CN118043417A

CN118043417A - Adhesive sheet for temporarily fixing electronic component and method for treating electronic component

Info

Publication number: CN118043417A
Application number: CN202280066165.1A
Authority: CN
Inventors: 上野周作; 加藤和通; 平山高正
Original assignee: Nitto Denko Corp
Current assignee: Nitto Denko Corp
Priority date: 2021-09-29
Filing date: 2022-03-30
Publication date: 2024-05-14
Also published as: WO2023053538A1; JP2023049530A; TW202313336A

Abstract

The invention provides an adhesive sheet which is used for temporarily fixing an electronic component to a support, shows peelability from the support by irradiation of laser, and can reduce residues on the support after peeling. The adhesive sheet for temporarily fixing electronic components comprises a photothermal conversion layer and a thermal decomposition layer directly arranged on the photothermal conversion layer, wherein the 5% weight loss temperature of the thermal decomposition layer is lower than the 5% weight loss temperature of the photothermal conversion layer. In one embodiment, the light-to-heat conversion layer has a 5% weight loss temperature of 300 to 600 ℃.

Description

Adhesive sheet for temporarily fixing electronic component and method for treating electronic component

Technical Field

The present invention relates to an adhesive sheet for temporarily fixing electronic components and a method for treating electronic components.

Background

The demand for miniaturization and thinning of electronic components has increased year by year, and for example, in order to improve the characteristics of semiconductor devices, the trend of thinning semiconductor wafers is being accelerated centering on the fields of power devices and the like. In applications for processing/treating a thin and fragile semiconductor substrate (for example, a silicon wafer), a method of temporarily fixing a thin and fragile semiconductor substrate to a translucent hard substrate (support) such as glass with a liquid adhesive to reduce the risk of breakage during processing/treatment is widely used (for example, patent document 1). In such a temporary fixing method, a light-to-heat conversion layer and a bonding layer are formed on a light-transmitting substrate through a plurality of film forming steps, and the following laser light release properties are required: the object to be processed is firmly fixed during processing, and laser light with a prescribed wavelength is irradiated during peeling, and the light-heat conversion layer absorbs the light and converts the light into heat for thermal decomposition, thereby enabling easy separation of the object to be processed and the light-transmitting substrate. However, since the decomposition product is sintered when the photothermal conversion layer is thermally decomposed, there is a problem that residues which are difficult to clean are generated on the hard substrate (support) which is in contact. Therefore, the use of a rigid substrate (support) for one-time use or recycling entails a great cleaning load, and is one of the factors that increase the manufacturing cost of semiconductor devices.

Prior art literature

Patent literature

Patent document 1: japanese patent No. 4565804

Disclosure of Invention

Problems to be solved by the invention

The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an adhesive sheet which is provided for temporary fixation of an electronic component to a support, exhibits peelability from the support by irradiation of laser light, and can reduce residues on the support after peeling.

Solution for solving the problem

The adhesive sheet for temporarily fixing electronic components comprises a photothermal conversion layer and a thermal decomposition layer directly arranged on the photothermal conversion layer, wherein the 5% weight loss temperature of the thermal decomposition layer is lower than the 5% weight loss temperature of the photothermal conversion layer.

In one embodiment, the light-to-heat conversion layer has a 5% weight loss temperature of 300 to 600 ℃.

In one embodiment, the 5% weight loss temperature of the thermal decomposition layer is 250 to 400 ℃.

In one embodiment, the light transmittance of the photothermal conversion layer at 355nm is 50% or less.

In one embodiment, the light-heat conversion layer is a resin film made of polyimide-based resin.

In one embodiment, the transmittance of light having a wavelength of 355nm of the thermal decomposition layer is 80% or more.

In one embodiment, the light transmittance of the photothermal conversion layer at a wavelength of 1032nm is 50% or less.

In one embodiment, the light-to-heat conversion layer is a colored film.

In one embodiment, the transmittance of the thermally decomposed layer for light having a wavelength of 1032nm is 80% or more.

In one embodiment, the thermal decomposition layer has a gel fraction of 70% or more.

In one embodiment, the tensile elastic modulus of the photothermal conversion layer at 200 ℃ is 5MPa to 2GPa.

In one embodiment, the adhesive sheet for temporarily fixing an electronic component further includes an adhesive layer, and the adhesive layer, the photothermal conversion layer, and the thermal decomposition layer are laminated in this order.

According to another aspect of the present invention, there is provided a method of processing an electronic component. In this processing method, after an electronic component is disposed on the adhesive sheet, a predetermined process is performed on the electronic component.

In one embodiment, the process is a grinding process, a dicing process, a die bonding, a wire bonding, an etching, an evaporation, a molding, a re-wiring formation, a through hole formation, or a protection of the device surface.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, it is possible to provide an adhesive sheet for temporarily fixing an electronic component to a support, which exhibits peelability from the support by irradiation of laser light and can reduce residues on the support after peeling.

Drawings

Fig. 1 is a schematic cross-sectional view of an adhesive sheet according to an embodiment of the present invention.

Fig. 2 is a view illustrating a method of using the adhesive sheet according to an embodiment of the present invention.

Detailed Description

A. summary of adhesive sheet for temporarily fixing electronic component

Fig. 1 is a schematic cross-sectional view of an adhesive sheet for temporary fixation of electronic components according to an embodiment of the present invention. The adhesive sheet 100 for temporarily fixing electronic components includes a photothermal conversion layer 10 and a thermal decomposition layer 20 directly disposed on the photothermal conversion layer. The photothermal conversion layer absorbs light of a predetermined wavelength and converts the light into heat. The thermal decomposition layer is heated by the heat generation of the light-heat conversion layer, and as a result, the thermal decomposition layer is decomposed. As a result, the adhesive sheet for temporarily fixing electronic components (hereinafter also simply referred to as an adhesive sheet) exhibits peelability. In one embodiment, the light-heat conversion layer generates heat by irradiation with laser light. In the present specification, "thermal decomposition" means that a weight loss of 5% or more can be generated by heating at 250 ℃ or more. The term "direct placement" refers to a state in which no other layer is placed between the light-heat conversion layer and the thermal decomposition layer, but the two layers are in contact with each other. On the other hand, the pressure-sensitive adhesive sheet may further include other layers as long as the effects of the present invention can be obtained. For example, as shown in fig. 1, any suitable adhesive layer 30 may be disposed on the opposite side of the thermal decomposition layer 20 of the light-to-heat conversion layer 10. That is, in one embodiment, the adhesive sheet 100 in which the adhesive layer 30, the photothermal conversion layer 10, and the thermal decomposition layer 20 are sequentially laminated may be provided.

In the above-mentioned adhesive sheet, the 5% weight loss temperature of the thermal decomposition layer is lower than the 5% weight loss temperature of the photothermal conversion layer. The 5% weight loss temperature is a temperature at which the weight of a sample to be evaluated is reduced by 5% by weight relative to the weight before the temperature rise when the temperature of the sample is raised. The weight loss temperature of 5% was measured using a differential thermal analyzer under conditions of a temperature rise of 10℃per minute and a flow rate of 25 ml/min under an air atmosphere.

In one embodiment, the adhesive sheet is used by adhering a thermal decomposition layer as an adhesive layer to a support and disposing an electronic component (for example, a semiconductor component such as a semiconductor wafer) on the side of the photothermal conversion layer. In the present invention, the layer that absorbs laser light and generates heat (photothermal conversion layer) and the layer that is more easily thermally decomposed than the photothermal conversion layer and contributes to separation (pyrolytic layer) are provided as different layers, whereby separation of the electronic component from the support can be easily performed and generation of residue on the support can be prevented. More specifically, the pressure-sensitive adhesive sheet of the present invention can be handled as shown in fig. 2 and described below, and the above-described effects can be obtained.

(1) The adhesive sheet 100 is disposed on the support 200 so that the thermally decomposed layer side becomes the support 200 side, and the electronic component 300 as the object to be processed is disposed on the side of the adhesive sheet 100 opposite to the support 200 (fig. 2 (a)).

(2) When the adhesive sheet 100 disposed on the support 200 is irradiated with laser light, the light-to-heat conversion layer 10 generates heat, and the generated heat propagates to the adjacent thermal decomposition layer 20, whereby the thermal decomposition layer 20 is decomposed at the interface with the light-to-heat conversion layer 10 (fig. 2 (b)). In one embodiment, the decomposition of the thermally decomposed layer occurs locally.

(3) As a result, the thermal decomposition layer 20 changes shape at the interface with the photothermal conversion layer 10, and loses adhesiveness, and the photothermal conversion layer 10 can be peeled off from the support 200 (fig. 2 (c)). As a result, the electronic component can be separated from the support.

(4) Next, the thermally decomposed layer 20 on the support 200 is removed, whereby the clean support 200 with the residue suppressed can be recovered (fig. 2 (d)).

In the present invention, by providing the photothermal conversion layer and the thermal decomposition layer, the pressure-sensitive adhesive sheet can be peeled off by the above operation, and the electronic component can be separated from the support with reduced damage to the electronic component. In addition, by setting the 5% weight loss temperature of the thermal decomposition layer to be lower than the 5% weight loss temperature of the photothermal conversion layer, peeling of the thermal decomposition layer/photothermal conversion layer interface is promoted, and the above effect becomes remarkable.

