JP6768038B2 - Adhesive sheet - Google Patents

Description

The present invention relates to an adhesive sheet.

In recent years, when miniaturization of semiconductor devices is required, CSP (Chip Size / Scale Package), which forms a semiconductor package having the same size as a built-in semiconductor element, has attracted attention as a semiconductor packaging technology. WLP (Wafer Level Package) is known as a semiconductor packaging technology for forming a particularly small and highly integrated package among CSPs. WLP is a technique for obtaining a semiconductor package by encapsulating a plurality of semiconductor chips at once with a sealing resin without using a substrate, and then cutting and separating each semiconductor chip. Generally, when semiconductor chips are collectively sealed, in order to prevent the semiconductor chips from moving, a plurality of semiconductor chips are temporarily fixed with a predetermined temporary fixing material, and the plurality of semiconductor chips are collectively sealed on the temporary fixing material. Seal in. After that, when cutting and separating into individual semiconductor chips (after batch sealing and before cutting and separating, or after cutting and separating), the temporary fixing material is peeled off from the structure containing the sealing resin and the semiconductor chip. As a temporary fixing material used in this way, a low-adhesive adhesive sheet is often used.

However, when a conventional pressure-sensitive adhesive sheet is used, there is a problem that adhesive residue is generated in the structure when it is peeled from the structure containing the sealing resin and the semiconductor chip. In particular, there is a problem that adhesive residue on the peripheral portion of the semiconductor chip becomes remarkable, and the adhesive residue causes a decrease in yield.

Japanese Unexamined Patent Publication No. 2001-308116 Japanese Unexamined Patent Publication No. 2001-313350

The present invention has been made to solve the above-mentioned conventional problems, and an object of the present invention is to have appropriate adhesiveness to a sealing resin and a semiconductor chip constituting a semiconductor package, and the sealing thereof. It is an object of the present invention to provide an adhesive sheet which can be easily peeled from a resin and a semiconductor chip and is less likely to leave adhesive residue at the time of peeling.

The pressure-sensitive adhesive sheet of the present invention is a pressure-sensitive adhesive sheet provided with a pressure-sensitive adhesive layer, and the contact angle of the surface of the pressure-sensitive adhesive layer with respect to 4-tertiary butylphenylglycidyl ether is 15 ° or more, and the pressure-sensitive adhesive sheet has a contact angle of 23 ° C. Adhesive strength to polyethylene terephthalate is 0.5 N / 20 mm or more.
In one embodiment, the sp value of the material constituting the pressure-sensitive adhesive in the pressure-sensitive adhesive layer is 7 (cal / cm ³ ) ^1/2 to 10 (cal / cm ³ ) ^1/2 .
In one embodiment, the probe tack value of the pressure-sensitive adhesive layer is 50 N / 5 mmφ or more.
In one embodiment, the pressure-sensitive adhesive layer comprises an acrylic pressure-sensitive adhesive.
In one embodiment, the acrylic pressure-sensitive adhesive comprises, as a base polymer, an acrylic polymer having an alkyl ester having 4 or more carbon atoms in the side chain.
In one embodiment, the content ratio of the structural unit having an alkyl ester having 4 or more carbon atoms in the side chain in the acrylic polymer is 30% by weight with respect to all the structural units constituting the acrylic polymer. That is all.
In one embodiment, the pressure-sensitive adhesive layer comprises a rubber-based pressure-sensitive adhesive.
In one embodiment, the pressure-sensitive adhesive layer comprises a silicone-based pressure-sensitive adhesive.
In one embodiment, the silicone-based pressure-sensitive adhesive contains a silicone rubber and a silicone resin as a base polymer, and the weight ratio of the silicone rubber to the silicone resin (rubber: resin) is 100: 0 to 100: 220. is there.
In one embodiment, the pressure-sensitive adhesive layer further comprises thermally expandable microspheres.
In one embodiment, the arithmetic surface roughness Ra of the pressure-sensitive adhesive layer before heating the heat-expandable microspheres is 500 nm or less.
In one embodiment, the pressure-sensitive adhesive sheet of the present invention is prepared by sticking the entire outer surface of the pressure-sensitive adhesive layer to a bakelite plate under an environmental temperature of 23 ° C., aging at an environmental temperature of 40 ° C. for 30 minutes, and then 1. When held for 2 hours while applying a load of 96 N, the deviation with respect to the bakelite plate is 0.5 mm or less.
In one embodiment, the pressure-sensitive adhesive sheet of the present invention further comprises a base material layer, and the pressure-sensitive adhesive layer is arranged on one side or both sides of the base material layer.
In one embodiment, the anchoring force between the base material layer and the pressure-sensitive adhesive layer is 6.0 N / 19 mm or more.

According to the present invention, by providing the pressure-sensitive adhesive layer having a contact angle of 15 ° or more with respect to 4-tertiary butylphenyl glycidyl ether, appropriate adhesiveness is provided to the sealing resin and the semiconductor chip constituting the semiconductor package. It is possible to obtain an adhesive sheet which has and can be easily peeled from the sealing resin and the semiconductor chip, and which is unlikely to leave adhesive residue at the time of peeling.

(A) is a figure explaining an example of the case where the conventional pressure-sensitive adhesive sheet is used for manufacturing a semiconductor package. (B) is a figure explaining an example in the case where the pressure-sensitive adhesive sheet of this invention is used for manufacturing a semiconductor package. (A) and (b) are schematic cross-sectional views of the pressure-sensitive adhesive sheet according to one embodiment of the present invention. It is the schematic sectional drawing of the pressure-sensitive adhesive sheet by one Embodiment of this invention.

A. Outline of Adhesive Sheet The adhesive sheet of the present invention includes an adhesive layer. The pressure-sensitive adhesive sheet of the present invention may be composed of only the pressure-sensitive adhesive layer, or may further include any suitable layer in addition to the pressure-sensitive adhesive layer. Examples of the layer other than the pressure-sensitive adhesive layer include a base material layer that can function as a support, a separator that is detachably arranged on the pressure-sensitive adhesive layer, and the like. Further, in addition to the above-mentioned pressure-sensitive adhesive layer, another pressure-sensitive adhesive layer may be further provided. Another pressure-sensitive adhesive layer may have a known structure.

The adhesive sheet of the present invention has an adhesive force against polyethylene terephthalate at 23 ° C., preferably 0.5 N / 20 mm or more, more preferably 0.5 N / 20 mm to 20 N / 20 mm, and further preferably 0.5 N / 20 mm. It is 20 mm to 15 N / 20 mm. In one embodiment, the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet of the present invention loses its adhesive strength by heating or light irradiation. In this case, the adhesive strength before reducing the adhesive strength is 2.5N / 20mm to 20N / 20mm. In the present specification, "adhesive strength against polyethylene terephthalate" means that an adhesive sheet (width 20 mm x length 100 mm) is bonded to a polyethylene terephthalate film (thickness 25 μm) (bonding condition: 2 kg roller 1). (Reciprocating), after being left at an ambient temperature of 23 ° C. for 30 minutes, the sample is subjected to a tensile test (peeling speed: 300 mm / min, peeling angle 180 °) to measure the adhesive strength.

The adhesive strength of the pressure-sensitive adhesive sheet of the present invention to a silicon wafer (thickness 500 μm) at 23 ° C. is preferably 0.1 N / 20 mm to 4 N / 20 mm, more preferably 0.15 N / 20 mm to 3 N / 20 mm, and further. It is preferably 0.2 N / 20 mm to 2/20 mm. Within such a range, an adhesive sheet having both adhesive strength and peelability to a semiconductor chip can be obtained. The adhesive strength to the silicon wafer can also be measured by the same method as the above-mentioned "adhesive strength to polyethylene terephthalate".

The adhesive strength of the pressure-sensitive adhesive sheet of the present invention to an epoxy resin sheet at 23 ° C. is preferably 0.1N / 20mm to 5N / 20mm, more preferably 0.3N / 20mm to 4N / 20mm, and even more preferably. It is 0.5 N / 20 mm to 3/20 mm. Within such a range, it is possible to suppress adhesive residue when peeling from the sealing resin (details will be described later). The adhesive strength to the epoxy resin film can also be measured by the same method as the above-mentioned "adhesive strength to polyethylene terephthalate". As the epoxy resin film, for example, a film composed of the sealing resin described in the evaluation of the "standoff suppressing effect" of the examples can be used.

The entire outer surface of the adhesive layer of the adhesive sheet (width 10 mm × length 150 mm) of the present invention is bonded to a bakelite plate (width 10 mm × length 125 mm) under an environmental temperature of 23 ° C., and 30 at an environmental temperature of 40 ° C. After aging for 1 minute and then holding for 2 hours while applying a load of 1.96 N, the deviation of the adhesive sheet with respect to the bakelite plate is preferably 0.5 mm or less, more preferably 0.4 mm or less. .. Here, the "deviation of the adhesive sheet with respect to the bakelite plate" means the amount of movement of the adhesive sheet from the initial state with reference to the state before aging (initial state). The pressure-sensitive adhesive sheet having a small amount of deviation is a pressure-sensitive adhesive sheet in which the pressure-sensitive adhesive layer is unlikely to undergo cohesive failure, and such a pressure-sensitive adhesive sheet is essentially a pressure-sensitive adhesive sheet in which adhesive remains. With such an adhesive sheet, the effect of the present invention becomes remarkable. The pressure-sensitive adhesive layer, which is unlikely to undergo cohesive breakdown, is formed by using, for example, the above-mentioned acrylic pressure-sensitive adhesive (preferably a pressure-sensitive adhesive containing a crosslinked acrylic polymer as a base polymer) as the pressure-sensitive adhesive for forming the pressure-sensitive adhesive layer. can do. Further, a rubber-based pressure-sensitive adhesive is used as the pressure-sensitive adhesive, and more specifically, it contains a base polymer (rubber) constituting the rubber-based pressure-sensitive adhesive, a hydroxyl group-containing polyolefin, and a cross-linking agent capable of reacting with the hydroxyl group of the hydroxyl group polyolefin. By using a rubber-based pressure-sensitive adhesive (Rub1) and appropriately adjusting the blending amounts of the hydroxyl group-containing polyolefin and the cross-linking agent, a pressure-sensitive adhesive layer that is unlikely to undergo coagulation failure can be formed. Details will be described later.

The thickness of the pressure-sensitive adhesive sheet of the present invention is preferably 3 μm to 300 μm, more preferably 5 μm to 150 μm, and even more preferably 10 μm to 100 μm.

B. Adhesive layer The adhesive layer has a surface contact angle with respect to 4-tertiary butylphenylglycidyl ether of 15 ° or more, more preferably 20 ° or more, still more preferably 30 ° to 100 °. , Particularly preferably 40 ° to 60 °.

The adhesive layer of the pressure-sensitive adhesive sheet of the present invention has an adjusted affinity for a sealing resin (for example, an epoxy resin) used for sealing a semiconductor chip and a monomer component constituting the sealing resin. Specifically, the pressure-sensitive adhesive layer is adjusted so that its affinity is low within a range in which it can exhibit appropriate adhesiveness to the sealing resin (and semiconductor chip). The adhesive layer having an appropriately adjusted affinity has a contact angle with respect to 4-tertiary butylphenylglycidyl ether in the above range. By adjusting the affinity for the sealing resin and the monomer components constituting the sealing resin in this way, there is little adhesive residue, and more specifically, the semiconductor and the resin that seals the semiconductor (or the resin). A pressure-sensitive adhesive sheet capable of reducing the pressure-sensitive adhesive layer component adhering to the structure when the structure (FIG. 1) containing the precursor monomer) is attached and then peeled off can be obtained. The mechanism by which the adhesive residue is reduced by using the pressure-sensitive adhesive sheet of the present invention is considered as follows.

