Adhesive tape

Abstract

The invention relates to an adhesive tape. The present invention provides an adhesive tape which suppresses surface contamination of an adherend caused by foreign matter and has excellent antistatic performance. An adhesive tape according to an embodiment of the present invention is provided with a substrate and an adhesive layer, the adhesive layer being formed from an active energy ray-curable adhesive containing a (meth) acrylic polymer having a radiation-polymerizable carbon-carbon double bond, an ionic liquid, and a photopolymerization initiator.

Description

TECHNICAL FIELD

[0001] The present application relates to an adhesive tape. BACKGROUND

[0002] In recent years, the circuit surface of a semiconductor is being developed toward narrow width and three-dimensionality of the circuit width, resulting in a more complex and delicate circuit. As a method of three-dimensionality of a semiconductor, direct bonding (hybrid bonding) in which wafers are directly bonded to each other is being studied (Patent Literature 1). In addition, optical members forming an optical part of a camera lens such as a CMOS (Complementary Metal Oxide Semiconductor) image sensor, an infrared cut filter, and the like are being high-functionalized, and fine adherents such as dust can become a cause of functional reduction. Therefore, the optical member forming the optical lens for the camera can be stored in a state in which a protective adhesive tape is attached to the surface until it is used.

[0003] PRIOR ART DOCUMENT

[0004] PATENT LITERATURE

[0005] Patent Literature 1: Japanese Patent Application Laid-Open No. 2007-180273

[0006] Patent Literature 2: Japanese Patent No. 5773379 SUMMARY

[0007] PROBLEMS TO BE SOLVED BY THE INVENTION

[0008] In the case of performing direct bonding, in order to suppress occurrence of defects, it is required that the surface of the wafer to be bonded is less contaminated. The wafer surface is usually bonded with an adhesive tape for the purpose of protecting the circuit surface during the period until bonding. However, even in the case where the adhesive tape is bonded, sometimes foreign matter adheres to the circuit surface after the adhesive tape is peeled off, and a cleaning process is also required. Depending on the kind and size of the foreign matter, sometimes it cannot be sufficiently removed even in the case where the cleaning process is performed. In addition, the delicate and complex circuit surface sometimes suffers from electrostatic destruction at the time of peeling of the adhesive tape. Therefore, an adhesive tape excellent in antistatic property is required. However, in the case where an antistatic agent is used, sometimes contamination of the adherend caused by the antistatic agent occurs. Therefore, an adhesive tape in which surface contamination of the adherend caused by foreign matter is suppressed and which is also excellent in antistatic property is required.

[0009] Even in a laminated CMOS image sensor (for example, Patent Literature 2), foreign matter can adhere to the surface on which the adhesive tape is attached when the adhesive tape for surface protection is peeled off, and thus a cleaning process can be required after that. An infrared cut filter can also be shipped in a state of being disposed on the adhesive tape. Since the product after shipment is in the hands of the purchaser, it is difficult to clean after peeling off the adhesive tape. Therefore, the size of the adhered foreign matter allowed after peeling off the adhesive tape has been decreasing year by year, and an adhesive tape that further suppresses surface contamination of the adherend by foreign matter is required. In addition, depending on the components used in the optical member, the adhesive tape can be required to have excellent antistatic properties.

[0010] Means for solving the problem

[0011] 1. The adhesive tape of the embodiment of the present application comprises a substrate and an adhesive layer, the adhesive layer being formed of a active energy ray-curable adhesive, the active energy ray-curable adhesive comprising a (meth)acrylic polymer having a radiation-polymerizable carbon-carbon double bond, an ionic liquid, and a photopolymerization initiator.

[0012] 2. The adhesive tape according to the above 1, wherein a gel fraction after active energy ray irradiation of the active energy ray-curable adhesive can be 97.5% or more.

[0013] 3. The adhesive tape according to the above 1 or 2, wherein a cation of the ionic liquid can have an amino group.

[0014] 4. The adhesive tape according to any one of the above 1 to 3, wherein an anion of the ionic liquid can be a sulfonic acid group.

[0015] 5. The adhesive tape according to any one of the above 1 to 4, wherein a surface resistivity of the adhesive layer before active energy ray irradiation can be 5 x 10 11 Ω / □ or less.

[0016] 6. The adhesive tape according to any one of the above 1 to 5, wherein the active energy ray-curable adhesive can further comprise a polyalkylene glycol.

[0017] 7. The adhesive tape according to the above 6, wherein the polyalkylene glycol can be at least one selected from the group consisting of polyethylene glycol and polypropylene glycol.

[0018] 8. The adhesive tape according to any one of the above 1 to 7, wherein a transmittance of light of a wavelength of 365 nm of the substrate can be 60% or more.

[0019] 9. The adhesive tape according to any one of 1 to 8 above, wherein the extinction coefficient of the photopolymerization initiator in methanol at a wavelength of 365 nm can be 80 ml / g·cm or higher.

[0020] 10. The adhesive tape according to any one of 1 to 9 above, wherein the content of the photopolymerization initiator may be 0.5 parts by weight or less relative to 100 parts by weight of the above (meth)acrylic polymer.

[0021] 11. The adhesive tape according to any one of 1 to 10 above, wherein the substrate may be a polyethylene terephthalate film.

[0022] 12. The adhesive tape according to any one of 1 to 11 above, wherein a release liner having a light release layer may be further laminated on the adhesive layer, the thickness of which may be 0.06 μm or less.

[0023] 13. The adhesive tape according to 12 above, wherein the Si content on the surface of the adhesive layer after the release liner has been peeled off can be less than 1.0 atomic%.

[0024] 14. The adhesive tape according to any one of 1 to 13 above, wherein the number of particles larger than 0.30 μm in the adhesive tape peel evaluation may be 50 or less.

[0025] 15. The adhesive tape according to any one of 1 to 14 above, wherein the number of particles of greater than or equal to 0.15 μm and less than 0.30 μm in the tape peel evaluation of the adhesive tape may be less than 1500.

[0026] 16. The adhesive tape according to any one of 1 to 15 above, wherein the adhesive tape can be used for circuit surface protection of a semiconductor wafer.

[0027] 17. The adhesive tape according to any one of 1 to 15 above, wherein the adhesive tape can be used for surface protection of optical articles and optical glass articles.

[0028] Invention Effects

[0029] According to embodiments of the present invention, an adhesive tape that suppresses surface contamination of the adhered material caused by foreign matter and also has excellent antistatic properties can be provided. Attached Figure Description

[0030] Figure 1 This is a cross-sectional schematic diagram of the adhesive tape according to an embodiment of the present invention.

[0031] Label Explanation

[0032] 10 substrate

[0033] 20 adhesive layer

[0034] 100 adhesive tape DETAILED DESCRIPTION

[0035] A. Overall structure of adhesive tape

[0036] The adhesive tape of the embodiment of the present application is provided with a substrate and an adhesive layer, the adhesive layer being formed of a active energy ray-curable adhesive containing a (meth)acrylic polymer having a radiation-polymerizable carbon-carbon double bond (hereinafter, also referred to as an acrylic polymer having a radiation-polymerizable carbon-carbon double bond), an ionic liquid, and a photopolymerization initiator. Figure 1 is a cross-sectional schematic view of the adhesive tape of the embodiment of the present application. The adhesive tape 100 of the embodiment of the present application is provided with a substrate 10 and an adhesive layer 20. Practically, during a period until use, a release liner can be temporarily attached peelably on the adhesive layer 20. The adhesive layer 20 is formed of an active energy ray-curable adhesive containing a (meth)acrylic polymer having a radiation-polymerizable carbon-carbon double bond, an ionic liquid, and a photopolymerization initiator. If the adhesive layer is formed of such an active energy ray-curable adhesive, surface contamination due to attachment of foreign matter on the surface of an adherend can be suppressed. As the foreign matter, not only dust and the like from the outside is considered, but also components from the adhesive constituting the adhesive layer are considered. As the active energy ray-curable adhesive, an adhesive in which a base polymer is a polymer having a radiation-polymerizable carbon-carbon double bond which can be cured by irradiation of active energy rays, and an adhesive in which an oligomer and the like having active energy ray-curing property is used are typically exemplified. In the case where a polymer having a radiation-polymerizable carbon-carbon double bond is used, it is considered that attachment of foreign matter on an adherend is reduced because the molecular weight of the polymer becomes large. However, in fact, even in the case where an adhesive containing a polymer having a radiation-polymerizable carbon-carbon double bond is used, contamination of an adherend from the adhesive layer can occur. In the adhesive tape of the embodiment of the present application, the active energy ray-curable adhesive constituting the adhesive layer contains an ionic liquid. If the ionic liquid is contained, attachment of foreign matter from the adhesive constituting the adhesive layer on the surface of an adherend can be further suppressed. In addition, the ionic liquid also functions as an antistatic component, and the antistatic function of the adhesive tape can be improved. Note that "(meth)acrylic acid" means acrylic acid and / or methacrylic acid.