In addition, conventionally, when the thermally decomposed layer is also unnecessarily heated by laser irradiation for heating the photothermal conversion layer, the thermally decomposed product of the thermally decomposed layer may be sintered on the support, and the clean support may be recovered. In the present invention, in the step (4), the thermal decomposition layer is removed by immersing in an organic solvent (e.g., toluene), so that most of the thermal decomposition layer on the support can be removed at the same time, and the support can be easily recovered. Such an effect is more remarkable by optimizing the gel fraction of the thermally decomposed layer (details will be described later).

As the support, a support made of any appropriate material may be used. For example, glass such as borosilicate glass and quartz glass; sapphire; and a support made of an acrylic resin such as PMMA (polymethyl methacrylate) or PC (polycarbonate). In one embodiment, a support having no organic layer on the surface is used. The arithmetic surface roughness Ra of the support is, for example, 0.3nm to 100nm, more preferably 0.4nm to 50nm. The arithmetic surface roughness Ra can be measured in accordance with JIS B0601. In general, from the viewpoint of preventing residues, the surface roughness of the support is preferably small. The support is preferably transparent in the ultraviolet to infrared range. It is particularly preferable that the light-transmitting member transmits laser light of any wavelength selected. The transmittance of the support at the wavelength of the 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 °, more preferably 3 ° to 120 °. The support preferably has solvent resistance. According to the present invention, it is advantageous in that even when a support that has been difficult to achieve good separation (for example, generation of residue or the like) is used, a preferred separation can be achieved, that is, in that the support selection range is widened.

The initial adhesion at 23℃of the thermal decomposition layer to the glass plate is preferably 0.3N/20mm to 20N/20mm, more preferably 0.5N/20mm to 15N/20mm. In such a range, an adhesive sheet suitable for temporary fixation can be obtained without positional displacement or the like on the support. Adhesion according to JIS Z0237: 2000. Specifically, the measurement was performed by bonding the thermally decomposed layer to a glass plate (arithmetic average surface roughness Ra: 10.+ -. 8 nm) by reciprocating a 2kg roller 1 time and then peeling the adhesive sheet under conditions of a peeling angle of 180 degrees and a peeling speed (stretching speed) of 300 mm/min. The adhesive force of the thermally decomposed layer may be changed by laser irradiation, and in this specification, "initial adhesive force" means adhesive force before irradiation with laser.

The thickness of the pressure-sensitive adhesive sheet is preferably 10 μm to 500. Mu.m, more preferably 20 μm to 400. Mu.m.

In one embodiment, the pressure-sensitive adhesive sheet has a transmittance of light having a wavelength of 355nm of 0% to 50%, more preferably 0% to 40%, and still more preferably 0% to 35%. In another embodiment, the transmittance of light having a wavelength of 1032nm is 0% to 50%, more preferably 0% to 40%, and still more preferably 0% to 35%.

B. Photo-thermal conversion layer

The weight loss temperature of the light-to-heat conversion layer at 5% is preferably 300 to 600 ℃, more preferably 315 to 590 ℃. When the content is within such a range, the above-mentioned effects of the present application become remarkable.

As described above, the 5% weight loss temperature of the thermal decomposition layer is lower than the 5% weight loss temperature of the light-to-heat conversion layer. The difference between the 5% weight loss temperature of the thermal decomposition layer and the 5% weight loss temperature of the photothermal conversion layer is preferably 5 to 300 ℃, more preferably 8 to 280 ℃. When the content is within such a range, the above-mentioned effects of the present application become remarkable.

The thickness of the photothermal conversion layer is preferably 5 μm to 200 μm, more preferably 10 μm to 150 μm.

In one embodiment, the transmittance of the light having a wavelength of 355nm of the photothermal conversion layer is 50%, more preferably 40% or less, still more preferably 35% or less, and most preferably 0%. If the amount is within this range, a photothermal conversion layer which absorbs UV laser light and easily generates heat can be formed.

In one embodiment, the light transmittance of the photothermal conversion layer at a wavelength of 1032nm is 50% or less, more preferably 40% or less, still more preferably 35% or less, and most preferably 0%. If the amount is within this range, a light-heat conversion layer that absorbs IR laser light and easily generates heat can be formed.

The tensile elastic modulus of the photothermal conversion layer at 200℃is preferably 5MPa to 2GPa, more preferably 10MPa to 1.8GPa. In this case, the decomposition gas generated in the thermal decomposition layer can be prevented from moving to the side opposite to the thermal decomposition layer, and the decomposition gas can be caused to stay in the vicinity of the interface between the thermal decomposition layer and the light-to-heat conversion layer, so that the separability of the electronic component from the support can be improved. For example, in the case where the pressure-sensitive adhesive layer is disposed on the side of the photothermal conversion layer opposite to the thermal decomposition layer, the decomposition gas can be prevented from flowing into the interface between the pressure-sensitive adhesive layer and the electronic component, and the electronic component can be separated from the support in a state where the electronic component is protected by the photothermal conversion layer. The tensile elastic modulus can be measured using a dynamic viscoelasticity measuring device. Specific measurement methods are described later. Even when the light-heat conversion layer is a multilayer, the tensile elastic modulus is measured by integrating the light-heat conversion layer. In one embodiment, the tensile elastic modulus of the photothermal conversion layer at 200 ℃ is 1GPa or more, more preferably 1.4GPa or more. If the ratio is within this range, the photothermal conversion layer can function as a base material. As the light-heat conversion layer having such characteristics, a resin film described later can be used, and a resin film made of a polyimide-based resin can be preferably used.

B-1 photo-thermal conversion layer capable of absorbing UV light

In one embodiment, a light-to-heat conversion layer capable of absorbing UV light (hereinafter, also referred to as a UV-absorbing light-to-heat conversion layer) is formed. For the adhesive sheet provided with the UV-absorbing photothermal conversion layer, a peeling operation may be performed using a UV laser. The transmittance of light having a wavelength of 355nm of the UV-absorbing photothermal conversion layer is 50%, more preferably 40% or less, still more preferably 35% or less, and most preferably 0%. In one embodiment, the transmittance of the photothermal conversion layer can be calculated by the equation (total light-absorptance).

In one embodiment, the UV-absorbing light-heat conversion layer is a resin film. The resin film may be made of any suitable resin as long as it can absorb UV light. Examples of the resin constituting the resin film include polyimide-based resins, polyether-ether-ketone-based resins, polyethylene naphthalate-based resins, acrylic-based resins, and epoxy-based resins. Among them, polyimide-based resins are preferable.

As the resin film, a colored film colored so as to absorb predetermined UV light can be used. The colored film may be a film having a colored print layer, or may be a resin film containing a pigment and/or a dye. The printing layer may be formed by gravure printing, screen printing, or the like. The thickness of the print layer is, for example, preferably more than 0 μm and 15 μm or less, more preferably 0.3 μm to 10 μm, still more preferably 0.5 μm to 8 μm. Further, it is more preferably 0.6 μm to 5. Mu.m, particularly preferably 0.8 μm to 3. Mu.m. Further, as the UV-absorbing light-heat conversion layer, a colored metal thin film may be used.

In another embodiment, the UV-absorbing light-to-heat conversion layer may be a resin layer formed by applying a composition for forming a light-to-heat conversion layer. The resin layer contains, for example, an ultraviolet absorber. The resin layer may be an adhesive layer including an adhesive. Examples of the adhesive include a pressure-sensitive adhesive and an active energy ray-curable adhesive.

(Ultraviolet absorber)

As the ultraviolet absorber, any suitable ultraviolet absorber may be used as long as it is a compound that absorbs ultraviolet light (for example, has a wavelength of 355 nm). Examples of the ultraviolet absorber include benzotriazole-based ultraviolet absorbers, benzophenone-based ultraviolet absorbers, triazine-based ultraviolet absorbers, salicylate-based ultraviolet absorbers, and cyanoacrylate-based ultraviolet absorbers. Among them, a triazine-based ultraviolet absorber or a benzotriazole-based ultraviolet absorber is preferable, and a triazine-based ultraviolet absorber is particularly preferable.

Examples of the hydroxyphenyl triazine ultraviolet light absorber include a reaction product of 2- (4, 6-bis (2, 4-dimethylphenyl) -1,3, 5-triazin-2-yl) -5-hydroxyphenyl with [ (C10-C16 (mainly C12-C13) alkoxy) methyl ] oxirane (trade name "TINUVIN 400", manufactured by Pasteur company), a reaction product of 2- [4, 6-bis (2, 4-dimethylphenyl) -1,3, 5-triazin-2-yl ] -5- [3- (dodecyloxy) -2-hydroxypropoxy ] phenol, a reaction product of 2- (2, 4-dihydroxyphenyl) -4, 6-bis- (2, 4-dimethylphenyl) -1,3, 5-triazine with (2-ethylhexyl) -glycidic acid ester (trade name "TINUVIN 405", manufactured by Pasteur company), a reaction product of 2, 4-bis (2-hydroxy-4-butoxyphenyl) -6- (2, 4-dibutoxyphenyl) -1,3, 5-triazine (trade name "TINUF 460"), and a reaction product of 2- (2, 4-dimethylphenyl) -1,3, 5-triazine with (2-ethylhexyl) -glycidic acid ester (trade name "TINUVIN 405", manufactured by Pasteur company), a reaction product of 2, 4-bis (2-hydroxy-4-butoxyphenyl) -6- (2, 4-dibutoxyphenyl) -1,3, 5-triazine (trade name "TINUF) -7-base (trade name" BASF-7-3, 7-hydroxy-3-2-hydroxy-methyl-2-hydroxy-phenyl-2-hydroxy-carbonyl-amine 2- (4, 6-diphenyl-1, 3, 5-triazin-2-yl) -5- [2- (2-ethylhexanoyloxy) ethoxy ] -phenol (trade name "ADK STAB LA-46", manufactured by ADEKA Co., ltd.), 2- (2-hydroxy-4- [ 1-octyloxycarbonylethoxy ] phenyl) -4, 6-bis (4-phenylphenyl) -1,3, 5-triazine (trade name "TINUVIN 479", manufactured by BASF), trade name "TINUVIN 477" manufactured by BASF, and the like.