FIG. 1A shows an example of the case where the conventional pressure-sensitive adhesive sheet 10'is used for manufacturing a semiconductor package. The pressure-sensitive adhesive sheet 10'has a pressure-sensitive adhesive layer, and the outer surface of the pressure-sensitive adhesive layer is used as a sticking surface. Conventionally, in the manufacture of a semiconductor package (CSP), first, the semiconductor chip 1 is attached to the adhesive sheet 10'(ai). Then, the composition 2'containing the monomer which is the precursor of the sealing resin 2 is applied (a-ii) so as to seal the semiconductor chip 1, and then the composition 2'is cured (a). -Iii). As the above composition, for example, a composition containing a naphthalene type bifunctional epoxy resin (epoxy equivalent: 144) is used. Next, the adhesive sheet 10'is peeled from the structure 20 containing the semiconductor chip 1 and the sealing resin 2 before the semiconductor chips are individually cut and separated or after the semiconductor chips are cut and separated (in the illustrated example, before the cutting and separation). (A-iv). When a conventional adhesive sheet is used, adhesive residue is likely to occur at the time of peeling. In particular, adhesive residue is remarkably observed in the peripheral portion of the semiconductor chip 1. When the conventional adhesive sheet 10'is used, the inventors of the present invention swell the adhesive layer of the adhesive sheet 10'at the time of peeling so as to surround the bottom of the semiconductor chip 1, and the adhesive sheet 10'at the time of peeling It has been found that a step (hereinafter, also referred to as stand-off) due to the bottom surface of the semiconductor chip 1 is formed in the pressure-sensitive adhesive layer. It is considered that the stress derived from the semiconductor chip 1 is concentrated on the standoff portion, so that the pressure-sensitive adhesive layer is coagulated and broken, and as a result, the adhesive residue is generated.

FIG. 1B shows an example of the case where the pressure-sensitive adhesive sheet 10 of the present invention is used for manufacturing a semiconductor package. The pressure-sensitive adhesive sheet 10 has a pressure-sensitive adhesive layer, and the outer surface of the pressure-sensitive adhesive layer is used as a sticking surface. In FIG. 1B, a structure containing the semiconductor chip 1 and the sealing resin 2 on the adhesive sheet 10 by the same operation as shown in FIG. 1A except that the adhesive sheet is changed. 20 is formed, and then the adhesive sheet 10 is peeled off. When the pressure-sensitive adhesive sheet 10 of the present invention is used, the standoff that occurs in the pressure-sensitive adhesive sheet 10 is extremely small (or does not occur), and the adhesive residue is suppressed.

In the conventional pressure-sensitive adhesive sheet 10', the pressure-sensitive adhesive layer component is transferred to the composition containing the monomer that is the precursor of the sealing resin 2 or the sealing resin, and as a result, the resin layer of the pressure-sensitive adhesive sheet 10'is a semiconductor. It is considered that a swelling standoff occurs so as to surround the bottom of the chip 1. The presence or absence of component transfer can be confirmed by spectroscopic analysis by FT-IR or the like. On the other hand, in the present invention, since the pressure-sensitive adhesive layer has an adjusted affinity for the sealing resin used for sealing the semiconductor chip and the monomer components constituting the sealing resin, the above-mentioned components It is believed that migration is suppressed and standoffs are minimized (or do not occur), resulting in reduced adhesive residue. Hereinafter, in the present specification, a sealing resin used for sealing a semiconductor chip and a monomer component constituting the sealing resin are collectively referred to as a sealing material.

The pressure-sensitive adhesive layer contains a pressure-sensitive adhesive. The sp value of the material (polymer) constituting the pressure-sensitive adhesive is preferably 7 (cal / cm ³ ) ^1/2 to 10 (cal / cm ³ ) ^1/2 , and more preferably 7 (cal / cm ³ ). ^{It is 1/2 to} 9.1 (cal / cm ³ ) ^1/2 , and more preferably 7 (cal / cm ³ ) ^1/2 to 8 (cal / cm ³ ) ^1/2 . Within such a range, it is possible to form an adhesive layer having appropriate adhesiveness, having a low affinity with the sealing material, and hardly causing standoffs. The pressure-sensitive adhesive sheet provided with such a pressure-sensitive adhesive layer is unlikely to leave adhesive residue. The materials constituting the pressure-sensitive adhesive here are the base polymer (base polymer after cross-linking when cross-linked) and rubber (rubber after cross-linking when cross-linked) contained in the pressure-sensitive adhesive. , Means a polymer such as a tackifier. In the present invention, at least the sp value of the base polymer (base polymer after cross-linking in the case of cross-linking) or rubber (rubber after cross-linking in the case of cross-linking), which is the main component of the pressure-sensitive adhesive, is within the above range. It is preferable to have.

In one embodiment, 1,3-bis (N, N-glycidylaminomethyl) cyclohexane is brought into contact with the surface of the pressure-sensitive adhesive layer and left in an environment of 50 ° C. for 2 hours, and the surface of the pressure-sensitive adhesive is subjected to FT. When the absorbance of the glycidyl group-derived peak is measured by −IR measurement, the absorbance ratio of the glycidyl group-derived peak is preferably 1.3 or less with respect to the absorbance of the glycidyl group-derived peak of the initial pressure-sensitive adhesive layer. , More preferably 1.1 or less, still more preferably 1.05 or less. The "initial pressure-sensitive adhesive layer" means a pressure-sensitive adhesive layer before contact with 1,3-bis (N, N-dicrysidylaminomethyl) cyclohexane. In another embodiment, the surface of the pressure-sensitive adhesive layer is brought into contact with 1,3-bis (N, N-diglycidylaminomethyl) cyclohexane and left in an environment of 50 ° C. for 2 hours to allow FT- on the surface of the pressure-sensitive adhesive. When IR measurement (for example, attenuated total reflection method (ATR method)) is performed, the amount of increase from the initial pressure-sensitive adhesive layer with respect to the absorbance at the wave number (around 850 cm ^-1 ) at which the glycidyl group-derived peak occurs is preferably 0. It is 3 or less, more preferably 0.1 or less. Here, 1,3-bis (N, N-dicrysidylaminomethyl) cyclohexane is an epoxy compound that can be used as a material for a resin for encapsulating a semiconductor chip. If the epoxy compound forms an adhesive layer that is difficult to transfer even when the epoxy compound is brought into contact with the epoxy compound as described above, a pressure-sensitive adhesive sheet that is less likely to cause standoffs and has less adhesive residue even when used in the manufacture of semiconductor packages can be obtained. be able to.

The thickness of the pressure-sensitive adhesive layer is preferably 1 μm to 300 μm, more preferably 3 μm to 300 μm, further preferably 5 μm to 150 μm, still more preferably 10 μm to 100 μm, still more preferably 10 μm to 50 μm. is there. As will be described later, when the pressure-sensitive adhesive layer contains heat-expandable microspheres, the thickness of the pressure-sensitive adhesive layer is preferably 3 μm to 300 μm, more preferably 5 μm to 150 μm, and 10 μm to 100 μm. Is even more preferable. Within such a range, an adhesive layer having excellent surface smoothness and excellent adhesion can be formed. When the pressure-sensitive adhesive layer does not contain thermal-expandable microspheres, the thickness of the pressure-sensitive adhesive layer is preferably 50 μm or less, more preferably 1 μm to 50 μm, and even more preferably 5 μm to 30 μm.

The elastic modulus of the pressure-sensitive adhesive layer by the nanoindentation method at 25 ° C. is preferably less than 100 MPa, more preferably 0.1 MPa to 50 MPa, and further preferably 0.1 MPa to 10 MPa. Within such a range, an adhesive sheet having an appropriate adhesive strength can be obtained as an adhesive sheet that can be used in the manufacture of semiconductor packages. The elastic modulus by the nanoindentation method is the load-bearing-pushing depth obtained by continuously measuring the load on the indenter and the pushing depth when the indenter is pushed into the sample during loading and unloading. The elastic modulus obtained from the curve. In the present specification, the elastic modulus by the nanoindentation method means the elastic modulus measured as described above under the measurement conditions of load: 1 mN, load / unloading speed: 0.1 mN / s, and holding time: 1s.

The tensile elastic modulus of the pressure-sensitive adhesive layer at 25 ° C. is preferably less than 100 MPa, more preferably 0.1 MPa to 50 MPa, and even more preferably 0.1 MPa to 10 MPa. Within such a range, an adhesive sheet having an appropriate adhesive strength can be obtained as an adhesive sheet that can be used in the manufacture of semiconductor packages. The tensile elastic modulus can be measured according to JIS K 7161: 2008.

The probe tack value of the pressure-sensitive adhesive layer is preferably 50 N / 5 mmφ or more, more preferably 75 N / 5 mmφ or more, and further preferably 100 N / 5 mmφ or more. Within such a range, the retention of the adherend is excellent, and for example, when the semiconductor chip is temporarily fixed, unnecessary misalignment of the semiconductor chip can be prevented. The method for measuring the probe tack value will be described later.

<Adhesive>
As the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer, any suitable pressure-sensitive adhesive can be used as long as the effects of the present invention can be obtained. Preferably, a pressure-sensitive adhesive containing a base polymer having an sp value in the above range is used. Examples of the pressure-sensitive adhesive include an acrylic pressure-sensitive adhesive, a rubber-based pressure-sensitive adhesive, and a silicone-based pressure-sensitive adhesive. Among them, an acrylic pressure-sensitive adhesive may be preferably used. Further, as the pressure-sensitive adhesive, an active energy ray-curable pressure-sensitive adhesive may be used.

(Acrylic adhesive)
The acrylic pressure-sensitive adhesive includes, for example, an acrylic pressure-sensitive adhesive based on an acrylic polymer (homopolymer or copolymer) using one or more (meth) acrylic acid alkyl esters as a monomer component. And so on.

The acrylic polymer preferably has an alkyl ester having 4 or more carbon atoms as a side chain, more preferably has an alkyl ester having 6 or more carbon atoms, and has an alkyl ester having 8 or more carbon atoms. Is more preferable, and it is particularly preferable to have an alkyl ester having 8 to 20 carbon atoms, and most preferably to have an alkyl ester having 8 to 18 carbon atoms. By using an acrylic polymer having a long side chain, it is possible to form an adhesive layer having a low affinity with the sealing material. In the acrylic polymer, the content ratio of the structural unit having an alkyl ester having 4 or more carbon atoms as a side chain is preferably 30% by weight or more with respect to all the structural units constituting the acrylic polymer, and more. It is preferably 50% by weight or more, more preferably 70% by weight to 100% by weight, and particularly preferably 80% by weight to 100% by weight. Within such a range, a pressure-sensitive adhesive layer having a low affinity with the sealing material can be formed.

The acrylic pressure-sensitive adhesive may contain a plurality of types of acrylic polymers, but the content ratio of the acrylic polymer having an alkyl SL having 4 or more carbon atoms in the side chain is 100 parts by weight of the total acrylic polymer. , It is preferably 30 parts by weight to 100 parts by weight, and more preferably 70 parts by weight to 100 parts by weight.

Specific examples of the above (meth) acrylic acid alkyl ester include methyl (meth) acrylic acid, ethyl (meth) acrylic acid, propyl (meth) acrylic acid, isopropyl (meth) acrylic acid, and butyl (meth) acrylic acid. Isobutyl acrylate, s-butyl (meth) acrylate, t-butyl (meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, (meth) acrylate Octyl, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, nonyl (meth) acrylate, isononyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, (meth) acrylic Undecyl acid, dodecyl (meth) acrylate, tridecyl (meth) acrylate, tetradecyl (meth) acrylate, pentadecyl (meth) acrylate, hexadecyl (meth) acrylate, heptadecyl (meth) acrylate, (meth) acrylate Examples thereof include (meth) acrylic acid C1-20 alkyl esters such as octadecyl, nonadecil (meth) acrylic acid, and eicosyl (meth) acrylic acid. Of these, a (meth) acrylic acid alkyl ester having a linear or branched alkyl group having 4 to 20 carbon atoms (more preferably 6 to 20, particularly preferably 8 to 18) is preferable. Is 2-ethylhexyl (meth) acrylate.