[0037] The number of particles of 0.30 μm or more in the adhesive tape of the embodiment of the present application in the tape peeling evaluation is preferably 50 or less, more preferably 45 or less, and further preferably 35 or less. The number of particles of 0.30 μm or more is more preferably smaller, and can be 0. The particles of 0.30 μm or more can be a cause of defects in the use of optical systems. As the particles of 0.30 μm or more, for example, there can be mentioned a block-like substance from the adhesive. In addition, the number of particles of 0.15 μm or more and less than 0.30 μm in the tape peeling evaluation is preferably 1500 or less, more preferably 1400 or less, and further preferably 1000 or less. The number of particles of 0.15 μm or more and less than 0.30 μm is more preferably smaller, and can be 0. 0.15 μm can be the smallest size that can be measured by a general particle measuring device. If the number of particles of 0.30 μm or more and / or the number of particles of 0.15 μm or more is within the above range, an adhesive tape that suppresses the adhesion of foreign matter to an adherend and the surface contamination of the adherend caused by foreign matter can be obtained. In the present specification, the tape peeling evaluation refers to the number of particles on the wafer surface measured by the following evaluation method.

[0038] <the tape peeling evaluation>

[0039] The adhesive tape was cut into 25 cm x 25 cm to prepare a test sample. The test sample was attached to a 6-inch mirror wafer. Then, the test sample was left at 23°C for 2 hours. Subsequently, the test sample was irradiated with active energy rays (ultraviolet rays) using a cutting process UV irradiation device (for example, manufactured by Sibata Scientific Technology Ltd., product name UM-810). The active energy rays were irradiated in such a manner that the cumulative light quantity was 460 mJ / cm2in the case where the extinction coefficient at a wavelength of 365 nm in methanol of the photopolymerization initiator contained in the adhesive layer was 80 ml / g-cm or more, and the cumulative light quantity was 700 mJ / cm2in the case where the extinction coefficient at a wavelength of 365 nm in methanol of the photopolymerization initiator was less than 80 ml / g-cm. Then, the adhesive tape was peeled from the wafer surface, and the number of particles on the wafer surface was measured using a wafer surface inspection device (for example, manufactured by TAKANO Corporation, product name "WM-7S"). 2 2 The extinction coefficient at a wavelength of 365 nm in methanol of the photopolymerization initiator will be described later.

[0040] ​The adhesive tape can further include any appropriate layer other than the base material and the adhesive layer. For example, an intermediate layer, an antistatic layer can be further included. If the intermediate layer is provided, the adhesion to an adherend having a large unevenness on the surface can be improved. The intermediate layer can be formed of any appropriate material. It can be formed of a resin such as an ethylene-vinyl acetate resin, or it can be formed by irradiating ultraviolet rays to a ultraviolet-curable acrylic resin to cure it, or it can be formed using a composition including an acrylic resin and a ultraviolet-curable oligomer. If the composition including an acrylic resin and a ultraviolet-curable oligomer is used, the height difference of the surface of the adherend can be further absorbed at the time of bonding. In addition, the intermediate layer can be formed using any appropriate adhesive (an adhesive not having ultraviolet-curing property). If the antistatic layer is provided, the electrostatic destruction of the semiconductor element caused by static electricity at the time of peeling of the adhesive tape can be further prevented.

[0041] The thickness of the adhesive tape can be set within any appropriate range. It is preferably 10 μm to 500 μm, more preferably 50 μm to 400 μm, and further preferably 60 μm to 300 μm.

[0042] B. Base Material

[0043] The base material can be composed of any appropriate resin. As specific examples of the resin constituting the base material, there can be mentioned: polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate (PBT), polybutylene naphthalate (PBN), and the like polyester resins, ethylene-vinyl acetate copolymer, ethylene-methyl methacrylate copolymer, polyethylene, polypropylene, ethylene-propylene copolymer, and the like polyolefin resins, polyvinyl alcohol, polyvinylidene chloride, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, polyamide, polyimide, cellulose, fluorine-containing resin, polyether, polystyrene, and the like polystyrene resins, polycarbonate, polyethersulfone, and the like. It is preferable to use polyethylene terephthalate, ethylene-vinyl acetate copolymer, polyolefin resins, and laminated films thereof. In the case of using a laminated film, the films formed of these resins can be laminated in any appropriate order and number. If these resins are used, an adhesive tape suitable for the process of backgrinding, dicing, and the like can be obtained. In addition, if there is no problem in the use, a soft base material such as ethylene-vinyl acetate copolymer, polyolefin resins, and the like can be used, and in this case, the stress at the time of peeling can be dispersed. As a result, the occurrence of cohesive failure of the adhesive layer can be suppressed, and the number of foreign matters generated can be suppressed.

[0044] The base material can further include other components within a range not impairing the effects of the present application. As the other components, for example, there can be mentioned: antioxidants, ultraviolet absorbers, light stabilizers, heat-resistant stabilizers, and the like. The kind and the amount of use of the other components can be used in any appropriate amount according to the purpose.

[0045] The light transmittance of the substrate for light having a wavelength of 365 nm is preferably 60% or greater, and more preferably 70% or greater. If the light transmittance for light having a wavelength of 365 nm is within the above range, it is possible to achieve both the visual recognition of the adhesive tape in a state of being attached to an adherend and the light peeling of the adhesive layer by irradiation with active energy rays. If the light transmittance for light having a wavelength of 365 nm is less than 60%, the visual recognition is improved, but the adhesive layer can not be sufficiently cured.

[0046] The light transmittance of the substrate for light having a wavelength of 365 nm can be adjusted by any appropriate method. For example, the light transmittance can be adjusted by adding any appropriate material such as a colorant to the material constituting the substrate, or by providing a colored layer on any appropriate surface of the substrate. As the colorant, any appropriate colorant can be used. For example, pigments such as phthalocyanine-based pigments can be listed. The colorant can be used alone or in combination with two or more. In addition, the visual recognition can be improved by reducing the transparency by providing a matte finish or the like concave-convex on one surface of the substrate (the surface on the side on which the adhesive layer of the adhesive tape to be obtained is not laminated).

[0047] The substrate can further have any appropriate other layer. Specifically, an easy-adhesive layer, an antistatic layer, or the like can be listed. The easy-adhesive layer and the antistatic layer can contain any appropriate anti-blocking agent. In the case where the light transmittance of the substrate for light having a wavelength of 365 nm is adjusted to 60% or greater, the light transmittance can also be adjusted by adding a colorant or the like to the other layer. As the colorant or the like added to the other layer, the colorant or the like that can be added to the material forming the above substrate can be listed.

[0048] The thickness of the substrate can be set to any appropriate value. The thickness of the substrate is preferably 10 μm to 200 μm, and more preferably 20 μm to 150 μm.

[0049] C. Adhesive Layer

[0050] The adhesive layer is formed of a active energy ray-curable adhesive containing a (meth)acrylic polymer having a radiation-polymerizable carbon-carbon double bond, an ionic liquid, and a photopolymerization initiator. If such an adhesive is used to form the adhesive layer, an adhesive tape that is excellent in antistatic properties and that can suppress surface contamination of the adherend caused by foreign matter can be provided. If a (meth)acrylic polymer having a radiation-polymerizable carbon-carbon double bond is used as the base polymer, the low-molecular-weight components from the adhesive can be suppressed. However, even if such a base polymer is used, there is room for improvement in the contamination of the surface of the adherend caused by foreign matter. In the adhesive of the embodiment of the present application, an ionic liquid is used together with a (meth)acrylic polymer having a radiation-polymerizable carbon-carbon double bond. The ionic liquid contained in the adhesive has a tendency to easily exude to the surface of the formed adhesive layer. If a (meth)acrylic polymer having a radiation-polymerizable carbon-carbon double bond and an ionic liquid are used in combination, the ionic liquid is enriched at the interface with the adherend, and the peeling of the adhesive tape from the adherend becomes easier. In addition, if the ionic liquid is enriched on the surface of the adhesive, the adhesion of foreign matter from the adhesive layer can also be suppressed.

