Adhesive sheet for temporary fixing of electronic components

Abstract

To provide an adhesive sheet for temporarily fixing electronic components exhibiting detachability by light irradiation, the light to be irradiated having an enlarged range of choice.SOLUTION: The adhesive sheet for temporarily fixing electronic components of the present invention comprises a laminate structure A including a first photothermal conversion layer and a second photothermal conversion layer disposed on at least one side of the first photothermal conversion layer 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 355 nm of 50% or less.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an adhesive sheet for temporarily fixing electronic components. Background Art

[0002] In recent years, in order to improve the characteristics of semiconductor devices, the trend of fixing semiconductor chips and resin substrates after encapsulation to a rigid support substrate and performing high-temperature processes, mainly in fields such as semiconductor packaging, has been accelerating. For example, in an RDL formation process for forming circuits on a semiconductor package encapsulated with black resin, a method has been studied in which a workpiece is temporarily fixed flat on a light-transmitting substrate such as glass, RDL is formed on the workpiece, and then the rigid substrate is separated. In such applications, liquid adhesives containing carbon black powder as a photothermal conversion material are widely used. In the technology using a photothermal conversion material, the photothermal conversion material is applied onto a light-transmitting substrate to form a photothermal conversion layer, which firmly fixes the workpiece during processing; when peeling, irradiation with laser light of a predetermined wavelength causes the photothermal conversion layer to absorb the light, convert it into heat, and undergo thermal decomposition, so that the workpiece and the light-transmitting substrate can be easily separated. However, for liquid adhesives for photothermal conversion, it is necessary to change the wavelength of the irradiated laser light depending on the photothermal conversion material, which poses a problem of complicating the manufacturing process. Prior Art Documents Patent Documents

[0003] Patent Document 1 Japanese Patent No. 4565804 Patent Document 2 Japanese Patent No. 4405246 Patent Document 3 Japanese Patent No. 6980999 Summary of the Invention Problem to be Solved by the Invention

[0004] The present invention was made to solve the above problems, and its objective is to provide an adhesive sheet for temporarily fixing electronic components that exhibits peelability upon light irradiation, and which allows for a wide range of selection of the light used for irradiation. [Means for solving the problem]

[0005] The adhesive sheet for temporarily fixing electronic components of the present invention comprises a laminated structure A having a first photothermal conversion layer and a second photothermal conversion layer disposed on at least one side of the first photothermal conversion layer, and an adhesive layer disposed on at least one side of the laminated structure A, wherein the transmittance of light with a wavelength of 1032 nm is 75% or less and the transmittance of light with a wavelength of 355 nm is 50% or less. In one embodiment, the first photothermal conversion layer is a layer capable of absorbing ultraviolet light. In one embodiment, the first photothermal conversion layer is made of a polyimide resin, a polyester resin, or a polyetheretherketone resin. In one embodiment, the temperature at which the first photothermal conversion layer loses 5% of its weight is 300°C or higher. In one embodiment, the second photothermal conversion layer is a layer capable of absorbing near-infrared rays. In one embodiment, the second photothermal conversion layer includes a near-infrared absorbent. In one embodiment, the near-infrared absorber is a substance containing the element tungsten. In one embodiment, the near-infrared absorber is a substance containing cesium. In one embodiment, the 5% weight loss temperature of the second photothermal conversion layer is 300°C or higher. According to another aspect of the present invention, a method for processing electronic components is provided. In this processing method, after placing the electronic components on the adhesive sheet, a predetermined processing is performed on the electronic components. In one embodiment, the above process is grinding, dicing, die bonding, wire bonding, etching, vapor deposition, chemical cleaning, molding, redistribution layer formation, through-hole formation, or protection of the device surface. A method for separating a temporarily fixed electronic component from a support is provided. This separation method includes placing an adhesive sheet for temporarily fixing the electronic component on the support, placing the electronic component on the adhesive sheet for temporarily fixing the electronic component, and then irradiating the adhesive sheet with light to separate the first photothermal conversion layer and the second photothermal conversion layer. In one embodiment, the light is laser light. In one embodiment, the wavelength of the laser light is 800 nm or greater. 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 an adhesive sheet for temporarily fixing electronic components that exhibits peelability upon light irradiation, and which allows for a wide range of selection of the light used for irradiation. [Brief explanation of the drawing]

[0007] [Figure 1] This is a schematic cross-sectional view of an adhesive sheet for temporarily fixing electronic components according to one embodiment of the present invention. [Figure 2] This figure illustrates a method for using an adhesive sheet for temporarily fixing electronic components in one embodiment of the present invention. [Figure 3] This figure illustrates a method for using an adhesive sheet for temporarily fixing electronic components in one embodiment of the present invention. [Modes for carrying out the invention]

[0008] A. Overview of adhesive sheets for temporary fixing of electronic components Figure 1 is a schematic cross-sectional view of an adhesive sheet for temporarily fixing electronic components according to one embodiment of the present invention. The adhesive sheet for temporarily fixing electronic components 110 comprises a laminated structure A comprising a first photothermal conversion layer 10 and a second photothermal conversion layer 20 disposed on at least one side of the first photothermal conversion layer 10, and an adhesive layer 30 disposed on at least one side of the laminated structure A. The photothermal conversion layer is a layer that absorbs light of a predetermined wavelength and converts the light into heat. Due to the heat generated by the photothermal conversion layer, the photothermal conversion layer itself decomposes, or a layer adjacent to the photothermal conversion layer undergoes thermal decomposition. As a result, the adhesive sheet for temporarily fixing electronic components exhibits peelability. In one embodiment, due to the heat generated by the first or second photothermal conversion layer, the second photothermal conversion layer undergoes thermal decomposition and generates gas, the surface shape of the second photothermal conversion layer changes, and the first and second photothermal conversion layers can be easily separated (peeled off). In this specification, "thermal decomposition" means that a weight reduction of 5% or more may occur when heated to 250°C or higher. The adhesive sheet for temporary fixing of electronic components may further comprise other layers as long as the effects of the present invention are obtained. For example, the adhesive sheet 110 may further comprise another adhesive layer 40 disposed on the side of the first photothermal conversion layer 10 of the laminated structure A. Hereinafter, the adhesive sheet for temporary fixing of electronic components may be simply referred to as the adhesive sheet.

[0009] In one embodiment, the first photothermal conversion layer and the second photothermal conversion layer are arranged directly. When the first and second photothermal conversion layers are arranged directly, when heat is generated in the first photothermal conversion layer, that heat is preferably propagated to the second photothermal conversion layer, and gas generation preferably occurs. "Arranged directly" means that there are no other layers arranged between the first and second photothermal conversion layers, and these layers are in contact with each other.

[0010] The above adhesive sheet for temporarily fixing electronic components has a transmittance of 75% or less for light with a wavelength of 1032 nm. Furthermore, the above adhesive sheet for temporarily fixing electronic components has a transmittance of 50% or more for light with a wavelength of 600 nm. The transmittance for 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 for light with a wavelength of 1032 nm is, for example, 1% (preferably 0.5%). The transmittance for light with a wavelength of 600 nm is more preferably 60% or more, even more preferably 70% or more, and particularly preferably 80% or more. The upper limit of the transmittance for light with a wavelength of 600 nm is, for example, 90% (preferably 95%). The above adhesive sheet for temporarily fixing electronic components is advantageous not only in its ability to absorb laser light and exhibit peelability, but also in its excellent visibility through the adhesive sheet.

[0011] The transmittance of the above-mentioned adhesive sheet for temporary fixing of electronic components to light at a wavelength of 355 nm is 50% or less. By adjusting the transmittance of the first photothermal conversion layer to light at 355 nm, and setting the transmittance of the adhesive sheet for temporary fixing of electronic components to this range, it becomes possible to generate heat in the first photothermal conversion layer using UV laser light, and to obtain an adhesive sheet for temporary fixing of electronic components that also exhibits peelability using UV laser light. The transmittance of the above-mentioned adhesive sheet for temporary fixing of electronic components to light at a wavelength of 355 nm is more preferably 0% to 30%, and even more preferably 0% to 20%. Within this range, the effects of the present invention become remarkable.

