Adhesive tape for semiconductor processing

Abstract

To provide an adhesive tape for semiconductor processing with excellent heat resistance that can suppress warpage of semiconductor wafers and adhesive tape for semiconductor processing and void formation in an adhesive layer, even when used in semiconductor manufacturing processes that include heating processes at 200°C or higher.SOLUTION: An adhesive tape 100 for semiconductor processing has an adhesive layer 20, a relaxation layer 30, and a base material 10, in this order. An outgassing of the relaxation layer is 4000 μg / g or less, and a stress relaxation rate is 70% or more. A thermal shrinkage of the base material is 3.0% or less.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an adhesive tape for semiconductor processing.

Background Art

[0002] Power semiconductors such as insulated gate bipolar transistors (IGBTs) are widely used for purposes including power conversion and motor control. Power semiconductors are large in size, and in order to improve device characteristics, the back surface thereof may be ground until the thickness becomes 100 µm or less. A power semiconductor is produced, for example, by attaching a back grind tape to a wafer, grinding the wafer, and then performing a back metal process of forming a metal layer by sputtering or vapor deposition to provide an electrode (Patent Document 1). Since the back metal process is performed in a high vacuum and a high temperature region of 200°C or higher, thinly ground semiconductor wafers may warp and crack. In addition, an ultraviolet curable adhesive is used for back grind tapes so that the tape can be peeled off lightly after the back grinding process. In a vacuum and high temperature environment, voids may occur in the adhesive layer of ultraviolet curable adhesives.

Prior Art Literature

Patent Literature

[0003]

Patent Document 1

Summary of the Invention

Problem to be Solved by the Invention

[0004] The present invention has been made to solve the above conventional problems, and an object of the present invention is to provide an adhesive tape for semiconductor processing having excellent heat resistance.

Means for Solving the Problem

[0005] 1. The semiconductor processing adhesive tape according to an embodiment of the present invention comprises, in this order, an adhesive layer, a relaxation layer, and a substrate. The outgassing amount of the relaxation layer is 4000 μg / g or less, and the stress relaxation rate is 70% or more. The thermal shrinkage rate of the substrate is 3.0% or less. 2. In the semiconductor processing adhesive tape described in 1. above, the composition forming the relaxation layer includes a base polymer, and this base polymer may be a polymer obtained by polymerizing a monomer composition having an acrylic acid content of 5 mol% or less. 3. In the semiconductor processing adhesive tape described in 2. above, the composition forming the relaxation layer may include a polymer obtained by addition polymerization of a compound having a polymerizable carbon-carbon double bond to the base polymer. 4. In the semiconductor processing adhesive tape described in 3. above, the amount of the polymerizable carbon-carbon double bond compound added may be 5 mol% or less. 5. In the semiconductor processing adhesive tape described in any of items 1 to 4 above, the composition forming the relaxation layer comprises a base polymer, and this base polymer may be a polymer obtained by polymerizing a monomer composition having a butyl acrylate content of 50 mol% or more. 6. In the semiconductor processing adhesive tape described in any of items 1 to 5 above, the adhesive layer may be a layer formed of an ultraviolet-curable adhesive. 7. In the adhesive tape for semiconductor processing described in any of items 1 to 6 above, the tensile modulus of the relaxation layer may be 0.1 MPa or higher. 8. In the semiconductor processing adhesive tape described in any of items 1 to 7 above, the semiconductor processing adhesive tape may be used in the backgrinding process. 9. In the semiconductor processing adhesive tape described in any of items 1 to 8 above, the semiconductor processing adhesive tape may be used in a semiconductor manufacturing process that includes a vacuum and a heating step of 200°C or higher. [Effects of the Invention]

[0006] According to embodiments of the present invention, a heat-resistant adhesive tape for semiconductor processing can be provided. The adhesive tape for semiconductor processing according to embodiments of the present invention can suppress warping of the semiconductor wafer and the adhesive tape for semiconductor processing, as well as the generation of voids in the adhesive layer, even when used in a semiconductor manufacturing process that includes a vacuum and high-temperature (e.g., 200°C or higher) heating process. [Brief explanation of the drawing]

[0007] [Figure 1] This is a schematic cross-sectional view of an adhesive tape for semiconductor processing according to one embodiment of the present invention. [Modes for carrying out the invention]

[0008] A. Overall structure of adhesive tape for semiconductor processing Figure 1 is a schematic cross-sectional view of an adhesive tape for semiconductor processing according to an embodiment of the present invention. The adhesive tape 100 for semiconductor processing comprises a base material 10, a relaxation layer 30, and an adhesive layer 20 in this order. The base material 10 has a thermal shrinkage rate of 3.0% or less. The relaxation layer 30 has an outgassing amount of 4000 μg / g or less and a stress relaxation rate of 70% or more. By providing such a base material 10 and relaxation layer 30, an adhesive tape for semiconductor processing with excellent heat resistance can be provided. An adhesive tape for semiconductor processing having such a base material and relaxation layer can suppress warping even when it is attached to a thinly ground semiconductor wafer and placed in a high-temperature environment (e.g., 200°C or higher). Furthermore, even when an ultraviolet-curable adhesive is used as the adhesive composition for forming the adhesive layer, the generation of voids can be suppressed. Therefore, for example, after being attached to a semiconductor wafer and undergoing a back-grinding process, it can be subjected to a vacuum and high-temperature (e.g., 200°C or higher) heating process (e.g., a back-metaling process) without being replaced with another adhesive sheet or support. In the illustrated example, the substrate 10 is a single layer, but it may be a laminate of two or more layers. The adhesive tape for semiconductor processing may have a separator on the outside of the adhesive layer to protect the adhesive layer until it is put into use.

[0009] The relaxation layer 30 has an outgassing amount of 4000 μg / g or less, preferably 3800 μg / g or less, more preferably 3100 μg / g or less, even more preferably 3000 μg / g or less, and particularly preferably 2800 μg / g or less. If the outgassing amount is within the above range, the generation of voids in the adhesive layer can be suppressed, and an adhesive tape for semiconductor processing with excellent heat resistance can be provided. A lower outgassing amount is preferable, for example, 1300 μg / g or more. In this specification, the outgassing amount of the relaxation layer refers to the sum of the outgassing amount of organic components and the outgassing amount of water. In this specification, the outgassing amount of organic components refers to the outgassing amount measured by the following method: 5 cm from a laminate in which separators are laminated on both sides of a relaxation layer with a thickness of 50 μm 2 A 1cm x 5cm section is cut out, the separators on both sides are removed to create an evaluation sample, and it is weighed. Next, the evaluation sample is placed in a vial and sealed tightly. Then, the vial containing the evaluation sample is heated using a headspace sampler (HSS), 1 mL of the heated gas is collected and injected into a gas chromatograph (GC), and the total outgassing amount (μg / g) is measured. In this specification, the outgassing amount of water is measured from a laminate with separators laminated on both sides of a 50 μm thick relaxation layer over a 10 cm period. 2 This refers to the moisture content measured by the Karl Fischer method of evaluation samples obtained by cutting out two 1cm x 5cm samples and peeling off the separator from both sides of the relaxation layer.