[0051] C-1. (Meth)acrylic polymer having a radiation-polymerizable carbon-carbon double bond

[0052] As described above, a (meth)acrylic polymer having a radiation-polymerizable carbon-carbon double bond is used as the base polymer. Specifically, a (meth)acrylic polymer into which a radiation-polymerizable carbon-carbon double bond is introduced in the side chain and / or the terminal is used. More specifically, an acrylic polymer into which a radiation-polymerizable carbon-carbon double bond is introduced in the (meth)acrylic polymer is used. If an acrylic polymer is used, an adhesive tape that is easy to adjust the storage modulus and tensile modulus of the adhesive layer and that is excellent in the balance between the adhesion and the peelability can be obtained. Furthermore, the contamination of the surface of the adherend caused by the components from the adhesive can also be reduced. The (meth)acrylic polymer having a radiation-polymerizable carbon-carbon double bond can be used only one kind, or two or more kinds can be used in combination.

[0053] As the acrylic polymer, any appropriate acrylic polymer can be used. As the acrylic polymer, for example, a polymer obtained by polymerizing a monomer composition containing one or two or more kinds of esters of acrylic acid or methacrylic acid having a linear or branched alkyl group and a functional group-containing monomer can be cited. If a functional group-containing monomer is used, a polymer into which a radiation-polymerizable carbon-carbon double bond is easily introduced can be obtained.

[0054] The straight-chain or branched alkyl group is preferably an alkyl group having 30 or less carbon atoms, more preferably an alkyl group having 1 to 20 carbon atoms, and further preferably an alkyl group having 4 to 18 carbon atoms. As the alkyl group, specifically, there can be mentioned methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, t-butyl group, isobutyl group, pentyl group, isopentyl group, hexyl group, heptyl group, cyclohexyl group, 2-ethylhexyl group, octyl group, isooctyl group, nonyl group, isononyl group, decyl group, isodecyl group, undecyl group, lauryl group, tridecyl group, myristyl group, stearyl group, octadecyl group, dodecyl group, and the like.

[0055] The monomer composition can contain any other appropriate monomer. As the other monomer, for example, there can be mentioned carboxyl group-containing monomers such as acrylic acid, methacrylic acid, carboxyethyl acrylate, carboxypentyl acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid, and the like; anhydride monomers such as maleic anhydride, itaconic anhydride, and the like; hydroxyl group-containing monomers such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, 12-hydroxydodecyl (meth)acrylate, (4-hydroxymethylcyclohexyl)methyl acrylate, 2-hydroxyethyl vinyl ether, 4-hydroxybutyl vinyl ether, diethylene glycol monovinyl ether, and the like; sulfonic acid group-containing monomers such as styrene sulfonic acid, allyl sulfonic acid, 2-(meth)acrylamido-2-methylpropane sulfonic acid, (meth)acrylamidopropyl sulfonic acid, sulfopropyl (meth)acrylate, (meth)acryloyloxy naphthalene sulfonic acid, and the like; phosphoric acid group-containing monomers such as 2-hydroxyethyl acryloyl phosphate, and the like; and the like. As described above, if the functional group-containing monomer is contained, an acrylic polymer which easily introduces a radiation-polymerizable carbon-carbon double bond can be obtained. The content ratio of the functional group-containing monomer is preferably 4 to 30 parts by weight, and more preferably 6 to 20 parts by weight, relative to 100 parts by weight of the total monomer components.

[0056] The weight average molecular weight of the acrylic polymer is preferably 100,000 or more, more preferably 300,000 or more, further preferably 500,000 or more, and particularly preferably 6,000,000 to 30,000,000. If it is within such a range, an adhesive tape which suppresses bleeding of low molecular weight components and contamination of the adherend by foreign matter can be obtained. The molecular weight distribution (weight average molecular weight / number average molecular weight) of the acrylic polymer is preferably 1 to 20, and more preferably 3 to 10. If the acrylic polymer having a narrow molecular weight distribution is used, bleeding of low molecular weight components can be prevented, and an adhesive tape having low contamination can be obtained. Note that the weight average molecular weight and the number average molecular weight can be determined by gel permeation chromatography (solvent: tetrahydrofuran, polystyrene conversion).

[0057] The acrylic polymer having a radiation-polymerizable carbon-carbon double bond can be obtained by any appropriate method. For example, it can be obtained by reacting (e.g., condensation reaction, addition reaction) a polymer obtained by any appropriate polymerization method with a compound having a radiation-polymerizable carbon-carbon double bond. Specifically, in the case of using an acrylic polymer, an acrylic polymer (copolymer) having a structural unit derived from a monomer having any appropriate functional group is polymerized in any appropriate solvent, and then the functional group of the acrylic polymer is reacted with a compound having a radiation-polymerizable carbon-carbon double bond capable of reacting with the functional group, whereby an acrylic polymer into which a radiation-polymerizable carbon-carbon double bond is introduced can be obtained. The amount of the compound having a radiation-polymerizable carbon-carbon double bond that is reacted is preferably 4 parts by weight to 30 parts by weight, more preferably 4 parts by weight to 20 parts by weight, with respect to 100 parts by weight of the above-described acrylic polymer. As the solvent, any appropriate solvent can be used, and various organic solvents such as ethyl acetate, methyl ethyl ketone, toluene, and the like can be cited.

[0058] In the case of reacting the resin with the compound having a radiation-polymerizable carbon-carbon double bond as described above, the resin and the compound having a radiation-polymerizable carbon-carbon double bond preferably each have a functional group capable of reacting with the other. As the combination of the functional groups, carboxyl group / epoxy group, carboxyl group / aziridinyl group, hydroxyl group / isocyanate group, and the like can be cited. Among these combinations of the functional groups, the combination of hydroxyl group and isocyanate group is preferred from the viewpoint of ease of reaction tracing.

[0059] As the compound having a radiation-polymerizable carbon-carbon double bond, 2-isocyanatoethyl methacrylate, methacryloylisocyanate, 2-methacryloyloxyethyl isocyanate (2-isocyanatoethyl methacrylate), m-isopropenyl-α,α-dimethylbenzyl isocyanate, and the like can be cited.

[0060] D-2. Photopolymerization initiator

[0061] As the photopolymerization initiator, any appropriate initiator can be used. As the photopolymerization initiator, for example, acyloxyphosphine-based photoinitiators such as 2,4,6-trimethylbenzoylphenyl ethylphosphinate, (2,4,6-trimethylbenzoyl)phenylphosphine oxide, and the like; a-ketol-based compounds such as 4-(2-hydroxyethoxy)phenyl (2-hydroxy-2-propyl) ketone, a-hydroxy-a,a'-dimethylacetophenone, 2-methyl-2-hydroxypropiophenone, 1-hydroxycyclohexyl phenyl ketone, and the like; acetophenone-based compounds such as methoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxyacetophenone, 2-methyl-l-[4-(methylthio)-phenyl]-2-morpholinopropan-l-one, and the like; benzoin ether-based compounds such as benzoin ethyl ether, benzoin isopropyl ether, benzoin methyl ether, and the like; ketal-based compounds such as benzil dimethyl ketal; aromatic sulfonyl chloride-based compounds such as 2-naphthalenesulfonyl chloride; photoactive oxime-based compounds such as 1-phenyl-l,2-propanedione-2-(O-ethoxycarbonyl) oxime; benzophenone-based compounds such as benzophenone, benzoylbenzoic acid, 3,3'-dimethyl-4-methoxybenzophenone, and the like; thioxanthone-based compounds such as thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 2,4-dichlorothioxanthone, 2,4-diethylthioxanthone, 2,4-diisopropylthioxanthone, and the like; camphorquinone; halogenated ketones; acylphosphonate; a-hydroxyacetophenone such as 2-hydroxy-l-(4-(4-(2-hydroxy-2-methylpropanoyl)benzyl)phenyl-2-methylpropane-l-one. It is preferable that 2,2-dimethoxy-2-phenylacetophenone, 2-hydroxy-l-(4-(4-(2-hydroxy-2-methylpropanoyl)benzyl)phenyl-2-methylpropane-l-one be used. The photopolymerization initiator can be used alone or in combination with two or more.