[0012] In one embodiment, a method is provided for separating a temporarily fixed electronic component from a support, which includes placing an adhesive sheet for temporarily fixing the electronic component on a support, placing the electronic component on the adhesive sheet for temporarily fixing the electronic component, and then irradiating the photothermal conversion layer (first photothermal conversion layer or second photothermal conversion layer) with light to separate the first photothermal conversion layer and the second photothermal conversion layer. More specifically, the method is as follows. In one embodiment, the adhesive sheet for temporarily fixing the electronic component is attached to a support via an adhesive layer, and is used with the electronic component (e.g., a semiconductor component such as a semiconductor wafer) placed on the first photothermal conversion layer side. In one embodiment, the adhesive sheet may behave as shown in Figure 2 and below. The adhesive sheet 110 shown in Figure 2 comprises a laminated structure A (first photothermal conversion layer / second photothermal conversion layer) and an adhesive layer 30 disposed on the second photothermal conversion layer 20 side of the laminated structure A. In this embodiment, a second photothermal conversion layer capable of absorbing infrared rays is used, and this second photothermal conversion layer performs a photothermal conversion function. (1) The adhesive sheet 110 is placed on the support 200 such that the adhesive layer 30 side faces the support 200, and the electronic component 300 to be processed is placed on the side of the adhesive sheet 110 opposite to the support 200 (Figure 2(a)). The electronic component 300 can be attached to the adhesive sheet 110, for example, via another adhesive layer 40. (2) By irradiating the adhesive sheet 110 (essentially the second photothermal conversion layer) placed on the support 200 with IR laser light (for example, wavelength of 800 nm or more) from the support 200 side, the second photothermal conversion layer 20 generates heat, and the second photothermal conversion layer 20 thermally decomposes and generates gas (Figure 2(b)). (3) As a result, the surface shape of the second photothermal conversion layer 20 changes, and the second photothermal conversion layer 20 exhibits peelability from the first photothermal conversion layer 10. This makes it possible to peel the first photothermal conversion layer 10 (first photothermal conversion layer 10 with electronic component 300) from the support 200 (Figure 2(c)). As a result, the electronic component 300 can be separated from the support 200. (4) Next, peeling the laminated structure consisting of the pressure-sensitive adhesive layer 30 / the second photothermal conversion layer 20 on the support 200 allows recovery of the clean support 200 with suppressed residue (Fig. 2(d)).

[0013] In another embodiment, the pressure-sensitive adhesive sheet may behave as shown in FIG. 3 and described below. The pressure-sensitive adhesive sheet 110 shown in FIG. 3 includes a laminated structure A (a first photothermal conversion layer / a second photothermal conversion layer) and a pressure-sensitive adhesive layer 30 disposed on the second photothermal conversion layer 20 side of the laminated structure A. In this embodiment, the first photothermal conversion layer capable of absorbing ultraviolet light is used, and the first photothermal conversion layer exerts a photothermal conversion function. (1) The pressure-sensitive adhesive sheet 110 is disposed on the support 200 such that the pressure-sensitive adhesive layer 30 side faces the support 200 side, and an electronic component 300, which is a workpiece, is further disposed on the opposite side of the pressure-sensitive adhesive sheet 110 from the support 200 (Fig. 3(a)). The electronic component 300 may be attached to the pressure-sensitive adhesive sheet 110, for example, via another pressure-sensitive adhesive layer 40. (2) Irradiating the pressure-sensitive adhesive sheet 110 (substantially, the first photothermal conversion layer) disposed on the support 200 with UV laser light (for example, wavelength of 380 nm or less) from the support 200 side causes the first photothermal conversion layer 10 to generate heat, whereby the second photothermal conversion layer 20 is thermally decomposed and generates gas (Fig. 3(b)). (3) As a result, the surface shape of the second photothermal conversion layer 20 changes, and the second photothermal conversion layer 20 exhibits releasability from the first photothermal conversion layer 10. This enables peeling of the first photothermal conversion layer 10 (the first photothermal conversion layer 10 with the 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, peeling the laminated structure consisting of the pressure-sensitive adhesive layer 30 / the second photothermal conversion layer 20 on the support 200 allows recovery of the clean support 200 with suppressed residue (Fig. 3(d)).

[0014] An adhesive sheet having the above characteristics can be obtained, for example, by incorporating a suitable near-infrared absorber in a second photothermal conversion layer formed from resin, and by using a UV light-absorbing material as the material constituting the first photothermal conversion layer.

[0015] According to the present invention, by forming two types of photothermal conversion layers and configuring them so that the transmittance of light with a wavelength of 1032 nm is 75% or less and the transmittance of light with a wavelength of 355 nm is 50% or less, it is possible to obtain an adhesive sheet for temporary fixing of electronic components that can be peeled off by either infrared or ultraviolet light, and has a wide range of selectable light sources.

[0016] The adhesive strength of the above adhesive sheet at 23°C, when the adhesive layer is attached to PET, is preferably 0.2 N / 20 mm to 10 N / 20 mm, and more preferably 3 N / 20 mm to 8 N / 20 mm. Within this range, an adhesive sheet suitable for temporary fixing applications can be obtained without positional displacement on the support. The adhesive strength is measured in accordance with JIS Z 0237:2000. Specifically, the pyrolysis layer is attached to a glass plate (arithmetic mean surface roughness Ra: 10 ± 8 nm) by one back-and-forth motion of a 2 kg roller, and then the adhesive sheet is peeled off under conditions of a peeling angle of 180° and a peeling speed (tensile speed) of 300 mm / min to measure the adhesive strength.

[0017] The adhesive strength of the adhesive sheet at 23°C when the 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. Within this range, an adhesive sheet suitable for temporary fixing applications can be obtained without positional displacement on the support.

[0018] The thickness of the adhesive sheet for temporarily fixing the electronic components is preferably 10 μm to 500 μm, and more preferably 20 μm to 400 μm.

[0019] B. First photothermal conversion layer In one embodiment, the first photothermal conversion layer can also function as a substrate in an adhesive sheet.

[0020] In one embodiment, the first photothermal conversion layer is a layer capable of absorbing ultraviolet light.

[0021] The first photothermal conversion layer can be composed of any suitable resin, as long as the effects of the present invention are obtained. Preferably, the first photothermal conversion layer is composed of a polyimide resin, a polyester resin, or a polyetheretherketone resin. Among these, polyimide resins are particularly preferred. These resins have UV absorption properties, and by using such resins, an adhesive sheet that exhibits peelability when exposed to UV laser light can be obtained.

[0022] The thickness of the first photothermal conversion layer is preferably 2 μm to 300 μm, more preferably 2 μm to 100 μm, and even more preferably 2 μm to 50 μm.

[0023] In one embodiment, the transmittance of the first photothermal conversion layer to light at a wavelength of 1032 nm is 60% to 95%, preferably 70% to 90%.

[0024] In one embodiment, the transmittance of the first photothermal conversion layer to light 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 first photothermal conversion layer to light at a wavelength of 600 nm is, for example, 95% (preferably 99%).

[0025] In one embodiment, the transmittance of the first photothermal conversion layer to light at a wavelength of 355 nm is preferably 50% or less, and more preferably 0% to 20%. Within this range, an adhesive sheet that can exhibit peelability with UV laser light can be obtained.

[0026] The tensile modulus of the first photothermal conversion layer 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 this range, the gas generated by laser irradiation is preferably blocked by the first photothermal conversion layer, and peelability due to the change in the shape of the surface of the second photothermal conversion layer is preferably exhibited. The tensile modulus can be measured using a dynamic viscoelasticity measuring device. The specific measurement method will be described later.