As benzotriazole-based ultraviolet absorbers (benzotriazole-based compounds), for example, a mixture of 2- (2-hydroxy-5-tert-butylphenyl) -2H-benzotriazole (trade name "TINUVIN PS", manufactured by Basf Co.), phenylpropionic acid and 2-ethylhexyl 3- (2H-benzotriazol-2-yl) -5- (1, 1-dimethylethyl) -4-hydroxy (C7-9 side chain and linear alkyl group) (trade name "TINUVIN 384-2", manufactured by Basf Co.), octyl 3- [ 3-tert-butyl-4-hydroxy-5- (5-chloro-2H-benzotriazol-2-yl) phenyl ] propionate and 2-ethylhexyl 3- [ 3-tert-butyl-4-hydroxy-5- (5-chloro-2H-benzotriazol-2-yl) phenyl ] propionate (trade name "TINUVIN 109", manufactured by Basf Co.), 2- (2H-benzotriazol-2-yl) -4, 6-bis (1-methyl-1-phenylethyl) phenol (trade name "TINUVIN 384-2", manufactured by Basf Co., ltd.), 2- (2H-benzotriazol-2-yl) -4, 6-bis (1-methyl-phenylethyl) phenol (trade name "1, 3-tert-butyl-4-hydroxy-5- (5-chloro-2H-benzotriazol-2-yl) phenyl ] propionate (trade name" TINUVIN 109", manufactured by Basf-H-3-2H-benzotriazole-2, manufactured by basf corporation), methyl 3- (3- (2H-benzotriazol-2-yl) -5-tert-butyl-4-hydroxyphenyl) propionate/polyethylene glycol 300 (trade name "TINUVIN 1130", manufactured by basf corporation), 2- (2H-benzotriazol-2-yl) -P-cresol (trade name "TINUVIN P", manufactured by basf corporation), 2- (2H-benzotriazol-2-yl) -4, 6-bis (1-methyl-1-phenylethyl) phenol (trade name "TINUVIN 234"), manufactured by basf corporation), 2- [ 5-chloro-2H-benzotriazol-2-yl ] -4-methyl-6- (t-butyl) phenol (trade name "TINUVIN 326", manufactured by basf corporation), 2- (2H-benzotriazol-2-yl) -4, 6-di-t-pentylphenol (trade name "TINUVIN 328", manufactured by basf corporation), 2- (2H-benzotriazol-2-yl) -4- (1, 3-tetramethylbutyl) phenol (trade name "TINUVIN 329", manufactured by basf corporation), 2' -methylenebis [6- (2H-benzotriazol-2-yl) -4- (1, 3-tetramethylbutyl) phenol ] (trade name "TINUVIN 360", manufactured by basf corporation), reaction product of methyl 3- (3- (2H-benzotriazol-2-yl) -5-tert-butyl-4-hydroxyphenyl) propionate with polyethylene glycol 300 (trade name "TINUVIN 213", manufactured by Basv Co., ltd.), 2- (2H-benzotriazol-2-yl) -6-dodecyl-4-methylphenol (trade name "TINUVIN 571", manufactured by Basv Co., ltd.), 2- [ 2-hydroxy-3- (3, 4,5, 6-tetrahydrophthalimide-methyl) -5-methylphenyl ] benzotriazole (trade name "Sumisorb", manufactured by Sumitomo chemical Co., ltd.), 2- (3-tert-butyl-2-hydroxy-5-methylphenyl) -5-chloro-2H-benzotriazole (trade name "SEESORB", manufactured by SHIPRO KASEI KAISHA, LTD.), 2- (2H-benzotriazol-2-yl) -4-methyl-6- (3, 4,5, 6-tetrahydrophthalimide-methyl) phenol (trade name "35706", manufactured by SHIPRO KASEI KAISHA, LTD.), 2- (4-benzoyloxy-2-hydroxy-phenyl) -5-chloro-2H-benzotriazole (trade name "35703", manufactured by Sumitomo chemical Co., ltd.) (trade name "4912H-498") 2-tert-butyl-6- (5-chloro-2H-benzotriazol-2-yl) -4-methylphenol (trade name "KEMISORB-3", chemipro KASEI KAISHA, LTD.), 2' -methylenebis [6- (2H-benzotriazol-2-yl) -4-tert-octylphenol ] (trade name "ADK STAB LA-31", manufactured by ADEKA Co., ltd.), 2- (2H-benzotriazol-2-yl) -p-cellulose (trade name "ADK STAB LA-32", manufactured by ADEKA Co., ltd.), 2- (5-chloro-2H-benzotriazol-2-yl) -6-tert-butyl-4-methylphenol (trade name "ADK STAB LA-36", manufactured by ADEKA Co., ltd.), and the like.

The ultraviolet absorber may be a dye or a pigment. Examples of pigments include azo pigments, phthalocyanine pigments, anthraquinone pigments, lake pigments, perylene pigments, perinone pigments, quinacridone pigments, thioindigo pigments, dioxazine pigments, isoindolinone pigments, quinophthalone pigments, and the like. Examples of the dye include azo dyes, phthalocyanine dyes, anthraquinone dyes, carbonyl dyes, indigo dyes, quinone imine dyes, methine dyes, quinoline dyes, and nitro dyes.

The molecular weight of the compound constituting the ultraviolet absorber is preferably 100 to 1500, more preferably 200 to 1200, and even more preferably 200 to 1000.

The maximum absorption wavelength of the ultraviolet absorber is preferably 300nm to 450nm, more preferably 320nm to 400nm, and still more preferably 330nm to 380nm. The difference between the maximum absorption wavelength of the ultraviolet absorber and the maximum absorption wavelength of the photopolymerization initiator is preferably 10nm or more, more preferably 25nm or more.

The content ratio of the ultraviolet absorber is preferably 1 to 50 parts by weight, more preferably 5 to 20 parts by weight, based on 100 parts by weight of the base polymer in the UV-absorbing light-heat conversion layer.

(Pressure sensitive adhesive)

Examples of the pressure-sensitive adhesive include acrylic adhesives, rubber adhesives, vinyl alkyl ether adhesives, silicone adhesives, polyester adhesives, polyamide adhesives, urethane adhesives, and styrene-diene block copolymer adhesives. Among them, an acrylic adhesive or a rubber adhesive is preferable, and an acrylic adhesive is more preferable. The above-mentioned binders may be used singly or in combination of 2 or more.

Examples of the acrylic pressure-sensitive adhesive include an acrylic pressure-sensitive adhesive comprising an acrylic polymer (homopolymer or copolymer) using 1 or 2 or more alkyl (meth) acrylates as a monomer component, as a base polymer. Examples of the acrylic polymer include homopolymers and copolymers of hydrocarbon group-containing (meth) acrylates such as alkyl (meth) acrylates, cycloalkyl (meth) acrylates, aryl (meth) acrylates, and the like; copolymers of the hydrocarbon group-containing (meth) acrylate with other copolymerizable monomers, and the like. Specific examples of the alkyl (meth) acrylate include (C1-20) acrylates such as methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, sec-butyl (meth) acrylate, tert-butyl (meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, nonyl (meth) acrylate, isononyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, undecyl (meth) acrylate, dodecyl (meth) acrylate, tridecyl (meth) acrylate, tetradecyl (meth) acrylate, pentadecyl (meth) acrylate, hexadecyl (meth) acrylate, heptadecyl (meth) acrylate, octadecyl (meth) acrylate, nonadecyl (meth) acrylate, and eicosyl (meth) acrylate. Among them, alkyl (meth) acrylates having a linear or branched alkyl group having 4 to 18 carbon atoms can be preferably used.

Examples of the other copolymerizable monomer include carboxyl group-containing monomers, acid anhydride monomers, hydroxyl group-containing monomers, glycidyl group-containing monomers, sulfonic acid group-containing monomers, phosphoric acid group-containing monomers, functional group-containing monomers such as acrylamide and acrylonitrile, and the like. Examples of the carboxyl group-containing monomer include acrylic acid, methacrylic acid, carboxyethyl (meth) acrylate, carboxypentyl (meth) acrylate, itaconic acid, maleic acid, fumaric acid, and crotonic acid. Examples of the acid anhydride monomer include maleic anhydride and itaconic anhydride. Examples of the hydroxyl group-containing monomer 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 the glycidyl group-containing monomer include glycidyl (meth) acrylate and methyl glycidyl (meth) acrylate. Examples of the sulfonic acid group-containing monomer include styrene sulfonic acid, allyl sulfonic acid, 2- (meth) acrylamide-2-methylpropanesulfonic acid, (meth) acrylamide propane sulfonic acid, sulfopropyl (meth) acrylate, and (meth) acryloxynaphthalene sulfonic acid. Examples of the phosphate group-containing monomer include 2-hydroxyethyl acryloyl phosphate. As the acrylamide, for example, N-acryloylmorpholine can be mentioned. These may be used alone or in combination of 2 or more. The content of the structural unit derived from the above-mentioned copolymerizable monomer is preferably 60 parts by weight or less, more preferably 40 parts by weight or less, based on 100 parts by weight of the base polymer.

