KR20210013260A - Pressure-Sensitive Adhesive Sheet - Google Patents

Abstract

The present invention provides a pressure-sensitive adhesive sheet that has adequate adhesion to a sealing resin and a semiconductor chip constituting a semiconductor package, can be easily peeled from the sealing resin and semiconductor chip, and can prevent residual adhesive during peeling. In the following, the pressure-sensitive adhesive sheet of the present invention is a pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer, the contact angle of the surface of the pressure-sensitive adhesive layer to 4-tert-butylphenylglycidyl ether is 15° or more, and the pressure-sensitive adhesive sheet is 23°C. The adhesion to polyethylene terephthalate in is 0.5 N/20 mm or more.

Description

Adhesive sheet {Pressure-Sensitive Adhesive Sheet}

The present invention relates to an adhesive sheet.

2. Description of the Related Art [0002] In recent years, when miniaturization of semiconductor devices is required, as a semiconductor packaging technology, CSP (Chip Size/Scale Package), which forms a semiconductor package having the same size as an embedded semiconductor device, is attracting attention. Among CSPs, a wafer level package (WLP) is known as a semiconductor packaging technology for forming a particularly compact and highly integrated package. WLP is a technique for obtaining a semiconductor package by collectively sealing a plurality of semiconductor chips with a sealing resin without using a substrate, and then cutting and separating individual semiconductor chips. In general, when the semiconductor chips are collectively sealed, in order to prevent the semiconductor chips from moving, a plurality of semiconductor chips are temporarily fixed by a predetermined temporary fixing member, and the plurality of semiconductor chips are collectively sealed on the temporary fixing member. After that, when cutting and separating into individual semiconductor chips (after collective sealing and before cutting and separation or after cutting and separation), the temporary fixing material is peeled from the structure including the sealing resin and the semiconductor chip. As a temporary fixing material used in this way, a low-adhesion adhesive sheet is frequently used.

However, when a conventional pressure-sensitive adhesive sheet is used, there is a problem that the residual adhesive is generated in the structure when peeling from the structure including the sealing resin and the semiconductor chip. In particular, there is a problem that the residual pressure-sensitive adhesive in the peripheral portion of the semiconductor chip becomes significant, and the residual pressure-sensitive adhesive causes a decrease in manufacturing efficiency.

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

The present invention has been made to solve the above conventional problems, and its object is to have adequate adhesion to the sealing resin and semiconductor chip constituting the semiconductor package, and can be easily peeled from the sealing resin and the semiconductor chip. In addition, it is to provide a pressure-sensitive adhesive sheet that is less likely to cause residual pressure-sensitive adhesive during peeling.

The pressure-sensitive adhesive sheet of the present invention is a pressure-sensitive adhesive sheet provided with a pressure-sensitive adhesive layer, the contact angle with respect to 4-tert-butylphenylglycidyl ether on the surface of the pressure-sensitive adhesive layer is 15° or more, and polyethylene of the pressure-sensitive adhesive sheet at 23°C. The adhesion to terephthalate is 0.5N/20mm 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 tag value of the pressure-sensitive adhesive layer is 50 N/5 mmφ or more.

In one embodiment, the pressure-sensitive adhesive layer contains an acrylic pressure-sensitive adhesive.

In one embodiment, 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 one embodiment, 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.

In one embodiment, the pressure-sensitive adhesive layer contains a rubber-based pressure-sensitive adhesive.

In one embodiment, the adhesive layer contains a silicone adhesive.

In one embodiment, the silicone pressure-sensitive adhesive includes, as a base polymer, a silicone rubber and a silicone resin, and the weight ratio (rubber:resin) of the silicone rubber and the silicone resin is 100:0 to 100:220.

In one embodiment, the pressure-sensitive adhesive layer further includes thermally expandable microspheres.

In one embodiment, the arithmetic surface roughness Ra of the pressure-sensitive adhesive layer before heating the thermally expandable microspheres is 500 nm or less.

In one embodiment, in the pressure-sensitive adhesive sheet of the present invention, the entire outer surface of the pressure-sensitive adhesive layer is bonded to a bakelite plate under an environmental temperature of 23°C, and aged for 30 minutes under an environmental temperature of 40°C, and thereafter, 1.96 When held for 2 hours while applying a load of 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 includes a substrate layer, and the pressure-sensitive adhesive layer is disposed on one or both sides of the substrate layer.

In one embodiment, the penetration 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 a pressure-sensitive adhesive layer having a contact angle of 15° or more with respect to 4-tert-butylphenylglycidyl ether, it has adequate adhesion to a sealing resin and a semiconductor chip constituting a semiconductor package, and the sealing resin and the semiconductor It can be easily peeled off from the chip, and it is possible to obtain a pressure-sensitive adhesive sheet that is less likely to cause residual pressure-sensitive adhesive during peeling.

1A is a diagram illustrating an example of using a conventional adhesive sheet for manufacturing a semiconductor package, and (b) illustrates an example of using the adhesive sheet of the present invention for manufacturing a semiconductor package. Drawing.
2A and 2B are schematic cross-sectional views of an adhesive sheet according to an embodiment of the present invention.
3 is a schematic cross-sectional view of an adhesive sheet according to an embodiment of the present 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 other than the pressure-sensitive adhesive layer. Examples of the layers other than the pressure-sensitive adhesive layer include a substrate layer capable of functioning as a support, a separator disposed on the pressure-sensitive adhesive layer so as to be peelable. Further, in addition to the pressure-sensitive adhesive layer, a separate pressure-sensitive adhesive layer may be further provided. Another pressure-sensitive adhesive layer may have a known configuration.

The adhesive sheet of the present invention has an adhesive force to polyethylene terephthalate at 23°C, preferably 0.5N/20mm or more, more preferably 0.5N/20mm to 20N/20mm, and further preferably Is 0.5N/20mm to 15N/20mm. In one embodiment, the adhesive force of the adhesive layer of the adhesive sheet of the present invention is reduced by heating or irradiation with light. In this case, the adhesive force before lowering the adhesive force is 2.5N/20mm to 20N/20mm. In addition, in the present specification, "adhesive force to polyethylene terephthalate" means a polyethylene terephthalate film (25 µm thick), and a pressure-sensitive adhesive sheet (20 mm in width x 100 mm in length) is bonded (bonding condition: 2 kg). It refers to the adhesive force measured by applying the sample to a tensile test (peeling speed: 300 mm/min, peeling angle 180°) after leaving for 30 minutes under an environmental temperature of 23°C.

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 0.1N/20mm to 4N/20mm, more preferably 0.15N/20mm to 3N/20mm And more preferably 0.2N/20mm to 2/20mm. Within such a range, a pressure-sensitive adhesive sheet in which adhesion to a semiconductor chip and peelability are compatible can be obtained. The adhesive force to the silicon wafer can also be measured by a method similar to the above "adhesive force to polyethylene terephthalate".

The adhesive strength of the adhesive sheet of the present invention to the epoxy resin sheet at 23° C. is preferably 0.1N/20mm to 5N/20mm, more preferably 0.3N/20mm to 4N/20mm, and further Preferably it is 0.5N/20mm to 3/20mm. If it is such a range, residual adhesive can be suppressed when peeling from the sealing resin (details mentioned later). The adhesive force to the epoxy resin film can also be measured by a method similar to the above "adhesive force to polyethylene terephthalate". In addition, as the epoxy resin film, for example, a film composed of a sealing resin described in the evaluation of the "stand-off suppressing effect" in Examples can be used.

The entire outer surface of the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet (10 mm wide x 150 mm long) of the present invention was bonded to a bakelite plate (10 mm wide x 125 mm long) under an environmental temperature of 23°C, When aging for a minute and then holding for 2 hours while applying a load of 1.96 N, the deviation of the pressure-sensitive adhesive sheet with respect to the bakelite plate is preferably 0.5 mm or less, and more preferably 0.4 mm or less. In addition, here, "the displacement of the adhesive sheet with respect to the bakelite plate" means the amount of movement of the adhesive sheet from the initial state based on the state before aging (initial state). The pressure-sensitive adhesive sheet having a small amount of shift is a pressure-sensitive adhesive sheet in which cohesive destruction of the pressure-sensitive adhesive layer is unlikely to occur, and such a pressure-sensitive adhesive sheet is essentially a pressure-sensitive adhesive sheet in which the pressure-sensitive adhesive hardly remains. If it is such an adhesive sheet, the effect of this invention becomes remarkable. The pressure-sensitive adhesive layer in which cohesive failure is unlikely to occur can be formed, for example, by using the acrylic pressure-sensitive adhesive (preferably, a pressure-sensitive adhesive comprising a crosslinked acrylic polymer as a base polymer) as the pressure-sensitive adhesive for forming the pressure-sensitive adhesive layer. In addition, a rubber-based pressure-sensitive adhesive is used as the pressure-sensitive adhesive, and more specifically, a rubber-based pressure-sensitive adhesive comprising a base polymer (rubber) constituting the rubber-based pressure-sensitive adhesive, a hydroxyl-containing polyolefin, and a crosslinking agent capable of reacting with the hydroxyl group of the hydroxyl-based polyolefin (Rub1 ), by appropriately adjusting the blending amount of the hydroxyl-containing polyolefin and the crosslinking agent, it is possible to form a pressure-sensitive adhesive layer in which cohesive failure is less likely to occur. 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 still more preferably 10 μm to 100 μm.

B. Adhesive layer

The pressure-sensitive adhesive layer has a contact angle on the surface of 4-tert-butylphenylglycidyl ether of 15° or more, more preferably 20° or more, and even more preferably 30° to 100°, It is particularly preferably 40° to 60°.

The adhesive layer of the adhesive sheet of the present invention has an affinity for a sealing resin (for example, an epoxy resin) used when sealing a semiconductor chip and a monomer component constituting the sealing resin. Specifically, the pressure-sensitive adhesive layer is adjusted so that the affinity is lowered within a range in which appropriate adhesion to the sealing resin (and semiconductor chip) can be expressed. In the adhesive layer with appropriate affinity adjusted, the contact angle with respect to 4-tert-butylphenylglycidyl ether exhibits the above range. By adjusting the affinity for the sealing resin and the monomer component constituting the sealing resin in this way, there is little residual adhesive, more specifically, a structure comprising a semiconductor and a resin (or a precursor monomer of the resin) sealing the semiconductor When adhered to (Fig. 1) and then peeled off, an adhesive sheet capable of reducing the components of the adhesive layer adhered to the structure can be obtained. The mechanism by which the residual pressure-sensitive adhesive is reduced by the use of the pressure-sensitive adhesive sheet of the present invention is considered as follows.

