Base material for adhesive sheet and adhesive sheet for electronic component processing

Abstract

The present invention provides a base material (1) for an adhesive sheet used in the processing of electronic components, which has: a polyester film (11) having a first film surface (11A) and a second film surface (11B), a first oligomer sealing layer (21), and a second oligomer sealing layer (22). The polyester film (11) has been annealed. The first oligomer sealing layer (21) and the second oligomer sealing layer (22) are each independently a cured film formed by curing a composition for forming an oligomer sealing layer containing a curable component. The first oligomer sealing layer (21) and the second oligomer sealing layer (22) substantially do not contain a filler. At least one of the root mean square height Rq1 of the first base material surface (21A) of the first oligomer sealing layer (21) and the root mean square height Rq2 of the second base material surface (22A) of the second oligomer sealing layer (22) is 0.031 μm or more.

Description

Technical Field

[0001] The present invention relates to a base material for an adhesive sheet and an adhesive sheet for electronic component processing. Background Art

[0002] Various characteristics are required for adhesive sheets used in the manufacturing process of semiconductor devices. For example, it is required to have a characteristic that does not contaminate the devices, components, and adherends used in the manufacturing process even after a process under high-temperature conditions is applied. In recent years, adhesive sheets have been used in processes under high-temperature conditions of 180°C or higher and 200°C or lower. It is known that in such high-temperature processes, for example, when a film with lower heat resistance and lower cost than a polyimide film (e.g., a film such as polyethylene terephthalate) is used as the base material of the adhesive sheet, the surface of the adherend is contaminated when the adhesive sheet is peeled off from the adherend after the process. The reason for such contamination is considered to be the precipitation of low-molecular-weight components (oligomers) contained in the resin film used as the base material onto the surface of the adherend. For example, when high-temperature conditions are applied in the process of resin-sealing a semiconductor element adhered to the adhesive layer of the adhesive sheet, the surface of the semiconductor element may be contaminated, resulting in defects in the semiconductor device.

[0003] As a technique for eliminating such defects, for example, Patent Document 1 describes an adhesive sheet having an oligomer sealing layer between the base material and the adhesive layer.

[0004] Prior Art Documents

[0005] Patent Documents

[0006] Patent Document 1: International Publication No. 2017 / 038917 Summary of the Invention

[0007] Problems to be Solved by the Invention

[0008] When laminating base materials for adhesive sheets on each other, so-called sticking sometimes occurs. For the adhesive sheet described in Patent Document 1, sticking sometimes occurs when multiple base materials for adhesive sheets are laminated and the oligomer sealing layers come into contact with each other. In addition, in a process under high-temperature conditions, the deformation of the adhesive sheet sometimes has an adverse effect on the adherend.

[0009] An object of the present invention is to provide a base material for an adhesive sheet and an adhesive sheet for electronic component processing including the same, which have excellent heat resistance, can prevent contamination of the surfaces of components, devices, adherends, etc. even after a process under high-temperature conditions is applied, can reduce the influence of the deformation of the adhesive sheet caused by high-temperature conditions, and can prevent sticking.

[0010] Means for Solving the Problems

[0011] According to one aspect of the present invention, a base material for an adhesive sheet used in the processing of electronic components can be provided. The base material for the adhesive sheet has: a polyester film having a first film surface and a second film surface opposite to the first film surface, a first oligomer sealing layer provided on the first film surface, and a second oligomer sealing layer provided on the second film surface. The polyester film has been annealed. The first oligomer sealing layer and the second oligomer sealing layer are each independently a cured film formed by curing an oligomer sealing layer-forming composition containing a curable component. The first oligomer sealing layer and the second oligomer sealing layer substantially do not contain a filler. At least one of the root mean square height Rq1 of the surface of the first oligomer sealing layer on the side opposite to the surface facing the first film surface and the root mean square height Rq2 of the surface of the second oligomer sealing layer on the side opposite to the surface facing the second film surface is 0.031 μm or more.

[0012] In the base material for an adhesive sheet according to one aspect of the present invention, it is preferable that the polyester film is a polyethylene terephthalate film.

[0013] In the base material for an adhesive sheet according to one aspect of the present invention, it is preferable that the thickness of the first oligomer sealing layer is 50 nm or more and 180 nm or less.

[0014] In the base material for an adhesive sheet according to one aspect of the present invention, it is preferable that the thickness of the second oligomer sealing layer is 50 nm or more and 180 nm or less.

[0015] According to one aspect of the present invention, an adhesive sheet for processing electronic components can be provided. The adhesive sheet has the base material for an adhesive sheet according to one aspect of the present invention described above and an adhesive layer. Among them, the adhesive layer is provided on at least one of the surface of the first oligomer sealing layer on the side opposite to the surface facing the first film surface and the surface of the second oligomer sealing layer on the side opposite to the surface facing the second film surface.

[0016] In the adhesive sheet for processing electronic components according to one aspect of the present invention, it is preferable that the adhesive layer contains an acrylic polymer, and the acrylic polymer contains a structural unit derived from a monomer having a nitrogen-containing functional group, and the nitrogen-containing functional group does not contain an N-H bond.

[0017] In the adhesive sheet for processing electronic components according to one aspect of the present invention, it is preferable that the proportion of the structural unit derived from the monomer having a nitrogen-containing functional group in the total mass of the acrylic polymer is 9% by mass or more and 15% by mass or less.

[0018] In the adhesive sheet for processing electronic components according to one aspect of the present invention, it is preferable that the adhesive layer contains a polymer of a polyvalent compound having an energy ray polymerizable functional group.

[0019] In the adhesive sheet for electronic component processing according to one embodiment of the present invention, it is preferable that the adhesive layer contains a compound having an unreacted energy ray-polymerizable functional group.

[0020] According to one embodiment of the present invention, it is possible to provide a base material for an adhesive sheet and an adhesive sheet for electronic component processing including the same, which have excellent heat resistance, can prevent contamination of the surfaces of members, devices, adherends, etc. even after a process under high temperature conditions, can reduce the influence caused by deformation of the adhesive sheet due to high temperature conditions, and can also prevent adhesion. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic cross-sectional view of a base material for an adhesive sheet according to one embodiment of the present invention.

[0022] Figure 2 It is a schematic cross-sectional view of an adhesive sheet for electronic component processing according to one embodiment of the present invention.

[0023] Figure 3 It is a schematic cross-sectional view of an adhesive sheet for electronic component processing according to one embodiment of the present invention.

[0024] SYMBOL DESCRIPTION

[0025] 1 ··· Base material for adhesive sheet

[0026] 2, 3 ··· Adhesive sheet

[0027] 11 ··· Polyester film

[0028] 11A ··· First film surface

[0029] 11B ··· Second film surface

[0030] 21 ··· First oligomer sealing layer

[0031] 22 ··· Second oligomer sealing layer

[0032] 30 ··· Adhesive layer

[0033] RL ··· Release sheet

[0034] RL1 ··· First release sheet

[0035] RL2 ··· Second release sheet DETAILED DESCRIPTION OF THE INVENTION

[0036] 〔First Embodiment〕

[0037] (Base material for adhesive sheet)

[0038] Figure 1 A schematic cross-sectional view of the base material 1 for an adhesive sheet according to this embodiment is shown.

[0039] The base material 1 for the adhesive sheet has a polyester film 11, a first oligomer sealing layer 21, and a second oligomer sealing layer 22.

[0040] The polyester film 11 has a first film surface 11A and a second film surface 11B on the side opposite to the first film surface 11A. In the base material 1 for the adhesive sheet, the first oligomer sealing layer 21 is laminated on the first film surface 11A, and the second oligomer sealing layer 22 is laminated on the second film surface 11B. Preferably, the first film surface 11A is covered with the first oligomer sealing layer 21, and the second film surface 11B is covered with the second oligomer sealing layer 22.

[0041] The shape of the base material 1 for the adhesive sheet can be any shape such as a sheet shape or a strip shape, for example.

[0042] (Polyester film)

[0043] The base material 1 for the adhesive sheet of the present embodiment includes the polyester film 11 between the first oligomer sealing layer 21 and the second oligomer sealing layer 22.

[0044] The polyester film 11 is an annealed polyester film obtained by annealing treatment.

[0045] Since the polyester film 11 is a film that has undergone annealing treatment, it has high heat resistance. Therefore, the heat resistance of the base material 1 for the adhesive sheet can be improved. For example, the thermal shrinkage rate of the base material 1 for the adhesive sheet under high temperature conditions can be reduced.

[0046] Regarding the thermal shrinkage rate of the annealed polyester film, for example, when the polyester film is heated at 190 °C for 1 hour, it is 3% or less in the MD (Machine Direction) and 1% or less in the TD (Transverse Direction). Preferably, it is 2% or less in the MD direction and 0.3% or less in the TD direction. The measurement of the thermal shrinkage rate can be carried out by the method described in the examples.

[0047] The polyester film 11 contains a polyester resin, and is more preferably made of a material mainly composed of a polyester resin. In this specification, a material mainly composed of a polyester resin means that the mass ratio of the polyester resin in the total mass of the materials constituting the polyester film 11 is 50% by mass or more. The mass ratio of the polyester resin in the total mass of the materials constituting the polyester film 11 is preferably 80% by mass or more, more preferably 90% by mass or more, and further preferably 99% by mass or more.

[0048] As the polyester resin, for example, it is preferably any resin selected from polyethylene terephthalate resin, polybutylene terephthalate resin, polyethylene naphthalate resin, polybutylene naphthalate resin, and copolymers of these resins, and more preferably polyethylene terephthalate resin.

[0049] As the polyester film 11, it is preferably a polyethylene terephthalate film or a polyethylene naphthalate film, and more preferably a polyethylene terephthalate film. In the case of a polyethylene terephthalate film, it is cheaper than a polyethylene terephthalate film, has high supply stability, and is easily obtained.

[0050] The oligomers contained in the polyester film are derived from polyester-forming monomers, dimers, trimers, etc.