The acrylic polymer is a unit corresponding to other monomer components copolymerizable with the (meth) acrylic acid alkyl ester, if necessary, for the purpose of modifying cohesive force, heat resistance, crosslinkability, etc. May include. Examples of such monomer components include carboxyl group-containing monomers such as acrylic acid, methacrylic acid, carboxyethyl acrylate, carboxypentyl acrylate, itaconic acid, maleic acid, fumaric acid, and crotonic acid; maleic anhydride and icotanic anhydride. Acid anhydride monomers such as; (meth) hydroxyethyl acrylate, (meth) hydroxypropyl acrylate, (meth) hydroxybutyl acrylate, (meth) hydroxyhexyl acrylate, (meth) hydroxyoctyl acrylate, (meth) Hydrolyl group-containing monomers such as hydroxydecyl acrylate, hydroxylauryl (meth) acrylate, and (4-hydroxymethylcyclohexyl) methylmethacrylate; styrene sulfonic acid, allyl sulfonic acid, 2- (meth) acrylamide-2-methylpropan sulfonic acid. , (Meta) acrylamide propanesulfonic acid, sulfopropyl (meth) acrylate, (meth) acryloyloxynaphthalene sulfonic acid and other sulfonic acid group-containing monomers; (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N-butyl (N-substituted) amide-based monomers such as (meth) acrylamide, N-methylol (meth) acrylamide, N-methylolpropane (meth) acrylamide; aminoethyl (meth) acrylate, N, N-dimethyl (meth) acrylate Aminoalkyl-based (meth) acrylate monomers such as aminoethyl and t-butylaminoethyl (meth) acrylate; alkoxyalkyl-based (meth) acrylates such as methoxyethyl (meth) acrylate and ethoxyethyl (meth) acrylate. Monomers; Maleimide-based monomers such as N-cyclohexyl maleimide, N-isopropyl maleimide, N-lauryl maleimide, N-phenylmaleimide; N-methylitaconimide, N-ethylitaconimide, N-butylitaconimide, N-octylitaconimide , N-2-ethylhexylitaconimide, N-cyclohexylitaconimide, N-laurylitaconimide and other itaconimide-based monomers; N- (meth) acryloyloxymethylene succinimide, N- (meth) acurloyl-6-oxyhexamethylene succinimide, Succinimide-based monomers such as N- (meth) acryloyl-8-oxyoctamethylene succinimide; vinyl acetate, vinyl propionate, N-vinylpyrrolidone, methylvinylpyro Vinyls such as lidone, vinylpyridine, vinylpiperidone, vinylpyrimidine, vinylpiperazin, vinylpyrazine, vinylpyrrole, vinylimidazole, vinyloxazole, vinylmorpholin, N-vinylcarboxylic acid amides, styrene, α-methylstyrene, N-vinylcaprolactam Monomer; Cyanoacrylate monomer such as acrylonitrile and methacrylonitrile; Epoxy group-containing acrylic monomer such as glycidyl (meth) acrylate; Polyethylene glycol (meth) acrylate, Polypropylene glycol (meth) acrylate, (meth) acrylic acid Glycol-based acrylic ester monomers such as methoxyethylene glycol and methoxypolypropylene glycol (meth) acrylate; heterocycles such as tetrahydrofurfuryl (meth) acrylate, fluorine (meth) acrylate and silicone (meth) acrylate, halogen atoms and silicon atoms. Acrylic acid ester-based monomers having the above; hexanediol di (meth) acrylate, (poly) ethylene glycol di (meth) acrylate, (poly) propylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, pentaerythritol Polyfunctional monomers such as di (meth) acrylate, trimethylolpropantri (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, epoxy acrylate, polyester acrylate, urethane acrylate; isoprene, butadiene, Olefin-based monomers such as isobutylene; vinyl ether-based monomers such as vinyl ether and the like can be mentioned. These monomer components may be used alone or in combination of two or more. Among the above, a carboxyl group-containing monomer (particularly preferably acrylic acid) or a hydroxyl group-containing monomer (particularly preferably hydroxyethyl (meth) acrylate) is preferable. The content of the structural unit derived from the carboxyl group-containing monomer is preferably 0.1% by weight to 10% by weight, more preferably 0.5% by weight to 5% by weight, based on all the structural units constituting the acrylic polymer. By weight%, particularly preferred is 1% to 4% by weight. The content of the structural unit derived from the hydroxyl group-containing monomer is preferably 0.1% by weight to 20% by weight, more preferably 0.5% by weight, based on all the structural units constituting the acrylic polymer. It is 10% by weight, and particularly preferably 1% by weight to 7% by weight.

The acrylic pressure-sensitive adhesive may contain any suitable additive, if desired. Examples of the additive include a cross-linking agent, a tackifier, a plasticizer (for example, a trimellitic acid ester-based plasticizer, a pyromellitic acid ester-based plasticizer, etc.), a pigment, a dye, a filler, an antistatic agent, and a conductive agent. Examples thereof include materials, antistatic agents, ultraviolet absorbers, light stabilizers, release modifiers, softeners, surfactants, flame retardants, antioxidants and the like.

Examples of the cross-linking agent contained in the acrylic pressure-sensitive adhesive include isocyanate-based cross-linking agents, epoxy-based cross-linking agents, melamine-based cross-linking agents, peroxide-based cross-linking agents, urea-based cross-linking agents, and metal alkoxide-based cross-linking agents. Examples thereof include metal chelate-based cross-linking agents, metal salt-based cross-linking agents, carbodiimide-based cross-linking agents, oxazoline-based cross-linking agents, aziridine-based cross-linking agents, and amine-based cross-linking agents. Of these, an isocyanate-based cross-linking agent or an epoxy-based cross-linking agent is preferable.

Specific examples of the isocyanate-based cross-linking agent contained in the acrylic pressure-sensitive adhesive include lower aliphatic polyisocyanates such as butylene diisocyanate and hexamethylene diisocyanate; and alicyclic such as cyclopentylene diisocyanate, cyclohexylene diisocyanate, and isophorone diisocyanate. Group isocyanates; aromatic isocyanates such as 2,4-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, xylylene diisocyanate; trimethylolpropane / tolylene diisocyanate trimer adduct (manufactured by Nippon Polyurethane Industry Co., Ltd., product) Name "Coronate L"), Trimethylol propane / hexamethylene diisocyanate trimeric adduct (manufactured by Nippon Polyurethane Industry Co., Ltd., trade name "Coronate HL"), isocyanurate of hexamethylene diisocyanate (manufactured by Nippon Polyurethane Industry Co., Ltd., product) Isocyanate adducts such as the name "Coronate HX"); etc. The content of the isocyanate-based cross-linking agent can be set to an arbitrary appropriate amount according to the desired adhesive strength, and is typically 0.1 to 20 parts by weight with respect to 100 parts by weight of the base polymer. It is more preferably 0.5 parts by weight to 10 parts by weight.

Examples of the epoxy-based cross-linking agent contained in the acrylic pressure-sensitive adhesive include N, N, N', N'-tetraglycidyl-m-xylene diamine, diglycidyl aniline, and 1,3-bis (N, N-). Glycidylaminomethyl) cyclohexane (manufactured by Mitsubishi Gas Chemicals, trade name "Tetrad C"), 1,6-hexanediol diglycidyl ether (manufactured by Kyoeisha Chemicals, trade name "Epolite 1600"), neopentyl glycol diglycidyl ether (manufactured by Kyoeisha Chemical Co., Ltd., trade name "Epolite 1600") Kyoeisha Chemical Co., Ltd., trade name "Epolite 1500NP"), ethylene glycol diglycidyl ether (Kyoeisha Chemical Co., Ltd., trade name "Epolite 40E"), propylene glycol diglycidyl ether (Kyoeisha Chemical Co., Ltd., trade name "Epolite 70P") , Polyethylene glycol diglycidyl ether (manufactured by Nippon Yushi Co., Ltd., trade name "Epiol E-400"), Polypropylene glycol diglycidyl ether (manufactured by Nippon Yushi Co., Ltd., trade name "Epiol P-200"), Sorbitol polyglycidyl ether (Nagasechem) Tex, trade name "Denacol EX-611"), glycerol polyglycidyl ether (Nagasechemtex, trade name "Denacol EX-314"), pentaerythritol polyglycidyl ether, polyglycerol polyglycidyl ether (Nagasechemtex) Made by the company, trade name "Denacol EX-512"), sorbitan polyglycidyl ether, trimethylolpropane polyglycidyl ether, adipate diglycidyl ester, o-phthalic acid diglycidyl ester, triglycidyl-tris (2-hydroxyethyl) isocia Examples thereof include nurate, resorcin diglycidyl ether, bisphenol-S-diglycidyl ether, and epoxy resins having two or more epoxy groups in the molecule. The content of the epoxy-based cross-linking agent can be set to an arbitrary appropriate amount according to the desired adhesive strength, and is typically 0.01 parts by weight to 10 parts by weight with respect to 100 parts by weight of the base polymer. It is more preferably 0.03 part by weight to 5 parts by weight.

As the tackifier contained in the acrylic pressure-sensitive adhesive, any appropriate tackifier is used. As the tackifier, for example, a tackifier resin is used. Specific examples of the tackifier resin include rosin-based tackifier resins (eg, unmodified rosin, modified rosin, rosinphenol-based resins, rosin ester-based resins, etc.) and terpene-based tackifier resins (eg, terpene-based resins, terpenes). Phenolic resin, styrene-modified terpene resin, aromatic-modified terpene resin, hydrogenated terpene resin), hydrocarbon-based tackifier resin (for example, aliphatic hydrocarbon resin, aliphatic cyclic hydrocarbon resin, aromatic) Hydrocarbon resins (for example, styrene resins, xylene resins, etc.), aliphatic / aromatic petroleum resins, aliphatic / alicyclic petroleum resins, hydrogenated hydrocarbon resins, kumaron resins, kumaron inden Resins, etc.), phenol-based tackifier resins (eg, alkylphenol-based resins, xyleneformaldehyde-based resins, resoles, novolak, etc.), ketone-based tackifier resins, polyamide-based tackifier resins, epoxy-based tackifier resins, elastomer-based tackifier resins. And so on. Of these, a rosin-based tackifier resin, a terpene-based tackifier resin, or a hydrocarbon-based tackifier resin (styrene resin, etc.) is preferable. The tackifier may be used alone or in combination of two or more. The amount of the tackifier added is preferably 5 parts by weight to 100 parts by weight, and more preferably 10 parts by weight to 50 parts by weight with respect to 100 parts by weight of the base polymer.

Preferably, as the tackifier resin, a resin having a high softening point or a glass transition temperature (Tg) is used. By using a resin having a high softening point or glass transition temperature (Tg), a pressure-sensitive adhesive layer capable of exhibiting high adhesiveness is formed even in a high-temperature environment (for example, in a high-temperature environment during processing during semiconductor chip encapsulation). can do. The softening point of the tackifier is preferably 100 ° C. to 180 ° C., more preferably 110 ° C. to 180 ° C., and even more preferably 120 ° C. to 180 ° C. The glass dislocation temperature (Tg) of the tackifier is preferably 100 ° C. to 180 ° C., more preferably 110 ° C. to 180 ° C., and even more preferably 120 ° C. to 180 ° C.