[0062] In one embodiment, the photopolymerization initiator preferably has an extinction coefficient of 80 ml / g-cm or more, more preferably 90 ml / g-cm or more, and further preferably 100 ml / g-cm or more at a wavelength of 365 nm in methanol. The extinction coefficient at a wavelength of 365 nm is 800 ml / g-cm or less. If the extinction coefficient of the photopolymerization initiator is within the above range, the adhesive layer can be efficiently cured upon irradiation of active energy rays, and the adhesive layer can be subjected to easy release and cohesive failure can be suppressed. In addition, even if a substrate having excellent visual recognition (for example, a substrate having a transmittance of 60% or more for light at a wavelength of 365 nm) is used as the substrate, the adhesive layer can be efficiently cured, and cohesive failure can be suppressed. In the present specification, the extinction coefficient at a wavelength of 365 nm in methanol can be measured by any appropriate method.

[0063] As the photopolymerization initiator having an extinction coefficient of 80 ml / g-cm or more at a wavelength of 365 nm in methanol, commercially available products can be used. Specifically, the following can be mentioned: Omnirad 184 (88.6 ml / g-cm), Omnirad 127D (107 ml / g-cm), Omnirad 651 (361 ml / g-cm), and the like.

[0064] The photopolymerization initiator is used in any appropriate amount. The content of the photopolymerization initiator is preferably 0.50 parts by weight or less, more preferably 0.45 parts by weight or less, and further preferably 0.40 parts by weight or less, relative to 100 parts by weight of the (meth)acrylic polymer having a polymerizable carbon-carbon double bond. The content of the photopolymerization initiator is preferably 0.20 parts by weight or more. If the content of the photopolymerization initiator is within the above range, the content of the decomposition product that can be formed in the adhesive layer after irradiation with active energy rays can be reduced. As a result, the contamination of the adherend surface caused by foreign matter can be suppressed.

[0065] C-3. Ionic liquid

[0066] As the ionic liquid, any appropriate ionic liquid can be used, and specifically, a molten salt (room-temperature molten salt) composed of a pair of anion and cation, which is liquid at 25°C, can be used. If the active energy ray-curable adhesive contains an ionic liquid, the ionic liquid can be enriched in the surface of the adhesive layer on the adherend side in the formed adhesive layer. As a result, the contamination of the adherend surface caused by foreign matter from the adhesive tape can be suppressed. In addition, the ionic liquid can also function as an antistatic agent. Thus, the antistatic property can be imparted to the adhesive tape. The ionic liquid can be used alone or in combination of two or more.

[0067] As the anion of the ionic liquid, for example, the following can be mentioned: polyoxyethylene (2)-2-ethylhexyl ether sulfate anion, (FSO2)2N - , (CF3SO2)2N - , (CF3CF2SO2)2N - , (CF3SO2)3C - , Br - , AlCl4 - , Al2Cl7 - , NO3 - , BF4 - , PF6 - , CH3COO - , CF3COO - , CF3CF2CF2COO - , CF3SO3 - , CF3(CF2)3SO3- , AsF6 - , SbF6 - , and F (HF) n - and the like. Among them, as the anion, anions having a sulfonic acid group having 10 or more carbon atoms such as polyoxyethylene (2) -2-ethylhexyl ether sulfate anion and the like, and PF6 - , and (CF3SO2)2N - fluorine-containing anions such as the like. If these anions are used, there is a tendency that the ionic liquid is more easily precipitated on the surface of the adhesive layer, and the number of particles can be reduced.

[0068] As the cation of the ionic liquid, any appropriate cation can be used. Specifically, imidazolium cations, ammonium cations, pyrrolidinium cations, and pyridinium cations can be cited. Preferably, cations having an amino group such as ethylaminoethyl cation and the like can be cited. If these cations are used, the molecular weight of the cation is small, so it is easy to move in the adhesive layer, and the antistatic property can also be improved.

[0069] As the imidazolium cations, for example, 1-methylimidazolium cations, 1-ethyl-3-methylimidazolium cations, 1-propyl-3-methylimidazolium cations, 1-butyl-3-methylimidazolium cations, 1-pentyl-3-methylimidazolium cations, 1-hexyl-3-methylimidazolium cations, 1-heptyl-3-methylimidazolium cations, 1-octyl-3-methylimidazolium cations, 1-nonyl-3-methylimidazolium cations, 1-undecyl-3-methylimidazolium cations, 1-dodecyl-3-methylimidazolium cations, 1-tridecyl-3-methylimidazolium cations, 1-tetradecyl-3-methylimidazolium cations, 1-pentadecyl-3-methylimidazolium cations, 1-hexadecyl-3-methylimidazolium cations, 1-heptadecyl-3-methylimidazolium cations, 1-octadecyl-3-methylimidazolium cations, 1-undecyl-3-methylimidazolium Cation, 1 -benzyl-3-methylimidazole Cation, 1 -butyl-2,3-dimethylimidazole Cation and 1,3-bis(dodecyl)imidazole Cation, etc.

[0070] As pyridine Cationoid, for example, 1 -butylpyridine Cation, 1 -hexylpyridine Cation, 1 -butyl-3-methylpyridine Cation, 1 -butyl-4-methylpyridine Cation and 1 -octyl-4-methylpyridine Cation, etc.

[0071] As pyrrolidine Cationoid, for example, 1 -ethyl- 1 -methylpyrrolidine Cation and 1 -butyl- 1 -methylpyrrolidine Cation, etc.

[0072] As ammonium cationoid, for example, tetraethylammonium cation, tetrabutylammonium cation, methyltrioctylammonium cation, tetradecyltrihexylammonium cation, glycidyltrimethylammonium cation, and trimethylaminoethyl acrylate cation, etc.

[0073] As ionic liquid, it is preferable to use a compound containing a cation having an amino group, and an anion having a sulfonic acid group having a carbon number of 10 or more or PF6 - and (CF3S02)2N - containing fluorine anion. Specifically, it is possible to use an ionic liquid containing 1 -butyl-3-methylpyridinium cation and (CF3S02)2N - , an ionic liquid containing 1 -butyl-3-methylimidazolium cation and PF6 - , an ionic liquid containing ethylethanolammonium cation and polyoxyethylene (2) -2-ethylhexyl ether sulfate anion, etc. If these ionic liquids are used, it is possible to provide an adhesive tape capable of further inhibiting contamination of the adherend surface caused by attachment of foreign matter, and further exerting antistatic properties.

[0074] As ionic liquid, it is possible to use a commercially available product. Specifically, it is possible to cite: CIL-312, CIL-625, CIL-635, CIL-R50, etc. manufactured by Carlit Corporation, Japan; and AS-100, etc. manufactured by Emulsifier Corporation, Japan.

[0075] The content of the ionic liquid is preferably 1.0 part by weight to 3.0 parts by weight, more preferably 1.3 parts by weight to 2.6 parts by weight, and further preferably 1.6 parts by weight to 2.2 parts by weight, relative to 100 parts by weight of the (meth)acrylic polymer having a radiation-polymerizable carbon-carbon double bond. If the content of the ionic liquid is within the above range, an adhesive tape that can further suppress contamination of the adherend surface caused by attachment of foreign matter and further exert antistatic properties can be provided.

[0076] C-4. Polyalkylene glycol

[0077] The active energy ray-curable adhesive preferably further contains a polyalkylene glycol. If the active energy ray-curable adhesive further contains a polyalkylene glycol, the components contained in the adhesive layer, such as the ionic liquid, can move in the adhesive layer even after irradiation of the active energy ray. As a result, the decrease in the antistatic properties in the adhesive layer after active energy ray irradiation can be suppressed. The polyalkylene glycol can be used alone or in combination with two or more kinds.

[0078] As the polyalkylene glycol, for example, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, ethylene glycol-propylene glycol copolymer, and the like can be given. It is preferable to use polyethylene glycol and polypropylene glycol. If these polyalkylene glycols are used, these polyalkylene glycols, like the ionic liquid, can be enriched on the surface of the adherend side of the adhesive layer. As a result, contamination of the adherend surface caused by foreign matter from the adhesive tape can be suppressed. In addition, even with a small amount of addition, since the mobility of the ionic liquid is improved, effects can be obtained particularly in terms of antistatic properties of the adhesive surface after ultraviolet curing. In addition, a derivative of the polyalkylene glycol can also be used instead of the polyalkylene glycol. In the case of using a derivative of the polyalkylene glycol, a derivative of the polyalkylene glycol that is liquid at 0°C can be used.

[0079] The number average molecular weight of the polyalkylene glycol can be set to any appropriate value. If it is polyethylene glycol, the number average molecular weight of the polyalkylene glycol is preferably 200 to 600. If it is polypropylene glycol, the number average molecular weight is preferably 200 to 4200, more preferably 400 to 3000, and further preferably 600 to 2000. If the number average molecular weight of the polyalkylene glycol is within the above range, the polyalkylene glycol can be enriched on the surface of the adherend side of the adhesive layer. As a result, contamination of the adherend surface caused by foreign matter from the adhesive tape can be suppressed.