[0051] From the viewpoint of dimensional stability during processing, the lower limit of the storage modulus of the polyester film 11 at 100 °C is preferably 1×10 7 Pa or more, and more preferably 1×10 8 Pa or more. From the viewpoint of processing adaptability, the upper limit of the storage modulus of the polyester film 11 at 100 °C is preferably 1×10 12 Pa or less. It should be noted that in this specification, the storage modulus of the substrate at 100 °C is the value of the storage modulus obtained based on a tensile test performed using a viscoelasticity measuring instrument at a frequency of 1 Hz. The substrate to be measured is cut into a width of 5 mm and a length of 20 mm, and the storage modulus at 100 °C is measured using a viscoelasticity measuring instrument (manufactured by TA Instruments, DMAQ800) in a tensile mode at a frequency of 1 Hz.

[0052] At least one of the first film surface 11A and the second film surface 11B can be independently subjected to at least any one surface treatment such as a primer treatment, a corona treatment, and a plasma treatment. When such a surface treatment is performed, the adhesion between the polyester film surface and the oligomer sealing layer can be improved.

[0053] The root mean square height Rq of the first film surface 11A A and the root mean square height Rq of the second film surface 11B B At least one of them is preferably 0.03 μm or more, and more preferably 0.035 μm or more. The root mean square heights Rq A and Rq B can be the same value as each other or different values. When the root mean square height is 0.03 μm or more, it is easy to control the range of the root mean square height of the surface of the oligomer sealing layer formed on the film surface with the root mean square height of 0.03 μm or more. The root mean square heights Rq A and Rq BAt least one of them is preferably 0.12 μm or less, more preferably 0.08 μm or less.

[0054] The root mean square height Rq of the polyester film 11 A and Rq B can be measured by the method described in the following examples.

[0055] In addition, the maximum cross-sectional height Rt of the first film surface 11A A and the maximum cross-sectional height Rt of the second film surface 11B B At least one of them is preferably 0.5 μm or more. The maximum cross-sectional height Rt A and Rt B can be the same value as each other or different values. When the maximum cross-sectional height is 0.5 μm or more, it is easy to control the range of the root mean square height of the surface of the oligomer sealing layer formed on the surface where the maximum cross-sectional height is 0.5 μm or more. The maximum cross-sectional height Rt A and Rt B At least one of them is preferably 1 μm or less, more preferably 0.8 μm or less.

[0056] The maximum cross-sectional height Rt of the polyester film 11 A and Rt B can be measured by the method described in the following examples.

[0057] The thickness of the polyester film 11 is preferably 10 μm or more and 500 μm or less, more preferably 15 μm or more and 300 μm or less, and further preferably 20 μm or more and 250 μm or less.

[0058] (Oligomer Sealing Layer)

[0059] The first oligomer sealing layer 21 and the second oligomer sealing layer 22 are layers for preventing the oligomers in the polyester film from precipitating on the surface of the base material 1 for the adhesive sheet.

[0060] When the base material 1 for the adhesive sheet is exposed to high temperature conditions, the oligomers contained in the polyester film 11 precipitate on the surface of the polyester film 11 due to heating. In the case where the first oligomer sealing layer 21 and the second oligomer sealing layer 22 are not provided, the oligomers precipitate on the first film surface 11A and the second film surface 11B of the polyester film 11.

[0061] The first oligomer sealing layer 21 and the second oligomer sealing layer 22 preferably prevent the oligomers from precipitating on the surface of the base material 1 for the adhesive sheet even under high temperature conditions of 180 °C or more and 200 °C or less (preferably 185 °C or more and 200 °C or less).

[0062] The base material 1 for the adhesive sheet of the present embodiment has a first oligomer sealing layer 21 on the first film surface 11A and a second oligomer sealing layer 22 on the second film surface 11B. Therefore, based on the base material 1 for the adhesive sheet, the precipitation of oligomers on the surface of the base material during heating can be prevented.

[0063] · Root mean square height Rq

[0064] In the base material 1 for the adhesive sheet of the present embodiment, at least one of the root mean square height Rq1 of the surface of the first oligomer sealing layer 21 on the side opposite to the first film surface 11A (sometimes referred to as the first base material surface 21A) and the root mean square height Rq2 of the surface of the second oligomer sealing layer 22 on the side opposite to the second film surface 11B (sometimes referred to as the second base material surface 22A) is 0.031 μm or more. Therefore, one of the root mean square heights Rq1 and Rq2 may be 0.031 μm or more and the other of the root mean square heights Rq1 and Rq2 may be less than 0.031 μm, or both of the root mean square heights Rq1 and Rq2 may be 0.031 μm or more.

[0065] When at least one of the root mean square height Rq1 of the first base material surface 21A of the base material 1 for the adhesive sheet and the root mean square height Rq2 of the second base material surface 22A is 0.031 μm or more, the adhesion between the base materials 1 for the adhesive sheet can be prevented.

[0066] Preferably, at least one of the root mean square heights Rq1 and Rq2 is 0.035 μm or more, and more preferably 0.040 μm or more.

[0067] Preferably, at least one of the root mean square heights Rq1 and Rq2 is 0.1 μm or less, and more preferably 0.06 μm or less.

[0068] The root mean square heights Rq1 and Rq2 may be the same value as each other or may be different values.

[0069] The root mean square heights Rq1 and Rq2 can be adjusted to a desired range, for example, by adjusting the Rq of the first film surface 11A of the polyester film 11 A and the Rq of the second film surface 11B B , adjusting the Rt of the first film surface 11A A and the Rt of the second film surface 11B B , and adjusting the thicknesses of the first oligomer sealing layer 21 and the second oligomer sealing layer 22, etc.

[0070] The root mean square height Rq can be measured by the method described in the examples below.

[0071] · Composition of the oligomer sealing layer

[0072] The materials of the first oligomer sealing layer 21 and the second oligomer sealing layer 22 are not particularly limited as long as they can prevent the oligomers in the polyester film 11 from precipitating on the surface of the base material 1 for the adhesive sheet.

[0073] The first oligomer sealing layer 21 and the second oligomer sealing layer 22 are preferably cured films formed by curing an oligomer sealing layer composition containing a curable component. The oligomer sealing layer composition contains, for example, a thermosetting component. As the thermosetting component, (A) an epoxy compound can be cited. In addition, the oligomer sealing layer composition contains, for example, (B) a polyester compound. In addition, the oligomer sealing layer composition contains, for example, (A) an epoxy compound and (C) a polyfunctional amine compound.

[0074] The first oligomer sealing layer 21 and the second oligomer sealing layer 22 of the present embodiment are preferably cured films formed by curing an oligomer sealing layer composition containing (A) an epoxy compound and (C) a polyfunctional amine compound. The first oligomer sealing layer 21 and the second oligomer sealing layer 22 of the present embodiment are more preferably cured films formed by curing an oligomer sealing layer composition containing (A) an epoxy compound, (B) a polyester compound, and (C) a polyfunctional amine compound.

[0075] In order to promote the curing reaction, the oligomer sealing layer composition used in the formation of the first oligomer sealing layer 21 and the second oligomer sealing layer 22 may further contain (D) an acidic catalyst.

[0076] ·(A) Epoxy compound

[0077] (A) The epoxy compound is preferably a bisphenol A type epoxy compound. As the bisphenol A type epoxy compound, bisphenol A diglycidyl ether etc. can be cited. The weight average molecular weight (Mw) of the bisphenol A type epoxy compound is preferably 1×10 4 or more and 5×10 4 or less. When the weight average molecular weight (Mw) of the bisphenol A type epoxy compound is 1×10 4 or more, the crosslinking density required for the film can be obtained, and it is easy to prevent the precipitation of oligomers. When the weight average molecular weight (Mw) is 5×10 4 or less, the film can be prevented from becoming too hard. The weight average molecular weight Mw is a value converted to standard polystyrene measured by gel permeation chromatography (GPC) method.

[0078] ·(B) Polyester compound

[0079] As the (B) polyester compound, there is no particular limitation, and it can be appropriately selected and used from known polyester compounds. As the polyester compound, specifically, it is a resin obtained by the condensation reaction of a polyol and a polycarboxylic acid, and examples thereof include a non-convertible polyester compound which is a compound modified with a dicarboxylic acid and a diol condensate or a non-drying oil fatty acid, and a convertible polyester compound which is a condensate of a dicarboxylic acid and an alcohol having three or more hydroxyl groups. The polyester compound can be used alone or in combination of two or more.

[0080] As the polyol used as a raw material for the (B) polyester compound, examples thereof include diols, triols, and polyols having four or more hydroxyl groups.

[0081] Examples of the diol include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, trimethylene glycol, tetramethylene glycol, and neopentyl glycol.

[0082] Examples of the triol include glycerin, trimethylolethane, and trimethylolpropane.

[0083] Examples of the polyol having four or more hydroxyl groups include diglycerin, triglycerin, pentaerythritol, dipentaerythritol, mannitol, and sorbitol.

[0084] The polyol can be used alone or in combination of two or more.

[0085] Examples of the polycarboxylic acid include aromatic polycarboxylic acids, aliphatic saturated polycarboxylic acids, aliphatic unsaturated polycarboxylic acids, and polycarboxylic acids based on the Diels-Alder reaction.

[0086] Examples of the aromatic polycarboxylic acid include phthalic anhydride, terephthalic acid, isophthalic acid, and trimellitic anhydride.

[0087] Examples of the aliphatic saturated polycarboxylic acid include succinic acid, adipic acid, and sebacic acid.

[0088] Examples of the aliphatic unsaturated polycarboxylic acid include maleic acid, maleic anhydride, fumaric acid, itaconic acid, and citraconic anhydride.

[0089] Examples of the polycarboxylic acid based on the Diels-Alder reaction include cyclopentadiene-maleic anhydride adduct, terpene-maleic anhydride adduct, and rosin-maleic anhydride adduct.

[0090] The polycarboxylic acid can be used alone or in combination of two or more.