Preferably, a low-polarity tackifier resin is used as the tackifier resin. By using a low-polarity tackifier resin, a pressure-sensitive adhesive layer having a low affinity with the sealing material can be formed. Examples of the low-polarity tackifier resin include aliphatic hydrocarbon resins, aliphatic cyclic hydrocarbon resins, aromatic hydrocarbon resins (for example, styrene resins, xylene resins, etc.), and aliphatic hydrocarbons. Examples thereof include aromatic petroleum resins, aliphatic / alicyclic petroleum resins, and hydrocarbon-based hydrocarbon resins. Of these, a tackifier having 5 to 9 carbon atoms is preferable. This is because such a pressure-sensitive adhesive has low polarity, is excellent in compatibility with an acrylic polymer, does not undergo phase separation in a wide temperature range, and can form a pressure-sensitive adhesive layer having excellent stability. ..

The acid value of the tackifier resin is preferably 40 or less, more preferably 20 or less, and even more preferably 10 or less. Within such a range, a pressure-sensitive adhesive layer having a low affinity with the sealing material can be formed. The hydroxyl value of the tackifier resin is preferably 60 or less, more preferably 40 or less, and further preferably 20 or less. Within such a range, a pressure-sensitive adhesive layer having a low affinity with the sealing material can be formed.

(Rubber adhesive)
As the rubber-based pressure-sensitive adhesive, any suitable pressure-sensitive adhesive can be used as long as the effects of the present invention can be obtained. Examples of the rubber-based pressure-sensitive adhesive include natural rubber; polyisoprene rubber, butadiene rubber, styrene-butadiene (SB) rubber, styrene-isoprene (SI) rubber, styrene-isoprene-styrene block copolymer (SIS) rubber, and styrene. -Butadiene-styrene block copolymer (SBS) rubber, styrene-ethylene-butylene-styrene block copolymer (SEBS) rubber, styrene-ethylene-propylene-styrene block copolymer (SEPS) rubber, styrene-ethylene-propylene A rubber-based pressure-sensitive adhesive based on block copolymer (SEP) rubber, recycled rubber, butyl rubber, polyisobutylene rubber, or synthetic rubber such as a modified product thereof; is preferably used. These base polymers (rubbers) have a low sp value, and by using the base polymer, it is possible to form an adhesive layer having a low affinity with a sealing material.

Polyisobutylene rubber, polyisoprene rubber, or butyl rubber is particularly preferably used as the base polymer constituting the rubber-based pressure-sensitive adhesive. By using these rubbers, it is possible to form an adhesive layer having excellent semiconductor chip retention at room temperature and excellent peelability. In addition, an adhesive layer having a low affinity with the sealing material can be formed.

As the base polymer constituting the rubber-based pressure-sensitive adhesive, styrene / ethylene / propylene block copolymer (SEP) rubber, styrene / ethylene / butylene / styrene block copolymer (SEBS) rubber, styrene / isoprene / styrene block common weight Combined (SIS) rubber, styrene-butadiene-styrene block copolymer (SBS) rubber, and propylene rubber may also be preferably used. By using these rubbers, it is possible to form an adhesive layer capable of exhibiting high adhesiveness even in a high temperature environment (for example, in a high temperature environment in processing at the time of encapsulating a semiconductor chip). In the base polymer (rubber) having a styrene-derived structural unit, the content ratio of the styrene-derived structural unit is preferably 15% by weight or more with respect to all the structural units in the base polymer.

The rubber-based pressure-sensitive adhesive may contain any suitable additive, if necessary. Examples of the additive include a cross-linking agent, a vulcanizing agent, a tackifier, a plasticizer, a pigment, a dye, a filler, an antiaging agent, a conductive material, an antistatic agent, an ultraviolet absorber, a light stabilizer, and peeling adjustment. Examples thereof include agents, softeners, surfactants, flame retardants, antioxidants and the like.

As the pressure-sensitive adhesive contained in the rubber-based pressure-sensitive adhesive, any appropriate pressure-sensitive adhesive is used. As the tackifier, for example, a tackifier resin is used. Specific examples of the tackifier resin include rosin-based tackifier resins, rosin derivative resins, petroleum-based resins, terpene-based resins, and ketone-based resins. The amount of the tackifier added is preferably 5 parts by weight to 100 parts by weight, and more preferably 10 parts by weight to 50 parts by weight with respect to 100 parts by weight of the base polymer.

Examples of the rosin-based resin contained in the rubber-based pressure-sensitive adhesive include gum rosin, wood rosin, and tall rosin. As the rosin-based resin, stabilized rosin obtained by disproportionating or hydrogenating any suitable rosin may be used. Further, as the rosin-based resin, it was obtained by modifying a polymerized rosin, which is a multimer (typically a dimer) of an arbitrary appropriate rosin, or an arbitrary appropriate rosin (for example, denaturing with an unsaturated acid). Modified rosin may be used.

Examples of the rosin derivative resin contained in the rubber-based pressure-sensitive adhesive include an esterified product of the rosin-based resin, a phenol-modified product of the rosin-based resin, and an esterified product of the phenol-modified rosin-based resin.

Examples of the petroleum-based resin contained in the rubber-based pressure-sensitive adhesive include aliphatic petroleum resins, aromatic petroleum resins, copolymer petroleum resins, alicyclic petroleum resins, and hydrides thereof. ..

Examples of the terpene resin contained in the rubber adhesive include α-pinene resin, β-pinene resin, aromatic-modified terpene resin, terpene phenol resin and the like.

Examples of the ketone resin contained in the rubber adhesive include a ketone resin obtained by condensing ketones (for example, an aliphatic ketone and an alicyclic ketone) with formaldehyde.

Examples of the cross-linking agent contained in the rubber-based pressure-sensitive adhesive include isocyanate-based cross-linking agents. Examples of the vulcanizing agent contained in the rubber-based pressure-sensitive adhesive include a thiuram-based vulcanizing agent, a quinoid-based vulcanizing agent, and a quinone-dioxime-based vulcanizing agent. If the rubber-based pressure-sensitive adhesive contains a cross-linking agent and / or a vulcanizing agent, a pressure-sensitive adhesive layer having high cohesiveness and less adhesive residue can be formed. The total content of the cross-linking agent and the vulcanizing agent is typically 0.1 to 20 parts by weight, more preferably 0.1 to 10 parts by weight, based on 100 parts by weight of the base polymer. is there.

In one embodiment, a rubber-based pressure-sensitive adhesive (Rub1) containing the base polymer (rubber), a hydroxyl group-containing polyolefin, and a cross-linking agent a capable of reacting with the hydroxyl group of the hydroxyl group polyolefin is used. In this rubber-based pressure-sensitive adhesive, the base polymer is not directly crosslinked, but the base polymer and the crosslinked hydroxyl group-containing polyolefin are entangled, so that so-called pseudo-crosslinking is performed. As a result, a pressure-sensitive adhesive layer having high cohesiveness and less adhesive residue can be formed. As the base polymer (rubber) used in this embodiment, the above-mentioned synthetic rubber is preferably used. Further, as the cross-linking agent used in this embodiment, an isocyanate-based cross-linking agent is preferably used.

The blending amount of the hydroxyl group-containing polyolefin is preferably 0.5 parts by weight or more, more preferably 1 part by weight, based on 100 parts by weight of the total of the base polymer (rubber), the hydroxyl group-containing polyolefin, and the cross-linking agent a. It is 0.0 parts by weight or more. Within such a range, a highly cohesive pressure-sensitive adhesive layer can be formed. Further, when the pressure-sensitive adhesive sheet includes a base material layer, the adhesiveness (anchoring force) between the base material layer and the pressure-sensitive adhesive layer can be enhanced. That is, when the blending amount of the hydroxyl group-containing polyolefin is in the above range, an adhesive sheet with a small amount of adhesive residue can be obtained.

The blending amount of the cross-linking agent a is preferably 0.5 parts by weight or more, more preferably 1 part by weight, based on 100 parts by weight of the total of the base polymer (rubber), the hydroxyl group-containing polyolefin and the cross-linking agent a. It is 0.0 parts by weight or more. Within such a range, a highly cohesive pressure-sensitive adhesive layer can be formed. Further, when the pressure-sensitive adhesive sheet includes a base material layer, the adhesiveness (anchoring force) between the base material layer and the pressure-sensitive adhesive layer can be enhanced. That is, if the blending amount of the cross-linking agent a is in the above range, an adhesive sheet with a small amount of adhesive residue can be obtained.

As the hydroxyl group-containing polyolefin, a resin having excellent compatibility with the synthetic rubber is preferably used. Examples of the hydroxyl group-containing polyolefin include polyethylene-based polyols, polypropylene-based polyols, polybutadiene polyols, hydrogenated polybutadiene polyols, polyisoprene polyols, hydrogenated polyisoprene polyols, and the like. Of these, hydrogenated polyisoprene polyols, polyisoprene polyols, and polybutadiene polyols are preferable from the viewpoint of compatibility with the synthetic rubber.

The number average molecular weight (Mn) of the hydroxyl group-containing polyolefin is preferably 500 to 500,000, more preferably 1,000 to 200,000, and further preferably 1,200 to 150,000. The number average molecular weight can be measured according to ASTM D2503.

The hydroxyl value (mgKOH / g) of the hydroxyl group-containing polyolefin is preferably 5 to 95, more preferably 10 to 80. The hydroxyl value can be measured according to JIS K1557: 1970.

(Silicone adhesive)
As the silicone-based pressure-sensitive adhesive, any suitable pressure-sensitive adhesive can be used as long as the effects of the present invention can be obtained. As the silicone-based pressure-sensitive adhesive, for example, a silicone-based pressure-sensitive adhesive containing a silicone rubber containing an organopolysiloxane or a silicone resin as a base polymer is preferably used. As the base polymer constituting the silicone-based pressure-sensitive adhesive, a base polymer obtained by cross-linking the above-mentioned silicone rubber or silicone resin may be used. In addition, in this specification, "silicone rubber" means a polymer (for example, viscosity 1000Pa · s) in which diorganosiloxane (D unit) as a main component is linearly connected, and is "silicone resin". Means a polymer composed of triorganosylhemioxane (M unit) and silicate (Q unit) as main components ("Material design and functionalization of adhesive (film / tape)", Technical Information Association, published on September 30, 2009).

Examples of the silicone rubber include organopolysiloxane containing dimethylsiloxane as a constituent unit. A functional group (for example, a vinyl group) may be introduced into the organopolysiloxane, if necessary. The weight average molecular weight of the organopolysiloxane is preferably 100,000 to 1,000,000, more preferably 150,000 to 500,000. The weight average molecular weight can be measured by GPC (solvent: THF).

Examples of the silicone resin include an organopolysiloxane containing at least one structural unit selected from R ₃ SiO _1/2 structural unit, SiO ₂ structural unit, RSiO _3/2 structural unit and R ₂ SiO structural unit. (R is a monovalent hydrocarbon group or hydroxyl group).

The above silicone rubber and silicone resin can be used in combination. The weight ratio (rubber: resin) of the silicone rubber to the silicone resin in the silicone adhesive is preferably 100: 0 to 100: 220, more preferably 100: 0 to 100: 180, and further preferably 100: It is 10 to 100: 100. The silicone rubber and the silicone resin may be contained in the silicone-based pressure-sensitive adhesive as a mere mixture, or may be contained in the silicone-based pressure-sensitive adhesive in the form of a partial condensation of the silicone rubber and the silicone resin. The rubber: resin ratio can also be determined from the ratio of the Q unit (resin) and the D unit (rubber) obtained by measuring the composition of the silicone pressure-sensitive adhesive by ²⁹ Si-NMR.