[0010] The stress relaxation rate of the relaxation layer 30 is 70% or more, preferably 71% or more, more preferably 75% or more, even more preferably 78% or more, and particularly preferably 80% or more. The stress relaxation rate of the relaxation layer is preferably 95% or less. If the stress relaxation rate is within the above range, even when placed in a high-temperature environment, the thermal shrinkage of the substrate can be mitigated and the occurrence of warping can be suppressed. In this specification, the stress relaxation rate refers to the value calculated from the test force measured by the following method using the following formula. A relaxation layer (thickness 20 μm) is formed between a pair of polyethylene terephthalate (PET) separators and aged in a dryer at 50°C for 48 hours. After that, the relaxation layer sandwiched between the separators is cut to a size of 50 mm in length and 30 mm in width. Next, the separators are peeled off and rolled up so that no air bubbles are trapped inside, and a rod-shaped sample of 30 mm in length and 1.13 mm in diameter is prepared. A rod-shaped sample is stretched to 50% using a tensile testing machine (for example, ORIENTEC RTC-1150A) under the conditions of a measurement temperature of 22 degrees Celsius, a chuck distance of 10 mm, and a speed of 10 mm / min. The sample is then fixed in this stretched state for 600 seconds. The stress relaxation rate is calculated from each test force (N) using the following formula. Stress relaxation rate = ((Test force at initial 50% tensile strength) - (Test force after fixing for 600 seconds)) / (Test force at initial 50% tensile strength) × 100

[0011] The thermal shrinkage rate of the base material 10 is 3.0% or less, preferably 2.5% or less, more preferably 2.0% or less, even more preferably 1.5% or less, and particularly preferably 1.0% or less. The smaller the thermal shrinkage rate of the base material, the better, for example, 0.1% or more. If the thermal shrinkage rate of the base material is within the above range, it is possible to provide an adhesive tape for semiconductor processing that suppresses warping even when placed in a high-temperature environment and has excellent heat resistance. In this specification, the thermal shrinkage rate refers to the value calculated by the following method. A film (10cm x 10cm) to be used as a base material is left standing at 25°C for 3 minutes and the initial length is measured. Next, the film is placed in a heating device and heated from 25°C to 200°C at a rate of 20°C / min and held at 200°C for 10 minutes. Next, it is cooled to 25°C at a rate of -20°C / min. After that, the length after heating is measured and the shrinkage rate is calculated from the following formula. Shrinkage rate (%) = 100 - ((Length after heating) / (Initial length) × 100)

[0012] The thickness of the semiconductor processing adhesive tape in the embodiment of the present invention can be set to any appropriate thickness. Preferably, the thickness of the semiconductor processing adhesive tape is 70 μm to 900 μm, more preferably 80 μm to 800 μm, and even more preferably 90 μm to 750 μm.

[0013] B. Base material As described above, the thermal shrinkage rate of the substrate is 3.0% or less. If the thermal shrinkage rate of the substrate is 3.0% or less, it is possible to provide an adhesive tape for semiconductor processing that suppresses warping and has excellent heat resistance. The preferred range for the heat absorption rate of the substrate is as described above.

[0014] The substrate can be composed of any suitable resin. Specific examples of resins constituting the substrate include polyester resins such as polyethylene naphthalate (PEN), polybutylene terephthalate (PBT), and polybutylene naphthalate (PBN); polyolefin resins such as ethylene-vinyl acetate copolymer, ethylene-methyl methacrylate copolymer, polyethylene, polypropylene, and ethylene-propylene copolymer; polyvinyl alcohol, polyvinylidene chloride, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, polyamide, polyimide, celluloses, fluororesins, polyethers, polystyrene resins such as polystyrene; polycarbonate, polyethersulfone, and polyetheretherketone. A polyester resin is preferred, and polyethylene naphthalate is more preferred. Using these resins, a substrate that can suppress warping even when exposed to high-temperature environments can be formed. Furthermore, since these resins transmit ultraviolet light, an adhesive layer can be formed using an ultraviolet-curing adhesive to provide a semiconductor processing adhesive tape with easy peelability.

[0015] The base material may further contain other components within a range that does not impair the effects of the present invention. Examples of the other components include antioxidants, ultraviolet absorbers, light stabilizers, heat stabilizers and the like. The types and amounts of the other components can be any appropriate amounts depending on the purpose.

[0016] The thickness of the base material is preferably 30 μm to 200 μm, more preferably 40 μm to 180 μm, and still more preferably 45 μm to 180 μm. When the thickness of the base material falls within the above range, the occurrence of warpage can be suppressed even when the base material is placed in a high temperature environment.

[0017] C. Stress relaxation layer As described above, the relaxation layer has an outgas amount of 4000 μg / g or less and a stress relaxation rate of 70% or more. The pressure-sensitive adhesive tape for semiconductor processing having such a relaxation layer can alleviate thermal shrinkage of the base material and suppress the occurrence of warpage even when placed in a high temperature environment. Furthermore, even when an ultraviolet-curable pressure-sensitive adhesive is used as the pressure-sensitive adhesive layer, the occurrence of voids can be suppressed. As a result, a pressure-sensitive adhesive tape for semiconductor processing having excellent heat resistance can be provided.

[0018] The tensile modulus of the relaxation layer is preferably 0.06 MPa or higher, more preferably 0.1 MPa or higher, and even more preferably 0.12 MPa or higher. The tensile modulus of the relaxation layer is preferably 1.1 MPa or lower. If the tensile modulus is within the above range, the occurrence of warping can be suppressed. In this specification, the tensile modulus refers to the value measured by the following method. A relaxation layer (thickness 20 μm) is formed between a pair of polyethylene terephthalate (PET) separators and aged in a dryer at 50°C for 48 hours. After that, the relaxation layer sandwiched between the separators is cut to a size of 50 mm in length and 30 mm in width. Next, the separators are peeled off, and the sample is rolled up so as not to contain air bubbles to prepare a rod-shaped sample of 30 mm in length and 1.13 mm in diameter. The SS curve of the rod-shaped sample is measured using a tensile testing machine (for example, ORIENTEC, product name: RTC-1150A) under the conditions of a measurement temperature of 22°C, a chuck distance of 10 mm, and a speed of 10 mm / min. The initial modulus of elasticity is determined from the rise of the SS curve, and this value is taken as the tensile modulus of elasticity of the relaxation layer.

[0019] The composition forming the relaxation layer (hereinafter also referred to as the relaxation layer forming composition) contains any suitable base polymer. Preferably, a (meth)acrylic polymer is used as the base polymer. Using a (meth)acrylic polymer makes it possible to provide an adhesive tape for semiconductor processing with excellent heat resistance. Furthermore, the storage modulus and tensile modulus of the relaxation layer can be adjusted to appropriate values. In this specification, "(meth)acrylic" refers to acrylic and / or methacrylic.