[0091] Examples of the modifier, i.e., non-drying oil fatty acids, etc., include, for example: caprylic acid, lauric acid, palmitic acid, stearic acid, oleic acid, linoleic acid, linolenic acid, eleostearic acid, ricinoleic acid, dehydrated ricinoleic acid, or coconut oil, linseed oil, tung oil, castor oil, dehydrated castor oil, soybean oil, safflower oil, and their fatty acids, etc. These modifiers can be used alone, or two or more of them can be used in combination.

[0092] (B) The polyester compound preferably has an active hydrogen group that serves as a base point for the crosslinking reaction. Examples of the active hydrogen group include, for example: hydroxyl group, carboxyl group, and amino group. The polyester compound particularly preferably has a hydroxyl group. The hydroxyl value of the polyester compound is preferably 5 mgKOH / g or more and 500 mgKOH / g or less, more preferably 10 mgKOH / g or more and 300 mgKOH / g or less.

[0093] (B) The number average molecular weight (Mn) of the polyester compound is preferably 500 or more and 10,000 or less, more preferably 1,000 or more and 8,000 or less. The above-mentioned number average molecular weight is a value converted to standard polystyrene measured by gel permeation chromatography (GPC) method.

[0094] Examples of the (B) polyester compound include: crystalline polyester resin and amorphous polyester resin, and amorphous polyester resin is preferred. The (B) polyester compound is preferably soluble in organic solvents such as toluene.

[0095] (B) The glass transition temperature Tg of the polyester compound is preferably 0°C or more and 50°C or less.

[0096] By using a polyester compound having a number average molecular weight (Mn) and a glass transition temperature Tg within the above ranges, appropriate flexibility can be imparted to the cured film forming the first oligomer sealing layer 21 and the second oligomer sealing layer 22. For the glass transition temperature Tg, in accordance with JIS K 7121:2012, the extrapolated glass transition start temperature was measured in the temperature range of -80°C to 250°C using an input compensation differential scanning calorimeter to obtain the glass transition temperature Tg.

[0097] · (C) Polyfunctional amine compound

[0098] Examples of the (C) polyfunctional amine compound that can be used include, for example: melamine compounds, urea compounds, benzoguanamine compounds, and diamines.

[0099] Examples of the melamine compound include, for example: hexamethoxymethyl melamine, methylated melamine compound, and butylated melamine compound.

[0100] Examples of the urea compound include, for example: methylated urea compound, and butylated urea compound.

[0101] Examples of the benzoguanamine compound include, for example, a methylated benzoguanamine compound and a butylated benzoguanamine compound.

[0102] Examples of the diamine include, for example, ethylenediamine, tetramethylenediamine, hexamethylenediamine, N,N'-diphenylethylenediamine, and p-xylenediamine.

[0103] From the viewpoint of curability, as the (C) polyfunctional amine compound, hexamethoxymethyl melamine is preferred.

[0104] ·(D) Acid catalyst

[0105] Examples of the acid catalyst (D) include, for example, hydrochloric acid and p-toluenesulfonic acid.

[0106] As the curable component contained in the composition for forming the oligomer sealing layer, an energy ray curable component can be used. As the energy ray curable component, a low molecular weight (meth)acrylate compound or a (meth)acrylate oligomer can be used. As the low molecular weight (meth)acrylate compound and the (meth)acrylate oligomer, a polyfunctional compound having a plurality of (meth)acryloyl groups is preferably used, and a polyfunctional compound and a monofunctional compound can be used in combination. When the composition for forming the oligomer sealing layer contains an energy ray curable component, an energy ray polymerization initiator is preferably contained simultaneously.

[0107] It should be noted that the "(meth)acrylate compound" in this specification is a representation method used when indicating both "acrylate compound" and "methacrylate compound", and other similar terms are also treated in the same way.

[0108] ·Filler

[0109] The oligomer sealing layer substantially does not contain a filler. Substantially not containing means that the oligomer sealing layer does not contain a filler except in the case where it is inevitably mixed during the formation of the oligomer sealing layer. Specifically, it means that the content of the filler in the oligomer sealing layer is 0.1% by mass or less. In the present embodiment, the content of the filler in the oligomer sealing layer is preferably 0.01% by mass or less, more preferably 0.001% by mass or less, and further preferably the oligomer sealing layer does not contain a filler.

[0110] As a method for preventing the oligomer sealing layers from sticking to each other, a method of incorporating a filler into the oligomer sealing layer can be considered, but the oligomer sealing layer containing a filler cannot maintain the effect of preventing the oligomer from precipitating in the polyester film. According to the base material for the adhesive sheet of the present embodiment, the oligomer sealing layer substantially does not contain a filler, and not only can maintain the oligomer sealing performance, but also has anti-sticking properties.

[0111] As the filling material, for example, fillers can be cited. As fillers, for example, inorganic fillers and organic fillers can be listed.

[0112] As the inorganic fillers, silica fillers, alumina fillers, boron nitride fillers, etc. can be listed. As the silica fillers, for example, fused silica, spherical silica, etc. can be listed.

[0113] In addition, as the organic filler, synthetic resin powder can be cited. As the synthetic resin powder, for example, powders of various thermosetting resins or thermoplastic resins such as alkyd resin, epoxy resin, silicone resin, phenolic resin, polyester, acrylic resin, acetal resin, polyethylene, polyether, polycarbonate, polyamide, polysulfone, polystyrene, polyvinyl chloride, fluororesin, polypropylene, ethylene-vinyl acetate copolymer, etc., or powders of copolymers of these resins can be listed. In addition, as other examples of the organic filler, aromatic or aliphatic polyamide fibers, polypropylene fibers, polyester fibers, aramid fibers, etc. can be listed.

[0114] ·Cured film

[0115] The first oligomer sealing layer 21 and the second oligomer sealing layer 22 are each independently preferably a cured film formed by curing an oligomer sealing layer composition, and the oligomer sealing layer composition contains (A) bisphenol A type epoxy compound, (B) polyester compound, and (C) polyfunctional amine compound at a compounding ratio of (A) 50% by mass or more and 85% by mass or less, (B) 5% by mass or more and 30% by mass or less, and (C) 5% by mass or more and 30% by mass or less, respectively. When (D) an acidic catalyst is compounded in the oligomer sealing layer composition, the content of the (D) component is preferably 1% by mass or more and 5% by mass or less.

[0116] According to the cured film formed by curing the oligomer sealing layer composition having the compounding ratio within the above range, the effect of preventing the precipitation of the oligomer on the surface of the base material 1 for the adhesive sheet can be easily improved.

[0117] As a more specific example of the oligomer sealing layer composition of the present embodiment, for example, the following examples of the oligomer sealing layer composition can be cited, but the present invention is not limited to such examples. In addition, the composition used for forming the first oligomer sealing layer 21 and the composition used for forming the second oligomer sealing layer 22 may have the same composition or different compositions from each other.

[0118] As an example of the composition for the oligomer sealing layer of the present embodiment, the following composition for the oligomer sealing layer can be cited. It contains (A) an epoxy compound, (B) a polyester compound, (C) a polyfunctional amine compound, and (D) an acidic catalyst. The (A) epoxy compound is a bisphenol A type epoxy compound, and the (C) polyfunctional amine compound is a melamine compound.

[0119] As an example of the composition for the oligomer sealing layer of the present embodiment, the following composition for the oligomer sealing layer can be cited. It contains (A) an epoxy compound, (B) a polyester compound, (C) a polyfunctional amine compound, and (D) an acidic catalyst. The (A) epoxy compound is a bisphenol A type epoxy compound, and the weight average molecular weight (Mw) of the (A) epoxy compound is 1×10 4 or more and 5×10 4 or less, and the (C) polyfunctional amine compound is a melamine compound.

[0120] As an example of the composition for the oligomer sealing layer of the present embodiment, the following composition for the oligomer sealing layer can be cited. It contains (A) an epoxy compound, (B) a polyester compound, (C) a polyfunctional amine compound, and (D) an acidic catalyst. The (A) epoxy compound is a bisphenol A type epoxy compound, the number average molecular weight (Mn) of the (B) polyester compound is 500 or more and 10,000 or less, the glass transition temperature Tg of the (B) polyester compound is 0°C or more and 50°C or less, and the (C) polyfunctional amine compound is a melamine compound.

[0121] As an example of the composition for the oligomer sealing layer of the present embodiment, the following composition for the oligomer sealing layer can be cited. It contains (A) an epoxy compound, (B) a polyester compound, (C) a polyfunctional amine compound, and (D) an acidic catalyst. The (A) epoxy compound is a bisphenol A type epoxy compound, the weight average molecular weight (Mw) of the (A) epoxy compound is 1×10 4 or more and 5×10 4 or less, the number average molecular weight (Mn) of the (B) polyester compound is 500 or more and 10,000 or less, the glass transition temperature Tg of the (B) polyester compound is 0°C or more and 50°C or less, and the (C) polyfunctional amine compound is a melamine compound.

[0122] · Film thickness of the oligomer sealing layer

[0123] The thickness of the first oligomer sealing layer 21 and the thickness of the second oligomer sealing layer 22 are each independently preferably 50 nm or more and 500 nm or less, more preferably 80 nm or more and 300 nm or less, and further preferably 50 nm or more and 180 nm or less.

[0124] When the thickness of the first oligomer sealing layer 21 and the thickness of the second oligomer sealing layer 22 are 50 nm or more, the precipitation of the oligomers contained in the polyester film 11 on the surface of the base material 1 for adhesive sheet can be effectively prevented.

[0125] When the thickness of the first oligomer sealing layer 21 and the thickness of the second oligomer sealing layer 22 are 500 nm or less, it is easy to make the root mean square height of the first base material surface 21A of the first oligomer sealing layer 21 and the second base material surface 22A of the second oligomer sealing layer 22 be 0.031 μm or more.