The silicone-based pressure-sensitive adhesive may contain any suitable additive, if desired. Examples of the additive include a cross-linking agent, a vulcanizing agent, a tackifier, a plasticizer, a pigment, a dye, a filler, an antiaging agent, a conductive material, an antistatic agent, an ultraviolet absorber, a light stabilizer, and peeling adjustment. Examples thereof include agents, softeners, surfactants, flame retardants, antioxidants and the like.

Preferably, the silicone-based pressure-sensitive adhesive contains a cross-linking agent. Examples of the cross-linking agent include a siloxane-based cross-linking agent and a peroxide-based cross-linking agent. As the peroxide-based cross-linking agent, any suitable cross-linking agent can be used. Examples of the peroxide-based cross-linking agent include benzoyl peroxide, t-butylperoxybenzoate, and dicumyl peroxide. Examples of the siloxane-based cross-linking agent include polyorganohydrogensiloxane. The polyorganohydrogensiloxane preferably has two or more hydrogen atoms bonded to silicon atoms. Further, the polyorganohydrogensiloxane preferably has an alkyl group, a phenyl group, or an alkyl halide group as a functional group bonded to a silicon atom.

(Active energy ray-curable adhesive)
As the pressure-sensitive adhesive, an active energy ray-curable pressure-sensitive adhesive that can be cured (increased elastic modulus) by irradiation with active energy rays may be used. If an active energy ray-curable adhesive is used, a pressure-sensitive adhesive sheet that has low elasticity, high flexibility, and excellent handleability at the time of sticking, and can reduce the adhesive strength by irradiating with active energy rays in situations where peeling is required. Obtainable. Examples of the active energy ray include gamma ray, ultraviolet ray, visible ray, infrared ray (heat ray), radio wave, alpha ray, beta ray, electron beam, plasma flow, ionization ray, particle beam and the like. In addition, in this specification, the term "adhesive layer" means a pressure-sensitive adhesive layer before the pressure-sensitive adhesive is cured and the adhesive strength is lowered.

Examples of the resin material constituting the active energy ray-curable pressure-sensitive adhesive include an ultraviolet curing system (written by Kiyomi Kato, published by the General Technology Center, (1989)), a photocuring technology (edited by the Technical Information Association (2000)), and the like. Examples thereof include resin materials described in JP-A-2003-292916, Japanese Patent No. 4151850 and the like. More specifically, a resin material (R1) containing a polymer serving as a base material and an active energy ray-reactive compound (monomer or oligomer), a resin material containing an active energy ray-reactive polymer (R2), and the like can be mentioned.

Examples of the polymer serving as the base material include natural rubber, polyisobutylene rubber, styrene / butadiene rubber, styrene / isoprene / styrene block copolymer rubber, recycled rubber, butyl rubber, polyisobutylene rubber, nitrile rubber (NBR) and the like. Examples include rubber-based polymers; silicone-based polymers; acrylic-based polymers. These polymers may be used alone or in combination of two or more. As the polymer serving as the base material, preferably, the polymer exemplified as the base polymer of the acrylic pressure-sensitive adhesive, the rubber-based pressure-sensitive adhesive or the silicone-based pressure-sensitive adhesive can be preferably used from the viewpoint of compatibility with the sealing material.

Examples of the active energy ray-reactive compound include a photoreactive monomer or oligomer having a functional group having a carbon-carbon multiple bond such as an acryloyl group, a methacryloyl group, a vinyl group, an allyl group, and an acetylene group. Specific examples of the photoreactive monomer or oligomer include trimethylolpropane tri (meth) acrylate, tetramethylolmethanetetra (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, and dipenta. Elythritol monohydroxypenta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, polyethylene glycol di (meth) acrylate, etc. (Meta) acryloyl group-containing compound; 2 to pentamer of the (meth) acryloyl group-containing compound; and the like.

Further, as the active energy ray-reactive compound, a monomer such as epoxidized butadiene, glycidyl methacrylate, acrylamide, vinyl siloxane; or an oligomer composed of the monomer may be used. The resin material (R1) containing these compounds can be cured by high energy rays such as ultraviolet rays and electron beams.

Further, as the active energy ray-reactive compound, a mixture of an organic salt such as an onium salt and a compound having a plurality of heterocycles in the molecule may be used. In the mixture, the organic salt is cleaved by irradiation with active energy rays (for example, ultraviolet rays and electron beams) to generate ions, which act as a starting species to cause a ring-opening reaction of a heterocycle to form a three-dimensional network structure. Can be done. Examples of the organic salts include iodonium salt, phosphonium salt, antimonium salt, sulfonium salt, borate salt and the like. Examples of the heterocycle in the compound having a plurality of heterocycles in the molecule include oxylane, oxetane, oxolane, thiirane, and aziridine.

In the resin material (R1) containing the polymer serving as the base material and the active energy ray-reactive compound, the content ratio of the active energy ray-reactive compound is preferably 0. It is 1 part by weight to 500 parts by weight, more preferably 1 part by weight to 300 parts by weight, and further preferably 10 parts by weight to 200 parts by weight. Within such a range, a pressure-sensitive adhesive layer having a low affinity with the sealing material can be formed.

The resin material (R1) containing the polymer serving as a base material and the active energy ray-reactive compound may contain any suitable additive, if necessary. Examples of the additive include an active energy ray polymerization initiator, an active energy ray polymerization accelerator, a cross-linking agent, a plasticizer, a vulcanizing agent and the like. As the active energy ray polymerization initiator, any suitable initiator can be used depending on the type of active energy ray used. The active energy ray polymerization initiator may be used alone or in combination of two or more. In the resin material (R1) containing the polymer as the base material and the active energy ray-reactive compound, the content ratio of the active energy ray polymerization initiator is preferably 0.1 with respect to 100 parts by weight of the polymer as the base material. It is 10 parts by weight, more preferably 1 part to 5 parts by weight.

Examples of the active energy ray-reactive polymer include polymers having a functional group having a carbon-carbon multiple bond such as an acryloyl group, a methacryloyl group, a vinyl group, an allyl group, and an acetylene group. Specific examples of the polymer having an active energy ray-reactive functional group include a polymer composed of a polyfunctional (meth) acrylate. The polymer composed of the polyfunctional (meth) acrylate preferably has an alkyl ester having 4 or more carbon atoms, more preferably has an alkyl ester having 6 or more carbon atoms, and an alkyl having 8 or more carbon atoms. It is more preferable to have an ester, particularly preferably to have an alkyl ester having 8 to 20 carbon atoms, and most preferably to have an alkyl ester having 8 to 18 carbon atoms. A polymer having a long side chain can be used to form an adhesive layer having a low affinity for the encapsulating material. In the polymer, the content ratio of the structural unit having an alkyl ester having 4 or more carbon atoms as a side chain is preferably 30% by weight or more, more preferably 50% by weight, based on all the structural units constituting the polymer. % Or more, more preferably 70% by weight to 100% by weight, and particularly preferably 80% by weight to 100% by weight. Within such a range, a pressure-sensitive adhesive layer having a low affinity with the sealing material can be formed.

The resin material (R2) containing the active energy ray-reactive polymer may further contain the active energy ray-reactive compound (monomer or oligomer). In addition, the resin material (R2) containing the active energy ray-reactive polymer may contain any suitable additive, if necessary. Specific examples of the additive are the same as those of the additive that can be contained in the resin material (R1) containing the polymer as the base material and the active energy ray-reactive compound. In the resin material (R2) containing the active energy ray-reactive polymer, the content ratio of the active energy ray polymerization initiator is preferably 0.1 part by weight to 10 parts by weight with respect to 100 parts by weight of the active energy ray-reactive polymer. It is more preferably 1 part by weight to 5 parts by weight.

<Thermal expansion microsphere>
In one embodiment, the pressure-sensitive adhesive layer further comprises thermally expandable microspheres. When the pressure-sensitive adhesive sheet including the pressure-sensitive adhesive layer containing the heat-expandable microspheres is heated, the heat-expandable microspheres expand or fire to cause unevenness on the adhesive surface, and as a result, the adhesive strength is reduced or disappears. To do. Such an adhesive sheet can be easily peeled off by heating.

As the heat-expandable microsphere, any suitable heat-expandable microsphere can be used as long as it is a microsphere that can be expanded or foamed by heating. As the heat-expandable microsphere, for example, a microsphere in which a substance that easily expands by heating is contained in an elastic shell can be used. Such heat-expandable microspheres can be produced by any suitable method, for example, a coacervation method, an interfacial polymerization method, or the like.

Examples of substances that easily expand by heating include propane, propylene, butene, normal butane, isopentane, isopentane, neopentane, normal pentane, normal hexane, isohexane, heptane, octane, petroleum ether, methane halide, and tetraalkylsilane. Low boiling point liquids such as; azodicarboxylic amides that are gasified by thermal decomposition; and the like.

Examples of the substances constituting the shell include nitrile monomers such as acrylonitrile, methacrylonitrile, α-chloroacrylonitrile, α-ethoxyacrylonitrile, and fumaronitrile; acrylic acid, methacrylic acid, itaconic acid, maleic acid, and fumaric acid. Carboxylic acid monomers such as citraconic acid; vinylidene chloride; vinyl acetate; methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, (Meta) acrylic acid esters such as isobornyl (meth) acrylate, cyclohexyl (meth) acrylate, benzyl (meth) acrylate, β-carboxyethyl acrylate; styrene monomers such as styrene, α-methylstyrene, chlorostyrene; acrylamide, substituted acrylamide , Acrylate monomers such as methacrylicamide and substituted methacrylicamide; and the like. The polymer composed of these monomers may be a homopolymer or a copolymer. Examples of the copolymer include vinylidene chloride-methyl methacrylate-acrylonitrile copolymer, methyl methacrylate-acrylonitrile-methacrylonitrile copolymer, methyl methacrylate-acrylonitrile copolymer, and acrylonitrile-methacrylonitrile-itaconic acid. Examples include copolymers.

An inorganic foaming agent or an organic foaming agent may be used as the heat-expandable microspheres. Examples of the inorganic foaming agent include ammonium carbonate, ammonium hydrogencarbonate, sodium hydrogencarbonate, ammonium nitrite, sodium boron hydroxide, and various azides. Examples of the organic foaming agent include salt fluoride alkane compounds such as trichloromonofluoromethane and dichloromonofluoromethane; and azo compounds such as azobisisobutyronitrile, azodicarboxylicamide and barium azodicarboxylate. Hydrazide compounds such as paratoluenesulfonyl hydrazide, diphenylsulfone-3,3'-disulfonylhydrazide, 4,4'-oxybis (benzenesulfonylhydrazide), allylbis (sulfonylhydrazide); p-toluylenesulfonyl semicarbazide, 4, Semicarbazide compounds such as 4'-oxybis (benzenesulfonyl semicarbazide); triazole compounds such as 5-morpholyl-1,2,3,4-thiatriazole; N, N'-dinitrosopentamethylenetetramine, N, N' Examples thereof include N-nitroso compounds such as −dimethyl-N, N ′ -dinitrosoterephthalamide; and the like.

Commercially available products may be used as the heat-expandable microspheres. As a specific example of commercially available heat-expandable microspheres, the trade name "Matsumoto Microsphere" manufactured by Matsumoto Yushi Pharmaceutical Co., Ltd. (grades: F-30, F-30D, F-36D, F-36LV, F-50) , F-50D, F-65, F-65D, FN-100SS, FN-100SSD, FN-180SS, FN-180SD, F-190D, F-260D, F-2800D), trade name "Filite Japan" "Expansel" (grades: 053-40, 031-40, 920-40, 909-80, 930-120), "Dieform" manufactured by Kureha Chemical Industry Co., Ltd. (grades: H750, H850, H1100, S2320D, S2640D, M330, M430, M520), "Advancel" manufactured by Sekisui Chemical Co., Ltd. (grades: EML101, EMH204, EHM301, EHM302, EHM303, EM304, EHM401, EM403, EM501) and the like.