[0020] C-1. (Meth)acrylic polymer (Meth)acrylic polymers are polymers obtained by polymerizing a monomer composition containing any suitable (meth)acrylic monomer. Any suitable (meth)acrylic monomer can be used as the (meth)acrylic monomer. Typically, alkyl (meth)acrylates can be used. Specific examples of alkyl (meth)acrylates 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, isooctyl (meth)acrylate, and (meth) Examples of C1-20 alkyl esters of (meth)acrylate include nonyl acrylate, isononyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, undecyl (meth)acrylate, dodecyl (meth)acrylate, tridecyl (meth)acrylate, tetradecyl (meth)acrylate, pentadecyl (meth)acrylate, hexadecyl (meth)acrylate, heptadecyl (meth)acrylate, octadecyl (meth)acrylate, nonadecyl (meth)acrylate, and eicosyl (meth)acrylate. Alkyl (meth)acrylate may be used alone or in combination of two or more types.

[0021] For the purpose of modifying cohesiveness, heat resistance, crosslinkability, etc., other monomer components copolymerizable with the above (meth)acrylic monomers may be used as needed. Examples of such monomer components include: carboxyl group-containing monomers such as acrylic acid and methacrylic acid; acid anhydride monomers such as maleic anhydride and eicotanoic anhydride; hydroxyl group-containing monomers such as hydroxyethyl (meth)acrylate and hydroxypropyl (meth)acrylate; sulfonic acid group-containing monomers such as styrene sulfonic acid and allyl sulfonic acid; (N-substituted) amide monomers such as (meth)acrylamide and N,N-dimethyl(meth)acrylamide; aminoalkyl (meth)acrylate monomers such as aminoethyl (meth)acrylate; alkoxyalkyl (meth)acrylate monomers such as methoxyethyl (meth)acrylate; maleimide monomers such as N-cyclohexyl maleimide and N-isopropyl maleimide; and N-methylitaconimide and N-ethylitaconimide. Examples include itacolinimide monomers such as: succinimide monomers; vinyl monomers such as vinyl acetate, vinyl propionate, N-vinylpyrrolidone, and methylvinylpyrrolidone; 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 and polypropylene glycol (meth)acrylate; acrylic ester monomers having heterocycles, halogen atoms, silicon atoms, etc., such as tetrahydrofurfuryl (meth)acrylate, fluorine (meth)acrylate, and silicone (meth)acrylate; olefin monomers such as isoprene, butadiene, and isobutylene; and vinyl ether monomers such as vinyl ether. These monomer components may be used individually or in combination of two or more.

[0022] The acrylic acid content of the monomer composition is preferably 5 mol% or less, more preferably 4 mol% or less, and even more preferably 3 mol% or less. If the acrylic acid content of the monomer composition is within the above range, the amount of outgassing in the relaxation layer, particularly the amount of outgassing due to moisture, can be reduced. The acrylic acid content of the monomer composition may be, for example, 0 mol%, meaning the monomer composition does not contain acrylic acid.

[0023] The monomer composition preferably contains butyl acrylate. Using a monomer composition containing butyl acrylate reduces the amount of outgassing in the relaxation layer and provides an adhesive tape for semiconductor processing with excellent heat resistance. The butyl acrylate content in the monomer composition is preferably 50 mol% or more, more preferably 60 mol% to 99 mol%, and even more preferably 70 mol% to 97 mol%. If the butyl acrylate content is within the above range, the amount of outgassing in the relaxation layer can be further reduced.

[0024] The monomer composition preferably further comprises a hydroxyl group-containing (meth)acrylic monomer. The inclusion of the hydroxyl group-containing monomer yields a (meth)acrylic polymer having hydroxyl groups, and these hydroxyl groups can serve as introduction points for any suitable substituents. Furthermore, the content of the hydroxyl group-containing monomer in the monomer composition is preferably 0.1 mol% to 8 mol%, more preferably 1 mol% to 7.5 mol%. If the content of the hydroxyl group-containing monomer is within the above range, the addition polymerization of compounds having polymerizable carbon-carbon double bonds, as described later, can be successfully carried out.

[0025] Any suitable monomer can be used as the hydroxyl group-containing monomer. Examples include 2-hydroxymethyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 3-hydroxypropyl acrylate, 4-hydroxybutyl acrylate, 2-hydroxymethyl methacrylate, 2-hydroxyethyl methacrylate, and N-(2-hydroxyethyl)acrylamide. Preferably, 2-hydroxymethyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxymethyl methacrylate, and 2-hydroxyethyl methacrylate are used. These monomers may be used individually or in combination of two or more.

[0026] The content of ethyl acrylate and methyl acrylate in the monomer composition is preferably 5 mol% or less, more preferably 4 mol% or less, and even more preferably 3 mol% or less. If the content of ethyl acrylate and methyl acrylate in the monomer composition is within the above range, the amount of outgassing in the relaxation layer, especially the amount of outgassing due to moisture, can be reduced. The content of ethyl acrylate and methyl acrylate in the monomer composition may be, for example, 1 mol% or more, or the content of ethyl acrylate and methyl acrylate in the monomer composition may be 0 mol%, that is, the monomer composition may not contain ethyl acrylate and methyl acrylate.

[0027] In one embodiment, the monomer composition preferably contains butyl acrylate, a hydroxyl group-containing monomer, and at least one monomer selected from the group consisting of butyl methacrylate, methyl methacrylate, ethyl acrylate, isobutyl acrylate, isobutyl methacrylate, and isoamyl acrylate, such that the total amount of these monomer components is 100 mol%. By using a combination of these monomer components, it is possible to further reduce outgassing and provide an adhesive tape for semiconductor processing that can suppress the occurrence of warping.

[0028] In one embodiment, the relaxation layer forming composition (the resulting relaxation layer) includes a polymer obtained by addition polymerization of a compound having a polymerizable carbon-carbon double bond to the base polymer (hereinafter also referred to as a polymer having a polymerizable carbon-carbon double bond). When the relaxation layer includes a polymer having a polymerizable carbon-carbon double bond, the occurrence of warping can be further suppressed. The polymerizable carbon-carbon double bond may be added to the side chains of the base polymer, added to the terminals, or added to both the side chains and the terminals.

[0029] Polymers having polymerizable carbon-carbon double bonds in their side chains or terminals can be obtained by any suitable method. For example, they can be obtained by an addition reaction between the base polymer and a compound having polymerizable carbon-carbon double bonds. Specifically, a base polymer having constituent units derived from a monomer having any suitable functional group is polymerized in any suitable solvent, and then the functional group of the base polymer is reacted with a compound having polymerizable carbon-carbon double bonds that can react with the functional group to obtain a polymer having polymerizable carbon-carbon double bonds. The amount of the compound having polymerizable carbon-carbon double bonds to be reacted is used so as to be equimolar or less to the number of moles of the functional group of the base polymer. If the amount of the compound having polymerizable carbon-carbon double bonds exceeds the number of moles of the functional group of the base polymer, the amount of outgassing from organic components may increase. Any suitable solvent can be used as the solvent, for example, various organic solvents such as ethyl acetate, methyl tyl ketone, and toluene.