[0126] It should be noted that, the greater the thickness of the first oligomer sealing layer 21 and the thickness of the second oligomer sealing layer 22 increase, the better the oligomer sealing effect. From the viewpoint of adjusting the root mean square height Rq1 of the first base material surface 21A of the first oligomer sealing layer 21 and the root mean square height Rq2 of the second base material surface 22A of the second oligomer sealing layer 22, the thickness of the first oligomer sealing layer 21 and the thickness of the second oligomer sealing layer 22 can be 100 nm or more and 200 nm or less, or can be about 150 nm. In addition, it is preferable to set at least one of the thickness of the first oligomer sealing layer 21 and the thickness of the second oligomer sealing layer 22 in the range of 80 nm or more and 180 nm or less. In addition, in the first oligomer sealing layer 21 and the second oligomer sealing layer 22, the thickness of the oligomer sealing layer having a base material surface with a root mean square height of 0.031 μm or more is also preferably 80 nm or more and 180 nm or less. For example, it is preferable that both the root mean square height Rq1 of the first base material surface 21A and the root mean square height Rq2 of the second base material surface 22A are independently 0.031 μm or more, and the thicknesses of the first oligomer sealing layer 21 and the second oligomer sealing layer 22 are independently 80 nm or more and 180 nm or less. In addition, for example, it is preferable that the root mean square height Rq2 of the second base material surface 22A is 0.031 μm or more, and the thickness of the second oligomer sealing layer 22 is 80 nm or more and 180 nm or less.

[0127] (Method for manufacturing the base material for adhesive sheet)

[0128] The base material 1 for adhesive sheet of the present embodiment can be manufactured, for example, through the following steps.

[0129] First, a composition for forming an oligomer sealing layer containing a thermosetting component is coated on the first film surface 11A of the polyester film 11 to form a first coating film. Next, the first coating film is heated and cured to form a first cured film as the first oligomer sealing layer 21. The temperature as the heating and curing condition is, for example, 120 °C or more and 170 °C or less. The heating time as the heating and curing condition is 5 seconds or more and 5 minutes or less.

[0130] Next, a composition for forming an oligomer sealing layer is coated on the second film surface 11B of the polyester film 11 to form a second coating film. Then, the second coating film is heated and cured to form a second cured film as the second oligomer sealing layer 22. The temperature and heating time as the heat curing conditions are, for example, in the same range as those of the first cured film.

[0131] It should be noted that the manufacturing method of the base material 1 for the adhesive sheet is not limited to this method. For example, the base material 1 for the adhesive sheet can also be manufactured by a manufacturing method in which a second cured film as the second oligomer sealing layer 22 is formed on the second film surface 11B of the polyester film 11, and then a first cured film as the first oligomer sealing layer 21 is formed on the first film surface 11A.

[0132] As the curable component contained in the composition for forming the oligomer sealing layer, in the case of using an energy ray curable component, a step of irradiating the first coating film or the second coating film with energy rays such as ultraviolet rays for curing can be performed instead of the heat curing step of forming the first cured film or the second cured film.

[0133] When coating the composition for the oligomer sealing layer to form the first oligomer sealing layer 21 and the second oligomer sealing layer 22, it is preferable to dilute the composition for the oligomer sealing layer with an organic solvent to prepare a coating solution and use it.

[0134] The organic solvent used for preparing the coating solution is not particularly limited. Examples of the organic solvent include: aromatic solvents, aliphatic solvents, ester solvents, ketone solvents, and alcohol solvents. Examples of the aromatic solvent include: benzene, toluene, and xylene. Examples of the aliphatic solvent include: n-hexane and n-heptane. Examples of the ester solvent include: ethyl acetate and butyl acetate. Examples of the ketone solvent include: methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, and cyclopentanone. Examples of the alcohol solvent include: isopropyl alcohol and methanol.

[0135] Examples of the method of coating the coating solution include: spin coating method, spraying method, bar coating method, knife coating method, roll knife coating method, roll coating method, blade coating method, die coating method, and gravure coating method, etc.

[0136] In order to prevent the organic solvent and low-boiling components from remaining in the first oligomer sealing layer 21 and the second oligomer sealing layer 22, it is preferable to heat and dry the coating film after coating the coating solution on the polyester film 11.

[0137] (Use of the base material for the adhesive sheet)

[0138] Preferably, the base material 1 for the adhesive sheet of the present embodiment is used as the base material of an adhesive sheet, and the adhesive sheet is an adhesive sheet for processing electronic components.

[0139] (Effect of the Embodiment)

[0140] According to the base material 1 for the adhesive sheet, both surfaces of the polyester film 11 are covered with the first oligomer sealing layer 21 and the second oligomer sealing layer 22. Therefore, even after the step of applying high-temperature conditions, the oligomers in the polyester film 11 can be prevented from precipitating on the surface of the base material 1 for the adhesive sheet. Thus, the members or devices in contact with the base material 1 for the adhesive sheet can be prevented from being contaminated by the oligomers in the polyester film 11. In addition, when the base material 1 for the adhesive sheet is used as the base material of the adhesive sheet, the surface of the adherend to which the adhesive sheet is pasted can be prevented from being contaminated.

[0141] In addition, since the polyester film 11 is an annealed film, even when high-temperature conditions are applied, the thermal shrinkage of the base material 1 for the adhesive sheet can be reduced. Therefore, when the base material 1 for the adhesive sheet is used as the base material of the adhesive sheet, adverse effects such as warping of the adherend to which the adhesive sheet is pasted due to the thermal shrinkage of the adhesive sheet can be reduced.

[0142] In addition, since at least one of the root mean square heights Rq1 of the first base material surface 21A and Rq2 of the second base material surface 22A of the base material 1 for the adhesive sheet is 0.031 μm or more, the adhesion of the base material 1 for the adhesive sheet can be prevented.

[0143] Therefore, the base material 1 for the adhesive sheet according to the present embodiment has excellent heat resistance, and even after the step of applying high-temperature conditions, the contamination of the surface of the members or devices and the surface of the adherend can be prevented, the influence caused by the deformation of the adhesive sheet due to high-temperature conditions can be reduced, and the adhesion can also be prevented.

[0144] 〔Second Embodiment〕

[0145] The adhesive sheet of the second embodiment is an adhesive sheet using the base material for the adhesive sheet described in the first embodiment. In the second embodiment, the description of the same matters as those in the first embodiment is omitted or simplified. In addition, the description of symbols is sometimes omitted.

[0146] (Adhesive Sheet)

[0147] Figure 2 A cross-sectional schematic view of the adhesive sheet 2 of the present embodiment is shown.

[0148] The adhesive sheet 2 has a base material 1 for the adhesive sheet, an adhesive layer 30, and a release sheet RL. The base material 1 for the adhesive sheet can be the base material for the adhesive sheet described in the first embodiment.

[0149] In the adhesive sheet 2, the adhesive layer 30 is laminated on the surface (the first base material surface 21A) of the first oligomer sealing layer 21 on the side opposite to the surface facing the first film surface 11A. Further, a release sheet RL is laminated on the adhesive layer 30. When using the adhesive sheet 2, the release sheet RL is peeled off from the adhesive layer 30.

[0150] Further, in the adhesive sheet 2, no adhesive layer is laminated on the surface (the second base material surface 22A) of the second oligomer sealing layer 22 on the side opposite to the surface facing the second film surface 11B, and the adhesive sheet 2 is a single-sided adhesive sheet. The adhesive sheet is not limited to Figure 2 the structure shown. For example, it may also be a single-sided adhesive sheet in which the adhesive layer is laminated on the second base material surface 22A and not laminated on the first base material surface 21A.

[0151] The shape of the adhesive sheet 2 can be any shape such as a sheet shape, a strip shape, a label shape, etc.

[0152] (Polyester film)

[0153] The polyester film 11 in the adhesive sheet 2 is the same as that in the first embodiment.

[0154] (Oligomer sealing layer)

[0155] The first oligomer sealing layer 21 and the second oligomer sealing layer 22 in the adhesive sheet 2 are the same as those in the first embodiment. The first oligomer sealing layer 21 provided between the adhesive layer 30 and the polyester film 11 can also prevent oligomers from penetrating into the adhesive layer 30 under high-temperature conditions, and thus can prevent contamination of the adherend to which the adhesive sheet 2 is adhered. It is preferred that the first oligomer sealing layer 21 also prevents oligomers from penetrating into the adhesive layer 30 under high-temperature conditions of 180 °C or higher and 200 °C or lower (preferably 185 °C or higher and 200 °C or lower).

[0156] (Adhesive layer)

[0157] The adhesive layer 30 of the present embodiment contains an adhesive composition. As the adhesive contained in the adhesive composition, there is no particular limitation, and various adhesives can be applied to the adhesive layer 30. Examples of the adhesive contained in the adhesive layer 30 include: rubber-based, acrylic, silicone, polyester, and urethane. It should be noted that the type of adhesive can be selected in consideration of the use and the type of the adherend to be adhered, etc. The adhesive layer 30 preferably contains an acrylic adhesive composition or a silicone adhesive composition, and more preferably contains an acrylic adhesive composition.

[0158] The acrylic adhesive composition contains an acrylic polymer. The acrylic polymer can be a homopolymer or a copolymer. From the viewpoint that the adhesive layer 30 can be easily peeled from the adherend even after a process of applying high-temperature conditions, the acrylic adhesive composition preferably contains an acrylic polymer having a main component of an alkyl (meth)acrylate having 6 to 10 carbon atoms as a monomer, and more preferably contains an acrylic polymer having a main component of an alkyl (meth)acrylate having 8 carbon atoms as a monomer. Examples of the alkyl (meth)acrylate having 8 carbon atoms include n-octyl (meth)acrylate, isooctyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate, among which 2-ethylhexyl (meth)acrylate is preferred.

[0159] In this specification, an acrylic polymer having a main component of an alkyl (meth)acrylate having 6 to 10 carbon atoms or an alkyl (meth)acrylate having 8 carbon atoms as a monomer means that the mass ratio of the alkyl (meth)acrylate having 6 to 10 carbon atoms or the alkyl (meth)acrylate having 8 carbon atoms to the mass of the monomers used for synthesizing the acrylic polymer is 50% by mass or more. The mass ratio of the alkyl (meth)acrylate having 6 to 10 carbon atoms or the alkyl (meth)acrylate having 8 carbon atoms to the mass of the monomers used for synthesizing the acrylic polymer is preferably 60% by mass or more, and more preferably 70% by mass or more.