The particle size of the heat-expandable microspheres before heating is preferably 0.5 μm to 80 μm, more preferably 5 μm to 45 μm, still more preferably 10 μm to 20 μm, and particularly preferably 10 μm to 15 μm. .. Therefore, the particle size of the heat-expandable microspheres before heating is preferably 6 μm to 45 μm, more preferably 15 μm to 35 μm in terms of average particle size. The above particle size and average particle size are values obtained by the particle size distribution measurement method in the laser scattering method.

The heat-expandable microspheres preferably have an appropriate strength that does not burst until the coefficient of thermal expansion is preferably 5 times or more, more preferably 7 times or more, and further preferably 10 times or more. When such a heat-expandable microsphere is used, the adhesive strength can be efficiently reduced by the heat treatment.

The content ratio of the heat-expandable microspheres in the pressure-sensitive adhesive layer can be appropriately set according to the desired decrease in adhesive strength and the like. The content of the heat-expandable microspheres is, for example, 1 part by weight to 150 parts by weight, preferably 10 parts by weight to 130 parts by weight, more preferably 100 parts by weight, based on 100 parts by weight of the base polymer forming the pressure-sensitive adhesive layer. Is 25 to 100 parts by weight.

When the pressure-sensitive adhesive layer contains heat-expandable microspheres, the arithmetic surface roughness Ra of the pressure-sensitive adhesive layer before the heat-expandable microspheres expand (that is, before heating) is preferably 500 nm or less, more preferably. Is 400 nm or less, more preferably 300 nm or less. Within such a range, an adhesive sheet having excellent adhesion to the adherend can be obtained. The pressure-sensitive adhesive layer having excellent surface smoothness can be obtained by, for example, setting the thickness of the pressure-sensitive adhesive layer within the above range, or by applying the pressure-sensitive adhesive layer to a separator and transferring the pressure-sensitive adhesive layer when another pressure-sensitive adhesive layer is provided. Obtainable. As described in Section A above, when the pressure-sensitive adhesive sheet of the present invention further includes another pressure-sensitive adhesive layer, the other pressure-sensitive adhesive layer may contain thermally expandable microspheres. Even when another pressure-sensitive adhesive layer contains heat-expandable microspheres, the arithmetic surface roughness Ra of the pressure-sensitive adhesive layer is preferably in the above range.

When the pressure-sensitive adhesive layer contains thermally expandable microspheres, the pressure-sensitive adhesive layer is composed of a base polymer having a dynamic storage elastic modulus in the range of 5 kPa to 1 MPa (more preferably 10 kPa to 0.8 MPa) at 80 ° C. It is preferable to include a pressure-sensitive adhesive. With such an adhesive layer, it is possible to form an adhesive sheet which has an appropriate adhesiveness before heating and whose adhesive strength tends to decrease by heating. The dynamic storage elastic modulus can be measured by using a dynamic viscoelasticity measuring device (for example, trade name "ARES" manufactured by Leometrics) under measurement conditions of a frequency of 1 Hz and a heating rate of 10 ° C./min. ..

C. Base material layer In one embodiment, the pressure-sensitive adhesive sheet of the present invention comprises a pressure-sensitive adhesive layer and a base material layer. FIG. 2A is a schematic cross-sectional view of the pressure-sensitive adhesive sheet according to one embodiment of the present invention. The pressure-sensitive adhesive sheet 100 includes a pressure-sensitive adhesive layer 10 and a base material layer 30 arranged on one side of the pressure-sensitive adhesive layer 10. FIG. 2B is a schematic cross-sectional view of the pressure-sensitive adhesive sheet according to another embodiment of the present invention. The pressure-sensitive adhesive sheet 200 includes a pressure-sensitive adhesive layer 10 and a base material layer 30, and the pressure-sensitive adhesive layers 10 are arranged on both sides of the base material layer 30. The two pressure-sensitive adhesive layers may be pressure-sensitive adhesive layers having the same structure or different pressure-sensitive adhesive layers. The pressure-sensitive adhesive layer may be provided on one side of the base material layer, and another pressure-sensitive adhesive layer may be provided on the other side.

When the pressure-sensitive adhesive sheet of the present invention includes a base material layer, the anchoring force between the base material layer and the pressure-sensitive adhesive layer is preferably 6.0 N / 19 mm or more, and more preferably 15 N / 19 mm or more.

The anchoring force can be measured as follows. The anchoring force is (i) the surface of the pressure-sensitive adhesive sheet having a width of 20 mm and a length of 150 mm opposite to the pressure-sensitive adhesive layer (for example, in the case of a pressure-sensitive adhesive sheet having a base material layer / pressure-sensitive adhesive layer structure, the outer surface of the base material layer). ), A SUS plate is attached to the entire surface of the adhesive sheet via a predetermined double-sided tape, and (ii) an adhesive containing a polyester resin having a size of 19 mm in width and 150 mm in length on the outer surface of the adhesive layer of the adhesive sheet. Evaluation sheet (sheet having peeling adhesive strength of 10N / 20mm to 20N / 20mm with respect to polyethylene terephthalate, for example, product name "No. 315 tape" manufactured by Nitto Denko Co., Ltd.) is attached and evaluated. A sample for use is prepared, and (iii) the peeling force between the base material layer and the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet is measured by a tensile test. The above (i) to (iii) are performed under an ambient temperature of 23 ° C. The conditions of the tensile test when measuring the peeling force are a peeling speed of 50 mm / min and a peeling angle of 180 °.

As described above, the pressure-sensitive adhesive sheet having a high anchoring force between the base material layer and the pressure-sensitive adhesive layer is essentially a pressure-sensitive adhesive sheet in which adhesive does not easily remain, and such a pressure-sensitive adhesive sheet is said to have a remarkable effect of the present invention. Become. When evaluated by the above method, it is more preferable that the pressure-sensitive adhesive sheet does not peel off at the interface between the base material layer and the pressure-sensitive adhesive layer, and peels off between the SUS plate and the base material layer, for example. A pressure-sensitive adhesive sheet having a high anchoring force can be obtained, for example, by using the rubber-based pressure-sensitive adhesive (Rub1) as the pressure-sensitive adhesive, adding an isocyanate-based cross-linking agent to the pressure-sensitive adhesive, and the like.

Examples of the base material layer include resin sheets, non-woven fabrics, paper, metal foils, woven fabrics, rubber sheets, foam sheets, and laminates thereof (particularly, laminates containing resin sheets). Examples of the resin constituting the resin sheet include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate (PBT), polyethylene (PE), polypropylene (PP), ethylene-propylene copolymer, and ethylene-. Vinyl acetate copolymer (EVA), polyamide (nylon), total aromatic polyamide (aramid), polyimide (PI), polyvinyl chloride (PVC), polyphenylene sulfide (PPS), fluororesin, polyetheretherketone (PEEK) ) Etc. can be mentioned. Examples of the non-woven fabric include non-woven fabrics made of natural fibers having heat resistance such as non-woven fabrics containing Manila hemp; synthetic resin non-woven fabrics such as polypropylene resin non-woven fabrics, polyethylene resin non-woven fabrics and ester resin non-woven fabrics. Examples of the metal foil include copper foil, stainless steel foil, aluminum foil and the like. Examples of paper include Japanese paper and kraft paper.

The thickness of the base material layer can be set to an arbitrary appropriate thickness depending on the desired strength or flexibility, the purpose of use, and the like. The thickness of the base material layer is preferably 1000 μm or less, more preferably 1 μm to 1000 μm, further preferably 1 μm to 500 μm, particularly preferably 3 μm to 300 μm, and most preferably 5 μm to 250 μm.

The base material layer may be surface-treated. Examples of the surface treatment include corona treatment, chromic acid treatment, ozone exposure, flame exposure, high-voltage impact exposure, ionizing radiation treatment, coating treatment with an undercoat agent, and the like.

Examples of the organic coating material include the materials described in Plastic Hard Coat Material II (CMC Publishing, (2004)). Urethane-based polymers are preferably used, more preferably polyacrylic urethane, polyester urethane, or precursors thereof. This is because it is easy to apply and apply to the base material, and various types can be industrially selected and obtained at low cost. The urethane-based polymer is, for example, a polymer composed of a reaction mixture of an isocyanato monomer and an alcoholic hydroxyl group-containing monomer (for example, a hydroxyl group-containing acrylic compound or a hydroxyl group-containing ester compound). The organic coating material may contain a chain extender such as polyamine, an antiaging agent, an oxidation stabilizer and the like as arbitrary additives. The thickness of the organic coating layer is not particularly limited, but for example, about 0.1 μm to 10 μm is suitable, about 0.1 μm to 5 μm is preferable, and about 0.5 μm to 5 μm is more preferable.

D. Elastic layer The pressure-sensitive adhesive sheet of the present invention may further include an elastic layer. FIG. 3 is a schematic cross-sectional view of the pressure-sensitive adhesive sheet according to one embodiment of the present invention. The pressure-sensitive adhesive sheet 300 further includes an elastic layer 40. The elastic layer 40 can be preferably arranged when the pressure-sensitive adhesive layer 10 contains the heat-expandable microspheres. Further, when the pressure-sensitive adhesive sheet 300 includes the base material layer 30, the elastic layer 40 may be arranged between the pressure-sensitive adhesive layer 10 and the base material layer 30 as shown in the illustrated example, and the base material layer may be adhered. It may be provided on the side opposite to the agent layer. Two or more elastic layers 40 may be provided. Note that FIG. 3 shows an example in which one elastic layer 40 is provided, and the elastic layer 40 is arranged between the pressure-sensitive adhesive layer 10 and the base material layer 30. By providing the elastic layer 40, the followability to the adherend is improved. Further, when the pressure-sensitive adhesive sheet provided with the elastic layer 40 is heated at the time of peeling, the deformation (expansion) of the pressure-sensitive adhesive layer in the surface direction is restrained, and the deformation in the thickness direction is prioritized. As a result, the peelability is improved.

The elastic layer contains a base polymer, and as the base polymer, a polymer exemplified as the base polymer constituting the pressure-sensitive adhesive layer can be used. Further, the elastic layer may contain natural rubber, synthetic rubber, synthetic resin and the like. Examples of the synthetic rubber and synthetic resin include nitrile-based, diene-based, and acrylic-based synthetic rubber; polyolefin-based, polyester-based thermoplastic elastomers; ethylene-vinyl acetate copolymer; polyurethane; polybutadiene; and soft polyvinyl chloride. Can be mentioned. The base polymer constituting the elastic layer may be the same as or different from the base polymer forming the pressure-sensitive adhesive layer. The elastic layer may be a foamed film formed from the base polymer. The foamed film can be obtained by any suitable method. The elastic layer and the pressure-sensitive adhesive layer can be distinguished by the difference in the base polymer and / or the presence or absence of the heat-expandable microspheres (the elastic layer does not contain the heat-expandable microspheres).

The elastic layer may optionally contain any suitable additive. Examples of the additive include a cross-linking agent, a vulcanizing agent, a tackifier, a plasticizer, a softener, a filler, an anti-aging agent and the like. When a hard resin such as polyvinyl chloride is used as the base polymer, it is preferable to use a plasticizer and / or a softener in combination to form an elastic layer having desired elasticity.

The thickness of the elastic layer is preferably 3 μm to 200 μm, more preferably 5 μm to 100 μm. Within such a range, the above-mentioned function of the elastic layer can be fully exerted.

The tensile elastic modulus of the elastic layer at 25 ° C. is preferably less than 100 MPa, more preferably 0.1 MPa to 50 MPa, and further preferably 0.1 MPa to 10 MPa. Within such a range, the above-mentioned function of the elastic layer can be fully exerted.

