) and the thickness of the gas generating layer was set to 5 μm. The resulting pressure-sensitive adhesive sheet was subjected to the above-mentioned evaluations. The results are shown in Table 3.

[0111] [Comparative Example 1] A pressure-sensitive adhesive layer (10 μm and 30 μm thick) was formed on both sides of a polyimide film (manufactured by Toray DuPont Co., Ltd., product name "Kapton 100H", thickness: 25 μm) to obtain a pressure-sensitive adhesive sheet. The obtained pressure-sensitive adhesive sheet was subjected to the above-mentioned evaluations. The results are shown in Table 3.

[0112] Comparative Example 2 A pressure-sensitive adhesive layer (thickness: 10 μm, 30 μm) was formed on both sides of a polyethylene terephthalate film (manufactured by Toray Industries, Inc., trade name "Lumirror S27", thickness: 38 μm) to obtain a pressure-sensitive adhesive sheet. The obtained pressure-sensitive adhesive sheet was subjected to the above evaluations. The results are shown in Table 3.

[0113] Comparative Example 3 A resin composition was prepared in the same manner as in Production Example 1, except that a near-infrared absorbing agent (cesium tungsten oxide dispersion, trade name "YMF-02A", manufactured by Sumitomo Metal Mining Co., Ltd.) was not added. A laminate was obtained in the same manner as in Example 1, except that a resin layer having a thickness of 5 μm was formed using this resin composition instead of gas generating layer-forming composition A, and then a pressure-sensitive adhesive sheet was obtained. The pressure-sensitive adhesive sheet obtained was subjected to the above-mentioned evaluations. The results are shown in Table 3.

[0114] Comparative Example 4 Composition I for forming a gas-generating layer was prepared by mixing 100 parts by weight of black printing ink NB300 (manufactured by Dainichiseika Color & Chemicals Co., Ltd.) using carbon black and 5 parts by weight of an isocyanate-based curing agent (manufactured by Dainichiseika Color & Chemicals Co., Ltd., trade name "Lamic B Bardoner") Note that NB300 contains a polyurethane-based vinyl acetate-vinyl chloride copolymer as a binder resin, and an intensity peak thought to be urethane was confirmed by IR. Composition I for forming a gas generating layer was applied to one side of a polyethylene terephthalate film (manufactured by Toray Industries, Inc., product name "Lumirror S105", thickness: 25 μm) using a gravure coater so that the thickness after solvent evaporation (drying) would be 0.2 μm, and then dried to obtain a laminate (gas generating layer / substrate (polyethylene terephthalate film)). An adhesive was applied to the substrate side of the laminate to form an adhesive layer with a thickness of 10 μm. An adhesive was also applied to the gas generating layer side of the laminate to form an adhesive layer with a thickness of 30 μm. The resulting adhesive sheet was subjected to the above evaluations. The results are shown in Table 3. The composition of the adhesive was the same as in Example 1.

[0115] Comparative Example 5 Composition II for forming a gas-generating layer was prepared by mixing 100 parts by weight of CVL-PR (DIC Corporation), a black printing ink made from carbon black, with 4 parts by weight of an isocyanate-based curing agent (manufactured by DIC Corporation, trade name "CVL Hardener No. 10"). Note that CVL-PR contains a polyurethane-based vinyl acetate-vinyl chloride copolymer as a binder resin, and an intensity peak thought to be urethane was confirmed by IR. Composition II for forming a gas generating layer was applied to one side of a polyethylene terephthalate film (manufactured by Toray Industries, Inc., product name "Lumirror S105", thickness: 25 μm) using a gravure coater so that the thickness after solvent evaporation (drying) would be 3 μm, and then dried to obtain a laminate (gas generating layer / substrate (polyethylene terephthalate film)). An adhesive was applied to the substrate side of the laminate to form an adhesive layer with a thickness of 10 μm. An adhesive was also applied to the gas generating layer side of the laminate to form an adhesive layer with a thickness of 30 μm. The resulting adhesive sheet was subjected to the above evaluations. The results are shown in Table 3. The composition of the adhesive was the same as in Example 1.