[0160] From the viewpoints of increasing the adhesive force of the adhesive sheet 2 and improving the cohesiveness of the adhesive layer 30 after a process of applying high-temperature conditions, the acrylic polymer preferably contains a structural unit derived from a monomer having a nitrogen-containing functional group. Herein, the above nitrogen-containing functional group does not include an N-H bond.

[0161] For the adhesive sheet 2, since the substrate 1 for the adhesive sheet has an oligomer sealing layer, it is possible to prevent contamination of the surface of the adherend even after a process of applying high-temperature conditions. Since the acrylic polymer contains a structural unit derived from a monomer having a nitrogen-containing functional group, the cohesiveness of the adhesive layer 30 after a process of applying high-temperature conditions is improved, and the effect of preventing contamination of the surface of the adherend can be further enhanced.

[0162] The ethylenically unsaturated monomer having a nitrogen-containing functional group is preferably at least one selected from heterocyclic vinyl compounds, (meth)acrylamide compounds, amino (meth)acrylate compounds, and (meth)acrylonitrile, and more preferably a heterocyclic vinyl compound. Herein, these compounds do not include an N-H bond.

[0163] It can be considered that the heterocyclic group contained in the heterocyclic vinyl compound is not easily decomposed even when the adhesive sheet is heated due to its structure (ring structure). Therefore, it can be considered that when the monomer having a nitrogen-containing functional group is a heterocyclic vinyl compound, it is easier to maintain the cohesion of the adhesive layer, and the effects of the present embodiment can be further exhibited.

[0164] The monomer having a nitrogen-containing functional group can be used alone or in combination of two or more.

[0165] Examples of the heterocyclic vinyl compound include: N-acryloylmorpholine, N-methacryloylmorpholine, N-vinyl-2-pyrrolidone, N-acryloylpyrrolidone, N-methacryloylpyrrolidone, N-acryloylpiperidine, N-methacryloylpiperidine, N-acryloylpyrrole, N-methacryloylpyrrole, N-acryloylaziridine, N-methacryloylaziridine, aziridinylethyl acrylate, aziridinylethyl methacrylate, 2-vinylpyridine, 4-vinylpyridine, 2-vinylpyrazine, 1-vinylimidazole, N-vinylcarbazole, and N-vinylphthalimide, etc.

[0166] Among them, as the heterocyclic vinyl compound, from the viewpoint of exhibiting the effects of the present embodiment, N-acryloylmorpholine, N-vinyl-2-pyrrolidone, N-acryloylpyrrolidone, N-acryloylpiperidine, N-acryloylpyrrole, N-acryloylaziridine, aziridinylethyl acrylate, 2-vinylpyridine, 4-vinylpyridine, 2-vinylpyrazine, 1-vinylimidazole, N-vinylcarbazole, or N-vinylphthalimide is preferred, and N-acryloylmorpholine is more preferred.

[0167] Examples of the (meth)acrylamide compound include: N,N-dimethylacrylamide, N,N-dimethylmethacrylamide, N,N-diethylacrylamide, N,N-diethylmethacrylamide, N,N-dipropylacrylamide, N,N-dipropylmethacrylamide, N,N-diisopropylacrylamide, N,N-diisopropylmethacrylamide, N,N-diallylacrylamide, N,N-diallylmethacrylamide, N,N-dibutylacrylamide, N,N-dibutylmethacrylamide, N,N-ethylmethylacrylamide, and N,N-ethylmethylmethacrylamide, etc.

[0168] Among them, as the (meth)acrylamide compound, from the viewpoint of exhibiting the effects of the present embodiment, N,N-dimethylacrylamide, N,N-diethylacrylamide, N,N-di-n-propylacrylamide, N,N-diisopropylacrylamide, N,N-diallylacrylamide, N,N-di-n-butylacrylamide, or N,N-ethylmethylacrylamide is preferable, and N,N-dimethylacrylamide is more preferable.

[0169] The proportion of the structural unit derived from the monomer having a nitrogen-containing functional group in the total mass of the acrylic polymer is preferably 1% by mass or more and 20% by mass or less, more preferably 4.5% by mass or more and 18% by mass or less, and further preferably 9% by mass or more and 15% by mass or less. When the proportion of the structural unit derived from the monomer having a nitrogen-containing functional group is in such a range, it becomes easier to adjust the adhesive strength of the adhesive sheet 2 and the cohesiveness of the adhesive layer 30 after the step of applying high-temperature conditions.

[0170] The adhesive layer 30 containing the acrylic adhesive composition may contain a compound obtained by crosslinking an acrylic polymer with a crosslinking agent. As the crosslinking agent, for example, at least one crosslinking agent selected from isocyanate-based crosslinking agents and epoxy-based crosslinking agents can be cited.

[0171] In addition, the adhesive layer 30 may contain a polymer of a polyvalent compound having an energy-ray polymerizable functional group. As the polyvalent compound having an energy-ray polymerizable functional group, for example, low-molecular-weight (meth)acrylate compounds and (meth)acrylate oligomers can be cited. By irradiating the acrylic adhesive composition containing the polyvalent compound having an energy-ray polymerizable functional group with energy rays, the polyvalent compounds having an energy-ray polymerizable functional group polymerize with each other to form a crosslinked structure, and the cohesiveness of the adhesive layer 30 after the step of applying high-temperature conditions is further improved.

[0172] In addition, from the viewpoint that the adhesive layer 30 can be easily peeled from the adherend even after the step of applying high-temperature conditions, the adhesive layer 30 can have a function of reducing adhesiveness by containing a compound having an unreacted energy-ray polymerizable functional group when using the adhesive sheet 2 and irradiating energy rays after pasting the adhesive sheet 2 on the adherend. In this case, the acrylic polymer only needs to be a compound having an unreacted energy-ray polymerizable functional group. For example, the acrylic polymer may have an unreacted energy-ray polymerizable functional group such as (meth)acryloyl in the side chain.

[0173] The thickness of the adhesive layer 30 can be appropriately determined according to the use of the adhesive sheet 2. In the present embodiment, the thickness of the adhesive layer 30 is preferably 5 μm or more and 60 μm or less, and more preferably 10 μm or more and 50 μm or less.

[0174] In this embodiment, within the scope that does not impair the effects of the present invention, the adhesive composition may contain other components. Examples of other components that can be contained in the adhesive composition include, for example: flame retardants, tackifiers, ultraviolet absorbers, light stabilizers, antioxidants, antistatic agents, preservatives, mildew-proof agents, plasticizers, defoaming agents, colorants, fillers, and wettability modifiers, etc.

[0175] (Release sheet)

[0176] The release sheet RL is not particularly limited. For example, from the viewpoint of ease of operation, the release sheet RL preferably includes a release substrate and a release agent layer formed by coating a release agent on the release substrate. In addition, the release sheet may have a release agent layer on only one side of the release substrate, or may have release agent layers on both sides of the release substrate.

[0177] Examples of the release substrate include, for example: paper substrates, laminated papers formed by laminating a thermoplastic resin such as polyethylene on the paper substrate, and plastic films, etc. Examples of the paper substrate include: cellophane, coated paper, and cast-coated paper, etc. Examples of the plastic film include: polyester films (for example, polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, etc.), and polyolefin films (for example, polypropylene, and polyethylene, etc.), etc.

[0178] Examples of the release agent include, for example: olefin resins, rubber-like elastomers (for example, butadiene resins, and isoprene resins, etc.), long-chain alkyl resins, alkyd resins, fluororesins, and silicone resins, etc. When the adhesive layer is formed of a silicone-based adhesive composition, the release agent is preferably a non-silicone-based release agent.

[0179] The thickness of the release sheet RL is not particularly limited. The thickness of the release sheet RL is generally 20 μm or more and 200 μm or less, preferably 25 μm or more and 150 μm or less.

[0180] The thickness of the release agent layer is not particularly limited. When forming the release agent layer by coating a solution containing a release agent, the thickness of the release agent layer is preferably 0.01 μm or more and 2.0 μm or less, more preferably 0.03 μm or more and 1.0 μm or less.

[0181] When using a plastic film as the release substrate, the thickness of the plastic film is preferably 3 μm or more and 50 μm or less, more preferably 5 μm or more and 40 μm or less.

[0182] (Manufacturing method of the adhesive sheet)

[0183] The manufacturing method of the adhesive sheet 2 is not particularly limited.

[0184] For example, the adhesive sheet 2 can be manufactured through the following steps.

[0185] First, an adhesive layer 30 is formed on the base material 1 for the adhesive sheet. Specifically, an adhesive composition is spread or coated on the first base material surface 21A of the first oligomer sealing layer 21 to form a sheet-like adhesive composition (adhesive layer 30). When using the coating liquid for forming the adhesive layer described later, the adhesive layer 30 can be formed by drying the obtained coating film, and thus the adhesive sheet 2 can be manufactured. A release sheet RL can be laminated on the formed adhesive layer 30 as needed.

[0186] In addition, the adhesive sheet 2 having the release sheet RL can be manufactured, for example, through the following steps. First, an adhesive composition is spread or coated on the release sheet RL to form a sheet-like adhesive composition (adhesive layer 30). When using the coating liquid for forming the adhesive layer described later, the obtained coating film is dried to form the adhesive layer 30. The adhesive sheet 2 can be manufactured by laminating the adhesive layer 30 on the release sheet RL with the first oligomer sealing layer 21 of the base material 1 for the adhesive sheet.

[0187] When forming the adhesive layer 30 by coating the adhesive composition, it is preferable to prepare a coating liquid by diluting the adhesive composition with an organic solvent and then use it.

[0188] The organic solvent used for preparing the coating liquid for forming the adhesive layer is not particularly limited. As the organic solvent used in the adhesive composition, the organic solvent used for preparing the coating liquid of the composition for the oligomer sealing layer can be cited.

[0189] As the coating method of the coating liquid for forming the adhesive layer, the same method as the method for coating the coating liquid of the composition for the oligomer sealing layer can be cited.