[0080] The content of the polyalkylene glycol is preferably 0.05 parts by weight to 0.35 parts by weight, more preferably 0.15 parts by weight to 0.25 parts by weight, relative to 100 parts by weight of the (meth)acrylic polymer having a radiation-polymerizable carbon-carbon double bond. If the content of the polyalkylene glycol is within the above range, an adhesive tape that can suppress generation of foreign matter and that can exert an excellent antistatic function even after irradiation with active energy rays can be obtained.

[0081] C-4. Additives

[0082] The adhesive can contain any appropriate additive as needed. As the additive, for example, a crosslinking agent, a catalyst (e.g., a platinum catalyst), a tackifier, a plasticizer, a pigment, a dye, a filler, an anti-aging agent, an electrically conductive material, an ultraviolet absorber, a light stabilizer, a release adjusting agent, a softening agent, a surfactant, a flame retardant, a solvent, or the like can be exemplified.

[0083] In one embodiment, the adhesive further contains a crosslinking agent. As the crosslinking agent, for example, an isocyanate-based crosslinking agent, an epoxy-based crosslinking agent, an aziridine-based crosslinking agent, a chelate-based crosslinking agent, or the like can be exemplified. The content of the crosslinking agent is preferably 0.2 parts by weight to 10 parts by weight, more preferably 0.3 parts by weight to 5 parts by weight, and further preferably 0.5 parts by weight to 4 parts by weight, relative to 100 parts by weight of the base polymer contained in the adhesive. If the content of the crosslinking agent is within the above range, the adhesion of foreign matter from the adhesive to the surface of the adherend can be suppressed.

[0084] In one embodiment, an isocyanate-based crosslinking agent is preferably used. The isocyanate-based crosslinking agent is preferable in terms of being able to react with a variety of functional groups. If an isocyanate-based crosslinking agent is used as the crosslinking agent and the content of the crosslinking agent is within the above range, the contamination of the surface of the adherend by foreign matter from the adhesive layer can be further suppressed.

[0085] The thickness of the adhesive layer can be set to any appropriate value. The thickness of the adhesive layer is preferably 3 μm to 500 μm, more preferably 4 μm to 400 μm, and further preferably 5 μm to 350 μm. If the thickness of the adhesive layer is within the above range, sufficient adhesion to the adherend can be exerted. Note that, in the case where the adhesive tape contains an intermediate layer as the other layer, the thickness of the adhesive layer described above refers to the total thickness of the adhesive layer and the intermediate layer.

[0086] The surface resistivity of the adhesive layer before irradiation with active energy rays is preferably 5 x 10 11 Ω / □ or less. The surface resistivity before irradiation with active energy rays is, for example, 1 x 10 10 Ω / □ or less. If the surface resistivity of the adhesive layer before irradiation with active energy rays is within the above range, an adhesive tape having excellent antistatic properties can be obtained.

[0087] The surface resistivity of the adhesive layer after irradiation with active energy rays is preferably 1 x 10 12 Ω / D. If the surface resistivity of the adhesive layer after irradiation with active energy rays is within the above range, the peeling static electricity at the time of peeling the adhesive tape from the adherend can be suppressed, and for example, the static electricity destruction of a circuit can be suppressed in the case where the adherend is a wafer.

[0088] The gel fraction of the adhesive layer after irradiation with active energy rays is preferably 97.5% or more, and more preferably 98% or more. If the gel fraction of the adhesive layer after irradiation with active energy rays is within the above range, the adhesion of foreign matter from the adhesive layer to the surface of the adherend can be suppressed. The gel fraction of the adhesive layer after irradiation with active energy rays can vary depending on the components contained in the adhesive, and for example, is 99.0% or less. In the present specification, the gel fraction of the adhesive layer after irradiation with active energy rays refers to a value measured by the following method.

[0089] < Gel fraction after irradiation with active energy rays >

[0090] Using a UV irradiation device (manufactured by Sibata Scientific Technology Ltd., product name "UM-810"), active energy rays were irradiated from the adhesive layer side of the adhesive tape with a cumulative light quantity of 460 mJ / cm 2 from the adhesive layer side of the adhesive tape with a cumulative light quantity of 460 mJ / cm

[0091] Gel fraction (%) = weight (g) of the sample after toluene immersion / weight (g) of the sample before toluene immersion

[0092] The amount of Si on the surface of the adhesive layer after peeling the release liner is preferably 3.5 atomic % or less, more preferably 1.0 atomic % or less, and further preferably 0.5 atomic % or less, as measured by X-ray photoelectron spectroscopy. As described above, the adhesive tape is stored with the release liner stacked on the surface of the adhesive layer for the purpose of protecting the adhesive layer during the period until use. During the storage period, sometimes a component such as a release agent is transferred from the surface of the release liner to the surface of the adhesive layer. Such a transfer of additives or the like from the surface of the release liner to the surface of the adhesive layer can also be a cause of contamination of the surface of the adherend. If the amount of Si on the surface of the adhesive layer after peeling the release liner is within the above range, contamination caused by attachment of foreign matter to the surface of the adherend can be reduced.

[0093] The adhesive layer can have any appropriate adhesive strength. The adhesive strength of the adhesive layer before ultraviolet irradiation against a silicon wafer is preferably 0.50 N / 20 mm to 40 N / 20 mm, more preferably 1.00 N / 20 mm to 35 N / 20 mm, and further preferably 1.5 N / 20 mm to 30 N / 20 mm. In the present specification, the adhesive strength of the adhesive layer refers to a value measured by cutting the adhesive tape to a width of 20 mm and a length of 80 mm, pressing the adhesive layer of the adhesive tape against the mirror surface of a silicon mirror wafer with a 2-kg roller for one round trip in an atmosphere at 23°C, leaving it for 30 minutes at 23°C, and then measuring the value by a 180° peeling test at a pulling speed of 300 mm / minute in an atmosphere at 23°C and 50% RH.

[0094] The adhesive strength of the adhesive layer after ultraviolet irradiation against a silicon wafer is preferably 0.001 N / 20 mm to 1.000 N / 20 mm, more preferably 0.005 N / 20 mm to 0.850 N / 20 mm, and further preferably 0.005 N / 20 mm to 0.800 N / 20 mm. The adhesive strength after ultraviolet irradiation refers to a value measured by cutting the adhesive tape to a width of 20 mm and a length of 80 mm, pressing the adhesive layer of the adhesive tape against the mirror surface of a silicon mirror wafer with a 2-kg roller for one round trip in an atmosphere at 23°C, leaving it for 30 minutes at 23°C, and then measuring the value by a 180° peeling test at a pulling speed of 300 mm / minute in an atmosphere at 23°C and 50% RH, with irradiation of ultraviolet light (UV) from the substrate side of the adhesive tape in a manner such that the cumulative light quantity is 460 mJ / cm 2 (wavelength 365 nm) (in the case where the extinction coefficient of the photopolymerization initiator at a wavelength of 365 nm in methanol is less than 80 ml / g-cm, the cumulative light quantity is 700 mJ / cm 2 ).

[0095] D. Release liner

[0096] As described above, the adhesive tape can be stored in a state where a release liner is attached to the adhesive layer for the purpose of protecting the adhesive layer until the time of actual use. The release liner typically has a base film and a light release layer. As the release agent constituting the light release layer, any appropriate release agent can be used. For example, a release agent such as a silicon-containing release agent, a fluorine-containing release agent, a long-chain alkyl acrylate release agent, or the like can be used.

[0097] As the base film, any appropriate base film can be used, and for example, a plastic (e.g., polyethylene terephthalate (PET), polyethylene, polypropylene) film, a nonwoven fabric, or paper, or the like can be used.

[0098] The light release layer can be formed by applying a composition containing the above-described release agent to the base film. The thickness of the light release layer is preferably 0.06 μm or less, and more preferably 0.03 μm to 0.06 μm. If the thickness of the light release layer is within the above-described range, the transfer of the release agent or the like from the release liner to the surface of the adhesive layer can be suppressed, and as a result, the contamination of the surface of the adherend by foreign matter from the adhesive tape can be suppressed.

[0099] E. Method for manufacturing adhesive tape

[0100] The adhesive tape can be manufactured by any appropriate method. In one embodiment, the adhesive tape can be produced, for example, by forming an adhesive layer on a base material. The adhesive layer can be formed by applying the adhesive for forming the above-described adhesive layer to a base material to form each layer, or each layer can be formed on any appropriate release liner and then transferred. As the application method, various methods such as bar coater application, air knife application, gravure application, gravure reverse application, reverse roll application, lip die application, slot die application, dip coating, offset printing, flexographic printing, screen printing, or the like can be used. Alternatively, a method in which an adhesive layer is formed on a release liner and then attached to a base material can be used.