[0030] When reacting a base polymer with a compound having a polymerizable carbon-carbon double bond as described above, it is preferable that both the base polymer and the compound having a polymerizable carbon-carbon double bond have functional groups that can react with each other. Examples of functional group combinations include carboxyl group / epoxy group, carboxyl group / aziridine group, and hydroxyl group / isocyanate group. Among these functional group combinations, the combination of a hydroxyl group and an isocyanate group is preferred due to the ease of reaction tracking.

[0031] Examples of compounds having the polymerizable carbon-carbon double bond mentioned above include 2-isocyanate ethyl methacrylate, methacryloisocyanate, 2-methacryloyloxyethyl isocyanate (2-isocyanate ethyl methacrylate), and m-isopropenyl-α,α-dimethylbenzyl isocyanate.

[0032] The amount of polymerizable carbon-carbon double bond compound added to the base polymer is preferably 5 mol% or less, more preferably 4 mol% or less, and even more preferably 3 mol% or less. If the amount added exceeds 5 mol%, the amount of outgassing, especially outgassing from organic components, increases, and void formation may not be sufficiently suppressed.

[0033] C2. Crosslinking agent The relaxation layer forming composition preferably further contains a crosslinking agent. Examples of crosslinking agents include isocyanate-based crosslinking agents, epoxy-based crosslinking agents, aziridine-based crosslinking agents, and chelate-based crosslinking agents. The content ratio of the crosslinking agent is preferably 0.01 to 10 parts by weight, more preferably 0.02 to 5 parts by weight, and even more preferably 0.025 to 0.5 parts by weight, per 100 parts by weight of the base polymer (or polymer having polymerizable carbon-carbon double bonds if such polymer has polymerizable carbon-carbon double bonds) contained in the relaxation layer forming composition. If the crosslinking agent content is within the above range, the occurrence of warping can be suppressed. If the crosslinking agent content is less than 0.01 parts by weight, the composition may become sol-like and may not be able to form a relaxation layer. If the crosslinking agent content exceeds 10 parts by weight, the ability to follow the irregularities on the semiconductor wafer surface may decrease.

[0034] In one embodiment, an isocyanate-based crosslinking agent is preferably used. Isocyanate-based crosslinking agents are preferred because they can react with a variety of functional groups. Particularly preferred is a crosslinking agent having three or more isocyanate groups.

[0035] C-3. Additives The relaxation layer may contain any suitable additives as needed. Examples of additives include catalysts (e.g., platinum catalysts), tackifiers, plasticizers, pigments, dyes, fillers, antioxidants, conductive materials, UV absorbers, light stabilizers, release modifiers, softeners, surfactants, flame retardants, and solvents.

[0036] In one embodiment, the relaxation layer may be formed from an ultraviolet-curable composition. If the relaxation layer-forming composition is an ultraviolet-curable composition, the composition further comprises a photopolymerization initiator. Any suitable initiator can be used as the photopolymerization initiator. Examples of photopolymerization initiators include acylphosphine oxide-based photopolymerization initiators such as ethyl 2,4,6-trimethylbenzylphenylphosphine and (2,4,6-trimethylbenzoyl)-phenylphosphine oxide; α-ketol compounds such as 4-(2-hydroxyethoxy)phenyl(2-hydroxy-2-propyl)ketone, α-hydroxy-α,α'-dimethylacetophenone, 2-methyl-2-hydroxypropiophenone, and 1-hydroxycyclohexylphenylketone; acetophenone compounds such as methoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxyacetophenone, and 2-methyl-1-[4-(methylthio)-phenyl]-2-morpholinopropane-1; benzoin ether compounds such as benzoin ethyl ether, benzoin isopropyl ether, and anisoin methyl ether; ketal compounds such as benzyldimethyl ketal; and aromatic compounds such as 2-naphthalenesulfonyl chloride. Sulfonyl chloride compounds; photoactive oxime compounds such as 1-phenone-1,1-propanedione-2-(o-ethoxycarbonyl)oxime; benzophenone compounds such as benzophenone, benzoylbenzoic acid, and 3,3'-dimethyl-4-methoxybenzophenone; thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 2,4-dichlorothioxanthone, 2,4-diethylthioxanthone Examples include thioxanthone compounds such as santhone and 2,4-diisopropylthioxanthone; camphorquinone; halogenated ketones; acylphosphonates; and α-hydroxyacetophenones such as 2-hydroxy-1-(4-(4-(2-hydroxy-2-methylpropionyl)benzyl)phenyl-2-methylpropane-1. Preferably, acetophenone compounds can be used. One photopolymerization initiator may be used alone, or two or more may be used in combination.

[0037] The photopolymerization initiator can be used in any appropriate amount. The content of the photopolymerization initiator is preferably 0.5 to 20 parts by weight, and more preferably 0.5 to 10 parts by weight, per 100 parts by weight of the base polymer (or, if a compound having a polymerizable carbon-carbon double bond is added, the polymer having a polymerizable carbon-carbon double bond). If the content of the photopolymerization initiator is less than 0.5 parts by weight, curing may not be sufficient upon UV irradiation. If the content of the photopolymerization initiator exceeds 10 parts by weight, the storage stability of the relaxation layer forming composition may decrease.

[0038] The thickness of the relaxation layer can be set to any appropriate value. For example, it is 20 μm to 500 μm, preferably 30 μm to 400 μm, and more preferably 40 μm to 300 μm. If the thickness of the relaxation layer is within the above range, it is possible to provide an adhesive tape for semiconductor processing that reduces thermal shrinkage of the substrate and suppresses the occurrence of warping. Furthermore, it is possible to provide an adhesive tape for semiconductor processing that has excellent ability to fill in irregularities on the surface of semiconductor wafers.

[0039] D.Adhesive layer The adhesive layer is formed using any suitable adhesive composition. In one embodiment, the adhesive layer composition (the resulting adhesive layer) includes an ultraviolet-curable adhesive. When an ultraviolet-curable adhesive is included, an adhesive tape can be provided that has excellent adhesion to the adherend before ultraviolet irradiation and excellent release properties after ultraviolet irradiation. Furthermore, because the above-mentioned substrate and relaxation layer are provided, the generation of voids can be suppressed even when subjected to vacuum and high-temperature heating processes.

[0040] D-1. UV-curing adhesive Any suitable adhesive can be used as the UV-curing adhesive. For example, it may be an adhesive to which UV-curable monomers and / or oligomers have been added to any suitable adhesive such as acrylic adhesives, rubber adhesives, silicone adhesives, or polyvinyl ether adhesives, or it may be an adhesive using a polymer having polymerizable carbon-carbon double bonds in its side chains or terminals as the base polymer.