[0190] In order to prevent the organic solvent and low-boiling components from remaining in the adhesive layer 30, as described above, it is preferable to heat and dry the coating film after coating the coating liquid on the base material 1 for the adhesive sheet.

[0191] When a crosslinking agent is incorporated into the adhesive composition, in order to carry out the crosslinking reaction and improve the cohesion, it is preferable to heat the coating film.

[0192] (Use of the adhesive sheet)

[0193] The adhesive sheet can be used as an adhesive sheet for processing electronic components. In addition, as other usage modes of the adhesive sheet, there can be mentioned the usage mode for fixing or protecting electronic components. As an example of fixing or protecting electronic components, an adhesive sheet is used when sealing a semiconductor element. In the case where the adhesive layer 30 contains a polymer of a polyvalent compound having an energy ray-polymerizable functional group, the adhesive sheet of the present embodiment can be used after a curable product is formed by polymerizing and curing the polyvalent compound having an energy ray-polymerizable functional group in the adhesive composition.

[0194] When sealing a semiconductor element in a state where it is not placed on a metal lead frame but is pasted on the adhesive sheet, it is preferable to use the adhesive sheet. Specifically, it is preferable that the adhesive sheet is not used when sealing a semiconductor element placed on a metal lead frame, but is used when sealing a semiconductor element in a state where it is pasted on the adhesive layer. That is, it is preferable to use it in a state where the semiconductor element is directly pasted on the adhesive sheet. In the case where the cohesiveness of the adhesive layer 30 of the adhesive sheet of the present embodiment is excellent, in the semiconductor element sealing process, from the viewpoint of preventing the semiconductor element from being displaced, it is preferable to use it in such a process. As a form of packaging a semiconductor element without using a metal lead frame, there can be mentioned panel level package (PLP) and WLP (wafer level package), etc.

[0195] The adhesive sheet is also preferably used in a process having the following steps: a step of pasting a frame member having a plurality of openings on the adhesive sheet, a step of pasting a semiconductor chip on the adhesive layer exposed in the openings of the frame member, a step of coating the semiconductor chip with a sealing resin, and a step of thermally curing the sealing resin.

[0196] After the step of thermally curing the sealing resin, as a step performed in a high-temperature environment or a high-temperature and reduced-pressure environment, a processing step such as plasma treatment is sometimes performed.

[0197] As steps other than the step of thermally curing the sealing resin and the plasma treatment step and performed in a high-temperature environment or a high-temperature and reduced-pressure environment, there can be listed, for example: a step of sputtering a metal or the like on an electronic component, a step of cleaning an electronic component with hot water or the like, and a baking treatment step in lithography, etc.

[0198] (Effect of the embodiment)

[0199] According to the adhesive sheet 2 of the present embodiment, the following effects are exhibited.

[0200] It can be considered that when the adhesive sheet 2 is exposed to high-temperature conditions, the oligomers contained in the polyester film 11 precipitate on the surface of the polyester film 11 due to heating. In the case where the first oligomer sealing layer 21 is not provided, they penetrate into the adhesive layer 30 and further reach the surface of the adhesive layer 30 through the adhesive layer 30. The adhesive sheet 2 has a first oligomer sealing layer 21 between the polyester film 11 and the adhesive layer 30. Therefore, even when the adhesive sheet 2 is used in a process under high-temperature environment or high-temperature and reduced-pressure environment, according to the adhesive sheet 2, the oligomers in the polyester film 11 can be prevented from penetrating into the adhesive layer 30. Therefore, contamination of the surface of the adherend to which the adhesive sheet 2 is adhered can be prevented. In addition, for the side of the second oligomer sealing layer 22 of the adhesive sheet 2, although the second base material surface 22A is exposed, through the second oligomer sealing layer 22, the oligomers in the polyester film 11 can be prevented from precipitating on the second base material surface 22A. Therefore, according to the adhesive sheet 2, contamination of the members or devices used in the process using the adhesive sheet 2 can be prevented.

[0201] In addition, since the polyester film 11 is an annealed film, even when high-temperature conditions are applied, the thermal shrinkage of the adhesive sheet 2 can be reduced. Therefore, adverse effects such as warping of the adherend caused by the thermal shrinkage of the adhesive sheet 2 can be reduced.

[0202] In addition, at least one of the root mean square height Rq1 of the first base material surface 21A and the root mean square height Rq2 of the second base material surface 22A of the base material for adhesive sheet 1 is 0.031 μm or more. Therefore, even when the base material surfaces before laminating the adhesive layer 30 come into contact with each other, adhesion can be prevented.

[0203] Therefore, according to the adhesive sheet 2 for electronic component processing of the present embodiment, it has excellent heat resistance, can prevent contamination of the surfaces of the adherend and the members or devices after passing through the process of applying high-temperature conditions, can reduce the influence caused by the deformation of the adhesive sheet due to high-temperature conditions, and can also prevent adhesion.

[0204] 〔Third Embodiment〕

[0205] The adhesive sheet of the third embodiment is different from the adhesive sheet described in the second embodiment in that adhesive layers are provided on both sides of the base material for adhesive sheet. Other aspects of the third embodiment are the same as those of the second embodiment, so the description thereof is omitted or simplified. In addition, the description of symbols is sometimes omitted.

[0206] (Adhesive Sheet)

[0207] Figure 3 is a schematic cross-sectional view of the adhesive sheet 3 of the present embodiment.

[0208] The adhesive sheet 3 has a base material 1 for the adhesive sheet, a first adhesive layer 31, a second adhesive layer 32, a first release sheet RL1, and a second release sheet RL2. The base material 1 for the adhesive sheet can be the base material for the adhesive sheet described in the first embodiment.

[0209] In the adhesive sheet 3, the first adhesive layer 31 is laminated on the surface (the first base material surface 21A) of the first oligomer sealing layer 21 opposite to the surface facing the first film surface 11A. Further, the first release sheet RL1 is laminated on the first adhesive layer 31. When using the adhesive sheet 3, the first release sheet RL1 is peeled off from the first adhesive layer 31.

[0210] In addition, in the adhesive sheet 3, the second adhesive layer 32 is laminated on the surface (the second base material surface 22A) of the second oligomer sealing layer 22 opposite to the surface facing the second film surface 11B. Further, the second release sheet RL2 is laminated on the second adhesive layer 32. When using the adhesive sheet 3, the second release sheet RL2 is peeled off from the second adhesive layer 32.

[0211] The adhesive sheet 3 is a double-sided adhesive sheet having adhesive layers on both sides of the base material 1 for the adhesive sheet. Therefore, a first adherend can be adhered to the first adhesive layer 31 of the adhesive sheet 3, and a second adherend can be adhered to the second adhesive layer 32.

[0212] The shape of the adhesive sheet 3 can be any shape such as a sheet shape, a strip shape, a label shape, etc.

[0213] (Polyester film)

[0214] The polyester film 11 in the adhesive sheet 3 is the same as that in the first embodiment.

[0215] (Oligomer sealing layer)

[0216] The first oligomer sealing layer 21 and the second oligomer sealing layer 22 in the adhesive sheet 3 are the same as those in the first embodiment. The first oligomer sealing layer 21 provided between the first adhesive layer 31 and the polyester film 11 and the second oligomer sealing layer 22 provided between the second adhesive layer 32 and the polyester film 11 can also prevent oligomers from infiltrating into the first adhesive layer 31 and the second adhesive layer 32 under high-temperature conditions, and thus can prevent contamination of the adherends to which the adhesive sheet 3 is adhered. It is preferable that the first oligomer sealing layer 21 and the second oligomer sealing layer also prevent oligomers from infiltrating into the first adhesive layer 31 and the second adhesive layer 32 under high-temperature conditions of 180°C or higher and 200°C or lower (preferably 185°C or higher and 200°C or lower).

[0217] (Adhesive layer)

[0218] The first adhesive layer 31 and the second adhesive layer 32 of this embodiment are the same as the adhesive layer 30 of the above embodiment. The compositions of the adhesive compositions contained in the first adhesive layer 31 and the second adhesive layer 32 may be the same as or different from each other. The thicknesses of the first adhesive layer 31 and the second adhesive layer 32 may be the same as or different from each other.

[0219] (Method for manufacturing an adhesive sheet)

[0220] The method for manufacturing the adhesive sheet 3 is not particularly limited.

[0221] For example, the adhesive sheet 3 can be manufactured through the following steps.

[0222] First, the first adhesive layer 31 is formed on the base material 1 for the adhesive sheet. Specifically, a coating liquid for forming an adhesive layer obtained by diluting the adhesive composition with an organic solvent is coated on the first base material surface 21A of the first oligomer sealing layer 21 to form a coating film. Then, the coating film is dried to form the first adhesive layer 31. If necessary, the first release sheet RL1 is laminated on the formed first adhesive layer 31. Next, a coating liquid for forming an adhesive layer is coated on the second base material surface 22A of the second oligomer sealing layer 22 to form a coating film. Then, the coating film is dried to form the second adhesive layer 32. If necessary, the second release sheet RL2 is laminated on the formed second adhesive layer 32. Through such a method, the adhesive sheet 3 can also be manufactured.

[0223] In addition, the adhesive sheet 3 having the first release sheet RL1 and the second release sheet RL2 can be manufactured, for example, through the following steps. First, a coating liquid for forming an adhesive layer is coated on the first release sheet RL1 to form a coating film. Then, the coating film is dried to form the first adhesive layer 31. The first adhesive layer 31 on the first release sheet RL1 is laminated on the first oligomer sealing layer 21 of the base material 1 for the adhesive sheet. Next, a coating liquid for forming an adhesive layer is coated on the second release sheet RL2 to form a coating film. Then, the coating film is dried to form the second adhesive layer 32. By laminating the second adhesive layer 32 on the second release sheet RL2 with the second oligomer sealing layer 22 of the base material 1 for the adhesive sheet, the adhesive sheet 3 can be manufactured.