[0027] The 5% weight loss temperature of the first photothermal conversion layer 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, an adhesive sheet with excellent heat resistance can be obtained. In addition, since the RDL formation process is generally carried out at a temperature of 250°C or lower, if the 5% weight loss temperature is within the above range, outgassing from the first photothermal conversion layer (substrate) during the RDL formation process will be reduced, reducing the impact on electronic components and enabling a stable process. Furthermore, if the 5% weight loss temperature of the first photothermal conversion layer (substrate) is within the above range, it will be less susceptible to damage during laser irradiation, and the tape (adhesive layer / substrate) can be removed from electronic components without breaking when peeling it off. The 5% weight loss temperature refers to the temperature at which the weight of the sample to be evaluated decreases by 5% by weight compared to the dry weight of the sample before heating, when the sample is heated. The 5% weight loss temperature is measured using a differential thermal analyzer under the following conditions: heating temperature of 10°C / min, nitrogen atmosphere, and flow rate of 25 ml / min. The dry weight of the sample refers to the weight after removing the water content from the sample.

[0028] C. Second photothermal conversion layer In one embodiment, the second photothermal conversion layer is a layer that can be heated and thermally decomposed to generate gas. The heat that is applied may be due to the heat generated by the second photothermal conversion layer or to the heat generated by the first photothermal conversion layer.

[0029] In one embodiment, the second photothermal conversion layer is a layer capable of absorbing near-infrared light. More specifically, the transmittance of the second photothermal conversion 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 this range, a second photothermal conversion layer that readily absorbs IR laser light and generates heat can be formed. The lower limit of the transmittance of the second photothermal conversion layer at a wavelength of 1032 nm is, for example, 5% (preferably 1%).

[0030] In one embodiment, the transmittance of the second photothermal conversion layer 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. Within this range, a second photothermal conversion layer that can contribute to improved visibility can be formed. The upper limit of the transmittance of the second photothermal conversion layer at a wavelength of 600 nm is, for example, 90% (preferably 95%).

[0031] In one embodiment, the transmittance of the second photothermal conversion layer at a wavelength of 355 nm is preferably 40% or more, and more preferably 50% to 95%. Within this range, an adhesive sheet can be obtained that exhibits peelability even with UV laser light, by appropriately selecting the first photothermal conversion layer capable of absorbing ultraviolet light.

[0032] The thickness of the second photothermal conversion 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.

[0033] The 5% weight loss temperature of the second photothermal conversion 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, an 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, if the 5% weight loss temperature is within the above range, outgassing from the second photothermal conversion layer during the RDL formation process will be reduced, mitigating the impact on electronic components and enabling a stable process.

[0034] The elastic modulus of the second photothermal conversion layer obtained 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, a change in the shape of the second photothermal conversion layer due to gas generation occurs favorably when irradiated with laser light, and excellent peelability can be achieved. The elastic modulus obtained by nanoindentation refers to the elastic modulus obtained from the load-indentation depth curve obtained by continuously measuring the load applied to the indenter and the indentation depth during loading and unloading when the indenter is pressed into the sample. The elastic modulus obtained by nanoindentation is obtained by numerically processing the displacement-load hysteresis curve obtained by pressing a diamond Berkovich-type (triangular pyramidal) probe perpendicularly against the surface of the layer to be measured using software (triboscan) attached to the measuring device. In this specification, the elastic modulus obtained by the nanoindentation method is the elastic modulus measured using a nanoindenter (Triboindenter TI-950, manufactured by Hysitron Inc.) at a predetermined temperature (25°C) using a single indentation method, 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 second photothermal conversion 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.

[0035] In one embodiment, the second photothermal conversion layer includes a near-infrared absorbent. In one embodiment, the second photothermal conversion layer may be a layer in which the near-infrared absorbent is contained in a resin. The second photothermal conversion layer may be a resin film. The resin film may be, for example, a film in which the near-infrared absorbent is contained in a resin (e.g., a single-layer film), or a film consisting of a layer containing a predetermined near-infrared absorbent (e.g., a printed layer) and a resin layer.

[0036] As the near-infrared absorbent described above, any suitable near-infrared absorbent can be used in any suitable amount, as long as it can impart near-infrared absorption and the effects of the present invention can be obtained. Examples of such near-infrared absorbents include tungsten cesium oxide, lanthanum hexaboride, tin-doped indium oxide, antimond-doped tin oxide, cyanine compounds, phthalocyanine compounds, dithiol metal complexes, naphthoquinone compounds, diimmonium compounds, azo compounds, etc. Among these, tungsten cesium oxide or lanthanum hexaboride is preferred, and tungsten cesium oxide is more preferred. By using such a near-infrared absorbent, a second photothermal conversion layer can be formed that is capable of absorbing near-infrared rays and generating heat, while also having excellent visible light transmittance.

[0037] Preferably, a substance containing tungsten is used as the near-infrared absorber. For example, tungsten cesium oxide is a preferred substance containing tungsten.

[0038] Preferably, a substance containing cesium is used as the near-infrared absorber. For example, tungsten cesium oxide is a preferred substance containing cesium.

[0039] When the second photothermal conversion layer contains a resin and a near-infrared absorbent, the content ratio of the near-infrared absorbent 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, per 100 parts by weight of the resin. Within this range, a second photothermal conversion layer capable of favorably absorbing IR laser light can be formed.

[0040] Any suitable resin can be used as the resin constituting the second photothermal conversion layer. Examples of resins constituting the second photothermal conversion layer include acrylic resins, epoxy resins, polyester resins, polystyrene resins, polyimide resins, polyurethane resins, and the like. Among these, acrylic resins are preferred.

[0041] Preferably, the second photothermal conversion layer is composed of a cured product of a curable (e.g., active energy ray curable or thermosetting) resin composition, more preferably a cured product of an active energy ray curable resin composition, and more preferably a cured product of an acrylic active energy ray curable resin composition. The second photothermal conversion layer formed from a cured product of a curable resin composition is advantageous in that it has excellent heat resistance. In one embodiment, the second photothermal conversion layer, which is composed as a cured product of a curable resin composition, includes a polymerization initiator. The polymerization initiator is, for example, a photopolymerization initiator or a thermal polymerization initiator. The near-infrared absorber may be included in the curable resin composition. In one embodiment, the curable resin composition includes a pentaerythritol-based polyfunctional (meth)acrylate. By using a pentaerythritol-based polyfunctional (meth)acrylate, a second photothermal conversion layer with excellent heat resistance can be formed.

[0042] In one embodiment, the active energy ray curable resin composition used is an active energy ray curable resin composition (A1) comprising a base polymer (or a monomer or oligomer constituting the base polymer) and an active energy ray reactive compound (monomer or oligomer). In another embodiment, an active energy ray curable resin composition (A2) is used, comprising an active energy ray reactive polymer as the base polymer. In one embodiment, the base polymer has a functional group that can be cleaved by a photopolymerization initiator. Examples of such functional groups include a functional group 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 streams, ionization rays, particle beams, etc. Preferably, ultraviolet rays are used.

[0043] Examples of base polymers used in the above resin composition (A1) include rubber-based polymers such as natural rubber, polyisobutylene rubber, styrene-butadiene rubber, styrene-isoprene-styrene block copolymer rubber, recycled rubber, butyl rubber, polyisobutylene rubber, and nitrile rubber (NBR); silicone-based polymers; and acrylic-based polymers. These polymers may be used individually or in combination of two or more. Among these, acrylic-based polymers are preferred.

[0044] Examples of acrylic polymers include monopolymers or copolymers of (meth)acrylic acid esters such as alkyl (meth)acrylates, cycloalkyl (meth)acrylates, and aryl (meth)acrylates; and copolymers of the (meth)acrylic acid ester with other copolymerizable monomers. Specific examples of alkyl (meth)acrylates 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) Examples of C1-20 alkyl esters of (meth)acrylate 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, alkyl esters of (meth)acrylate having a linear or branched alkyl group with 4 to 18 carbon atoms are preferably used.

[0045] Other copolymerizable monomers include, for example, 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 functional group-containing monomers such as acrylonitrile. Examples of 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 acid anhydride monomers include maleic anhydride and itaconic anhydride. Examples of 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 styrene sulfonic acid, allyl sulfonic acid, 2-(meth)acrylamide-2-methylpropanesulfonic acid, (meth)acrylamidepropanesulfonic acid, sulfopropyl (meth)acrylate, and (meth)acryloyloxynaphthalenesulfonic acid. An example of a phosphate group-containing monomer is 2-hydroxyethyl acryloyl phosphate. An example of an acrylamide is N-acryloylmorpholine. These may be used individually or in combination of two or more. The content ratio of the constituent units derived from the above copolymerizable monomers is preferably 60 parts by weight or less, and more preferably 40 parts by weight or less, per 100 parts by weight of the base polymer (acrylic polymer).