[0041] When using an adhesive that utilizes a polymer having polymerizable carbon-carbon double bonds in its side chains or terminals, the base polymer used is a polymer that has polymerizable carbon-carbon double bonds in its side chains or terminals and is also adhesive. Examples of such polymers include polymers in which polymerizable carbon-carbon double bonds have been introduced into resins such as (meth)acrylic resins, vinyl alkyl ether resins, silicone resins, polyester resins, polyamide resins, urethane resins, and styrene-diene block copolymers. Preferably, a (meth)acrylic polymer in which polymerizable carbon-carbon double bonds have been introduced into a (meth)acrylic resin is used. When a (meth)acrylic polymer is used, the storage modulus and tensile modulus of the adhesive layer can be easily adjusted, and an adhesive tape with an excellent balance between adhesive strength and release properties can be obtained. Furthermore, contamination of the adherend by components derived from the adhesive can be reduced.

[0042] Any suitable (meth)acrylic resin can be used as the (meth)acrylic resin. Examples of (meth)acrylic resins include polymers obtained by polymerizing a monomer composition containing one or more esters of acrylic acid or methacrylic acid having linear or branched alkyl groups.

[0043] The linear or branched alkyl groups are preferably alkyl groups having 30 or fewer carbon atoms, more preferably alkyl groups having 1 to 20 carbon atoms, and even more preferably alkyl groups having 4 to 18 carbon atoms. Specific examples of alkyl groups include methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, t-butyl group, isobutyl group, amyl group, isoamyl 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, tetradecyl group, stearyl group, octadecyl group, dodecyl group, and the like.

[0044] The monomer composition forming the (meth)acrylic resin may contain any other suitable monomers. Other monomers include, for example, 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; 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, 12-hydroxylauryl (meth)acrylate, and 4-hydroxypropyl (meth)acrylate. Examples of functional group-containing monomers include hydroxyl group-containing monomers such as roxymethylcyclohexyl)-methyl acrylate, 2-hydroxyethyl vinyl ether, 4-hydroxybutyl vinyl ether, and diethylene glycol monovinyl ether; sulfonic acid group-containing monomers such as styrene sulfonic acid, allyl sulfonic acid, 2-(meth)acrylamide-2-methylpropanesulfonic acid, (meth)acrylamidepropanesulfonic acid, sulfopropyl (meth)acrylate, and (meth)acryloyloxynaphthalenesulfonic acid; and phosphate group-containing monomers such as 2-hydroxyethyl acryloyl phosphate. When functional group-containing monomers are included, (meth)acrylic resins that readily incorporate polymerizable carbon-carbon double bonds can be obtained. The content of the functional group-containing monomer is preferably 4 to 30 parts by weight, and more preferably 6 to 20 parts by weight, per 100 parts by weight of the total monomers in the monomer composition.

[0045] Other monomers may be used, such as polyfunctional monomers. When polyfunctional monomers are used, the cohesive force, heat resistance, and adhesiveness of the adhesive can be improved. In addition, since the amount of low molecular weight components in the adhesive layer is reduced, an adhesive tape that is less likely to contaminate the adherend can be obtained. Examples of polyfunctional monomers include hexanediol (meth)acrylate, (poly)ethylene glycol di(meth)acrylate, (poly)propylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, pentaerythritol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, epoxy (meth)acrylate, polyester (meth)acrylate, and urethane (meth)acrylate. The content of the polyfunctional monomer is preferably 1 to 100 parts by weight, more preferably 5 to 50 parts by weight, per 100 parts by weight of the total monomers in the above monomer composition.

[0046] The weight-average molecular weight of the (meth)acrylic resin is preferably 300,000 or more, more preferably 500,000 or more, and even more preferably 800,000 to 3,000,000. Within this range, bleeding of low molecular weight components can be prevented, and a low-contamination adhesive tape can be obtained. The molecular weight distribution (weight-average molecular weight / number-average molecular weight) of the (meth)acrylic resin is preferably 1 to 20, and more preferably 3 to 10. By using a (meth)acrylic resin with a narrow molecular weight distribution, bleeding of low molecular weight components can be prevented, and a low-contamination adhesive tape can be obtained. The weight-average molecular weight and number-average molecular weight can be determined by gel permeation chromatography (solvent: tetrahydrofuran, polystyrene equivalent).

[0047] Polymers having polymerizable carbon-carbon double bonds in their side chains or terminals can be obtained by any suitable method. For example, they can be obtained by reacting (e.g., condensation reaction, addition reaction) a resin obtained by any suitable polymerization method with a compound having polymerizable carbon-carbon double bonds. Specifically, when using (meth)acrylic resins, a (meth)acrylic resin (polymer) having constituent units derived from monomers having any suitable functional groups can be polymerized in any suitable solvent, and then the functional groups of the acrylic resin can be reacted with a compound having polymerizable carbon-carbon double bonds that can react with the functional groups to obtain the above resin. The amount of the compound having polymerizable carbon-carbon double bonds to be reacted is preferably 4 to 30 parts by weight, more preferably 4 to 20 parts by weight, per 100 parts by weight of the above resin. Any suitable solvent can be used as the solvent, for example, various organic solvents such as ethyl acetate, methyl tyl ketone, and toluene.

[0048] When a resin and a compound having a polymerizable carbon-carbon double bond are reacted as described above, it is preferable that both the resin and the compound having a polymerizable carbon-carbon double bond have functional groups that can react with each other. Examples of functional group combinations include carboxyl group / epoxy group, carboxyl group / aziridine group, and hydroxyl group / isocyanate group. Among these functional group combinations, the combination of a hydroxyl group and an isocyanate group is preferred due to the ease of reaction tracking.

[0049] Examples of compounds having the polymerizable carbon-carbon double bond mentioned above include 2-isocyanate ethyl methacrylate, methacryloisocyanate, 2-methacryloyloxyethyl isocyanate (2-isocyanate ethyl methacrylate), and m-isopropenyl-α,α-dimethylbenzyl isocyanate.

[0050] When using an adhesive containing UV-curable monomers and / or oligomers, any suitable monomer or oligomer can be used as the UV-curable monomer and / or oligomer. Examples of UV-curable monomers include urethane (meth)acrylate, trimethylolpropane tri(meth)acrylate, tetramethylolmethane tetra(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol monohydroxypenta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, and 1,4-butanediol di(meth)acrylate. Examples of UV-curable oligomers include urethane-based oligomers, polyether-based oligomers, polyester-based oligomers, polycarbonate-based oligomers, and polybutadiene-based oligomers. Preferably, oligomers with a molecular weight of about 100 to 30000 are used. Monomers and oligomers may be used individually or in combination of two or more.