Examples of the rubber-based adhesive include a rubber-based adhesive comprising the following rubber as a base polymer: natural rubber; synthetic rubbers such as polyisoprene rubber, styrene-butadiene (SB) rubber, styrene-isoprene (SI) rubber, styrene-isoprene-styrene block copolymer (SIs) rubber, styrene-butadiene-styrene block copolymer (SBs) rubber, styrene-ethylene-butylene-styrene block copolymer (SEBS) rubber, styrene-ethylene-propylene-styrene block copolymer (SEPS) rubber, styrene-ethylene-propylene block copolymer (SEP) rubber, reclaimed rubber, butyl rubber, polyisobutylene, and modified products thereof, and the like.

The pressure sensitive adhesives described above may contain any suitable additives as desired. Examples of the additives include a crosslinking agent, a tackifier (for example, a rosin-based tackifier, a terpene-based tackifier, and a hydrocarbon-based tackifier), a plasticizer (for example, a trimellitate-based plasticizer and a pyromellitic plasticizer), a pigment, a dye, an anti-aging agent, a conductive material, an antistatic agent, a light stabilizer, a peeling regulator, a softener, a surfactant, a flame retardant, and an antioxidant.

(Active energy ray-curable adhesive)

In one embodiment, as the active energy ray-curable adhesive, an active energy ray-curable adhesive (A1) containing a base polymer as a parent agent and an active energy ray-reactive compound (monomer or oligomer) is used. In another embodiment, an active energy ray-curable adhesive (A2) containing an active energy ray-reactive polymer as a base polymer is used. In one embodiment, the base polymer has a functional group that can be cleaved by a photopolymerization initiator. Examples of the functional group include a functional group having a carbon-carbon double bond. Examples of the active energy ray include gamma rays, ultraviolet rays, visible rays, infrared rays (hot rays), radio waves, alpha rays, beta rays, electron beams, plasma streams, ionizing rays, and particle beams. Preferably ultraviolet light.

Examples of the base polymer used for the adhesive (A1) include rubber-based polymers such as natural rubber, polyisobutylene rubber, styrene-butadiene rubber, styrene-isoprene-styrene block copolymer rubber, reclaimed rubber, butyl rubber, polyisobutylene rubber, and nitrile rubber (NBR); an organosilicon-based polymer; acrylic polymers, and the like. These polymers may be used singly or in combination of 2 or more. Among them, acrylic polymers are preferable.

Examples of the acrylic polymer include homopolymers and copolymers of hydrocarbon group-containing (meth) acrylates such as alkyl (meth) acrylates, cycloalkyl (meth) acrylates, aryl (meth) acrylates, and the like; copolymers of the hydrocarbon group-containing (meth) acrylate with other copolymerizable monomers, and the like. Specific examples of the alkyl (meth) acrylate include (C1-20) acrylates such as methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, sec-butyl (meth) acrylate, tert-butyl (meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, nonyl (meth) acrylate, isononyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, undecyl (meth) acrylate, dodecyl (meth) acrylate, tridecyl (meth) acrylate, tetradecyl (meth) acrylate, pentadecyl (meth) acrylate, hexadecyl (meth) acrylate, heptadecyl (meth) acrylate, octadecyl (meth) acrylate, nonadecyl (meth) acrylate, and eicosyl (meth) acrylate. Among them, alkyl (meth) acrylates having a linear or branched alkyl group having 4 to 18 carbon atoms can be preferably used.

The acrylic polymer may contain structural units derived from a multifunctional monomer. Examples of the polyfunctional monomer 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., poly (meth) glycidyl acrylate), polyester (meth) acrylate, and urethane (meth) acrylate. These may be used alone or in combination of 2 or more. The content of the structural unit derived from the polyfunctional monomer is preferably 40 parts by weight or less, more preferably 30 parts by weight or less, based on 100 parts by weight of the base polymer.

The weight average molecular weight of the acrylic polymer is preferably 10 to 300 tens of thousands, more preferably 20 to 200 tens of thousands. The weight average molecular weight can be determined by GPC (solvent: THF).

Examples of the active energy ray-reactive compound that can be used for the binder (A1) include photoreactive monomers or oligomers having a polymerizable carbon-carbon multiple bond-containing functional group such as an acryl group, a methacryl group, a vinyl group, an allyl group, and an acetylene group. Specific examples of the photoreactive monomer include esters of (meth) acrylic acid and polyhydric alcohols such as trimethylolpropane tri (meth) acrylate, tetramethylolmethane tetra (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol monohydroxypenta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, 1, 4-butanediol di (meth) acrylate, 1, 6-hexanediol di (meth) acrylate, and polyethylene glycol di (meth) acrylate; multifunctional urethane (meth) acrylates; epoxy (meth) acrylates; oligomeric ester (meth) acrylates, and the like. Monomers such as methacryloyl isocyanate, 2-methacryloyloxyethyl isocyanate (ethyl methacrylate), and m-isopropenyl- α, α -dimethylbenzyl isocyanate can also be used. Specific examples of the photoreactive oligomer include dimers to pentamers of the above monomers. The molecular weight of the photoreactive oligomer is preferably 100 to 3000.

Further, as the active energy ray-reactive compound, monomers such as epoxidized butadiene, glycidyl methacrylate, acrylamide, vinyl siloxane, and the like can be used; or an oligomer composed of the monomer.

In the binder (A1), the content of the active energy ray-reactive compound is preferably 0.1 to 500 parts by mass, more preferably 5 to 300 parts by mass, and particularly preferably 40 to 150 parts by mass, based on 100 parts by mass of the base polymer.

Examples of the active energy ray-reactive polymer (base polymer) included in the binder (A2) include polymers having a carbon-carbon multiple bond-containing functional group such as an acryl group, a methacryl group, a vinyl group, an allyl group, and an acetylene group. Specific examples of the active energy ray-reactive polymer include polymers composed of polyfunctional (meth) acrylates; a photocationic polymerizable polymer; cinnamoyl-containing polymers such as polyvinyl cinnamate; diazotized amino novolac resins; polyacrylamide, and the like.

In one embodiment, an active energy ray-reactive polymer is used, which is formed by introducing an active energy ray-polymerizable carbon-carbon multiple bond into a side chain, a main chain and/or a main chain end of the acrylic polymer. Examples of the method for introducing a radiation polymerizable carbon-carbon double bond into an acrylic polymer include the following methods: an acrylic polymer is obtained by copolymerizing a raw material monomer containing a monomer having a predetermined functional group (functional group 1), and then a compound having a predetermined functional group (functional group 2) capable of reacting with and bonding to the functional group 1 and a radiation polymerizable carbon-carbon double bond is subjected to a condensation reaction or an addition reaction with the acrylic polymer while maintaining the radiation polymerization of the carbon-carbon double bond.

Examples of the combination of the 1 st functional group and the 2 nd functional group include a carboxyl group and an epoxy group, an epoxy group and a carboxyl group, a carboxyl group and an aziridine group, an aziridine group and a carboxyl group, a hydroxyl group and an isocyanate group, and an isocyanate group and a hydroxyl group. Among these combinations, a combination of a hydroxyl group and an isocyanate group and a combination of an isocyanate group and a hydroxyl group are preferable from the viewpoint of easiness of reaction tracking. In addition, since it is technically difficult to produce a polymer having an isocyanate group with high reactivity, it is more preferable that the 1 st functional group on the acrylic polymer side is a hydroxyl group and the 2 nd functional group is an isocyanate group from the viewpoint of easiness in producing or obtaining an acrylic polymer. In this case, examples of the isocyanate compound having both a radiation polymerizable carbon-carbon double bond and an isocyanate group as the 2 nd functional group include methacryloyl isocyanate, 2-methacryloyloxyethyl isocyanate, and m-isopropenyl- α, α -dimethylbenzyl isocyanate. The acrylic polymer having the 1 st functional group preferably contains a structural unit derived from the hydroxyl group-containing monomer, and a structural unit derived from an ether compound such as 2-hydroxyethyl vinyl ether, 4-hydroxybutyl vinyl ether, diethylene glycol monovinyl ether, and the like is also preferable.

The binder (A2) may further contain the active energy ray-reactive compound (monomer or oligomer).

The active energy ray-curable adhesive may contain a photopolymerization initiator.