E. Separator The pressure-sensitive adhesive sheet of the present invention may further include a separator, if necessary. At least one surface of the separator is a peeling surface, and the separator may be provided to protect the pressure-sensitive adhesive layer. The separator can be constructed from any suitable material.

F. Method for Producing Adhesive Sheet The adhesive sheet of the present invention can be produced by any suitable method. The pressure-sensitive adhesive sheet of the present invention is, for example, a method of directly coating a composition containing an adhesive directly on a base material layer (in the case of obtaining a pressure-sensitive adhesive sheet containing no base material layer, any suitable base material), or any method. Examples thereof include a method of transferring a coating layer formed by coating a composition containing an adhesive on an appropriate substrate of the above to a substrate layer. The composition containing the pressure-sensitive adhesive may contain any suitable solvent.

When forming a pressure-sensitive adhesive layer containing heat-expandable microspheres, a composition containing the heat-expandable microspheres, a pressure-sensitive adhesive, and an arbitrary suitable solvent is applied to the base material layer to form the pressure-sensitive adhesive layer. can do. Alternatively, after sprinkling the heat-expandable microspheres on the pressure-sensitive adhesive coating layer, the heat-expandable microspheres are embedded in the pressure-sensitive adhesive using a laminator or the like to form a pressure-sensitive adhesive layer containing the heat-expandable microspheres. It may be formed.

When the pressure-sensitive adhesive layer has the above-mentioned elastic layer, the elastic layer can be formed, for example, by applying a composition for forming the elastic layer on the base material layer or the pressure-sensitive adhesive layer.

As the coating method of the pressure-sensitive adhesive and each composition, any suitable coating method can be adopted. For example, it can be applied and then dried to form each layer. Examples of the coating method include a coating method using a multi-coater, a die coater, a gravure coater, an applicator, and the like. Examples of the drying method include natural drying and heat drying. The heating temperature for heat-drying can be set to any suitable temperature depending on the characteristics of the substance to be dried.

Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited to these Examples. The evaluation method in the examples is as follows. Further, in the examples, unless otherwise specified, "parts" and "%" are based on weight.

(1) Contact angle The pressure-sensitive adhesive sheet was placed on a slide glass with the pressure-sensitive adhesive layer facing up, and the contact angle of the surface of the pressure-sensitive adhesive layer with respect to 4-tershally butylphenylglycidyl ether was measured.
2 μl of 4-tertiary butylphenylglycidyl ether was added dropwise to the surface of the pressure-sensitive adhesive layer, and the contact angle after 5 seconds was measured (N = 5). The contact angle was measured using a contact angle meter (manufactured by Kyowa Interface Science, trade name "CX-A type") in an atmosphere of 23 ° C. and 50% RH.

(2) sp value The sp value of the polymer in the pressure-sensitive adhesive layer after forming the pressure-sensitive adhesive sheet is determined by the method of Fedors (Hideki Yamamoto, "Sp value basics / applications and calculation methods", Information Organization Publishing Co., Ltd., 2006. Calculated according to (published on April 3, 2014, pages 66-67). Specifically, the sp value is the evaporation energy Δe (cal) of each atom or atomic group forming the polymer at 25 ° C. and the molar volume ΔV (cm ³ ) of each atom or atomic group forming the polymer at 25 ° C. ) And calculated by the following formula.
Sp value = (ΣΔe / ΣΔv) ^1/2
When the polymer is a copolymer, the SP value is calculated as the SP value of each homopolymer of each structural unit constituting the copolymer, and each structural unit is added to each of these SP values. It is calculated by multiplying by the mole fraction of.
In the above case, in the analysis method of each structural unit (polymer composition analysis), only the pressure-sensitive adhesive layer is appropriately collected from the pressure-sensitive adhesive sheet and immersed in an organic solvent such as dimethylformamide (DMF), acetone, methanol or tetrahydrofuran (THF). The solvent-soluble moiety thus obtained can be recovered and obtained from gel permeation chromatography (GPC), nuclear magnetic resonance spectroscopy (NMR), infrared spectroscopy (IR), and mass spectrometry.

(3) Adhesive strength A double-sided adhesive tape (manufactured by Nitto Denko KK, product name "No. 531") is placed on the entire surface of the adhesive sheet (width 20 mm x length 140 mm) opposite to the adhesive layer. The SUS304 plate was attached using a 2 kg hand roller.
Next, a polyethylene terephthalate film (manufactured by Toray Industries, Inc., trade name "Lumirror S-10", thickness: 25 μm, width: 30 mm) was attached to the entire surface of the pressure-sensitive adhesive layer (temperature: 23 ° C., humidity: 65%). 2kg roller 1 round trip).
The evaluation sample obtained as described above was subjected to a tensile test. As the tensile tester, the trade name "Shimadzu Autograph AG-120kN" manufactured by Shimadzu Corporation was used. After setting the evaluation sample in the tensile tester, the sample was left at an ambient temperature of 23 ° C. for 30 minutes, and then the tensile test was started. The conditions of the tensile test were a peeling angle: 180 ° and a peeling speed (pulling speed): 300 mm / min. The load when the adhesive sheet was peeled off from the PET film was measured, and the maximum load at that time was taken as the adhesive force of the adhesive sheet.

(4) Anchoring force A double-sided adhesive tape (Nitto Denko KK, product name "No. 531") is used on the entire surface of the adhesive sheet (width 20 mm x length 140 mm) opposite to the adhesive layer. A SUS304 plate (width 40 mm × length 120 mm) was attached using a 2 kg hand roller.
Next, an evaluation sheet (Nitto Denko KK, trade name "No. 315 tape", width 19 mm x length 150 mm) was attached (temperature: 23 ° C., humidity: 65%, 2 kg roller 1 reciprocation).
The evaluation sample obtained as described above was subjected to a tensile test. As the tensile tester, the trade name "Shimadzu Autograph AG-120kN" manufactured by Shimadzu Corporation was used. The conditions of the tensile test were a peeling angle: 180 ° and a peeling speed (pulling speed): 50 mm / min. The load when the pressure-sensitive adhesive layer was to be peeled off from the base material layer of the pressure-sensitive adhesive sheet was measured by grasping the evaluation sheet, and the maximum load at that time was defined as the anchoring force between the base material layer and the pressure-sensitive adhesive layer. ..

(5) Tack value A double-sided adhesive tape (Nitto Denko Co., Ltd., trade name "No. 531") is used on the entire surface of the adhesive sheet (width 20 mm x length 50 mm) opposite to the adhesive layer. A slide glass (manufactured by Matsunami Glass Industry Co., Ltd., 26 mm × 76 mm) was attached using a 2 kg hand roller.
The probe tack value of the outer surface of the pressure-sensitive adhesive layer in the evaluation sample obtained as described above was measured using a probe tack measuring machine (manufactured by RHESCA, trade name "TACKINESS Model TAC-II"). The measurement conditions are probe processing speed (Immersion speed): 30 mm / min, test speed (test speed): 30 mm / min, adhesion load (Prerod): 100 gf, adhesion holding time (press time): 1 second, probe area (Probe). Area): 5 mmφ SUS.

(6) Holding power test Under an ambient temperature of 23 ° C, the entire outer surface of the adhesive layer of the adhesive sheet (width 10 mm x length 150 mm) was covered with a bakelite plate (manufactured by Futamura Chemical Co., Ltd., trade name "Taikolite FL-102", It was attached to the central portion (width 25 mm × length 125 mm × thickness 2 mm) using a 2 kg hand roller.
The evaluation sample obtained as described above is left to stand at an ambient temperature of 40 ° C. for 30 minutes for aging, and then a tape creep tester (manufactured by Imada Seisakusho Co., Ltd., model / model number "12-series weight type / 041". A load of 1.96 N was applied using ”), and the state was maintained and left for 2 hours.
The moving distance (deviation) of the adhesive sheet due to pressurization was measured with reference to the position on the Bakelite plate before pressurization. The shorter the moving distance, the higher the holding force.

(7) Surface Roughness The arithmetic surface roughness Ra of the surface of the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet was measured according to JIS B0601. An optical surface roughness meter (manufactured by Veeco Technology Group, trade name "Wyko NT9100") was used as the measuring machine.

(8) Stand-off suppression effect Naphthalene type bifunctional epoxy resin (manufactured by DIC, trade name "HP4032D", epoxy equivalent: 144) by 100 parts by weight and phenoxy resin (manufactured by Mitsui Chemicals, trade name "EP4250") by 40 weight 129 parts by weight of phenol resin (manufactured by Meiwa Kasei Co., Ltd., trade name "MEH-8000"), 1137 parts by weight of spherical silica (manufactured by Admatex, trade name "SO-25R"), and dye (Orient Chemical Industry Co., Ltd.) 14 parts by weight of a curing catalyst (manufactured by Shikoku Kasei Co., Ltd., trade name "2PHZ-PW") and 30 parts by weight of methyl ethyl ketone are mixed and mixed with 14 parts by weight of a resin solution A. (Solid content concentration: 23.6% by weight) was prepared.
A Si wafer (1 cm × 1 cm, thickness 500 μm) is placed on the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet, and the resin solution A is applied so as to cover and seal the Si wafer on the pressure-sensitive adhesive layer. (Coating size: 3 cm × 3 cm), the resin solution was heated at 170 ° C. for 10 minutes to be cured to form a structure composed of a Si wafer and a sealing resin on the adhesive layer of the adhesive sheet.
After cooling, the adhesive sheet was peeled off from the structure. For the adhesive sheet after peeling, the difference between the thickness of the adhesive layer in the portion not in contact with the Si wafer and the thickness of the adhesive layer in the portion in contact with the Si wafer was defined as the standoff amount.

(9) Adhesive Residue As described in (8) above, a structure composed of a Si wafer and a sealing resin was formed on the pressure-sensitive adhesive sheet, and after cooling, the pressure-sensitive adhesive sheet was peeled off from the structure. After peeling, the sticking surface of the above structure was observed with a microscope (manufactured by KEYENCE, trade name "VHX-100", magnification: 150 times) to confirm the presence or absence of the adhesive layer component still attached to the structure. .. In Table 1, the case where the number of deposits having a particle size of 100 μm (in the case of an amorphous shape, the length of the longest side is 100 μm) or more was less than 5, was evaluated as ◯, and the case of 5 or more was evaluated as ×.

[Example 1]
Acrylic copolymer as a base polymer (copolymer of 2 ethylhexyl acrylate and hydroxyethyl acrylate, 2 ethylhexyl acrylate constituent unit: hydroxyethyl acrylate constituent unit = 100: 5 (weight ratio)) 100 parts by weight and an isocyanate-based cross-linking agent ( A mixture of 1.5 parts by weight of the product name "Coronate L" manufactured by Nippon Polyurethane Co., Ltd., 10 parts by weight of a terpenphenol adhesive resin (manufactured by Yasuhara Chemical Co., Ltd., product name "YS Polystar S145") and 100 parts by weight of toluene is mixed. , A composition for forming an adhesive layer was prepared.
The composition for forming the pressure-sensitive adhesive layer is applied to one side of a polytetrafluoroethylene film (manufactured by Toray Industries, Inc., trade name "Lumilar S10", thickness 38 μm) as a base material layer, and the base material layer and the pressure-sensitive adhesive layer are applied. An adhesive sheet composed of (thickness 10 μm) was obtained.