[0046] In one embodiment, an acrylic monomer having a glass transition temperature of 40°C or higher when used as a homopolymer is used as the monomer constituting the acrylic polymer. That is, the acrylic polymer contains constituent units derived from an acrylic monomer having a glass transition temperature of 40°C or higher when used as a homopolymer. Examples of such acrylic monomers include methyl methacrylate, glycidyl methacrylate, isobutyl methacrylate, acrylonitrile, methacrylonitrile, isopropylacrylamide, acryloylmorpholine, and isobornyl acrylate. Methyl methacrylate is preferred among these. By using an acrylic polymer containing constituent units derived from such monomers, stickiness caused by decomposition products due to laser irradiation can be prevented. The content ratio of constituent units derived from an acrylic monomer having a glass transition temperature of 40°C or higher when used as a homopolymer is preferably 30 to 80 parts by weight, and more preferably 40 to 75 parts by weight, per 100 parts by weight of the base polymer (acrylic polymer). Within this range, the above effect is significant.

[0047] Acrylic polymers may contain structural units derived from polyfunctional monomers. By using polyfunctional monomers, a second photothermal conversion layer with excellent heat resistance can be formed. 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 individually or in combination of two or more. When the polymer contains structural units derived from polyfunctional monomers, the content of these structural units is preferably 30 parts by weight or more, and more preferably 40 parts by weight or more, per 100 parts by weight of the base polymer (acrylic polymer). The upper limit of the content of these structural units derived from polyfunctional monomers is preferably 400 parts by weight or less, and more preferably 300 parts by weight or less, per 100 parts by weight of the base polymer (acrylic polymer).

[0048] The weight-average molecular weight of the above acrylic polymer is preferably 10,000 to 1,500,000, and more preferably 20,000 to 1,000,000. The weight-average molecular weight can be measured by GPC (solvent: THF).

[0049] Examples of the active energy ray-reactive compounds that can be used in the above resin composition (A1) include photoreactive monomers or oligomers having a functional group with polymerizable carbon-carbon multiple bonds, 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 with 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, polyethylene glycol di(meth)acrylate; polyfunctional urethane (meth)acrylate; epoxy (meth)acrylate; and oligoester (meth)acrylate. In addition, monomers such as methacryloisocyanate, 2-methacryloyloxyethyl isocyanate (2-isocyanatoethyl methacrylate), and m-isopropenyl-α,α-dimethylbenzyl isocyanate may also be used. Specific examples of photoreactive oligomers include dimers to pentamers of the above-mentioned monomers. The molecular weight of the photoreactive oligomer is preferably 100 to 3000.

[0050] In one embodiment, the active energy ray-curable resin composition (A1) includes 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 its polymer with (meth)acrylate. By using a pentaerythritol-based polyfunctional (meth)acrylate as the active energy ray-reactive compound, a second photothermal conversion layer with excellent heat resistance can be formed.

[0051] Furthermore, monomers such as epoxidized butadiene, glycidyl methacrylate, acrylamide, and vinylsiloxane, or oligomers composed of such monomers, may be used as the active energy ray-reactive compound.

[0052] In the above 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, per 100 parts by weight of the base polymer.

[0053] Examples of active energy ray-reactive polymers (base polymers) included in the above resin composition (A2) include polymers having functional groups with carbon-carbon multiple bonds, such as acryloyl groups, methacryloyl groups, vinyl groups, allyl groups, and acetylene groups. Specific examples of active energy ray-reactive polymers include polymers composed of polyfunctional (meth)acrylates (e.g., polymers containing structural units derived from polyfunctional monomers); photocationic polymers; cinnamoyl group-containing polymers such as polyvinyl cinnamate; diazotized amino novolac resins; polyacrylamides; and the like.

[0054] In one embodiment, an active energy ray reactive polymer is used, which is constructed by introducing an active energy ray polymerizable carbon-carbon double bond into the side chains, main chain, and / or main chain terminals of the above-mentioned acrylic polymer. As a method for introducing a radiation-polymerizable carbon-carbon double bond into an acrylic polymer, for example, an acrylic polymer is obtained by copolymerizing raw material monomers containing a monomer having a predetermined functional group (first functional group), and then a compound having a predetermined functional group (second functional group) that can react and bond with the first functional group and a radiation-polymerizable carbon-carbon double bond is subjected to a condensation or addition reaction with the acrylic polymer while maintaining the radiation polymerizability of the carbon-carbon double bond.

[0055] Examples of combinations of the first and second functional groups include carboxyl group and epoxy group, epoxy group and carboxyl group, carboxyl group and aziridyl group, aziridyl group and carboxyl group, hydroxyl group and isocyanate group, and isocyanate group and hydroxyl group. Of these combinations, from the viewpoint of ease of reaction tracking, the combination of hydroxyl group and isocyanate group, or the combination of isocyanate group and hydroxyl group is preferred. Furthermore, since it is technically difficult to produce polymers having highly reactive isocyanate groups, from the viewpoint of ease of production or availability of acrylic polymers, it is more preferable that the first functional group on the acrylic polymer side is a hydroxyl group and the second functional group is 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, as the acrylic polymer having the first functional group, it is preferable that it contains structural units derived from the above-mentioned hydroxyl group-containing monomer, and it is also preferable that it contains structural units derived from ether compounds such as 2-hydroxyethyl vinyl ether, 4-hydroxybutyl vinyl ether, and diethylene glycol monovinyl ether.

[0056] The above resin composition (A2) may further contain the above-mentioned active energy ray-reactive compound (monomer or oligomer).

[0057] In one embodiment, the active energy ray curable resin composition contains a polymerization initiator. Examples of polymerization initiators include photopolymerization initiators and thermal polymerization initiators, with photopolymerization initiators being preferred.

[0058] Any suitable initiator can be used as a photopolymerization initiator. Examples of photopolymerization initiators 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 benzyldimethyl ketal. Examples 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 photopolymerization initiator used can be set to any appropriate amount.

[0059] In one embodiment, the active energy ray curable resin composition may include a photosensitizer.

[0060] Preferably, the above-mentioned active energy ray curable resin composition contains a crosslinking agent. Examples of crosslinking agents include isocyanate-based crosslinking agents, epoxy-based crosslinking agents, oxazoline-based crosslinking agents, aziridine-based crosslinking agents, melamine-based crosslinking agents, peroxide-based crosslinking agents, urea-based crosslinking agents, metal alkoxide-based crosslinking agents, metal chelate-based crosslinking agents, metal salt-based crosslinking agents, carbodiimide-based crosslinking agents, amine-based crosslinking agents, and the like.

[0061] The content ratio of the above crosslinking agent is preferably 0.01 to 20 parts by weight per 100 parts by weight of the base polymer of the resin composition.

[0062] In one embodiment, an epoxy crosslinking agent is preferably used. Using an epoxy crosslinking agent allows for the formation of a thermal decomposition layer with a high 5% weight loss temperature after UV irradiation. Examples of the epoxy crosslinking agent include N,N,N',N'-tetraglycidyl-m-xylenediline, diglycidylaniline, 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 "Epolite 1600"), neopentyl glycol diglycidyl ether (manufactured by Kyoeisha Chemical Co., Ltd., trade name "Epolite 1500NP"), and ethylene glycol. Recall diglycidyl ether (manufactured by Kyoeisha Chemical Co., Ltd., product name "Epolite 40E"), propylene glycol diglycidyl ether (manufactured by Kyoeisha Chemical Co., Ltd., product name "Epolite 70P"), polyethylene glycol diglycidyl ether (manufactured by Nippon Oil & Fats Co., Ltd., product name "Epiol E-400"), polypropylene glycol diglycidyl ether (manufactured by Nippon Oil & Fats Co., Ltd., product name "Epiol P-200"), sorbitol polyglycidyl ether (manufactured by Nagase ChemteX Corporation, product name "Denacol") Examples include "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 adipic acid ester, diglycidyl o-phthalate 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 parts by weight to 10 parts by weight, more preferably 0.05 parts by weight to 7 parts by weight, per 100 parts by weight of the base polymer.