As the photopolymerization initiator, any appropriate initiator may be used. Examples of the photopolymerization initiator include α -ketol compounds such as 4- (2-hydroxyethoxy) phenyl (2-hydroxy-2-propyl) ketone, α -hydroxy- α, α' -dimethyl acetophenone, 2-methyl-2-hydroxy propiophenone, and 1-hydroxycyclohexyl phenyl ketone; acetophenone compounds such as methoxyacetophenone, 2-dimethoxy-2-phenylacetophenone, 2-diethoxyacetophenone, and 2-methyl-1- [4- (methylthio) -phenyl ] -2-morpholinopropane-1-one; benzoin ether compounds such as benzoin ethyl ether, benzoin isopropyl ether, anisoin methyl ether, and the like; ketal compounds such as benzil dimethyl ketal; aromatic sulfonyl chloride compounds such as 2-naphthalenesulfonyl chloride; photoactive oxime compounds such as 1-benzophenone-1, 1-propanedione-2- (O-ethoxycarbonyl) oxime; benzophenone-based 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; acyl phosphine oxides; acyl phosphonates and the like. The amount of the photopolymerization initiator to be used may be set to any appropriate amount.

In one embodiment, the active energy ray-curable adhesive may contain a photosensitizer.

Preferably, the active energy ray-curable adhesive contains a crosslinking agent. Examples of the crosslinking agent 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.

The content of the crosslinking agent is preferably 0.01 to 20 parts by weight based on 100 parts by weight of the base polymer of the adhesive.

In one embodiment, an epoxy-based crosslinking agent is preferably used. Examples of the epoxy-based crosslinking agent include N, N, N ', N' -tetraglycidyl-meta-xylylenediamine, diglycidyl aniline, 1, 3-bis (N, N-glycidylaminomethyl) cyclohexane (product of Mitsubishi gas chemical Co., ltd., "TETRAD C"), 1, 6-hexanediol diglycidyl ether (product of Kabushiki chemical Co., ltd., "Epoligo 1600"), neopentyl glycol diglycidyl ether (product of Kaisha chemical Co., ltd., "Epoligo 1500 NP"), ethylene glycol diglycidyl ether (product of Kaisha chemical Co., ltd., "Epoligo 40E"), propylene glycol diglycidyl ether (product of Kaisha chemical Co., ltd., "Epoligo 70P"), polyethylene glycol diglycidyl ether (product of Japanese fat type Co., product of Japanese fat type chemical Co., ltd., "EPIOLE-400"), polypropylene glycol diglycidyl ether (product of Japanese fat type chemical Co., product of Japanese fat type chemical Co., ltd., "EPIOLP-200"), sorbitol polyglycidyl ether (product of Japanese polyglycidyl type polyester, de-Nagase ChemteX Corporation, product of DEC-32611-glycidyl ether, product of Japanese polyglycidyl, product of DEC-32-glycidyl ether, product of DEC-32, and triglycidyl-2, polyglycidyl triglycidyl ether (product of De-2-glycidyl triglycidyl, product of De-2-glycidyl triglycidyl) and triglycidyl isocyanurate Resorcinol diglycidyl ether, bisphenol S-diglycidyl ether, and epoxy resins having 2 or more epoxy groups in the molecule. The content of the epoxy-based crosslinking agent may be set to any appropriate amount according to the desired properties, and is typically 0.01 to 10 parts by weight, more preferably 0.05 to 7 parts by weight, based on 100 parts by weight of the base polymer.

In one embodiment, an isocyanate-based crosslinking agent is preferably used. Specific examples of the isocyanate-based crosslinking agent include: lower aliphatic polyisocyanates such as butylene diisocyanate and hexamethylene diisocyanate; alicyclic isocyanates such as cyclopentylene diisocyanate, cyclohexylene diisocyanate and isophorone diisocyanate; aromatic isocyanates such as 2, 4-toluene diisocyanate, 4' -diphenylmethane diisocyanate and xylylene diisocyanate; an isocyanate adduct such as trimethylolpropane/toluene diisocyanate trimer adduct (trade name "Coronate L" manufactured by Japanese polyurethane Industrial Co., ltd.), trimethylolpropane/hexamethylene diisocyanate trimer adduct (trade name "Coronate HL" manufactured by Japanese polyurethane Industrial Co., ltd.), and isocyanurate of hexamethylene diisocyanate (trade name "Coronate HX" manufactured by Japanese polyurethane Industrial Co., ltd.). It is preferable to use a crosslinking agent having 3 or more isocyanate groups. The content of the isocyanate-based crosslinking agent may be set to any appropriate amount according to the desired properties, and is typically 0.1 to 20 parts by weight, more preferably 0.5 to 10 parts by weight, based on 100 parts by weight of the base polymer.

The active energy ray-curable adhesive may further contain any appropriate additive as required. Examples of the additives include active energy ray polymerization accelerators, radical scavengers, tackifiers, plasticizers (e.g., trimellitate plasticizers, pyromellitic plasticizers, etc.), pigments, dyes, fillers, anti-aging agents, conductive materials, antistatic agents, ultraviolet absorbers, light stabilizers, peeling regulators, softeners, surfactants, flame retardants, antioxidants, and the like.

B-2 photo-thermal conversion layer capable of absorbing IR light

In one embodiment, a light-to-heat conversion layer capable of absorbing IR light (hereinafter, also referred to as an IR-absorbing light-to-heat conversion layer) is formed. In one embodiment, the release operation may be performed using an IR laser for the adhesive sheet provided with the IR-absorbing light-heat conversion layer. The transmittance of light having a wavelength of 1032nm of the IR-absorbing photothermal conversion layer is 50% or less, more preferably 40% or less, still more preferably 35% or less, and most preferably 0%. The IR-absorbing photothermal conversion layer may be a layer capable of further absorbing ultraviolet light, in which case not only the peeling operation can be performed by an IR laser but also the peeling operation can be performed by a UV laser.

In one embodiment, the IR-absorbing light-heat conversion layer is formed of a resin film. In one embodiment, as the resin film, a colored film containing a predetermined dye (pigment or dye) so as to absorb IR light of a predetermined wavelength may be used. The colored film as the IR-absorbing light-heat conversion layer may be a film (for example, a single-layer film) containing a pigment in a resin, or may be a film formed of a layer (for example, a print layer) containing a predetermined pigment and a resin layer. When the pigment-containing layer is formed, the pigment-containing layer is preferably adjacent to the thermal decomposition layer. As the pigment, any suitable pigment may be used in any suitable blending amount as long as it imparts IR light absorbability. Examples of the coloring matter include carbon black, cesium tungsten oxide, lanthanum hexaboride, tin-doped indium oxide, antimony-doped tin oxide, cyanine compound, phthalocyanine compound, dithiol metal complex, naphthoquinone compound, diimmonium compound, and azo compound. Examples of the resin constituting the resin film include polyimide-based resins, polyethylene terephthalate-based resins, polyamide-based resins, polyether ether ketone-based resins, polyethylene naphthalate-based resins, acrylic-based resins, and epoxy-based resins. Among them, polyimide-based resins or polyethylene terephthalate-based resins are preferable. Further, as the IR-absorbing light-heat conversion layer, a colored metal film (for example, a metal film provided with a colored print layer) may be used. The method of forming the printed layer is as described above.

C. thermal decomposition layer

The weight loss temperature of the thermal decomposition layer at 5% is preferably 250 to 400 ℃, more preferably 280 to 370 ℃. When the content is within such a range, the effects of the present invention described above become remarkable. The 5% weight loss temperature of the thermal decomposition layer can be adjusted by, for example, the type/structure of the resin (base polymer of the binder) constituting the thermal decomposition layer, the presence/absence of the additive, the type, and the like. When the 5% loss temperature is too low, that is, when the heat resistance is too low, there is a possibility that excessive decomposition occurs in the entire thermally decomposed layer upon irradiation with laser light, which hinders separation of the electronic component from the support.

The gel fraction of the thermal decomposition layer is preferably 70% or more, more preferably 80% to 99%, and still more preferably 85% to 97%. If the amount is within this range, removal of the thermal decomposition layer as a residue on the support after the electronic component is separated from the support becomes significantly easy. More specifically, when the thermally decomposed layer is heated even by the laser irradiation for heating the photothermal conversion layer, the thermally decomposed product of the thermally decomposed layer may be burned on the support, and conventionally, the recovery of the clean support may be troublesome, but by setting the gel fraction of the thermally decomposed layer to the above range, the removal of the thermally decomposed layer is significantly easy. The thermal decomposition layer may be removed using an organic solvent such as toluene. The gel fraction of the thermally decomposed layer can be controlled by adjusting the composition of the base polymer constituting the thermally decomposed layer, the kind and content of the crosslinking agent added to the thermally decomposed layer, the kind and content of the thickener, and the like. The gel fraction was measured as follows.

About 0.5g of the thermally decomposed layer (weight of the sample) was sampled and precisely weighed, and the sample was wrapped with a mesh sheet (trade name "NTF-1122", manufactured by Nito Denko Co., ltd.) and immersed in 50ml of toluene at room temperature (25 ℃ C.) for 1 week. Then, the solvent-insoluble component (the content of the mesh sheet) was taken out from toluene, dried at 130℃for about 2 hours, and the dried solvent-insoluble component (the weight after impregnation/drying) was weighed, and the gel fraction (weight%) was calculated from the following formula (a).