[0224] As described above, when coating the adhesive composition to form the first adhesive layer 31 and the second adhesive layer 32, it is preferable to prepare the coating liquid in the same manner as the adhesive layer 30 and use it.

[0225] (Effects of the embodiment)

[0226] According to the adhesive sheet 3 of this embodiment, the following effects are exhibited.

[0227] When the adhesive sheet 3 is exposed to high-temperature conditions, the oligomers contained in the polyester film 11 precipitate on the surface of the polyester film 11 due to heating. In the case where the first oligomer sealing layer 21 and the second oligomer sealing layer 22 are not provided, they penetrate into the first adhesive layer 31 and the second adhesive layer 32. Further, it is considered that the oligomers reach the surfaces of the first adhesive layer 31 and the second adhesive layer 32 through the first adhesive layer 31 and the second adhesive layer 32.

[0228] The adhesive sheet 3 has a first oligomer sealing layer 21 between the polyester film 11 and the first adhesive layer 31, and a second oligomer sealing layer 22 between the polyester film 11 and the second adhesive layer 32. Therefore, even when the adhesive sheet 3 is heated, it is possible to prevent the oligomers in the polyester film 11 from moving to the interfaces between the first adhesive layer 31 and the first adherend and between the second adhesive layer 32 and the second adherend, thereby contaminating the first adherend and the second adherend.

[0229] In addition, since the polyester film 11 is an annealed film, even when high-temperature conditions are applied, the thermal shrinkage of the adhesive sheet 3 can be reduced. Therefore, adverse effects such as warping of the adherend due to the thermal shrinkage of the adhesive sheet 3 can be reduced.

[0230] In addition, since at least one of the root mean square heights Rq1 of the first base material surface 21A and Rq2 of the second base material surface 22A of the adhesive sheet base material 1 is 0.031 μm or more, adhesion of the adhesive sheet base material 1 can be prevented during the manufacture of the adhesive sheet 3.

[0231] Therefore, the adhesive sheet 3 for electronic component processing according to the present embodiment has excellent heat resistance, can prevent contamination of the surface of the adherend even after a process of applying high-temperature conditions, can reduce the influence caused by deformation of the adhesive sheet due to high-temperature conditions, and can also prevent adhesion.

[0232] 〔Modifications of the Embodiment〕

[0233] The present invention is not limited to the above-described embodiment, and modifications and improvements within the scope capable of achieving the object of the present invention are included in the present invention. It should be noted that in the following description, if the components are the same as those described in the above embodiment, the same reference numerals are given and the description thereof is omitted or simplified.

[0234] The adhesive sheet base material and the adhesive sheet may be sheets.

[0235] The sheet-shaped adhesive sheet base material may be provided in a state where multiple sheets are stacked. Since at least one of the root mean square heights Rq of the first base material surface and the second base material surface of the adhesive sheet base material of the above embodiment is a given value or more, the adhesive sheet base materials are not easily adhered even when multiple sheets are stacked.

[0236] In addition, the sheet-like adhesive sheet can be provided in a state where multiple sheets are stacked. In this case, for example, the adhesive layer can be covered with the base material for the adhesive sheet of other stacked adhesive sheets.

[0237] In addition, the base material for the adhesive sheet and the adhesive sheet can be strip-shaped sheets and can be provided in a state where they are wound into a roll. The base material for the adhesive sheet and the adhesive sheet wound into a roll can be fed out from the roll and cut into a desired size or the like for use. Since at least one of the root mean square heights Rq of the first base material surface and the second base material surface of the base material for the adhesive sheet is a given value or more, even when wound into a roll, adhesion is less likely to occur and it is easy to feed out from the roll.

[0238] In addition, it can be provided in a state where the adhesive sheet is pre-cut into a desired size and the cut adhesive sheet is supported by a strip-shaped release sheet.

[0239] Examples

[0240] Hereinafter, the present invention will be described in more detail by way of examples. The present invention is not limited by any of these examples.

[0241] 〔Production of a base material (base material for adhesive sheet) with an oligomer sealing layer〕

[0242] [Example 1]

[0243] (1) Preparation of an oligomer sealant liquid for coating

[0244] An oligomer sealant liquid for coating of Example 1 (a coating liquid obtained by diluting the composition for the oligomer sealing layer with an organic solvent) was prepared by mixing the following (A) bisphenol A type epoxy compound, (B) polyester compound, (C) polyfunctional amine compound, and (D) acidic catalyst and stirring well.

[0245] (A) Bisphenol A type epoxy compound

[0246] "EPICLON H-360" (trade name) manufactured by DIC Corporation, solid content concentration: 40% by mass, weight average molecular weight: 25,000

[0247] (B) Polyester compound

[0248] "Byron GK680" (trade name) manufactured by Toyobo Co., Ltd., number average molecular weight: 6,000, glass transition temperature: 10°C

[0249] (C) Polyfunctional amine compound

[0250] Hexamethoxymethylmelamine, "CYMEL303" (trade name) manufactured by Nihon Cytec Industries Co., Ltd.

[0251] (D) Acid catalyst

[0252] Methanol solution of p - toluenesulfonic acid (solid component concentration: 50% by mass)

[0253] Specifically, 19.0 parts by mass of a toluene - diluted solution of the above (B) polyester compound (solid component concentration: 30% by mass) and 11.4 parts by mass of the above (C) hexamethoxymethyl melamine were added to 100 parts by mass of the above (A) bisphenol A - type epoxy compound, and further diluted with a mixed solvent of toluene / ethyl methyl ketone = 50% / 50% to prepare a solution with a solid component concentration of 3% by mass. The prepared solution was stirred, and 2.9 parts by mass of a methanol solution of (D) p - toluenesulfonic acid (solid component concentration: 50% by mass) was added to the stirred solution to obtain an oligomer sealant liquid for coating. It should be noted that the parts by mass are all values converted based on the solid components.

[0254] (2) Fabrication of the oligomer seal layer (fabrication of the substrate with the oligomer seal layer)

[0255] As the polyester film, a long annealed biaxially stretched polyethylene terephthalate film (manufactured by Teijin Film Solutions Co., Ltd., "Teijin Tetoron G2A" (trade name), thickness 25 μm) was prepared. Hereinafter, the annealed biaxially stretched polyethylene terephthalate film will also be simply referred to as the "annealed PET film". The annealed PET film was in a rolled state with a width of 1090 mm before use. The surface of the rolled annealed PET film facing the core side was defined as the first film surface, and the surface on the side opposite to the first film surface and facing the outermost side in the rolled state was defined as the second film surface.

[0256] The prepared oligomer sealant liquid for coating was uniformly coated on the first film surface of the annealed PET film by the wire bar coating method. The coated annealed PET film was passed through the inside of an oven to heat - cure the coating film, and a first oligomer seal layer with a thickness of 150 nm was formed on one side of the annealed PET film.

[0257] Next, a second oligomer seal layer with a thickness of 150 nm was also formed on the second film surface of the annealed PET film in the same manner as the first oligomer seal layer to obtain a substrate with oligomer seal layers on both sides. As the hot - air blowing conditions of the oven, the temperature was set at 150 °C and the wind speed was set at 8 m / min. As the processing speed in the oven, it was adjusted so that the annealed PET film coated with the oligomer sealant liquid for coating passed through the inside of the oven at a speed of 20 seconds.

[0258] (3) Fabrication of the adhesive sheet for electronic component processing

[0259] The following materials (polymer (polymer component), crosslinking agent, polyvalent low molecular weight compound having an energy ray polymerizable functional group, photoinitiator, and diluting solvent) were thoroughly stirred to prepare an adhesive liquid for coating (coating liquid for forming an adhesive layer).

[0260] Regarding the acrylate copolymer as the polymer (polymer component), 80.8 mass% of 2-ethylhexyl acrylate, 12.0 mass% of acryloylmorpholine (monomer having a nitrogen-containing functional group), 7.0 mass% of 4-hydroxybutyl acrylate, and 0.2 mass% of acrylic acid were copolymerized to prepare a polymer having a weight average molecular weight of 120,000, and 100 mass parts (solid content) were blended.

[0261] · Crosslinking agent: aliphatic isocyanate having hexamethylene diisocyanate [manufactured by Nippon Polyurethane Industry Co., Ltd.; Coronate HX], 7.4 mass parts (solid content)

[0262] · Polyvalent low molecular weight compound having an energy ray polymerizable functional group: propoxylated bisphenol A diacrylate [manufactured by Shin-Nakamura Chemical Co., Ltd.; A-BPP-3], 23.3 mass parts (solid content)

[0263] · Photoinitiator: 2-hydroxy-1-{4-[4-(2-hydroxy-2-methylpropanoyl)benzyl]phenyl}-2-methylpropan-1-one [manufactured by IGM Resin; Omnirad 127], 4.1 mass parts (solid content)

[0264] · Diluting solvent: ethyl acetate was used to adjust the solid content concentration of the adhesive liquid for coating to 30 mass%.

[0265] The prepared adhesive liquid for coating was coated on the release surface side of a release film [manufactured by Lintec Corporation; SP-PET382150] made of a transparent polyethylene terephthalate film with a thickness of 38 μm and having a silicone-based release layer, using a knife coater. Next, the coating film of the adhesive liquid for coating on the release film was heated at 90°C for 90 seconds, and then heated at 115°C for 90 seconds to dry the coating film. Then, the coating film was adhered to the second oligomer sealing layer of the substrate having oligomer sealing layers on both sides obtained through the above steps. Then, a high-pressure mercury lamp manufactured by EYE GRAPHICS was used as an ultraviolet irradiation device, and ultraviolet rays were irradiated on the coating film from the release film side under the conditions of an illuminance of 200 mW / cm 2 and an accumulated light amount of 200 mJ / cm 2 to produce an adhesive layer with a thickness of 50 μm. Thus, an adhesive sheet for electronic component processing was obtained.

[0266] [Example 2]

[0267] For the substrate with an oligomer sealing layer and the adhesive sheet for electronic component processing in Example 2, the solid content concentration of the oligomer sealant liquid coated only on the first film surface was changed to 5% by mass, and the thickness of the first oligomer sealing layer was changed to 200 nm. Otherwise, it was produced in the same manner as in Example 1.