Fig. 1A shows an example of a case where a conventional pressure-sensitive adhesive sheet 10' is used for manufacturing a semiconductor package. The adhesive sheet 10' has an adhesive layer, and the outer surface of the adhesive layer is an adhesive surface. Conventionally, in the manufacture of a semiconductor package (CSP), first, the semiconductor chip 1 is adhered on the adhesive sheet 10' (a-i). Thereafter, the semiconductor chip (1) is sealed, a composition (2') containing a monomer that becomes a precursor of the sealing resin (2) is applied (a-ii), and thereafter, the composition (2') is applied. Cure (a-iii). Further, as the composition, for example, a composition containing a naphthalene-type bifunctional epoxy resin (epoxy equivalent: 144) is used. Subsequently, from the structure 20 including the semiconductor chip 1 and the sealing resin 2 before cutting and separating the semiconductor chips individually or after cutting and separating (in the illustrated example, before cutting and separating), The adhesive sheet 10' is peeled off (a-iv). When a conventional pressure-sensitive adhesive sheet is used, residual pressure-sensitive adhesive tends to occur during peeling. In particular, in the peripheral portion of the semiconductor chip 1, the residual adhesive is remarkably seen. Inventors of the present invention, when using the conventional pressure-sensitive adhesive sheet 10', the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet 10' at the time of peeling is raised to surround the bottom of the semiconductor chip 1, and the pressure-sensitive adhesive sheet at the time of peeling It was found that in the pressure-sensitive adhesive layer of (10'), a step (hereinafter also referred to as stand-off) caused by the bottom of the semiconductor chip 1 occurred. It is considered that the cohesive failure of the pressure-sensitive adhesive layer occurs when the stress derived from the semiconductor chip 1 is concentrated on the stand-off portion, and as a result, the residual pressure-sensitive adhesive occurs.

1B shows an example in which the pressure-sensitive adhesive sheet 10 of the present invention is used for manufacturing a semiconductor package. The adhesive sheet 10 has an adhesive layer, and the outer surface of the adhesive layer is an adhesive surface. In FIG. 1(b), the semiconductor chip 1 and the sealing resin on the pressure-sensitive adhesive sheet 10 are performed by the same operation as that shown in FIG. 1(a), except that the pressure-sensitive adhesive sheet is changed. The structure 20 containing 2) is formed, and after that, the adhesive sheet 10 is peeled. When the pressure-sensitive adhesive sheet 10 of the present invention is used, the stand-off occurring in the pressure-sensitive adhesive sheet 10 is very small (or does not occur), and residual pressure-sensitive adhesive is suppressed.

In the conventional pressure-sensitive adhesive sheet 10', the pressure-sensitive adhesive layer component is transferred to the composition or sealing resin containing a monomer that becomes a precursor of the sealing resin 2, and as a result, the resin layer of the pressure-sensitive adhesive sheet 10' It is thought that it is raised by surrounding the bottom of the semiconductor chip 1 and standoff occurs. In addition, the presence or absence of component migration can be confirmed by spectral analysis by FT-IR or the like. On the other hand, in the present invention, since the affinity of the adhesive layer to the sealing resin used when sealing the semiconductor chip and the monomer component constituting the sealing resin is adjusted, the above component migration is suppressed and stand-off. Is very small (or does not occur), and as a result, it is considered that residual pressure-sensitive adhesive is suppressed. In the following, in this specification, the sealing resin used when sealing the semiconductor chip and the monomer component constituting the sealing resin are collectively referred to as a sealing material.

The pressure-sensitive adhesive layer contains an 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 , more preferably 7 (cal/cm 3) ^1/2 To 9.1 (cal/cm 3) ^1/2 , more preferably 7 (cal/cm 3) ^1/2 to 8 (cal/cm 3) ^1/2 . If it is such a range, it is possible to form a pressure-sensitive adhesive layer that has an appropriate adhesiveness, has low affinity with a sealing material, and is unlikely to cause standoff. In the pressure-sensitive adhesive sheet provided with such a pressure-sensitive adhesive layer, residual pressure-sensitive adhesive is less likely to occur. In addition, the material constituting the pressure-sensitive adhesive herein refers to a polymer such as a base polymer contained in the pressure-sensitive adhesive (base polymer after crosslinking when crosslinking), rubber (rubber after crosslinking when crosslinking), and tackifier. . In the present invention, it is preferable that at least the sp value of the base polymer (the base polymer after crosslinking when crosslinking) or the rubber (rubber after crosslinking when crosslinking), which is the main component of the pressure-sensitive adhesive, is in the above range.

In one embodiment, 1,3-bis(N,N-diclycidylaminomethyl)cyclohexane is brought into contact with the surface of the pressure-sensitive adhesive layer, and placed in an environment of 50° C. for 2 hours, with respect to the pressure-sensitive adhesive surface, When the absorbance of the glycidyl group-derived peak is measured by FT-IR measurement, the absorbance ratio of the glycidyl group-derived peak is preferably 1.3 or less with respect to the absorbance 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. In addition, the "initial pressure-sensitive adhesive layer" means the pressure-sensitive adhesive layer before contacting 1,3-bis(N,N-diclycidylaminomethyl)cyclohexane. In another embodiment, 1,3-bis(N,N-diclycidylaminomethyl)cyclohexane was brought into contact with the surface of the pressure-sensitive adhesive layer, and left in an environment at 50° C. for 2 hours, and FT- When IR measurement (e.g., attenuated total reflection method (ATR method)), with respect to the absorbance at the wavenumber (near 850 cm ^-1 ) at which the glycidyl group-derived peak occurs, the amount of increase from the initial pressure-sensitive adhesive layer is, It is preferably 0.3 or less, more preferably 0.1 or less. Here, 1,3-bis(N,N-diclycidylaminomethyl)cyclohexane is an epoxy compound that can be used as a resin material for sealing semiconductor chips. Even when the epoxy compound is brought into contact, if the adhesive layer is formed in which the epoxy compound is difficult to migrate as described above, even when used in the manufacture of a semiconductor package, stand-off is unlikely to occur, and a pressure-sensitive adhesive sheet with little residual adhesive can be obtained.

The thickness of the pressure-sensitive adhesive layer is preferably 1 μm to 300 μm, more preferably 3 μm to 300 μm, still more preferably 5 μm to 150 μm, still more preferably 10 μm to 100 μm, More preferably, it is 10 micrometers-50 micrometers. As described later, when the pressure-sensitive adhesive layer contains thermally 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. It is more preferable. Within this range, a pressure-sensitive adhesive layer having excellent surface smoothness and excellent adhesion can be formed. When the pressure-sensitive adhesive layer does not contain thermally expandable microspheres, the thickness of the pressure-sensitive adhesive layer is preferably 50 μm or less, more preferably 1 μm to 50 μm, and still 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 still more preferably 0.1 MPa to 10 MPa. Within this range, it is possible to obtain an adhesive sheet having an appropriate adhesive force as an adhesive sheet that can be used for manufacturing a semiconductor package. The elastic modulus by the nano-indentation method is obtained from the obtained load load-indentation depth curve by continuously measuring the load load and the indentation depth on the indenter when the indenter is pressed into the sample during loading and unloading. It refers to the modulus of elasticity. In the present specification, the elastic modulus by the nanoindentation method refers to the elastic modulus measured as described above with measurement conditions as load: 1 mN, load/unload speed: 0.1 mN/s, and holding time: 1 s.

The tensile 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 still more preferably 0.1 MPa to 10 MPa. Within this range, it is possible to obtain an adhesive sheet having an appropriate adhesive force as an adhesive sheet that can be used for manufacturing a semiconductor package. In addition, the tensile modulus can be measured according to JIS K 7161:2008.

The probe tag value of the pressure-sensitive adhesive layer is preferably 50N/5mmφ or more, more preferably 75N/5mmφ or more, and still more preferably 100N/5mmφ or more. Within such a range, the adherend is excellent in retainability and, for example, when the semiconductor chip is temporarily fixed, unnecessary positional shift of the semiconductor chip can be prevented. The measuring method of the probe tag 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 effect of the present invention is 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 acrylic pressure-sensitive adhesives, rubber pressure-sensitive adhesives, and silicone pressure-sensitive adhesives. Among them, an acrylic pressure-sensitive adhesive can be preferably used. Further, as the pressure-sensitive adhesive, an active energy ray-curable pressure-sensitive adhesive may be used.

(Acrylic adhesive)

Examples of the acrylic pressure-sensitive adhesive include an acrylic pressure-sensitive adhesive comprising an acrylic polymer (a single polymer or a copolymer) in which one or two or more of alkyl (meth)acrylate is used as a monomer component as a base polymer.

The acrylic polymer, as a side chain, preferably has an alkyl ester having 4 or more carbon atoms, more preferably an alkyl ester having 6 or more carbon atoms, even more preferably an alkyl ester having 8 or more carbon atoms, and has 8 to carbon atoms It is particularly preferred to have an alkyl ester of 20, and most preferred to have an alkyl ester of 8 to 18 carbon atoms. When an acrylic polymer having a long side chain is used, a pressure-sensitive adhesive layer having low affinity with a sealing material can be formed. In the acrylic polymer, the content ratio of the constituent units having an alkyl ester having 4 or more carbon atoms as a side chain is preferably 30% by weight or more, and more preferably 50% by weight, based on the total constituent units constituting the acrylic polymer. % Or more, more preferably 70% by weight to 100% by weight, particularly preferably 80% by weight to 100% by weight. Within such a range, an adhesive layer having low affinity with a sealing material can be formed.