[0063] In one embodiment, an isocyanate-based crosslinking agent is preferably used. Specific examples of the above-mentioned isocyanate-based crosslinking agents 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; 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 derivative of hexamethylene diisocyanate (manufactured by Nippon Polyurethane Industry Co., Ltd., trade name "Coronate HX"); and the like. 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, and more preferably 0.5 to 10 parts by weight, per 100 parts by weight of the base polymer.

[0064] Active energy ray curable resin compositions may further contain any suitable additives as needed. Examples of additives include active energy ray polymerization accelerators, radical scavengers, tackifiers, plasticizers (e.g., trimellitic acid ester plasticizers, pyromellitic acid ester plasticizers, etc.), pigments, dyes, fillers, antioxidants, conductive materials, antistatic agents, ultraviolet absorbers, light stabilizers, release modifiers, softeners, surfactants, flame retardants, antioxidants, and the like.

[0065] (Method for forming a photothermal conversion layer) The above-mentioned photothermal conversion layer can be manufactured by any suitable method. The method for forming the above-mentioned photothermal conversion layer includes, for example, a step (A) of preparing a second photothermal conversion layer forming composition, a step (B) of coating the first photothermal conversion layer with the second photothermal conversion layer forming composition, and a step (C) of curing the coating layer of the second photothermal conversion layer forming composition.

[0066] The second photothermal conversion layer forming composition contains a near-infrared absorbent. In one embodiment, the second photothermal conversion layer forming composition may be the curable resin composition (preferably the active energy ray curable resin composition) containing the near-infrared absorbent. In one embodiment, the near-infrared absorbent may be a substance containing tungsten and / or a substance containing cesium. That is, in one embodiment, the second photothermal conversion layer forming composition contains a substance containing tungsten and / or a substance containing cesium.

[0067] Any suitable method can be used to coat the second photothermal conversion layer-forming composition. Examples of coating methods for the second photothermal conversion layer-forming composition include bar coater coating, air knife coating, gravure coating, gravure reverse coating, reverse roll coating, lip coating, die coating, dip coating, offset printing, flexographic printing, screen printing, and the like.

[0068] If the second photothermal conversion layer forming composition contains an active energy ray reactive compound, in step (C), the coating layer of the second photothermal conversion layer forming composition is irradiated with active energy rays such as ultraviolet light. The irradiation conditions can be any appropriate conditions depending on the composition of the second photothermal conversion layer forming composition.

[0069] If the second photothermal conversion layer forming composition is thermosetting, a heat treatment is performed in step (C). The heating conditions can be any appropriate conditions depending on the composition of the second photothermal conversion layer forming composition.

[0070] D. Laminated structure A (First photothermal conversion layer / Second photothermal conversion layer) The transmittance of light at a wavelength of 1032 nm in the laminated structure A comprising a first photothermal conversion layer and a second photothermal conversion layer is preferably 75% or less, more preferably 65% ​​or less, even more preferably 50% or less, even more preferably 40% or less, particularly preferably 30% or less, and most preferably 20% or less. Within this range, an adhesive sheet that can preferably absorb IR laser light can be obtained.

[0071] The transmittance of light at a wavelength of 600 nm through the above-described laminated structure A 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 of light at a wavelength of 600 nm is, for example, 90% (preferably 95%). An adhesive sheet having such a laminated 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.

[0072] In one embodiment, the transmittance of 355 nm light in the laminated 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 355 nm light in the first photothermal conversion layer and setting the transmittance of 355 nm light in the laminated structure A to this range, it becomes possible to generate heat in the first photothermal conversion layer using UV laser light, and to obtain an adhesive sheet that can also exhibit peelability using UV laser light.

[0073] The thickness of the above-mentioned laminated structure A is preferably 10 μm to 200 μm, and more preferably 20 μm to 150 μm.

[0074] E. Adhesive layer The adhesive layer described above contains any suitable adhesive. For example, it may contain a pressure-sensitive adhesive or a curable adhesive. As the curable adhesive, the active energy ray curable resin composition described above may be used. The adhesive layer can be formed by coating the laminated structure A (first photothermal conversion layer / second photothermal conversion layer) with the adhesive by any suitable method.

[0075] Examples of the above-mentioned adhesives include acrylic adhesives, silicone adhesives, epoxy adhesives, styrene-based thermoplastic elastomers, and ester-based adhesives. In one embodiment, an acrylic adhesive is used. An example of an acrylic adhesive is described below.

[0076] (Base polymer) Examples of the above acrylic adhesives include acrylic adhesives that use an acrylic polymer (homopolymer or copolymer) as a base polymer, which uses one or more alkyl (meth)acrylate esters as monomer components. Specific examples of alkyl (meth)acrylate 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) Examples of C1-20 alkyl esters of (meth)acrylate 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, alkyl esters of (meth)acrylate having a linear or branched alkyl group with 4 to 18 carbon atoms are preferably used. In the acrylic polymer, the content ratio of the constituent units of alkyl (meth)acrylate 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, per 100 parts by weight of the acrylic polymer.

[0077] The above acrylic polymer may, if necessary, contain constituent units derived from other monomers copolymerizable with the above alkyl (meth)acrylate, for purposes such as modifying cohesive strength, heat resistance, crosslinkability, and improving the dimensional stability of the adhesive layer. Examples of such monomers include the following monomers. Carboxylate-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: e.g., glycidyl (meth)acrylate, methylglycidyl (meth)acrylate, allyl glycidyl ether; Cyano group-containing monomers: e.g., acrylonitrile, methacrylonitrile; Keto group-containing monomers: for example, diacetone (meth)acrylamide, diacetone (meth)acrylate, vinyl methyl ketone, vinyl ethyl ketone, allyl acetate, vinyl acetate; 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; Monomers containing alkoxysilyl groups: 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 individually or in combination of two or more.

[0078] The weight-average molecular weight of the above acrylic polymer is preferably 600,000 to 1,600,000, and more preferably 800,000 to 1,500,000. Within this range, an adhesive layer can be formed that exhibits excellent heat resistance, excellent dimensional stability at high temperatures, and suppressed outgassing due to heating. The weight-average molecular weight can be measured by GPC (solvent: THF).

[0079] (Additives) The above-mentioned acrylic adhesive may contain any suitable additives as needed. Examples of such additives include crosslinking agents, crosslinking catalysts, tackifiers, plasticizers, pigments, dyes, fillers, antioxidants, conductive materials, antistatic agents, ultraviolet absorbers, light stabilizers, release modifiers, softeners, surfactants, flame retardants, antioxidants, and the like.

[0080] Examples of the above-mentioned crosslinking agents 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. Among these, epoxy-based crosslinking agents or isocyanate-based crosslinking agents are preferred.

[0081] Examples of the epoxy crosslinking agents mentioned above include N,N,N',N'-tetraglycidyl-m-xylenediline, diglycidylaniline, 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 "Epolite 1600"), neopentyl glycol diglycidyl ether (manufactured by Kyoeisha Chemical Co., Ltd., trade name "Epolite 1500NP"), ethylene glycol Recall diglycidyl ether (manufactured by Kyoeisha Chemical Co., Ltd., product name "Epolite 40E"), propylene glycol diglycidyl ether (manufactured by Kyoeisha Chemical Co., Ltd., product name "Epolite 70P"), polyethylene glycol diglycidyl ether (manufactured by Nippon Oil & Fats Co., Ltd., product name "Epiol E-400"), polypropylene glycol diglycidyl ether (manufactured by Nippon Oil & Fats Co., Ltd., product name "Epiol P-200"), sorbitol polyglycidyl ether (manufactured by Nagase ChemteX Corporation, product name "Denacol") Examples include 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 adipic acid ester, diglycidyl o-phthalate 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 adhesive strength, viscoelasticity of the adhesive layer, dimensional stability, and outgassing properties, and is typically 0.01 to 10 parts by weight, more preferably 0.03 to 7 parts by weight, per 100 parts by weight of the base polymer.