[0051] Monomers and / or oligomers may be used in any appropriate amount depending on the type of adhesive used. For example, 5 to 500 parts by weight, more preferably 40 to 150 parts by weight, are used per 100 parts by weight of the base polymer constituting the adhesive.

[0052] D-2. Photopolymerization Initiator Any suitable initiator can be used as the photopolymerization initiator. Examples of photopolymerization initiators include acylphosphine oxide-based photopolymerization initiators such as ethyl 2,4,6-trimethylbenzylphenylphosphine and (2,4,6-trimethylbenzoyl)-phenylphosphine oxide; α-ketol compounds such as 4-(2-hydroxyethoxy)phenyl(2-hydroxy-2-propyl)ketone, α-hydroxy-α,α'-dimethylacetophenone, 2-methyl-2-hydroxypropiophenone, and 1-hydroxycyclohexylphenylketone; acetophenone compounds such as methoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxyacetophenone, and 2-methyl-1-[4-(methylthio)-phenyl]-2-morpholinopropane-1; benzoin ether compounds such as benzoin ethyl ether, benzoin isopropyl ether, and anisoin methyl ether; ketal compounds such as benzyldimethyl ketal; and aromatic compounds such as 2-naphthalenesulfonyl chloride. Sulfonyl chloride compounds; photoactive oxime compounds such as 1-phenone-1,1-propanedione-2-(o-ethoxycarbonyl)oxime; benzophenone compounds such as benzophenone, benzoylbenzoic acid, and 3,3'-dimethyl-4-methoxybenzophenone; thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 2,4-dichlorothioxanthone, 2,4-diethylthioxanthone Examples include thioxanthone compounds such as santhone and 2,4-diisopropylthioxanthone; camphorquinone; halogenated ketones; acylphosphonates; and α-hydroxyacetophenones such as 2-hydroxy-1-(4-(4-(2-hydroxy-2-methylpropionyl)benzyl)phenyl-2-methylpropane-1. Preferably, acetophenone compounds can be used. One photopolymerization initiator may be used alone, or two or more may be used in combination.

[0053] Commercially available photopolymerization initiators may be used. Examples include Omnirad 127, Omnirad 369, and Omnirad 651 from IGM Resins.

[0054] The photopolymerization initiator can be used in any appropriate amount. The content of the photopolymerization initiator is preferably 0.5 to 20 parts by weight, and more preferably 0.5 to 10 parts by weight, per 100 parts by weight of the UV-curable adhesive. If the content of the photopolymerization initiator is less than 0.5 parts by weight, the adhesive may not cure sufficiently when irradiated with UV light. If the content of the photopolymerization initiator exceeds 10 parts by weight, the storage stability of the adhesive may decrease.

[0055] D-3. Additives The above adhesive layer-forming composition may optionally contain any suitable additives. Examples of such additives include crosslinking agents, catalysts (e.g., platinum catalysts), tackifiers, plasticizers, pigments, dyes, fillers, antioxidants, conductive materials, ultraviolet absorbers, light stabilizers, release modifiers, softeners, surfactants, flame retardants, and solvents.

[0056] The thickness of the adhesive layer can be set to any appropriate value. Preferably, the thickness of the adhesive layer is 2 μm to 500 μm, more preferably 3 μm to 300 μm, and even more preferably 5 μm to 250 μm. If the thickness of the adhesive layer is within the above range, it can exhibit sufficient adhesion to the adherend.

[0057] E. Method for manufacturing adhesive tape for semiconductor processing The semiconductor processing adhesive tape according to the embodiment of the present invention can be manufactured by any suitable method. For example, it can be obtained by applying a relaxation layer forming composition or an adhesive solution (UV-curable adhesive) to a separator, drying them to form a relaxation layer or an adhesive layer on the separator, and then sequentially bonding them to a substrate. Alternatively, the semiconductor processing adhesive tape can be obtained by applying the relaxation layer forming composition and the adhesive layer forming composition to a substrate, drying them, etc. Various methods can be used to apply the adhesive layer forming composition, such as bar coater coating, air knife coating, gravure coating, gravure reverse coating, reverse roll coating, lip coating, die coating, dip coating, offset printing, flexographic printing, and screen printing. Any suitable drying method can be used.

[0058] F. Applications of adhesive tapes for semiconductor processing The semiconductor processing adhesive tape according to the embodiment of the present invention can be suitably used in semiconductor manufacturing processes. Preferably, it is used as a backgrind tape. As described above, since the semiconductor processing adhesive tape according to the embodiment of the present invention has excellent heat resistance, when used in a semiconductor manufacturing process that includes a heating step after the backgrinding step, it can be used in the heating step without having to replace it with another adhesive sheet or support.

[0059] As described above, the semiconductor processing adhesive tape of the embodiment of the present invention has excellent heat resistance. Therefore, even when it is attached to a semiconductor wafer and subjected to a backgrinding process, and then subjected to a process in which it is heated in a vacuum and at a high temperature of 200°C or higher (for example, a back metal process), it can suppress the occurrence of warping and cracking of the semiconductor wafer. Furthermore, even when the adhesive layer is formed using an ultraviolet-curable adhesive, the occurrence of voids can be suppressed. Therefore, after the backgrinding process and before being subjected to a process in which it is heated in a vacuum and at a high temperature of 200°C or higher, it is possible to subject it to a process in which it is heated in a vacuum and at a high temperature of 200°C or higher without replacing it with another heat-resistant adhesive tape or another support. Therefore, semiconductor wafers such as power semiconductors can be manufactured efficiently. In this specification, vacuum means a pressure below atmospheric pressure. [Examples]

[0060] The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. In the examples, unless otherwise specified, "parts" and "%" are based on weight.

[0061] [Synthesis Example 1] Synthesis of Polymer1 Polymer 1 was synthesized using the monomer components listed in Table 1. Specifically, a monomer composition was prepared by mixing 30 parts by weight of 2-ethylhexyl acrylate (2EHA), 70 parts by weight of methyl methacrylate (MA), 10 parts by weight of acrylic acid (AA), 0.2 parts by weight of polymerization initiator (benzoyl peroxide (BPO)), and solvent (toluene). This monomer composition was placed in a 1 L round-bottom separable flask into a polymerization apparatus equipped with a separable cover, separatory funnel, thermometer, nitrogen inlet tube, Liebig condenser, vacuum seal, stirring rod, and stirring blade, and nitrogen was purged at room temperature for 2 hours while stirring. Subsequently, polymerization was carried out at 60°C for 8 hours while stirring under nitrogen inflow to obtain a resin (Polymer 1) solution. The obtained resin solution was cooled to room temperature.