[0116] [Table 1]

[0117] [Table 2]

[0118] [Table 3]

[0119] As is clear from Table 1, the pressure-sensitive adhesive sheet of the present invention has excellent visible light transmittance, and can also exhibit good releasability due to the effect of photothermal conversion. [Explanation of symbols]

[0120] 10 Base material 20 Gas generation layer 30 adhesive layer 40 Another adhesive layer 110 Adhesive sheet for temporary fixing of electronic components

Claims

1. a laminate structure A including a substrate and a gas generating layer disposed on at least one side of the substrate; a pressure-sensitive adhesive layer disposed on at least one side of the laminate structure A, The transmittance of light having a wavelength of 1032 nm is 75% or less, and The transmittance of light with a wavelength of 600 nm is 50% or more, the gas generating layer and / or the substrate are members that generate heat when irradiated with laser light, The gas generating layer is a resin layer that decomposes when heat is applied to generate gas. Adhesive sheet for temporarily fixing electronic components.

2. The pressure-sensitive adhesive sheet for temporarily fixing electronic components according to claim 1 , wherein the gas-generating layer is a layer capable of absorbing near-infrared rays.

3. The pressure-sensitive adhesive sheet for temporarily fixing electronic components according to claim 1 , wherein the gas-generating layer contains a near-infrared absorbing agent.

4. The pressure-sensitive adhesive sheet for temporarily fixing electronic components according to claim 3 , wherein the near-infrared absorbing agent is a substance containing elemental tungsten.

5. The pressure-sensitive adhesive sheet for temporarily fixing electronic components according to claim 3 , wherein the near-infrared absorbing agent is a substance containing elemental cesium.

6. The gas generating layer is a layer in which a near-infrared absorbing agent is contained in a resin, 2. The pressure-sensitive adhesive sheet for temporary fixing of electronic components according to claim 1, wherein the content of the near-infrared absorbing agent is 1 to 50 parts by weight per 100 parts by weight of the resin.

7. 2. The pressure-sensitive adhesive sheet for temporarily fixing electronic components according to claim 1, wherein the gas generation layer has a modulus of elasticity measured by a nanoindentation method of 100 MPa or more.

8. An adhesive sheet for temporarily fixing electronic components as described in claim 1, wherein the gas generating layer is composed of a cured product of a curable resin composition.

9. 2. The pressure-sensitive adhesive sheet for temporarily fixing electronic components according to claim 1, wherein the substrate is made of a polyimide resin, a polyester resin, or a polyether ether ketone resin.

10. A method for treating electronic components, comprising placing electronic components on the pressure-sensitive adhesive sheet according to claim 1 and then subjecting the electronic components to a predetermined treatment.

11. The method for processing an electronic component according to claim 10, wherein the processing is grinding, dicing, die bonding, wire bonding, etching, vapor deposition, chemical cleaning, molding, rewiring layer formation, through-hole formation, or device surface protection.

12. The pressure-sensitive adhesive sheet for temporary fixing of electronic components according to any one of claims 1 to 9 is placed on a support, An electronic component is placed on the pressure-sensitive adhesive sheet for temporarily fixing electronic components, and then and separating the substrate and the gas generating layer by irradiating the pressure-sensitive adhesive sheet with light. A method for separating a temporarily fixed electronic component from a support.

13. The method for separating a temporarily fixed electronic component from a support according to claim 12, wherein the light is laser light.

14. 14. The method for separating a temporarily fixed electronic component from a support according to claim 13, wherein the wavelength of the laser light is 800 nm or more.

15. 14. The method for separating a temporarily fixed electronic component from a support according to claim 13, wherein the wavelength of the laser light is 380 nm or less.

Images