[0082] Specific examples of the above-mentioned isocyanate-based crosslinking agents 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; 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 derivative of hexamethylene diisocyanate (manufactured by Nippon Polyurethane Industry Co., Ltd., trade name "Coronate HX"); and the like. 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, more preferably 0.5 to 10 parts by weight, per 100 parts by weight of the base polymer.

[0083] 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, scorching (adhesive residue) to the light-transmitting support substrate when irradiated with laser light can be suppressed. 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 without leaving any adhesive residue in an environment of 260°C. Preferably, the heat-resistant adhesive contains an acrylic resin, a silicone resin, etc. as a base polymer.

[0084] The thickness of the adhesive layer is preferably 5 μm to 100 μm, and more preferably 10 μm to 50 μm.

[0085] The transmittance of the adhesive layer at a wavelength of 1032 nm is preferably 75% or more, more preferably 85% or more, and even more preferably 90% or more. The upper limit of the transmittance at a wavelength of 1032 nm is, for example, 97% (preferably 98%).

[0086] The transmittance of the adhesive layer described above to light at a wavelength of 600 nm is preferably 75% or more, more preferably 85% or more, and even more preferably 90% or more. The upper limit of the transmittance to light at a wavelength of 1032 nm is, for example, 97% (preferably 98%).

[0087] The transmittance of the adhesive layer described above at a wavelength of 355 nm is preferably 75% or more, more preferably 85% or more, and even more preferably 90% or more. The upper limit of the transmittance of light at a wavelength of 1032 nm is, for example, 97% (preferably 98%).

[0088] F. Use of adhesive sheets for temporary fixing of electronic components The adhesive sheet for temporarily fixing electronic components can be used as described in Section A with reference to Figures 2 and 3.

[0089] Examples of electronic components to be processed include semiconductor wafers, semiconductor packages, semiconductor chips, insulating materials for circuit boards, die attach films, semiconductor encapsulating resins, semiconductor protective films, resin compositions for forming semiconductor protective films, metal materials, ceramic materials, and the like. Multiple electronic components may be arranged, or only one may be arranged.

[0090] The electronic component can be attached to the adhesive sheet, for example, via another adhesive layer located on the opposite side of the first photothermal conversion layer from the second photothermal conversion layer.

[0091] As the above-mentioned support, a support made of any suitable material may be used. For example, supports made of glass such as borosilicate glass or quartz glass; sapphire; or acrylic resins such as PMMA (polymethyl methacrylate) or PC (polycarbonate) may be used. 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. In general, from the viewpoint of preventing residue, a smaller surface roughness of the support is preferable. Furthermore, it is preferable that the above-mentioned support is light-transmitting in the ultraviolet to infrared range. In particular, it is preferable that it is light-transmitting 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°. According to the present invention, even when using a support that conventionally makes it difficult to achieve good peeling (for example, one that generates residue or has poor pickability), desirable peeling can be achieved, which is advantageous in that it broadens the range of support selection.

[0092] After placing the electronic components on the adhesive sheet (i.e., the state shown in Figure 2(a)), the electronic components may be subjected to a predetermined process. Examples of such processes include grinding, dicing, die bonding, wire bonding, etching, chemical cleaning, vapor deposition, molding, redistribution layer formation, through-hole formation, or protection of the device surface.

[0093] As the laser light mentioned above, any appropriate wavelength of laser light can be used depending on the configuration of the adhesive sheet. The conditions for laser light irradiation can also be any appropriate conditions depending on the configuration of the 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 10600 nm, and even more preferably 900 nm to 1200 nm. The output power 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 power of the UV laser light is, for example, 0.1 W to 2.0 W. Furthermore, UV laser light can be selected if the first photothermal conversion layer can absorb the UV laser light. When UV laser light is irradiated, the heat generated in the first photothermal conversion layer causes thermal decomposition of the second photothermal conversion layer, resulting in peelability. [Examples]

[0094] The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. The evaluation methods in the examples are as follows. In the examples, unless otherwise specified, "parts" and "%" are based on weight.

[0095] [evaluation] (1) Tensile modulus of the first photothermal conversion layer (substrate) at 200°C The tensile modulus at 200°C was measured using a dynamic viscoelasticity analyzer (manufactured by TA Instrument, product name "RSA-3") under the following conditions. Measurement frequency: 1Hz Distortion: 0.05% Chuck spacing: 20mm Sample width: 10mm A heating rate of 5°C / min from 0°C to 250°C. (2) 5% weight loss temperature of the first photothermal conversion layer (substrate), the second photothermal conversion layer, and laminated structure A A differential thermal analyzer (TA Instruments, product name "Discovery TGA") was used to measure the temperature at which the weight of a given sample decreased by 5% compared to the dry weight of the sample before heating, under an N2 atmosphere and a flow rate of 25 ml / min. The dry weight of the sample refers to the weight after removing the water content from the sample. Specifically, approximately 0.01 g of the evaluation sample was placed in the analyzer described above. The temperature was raised from 20°C to 110°C at the aforementioned heating rate, and then cooled from 110°C to 20°C at a cooling rate of 10°C / min to remove the effect of the contained moisture and obtain the dry weight. The weight loss of the evaluation sample was measured again while raising the temperature from 20°C to 500°C at the aforementioned heating rate. From the obtained data, the temperature at which the weight loss was 5% was extracted. (3) Light transmittance of laminated structure A, adhesive sheet and adhesive layer The samples were placed in a spectrophotometer (product name "UV-VIS Ultraviolet-Visible Spectrophotometer SolidSpec3700," manufactured by Shimadzu Corporation), and the light transmittance in the wavelength range of 300 nm to 2500 nm was measured with the incident light perpendicular to each sample. The transmittance at wavelengths of 355 nm, 600 nm, and 1032 nm was extracted from the obtained transmission spectra. (4) Evaluation of laser debonding properties using IR laser The adhesive layer (thickness: 10 μm) on the first photothermal conversion layer (substrate) side of the adhesive sheet was attached with a hand roller to a thin glass (Matsunami Glass cover glass, rectangular No. 1, product name "C050701") measuring 50 mm wide, 70 mm long, and 0.12 mm thick, which mimicked a processed workpiece such as a semiconductor wafer. The adhesive sheet was then cut to the size of the thin glass. Subsequently, the adhesive layer (thickness: 30 μm, 1032 nm light transmittance: 93.91%) on the second photothermal conversion layer side was laminated with a hand roller to a support (a thick glass (Matsunami Glass large slide glass, standard large white-rimmed polished No. 2, product name "S9112") measuring 52 mm wide, 76 mm long, and 1.0 mm thick, which mimicked a light-transmitting support substrate). The laminate was then placed in an autoclave and degassed (40°C, 5 kgf, 10 minutes) to remove trapped air bubbles and prepare a laminate sample. The fabricated laminated samples were irradiated with laser light from the support side, and laser debonding properties were evaluated. Specifically, a laser with a wavelength of 1032 nm and a beam diameter of approximately 200 μmφ was used, and pulse scanning was performed at an output of 8.4 W and a frequency of 25 kHz, with intervals of approximately 60 μm in both the vertical and horizontal directions. After irradiating the laminated samples with laser light, the debonding properties were evaluated according to the following criteria. The evaluation of laser debonding properties was as follows: In the debonding process of thin and thick glass, a level where debonding could be easily performed by lifting one point on the outer edge of the laminated sample with a cutter blade was considered passable (○), a level where debonding could only be performed after lifting the entire outer edge with a cutter blade was considered △, and a level where debonding could not be performed even when the cutter blade was inserted into the outer edge, or where the thin glass (workpiece) broke was considered failing (×). (5) Evaluation of laser debonding properties using UV laser A laminated sample was obtained in the same manner as in evaluation (4) above. The fabricated laminated samples were irradiated with laser light from the support side, and laser debonding properties were evaluated. Specifically, the settings were: wavelength 355 nm, beam width approximately 10 μm, beam length approximately 1.5 mm, and energy density 0.5 J / cm². 2Using a line laser, a pulse scan was performed at a power output of 0.75W and a frequency of 10kHz, such that the spacing between the center lines was approximately 10μm in the width direction and overlapped by approximately 0.2mm or more in the length direction. (6) Resistance to chemicals 0.1 mL of N-methyl-2-pyrrolidone (manufactured by Kishida Chemical Co., Ltd.) was dropped onto the second photothermal conversion layer, and then left at 25°C for 15 minutes. After wiping off the N-methyl-2-pyrrolidone (manufactured by Kishida Chemical Co., Ltd.), the chemical resistance was evaluated based on whether or not the second photothermal conversion layer peeled off. In the table, no peeling was indicated as pass (○), and peeling was indicated as fail (×). (7) Visibility The visibility through the adhesive sheet was evaluated. Specifically, visibility was assessed by whether or not the chip could be seen through the adhesive sheet under fluorescent lighting. If it was visible, it was marked as a pass (○), and if it was not visible, it was marked as a fail (×).