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

Specific examples of the (meth)acrylate alkyl ester include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, ( S-butyl meth)acrylate, t-butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, (meth)acrylate )Isooctyl acrylate, Nonyl (meth)acrylate, Isononyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, undecyl (meth)acrylate, dodecyl (meth)acrylate, tri(meth)acrylic acid Decyl, tetradecyl (meth)acrylate, pentadecyl (meth)acrylate, hexadecyl (meth)acrylate, heptadecyl (meth)acrylate, octadecyl (meth)acrylate, nonadecyl (meth)acrylate, eicosyl (meth)acrylate (Meth)acrylic acid C1-20 alkyl esters such as are mentioned. Among them, preferably, it is 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), and more preferably Is 2-ethylhexyl (meth)acrylate.

The acrylic polymer may contain a unit corresponding to another monomer component copolymerizable with the alkyl (meth)acrylate, if necessary, for the purpose of modifying cohesive strength, heat resistance, crosslinkability, and the like. Examples of such a monomer component include carboxyl group-containing monomers such as acrylic acid, methacrylic acid, carboxyethyl acrylate, carboxypentyl acrylate, itaconic acid, maleic acid, fumaric acid, and crotonic acid; Acid anhydride monomers such as maleic anhydride and itaconic anhydride; Hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, hydroxyhexyl (meth)acrylate, hydroxyoctyl (meth)acrylate, hydroxydecyl (meth)acrylate, (meth)acrylate ) Hydroxyl group-containing monomers such as hydroxylauryl acrylic acid and (4-hydroxymethylcyclohexyl)methylmethacrylate; Contains sulfonic acid groups such as styrenesulfonic acid, allylsulfonic acid, 2-(meth)acrylamide-2-methylpropanesulfonic acid, (meth)acrylamide propanesulfonic acid, sulfopropyl (meth)acrylate, and (meth)acryloyloxynaphthalenesulfonic acid Monomer; (N, such as (meth)acrylamide, N,N-dimethyl (meth)acrylamide, N-butyl (meth)acrylamide, N-methylol (meth)acrylamide, and N-methylolpropane (meth)acrylamide, etc. -Substituted) amide-based monomer; Aminoalkyl (meth)acrylate monomers such as aminoethyl (meth)acrylate, N,N-dimethylaminoethyl (meth)acrylate, and t-butylaminoethyl (meth)acrylate; Alkoxyalkyl (meth)acrylate monomers such as methoxyethyl (meth)acrylate and ethoxyethyl (meth)acrylate; Maleimide-based monomers such as N-cyclohexylmaleimide, N-isopropylmaleimide, N-laurylmaleimide, and N-phenylmaleimide; N-methyl itaconimide, N-ethyl itaconimide, N-butyl itaconimide, N-octyl itaconimide, N-2-ethylhexyl itaconimide, N-cyclohexyl itacone Itaconimide-based monomers such as mid and N-lauryl itaconimide; N-(meth)acryloyloxymethylenesuccinimide, N-(meth)acryloyl-6-oxyhexamethylenesuccinimide, N-(meth)acryloyl-8-oxyoctamethylenesuccinimide, etc. Succinimide-based monomer of; Vinyl acetate, vinyl propionate, N-vinylpyrrolidone, methylvinylpyrrolidone, vinylpyridine, vinylpiperidone, vinylpyrimidine, vinylpiperazine, vinylpyrazine, vinylpyrrole, vinylimidazole, vinyloxazole, vinyl Vinyl monomers such as morpholine, N-vinylcarboxylic acid amide, styrene, α-methylstyrene, and N-vinyl caprolactam; Cyanoacrylate monomers such as acrylonitrile and methacrylonitrile; Epoxy group-containing acrylic monomers such as glycidyl (meth)acrylate; Glycol-based acrylic ester monomers such as polyethylene glycol (meth)acrylate, polypropylene glycol (meth)acrylate, methoxyethylene glycol (meth)acrylate, and methoxypolypropylene glycol (meth)acrylate; Acrylic acid ester monomers having heterocycles such as tetrahydrofurfuryl (meth)acrylate, fluorine (meth)acrylate, and silicone (meth)acrylate, halogen atoms, silicon atoms, and the like; Hexanediol di(meth)acrylate, (poly)ethylene glycol di(meth)acrylate, (poly)propylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, pentaerythritol di(meth) Multifunctionality such as acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, epoxy acrylate, polyester acrylate, urethane acrylate, etc. Monomer; Olefinic monomers such as isoprene, butadiene, and isobutylene; Vinyl ether-based monomers, such as vinyl ether, etc. are mentioned. These monomer components may be used alone or in combination of two or more. Among the above, more preferably a carboxyl group-containing monomer (particularly preferably acrylic acid) or a hydroxyl group-containing monomer (particularly preferably hydroxyethyl (meth)acrylate). The content of the constituent units 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, particularly preferably, based on the total constitutional units constituting the acrylic polymer. Is 1% to 4% by weight. In addition, 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 to 10% by weight, based on all the structural units constituting the acrylic polymer. , Particularly preferably 1% to 7% by weight.

The acrylic pressure-sensitive adhesive may contain any suitable additives, if necessary. Examples of the additives include crosslinking agents, tackifiers, plasticizers (for example, trimellitic acid ester plasticizers, pyromellitic acid ester plasticizers, etc.), pigments, dyes, fillers, aging inhibitors, conductive materials, antistatic agents, UV absorbers, light stabilizers, peeling modifiers, softeners, surfactants, flame retardants, antioxidants, and the like.

Examples of the crosslinking agent contained in the acrylic pressure-sensitive adhesive include isocyanate crosslinking agents, epoxy crosslinking agents, melamine crosslinking agents, peroxide crosslinking agents, urea crosslinking agents, metal alkoxide crosslinking agents, metal chelate crosslinking agents, metal salt crosslinking agents, carbodiimide. And an oxazoline crosslinking agent, an aziridine crosslinking agent, and an amine crosslinking agent. Among them, an isocyanate crosslinking agent or an epoxy crosslinking agent is preferred.

Specific examples of the isocyanate-based crosslinking agent contained in the acrylic pressure-sensitive adhesive include lower aliphatic polyisocyanates such as butylene diisocyanate and hexamethylene diisocyanate; Alicyclic isocyanates such as cyclopentylene diisocyanate, cyclohexylene diisocyanate, and isophorone diisocyanate; Aromatic isocyanates such as 2,4-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, and xylylene isocyanate; Trimethylolpropane/tolylenediisocyanate trimer adduct (manufactured by Nippon Polyurethane Co., Ltd., brand name ``Coronate L''), trimethylolpropane/hexamethylene diisocyanate trimer adduct (manufactured by Nippon Polyurethane Co., Ltd., brand name ``Coronate HL'' &Quot;) and isocyanate adducts such as an isocyanurate product of hexamethylene diisocyanate (manufactured by Nippon Polyurethane Co., Ltd., brand name "Coronate HX"); And the like. The content of the isocyanate-based crosslinking agent may be set in any suitable amount depending on the desired adhesive strength, and is typically 0.1 parts by weight to 20 parts by weight, and more preferably 0.5 parts by weight to 100 parts by weight of the base polymer. It is 10 parts by weight.

Examples of the epoxy-based crosslinking agent contained in the acrylic pressure-sensitive adhesive include N,N,N',N'-tetraglycidyl-m-xylenediamine, diglycidylaniline, 1,3-bis(N,N -Glycidylaminomethyl)cyclohexane (manufactured by Mitsubishi Gas Chemical, brand name ``Tetrad C''), 1,6-hexanediol diglycidyl ether (manufactured by Kyoesha Chemical, brand name ``Epolite 1600'') , Neopentyl glycol diglycidyl ether (Kyoesha Chemical Co., Ltd., brand name ``Epolite 1500NP''), ethylene glycol diglycidyl ether (Kyoesha Chemical Co., Ltd. product, brand name ``Epolite 40E''), propylene glycol Diglycidyl ether (manufactured by Kyoesha 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, brand name ``Epiol P-200''), sorbitol polyglycidyl ether (manufactured by Nagase Chemtex, brand name ``Denacol EX-611''), glycerol polyglycidyl ether (manufactured by Nagase Chemtex, Brand name ``Denacol EX-314''), pentaerythritol polyglycidyl ether, polyglycerol polyglycidyl ether (manufactured by Nagase Chemtex, brand name ``Denacol EX-512''), sorbitan polyglycidyl ether, Trimethylolpropane polyglycidyl ether, adipic acid diglycidyl ester, o-phthalic acid diglycidyl ester, triglycidyl-tris (2-hydroxyethyl) isocyanurate, 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 crosslinking agent may be set in any suitable amount depending on the desired adhesive strength, and is typically 0.01 parts by weight to 10 parts by weight, more preferably 0.03 parts by weight to 100 parts by weight of the base polymer. It is 5 parts by weight.

As the tackifier contained in the acrylic pressure-sensitive adhesive, any suitable tackifier is used. As the tackifier, for example, a tackifier resin is used. Specific examples of the tackifying resin include rosin-based tackifying resins (e.g., unmodified rosin, modified rosin, rosin phenolic resins, rosin ester-based resins, etc.), terpene-based tackifying resins (for example, terpene-based resins) , Terpenephenol resin, styrene modified terpene resin, aromatic modified terpene resin, hydrogenated terpene resin), hydrocarbon tackifying resin (e.g., aliphatic hydrocarbon resin, aliphatic cyclic hydrocarbon resin, aromatic hydrocarbon resin (For example, styrene resins, xylene resins, etc.), aliphatic/aromatic petroleum resins, aliphatic/alicyclic petroleum resins, hydrogenated hydrocarbon resins, coumarone resins, coumarone indene resins, etc.), phenolic tackifier resins (For example, alkylphenol resin, xylene formaldehyde resin, resol, novolac, etc.), ketone tackifier resin, polyamide tackifier resin, epoxy tackifier resin, elastomer tackifier resin, etc. I can. Among them, a rosin-based tackifying resin, a terpene-based tackifying resin, or a hydrocarbon-based tackifying resin (such as a styrene-based resin) is preferred. The tackifier may be used alone or in combination of two or more. The added amount of the tackifier is preferably 5 parts by weight to 100 parts by weight, and more preferably 10 parts by weight to 50 parts by weight, based on 100 parts by weight of the base polymer.