Gel fraction (% by weight) = [ (weight after impregnation/drying)/(weight of sample) ]. Times.100 (a)

The tensile elastic modulus of the thermal decomposition layer at 25℃is preferably 0.05MPa to 1GPa, more preferably 0.1MPa to 300MPa. If the amount is within this range, the thermally decomposed layer as a residue on the support can be easily removed after the electronic component is separated from the support. For example, the thermal decomposition layer may be swelled, and most of the thermal decomposition layer as a residue may be removed at the same time.

The thickness of the thermal decomposition layer is preferably 10 μm to 200. Mu.m, more preferably 20 μm to 150. Mu.m, still more preferably 30 μm to 100. Mu.m.

In one embodiment, the transmittance of light having a wavelength of 355nm of the thermal decomposition layer is 80% or more, more preferably 82% to 98%, and still more preferably 85% to 97%. If the amount is within this range, the laser light can be preferably made to reach the photothermal conversion layer at the time of peeling by UV laser irradiation, and peeling at the interface between the photothermal conversion layer and the photothermal conversion layer can be promoted.

In one embodiment, the transmittance of light having a wavelength of 1032nm of the thermal decomposition layer is 80% or more, more preferably 85% to 98%, and still more preferably 90% to 96%. If the amount is within this range, the laser light can be preferably made to reach the photothermal conversion layer at the time of peeling by the IR laser irradiation, and peeling at the interface between the photothermal conversion layer and the photothermal conversion layer can be promoted.

In one embodiment, the thermal decomposition layer comprises a pressure sensitive adhesive. As the pressure-sensitive adhesive, the pressure-sensitive adhesive described in item B above can be exemplified.

D. adhesive layer (other layers)

As described above, in one embodiment, the pressure-sensitive adhesive layer may be disposed on the surface of the photothermal conversion layer opposite to the pyrolytic layer. The adhesive layer comprises any suitable adhesive. For example, the pressure-sensitive adhesive described above is contained. In one embodiment, as the adhesive contained in the adhesive layer, a heat-resistant adhesive is used. By providing the adhesive layer composed of the heat-resistant adhesive, scorching (residual glue) on the work (device) can be suppressed when the laser light is irradiated. In the present specification, the heat-resistant adhesive means an adhesive having a predetermined adhesive force in an environment of 260 ℃. The heat-resistant adhesive can be preferably used without residual glue in an environment of 260 ℃. Preferably, the heat-resistant adhesive contains an acrylic resin, a silicone resin, or the like as a base polymer.

E. method for producing adhesive sheet

The adhesive sheet of the present invention may be manufactured by any suitable method. The pressure-sensitive adhesive sheet of the present invention can be formed by, for example, coating a composition for forming a thermal decomposition layer (for example, a pressure-sensitive adhesive) on a resin film serving as a photothermal conversion layer. The pressure-sensitive adhesive sheet may be obtained by bonding a thermal decomposition layer formed on another substrate to the photothermal conversion layer. The pressure-sensitive adhesive sheet may be formed by laminating a photothermal conversion layer formed by applying a composition for forming a photothermal conversion layer on a predetermined substrate and a pyrolytic layer formed by laminating a composition for forming a pyrolytic layer on another substrate. As the coating method, various methods such as bar coater coating, air knife coating, gravure reverse coating, reverse roll coating, die lip coating, die coating, dip coating, offset printing, flexography, screen printing, and the like can be employed. When the composition for forming a photothermal conversion layer contains an active energy ray-reactive compound, the coating layer of the composition for forming a photothermal conversion layer may be irradiated with active energy rays such as ultraviolet rays. The irradiation conditions may be any suitable conditions depending on the composition of the composition for forming a photothermal conversion layer.

F. Use of adhesive sheet for temporary fixation of electronic component

In one embodiment, as described above, the adhesive sheet 100 is disposed on the support 200 so that the thermal decomposition layer side becomes the support 200 side, and further, the electronic component 300 as the work is disposed on the side of the adhesive sheet 100 opposite to the support 200 (fig. 2 (a)), and the adhesive sheet 100 disposed on the support 200 is irradiated with laser light, whereby the light-heat conversion layer 10 generates heat, and the generated heat propagates to the adjacent thermal decomposition layer 20, whereby the thermal decomposition layer 20 starts to decompose locally at the interface with the light-heat conversion layer 10, for example, (b) of fig. 2), and as a result, the interface with the light-heat conversion layer 10 of the thermal decomposition layer 20 changes in shape to lose adhesiveness, and the light-heat conversion layer 10 is peeled off from the support 200 (fig. 2 (c)); next, the thermally decomposed layer 20 on the support 200 is removed (for example, impregnation removal with toluene), whereby the clean support 200 can be recovered with the residue suppressed (fig. 2 (d)).

Examples of the electronic component to be processed include a semiconductor wafer, a semiconductor package, a semiconductor chip, an insulating material for a circuit board, a chip mounting film, and a ceramic material. The number of the electronic components may be plural or 1.

The electronic component may be attached to the pressure-sensitive adhesive sheet via, for example, a pressure-sensitive adhesive layer disposed on the side of the photothermal conversion layer opposite to the pyrolytic layer.

After the electronic component is disposed on the pressure-sensitive adhesive sheet (that is, in the state of fig. 2 (a)), a predetermined process may be performed on the electronic component. Examples of the treatment include polishing, dicing, die bonding, wire bonding, etching, vapor deposition, molding, rewiring, through-hole formation, and device surface protection.

As the laser, any laser having a suitable wavelength may be used depending on the structure of the adhesive sheet. The conditions for laser irradiation may be any suitable conditions depending on the structure of the pressure-sensitive adhesive sheet. In one embodiment, a UV laser is used as the laser. The wavelength of the UV laser is preferably 150nm to 380nm, more preferably 240nm to 360nm. The output of the UV laser is, for example, 0.1W to 2.0W. In another embodiment, an IR laser is used as the laser. The wavelength of the IR laser is preferably 800nm to 10600nm, more preferably 900nm to 1200nm. The output of the IR laser is, for example, 0.01W to 10W.

Examples

Hereinafter, the present invention will be described more specifically by way of examples, but the present invention is not limited to these examples. The evaluation method in the examples is as follows. In the examples, "parts" and "%" are weight basis unless otherwise specified.

[ Evaluation ]

(1) Tensile elastic modulus of photothermal conversion layer at 200 DEG C

The photothermal conversion layers obtained in examples and comparative examples were used as samples, and the tensile elastic modulus at 200℃was measured using a dynamic viscoelasticity measuring apparatus (trade name "RSA-3", manufactured by TA Instrument Co., ltd.) under the following conditions.

Measuring frequency: 1Hz

Strain: 0.05%

Distance between chucks: 20mm of

Sample width: 10mm of

At a heating rate of 5 ℃ per minute from 0 ℃ to 250 DEG C

(2) Tensile elastic modulus of the thermal decomposition layer at 25 DEG C

The thermal decomposition layers obtained in examples and comparative examples were used as samples, and the tensile elastic modulus at 25℃was measured using a dynamic viscoelasticity measuring apparatus (trade name "RSA-3" manufactured by TA Instrument Co., ltd.) under the same conditions as in (1) above.

(3) 5% Weight loss temperature of photothermal conversion layer and thermal decomposition layer

The photothermal conversion layer and the thermal decomposition layer obtained in examples and comparative examples were used as evaluation samples.

A differential thermal analyzer (trade name "Discovery TGA" manufactured by TA Instruments corporation) was used to raise the temperature: 10 ℃/min, under N ₂ atmosphere, flow: 25 ml/min, the temperature at which the weight loss is 5% was determined.

Specifically, the evaluation sample was set up in the analysis device at about 0.01g, and the temperature was temporarily raised from 20 ℃ to 110 ℃ at the temperature raising rate, and the temperature was lowered from 110 ℃ to 20 ℃ at the temperature lowering rate of 10 ℃/min, whereby the influence of the contained moisture was removed, and the weight loss of the evaluation sample was measured while raising the temperature again from 20 ℃ to 500 ℃ at the temperature raising rate. The temperature at which the weight loss was 5% was extracted from the obtained data.

(4) Light transmittance of photothermal conversion layer, thermal decomposition layer, and adhesive sheet

The photothermal conversion layer, the thermal decomposition layer and the adhesive sheet obtained in examples and comparative examples were used as evaluation samples.

The light transmittance in the wavelength region of 300nm to 2500nm was measured by being placed on a spectrophotometer (trade name "UV-VIS ultraviolet visible spectrophotometer SolidSpec3700", manufactured by Shimadzu corporation) so that the incident light was perpendicularly incident on each sample. Transmittance at wavelengths of 355nm and 1032nm of the extracted transmission spectrum.

(5) Adhesive layer side adhesion

The heat-decomposition layer side of the adhesive sheet was adhered and fixed to a stainless steel plate, and the adhesive layer was adhered to a polyethylene terephthalate film (trade name "Lumirror S10", thickness: 25 μm, manufactured by eastern co., ltd.) by using a method based on JIS Z0237: the adhesion to PET#25 on the pressure-sensitive adhesive layer side was measured by 2000 methods (lamination conditions: 1 round trip of a 2kg roller, stretching speed: 300 mm/min, peeling angle 180 °, measurement temperature: 23 ℃).