[0101] F. Use of adhesive tape

[0102] The adhesive tape of the embodiment of the present application can be suitably used for the protection of the circuit surface of a semiconductor wafer in a semiconductor processing step. As described above, the adhesive tape of the embodiment of the present application has excellent antistatic properties, and the surface contamination of the adherend caused by foreign matter can be suppressed. Therefore, the adhesion of foreign matter to the circuit surface can be suppressed, and the electrostatic destruction of the circuit caused by release static electricity can also be suppressed.

[0103] In one embodiment, the adhesive tape of the embodiment of the present application can be suitably used for surface protection of optical articles and optical glass articles. In optical articles and optical glass articles, attachment of foreign matter to the surface and damage to the surface can affect the characteristics such as refractive index, and it can be impossible to exert the prescribed performance. In addition, it can be difficult to perform a cleaning process after shipment. If the adhesive tape of the embodiment of the present application is used as a surface protection tape for optical articles and optical glass articles, not only can the surface of the optical articles and optical glass articles be protected from damage and contamination during the period until use, but also surface contamination of the optical articles and optical glass articles caused by foreign matter from the surface protection tape after peeling of the surface protection tape can be suppressed.

[0104] Example

[0105] Hereinafter, the present application will be specifically described by way of examples, but the present application is not limited to these examples. In the examples, unless otherwise specified, "parts" and "%" are on a weight basis.

[0106] [Production Example 1] Production of Base Polymer

[0107] A polymerization apparatus was used which was equipped with a detachable lid, a separatory funnel, a thermometer, a nitrogen gas introduction tube, a Liebig condenser, a vacuum seal, a stirring rod, and a stirring blade in a 1 L round bottom detachable flask. Into this polymerization apparatus, 100 parts by weight of butyl acrylate (BA), 80 parts by weight of ethyl acrylate (EA), 40 parts by weight of 2-hydroxyethyl acrylate (HEA), 0.2 parts by weight of benzoyl peroxide, and 500 parts by weight of toluene were charged. Subsequently, a polymerization treatment was performed at 61°C for 6 hours under a nitrogen gas stream. Subsequently, 41 parts by weight of a compound having a radiation-polymerizable carbon-carbon double bond (manufactured by Showa Denko K.K., trade name "Karenz MOI") was added to the polymerization apparatus, and a reaction was performed at 50°C for 24 hours, thereby obtaining a polymer A (base polymer) having a weight average molecular weight of 700,000 with a double bond introduced in the side chain.

[0108] [Production Example 2] Production of Release Liner

[0109] A light release layer forming composition (a liquid prepared from 100 parts by weight of "KS-776L" (manufactured by Shin-Etsu Silicone Co., Ltd.), 2 parts by weight of "CAT-PLR-1" (manufactured by Shin-Etsu Silicone Co., Ltd.), 1 part by weight of "CAT-PLR-2" (manufactured by Shin-Etsu Silicone Co., Ltd.), 2215 parts by weight of n-hexane, 2215 parts by weight of n-heptane, and 5 parts by weight of "CAT-PL-50T" (manufactured by Shin-Etsu Silicone Co., Ltd.)) was applied to a polyethylene terephthalate (PET) base film (manufactured by Toyobo Co., Ltd., trade name "Lumirror S-105", thickness 38 μm) at a dry thickness of 0.05 μm using a bar coater, and dried at 130°C, thereby obtaining a release liner.

[0110] [Production Example 3] Production of Base Material

[0111] A urethane-based easy-adhesion-treated layer having a thickness of 1.5 μm was formed on a polyethylene terephthalate (PET) film (manufactured by Toyobo Co., Ltd., trade name "Lumirror S-105", thickness 50 μm) by gravure printing, thereby obtaining a release liner B. Copper phthalocyanine was contained in the urethane-based easy-adhesion-treated layer at a concentration such that the transmittance of light having a wavelength of 365 nm was 70%.

[0112] [Example 1]

[0113] A base polymer obtained in Production Example 1 (100 parts by weight), a crosslinking agent (manufactured by Mitsui Chemicals, Inc., trade name "TAKENATE D-101A") (3 parts by weight), a photopolymerization initiator 1 (manufactured by IGM Resins, trade name "omnirad 127D", extinction coefficient in methanol at 365 nm: 107 ml / g-cm) (0.3 parts by weight), an ionic liquid 1 (manufactured by Japan Carlit Co., Ltd., trade name "CIL312", cation: 1-butyl-3-methylpyridinium Cation, anion: (CF3SO2)2N - ) (2 parts by weight), a polyalkylene glycol 1 (polypropylene glycol (PPG), manufactured by Nippon Oil & Fats Co., Ltd., trade name "UNIOL D-1200") (0.2 parts by weight) were mixed, and ethyl acetate was appropriately added, thereby obtaining an adhesive solution.

[0114] The obtained adhesive solution was applied to the release liner produced in Production Example 2, and dried at 120°C for 2 minutes, thereby forming an adhesive layer having a thickness of 10 μm. Subsequently, the base material produced in Production Example 3 was attached to the surface of the adhesive layer on which the release liner was not laminated, and subjected to aging treatment at 50°C for 48 hours, thereby obtaining an adhesive tape.

[0115] [Example 2]

[0116] The adhesive tape was obtained by replacing the release liner made in Manufacturing Example 2 with a commercially available release liner (manufactured by Mitsubishi Resin Co., Ltd., trade name "MRF38", thickness 38μm), except that the operation was the same as in Example 1.

[0117] [Example 3]

[0118] Except for the absence of polyalkylene glycol 1, the procedure was the same as in Example 1 to obtain an adhesive solution. Except for the use of the obtained adhesive solution, the procedure was the same as in Example 1 to obtain an adhesive tape.

[0119] [Example 4]

[0120] The adhesive tape was obtained by replacing polyalkylene glycol 1 with 0.2 parts by weight of polyethylene glycol (PEG) (manufactured by Sanyo Chemical Industry Co., Ltd., trade name "PEG-200"), otherwise operated in the same manner as in Example 1.

[0121] [Example 5]

[0122] 1.6 parts by weight of ionic liquid 2 (manufactured by Carlit Corporation, Japan, trade name CIL625), cation: 1-butyl-3-methylimidazolium Cations and anions: PF6 - Instead of ionic liquid 1, the same procedure as in Example 1 was followed to obtain the adhesive tape.

[0123] [Example 6]

[0124] The adhesive tape was obtained by replacing ionic liquid 1 with 2.0 parts by weight of ionic liquid 3 (manufactured by Nippon Emulsifier Co., Ltd., trade name "AMINOIONAS100", anion: ethyl ethanol ammonium cation, anion: polyoxyethylene (2)-2-ethylhexyl ether sulfate anion), otherwise operated in the same manner as in Example 1.

[0125] [Example 7]

[0126] The adhesive tape was obtained by replacing polyalkylene glycol 1 with 0.2 parts by weight of polyethylene glycol (PEG) (manufactured by Sanyo Chemical Industry Co., Ltd., trade name "PEG-200"), otherwise operated in the same manner as in Example 6.

[0127] [Example 8]

[0128] The same operation as in Example 1 was performed except that no polyalkylene glycol 1 was added, whereby an adhesive solution was obtained. The same operation as in Example 6 was performed except that the obtained adhesive solution was used, whereby an adhesive tape was obtained.

[0129] [Example 9]

[0130] The same operation as in Example 1 was performed except that 0.3 parts by weight of photopolymerization initiator 2 (manufactured by IGM Resins Co., trade name "omnirad 2959", extinction coefficient in methanol under 365 nm is 48.9 ml / g-cm) was used instead of photopolymerization initiator 1, whereby an adhesive tape was obtained.

[0131] [Example 10]

[0132] The same operation as in Example 6 was performed except that 0.3 parts by weight of photopolymerization initiator 2 (manufactured by IGM Resins Co., trade name "omnirad 2959", extinction coefficient in methanol under 365 nm is 48.9 ml / g-cm) was used instead of photopolymerization initiator 1, whereby an adhesive tape was obtained.