Preferably, as the tackifying resin, a resin having a high softening point or glass transition temperature (Tg) is used. When a resin with a high softening point or glass transition temperature (Tg) is used, a pressure-sensitive adhesive layer capable of expressing high adhesion is formed even in a high-temperature environment (for example, in a high-temperature environment in processing during semiconductor chip sealing). can do. The softening point of the tackifier is preferably 100°C to 180°C, more preferably 110°C to 180°C, and still more preferably 120°C to 180°C. The glass potential temperature (Tg) of the tackifier is preferably 100°C to 180°C, more preferably 110°C to 180°C, and still more preferably 120°C to 180°C.

Preferably, as the tackifying resin, a low-polar tackifying resin is used. When a low-polar tackifying resin is used, a pressure-sensitive adhesive layer having a low affinity with a sealing material can be formed. Examples of low-polarity tackifying resins include aliphatic hydrocarbon resins, aliphatic cyclic hydrocarbon resins, aromatic hydrocarbon resins (e.g., styrene resins, xylene resins, etc.), aliphatic/aromatic petroleum resins, aliphatic -An alicyclic petroleum resin and a hydrocarbon-based tackifying resin per hydrogenated hydrocarbon resin are mentioned. Among them, preferably, it is a tackifier having 5 to 9 carbon atoms. This is because such a tackifier has low polarity, has excellent compatibility with an acrylic polymer, does not phase-separate over a wide temperature range, and can form a pressure-sensitive adhesive layer having excellent stability.

The acid value of the tackifying resin is preferably 40 or less, more preferably 20 or less, and still more preferably 10 or less. Within such a range, an adhesive layer having low affinity with a sealing material can be formed. The hydroxyl value of the tackifying resin is preferably 60 or less, more preferably 40 or less, and still more preferably 20 or less. Within such a range, an adhesive layer having low affinity with a 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 effect of the present invention is obtained. As the rubber-based adhesive, for example, natural rubber; Polyisoprene rubber, butadiene rubber, styrene/butadiene (SB) rubber, styrene/isoprene (SI) rubber, styrene/isoprene/styrene block copolymer (SIS) rubber, styrene/butadiene/styrene block copolymer (SBS) rubber, styrene Ethylene/butylene/styrene block copolymer (SEBS) rubber, styrene/ethylene/propylene/styrene block copolymer (SEPS) rubber, styrene/ethylene/propylene block copolymer (SEP) rubber, recycled rubber, butyl rubber, poly Synthetic rubbers such as isobutylene rubber or modified products thereof; A rubber-based pressure-sensitive adhesive having the like as a base polymer is preferably used. This base polymer (rubber) has a low sp value, and when the base polymer is used, a pressure-sensitive adhesive layer having low affinity with a sealing material can be formed.

As the base polymer constituting the rubber-based adhesive, polyisobutylene rubber, polyisoprene rubber, or butyl rubber is particularly preferably used. When this rubber is used, it is possible to form a pressure-sensitive adhesive layer having excellent semiconductor chip retention at room temperature and excellent peelability. Further, a pressure-sensitive adhesive layer having low affinity with a sealing material can be formed.

As the base polymer constituting the rubber-based adhesive, styrene/ethylene/propylene block copolymer (SEP) rubber, styrene/ethylene/butylene/styrene block copolymer (SEBS) rubber, and styrene/isoprene/styrene block copolymer (SIS) Rubber, styrene-butadiene-styrene block copolymer (SBS) rubber, and propylene rubber can also be preferably used. When this rubber is used, a pressure-sensitive adhesive layer capable of expressing high tackiness can be formed even in a high-temperature environment (for example, in a high-temperature environment in processing during semiconductor chip sealing). In the base polymer (rubber) having structural units derived from styrene, the content ratio of the structural units derived from styrene is preferably 15% by weight or more with respect to all structural units in the base polymer.

The rubber-based pressure-sensitive adhesive may contain any suitable additives, if necessary. Examples of the additives include crosslinking agents, vulcanizing agents, tackifiers, plasticizers, pigments, dyes, fillers, anti-aging agents, conductive materials, antistatic agents, ultraviolet absorbers, light stabilizers, release modifiers, softeners, surfactants, flame retardants, and oxidation agents. Inhibitors, etc. are mentioned.

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

Examples of the rosin-based resin contained in the rubber-based adhesive include gum rosin, wood rosin, and tall rosin. As the rosin-based resin, a stabilized rosin obtained by disproportionating or hydrogenating any suitable rosin may be used. In addition, as the rosin-based resin, a polymerized rosin, which is a multimer (typically a dimer) of any suitable rosin, or a modified rosin obtained by modifying (e.g., modifying with an unsaturated acid) any suitable rosin may be used. .

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

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

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

Examples of the ketone resin contained in the rubber pressure-sensitive adhesive include ketone resins obtained by condensing ketones (eg, aliphatic ketones, alicyclic ketones) and formaldehyde.

Examples of the crosslinking agent contained in the rubber pressure sensitive adhesive include an isocyanate crosslinking agent. Examples of the vulcanizing agent contained in the rubber-based pressure-sensitive adhesive include thiuram-based vulcanizing agents, quinoid-based vulcanizing agents, and quinone dioxime-based vulcanizing agents. When a crosslinking agent and/or a vulcanizing agent are contained in the rubber-based pressure-sensitive adhesive, a pressure-sensitive adhesive layer having high cohesiveness and hardly remaining pressure-sensitive adhesive can be formed. The total content of the crosslinking agent and the vulcanizing agent is typically 0.1 parts by weight to 20 parts by weight, more preferably 0.1 parts by weight to 10 parts by weight, based on 100 parts by weight of the base polymer.

In one embodiment, a rubber-based pressure-sensitive adhesive (Rub1) comprising the base polymer (rubber), a hydroxyl group-containing polyolefin, and a crosslinking agent a capable of reacting with a hydroxyl group of the hydroxyl group polyolefin is used. In this rubber-based pressure-sensitive adhesive, the base polymer is not directly crosslinked, but entanglement between the base polymer and the crosslinked hydroxyl group-containing polyolefin occurs, resulting in a so-called pseudo crosslinking. As a result, an adhesive layer having high cohesiveness and hardly remaining adhesive can be formed. As the base polymer (rubber) used in this embodiment, the synthetic rubber is preferably used. In addition, as a crosslinking agent used in this embodiment, an isocyanate-based crosslinking agent is preferably used.

The blending amount of the hydroxyl group-containing polyolefin is preferably 0.5 parts by weight or more, and more preferably 1.0 part by weight or more, based on 100 parts by weight of the total of the base polymer (rubber), the hydroxyl group-containing polyolefin, and the crosslinking agent a. In such a range, an adhesive layer having high cohesiveness can be formed. In addition, when the pressure-sensitive adhesive sheet includes a base material layer, the adhesion between the base material layer and the pressure-sensitive adhesive layer can be improved. That is, when the blending amount of the hydroxyl group-containing polyolefin is within the above range, a pressure-sensitive adhesive sheet with little residual pressure-sensitive adhesive can be obtained.

The blending amount of the crosslinking agent a is preferably 0.5 parts by weight or more, and more preferably 1.0 parts by weight or more, based on 100 parts by weight of the total of the base polymer (rubber), the hydroxyl group-containing polyolefin, and the crosslinking agent a. In such a range, an adhesive layer having high cohesiveness can be formed. In addition, when the pressure-sensitive adhesive sheet includes a base material layer, the adhesion between the base material layer and the pressure-sensitive adhesive layer can be improved. That is, when the blending amount of the crosslinking agent a is within the above range, a pressure-sensitive adhesive sheet with little residual pressure-sensitive adhesive can be obtained.

As the hydroxyl group-containing polyolefin, a resin excellent in compatibility with the synthetic rubber is preferably used. Examples of the hydroxyl-containing polyolefin include polyethylene polyol, polypropylene polyol, polybutadiene polyol, hydrogenated polybutadiene polyol, polyisoprene polyol, hydrogenated polyisoprene polyol, and the like. Among them, from the viewpoint of compatibility with the synthetic rubber, hydrogenated polyisoprene polyol, polyisoprene polyol, and polybutadiene polyol are preferred.

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 still more preferably 1,200 to 150,000. The number average molecular weight can be measured based on 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 pressure-sensitive adhesive, any suitable pressure-sensitive adhesive can be used as long as the effect of the present invention is obtained. As the silicone pressure-sensitive adhesive, for example, a silicone pressure-sensitive adhesive made of a silicone rubber or silicone resin containing organopolysiloxane as a base polymer is preferably used. As the base polymer constituting the silicone pressure-sensitive adhesive, a base polymer obtained by crosslinking the silicone rubber or silicone resin may be used. In addition, in this specification, "silicone rubber" means a polymer (for example, viscosity 1000 Pa·s) in which diorganosiloxane (D unit) as a main component is connected in a straight chain, and "silicone resin" means a main component Refers to a polymer composed of triorganosylhemioxane (unit M) and silicate (unit Q) as ("material design and functionality of adhesives (film tape)", Technical Information Association, published on September 30, 2009 ).

Examples of the silicone rubber include organopolysiloxanes containing dimethylsiloxane as a structural unit. In the organopolysiloxane, a functional group (for example, a vinyl group) may be introduced as 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).

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

The silicone rubber and silicone resin may be used in combination. The weight ratio (rubber:resin) of the silicone rubber and the silicone resin in the silicone pressure-sensitive adhesive is preferably 100:0 to 100:220, more preferably 100:0 to 100:180, even more preferably 100:10 to It is 100:100. The silicone rubber and the silicone resin may be contained in the silicone pressure-sensitive adhesive as a simple mixture, or may be contained in the silicone pressure-sensitive adhesive in a form in which the silicone rubber and the silicone resin are partially condensed. The rubber:resin ratio can also be obtained from the ratio of the Q unit (resin) and 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 additives, if necessary. Examples of the additives include crosslinking agents, vulcanizing agents, tackifiers, plasticizers, pigments, dyes, fillers, anti-aging agents, conductive materials, antistatic agents, ultraviolet absorbers, light stabilizers, release modifiers, softeners, surfactants, flame retardants, and oxidation agents. Inhibitors, etc. are mentioned.