(6) Initial adhesion to glass (thermal decomposition layer side)

The thermally decomposed layer side of the adhesive sheet was adhered to glass by using a pressure sensitive adhesive sheet according to JIS Z0237: 2000 (lamination condition: 1 reciprocation of 2kg roller, stretching speed: 300 mm/min, peeling angle 180 °, measurement temperature: 23 ℃) the initial adhesion to glass on the thermally decomposed layer side of the adhesive sheet was measured. As the glass described above and the glass in the following evaluation (7), a glass slide made of Song-Lang Nitro and a non-tin surface of product No. S200423 (water edge mill 65 mm. Times.165 mm. Times.1.3 mmT) were used. The non-tin surface is grasped as a surface which is not developed by UV irradiation with a UV lamp.

(7) Evaluation of laser debonding

The adhesive layer side of the adhesive sheet obtained in examples and comparative examples was adhered to a thin glass (cover glass made of Song 'S nitro, rectangle No.1, trade name "C050701") having a width of 50mm, a length of 70mm and a thickness of 0.12mmt of a work such as a dummy semiconductor wafer by a hand press roll, the adhesive sheet was cut according to the size of the thin glass, and then the thermally decomposed layer side was laminated to a support (thick glass made of Song' S nitro, standard large-size white edge grinder No.2, trade name "S9112") having a width of 52mm, a length of 76mm and a thickness of 1.0mmt of a dummy light-transmitting support substrate by a hand press roll. Then, the laminate was put into an autoclave and heated to defoam (40 ℃ C., 5kgf, 10 minutes) to remove bubbles embedded in the laminate, thereby producing a laminate sample.

The produced laminate sample was irradiated with laser light from the support side, and subjected to laser debonding evaluation. Specifically, in the case of IR laser debonding evaluation, a wavelength of 1032nm and a beam diameter of aboutThe laser beam of (2) was scanned with pulses at a frequency of 25kHz at an output of 7.7W so as to have a pitch of about 80 μm. Alternatively, in the case of UV laser debonding evaluation, a line laser having a wavelength of 355nm, a beam width of about 10 μm, a beam length of about 1.5mm, and an energy density of 0.5J/cm ² was used to perform pulse scanning at a frequency of 10kHz with an output of 0.75W so that an overlap of about 10 μm in the width direction and about 0.2mm or more in the length direction was generated at intervals of the line center. After the laminate sample was irradiated with laser light of various corresponding wavelengths, the adhesion availability and adhesion-free portions of the thin glass (work) and the support were confirmed. The various lasers used are shown in table 1.

Regarding evaluation of the laser debonding property, in the debonding operation of the thin glass and the thick glass, the level at which debonding can be easily performed when 1 part of the outer peripheral portion of the laminate sample is floated by the cutter was good in debonding operation, the level at which the outer peripheral portion is floated by the cutter and finally debonded can be performed was Δ, and the level at which debonding cannot be performed even if the cutter is inserted into the outer peripheral portion and the thin glass (work) is broken was x.

(8) Evaluation of support recyclability

For the sample from which the thin glass and the thick glass can be separated in the laser debonding evaluation of (7), the recyclability evaluation of the support was performed. Specifically, the state of contamination on the support after laser debonding was visually observed, and the case where no residue that could not be removed and was visible to the naked eye remained after immersion in toluene at 25 ℃ for 2 hours was noted as good, and the case where residue was noted as x.

(9) Gel fraction of thermally decomposed layer

The thermal decomposition layers obtained in examples and comparative examples were used as evaluation samples, and about 0.5g of the thermal decomposition layer was precisely weighed and used as a sample (weight W1). The sample was wrapped in a porous polytetrafluoroethylene film (trade name "Nitoflon NTF 1122", manufactured by Nito electric Co., ltd., average pore size: 0.2 μm, porosity 75%, thickness 85 μm, weight W2) in a pouch shape, and the mouth was bound with a thread (weight W3). The pouch was immersed in 50mL of toluene and kept at room temperature (25 ℃) for 7 days, only the sol component in the adhesive layer was eluted out of the film, and then the pouch was taken out, toluene adhering to the outer surface was wiped off, and the pouch was dried at 130℃for 2 hours, and the weight (W4) of the pouch was measured. Then, the gel fraction was obtained by substituting each value into the following equation.

Gel fraction (%) = [ (W4-W2-W3)/W1 ] ×100

Production example 1 production of acrylic Polymer A

50 Parts by weight of butyl acrylate, 50 parts by weight of ethyl acrylate, 5 parts by weight of acrylic acid, 0.1 part by weight of 2-hydroxyethyl acrylate, 0.3 part by weight of trimethylolpropane triacrylate and 0.1 part by weight of benzoyl peroxide as a polymerization initiator were added to toluene, and then heated to 70℃to obtain a toluene solution of an acrylic polymer (polymer A).

Production example 2 production of acrylic Polymer B

After 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, the mixture was heated to 70℃to obtain an ethyl acetate solution of the acrylic polymer (polymer B).

Production example 3 production of acrylic Polymer C

After adding 30 parts by weight of 2-ethylhexyl acrylate, 70 parts by weight of methyl acrylate, 10 parts by weight of acrylic acid and 0.2 part by weight of benzoyl peroxide as a polymerization initiator to ethyl acetate, the mixture was heated to 70℃to obtain an ethyl acetate solution of an acrylic polymer (polymer C).

Production example 4 production of acrylic Polymer D

88.8 Parts by weight of 2-ethylhexyl acrylate, 11.2 parts by weight of 2-hydroxyethyl acrylate, and 0.2 part by weight of a polymerization initiator (trade name "NYPER BW" manufactured by Japanese fat & oil Co., ltd.) were mixed with toluene. The resulting mixture was polymerized at 60℃under a nitrogen gas stream to obtain an acrylic copolymer having a weight average molecular weight (Mw) of about 60 ten thousand.

An acrylic polymer D having a carbon-carbon double bond was prepared by adding 12 parts by weight of methacryloxyethyl isocyanate (MOI) and 0.06 parts by weight of butyltin dilaurate to a toluene solution containing 100 parts by weight of an acrylic copolymer, and subjecting the MOI to an addition reaction.

PREPARATION EXAMPLE 5 preparation of pressure sensitive adhesive

An adhesive was prepared by mixing an ethyl acetate solution of polymer B (polymer B:100 parts by weight) with 2 parts by weight of an epoxy-based crosslinking agent (trade name "TETRAD-C", manufactured by Mitsubishi gas chemical Co., ltd.). The composition of the adhesive is shown in table 1.

PREPARATION EXAMPLE 6 preparation of composition I (Binder I) for Forming thermally decomposed layer

A toluene solution of Polymer A (Polymer A:100 parts by weight) was mixed with 1 part by weight of an epoxy-based crosslinking agent (trade name "TETRAD-C", manufactured by Mitsubishi gas chemical Co., ltd.) to prepare a composition I for forming a thermally decomposed layer.

PREPARATION EXAMPLE 7 preparation of composition II (Binder II) for Forming a thermal decomposition layer

An ethyl acetate solution of polymer C (polymer A:100 parts by weight) was mixed with 1 part by weight of an epoxy-based crosslinking agent (trade name "TETRAD-C", manufactured by Mitsubishi gas chemical Co., ltd.) to prepare a composition II for forming a thermal decomposition layer.

PREPARATION EXAMPLE 8 preparation of composition III (Binder III) for Forming a thermal decomposition layer

A composition III for forming a thermal decomposition layer was prepared by mixing 1 part by weight of a toluene solution of Polymer A (100 parts by weight of Polymer A), 1 part by weight of an epoxy-based crosslinking agent (trade name "TETRAD-C" manufactured by Mitsubishi gas chemical Co., ltd.), 70 parts by weight of a UV oligomer (trade name "purple UV-1700B" manufactured by Mitsubishi chemical Co., ltd.), 30 parts by weight of a UV oligomer (trade name "purple UV-3000B" manufactured by Mitsubishi chemical Co., ltd.), and 0.5 part by weight of a photopolymerization initiator (trade name "Omnirad 127D" manufactured by BASF Co.).

PREPARATION EXAMPLE 9 composition I for Forming photothermal conversion layer

A composition I for forming a photothermal conversion layer was prepared by mixing 1 part by weight of a toluene solution of Polymer A (100 parts by weight of Polymer A), 1 part by weight of an epoxy-based crosslinking agent (trade name "TETRAD-C" manufactured by Mitsubishi gas Chemicals Co., ltd.), 70 parts by weight of a UV oligomer (trade name "ultraviolet UV-1700B" manufactured by Mitsubishi chemical Co., ltd.), 30 parts by weight of a UV oligomer (trade name "ultraviolet UV-3000B" manufactured by Mitsubishi chemical Co., ltd.), 0.5 part by weight of a photopolymerization initiator (trade name "Omnirad 127D" manufactured by BASF Co., ltd.), and 20 parts by weight of a reaction product of an ultraviolet absorber (2- (4, 6-bis (2, 4-dimethylphenyl) -1,3, 5-triazin-2-yl) -5-hydroxyphenyl) methyl ] ethylene oxide [ (C10-C16 (mainly C12-C13 alkoxy) and (trade name "TINU400", manufactured by BASF).