[0133] [Example 11]

[0134] The same operation as in Production Example 3 was performed except that the urethane-based easy-adhesive treatment layer was made to contain copper phthalocyanine at a concentration such that the transmittance of light at a wavelength of 365 nm was 60%, whereby a substrate having a light transmittance of 60% was produced. The same operation as in Example 6 was performed except that the obtained substrate was used, whereby an adhesive tape was obtained.

[0135] [Table 1]

[0136]

[0137] (Comparative Example 1)

[0138] 80 parts by weight of butyl acrylate (BA), 15 parts by weight of acrylonitrile, and 5 parts by weight of acrylic acid were copolymerized in ethyl acetate by a conventional method, whereby a solution containing an acrylic copolymer having a number average molecular weight of 800,000 was obtained. To the solution, 10 parts by weight of a diol-type polypropylene glycol having a molecular weight of 3,000 and 3 parts by weight of a polyisocyanate compound (manufactured by Mitsui Chemicals, Inc., trade name "TAKENATE D-101A") were added, whereby an acrylic adhesive solution was obtained.

[0139] The obtained acrylic adhesive solution was coated on a 50-μm polyethylene terephthalate (PET) substrate (manufactured by Toyobo Co., Ltd., product name "Lumirror S-105") subjected to corona treatment, and heated at 80°C for 3 minutes, thereby obtaining an adhesive tape.

[0140] (Comparative Example 2)

[0141] A solution containing an acrylic polymer having a weight average molecular weight of 650,000 was obtained by copolymerizing 75 parts by weight of methyl acrylate, 10 parts by weight of methoxyethyl acrylate, 5 parts by weight of N-vinylpyrrolidone, and 10 parts by weight of 2-hydroxyethyl acrylate in ethyl acetate by a conventional method. Next, 12 parts by weight of a compound having a radiation-polymerizable carbon-carbon double bond (manufactured by Showa Denko K.K., trade name "Karenz MOI") was added to the solution containing the acrylic polymer, and a solution of a double-bond-introduced acrylic polymer having a weight average molecular weight of 650,000 was obtained by a conventional method. Next, 70 parts by weight of an ultraviolet-curable oligomer obtained by reacting pentaerythritol triacrylate and diisocyanate, 3 parts by weight of a photopolymerization initiator (manufactured by IGM Resins Co., trade name "omnirad 651", extinction coefficient in methanol at 365 nm: 361 ml / g-cm), 2 parts by weight of a polyisocyanate compound (manufactured by Mitsui Chemicals, Inc., trade name "TAKENATE D-101A"), and 10 parts by weight of a polypropylene glycol having a number average molecular weight of 2,000 were added to the solution of the double-bond-introduced acrylic polymer, thereby obtaining an acrylic adhesive solution.

[0142] The obtained acrylic adhesive solution was coated on a 50-μm polyethylene terephthalate (PET) substrate (manufactured by Toyobo Co., Ltd., product name "Lumirror S-105") subjected to corona treatment, and heated at 80°C for 3 minutes, thereby obtaining an adhesive tape.

[0143] (Comparative Example 3)

[0144] A solution of an acrylic polymer having a weight average molecular weight of 1.1 million was obtained by charging 30 parts by weight of 2-ethylhexyl acrylate, 70 parts by weight of methyl acrylate, 10 parts by weight of acrylic acid, and 0.2 parts by weight of benzoyl peroxide, and polymerizing at 60°C for 6 hours under a nitrogen atmosphere. 100 parts by weight of the obtained acrylic polymer, 50 parts by weight of UV oligomer 1 (manufactured by Mitsubishi Chemical Corporation, trade name "Irgacure UV-1700TL"), 45 parts by weight of UV oligomer 2 (manufactured by Mitsubishi Chemical Corporation, trade name: Irgacure UV-3000TL), 15 parts by weight of an adhesion promoter (manufactured by An-Chemical Corporation, trade name "M-G125"), 0.2 parts by weight of a light release agent (manufactured by Toho Chemical Industry Co., Ltd., trade name "Phosphanol RL-210"), 4.5 parts by weight of an ionic liquid (manufactured by the First Industrial Co., Ltd., trade name "ELEXCEL AS-110", cation: 1-ethyl-3-methylimidazolium, anion: bis(fluorosulfonyl)imide), 3 parts by weight of a photopolymerization initiator (manufactured by IGM Resins B.V, trade name "Omnirad 2959", extinction coefficient in methanol at 365 nm: 48.9 ml / g-cm), 5 parts by weight of a polyisocyanate compound (manufactured by Mitsui Chemicals, Inc., trade name "TAKENATE D-101A"), and toluene were mixed, thereby obtaining an adhesive solution. Cation, anion: bis(fluorosulfonyl)imide), 3 parts by weight of a photopolymerization initiator (manufactured by IGM Resins B.V, trade name "Omnirad 2959", extinction coefficient in methanol at 365 nm: 48.9 ml / g-cm), 5 parts by weight of a polyisocyanate compound (manufactured by Mitsui Chemicals, Inc., trade name "TAKENATE D-101A"), and toluene were mixed, thereby obtaining an adhesive solution.

[0145] The obtained adhesive solution was applied to a 50-μm polyethylene terephthalate (PET) substrate (manufactured by Toray Industries, Inc., product name "Lumirror S-105") that had been subjected to corona treatment, and heated at 80°C for 3 minutes, thereby obtaining an adhesive tape.

[0146] (Comparative Example 4)

[0147] A solution of an acrylic polymer having a weight average molecular weight of 1.1 million was obtained by charging 30 parts by weight of 2-ethylhexyl acrylate, 70 parts by weight of methyl acrylate, 10 parts by weight of acrylic acid, and 0.2 parts by weight of benzoyl peroxide, and polymerizing at 60°C for 6 hours under a nitrogen atmosphere. 100 parts by weight of the obtained acrylic polymer, 50 parts by weight of UV oligomer 1 (manufactured by Mitsubishi Chemical Corporation, trade name "Irgacure UV-1700TL"), 45 parts by weight of UV oligomer 2 (manufactured by Mitsubishi Chemical Corporation, trade name: Irgacure UV-3000TL), 15 parts by weight of an adhesion promoter (manufactured by An-Chemical Corporation, trade name "M-G125"), 0.2 parts by weight of a light release agent (manufactured by Toho Chemical Industry Co., Ltd., trade name "Phosphanol RL-210"), 4.5 parts by weight of an ionic liquid (manufactured by the First Industrial Co., Ltd., trade name "ELEXCEL AS-110", cation: 1-ethyl-3-methylimidazolium, anion: bis(fluorosulfonyl)imide), 3 parts by weight of a photopolymerization initiator (manufactured by IGM Resins B.V, trade name "Omnirad 2959", extinction coefficient in methanol at 365 nm: 48.9 ml / g-cm), 5 parts by weight of a polyisocyanate compound (manufactured by Mitsui Chemicals, Inc., trade name "TAKENATE D-101A"), and toluene were mixed, thereby obtaining an adhesive solution. Cation, anion: bis(fluorosulfonyl)imide), 3 parts by weight of a photopolymerization initiator (manufactured by IGM Resins B.V, trade name "Omnirad 2959", extinction coefficient in methanol at 365 nm: 48.9 ml / g-cm), 5 parts by weight of a polyisocyanate compound (manufactured by Mitsui Chemicals, Inc., trade name "TAKENATE D-101A"), and toluene were mixed, thereby obtaining an adhesive solution. -), 3 parts by weight of a photopolymerization initiator (manufactured by IGM Resins B.V., trade name "omnirad 2959", extinction coefficient in methanol under 365 nm: 48.9 ml / g-cm), and 5 parts by weight of a polyisocyanate compound (manufactured by Mitsui Chemicals, Inc., trade name "TAKENATE D-101A"), whereby an adhesive solution was obtained.

[0148] The obtained adhesive solution was applied to a 50-μm polyethylene terephthalate (PET) substrate (manufactured by Toyobo Co., Ltd., product name "Lumirror S-105") subjected to corona treatment, and heated at 80°C for 3 minutes, whereby an adhesive tape was obtained.

[0149] (Comparative Example 5)

[0150] A polymer solution containing a polymer having a weight average molecular weight of 1.2 million was obtained by copolymerizing 75 parts by weight of 2-ethylhexyl acrylate, 25 parts by weight of N-acryloylmorpholine, 3 parts by weight of acrylic acid, 0.1 part by weight of hydroxyethyl acrylate, and 0.2 part by weight of 2,2'-azobisisobutyronitrile in ethyl acetate. To the obtained polymer solution, 2 parts by weight of a light peeling agent (manufactured by the First Industrial Co., Ltd., trade name "EPAN 710"), 7 parts by weight of an ionic liquid (manufactured by Nikko Emulsion Co., Ltd., trade name "AMINOION AS100", cation: ethyl ethanolammonium cation, anion: polyoxyethylene (2)-2-ethylhexyl ether sulfate anion), and 4 parts by weight of a polyisocyanate compound (manufactured by Mitsui Chemicals, Inc., trade name "TAKENATE D-101A") were added, whereby an adhesive solution was obtained.