Preferably, the silicone-based adhesive includes a crosslinking agent. Examples of the crosslinking agent include a siloxane crosslinking agent and a peroxide crosslinking agent. As the peroxide-based crosslinking agent, any suitable crosslinking agent can be used. As a peroxide type crosslinking agent, benzoyl peroxide, t-butyl peroxybenzoate, dicumyl peroxite, etc. are mentioned, for example. As a siloxane-type crosslinking agent, polyorganohydrogensiloxane etc. are mentioned, for example. It is preferable that the polyorganohydrogensiloxane has two or more hydrogen atoms bonded to a silicon atom. Further, the polyorganohydrogensiloxane preferably has an alkyl group, a phenyl group, or a halogenated alkyl 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 (higher modulus of elasticity) by irradiation with active energy rays may be used. When an active energy ray-curable adhesive is used, it is possible to obtain a pressure-sensitive adhesive sheet capable of lowering the adhesive strength by irradiating an active energy ray in a scene where it has low elasticity, high flexibility, and excellent handling properties at the time of attachment, and in a scene requiring peeling. have. Examples of the active energy rays include gamma rays, ultraviolet rays, visible rays, infrared rays (heat rays), radio waves, alpha rays, beta rays, electron rays, plasmas, ionizing rays, particle rays, and the like. In addition, in the present specification, in the case of simply "adhesive layer", it means the pressure-sensitive adhesive layer before the pressure-sensitive adhesive is cured and the adhesive strength is lowered.

As a resin material constituting the active energy ray-curable pressure-sensitive adhesive, for example, an ultraviolet curing system (Kato Kiyomi, published by the General Technology Center, (1989)), photocuring technology (Technical Information Association edition (2000)), Japanese patents Resin materials described in Unexamined Publication No. 2003-292916, Patent No. 4151850, and the like can be mentioned. More specifically, a resin material (R1) containing a polymer used as a parent agent and an active energy ray-reactive compound (monomer or oligomer), a resin material (R2) containing an active energy ray-reactive polymer, and the like can be mentioned.

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

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, tetramethylolmethane tetra(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate. Rate, dipentaerythritol monohydroxypenta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylic (Meth)acryloyl group-containing compounds such as rate and polyethylene glycol di(meth)acrylate; 2 to pentamer of this (meth)acryloyl group-containing compound; And the like.

Further, as the active energy ray-reactive compound, monomers such as epoxidized butadiene, glycidyl methacrylate, acrylamide, and vinylsiloxane; Alternatively, an oligomer composed of the above monomers may be used. The resin material (R1) containing these compounds can be cured with 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, an organic salt is cleaved by irradiation with an active energy ray (e.g., ultraviolet rays, electron beam) to generate ions, which become an initiating species and cause a ring-opening reaction of a heterocycle, thereby forming a three-dimensional mesh structure. . Examples of the organic salts include iodonium salts, phosphonium salts, antimonium salts, sulfonium salts, and borate salts. Examples of the heterocycle in the compound having a plurality of heterocycles in the molecule include oxirane, oxetane, oxorane, thiirane, aziridine, and the like.

In the resin material (R1) containing the polymer used as the parent agent and the active energy ray-reactive compound, the content ratio of the active energy ray reactive compound is preferably 0.1 to 500 parts by weight based on 100 parts by weight of the polymer used as the parent agent. It is a part by weight, more preferably 1 part by weight to 300 parts by weight, still more preferably 10 parts by weight to 200 parts by weight. Within such a range, an adhesive layer having low affinity with a sealing material can be formed.

The resin material (R1) containing the polymer used as the parent agent and the active energy ray-reactive compound may contain any suitable additives, if necessary. As an additive, an active energy ray polymerization initiator, an active energy ray polymerization accelerator, a crosslinking agent, a plasticizer, a vulcanizing agent, etc. are mentioned, for example. As the active energy ray polymerization initiator, any suitable initiator can be used depending on the type of active energy ray to be 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 used as the parent agent and the active energy ray-reactive compound, the content ratio of the active energy ray polymerization initiator is preferably 0.1 parts by weight to 10 parts by weight based on 100 parts by weight of the polymer used as the parent agent. Parts, more preferably 1 to 5 parts by weight.

Examples of the active energy ray-reactive polymer include a polymer 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. As a specific example of the polymer which has an active energy ray-reactive functional group, the polymer etc. comprised from polyfunctional (meth)acrylate are mentioned. The polymer composed of the polyfunctional (meth)acrylate preferably has an alkyl ester having 4 or more carbon atoms, more preferably an alkyl ester having 6 or more carbon atoms, and even more preferably an alkyl ester having 8 or more carbon atoms. And, it is particularly preferable to have an alkyl ester having 8 to 20 carbon atoms, and most preferably an alkyl ester having 8 to 18 carbon atoms. When a polymer having a long side chain is used, a pressure-sensitive adhesive layer having low affinity with a sealing material can be formed. In the polymer, the content ratio of the constituent units having an alkyl ester having 4 or more carbon atoms as a side chain is preferably 30% by weight or more, and more preferably 50% by weight or more with respect to all the constituent units constituting the polymer. It is, more preferably 70% by weight to 100% by weight, particularly preferably 80% by weight to 100% by weight. Within such a range, an adhesive layer having low affinity with a 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 appropriate additive, if necessary. The specific example of the additive is the same as the additive that can be contained in the resin material (R1) containing the polymer used as the parent agent 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 parts by weight to 10 parts by weight based on 100 parts by weight of the active energy ray reactive polymer, more It is preferably 1 to 5 parts by weight.

<Thermal expandable microsphere>

In one embodiment, the pressure-sensitive adhesive layer further includes thermally expandable microspheres. When the pressure-sensitive adhesive sheet provided with the pressure-sensitive adhesive layer including thermally expandable microspheres is heated, the thermally expandable microspheres are expanded or foamed to cause irregularities on the adhesive surface, and as a result, the adhesive strength is reduced or disappeared. Such an adhesive sheet can be easily peeled off by heating.

As the thermally expandable microspheres, any suitable thermally expandable microspheres can be used as long as they are microspheres that can expand or foam by heating. As the thermally expandable microspheres, for example, microspheres in which a material that is easily expanded by heating is enclosed in an elastic shell may be used. Such thermally expandable microspheres can be produced by any suitable method, for example, a core cervation method, an interfacial polymerization method, or the like.

Examples of substances that are easily expanded by heating include propane, propylene, butene, normal butane, isobutane, isopentane, neopentane, normal pentane, normal hexane, isohexane, heptane, octane, petroleum ether, methane halogen Low-boiling liquids such as cargo and tetraalkylsilane; Azodicarbonamide gasified by thermal decomposition; And the like.

Examples of the material constituting the shell include nitrile monomers such as acrylonitrile, methacrylonitrile, α-chloracrylonitrile, α-ethoxyacrylonitrile, and fumaronitrile; Carboxylic acid monomers such as acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, and citraconic acid; Vinylidene chloride; Vinyl acetate; Methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, isobornyl (meth)acrylate, cyclo (Meth)acrylic acid esters such as hexyl (meth)acrylate, benzyl (meth)acrylate, and β-carboxyethyl acrylate; Styrene monomers such as styrene, α-methylstyrene, and chlorostyrene; Amide monomers such as acrylamide, substituted acrylamide, methacrylamide, and substituted methacrylamide; A polymer composed of, etc. is mentioned. The polymer composed of this monomer 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, Acrylonitrile-methacrylonitrile-itaconic acid copolymer, etc. are mentioned.

As the thermally expandable microspheres, an inorganic foaming agent or an organic foaming agent may be used. Examples of the inorganic foaming agent include ammonium carbonate, ammonium hydrogen carbonate, sodium hydrogen carbonate, ammonium nitrite, sodium boron hydroxide, and various azides. Further, examples of the organic foaming agent include salt fluorinated alkane compounds such as trichloromonofluoromethane and dichloromonofluoromethane; Azo compounds such as azobisisobutyronitrile, azodicarbonamide, and barium azodicarboxylate; Hydrazine compounds such as paratoluenesulfonylhydrazide, diphenylsulfone-3,3'-disulfonylhydrazide, 4,4'-oxybis (benzenesulfonylhydrazide), and allyl bis (sulfonylhydrazide) ; semicarbazide compounds such as p-toluylenesulfonyl semicarbazide and 4,4'-oxybis(benzenesulfonyl semicarbazide); Triazole compounds such as 5-morphoryl-1,2,3,4-thiatriazole; N,N'-dinitrosopentamethylenetetramine, N,N'-dimethyl-N,N'-dinitrosoterephthalamide; N-nitroso compounds, such as, etc. are mentioned.

As the thermally expandable microsphere, a commercial item may be used. As a specific example of a commercially available thermally expandable microsphere, the brand name ``Matsumoto Micro Spare'' manufactured by Matsumoto Yushi Seiyaku (grades: F-30, F-30D, F-36D, F-36LV, F-50, F-50D, F-65, F-65D, FN-100SS, FN-100SSD, FN-180SS, FN-180SSD, F-190D, F-260D, F-2800D), Nippon Pyrite's brand name ``Xpantle'' (grade: 053-40, 031-40, 920-40, 909-80, 930-120), Kureha Chemical High School ``Die Form'' (Grade: H750, H850, H1100, S2320D, S2640D, M330, M430, M520) , Sekisui Chemical Co., Ltd. "Advancel" (grades: EML101, EMH204, EHM301, EHM302, EHM303, EM304, EHM401, EM403, EM501), and the like.

The particle diameter of the thermally 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 It is 15 μm. Therefore, when the particle size before heating of the thermally expandable microspheres is referred to as an average particle diameter, it is preferably 6 µm to 45 µm, more preferably 15 µm to 35 µm. The said particle diameter and the average particle diameter are values calculated|required by the particle size distribution measurement method in a laser scattering method.

It is preferable that the thermally expandable microspheres have an appropriate strength that does not rupture until the volume expansion rate is preferably 5 times or more, more preferably 7 times or more, and still more preferably 10 times or more. In the case of using such thermally expandable microspheres, the adhesive force can be effectively reduced by heat treatment.