Example 1

The pressure-sensitive adhesive obtained in production example 5 was applied to one side of a polyimide film (trade name "Kapton 100H" thickness: 25 μm, manufactured by eastern dupont) as a photothermal conversion layer so that the thickness of the film became 10 μm after evaporation of the solvent (drying), and then dried, a pressure-sensitive adhesive layer was formed on the polyimide film, and a polyethylene terephthalate film (trade name "Cerapeel" thickness: 38 μm, manufactured by eastern dupont) having a silicone release agent-treated surface was laminated and bonded between rolls.

Next, the composition I for forming a thermal decomposition layer obtained in production example 6 was applied to a polyethylene terephthalate film (thickness: 75 μm) having a silicone release agent-treated surface so that the thickness thereof became 50 μm after evaporation (drying) of the solvent, and then dried, and laminated and bonded to the side of the polyimide film opposite to the pressure-sensitive adhesive layer between rolls.

Thus, an adhesive sheet (adhesive layer (pressure-sensitive adhesive layer)/photothermal conversion layer (polyimide film)/thermal decomposition layer) sandwiched by polyethylene terephthalate films having a silicone release agent treated surface was obtained.

The obtained adhesive sheet was subjected to the above evaluation. The results are shown in table 1.

Example 2

An adhesive sheet was obtained in the same manner as in example 1, except that the resin film (photothermal conversion layer) and the composition for forming a thermally decomposed layer described in table 1 were used and the thicknesses of the respective layers were as shown in table 1. The obtained adhesive sheet was subjected to the above evaluation. The results are shown in table 1.

The resin film "black printed PET (1)" used as the photothermal conversion layer was a polyethylene terephthalate film with a printed layer, and was a resin film having a light transmittance of 0% at a wavelength of 1032 nm.

Comparative example 1

The pressure-sensitive adhesive obtained in production example 5 was applied to one side of a polyethylene terephthalate film (trade name "LumirrorS", thickness: 25 μm) so that the thickness of the film became 10 μm after the solvent had evaporated (dried), and then dried, an adhesive layer was formed on the polyester terephthalate film, and a polyethylene terephthalate film (trade name "Cerapeel" thickness: 38 μm) having a silicone release agent-treated surface was laminated and bonded between rolls.

Then, the composition I for forming a photothermal conversion layer obtained in production example 6 was applied to a polyethylene terephthalate film (thickness: 75 μm) having a silicone release agent-treated surface so that the thickness thereof became 50 μm after evaporation (drying) of the solvent, and then dried, and then laminated on the opposite side of the polyester terephthalate film from the adhesive layer by lamination between rolls, and UV irradiation was performed under conditions of 1380mJ/cm ².

Thus, an adhesive sheet (adhesive layer (pressure-sensitive adhesive layer)/substrate layer/photothermal conversion layer) sandwiched by polyethylene terephthalate films having a silicone release agent treated surface was obtained. The pressure-sensitive adhesive sheet of this experimental example was a pressure-sensitive adhesive sheet having no thermal decomposition layer, and exhibited releasability by decomposition of the photothermal conversion layer by laser irradiation. In other words, the photothermal conversion layer also has the function of a thermal decomposition layer.

Comparative example 2

(Preparation of composition II for Forming photothermal conversion layer)

A composition II for forming a photothermal conversion layer was prepared by mixing 0.2 part by weight of a toluene solution of the acrylic polymer D obtained in production example 4 (polymer D:100 parts by weight), 0.2 part by weight of an isocyanate-based crosslinking agent (trade name "CORONATE L" manufactured by Tosoh Co., ltd., trade name "Omnirad 127D") 3 parts by weight of a photopolymerization initiator (trade name "TINUVIN 400", manufactured by BASF Co., ltd.), and 12.5 parts by weight of an ultraviolet absorber.

(Production of adhesive sheet)

Next, the composition II for forming a photothermal conversion layer was applied to a polyethylene terephthalate film (thickness: 75 μm) having a silicone release agent-treated surface so that the thickness thereof became 50 μm after the solvent had evaporated (dried), and then dried, and laminated and bonded between rolls to the side of the polyester terephthalate film opposite to the pressure-sensitive adhesive layer.

Comparative example 3

The pressure-sensitive adhesive obtained in production example 5 was applied to a polyethylene terephthalate film (thickness: 75 μm) having a silicone release agent-treated surface so that the thickness thereof became 10 μm after the solvent had evaporated (dried), and then dried, and an adhesive layer was formed on the polyethylene terephthalate film.

The composition II for forming a photothermal conversion layer obtained in comparative example 2 was applied to a polyethylene terephthalate film (trade name "Cerapeel" thickness: 38. Mu.m, manufactured by Toli Co., ltd.) having a silicone release agent-treated surface so that the thickness thereof became 30. Mu.m after evaporation (drying) of the solvent, and then dried, to form a photothermal conversion precursor layer on the polyethylene terephthalate film.

Next, the pressure-sensitive adhesive layer and the photothermal conversion precursor layer were laminated and bonded between rolls, and UV irradiation was performed at a condition of 500mJ/cm ² from the photothermal conversion precursor layer side, to obtain a laminate (pressure-sensitive adhesive layer/photothermal conversion layer) sandwiched by polyethylene terephthalate films having a silicone release agent treated surface.

The composition III for forming a thermal decomposition layer obtained in production example 8 was applied to a polyethylene terephthalate film (trade name "Cerapeel" thickness: 38 μm, manufactured by Toli Co., ltd.) having a silicone release agent-treated surface so that the thickness thereof became 50 μm after evaporation (drying), and then dried, whereby a thermal decomposition layer was formed on the polyethylene terephthalate film.

After the polyethylene terephthalate film with the silicone release agent-treated surface on the light-heat conversion layer side of the laminate was peeled off, the light-heat conversion layer and the thermal decomposition layer were laminated and bonded between rolls, to obtain an adhesive sheet (adhesive layer (pressure-sensitive adhesive layer)/light-heat conversion layer/thermal decomposition layer) sandwiched by the polyethylene terephthalate film with the silicone release agent-treated surface.

TABLE 1

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As is clear from table 1, the adhesive sheet for temporary fixing of electronic components of the present invention can satisfactorily separate the temporarily fixed electronic components from the support, and can easily remove the residue of the thermal decomposition layer on the support. In all of the examples, the separation of the electronic component was achieved by the interfacial separation of the thermal decomposition layer and the photothermal conversion layer, and as a result, it was considered that the above-described excellent effects were obtained. On the other hand, in the comparative examples, cohesive failure of the photothermal conversion layer occurred, and the effects of the present invention were not confirmed.

Description of the reference numerals

10. Photo-thermal conversion layer

20. Thermal decomposition layer

30. Adhesive layer

Adhesive sheet for temporary fixing 100 electronic parts

200. Support body

300. Electronic component

Claims

1. An adhesive sheet for temporarily fixing electronic components, comprising a photothermal conversion layer and a thermal decomposition layer directly disposed on the photothermal conversion layer,

The 5% weight loss temperature of the thermal decomposition layer is lower than the 5% weight loss temperature of the light-to-heat conversion layer.

2. The adhesive sheet for temporary fixation of an electronic component according to claim 1, wherein the light-to-heat conversion layer has a 5% weight loss temperature of 300 ℃ to 600 ℃.

3. The adhesive sheet for temporary fixation of an electronic component according to claim 1 or 2, wherein the 5% weight loss temperature of the thermal decomposition layer is 250 ℃ to 400 ℃.

4. The adhesive sheet for temporary fixation of an electronic component according to any one of claims 1 to 3, wherein the light transmittance of the photothermal conversion layer at 355nm is 50% or less.

5. The adhesive sheet for temporary fixation of an electronic component according to any one of claims 1 to 4, wherein the photothermal conversion layer is a resin film composed of a polyimide-based resin.

6. The adhesive sheet for temporary fixation of an electronic component according to any one of claims 1 to 5, wherein the transmittance of light having a wavelength of 355nm of the thermal decomposition layer is 80% or more.

7. The adhesive sheet for temporary fixation of an electronic component according to any one of claims 1 to 3, wherein the light transmittance of the photothermal conversion layer at a wavelength of 1032nm is 50% or less.

8. The adhesive sheet for temporary fixation of an electronic component according to any one of claims 1 to 3 and 7, wherein the light-heat conversion layer is a colored film.

9. The adhesive sheet for temporary fixation of an electronic component according to any one of claims 1 to 3, 7 and 8, wherein the transmittance of light having a wavelength of 1032nm of the thermal decomposition layer is 80% or more.

10. The adhesive sheet for temporary fixation of an electronic component according to any one of claims 1 to 9, wherein the gel fraction of the thermal decomposition layer is 70% or more.

11. The adhesive sheet for temporary fixation of an electronic component according to claim 1 to 10, wherein the tensile elastic modulus of the photothermal conversion layer at 200 ℃ is 5MPa to 2GPa.

12. The adhesive sheet for temporary fixation of an electronic component according to any one of claims 1 to 11, further comprising an adhesive layer,

The adhesive sheet for temporarily fixing an electronic component includes the adhesive layer, the photothermal conversion layer, and the thermal decomposition layer laminated in this order.

13. A method for treating an electronic component, comprising disposing an electronic component on the adhesive sheet according to any one of claims 1 to 12, and then subjecting the electronic component to a predetermined treatment.

14. The method for processing an electronic component according to claim 13, wherein the processing is polishing processing, dicing processing, die bonding, wire bonding, etching, vapor deposition, molding, rewiring formation, through-hole formation, or protection of a device surface.