[0151] The obtained adhesive solution was applied to a 50-μm polyethylene terephthalate (PET) substrate (manufactured by Toyobo Co., Ltd., product name "Lumirror S-105") subjected to corona treatment, and heated at 80°C for 3 minutes, whereby an adhesive tape was obtained.

[0152] <Evaluation>

[0153] The following evaluations were performed using the adhesive tapes obtained in the examples and comparative examples. The results are shown in Table 2.

[0154] <Silicone transfer amount (amount of Si)>

[0155] The release liner was peeled from the adhesive layer of the adhesive tape. Next, the adhesive surface of the adhesive layer after the release liner was peeled was measured for the ratio of Si (atomic %) on the surface of the adhesive layer using X-ray photoelectron spectroscopy with an ESCA (electron spectroscopy for chemical analysis) device. In the measurement, an ESCA device "KRATOS ULTRA2" manufactured by Shimadzu Corporation was used, and qualitative analysis was performed by wide scan measurement under the following conditions: X-ray source: monochromatic Al Kα (5 mA, 75 W, resolution 40), photoelectron take-off angle: 90°, analysis area: 1.1 mmφ, and narrow scan measurement was performed on the detected elements.

[0156] <Particle count>

[0157] The adhesive tape was cut into 25 cm x 25 cm to make a sample. The sample was attached to a 6-inch mirror wafer. Then, it was left to stand for 2 hours at 23°C. Next, active energy rays (ultraviolet rays) were irradiated using a dicing process UV irradiation device (manufactured by J.E.D. Precision Machine Co., Ltd., product name UM-810). In the case where the extinction coefficient of the photopolymerization initiator contained in the adhesive layer at a wavelength of 365 nm in methanol was 80 ml / g-cm or more, active energy rays were irradiated in a manner such that the cumulative light quantity was 460 mJ / cm 2 , and in the case where the extinction coefficient of the photopolymerization initiator at a wavelength of 365 nm in methanol was less than 80 ml / g-cm, active energy rays were irradiated in a manner such that the cumulative light quantity was 700 mJ / cm 2 . Then, the adhesive tape was peeled from the wafer surface, and wafer surface particle measurement was performed using a wafer surface inspection device (manufactured by TAKANO Corporation, product name "WM-7S"), and the particle count of particles equal to or greater than 0.15 μm and less than 0.30 μm and the particle count of particles of 0.30 μm or more were measured.

[0158] <Gel fraction>

[0159] The release liner was peeled from the adhesive tape, and active energy rays were irradiated from the adhesive layer side of the adhesive tape using a UV irradiation device (manufactured by J.E.D. Precision Machine Co., Ltd., product name "UM-810") in a manner such that the cumulative light quantity was 460 mJ / cm 2 . Next, about 0.1 g of a sample was collected from the adhesive layer of the adhesive tape after ultraviolet irradiation, and the weight was measured. The collected sample was wrapped with a Teflon porous membrane, and left to stand in toluene for 1 week. Then, the sample was taken out of the Teflon porous membrane, and toluene was dried by heating the sample in an oven at 120°C for 1 hour, and the weight was measured. Based on the measured weight, the gel fraction was calculated based on the following formula.

[0160] Gel fraction (%) = weight (g) of the sample after toluene immersion / weight (g) of the sample before toluene immersion

[0161] <surface resistivity>

[0162] The surface resistivity of the adhesive layer surface of the adhesive tape was measured using a resistivity meter (manufactured by Mitsubishi Chemical Corporation, product name "Hiresta MCP-HT450") under the conditions of 23°C, 55% RH, an applied voltage of 100 V, and 30 seconds. In addition, the release liner was peeled from the adhesive tape, and a UV irradiation device (manufactured by JEO Co., Ltd., product name "UM-810") was used to irradiate active energy rays from the adhesive layer side of the adhesive tape in a manner such that the cumulative light quantity was 460 mJ / cm 2 The surface resistivity of the adhesive layer surface of the adhesive tape was measured using a resistivity meter (manufactured by Mitsubishi Chemical Corporation, product name "Hiresta MCP-HT450") under the conditions of 23°C, 55% RH, an applied voltage of 100 V, and 30 seconds. In addition, the release liner was peeled from the adhesive tape, and a UV irradiation device (manufactured by JEO Co., Ltd., product name "UM-810") was used to irradiate active energy rays from the adhesive layer side of the adhesive tape in a manner such that the cumulative light quantity was 460 mJ / cm

[0163] <light transmittance>

[0164] The transmittance of the film used as the substrate was measured using a spectrophotometer (manufactured by Shimadzu Corporation, product name "UV-2550") in the range of wavelengths of 200 nm to 800 nm, and the transmittance of light at a wavelength of 365 nm was calculated.

[0165] <thickness of the light release layer>

[0166] The release liner used in the examples and comparative examples was embedded in an epoxy resin. The embedded release liner was cut, and the length of any 10 points on the cut surface was measured using a transmission electron microscope, and the average value was calculated. Note that for portions in which the thickness of the light release layer was extremely thin, the points were not used for the measurement of the thickness.

[0167] [Table 2]

[0168]

[0169]

[0170] The adhesive tape of the examples of the present application has an appropriate surface resistivity even after irradiation of active energy rays. In addition, the transfer of Si to the surface of the adhesive layer is also suppressed, and the attachment of foreign matter to the surface of the adherend is also suppressed.

[0171] industrial applicability

[0172] The adhesive tape of the embodiments of the present application is suitable for use in the protection of the circuit surface of a semiconductor wafer, and the protection of the surface of optical products and optical glass products.

Claims

1. An adhesive tape, wherein, The adhesive tape has a substrate and an adhesive layer formed of a active energy ray-curable adhesive containing a (meth)acrylic polymer having a radiation-polymerizable carbon-carbon double bond, an ionic liquid, and a photopolymerization initiator.

2. The adhesive tape according to claim 1, wherein The gel fraction of the active energy ray-curable adhesive after active energy ray irradiation is 97.5% or more.

3. The adhesive tape according to claim 1, wherein The cation of the ionic liquid has an amino group.

4. The adhesive tape according to claim 1, wherein The anion of the ionic liquid has a sulfonic acid group.

5. The adhesive tape according to claim 1, wherein The surface resistivity of the adhesive layer before irradiation with active energy rays is 5 x 10 11 Ω / □ or less.

6. The adhesive tape according to claim 1, wherein The active energy ray-curable adhesive further contains a polyalkylene glycol.

7. The adhesive tape according to claim 6, wherein The polyalkylene glycol is at least one selected from the group consisting of polyethylene glycol and polypropylene glycol.

8. The adhesive tape according to claim 1, wherein The substrate has a light transmittance of 60% or more at a wavelength of 365 nm.

9. The adhesive tape according to claim 8, wherein The photopolymerization initiator has an extinction coefficient of 80 ml / g·cm or more at a wavelength of 365 nm in methanol.

10. The adhesive tape according to claim 1, wherein The content of the photopolymerization initiator is 0.5 parts by weight or less with respect to 100 parts by weight of the (meth)acrylic polymer.

11. The adhesive tape according to claim 1, wherein The substrate is a polyethylene terephthalate film.

12. The adhesive tape according to claim 1, wherein A release liner having a light peeling layer with a thickness of 0.06 μm or less is further laminated on the adhesive layer.

13. The adhesive tape according to claim 12, wherein, The amount of Si of the adhesive layer surface after peeling the release liner is 1.0 atom% or less as measured by X-ray photoelectron spectroscopy.

14. The adhesive tape according to claim 1, wherein The number of particles of 0.30 μm or more in the adhesive tape in the adhesive tape peeling evaluation is 50 or less.

15. The adhesive tape according to claim 14, wherein The number of particles of more than or equal to 0.15 μm and less than 0.30 μm in the adhesive tape in the adhesive tape peeling evaluation is 1500 or less.

16. The adhesive tape according to any one of claims 1 to 15, wherein The adhesive tape is used for circuit surface protection of a semiconductor wafer.

17. The adhesive tape according to any one of claims 1 to 15, wherein The adhesive tape is used for surface protection of an optical product or an optical glass product.

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