The content ratio of the thermally expandable microspheres in the pressure-sensitive adhesive layer can be appropriately set in accordance with the desired lowering property of adhesive force. The content ratio of the thermally 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 25 parts by weight, based on 100 parts by weight of the base polymer forming the pressure-sensitive adhesive layer. It is from parts by weight to 100 parts by weight.

When the pressure-sensitive adhesive layer includes thermally expandable microspheres, the arithmetic surface roughness Ra of the pressure-sensitive adhesive layer before the thermally expandable microspheres expand (ie, before heating) is preferably 500 nm or less, and more preferably 400 It is less than or equal to nm, more preferably less than or equal to 300 nm. Within such a range, a pressure-sensitive adhesive sheet having excellent adhesion to an adherend can be obtained. The pressure-sensitive adhesive layer having excellent surface smoothness can be obtained, for example, by making the thickness of the pressure-sensitive adhesive layer within the above range, or by applying and transferring the pressure-sensitive adhesive layer to a separator when a separate pressure-sensitive adhesive layer is provided. In addition, as described in the above section A, when the pressure-sensitive adhesive sheet of the present invention further includes a separate pressure-sensitive adhesive layer, the separate pressure-sensitive adhesive layer may contain thermally expandable microspheres. Even when the separate pressure-sensitive adhesive layer contains thermally expandable microspheres, the arithmetic surface roughness Ra of the pressure-sensitive adhesive layer is preferably within the above range.

When the pressure-sensitive adhesive layer contains heat-expandable microspheres, the pressure-sensitive adhesive layer is a base polymer having a dynamic storage modulus at 80°C in the range of 5 kPa to 1 MPa (more preferably 10 kPa to 0.8 MPa). It is preferable to include an adhesive to be constituted. If it is such a pressure-sensitive adhesive layer, it is possible to form a pressure-sensitive adhesive sheet that has an appropriate adhesiveness before heating and is easily reduced in adhesive strength by heating. In addition, the dynamic storage modulus can be measured under the measurement conditions of a frequency of 1 Hz and a temperature increase rate of 10°C/min using a dynamic viscoelasticity measuring device (for example, a brand name "ARES" manufactured by Rheometrics).

C. Base layer

In one embodiment, the adhesive sheet of this invention is equipped with the adhesive layer and a base material layer. 2A is a schematic cross-sectional view of an adhesive sheet according to an embodiment of the present invention. This pressure-sensitive adhesive sheet 100 includes a pressure-sensitive adhesive layer 10 and a base material layer 30 disposed on one side of the pressure-sensitive adhesive layer 10. 2B is a schematic cross-sectional view of an adhesive sheet according to another embodiment of the present invention. This pressure-sensitive adhesive sheet 200 includes an adhesive layer 10 and a base material layer 30, and the pressure-sensitive adhesive layers 10 are disposed on both sides of the base material layer 30. The two-layered pressure-sensitive adhesive layers may each be a pressure-sensitive adhesive layer having the same configuration or may be a pressure-sensitive adhesive layer having different configurations. Moreover, the structure may be provided in which the said adhesive layer is provided on one side of a base material layer, and another adhesive layer is provided on the other side.

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

The anchoring force can be measured as follows. The penetration force is (i) the entire surface of the adhesive sheet having a width of 20 mm x 150 mm in length opposite to the adhesive layer (for example, the outer surface of the base layer in the case of an adhesive sheet having a base layer/adhesive layer) A SUS plate is adhered to the surface through a predetermined double-sided tape, and (ii) an adhesive evaluation sheet containing a polyester resin having a size of 19 mm wide by 150 mm in length on the outer surface of the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet A sample for evaluation was prepared by attaching the adhesive surface of (a sheet having peeling adhesive strength of 10N/20mm to 20N/20mm with respect to polyethylene terephthalate, for example, Nitto Denko's brand name "No.315 tape"). , (iii) It is obtained by measuring the peel force between the base material layer and the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet by a tensile test. In addition, the above (i) to (iii) are performed under an environmental temperature of 23°C. The conditions of the tensile test when measuring the peel force were 50 mm/min of peeling rate and 180° of peeling angle.

As described above, the pressure-sensitive adhesive sheet having a high penetration power between the substrate layer and the pressure-sensitive adhesive layer is essentially a pressure-sensitive adhesive sheet in which the pressure-sensitive adhesive hardly remains, and if such a pressure-sensitive adhesive sheet is used, the effect of the present invention becomes remarkable. In the case of evaluation by the above method, it is more preferable that no peeling occurs at the interface between the substrate layer and the pressure-sensitive adhesive layer, and is, for example, a pressure-sensitive adhesive sheet that is peeled between the SUS plate and the substrate layer. A pressure-sensitive adhesive sheet having high penetration power can be obtained, for example, by using the rubber-based pressure-sensitive adhesive (Rub1) as the pressure-sensitive adhesive, or by adding an isocyanate-based crosslinking agent to the pressure-sensitive adhesive.

Examples of the substrate layer include a resin sheet, a nonwoven fabric, paper, a metal foil, a woven fabric, a rubber sheet, a foam sheet, and this laminate (in particular, a laminate including a resin sheet). Examples of the resin constituting the resin sheet include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate (PBT), polyethylene (PE), polypropylene (PP), and ethylene-propylene copolymer. , Ethylene-vinyl acetate copolymer (EVA), polyamide (nylon), wholly aromatic polyamide (aramid), polyimide (PI), polyvinyl chloride (PVC), polyphenylene sulfide (PPS), fluorine resin, poly Ether ether ketone (PEEK), etc. are mentioned. Examples of the nonwoven fabric include nonwoven fabrics made of natural fibers having heat resistance such as nonwoven fabrics containing manila hemp; And synthetic resin nonwoven fabrics such as polypropylene resin nonwoven fabric, polyethylene resin nonwoven fabric, and ester-based resin nonwoven fabric. As metal foil, copper foil, stainless steel foil, aluminum foil, etc. are mentioned. Japanese paper, kraft paper, etc. are mentioned as paper.

The thickness of the base layer may be set to any suitable thickness depending on the desired strength or flexibility, and purpose of use. The thickness of the substrate layer is preferably 1000 μm or less, more preferably 1 μm to 1000 μm, still more preferably 1 μm to 500 μm, particularly preferably 3 μm to 300 μm, and most preferably Is from 5 μm to 250 μm.

The substrate layer may be subjected to surface treatment. Examples of the surface treatment include corona treatment, chromic acid treatment, ozone exposure, flame exposure, high-pressure electric shock exposure, ionizing radiation treatment, and coating treatment with a primer.

Examples of the organic coating material include materials described in Plastic Hard Coating Materials II (CMC Publication, (2004)). Preferably, a urethane polymer, more preferably a polyacrylic urethane, a polyester urethane, or a precursor thereof is used. This is because coating and application to the substrate are easy, and industrially, a wide variety of materials can be selected and can be obtained at low cost. The urethane polymer is, for example, a polymer comprising a reaction mixture of an isocyanato monomer and an alcoholic hydroxyl group-containing monomer (eg, a hydroxyl group-containing acrylic compound or a hydroxyl group-containing ester compound). The organic coating material may contain, as an optional additive, a chain extender such as polyamine, an anti-aging agent, an oxidation stabilizer, and the like. The thickness of the organic coating layer is not particularly limited. 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. 3 is a schematic cross-sectional view of an adhesive sheet according to an embodiment of the present invention. The pressure-sensitive adhesive sheet 300 further includes an elastic layer 40. The elastic layer 40 may be preferably disposed when the pressure-sensitive adhesive layer 10 includes the thermally expandable microspheres. In addition, when the pressure-sensitive adhesive sheet 300 includes the base layer 30, the elastic layer 40 may be disposed between the pressure-sensitive adhesive layer 10 and the base layer 30 as shown in the illustrated example, and the base material It may be provided on the side opposite to the adhesive layer of the layer. The elastic layer 40 may be provided in two or more layers. In addition, FIG. 3 shows an example in which one elastic layer 40 is provided and the elastic layer 40 is disposed between the pressure-sensitive adhesive layer 10 and the base layer 30. By providing the elastic layer 40, the followability to the adherend is improved. In addition, 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 plane direction is restrained, and the deformation in the thickness direction is given priority. As a result, peelability is improved.

The elastic layer contains a base polymer, and as the base polymer, a polymer exemplified as a base polymer constituting the pressure-sensitive adhesive layer can be used. Further, the elastic layer may contain natural rubber, synthetic rubber, synthetic resin, or the like. Examples of the synthetic rubber and synthetic resin include nitrile-based, diene-based and acrylic synthetic rubbers; Thermoplastic elastomers such as polyolefin-based and polyester-based; Ethylene-vinyl acetate copolymer; Polyurethane; Polybutadiene; And soft polyvinyl chloride. The base polymer constituting the elastic layer may be the same as or different from the base polymer constituting the pressure-sensitive adhesive layer. The elastic layer may be a foamed film formed of the base polymer. The foamed film can be obtained by any suitable method. In addition, the elastic layer and the pressure-sensitive adhesive layer can be distinguished by the difference of the base polymer and/or the presence or absence of thermally expandable microspheres (the elastic layer does not contain thermally expandable microspheres).

The elastic layer, if necessary, may contain any suitable additive. As said additive, a crosslinking agent, a vulcanizing agent, a tackifier, a plasticizer, a softener, a filler, an aging preventive agent, etc. are mentioned, for example. 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 function of the elastic layer can be sufficiently exhibited.

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

E. Separator

The pressure-sensitive adhesive sheet of the present invention can further include a separator as necessary. At least one surface of the separator is a release surface, and may be provided to protect the pressure-sensitive adhesive layer. The separator can be made of any suitable material.

F. Manufacturing method of adhesive sheet

The pressure-sensitive 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 applying a composition containing a pressure-sensitive adhesive onto a substrate layer (in the case of obtaining a pressure-sensitive adhesive sheet not including the substrate layer, any suitable substrate) or any suitable substrate And a method of transferring a coating layer formed by coating a composition containing an adhesive on the substrate layer. The composition containing the pressure-sensitive adhesive may contain any suitable solvent.