[0062] [Table 1]

[0063] [Synthesis Example 2] Synthesis of Polymer2 Polymer 2 was synthesized using the monomer components listed in Table 1. Specifically, a monomer composition was prepared by mixing 50 parts by weight of butyl acrylate (BA), 50 parts by weight of ethyl acrylate (EA), 5 parts by weight of acrylic acid (AA), 1 part by weight of 2-hydroxyethyl acrylate, 0.1 parts by weight of polymerization initiator (benzoyl peroxide (BPO)), and solvent (toluene). This monomer composition was placed in a 1 L round-bottom separable flask into a polymerization apparatus equipped with a separable cover, separatory funnel, thermometer, nitrogen inlet tube, Liebig condenser, vacuum seal, stirring rod, and stirring blade, and nitrogen was purged at room temperature for 2 hours while stirring. Subsequently, polymerization was carried out at 60°C for 8 hours while stirring under nitrogen inflow to obtain a resin (Polymer 2) solution. The obtained resin solution was cooled to room temperature.

[0064] [Synthesis Example 3] Synthesis of Polymer3 Polymer 3 was synthesized using the monomer components listed in Table 1. Specifically, a monomer composition was prepared by mixing 100 parts by weight of butyl acrylate (BA), 3 parts by weight of acrylic acid (AA), 0.2 parts by weight of polymerization initiator (2,2'-azobis-isobutyronitrile (AIBN)), and solvent (ethyl acetate). This monomer composition was placed in a 1 L round-bottom separable flask into a polymerization apparatus equipped with a separable cover, separatory funnel, thermometer, nitrogen inlet tube, Liebig condenser, vacuum seal, stirring rod, and stirring blade, and nitrogen was purged at room temperature for 2 hours while stirring. Subsequently, polymerization was carried out at 60°C for 8 hours while stirring under nitrogen inflow to obtain a resin (Polymer 3) solution. The obtained resin solution was cooled to room temperature.

[0065] [Synthesis Example 4] Synthesis of Polymer4 Polymer 4 was synthesized using the monomer components listed in Table 1. Specifically, a monomer composition was prepared by mixing 100 parts by weight of butyl acrylate (BA), 7 parts by weight of 2-hydroxyethyl acrylate (HEA), 0.3 parts by weight of polymerization initiator (2,2'-azobis-isobutyronitrile (AIBN)), and solvent (thiel acetate). This monomer composition was placed in a 1 L round-bottom separable flask into a polymerization apparatus equipped with a separable cover, separatory funnel, thermometer, nitrogen inlet tube, Liebig condenser, vacuum seal, stirring rod, and stirring blade, and nitrogen was purged at room temperature for 2 hours while stirring. Subsequently, polymerization was carried out at 60°C for 8 hours while stirring under nitrogen inflow to obtain a resin (Polymer 4) solution. The obtained resin solution was cooled to room temperature.

[0066] [Synthesis Example 5] Synthesis of Polymer5 Polymer 5 was synthesized using the monomer components listed in Table 1. Specifically, a monomer composition was prepared by mixing 100 parts by weight of butyl acrylate (BA), 37 parts by weight of butyl methacrylate (BMA), 6 parts by weight of 2-hydroxyethyl acrylate (HEA), 0.3 parts by weight of polymerization initiator (2,2'-azobis-isobutyronitrile (AIBN)), and solvent (thiel acetate). This monomer composition was placed in a 1 L round-bottom separable flask into a polymerization apparatus equipped with a separable cover, separatory funnel, thermometer, nitrogen inlet tube, Liebig condenser, vacuum seal, stirring rod, and stirring blade. The mixture was stirred and nitrogen purged at room temperature for 2 hours. Subsequently, polymerization was carried out at 60°C for 8 hours while stirring under nitrogen inflow, yielding a resin (Polymer 5) solution. The resulting resin solution was cooled to room temperature.

[0067] [Synthesis Example 6] Synthesis of Polymer6 Polymer 6 was synthesized using the monomer components listed in Table 1. Specifically, a monomer composition was prepared by mixing 100 parts by weight of butyl acrylate (BA), 37 parts by weight of butyl methacrylate (BMA), 6 parts by weight of 2-hydroxyethyl acrylate (HEA), 0.3 parts by weight of polymerization initiator (2,2'-azobis-isobutyronitrile (AIBN)), and solvent (thiel acetate). This monomer composition was placed in a 1 L round-bottom separable flask into a polymerization apparatus equipped with a separable cover, separatory funnel, thermometer, nitrogen inlet tube, Liebig condenser, vacuum seal, stirring rod, and stirring blade, and nitrogen was purged at room temperature for 2 hours while stirring. Subsequently, polymerization was carried out at 60°C for 8 hours while stirring under nitrogen inflow to obtain a resin solution. The obtained resin solution was cooled to room temperature. Next, 2 parts by weight of 2-isocyanatoethyl methacrylate (manufactured by Showa Denko, trade name "Karens MOI"), a compound having a polymerizable carbon-carbon double bond, was added to the cooled resin solution. Furthermore, 0.1 parts by weight of dibutyltin IV dilaurate (manufactured by Wako Pure Chemical Industries, Ltd.) was added, and the mixture was stirred at 50°C for 24 hours under an air atmosphere to obtain a resin (Polymer 6) solution.

[0068] [Synthesis Example 7] Synthesis of Polymer7 Polymer 7 was synthesized using the monomer components listed in Table 1. Specifically, a monomer composition was prepared by mixing 100 parts by weight of butyl acrylate (BA), 37 parts by weight of butyl methacrylate (BMA), 6 parts by weight of 2-hydroxyethyl acrylate (HEA), 0.3 parts by weight of polymerization initiator (2,2'-azobis-isobutyronitrile (AIBN)), and solvent (thiel acetate). This monomer composition was placed in a 1 L round-bottom separable flask into a polymerization apparatus equipped with a separable cover, separatory funnel, thermometer, nitrogen inlet tube, Liebig condenser, vacuum seal, stirring rod, and stirring blade, and nitrogen was purged at room temperature for 2 hours while stirring. Subsequently, polymerization was carried out at 60°C for 8 hours while stirring under nitrogen inflow to obtain a resin solution. The obtained resin solution was cooled to room temperature. Next, 5 parts by weight of 2-isocyanatoethyl methacrylate (manufactured by Showa Denko, trade name "Karens MOI"), a compound having a polymerizable carbon-carbon double bond, was added to the cooled resin solution. Furthermore, 0.1 parts by weight of dibutyltin IV dilaurate (manufactured by Wako Pure Chemical Industries, Ltd.) was added, and the mixture was stirred at 50°C for 24 hours under an air atmosphere to obtain the resin (Polymer 7) solution.