[Example 2]
Acrylic copolymer as a base polymer (copolymer of 2 ethylhexyl acrylate, acrylic acid and trimethylolpropane acrylate, 2 ethylhexyl acrylate constituent unit: acrylate constituent unit: trimethylolpropane acrylate constituent unit = 100: 3: 0 .03 (weight ratio)) 100 parts by weight, epoxy-based cross-linking agent (manufactured by Mitsubishi Gas Chemicals, trade name "Tetrad C"), 0.5 parts by weight, and terpenphenol-based tackifier resin (manufactured by Yasuhara Chemical Co., Ltd., trade name) “YS Polystar S145”) 10 parts by weight and 100 parts by weight of toluene were mixed to prepare a composition for forming an adhesive layer.
The composition for forming the pressure-sensitive adhesive layer is applied to one side of a polytetrafluoroethylene film (manufactured by Toray Industries, Inc., trade name "Lumilar S10", thickness 38 μm) as a base material layer, and the base material layer and the pressure-sensitive adhesive layer are applied. An adhesive sheet composed of (thickness 10 μm) was obtained.

[Example 3]
Additive reaction type silicone adhesive (manufactured by Toray, trade name "Silicone rubber SD-4580L", silicone rubber: silicone resin = 60:40 (weight ratio)) 100 parts by weight and platinum catalyst (manufactured by Toray, product Name "SRX-212") 0.5 parts by weight and 100 parts by weight of toluene were mixed to prepare a composition for forming a pressure-sensitive adhesive layer.
The composition for forming the pressure-sensitive adhesive layer is applied to one side of a polyimide film (manufactured by Toray DuPont, trade name "Kapton 200H", thickness 50 μm) as a base material layer, and the base material layer and the pressure-sensitive adhesive layer (10 μm) are coated. ) And an adhesive sheet composed of.

[Example 4]
100 parts by weight of polyisobutylene rubber (manufactured by BASF Japan, trade name "Opanol B80"), 1.5 parts by weight of hydroxyl group-containing polyolefin (manufactured by Idemitsu Kosan Co., Ltd., trade name "Epol"), and isocyanate-based cross-linking agent (Japan) 4 parts by weight of Polyurethane Industry Co., Ltd., trade name "Coronate L") and 200 parts by weight of toluene were mixed to prepare a composition for forming an adhesive layer.
The pressure-sensitive adhesive forming composition is applied to one side of a polytetrafluoroethylene film (manufactured by Toray Industries, Inc., trade name "Lumilar S10", thickness 38 μm) as a base material layer, and the base material layer and the pressure-sensitive adhesive layer ( An adhesive sheet composed of (thickness 10 μm) was obtained.

[Example 5]
30 parts by weight of heat-expandable microspheres (manufactured by Matsumoto Yushi Pharmaceutical Co., Ltd., trade name "Matsumoto Microsphere F-50") were further added to the composition for forming the pressure-sensitive adhesive layer to make the thickness of the pressure-sensitive adhesive layer 40 μm. An adhesive sheet was obtained in the same manner as in Example 1 except for the above.

[Example 6]
30 parts by weight of heat-expandable microspheres (manufactured by Matsumoto Yushi Pharmaceutical Co., Ltd., trade name "Matsumoto Microsphere F-50") were further added to the composition for forming the pressure-sensitive adhesive layer to make the thickness of the pressure-sensitive adhesive layer 40 μm. An adhesive sheet was obtained in the same manner as in Example 2 except for the above.

[Example 7]
30 parts by weight of heat-expandable microspheres (manufactured by Matsumoto Yushi Pharmaceutical Co., Ltd., trade name "Matsumoto Microsphere F-50") were further added to the composition for forming the pressure-sensitive adhesive layer to make the thickness of the pressure-sensitive adhesive layer 40 μm. An adhesive sheet was obtained in the same manner as in Example 3 except for the above.

[Example 8]
30 parts by weight of heat-expandable microspheres (manufactured by Matsumoto Yushi Pharmaceutical Co., Ltd., trade name "Matsumoto Microsphere F-50") were further added to the composition for forming the pressure-sensitive adhesive layer to make the thickness of the pressure-sensitive adhesive layer 40 μm. An adhesive sheet was obtained in the same manner as in Example 4 except for the above.

[Example 9]
A composition for forming an adhesive layer was prepared in the same manner as in Example 1.
Acrylic copolymer (copolymer of ethyl acrylate, diethylhexyl acrylate and hydroxyethyl acrylate, ethyl acrylate constituent unit: 2-ethylhexyl acrylate constituent unit: hydroxyethyl acrylate constituent unit: 70:30: 5: 6 (weight ratio) ) 100 parts by weight, 2 parts by weight of an isocyanate-based cross-linking agent (manufactured by Nippon Polyurethane Industry Co., Ltd., trade name "Coronate L") and 100 parts by weight of toluene were mixed to prepare an elastic layer forming composition.
Acrylic copolymer (copolymer of ethyl acrylate, diethylhexyl acrylate and hydroxyethyl acrylate, ethyl acrylate constituent unit: 2-ethylhexyl acrylate constituent unit: hydroxyethyl acrylate constituent unit: 70:30: 5: 6 (weight ratio) ) 100 parts by weight, 2 parts by weight of isocyanate-based cross-linking agent (manufactured by Nippon Polyurethane Industry Co., Ltd., trade name "Coronate L"), and rosinphenol-based adhesive-imparting resin (manufactured by Sumitomo Bakelite Co., Ltd. ”) 15 parts by weight, 35 parts by weight of heat-expandable microspheres (manufactured by Matsumoto Yushi Pharmaceutical Co., Ltd., trade name“ Matsumoto Microsphere F-50 ”) and 100 parts by weight of toluene are mixed to form another adhesive layer. Composition was prepared.
The composition for forming the pressure-sensitive adhesive layer is applied to one side of a PET film (manufactured by Toray Industries, Inc., trade name "Lumilar S10", thickness 38 μm) as a base material layer, and the pressure-sensitive adhesive layer (thickness) is applied on the base material layer. 10 μm) was formed. Further, an elastic layer forming composition was applied to the other surface of the PET film to form an elastic layer (thickness 10 μm) on the base material layer.
Separately, another pressure-sensitive adhesive layer-forming composition was applied onto another PET film to form another pressure-sensitive adhesive layer (thickness 35 μm). The other pressure-sensitive adhesive layer was transferred onto the elastic layer to obtain a pressure-sensitive adhesive sheet composed of a pressure-sensitive adhesive layer / base material layer / elastic layer / another pressure-sensitive adhesive layer.

[Example 10]
A pressure-sensitive adhesive sheet was obtained in the same manner as in Example 9 except that the pressure-sensitive adhesive layer-forming composition obtained in Example 2 was used as the pressure-sensitive adhesive layer-forming composition.

[Example 11]
A pressure-sensitive adhesive sheet was obtained in the same manner as in Example 9 except that the pressure-sensitive adhesive layer-forming composition obtained in Example 3 was used as the pressure-sensitive adhesive layer-forming composition.

[Example 12]
A pressure-sensitive adhesive sheet was obtained in the same manner as in Example 9 except that the pressure-sensitive adhesive layer-forming composition obtained in Example 4 was used as the pressure-sensitive adhesive layer-forming composition.

[Comparative Example 1]
Acrylic copolymer (copolymer of methyl acrylate, diethylhexyl acrylate and acrylic acid, methyl acrylate constituent unit: 2-ethylhexyl acrylate constituent unit: acrylic acid constituent unit = 15: 85: 8 (weight ratio)) 100 parts by weight , 3 parts by weight of epoxy-based cross-linking agent (manufactured by Mitsubishi Gas Chemical Co., Ltd., trade name "Tetrad C"), 10 parts by weight of terpenphenol-based tackifier resin (manufactured by Yasuhara Chemical Co., Ltd., trade name "YS Polystar S145"), and toluene A composition for forming an adhesive layer was prepared by mixing with 100 parts by weight.
The composition for forming the pressure-sensitive adhesive layer is applied to one side of a polytetrafluoroethylene film (manufactured by Toray Industries, Inc., trade name "Lumilar S10", thickness 38 μm) as a base material layer, and the base material layer and the pressure-sensitive adhesive layer are applied. An adhesive sheet composed of (thickness 10 μm) was obtained.

As is clear from Table 1, the pressure-sensitive adhesive sheet of the present invention includes a pressure-sensitive adhesive layer having a contact angle of 15 ° or more with respect to 4-tertiary butylphenylglycidyl ether, that is, a pressure-sensitive adhesive having a low affinity for a sealing resin. By providing the agent layer, it is possible to obtain an adhesive sheet in which standoffs are less likely to occur and adhesive residue is less likely to occur.

10 Adhesive layer 30 Base material layer 40 Elastic layer 100, 200, 300 Adhesive sheet

Claims (12)

A pressure-sensitive adhesive sheet comprising a base material layer, a pressure-sensitive adhesive layer arranged on one surface of the base material layer, and a pressure-sensitive adhesive layer or another pressure-sensitive adhesive layer arranged on the other side of the base material layer. There,
The pressure-sensitive adhesive layer contains an acrylic pressure-sensitive adhesive and heat-expandable microspheres .
The acrylic pressure-sensitive adhesive contains, as a base polymer, an acrylic polymer having an alkyl ester having 4 or more carbon atoms in the side chain.
In the acrylic polymer, the content ratio of the structural unit having an alkyl ester having 4 or more carbon atoms in the side chain is 30% by weight or more with respect to all the structural units constituting the acrylic polymer.
The contact angle of the surface of the pressure-sensitive adhesive layer with respect to 4-tertiary butylphenylglycidyl ether is 15 ° or more.
The adhesive strength of the adhesive sheet to polyethylene terephthalate at 23 ° C. is 0.5 N / 20 mm or more.
An adhesive sheet used as a temporary fixing material when a plurality of semiconductor chips are collectively sealed with a sealing resin in a wafer level package. The pressure-sensitive adhesive sheet according to claim 1, wherein the sp value of the material constituting the pressure-sensitive adhesive in the pressure-sensitive adhesive layer is 7 (cal / cm ³ ) ^1/2 to 10 (cal / cm ³ ) ^1/2 . The pressure-sensitive adhesive sheet according to claim 1 or 2, wherein the probe tack value of the pressure-sensitive adhesive layer is 50 N / 5 mmφ or more. The acrylic pressure-sensitive adhesive contains, as a base polymer, an acrylic polymer having an alkyl ester having 6 or more carbon atoms in a side chain.
In the acrylic polymer, the content ratio of the structural unit having an alkyl ester having 6 or more carbon atoms in the side chain is 50% by weight or more with respect to all the structural units constituting the acrylic polymer.
The adhesive sheet according to any one of claims 1 to 3. The pressure-sensitive adhesive sheet according to any one of claims 1 to 4, wherein the acrylic polymer contains a structural unit derived from a hydroxyl group-containing monomer. The pressure-sensitive adhesive sheet according to claim 5, wherein the content ratio of the structural unit derived from the hydroxyl group-containing monomer is 0.1% by weight to 20% by weight with respect to all the structural units constituting the acrylic polymer. The pressure-sensitive adhesive sheet according to claim 6 , wherein the arithmetic surface roughness Ra of the pressure-sensitive adhesive layer before heating the heat-expandable microspheres is 500 nm or less. When the entire outer surface of the pressure-sensitive adhesive layer was attached to a bakelite plate under an environmental temperature of 23 ° C., aged for 30 minutes at an environmental temperature of 40 ° C., and then held for 2 hours while applying a load of 1.96 N, the said. The adhesive sheet according to any one of claims 1 to 7 , wherein the deviation from the bakelite plate is 0.5 mm or less. The pressure-sensitive adhesive sheet according to any one of claims 1 to 8 , wherein the anchoring force between the base material layer and the pressure-sensitive adhesive layer is 6.0 N / 19 mm or more. The adhesive sheet according to any one of claims 1 to 9 , further comprising an elastic layer. The pressure-sensitive adhesive sheet according to claim 10 , wherein the elastic layer is arranged between the pressure-sensitive adhesive layer and the base material layer. The pressure-sensitive adhesive sheet according to claim 10 or 11 , wherein the elastic modulus of the elastic layer at 25 ° C. is less than 100 Mpa.

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