In the case of forming the pressure-sensitive adhesive layer including thermally expandable microspheres, a composition including the thermally expandable microspheres, an adhesive, and any suitable solvent may be applied to the substrate layer to form the pressure-sensitive adhesive layer. Alternatively, after sprinkling thermally expandable microspheres on the pressure-sensitive adhesive coating layer, the thermally expandable microspheres may be embedded in the pressure-sensitive adhesive using a laminator or the like to form a pressure-sensitive adhesive layer containing thermally expandable microspheres.

When the pressure-sensitive adhesive layer has the elastic layer, the elastic layer may be formed by applying a composition for forming an elastic layer, for example, on the base layer or the pressure-sensitive adhesive layer.

As the application method of the pressure-sensitive adhesive and each composition, any suitable application method may be employed. For example, each layer can be formed by drying after application. As the coating method, for example, a coating method using a multi coater, a die coater, a gravure coater, an applicator or the like can be mentioned. As a drying method, natural drying, heat drying, etc. are mentioned, for example. In the case of heating and drying, the heating temperature may be set to any suitable temperature according to the characteristics of the material to be dried.

[Example]

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

(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 to 4-tert-butylphenylglycidyl ether was measured.

On the surface of the pressure-sensitive adhesive layer, 2 μl of 4-tert-butylphenylglycidyl ether was added dropwise to measure the contact angle after 5 seconds (N=5). The measurement of the contact angle was performed in an atmosphere of 23°C and 50% RH using a contact angle meter (manufactured by Kyohwa Gaimen, brand name “CX-A type”).

(2) sp value

The sp value of the polymer in the pressure-sensitive adhesive layer after formation of the pressure-sensitive adhesive sheet was determined by Fedors' method (by Hideki Yamamoto, ``sp value basics, application and calculation method,'' published by Joho Kiko, Inc., published on April 3, 2006). , Pages 66 to 67). Specifically, the sp value is the evaporation energy Δe (cal) of each atom or group forming the polymer at 25°C, and the molar volume ΔV (cm 3) of each atom or group forming the polymer at 25°C. ), it was calculated by the following equation.

Sp value = (ΣΔe/ΣΔV) ^1/2

In addition, when the polymer is a copolymer, the SP value is obtained by calculating the SP value of each homopolymer of each structural unit constituting the copolymer, and multiplying each of these SP values by the molar fraction of each structural unit. It is calculated by adding up.

In the above case, the analysis method of each constituent unit (analysis of the composition of the polymer) is to appropriately collect only the adhesive layer from the adhesive sheet, and immerse it in an organic solvent such as dimethylformamide (DMF), acetone, methanol, tetrahydrofuran (THF), etc. The resulting solvent-soluble portion is recovered, and can be determined from a gel filtration permeation chromatography (GPC), nuclear magnetic resonance spectroscopy (NMR), infrared spectroscopy (IR), and an analysis method of mass spectrometry.

(3) adhesion

Through a double-sided adhesive tape (manufactured by Nitto Denko, brand name "No.531") on the entire surface of the pressure-sensitive adhesive sheet (20 mm in width x 140 mm in length) opposite to the pressure-sensitive adhesive layer, a SUS304 plate was placed on a 2 kg hand roller. It adhered using.

Subsequently, a polyethylene terephthalate film (manufactured by Toray Corporation, brand name "Lumor S-10", thickness: 25 µm, width: 30 mm) was adhered to the entire surface of the pressure-sensitive adhesive layer (temperature: 23°C, humidity: 65 %, 2kg roller 1 round trip).

The sample for evaluation obtained as described above was subjected to a tensile test. As the tensile tester, the brand name "Shimazu Autograph AG-120kN" manufactured by Shimadzu Corporation was used. After setting the sample for evaluation in a tensile testing machine, after leaving for 30 minutes at 23 degreeC environmental temperature, a tensile test was started. The conditions of the tensile test were peeling angle: 180°, and peeling rate (tensile speed): 300 mm/min. The load when peeling the adhesive sheet 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 power

A SUS304 plate (width 40 mm wide) through a double-sided adhesive tape (Nitto Denko Co., Ltd., brand name “No.531”) is interposed on the entire surface of the side opposite to the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet (20 mm in width x 140 mm in length). X 120 mm in length) was adhered using a 2 kg hand roller.

Subsequently, an evaluation sheet (Nitto Denko Co., Ltd., brand name "No.315 tape", width 19 mm x length 150 mm) was adhered (temperature: 23°C, humidity: 65%, 2 kg roller 1 round trip).

The sample for evaluation obtained as described above was subjected to a tensile test. As a tensile tester, a brand name "Shimazu Autograph AG-120kN" manufactured by Shimadzu Seisakusho was used. The conditions of the tensile test were peeling angle: 180°, and peeling rate (tensile speed): 50 mm/min. The evaluation sheet was held and the load when the pressure-sensitive adhesive layer was to be peeled off from the substrate layer of the pressure-sensitive adhesive sheet was measured, and the maximum load at that time was taken as the penetration force between the substrate layer and the pressure-sensitive adhesive layer.

(5) Tag value

Through a double-sided adhesive tape (Nitto Denko Co., Ltd., brand name "No.531") on the entire surface opposite to the adhesive layer of the adhesive sheet (20 mm in width x 50 mm in length), slide glass (Matsunami Glass). Industrial company make, 26 mm x 76 mm) was bonded using a 2 kg hand roller.

The probe tag value on the outer surface of the pressure-sensitive adhesive layer in the sample for evaluation obtained as described above was measured using a probe tag measuring device (manufactured by RHESCA, brand name "TACKINESS Model TAC-II"). Measurement conditions are probe processing speed (Immersion speed): 30 mm/min, test speed (test speed): 30 mm/min, adhesion load: 100 gf, adhesion holding time (press time): 1 second, probe area (Probe Area): It was set as 5 mm phi SUS.

(6) Holding power test

Under an environmental temperature of 23°C, the entire outer surface of the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet (10 mm wide x 150 mm long) was coated with a Bakelite plate (manufactured by Futamura Chemical Co., brand name “Daiko Light FL-102”, 25 mm wide. It adhered to the center part of length 125 mm x thickness 2 mm) using a 2 kg hand roller.

After aging the sample for evaluation obtained as described above for 30 minutes at an environmental temperature of 40°C, a tape creep tester (manufactured by Imada Seisakusho, model/model number “12 stations central type/041”) Using, a load of 1.96 N was applied, the state was maintained, and left for 2 hours.

The movement distance (difference) of the pressure-sensitive adhesive sheet by pressing was measured based on the position on the bakelite plate before pressing. The shorter the moving distance is, the higher the holding power is.

(7) Surface roughness

The arithmetic surface roughness Ra of the surface of the adhesive layer of the adhesive sheet was measured according to JIS B0601. An optical surface roughness meter (manufactured by Veeco Metrogy Group, brand name "Wyko NT9100") was used for the measuring device.

(8) standoff suppression effect

Naphthalene-type bifunctional epoxy resin (manufactured by DIC, brand name ``HP4032D'', epoxy equivalent: 144) 100 parts by weight, phenoxy resin (manufactured by Mitsui Chemical, brand name ``EP4250'') 40 parts by weight, and phenol resin (Meiwa Gase) Director made, brand name "MEH-8000") 129 parts by weight, spherical silica (made by Admatex, brand name "SO-25R") 1137 parts by weight, dye (made by Orient Chemical Co., Ltd., brand name "OIL BLACK BS") 14 parts by weight, 1 part by weight of a curing catalyst (manufactured by Shikoku Chemicals, brand name "2PHZ-PW") and 30 parts by weight of methyl ethyl ketone were mixed to prepare a resin solution A (solid content concentration: 23.6% by weight).

On the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet, a Si wafer (1 cm × 1 cm, thickness 500 μm) was placed, and the Si wafer was covered and sealed on the pressure-sensitive adhesive layer, and the resin solution A was applied, Size: 3 cm x 3 cm), the resin solution was cured by heating at 170°C for 10 minutes, and a structure made of a Si wafer and a sealing resin was formed on the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet.

After cooling, the adhesive sheet was peeled off from the structure. With respect to the adhesive sheet after peeling, the difference between the thickness of the pressure-sensitive adhesive layer at the portion not in contact with the Si wafer and the thickness of the pressure-sensitive adhesive layer at the portion in contact with the Si wafer was taken as the standoff amount.

(9) adhesive persistence

In the same manner as in (8) above, a structure made 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 from the structure. After peeling, the adhesive surface of the structure was observed under a microscope (manufactured by Keyence Corporation, brand name "VHX-100", magnification: 150 times), and the presence or absence of the adhesive layer component as it was attached to the structure was confirmed. In Table 1, when there are less than 5 adherends having a particle diameter of 100 µm (in the case of an irregular shape, the length of the longest side is 100 µm) or more,?

[Example 1]

100 parts by weight of an acrylic copolymer as a base polymer (a copolymer of 2ethylhexyl acrylate and hydroxyethyl acrylate, a constitutional unit of 2ethylhexyl acrylate: a constitutional unit of hydroxyethyl acrylate = 100:5 (weight ratio)), and an isocyanate type 1.5 parts by weight of a crosslinking agent (manufactured by Nippon Polyurethane, brand name ``Coronate L'', 10 parts by weight of terpenephenol tackifying resin (manufactured by Yasuhara Chemical, brand name ``YS Polyster S145'') and 100 parts by weight of toluene are mixed, A composition for forming an adhesive layer was prepared.

The composition for forming the pressure-sensitive adhesive layer was applied to one side of a polytetrafluoroethylene film (manufactured by Toray, brand name “Lumor S10”, thickness 38 μm) as a base layer, and formed into a base layer and an adhesive layer (thickness 10 μm). A constitutive adhesive sheet was obtained.

[Example 2]

Acrylic copolymer as a base polymer (copolymer of acrylic acid 2ethylhexyl and acrylic acid and trimethylolpropane acrylate, acrylic acid 2ethylhexyl structural unit: acrylic acid structural unit: trimethylolpropane acrylate structural unit = 100:3:0.03 (weight ratio) )) 100 parts by weight, 0.5 parts by weight of an epoxy crosslinking agent (manufactured by Mitsubishi Gas Chemical Co., Ltd., brand name ``Tetrad C''), and a terpenephenol-based tackifying resin (manufactured by Yasuhara Chemical Co., Ltd., brand name ``YS Polyster S145'') 10 A composition for forming an adhesive layer was prepared by mixing parts by weight and 100 parts by weight of toluene.