[0096] [Manufacturing Example 1] Composition A for forming the second photothermal conversion layer Composition A for forming a photothermal conversion layer was prepared by mixing 50 parts by weight of an acrylic polymer with a weight-average molecular weight (Mw) of approximately 22,000, obtained by copolymerizing methyl methacrylate and acryloyl-modified glycerin methacrylate in a 50:50 (mol ratio), 50 parts by weight of a pentaerythritol-based polyfunctional acrylate, methyl isobutyl ketone, 0.5 parts by weight of a photopolymerization initiator (BASF, trade name "Omnirad127D"), 15 parts by weight of a near-infrared absorber (cesium oxide tungsten dispersion, trade name "YMF-02A", Sumitomo Metal Mining Co., Ltd.), and ethyl acetate.

[0097] [Manufacturing Example 2] Composition B for forming the second photothermal conversion layer A second photothermal conversion layer forming composition B was prepared in the same manner as in Production Example 1, except that the amount of infrared absorbent (cesium tungsten oxide dispersion, trade name "YMF-02A", manufactured by Sumitomo Metal Mining Co., Ltd.) was set to 7.5 parts by weight.

[0098] [Manufacturing Example 3] Composition C for forming the second photothermal conversion layer A second photothermal conversion layer forming composition C was prepared in the same manner as in Production Example 1, except that the amount of infrared absorbent (cesium tungsten oxide dispersion, trade name "YMF-02A", manufactured by Sumitomo Metal Mining Co., Ltd.) was set to 23 parts by weight.

[0099] [Manufacturing Example 4] Composition D for forming the second photothermal conversion layer Composition D for forming a photothermal conversion layer was prepared by mixing 50 parts by weight of an acrylic polymer with a weight-average molecular weight (Mw) of approximately 22,000 obtained by copolymerizing methyl methacrylate and acryloyl-modified glycerin methacrylate in a 50:50 (mol ratio); 50 parts by weight of a pentaerythritol-based polyfunctional acrylate; methyl isobutyl ketone; 10 parts by weight of an acrylic polymer with a weight-average molecular weight (Mw) of approximately 29,000 obtained by copolymerizing methyl methacrylate and acryloyl-modified glycerin methacrylate in a 71:29 (mol ratio); butyl acetate; 0.5 parts by weight of a photopolymerization initiator (BASF, trade name "Omnirad127D"); 15 parts by weight of a near-infrared absorber (cesium oxide tungsten dispersion, trade name "YMF-02A", Sumitomo Metal Mining Co., Ltd.); and ethyl acetate.

[0100] [Manufacturing Example 5] Composition E for forming the second photothermal conversion layer 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 with a weight-average molecular weight (Mw) of approximately 29,000, obtained by copolymerizing methyl methacrylate and acryloyl-modified glycerin methacrylate in a 71:29 (mol ratio)" was set to 40 parts by weight.

[0101] [Manufacturing Example 6] Composition F for forming the second photothermal conversion layer Composition F for forming a photothermal conversion layer was prepared by mixing 100 parts by weight of an acrylic polymer with a weight-average molecular weight (Mw) of approximately 29,000, obtained by copolymerizing methyl methacrylate and acryloyl-modified glycerin methacrylate in a 71:29 (mol ratio); butyl acetate; 0.5 parts by weight of a photopolymerization initiator (BASF, trade name "Omnirad127D"); 15 parts by weight of a near-infrared absorber (cesium tungsten oxide dispersion, trade name "YMF-02A", Sumitomo Metal Mining Co., Ltd.); and ethyl acetate.

[0102] [Manufacturing Example 7] Composition G for forming the second photothermal conversion layer A second photothermal conversion layer forming composition G was prepared in the same manner as in Production Example 1, except that the amount of infrared absorbent (cesium tungsten oxide dispersion, trade name "YMF-02A", manufactured by Sumitomo Metal Mining Co., Ltd.) was set to 4 parts by weight.

[0103] [Example 1] Composition A for forming the second photothermal conversion layer, obtained in Production Example 1, was applied to one side of a polyimide film (Toray DuPont, product name "Kapton 100H", thickness: 25 μm) so that the thickness after solvent evaporation (drying) was 2 μm. After drying, the second photothermal conversion layer was formed on the polyimide film. A polyethylene terephthalate film with a silicone release agent treated surface (Toray, product name "Therapiel", thickness: 38 μm) was laminated between rolls, and an integrated light intensity of 1380 mJ / cm² was applied from the side of the polyethylene terephthalate film with the silicone release agent treated surface. 2 UV irradiation was performed under the specified conditions. Subsequently, the polyethylene terephthalate film with the silicone release agent treated surface was peeled off to obtain a laminate (second photothermal conversion layer / first photothermal conversion layer (substrate: polyimide film)). An adhesive layer with a thickness of 10 μm was formed by coating the first photothermal conversion layer (substrate) side of the laminate. An adhesive layer with a thickness of 30 μm was also formed by coating the second photothermal conversion layer side of the laminate. The adhesive sheets obtained in this manner were subjected to the above evaluation. The results are shown in Table 1. The adhesives forming the first photothermal conversion layer (substrate) side adhesive layer and the second photothermal conversion 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 then 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 crosslinking agent (manufactured by Mitsubishi Gas Chemical Co., Ltd., trade name "Tetrad C") was added to the ethyl acetate solution to obtain an adhesive for the second photothermal conversion layer side adhesive layer. In addition, 2 parts by weight of an epoxy crosslinking agent (manufactured by Mitsubishi Gas Chemical Co., Ltd., trade name "Tetrad C") was added to the above ethyl acetate solution to obtain an adhesive for the first photothermal conversion layer (substrate) side adhesive layer. The light transmittance of the adhesive layer on the second photothermal conversion layer side was 91.1% at a wavelength of 355 nm, 92.8% at a wavelength of 600 nm, and 93.91% at a wavelength of 1032 nm.

[0104] [Examples 2-4] An adhesive sheet was manufactured in the same manner as in Example 1, except that the thickness of the second photothermal conversion layer was as shown in Table 1. The obtained adhesive sheet was subjected to the above evaluation. The results are shown in Table 1.

[0105] [Example 5] An adhesive sheet was manufactured in the same manner as in Example 1, except that composition B for forming the second photothermal conversion layer was used instead of composition A for forming the second photothermal conversion layer, and the thickness of the second photothermal conversion layer was set to 5 μm. The obtained adhesive sheet was subjected to the above evaluation. The results are shown in Table 1.

[0106] [Example 6] An adhesive sheet was manufactured in the same manner as in Example 1, except that composition C for forming the second photothermal conversion layer was used instead of composition A for forming the second photothermal conversion layer, and the thickness of the second photothermal conversion layer was set to 20 μm. The obtained adhesive sheet was subjected to the above evaluation. The results are shown in Table 1.