[0268] [Comparative Example 1]

[0269] For the substrate with an oligomer sealing layer and the adhesive sheet for electronic component processing in Comparative Example 1, a polyester film (manufactured by Toray Industries, Inc., product name "X60K", thickness 50 μm) as an annealed PET film was used instead of the polyethylene terephthalate film used in Example 1. Otherwise, it was produced in the same manner as in Example 1.

[0270] [Comparative Example 2]

[0271] For the substrate with an oligomer sealing layer and the adhesive sheet for electronic component processing in Comparative Example 2, a biaxially stretched polyethylene terephthalate film (manufactured by Mitsubishi Chemical Corporation, product name "Diafoil T-100", thickness: 50 μm) that was not annealed was used instead of the polyethylene terephthalate film used in Example 1. Otherwise, it was produced in the same manner as in Example 1.

[0272] [Comparative Example 3]

[0273] For the substrate with an oligomer sealing layer and the adhesive sheet for electronic component processing in Comparative Example 3, the second oligomer sealing layer of Example 1 was not formed, and an adhesive layer was formed on the second film surface. Otherwise, it was produced in the same manner as in Example 1.

[0274] 〔Evaluation method〕

[0275] The evaluation of the substrate with an oligomer sealing layer was carried out according to the method shown below. The results are shown in Table 1.

[0276] · Root mean square height Rq and maximum cross-section height Rt

[0277] The maximum cross-sectional height Rt and root mean square height Rq of the first film surface and the second film surface of the polyester film, and the first substrate surface and the second substrate surface of the substrate with the oligomer sealing layer were measured using a contact surface roughness meter (product name "SV-3000") manufactured by Mitutoyo Corporation. For the measurement conditions of the maximum cross-sectional height Rt and root mean square height Rq, the measurements were carried out in accordance with JIS B0601:2001, JIS B 0632:2001, JIS B 0633:2001, and JIS B 0651:2001. In the measurement of Rt and Rq, the radius of the tip was 2 μm, and a stylus with a cone angle of 60 degrees was used.

[0278] · Excipitate evaluation

[0279] In Examples 1 and 2 and Comparative Examples 1 to 3, the substrate with the oligomer sealing layer (substrate for adhesive sheet) produced was heated at a temperature of 190°C for 1 hour. After heating, for Examples 1 and 2 and Comparative Examples 1 and 2, the surfaces of the first oligomer sealing layer and the second oligomer sealing layer were observed using an electron microscope (manufactured by KEYENCE Corporation, Digital Microscope; VHX-1000) to confirm the presence or absence of excipitates. For Comparative Example 3, the first oligomer sealing layer and the second film surface were similarly observed to confirm the presence or absence of excipitates. It should be noted that in Table 1, the second substrate surface in the excipitate evaluation of Comparative Example 3 can also be referred to as the second film surface.

[0280] The observation magnification when observing the presence or absence of excipitates was set to 500 times. The case where no excipitates were confirmed was judged as "A", and the case where excipitates were confirmed was judged as "B".

[0281] · Anti-blocking property

[0282] In the production of the substrate with the oligomer sealing layer, for Examples 1 and 2 and Comparative Examples 1 and 2, after forming the second oligomer sealing layer on the second film surface, and for Comparative Example 3, after forming the first oligomer sealing layer on the first film surface, when winding the substrate with the oligomer sealing layer on both sides around a core with a diameter of 153 mm, the evaluation was made on whether bubbles with a width of 10 mm or more were formed. It should be noted that the width of the bubble is the distance between the two farthest points in the contour of the bubble. The case where even one bubble with a width of 10 mm or more was formed was evaluated as B, and the case where no bubbles with a width of 10 mm or more were formed was evaluated as A.

[0283] · Heat shrinkage

[0284] The substrates with oligomer sealant layers prepared in Example 1, Example 2, and Comparative Examples 1 to 3 were left standing in a standard environment of 23°C and 50% relative humidity for 16 hours or more. Then, the measurement substrates were cut into squares with sides of 120 mm, and the MD direction and TD direction of the measurement substrates were made to coincide with the respective sides of the squares. Cross marks were made at positions 10 mm inside each side of the square and at the intersections of the straight lines parallel to each side of the square, thereby forming a mark of a square with sides of 100 mm as a specimen. By measuring the distance between the lines of the mark, two initial measurement values were obtained in the MD direction and TD direction of the measurement substrate, respectively. Subsequently, after heating the specimen at 190°C for 1 hour, it was left standing in a standard environment of 23°C and 50% relative humidity for 16 hours or more, and the distance between the lines of the mark was measured again. The thermal deformation amounts in the MD direction and TD direction of the measurement substrate were calculated respectively, and the amount reduced from the initial measurement value was divided by the initial measurement value and expressed as a percentage, thereby obtaining the value of the thermal shrinkage rate. For the thermal shrinkage rate, for the MD direction and TD direction respectively, it was the arithmetic mean of the values of the two sides of the square. When the distance increased, it was negative. The distance was measured using a reading microscope NRM-S3X.Y manufactured by Nippon Kogaku K.K.

[0285] · High-temperature process adaptability of adhesive sheets for electronic component processing

[0286] The release films were removed from the adhesive sheets for electronic component processing prepared in Example 1, Example 2, and Comparative Examples 1 to 3, and they were pasted onto an 8-inch silicon wafer ground to a thickness of 100 μm at room temperature using a laminating roller. Subsequently, after the adhesive sheets for electronic component processing pasted onto the wafer were treated by being stored in an environment of 100°C for 3 minutes, which was the condition of the assumed resin sealing process, they were left standing at room temperature for 16 hours for cooling. Then, the maximum warpage height of the wafer was measured with a ruler at room temperature. The case where the maximum warpage height was 5 mm or less was evaluated as A, and the case where it exceeded 5 mm was evaluated as B.

[0287]

[0288] The substrates with oligomer sealant layers in Example 1 and Example 2 were substrates as follows: Due to the low thermal shrinkage rate, they had excellent heat resistance. Since the evaluation of the precipitates was A, they could prevent contamination of the surfaces of components, devices, adherends, etc. even after undergoing a process under high-temperature conditions. Since the evaluation of the high-temperature process adaptability was A, they could reduce the influence caused by the deformation of the adhesive sheet due to high-temperature conditions. Moreover, since the evaluation of the anti-blocking property was A, they could also prevent blocking.

[0289] Both the root mean square heights Rq1 and Rq2 of the substrate with an oligomer sealant layer in Comparative Example 1 were less than 0.031 μm, and the evaluation of the anti-blocking property was B.

[0290] The substrate with the oligomer sealing layer of Comparative Example 2 was made of a polyester film that was not annealed, so it had a large heat shrinkage rate, and the evaluation of the adaptability to high-temperature processes was also B.

[0291] The substrate with the oligomer sealing layer of Comparative Example 3 did not have an oligomer sealing layer on the second substrate surface, so the evaluation of the precipitate was B.

Claims

1. A substrate for an adhesive sheet, which is used for processing electronic components, and the substrate for the adhesive sheet has: A polyester film having a first film surface and a second film surface on the side opposite to the first film surface, A first oligomer sealing layer provided on the first film surface, and A second oligomer sealing layer provided on the second film surface, The polyester film has been annealed. When the polyester film is heated at 190 °C for 1 hour, the thermal shrinkage rate of the annealed polyester film is 3% or less in the MD direction and 1% or less in the TD direction. The first oligomer sealing layer and the second oligomer sealing layer are each independently a cured film formed by curing an oligomer sealing layer forming composition containing a curable component. The first oligomer sealing layer and the second oligomer sealing layer substantially do not contain a filler. At least one of the root mean square height Rq1 of the surface of the first oligomer sealing layer on the side opposite to the surface facing the first film surface and the root mean square height Rq2 of the surface of the second oligomer sealing layer on the side opposite to the surface facing the second film surface is 0.031 μm or more and 0.1 μm or less. The thickness of the first oligomer sealing layer is 50 nm or more and 180 nm or less. The thickness of the second oligomer sealing layer is 50 nm or more and 180 nm or less.

2. The base material for the adhesive sheet according to claim 1, wherein, The polyester film is a polyethylene terephthalate film.

3. The base material for the adhesive sheet according to claim 1 or 2, wherein, The first oligomer sealing layer and the second oligomer sealing layer are each independently a cured film formed by curing an oligomer sealing layer composition containing (A) an epoxy compound and (C) a polyfunctional amine compound as curable components.

4. The base material for the adhesive sheet according to claim 1 or 2, wherein, At least one of the root mean square height Rq1 of the surface of the first oligomer sealing layer on the side opposite to the surface facing the first film surface and the root mean square height Rq2 of the surface of the second oligomer sealing layer on the side opposite to the surface facing the second film surface is 0.035 μm or more.

5. An adhesive sheet for processing electronic components, which has: The substrate for the adhesive sheet according to any one of claims 1 to 4, and An adhesive layer, The adhesive layer is provided on at least one of the surface of the first oligomer sealing layer on the side opposite to the surface facing the first film surface and the surface of the second oligomer sealing layer on the side opposite to the surface facing the second film surface.

6. The adhesive sheet for processing electronic components according to claim 5, wherein The adhesive layer contains an acrylic polymer, The acrylic polymer contains a structural unit derived from a monomer having a nitrogen-containing functional group, Wherein, the nitrogen-containing functional group does not contain an N-H bond.

7. The adhesive sheet for processing electronic components according to claim 6, wherein, The proportion of the structural unit derived from the monomer having a nitrogen-containing functional group in the total mass of the acrylic polymer is 9% by mass or more and 15% by mass or less.

8. The adhesive sheet for processing electronic components according to any one of claims 5 to 7, wherein, The adhesive layer contains a polymer of a polyvalent compound having an energy ray polymerizable functional group.

9. The adhesive sheet for processing electronic components according to any one of claims 5 to 7, wherein, The adhesive layer contains a compound having an unreacted energy ray polymerizable functional group.

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