The composition for forming the pressure-sensitive adhesive layer was applied to one side of a polytetrafluoroethylene film (manufactured by Toray, brand name “Lumor S10”, thickness 38 μm) as a base layer, and formed into a base layer and an adhesive layer (thickness 10 μm). A constitutive adhesive sheet was obtained.

[Example 3]

100 parts by weight of addition reaction type silicone adhesive (manufactured by Toray, brand name ``silicone rubber SD-4580L'', silicone rubber: silicone resin = 60:40 (weight ratio)), and platinum catalyst (manufactured by Toray, brand 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 pressure-sensitive adhesive layer-forming composition is applied on one side of a polyimide film (manufactured by Toray DuPont, brand name "Kapton 200H", thickness 50 μm) as a base layer, and is composed of a base layer and an adhesive layer (10 μm) Got it.

[Example 4]

100 parts by weight of polyisobutylene rubber (manufactured by BASF Japan, brand name ``Opanol B80''), 1.5 parts by weight of hydroxyl group-containing polyolefin (manufactured by Idemitsu Kosan, brand name ``Epol''), and isocyanate-based crosslinking agent (manufactured by Nippon Polyurethane Kogyo Corporation) , Brand name "Coronate L") 4 parts by weight and 200 parts by weight of toluene were mixed to prepare a composition for forming an adhesive layer.

The composition for forming a pressure-sensitive adhesive was applied on one side of a polytetrafluoroethylene film (manufactured by Toray, brand name “Lumor S10”, thickness 38 μm) as a substrate layer, and composed of a substrate layer and an adhesive layer (thickness 10 μm). The resulting adhesive sheet was obtained.

[Example 5]

To the composition for forming the pressure-sensitive adhesive layer, 30 parts by weight of thermally expandable microspheres (manufactured by Matsumoto Yushi Seiyaku, brand name "Matsumoto Micro Spare F-50") were further added, except that the thickness of the pressure-sensitive adhesive layer was set to 40 μm. It carried out similarly to Example 1, and obtained the adhesive sheet.

[Example 6]

To the composition for forming the pressure-sensitive adhesive layer, 30 parts by weight of thermally expandable microspheres (manufactured by Matsumoto Yushi Seiyaku, brand name "Matsumoto Micro Spare F-50") were further added, except that the thickness of the pressure-sensitive adhesive layer was set to 40 μm. It carried out similarly to Example 2, and obtained the adhesive sheet.

[Example 7]

To the composition for forming the pressure-sensitive adhesive layer, 30 parts by weight of thermally expandable microspheres (manufactured by Matsumoto Yushi Seiyaku, brand name "Matsumoto Micro Spare F-50") were further added, except that the thickness of the pressure-sensitive adhesive layer was set to 40 μm. It carried out similarly to Example 3, and obtained the adhesive sheet.

[Example 8]

To the composition for forming the pressure-sensitive adhesive layer, 30 parts by weight of thermally expandable microspheres (manufactured by Matsumoto Yushi Seiyaku, brand name "Matsumoto Micro Spare F-50") were further added, except that the thickness of the pressure-sensitive adhesive layer was set to 40 μm. It carried out similarly to Example 4, and obtained the adhesive sheet.

[Example 9]

In the same manner as in Example 1, a composition for forming an adhesive layer was prepared.

Acrylic copolymer (copolymer of ethyl acrylate, 2ethylhexyl acrylate, and hydroxyethyl acrylate, ethyl acrylate structural unit: 2ethylhexyl acrylate structural unit: hydroxyethyl acrylate structural unit: 70:30:5:6 ( Weight ratio)) 100 parts by weight, 2 parts by weight of an isocyanate crosslinking agent (manufactured by Nippon Polyurethane Co., Ltd., brand name "Coronate L"), and 100 parts by weight of toluene were mixed to prepare a composition for forming an elastic layer.

Acrylic copolymer (copolymer of ethyl acrylate, 2ethylhexyl acrylate, and hydroxyethyl acrylate, ethyl acrylate structural unit: 2ethylhexyl acrylate structural unit: hydroxyethyl acrylate structural unit: 70:30:5:6 ( Weight ratio)) 100 parts by weight, 2 parts by weight of an isocyanate crosslinking agent (manufactured by Nippon Polyurethane Kogyo, brand name ``Coronate L''), and a rosin phenolic tackifying resin (manufactured by Sumitomo Bakelite, brand name ``Sumiride resin PR-12603 '') 15 parts by weight, and 35 parts by weight of thermally expandable microspheres (manufactured by Matsumoto Yushi Seiyaku, brand name ``Matsumoto Micro Spare F-50''), mixed with 100 parts by weight of toluene, and a composition for forming a separate adhesive layer Was prepared.

The composition for forming the pressure-sensitive adhesive layer was applied to one side of a PET film (manufactured by Toray Corporation, brand name "Lumor S10", thickness 38 µm) as a base layer to form a pressure-sensitive adhesive layer (thickness 10 µm) on the base layer. Further, a composition for forming an elastic layer was applied to the other side of the PET film to form an elastic layer (10 μm in thickness) on the base layer.

Separately, another pressure-sensitive adhesive layer (thickness 35 μm) was formed by applying the composition for forming another pressure-sensitive adhesive layer on another PET film. The other pressure-sensitive adhesive layer was transferred onto the elastic layer to obtain a pressure-sensitive adhesive sheet including a pressure-sensitive adhesive layer/substrate layer/elastic layer/other pressure-sensitive adhesive layer.

[Example 10]

As a composition for forming an adhesive layer, except having used the composition for forming an adhesive layer obtained in Example 2, it carried out similarly to Example 9, and obtained the adhesive sheet.

[Example 11]

As the composition for forming an adhesive layer, except having used the composition for forming an adhesive layer obtained in Example 3, it carried out similarly to Example 9, and obtained the adhesive sheet.

[Example 12]

As the composition for forming an adhesive layer, except having used the composition for forming an adhesive layer obtained in Example 4, it carried out similarly to Example 9, and obtained the adhesive sheet.

[Comparative Example 1]

100 parts by weight of an acrylic copolymer (a copolymer of methyl acrylate and 2ethylhexyl acrylate and acrylic acid, methyl acrylate structural unit: 2ethylhexyl acrylate structural unit: acrylic acid structural unit = 15:85:8 (weight ratio)), and epoxy-based Mixing 3 parts by weight of a crosslinking agent (manufactured by Mitsubishi Gas Chemical Co., Ltd., brand name "Tetrad C"), 10 parts by weight of terpenephenol tackifier resin (manufactured by Yasuhara Chemical, brand name "YS Polyster S145") and 100 parts by weight of toluene Then, a composition for forming an adhesive layer was prepared.

The composition for forming the pressure-sensitive adhesive layer was applied to one side of a polytetrafluoroethylene film (manufactured by Toray, brand name “Lumor S10”, thickness 38 μm) as a base layer, and formed into a base layer and an adhesive layer (thickness 10 μm). A constitutive adhesive sheet was obtained.

As apparent 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-tert-butylphenylglycidyl ether, that is, a pressure-sensitive adhesive having low affinity for a sealing resin. By providing a layer, it is possible to obtain a pressure-sensitive adhesive sheet with less occurrence of stand-off and less likely to cause residual pressure-sensitive adhesive.

10 adhesive layer
30 base layer
40 elastic layer
100, 200, 300 adhesive sheet

Claims (12)

A pressure-sensitive adhesive sheet comprising a substrate layer, a pressure-sensitive adhesive layer disposed on one side of the substrate layer, and a pressure-sensitive adhesive layer or a separate pressure-sensitive adhesive layer disposed on the other side of the substrate layer,
The pressure-sensitive adhesive layer includes an acrylic pressure-sensitive adhesive and thermally expandable microspheres,
The acrylic pressure-sensitive adhesive includes, 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 to 4-tert-butylphenyl glycidyl ether is 15° or more,
The adhesion of the pressure-sensitive adhesive sheet to polyethylene terephthalate at 23° C. is 0.5 N/20 mm or more,
In a wafer level package, an adhesive sheet used as a temporary fixing material when sealing a plurality of semiconductor chips collectively with a sealing resin. The method of claim 1,
The pressure-sensitive adhesive sheet, 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 method according to claim 1 or 2,
The pressure-sensitive adhesive sheet, wherein the pressure-sensitive adhesive layer has a probe tag value of 50 N/5 mmφ or more. The method according to claim 1 or 2,
The acrylic pressure-sensitive adhesive includes an acrylic polymer having an alkyl ester having 6 or more carbon atoms in the side chain as a base polymer,
In the acrylic polymer, the content ratio of the constitutional 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 constitutional units constituting the acrylic polymer. The method according to claim 1 or 2,
The adhesive sheet, wherein the acrylic polymer contains a structural unit derived from a hydroxyl group-containing monomer. The method of claim 5,
The pressure-sensitive adhesive sheet, 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 method of claim 6,
The pressure-sensitive adhesive sheet, wherein the arithmetic surface roughness Ra of the pressure-sensitive adhesive layer before heating the thermally expandable microspheres is more than 0 nm and not more than 500 nm. The method according to claim 1 or 2,
Under an environmental temperature of 23°C, the entire outer surface of the pressure-sensitive adhesive layer was bonded to a bakelite plate, aged for 30 minutes under an environmental temperature of 40°C, and then maintained for 2 hours while applying a load of 1.96N, the baking The pressure-sensitive adhesive sheet in which the deviation with respect to the light plate is more than 0 mm and 0.5 mm or less. The method according to claim 1 or 2,
The pressure-sensitive adhesive sheet, wherein the anchoring force of the substrate layer and the pressure-sensitive adhesive layer is 6.0 N/19 mm or more. The method according to claim 1 or 2,
An adhesive sheet further comprising an elastic layer. The method of claim 10,
The pressure-sensitive adhesive sheet, wherein the elastic layer is disposed between the pressure-sensitive adhesive layer and the base material layer. The method of claim 10,
The pressure-sensitive adhesive sheet, wherein the elastic layer has a tensile modulus of elasticity of less than 100 MPa at 25°C.

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