[0107] [Example 7] An adhesive sheet was manufactured in the same manner as in Example 1, except that a polyethylene terephthalate film (Toray Industries, Ltd., product name "Lumirror S27", thickness: 38 μm) was used instead of a polyimide film (Toray DuPont, product name "Kapton 100H", thickness: 25 μm), and the thickness of the second photothermal conversion layer was set to 5 μm. The obtained adhesive sheet was subjected to the above evaluation. The results are shown in Table 2.

[0108] [Example 8] An adhesive sheet was manufactured in the same manner as in Example 7, except that the second photothermal conversion layer forming composition F was used instead of the second photothermal conversion layer forming composition A. The obtained adhesive sheet was subjected to the above evaluation. The results are shown in Table 2.

[0109] [Example 9] An adhesive sheet was manufactured in the same manner as in Example 1, except that a polyethylene naphthalate film (manufactured by Teijin Film Solutions, product name "Teonex® Film Q51C-50", thickness: 50 μm) was used instead of a polyimide film (manufactured by Toray DuPont, product name "Kapton 100H", thickness: 25 μm), and the thickness of the second photothermal conversion layer was set to 5 μm. The obtained adhesive sheet was subjected to the above evaluation. The results are shown in Table 2.

[0110] [Example 10] An adhesive sheet was manufactured in the same manner as in Example 1, except that a polyether ether ketone film (manufactured by Kurabo Industries Ltd., product name "EXPEEK", thickness: 12 μm) was used instead of a polyimide film (manufactured by Toray DuPont, product name "Kapton 100H", thickness: 25 μm), and the thickness of the second photothermal conversion layer was set to 5 μm. The obtained adhesive sheet was subjected to the above evaluation. The results are shown in Table 2.

[0111] [Comparative Example 1] Adhesive sheets were obtained by forming adhesive layers (10 μm and 30 μm thick) on both sides of a polyimide film (manufactured by Toray DuPont, product name "Kapton 100H", thickness: 25 μm). The obtained adhesive sheets were subjected to the above evaluation. The results are shown in Table 3.

[0112] [Comparative Example 2] Adhesive sheets were obtained by forming adhesive layers (thickness 10 μm and 30 μm) on both sides of a polyethylene terephthalate film (manufactured by Toray Industries, Inc., product name "Lumirror S27", thickness: 38 μm). The obtained adhesive sheets were subjected to the above evaluation. The results are shown in Table 3.

[0113] [Comparative Example 3] The resin composition was prepared in the same manner as in Production Example 1, except that a near-infrared absorber (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 this resin composition was used instead of the second photothermal conversion layer forming composition A, and a resin layer with a thickness of 5 μm was formed. An adhesive sheet was then obtained. The obtained adhesive sheet was subjected to the above evaluation. The results are shown in Table 3.

[0114] [Comparative Example 4] Composition I for forming the second photothermal conversion layer was prepared by mixing 100 parts by weight of carbon black printing ink NB300 (manufactured by Dainichi Seika Co., Ltd.) and 5 parts by weight of an isocyanate-based curing agent (manufactured by Dainichi Seika Co., Ltd., product name "Lamic B Birdner"). NB300 contains a polyurethane vinyl acetate-vinyl chloride copolymer as a binder resin, and an intensity peak, likely representing urethane, was confirmed by infrared (IR) testing. Composition I for forming the second photothermal conversion layer was applied to one side of a polyethylene terephthalate film (manufactured by Toray Industries, Ltd., product name "Lumirror S105", thickness: 25 μm) using a gravure coater so that the thickness after solvent evaporation (drying) was 0.2 μm. After drying, a laminate (second photothermal conversion layer / first photothermal conversion layer (substrate: polyethylene terephthalate film)) was obtained. An adhesive layer with a thickness of 10 μm was formed on the first photothermal conversion layer (substrate) side of the laminate. An adhesive layer with a thickness of 30 μm was also formed on the second photothermal conversion layer side of the laminate. The resulting adhesive sheets were subjected to the above evaluation. 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 the second photothermal conversion layer was prepared by mixing 100 parts by weight of carbon black printing ink CVL-PR (manufactured by DIC Corporation) and 4 parts by weight of an isocyanate-based curing agent (manufactured by DIC Corporation, product name "CVL Hardener No. 10"). CVL-PR contains a polyurethane vinyl acetate-vinyl chloride copolymer as a binder resin, and an intensity peak, likely urethane, was confirmed by IR testing. Composition II for forming the second photothermal conversion layer was applied to one side of a polyethylene terephthalate film (manufactured by Toray Industries, Ltd., product name "Lumirror S105", thickness: 25 μm) using a gravure coater so that the thickness after solvent evaporation (drying) was 3 μm. After drying, a laminate (second photothermal conversion layer / first photothermal conversion layer (substrate: polyethylene terephthalate film)) was obtained. An adhesive layer with a thickness of 10 μm was formed on the first photothermal conversion layer (substrate) side of the laminate. An adhesive layer with a thickness of 30 μm was also formed on the second photothermal conversion layer side of the laminate. The resulting adhesive sheets were subjected to the above evaluation. 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 adhesive sheet of the present invention has excellent visible light transmittance and exhibits debonding properties to both IR laser light and UV laser light. [Explanation of Symbols]

[0120] 10 First photothermal conversion layer 20 Second photothermal conversion layer 30 Adhesive layer 40 Another adhesive layer 110 Adhesive sheet for temporary fixing of electronic components

Claims

1. A laminated structure A comprises a first photothermal conversion layer and a second photothermal conversion layer disposed on at least one side of the first photothermal conversion layer. An adhesive sheet for temporarily fixing electronic components, comprising an adhesive layer disposed on at least one side of the laminated structure A, The adhesive sheet for temporarily fixing the electronic component has a transmittance of 75% or less of light at a wavelength of 1032 nm, and The adhesive sheet for temporarily fixing the electronic component has a transmittance of 50% or less of light at a wavelength of 355 nm. The temperature at which the first photothermal conversion layer loses 5% of its weight is 300°C or higher. Adhesive sheet for temporarily fixing electronic components.

2. The adhesive sheet for temporarily fixing electronic components according to claim 1, wherein the first photothermal conversion layer is a layer capable of absorbing ultraviolet light.

3. The adhesive sheet for temporarily fixing electronic components according to claim 1, wherein the first photothermal conversion layer is made of a polyimide resin, a polyester resin, or a polyetheretherketone resin.

4. The adhesive sheet for temporarily fixing electronic components according to claim 1, wherein the second photothermal conversion layer is a layer capable of absorbing near-infrared rays.

5. The adhesive sheet for temporarily fixing electronic components according to claim 1, wherein the second photothermal conversion layer contains a near-infrared absorbent.

6. The adhesive sheet for temporarily fixing electronic components according to claim 5, wherein the near-infrared absorbing agent is a substance containing the element tungsten.

7. The adhesive sheet for temporarily fixing electronic components according to claim 5, wherein the near-infrared absorbent is a substance containing cesium.

8. The adhesive sheet for temporarily fixing electronic components according to claim 1, wherein the 5% weight loss temperature of the second photothermal conversion layer is 300°C or higher.

9. A method for processing electronic components, comprising placing the electronic components on an adhesive sheet according to any one of claims 1 to 8, and then performing a predetermined process on the electronic components.

10. The method for processing an electronic component according to claim 9, wherein the processing is grinding, dicing, die bonding, wire bonding, etching, vapor deposition, chemical cleaning, molding, redistribution layer formation, through-hole formation, or protection of the device surface.

11. An adhesive sheet for temporarily fixing electronic components according to any one of claims 1 to 8 is placed on a support, The electronic component is placed on the adhesive sheet for temporary fixing of the electronic component, and then, This includes irradiating the adhesive sheet with light to separate the first photothermal conversion layer and the second photothermal conversion layer. A method for separating temporarily fixed electronic components from their support.

12. The method for separating a temporarily fixed electronic component from a support according to claim 11, wherein the light is laser light.

13. The method for separating a temporarily fixed electronic component from a support according to claim 12, wherein the wavelength of the laser light is 800 nm or more.

14. The method for separating a temporarily fixed electronic component from a support according to claim 12, wherein the wavelength of the laser light is 380 nm or less.

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