[0069] [Synthesis Example 8] Synthesis of Polymer8 Polymer 8 was synthesized using the monomer components listed in Table 1. Specifically, a monomer composition was prepared by mixing 100 parts by weight of butyl acrylate (BA), 37 parts by weight of butyl methacrylate (BMA), 6 parts by weight of 2-hydroxyethyl acrylate (HEA), 0.3 parts by weight of polymerization initiator (2,2'-azobis-isobutyronitrile (AIBN)), and solvent (thiel acetate). This monomer composition was placed in a 1 L round-bottom separable flask into a polymerization apparatus equipped with a separable cover, separatory funnel, thermometer, nitrogen inlet tube, Liebig condenser, vacuum seal, stirring rod, and stirring blade, and nitrogen was purged at room temperature for 2 hours while stirring. Subsequently, polymerization was carried out at 60°C for 8 hours while stirring under nitrogen inflow to obtain a resin solution. The obtained resin solution was cooled to room temperature. Next, 8 parts by weight of 2-isocyanatoethyl methacrylate (manufactured by Showa Denko, trade name "Karens MOI"), a compound having a polymerizable carbon-carbon double bond, was added to the cooled resin solution. Furthermore, 0.1 parts by weight of dibutyltin IV dilaurate (manufactured by Wako Pure Chemical Industries, Ltd.) was added, and the mixture was stirred at 50°C for 24 hours under an air atmosphere to obtain the resin (Polymer 8) solution.

[0070] [Manufacturing Examples 1-10] Preparation of Relaxation Layer Forming Compositions A polymer (resin solution) and a crosslinking agent (manufactured by Nippon Polyurethane Industry Co., Ltd., product name "Coronate L") were mixed in the quantities shown in Table 3 to obtain a relaxation layer forming composition.

[0071] [Manufacturing Example 11] Preparation of an adhesive composition A monomer composition was prepared by mixing 100 parts by weight of butyl acrylate (BA), 7 parts by weight of 2-hydroxyethyl acrylate (HEA), 0.3 parts by weight of polymerization initiator (2,2'-azobis-isobutyronitrile (AIBN)), and solvent (thiel acetate). The monomer composition was placed in a 1 L round-bottom separable flask into a polymerization apparatus equipped with a separable cover, separatory funnel, thermometer, nitrogen inlet tube, Liebig condenser, vacuum seal, stirring rod, and stirring blade. The mixture was stirred and nitrogen purged at room temperature for 2 hours. Subsequently, polymerization was carried out at 60°C for 8 hours while stirring under nitrogen inflow to obtain a resin solution. The obtained resin solution was cooled to room temperature. Next, 5 parts by weight of 2-isocyanatoethyl methacrylate (manufactured by Showa Denko, trade name "Karens MOI"), a compound having a polymerizable carbon-carbon double bond, was added to the cooled resin solution. Furthermore, 0.1 parts by weight of dibutyltin IV dilaurate (manufactured by Wako Pure Chemical Industries, Ltd.) was added, and the mixture was stirred at 50°C for 24 hours under an air atmosphere to obtain a resin solution containing a resin having a polymerizable carbon double bond. To 100 parts by weight of the obtained resin solution, 0.50 parts by weight of a crosslinking agent (manufactured by Nippon Polyurethane Industry Co., Ltd., trade name "Coronate L") and 1 part by weight of a photopolymerization initiator (manufactured by Ciba Japan, trade name "Irgacure 369") were added and mixed to obtain an adhesive composition.

[0072] [Example 1] A relaxation layer-forming composition 1 was applied to the corona-treated surface of a 50 μm thick polyethylene naphthalate (PEN) film (manufactured by Teijin Film Solutions Co., Ltd., product name "Teonex® Film Q51"), which had been corona-treated on one side. The film was then dried in a dryer at 120°C for 3 minutes to form a 50 μm thick relaxation layer. Separately, the adhesive layer-forming composition obtained in Manufacturing Example 11 was applied to the release treatment side of a polyethylene terephthalate (PET) separator (manufactured by Mitsubishi Chemical Corporation, product name "Diafoil MRF38"), and dried in a dryer at 120°C for 3 minutes to form an adhesive layer with a thickness of 6 μm. Next, the relaxation layer and the adhesive layer were bonded together using a hand roller, ensuring no air bubbles were trapped. Then, the material was left in a dryer set to 50°C for 48 hours in a light-shielded environment. After being removed from the dryer, the adhesive tape was obtained.

[0073] [Examples 2-8] An adhesive tape was obtained in the same manner as in Example 1, except that the relaxation layer forming composition was as shown in Table 3.

[0074] (Comparative Example 1) An adhesive tape was obtained in the same manner as in Example 1, except that the relaxation layer forming composition was as shown in Table 3.

[0075] (Comparative Example 2) The adhesive tape was obtained except that polyethylene terephthalate (PET) film (manufactured by Toray Industries, Ltd., product name "Lumirror #50 ES-10") was used instead of polyethylene naphthalate film, and the relaxation layer forming composition was as described in Table 3.

[0076] (Comparative Example 3) An adhesive tape was obtained in the same manner as in Example 1, except that the relaxation layer forming composition was as shown in Table 3.

[0077] <Rating> The adhesive tapes, substrates, and relaxation layer-forming compositions obtained in the examples and comparative examples were evaluated as follows. The results are shown in Table 3. 1. Heat shrinkage rate The films (10 cm x 10 cm) used as substrates in the examples and comparative examples were left to stand at 25°C for 3 minutes, and the initial sample length was measured. Next, the films were placed in a heating device and heated from 25°C to 200°C at a rate of 20°C / min, and held at 200°C for 10 minutes. Then, they were cooled to 25°C at a rate of -20°C / min. The length after heating was then measured, and the shrinkage rate was calculated using the following formula. Shrinkage rate (%) = 100 - ((Length after heating) / (Initial length) × 100)

[0078] 2. Outgassing (organic components) The relaxation layer-forming compositions used in the examples and comparative examples were applied to the release surface of a PET separator (manufactured by Mitsubishi Chemical Corporation, product name "Diafoil MRF38"), and dried on the PET separator in a dryer at 120°C for 3 minutes to form a relaxation layer with a thickness of 50 μm. Next, the release surface side of another PET separator (manufactured by Mitsubishi Chemical Corporation, product name "Diafoil MRF38") was bonded to the side of the relaxation layer that was not in contact with the PET separator, without introducing any air bubbles, and left in a dryer set to 50°C for 48 hours to obtain a laminate. 5cm from the laminate 2A 1cm x 5cm section was cut out, the separators on both sides were removed to create an evaluation sample, and the evaluation sample was weighed. Next, the evaluation sample was placed in a vial and sealed tightly. Then, the vial containing the evaluation sample was heated using a headspace sampler (HSS) under the following conditions. 1 mL of the heated gas was collected and injected into a gas chromatograph (GC) for measurement to determine the total outgassing amount (μg / g). <Analyzer> HSS: Manufactured by Shimadzu Corporation, product name "HS-20" GC: Manufactured by Shimadzu Corporation, product name "QP2010Ultra" <Condition> < <hss>> Oven temperature: 200℃ Heating time: 15 minutes Sample loop temperature: 240℃ Transfer line temperature: 250℃ Pressurization time: 0.50 minutes Loop filling time: 0.50 minutes Loop equilibrium time: 0.10 minutes Injection time: 0.50 minutes < <gc>> Column: DB-17 (0.250mmφ × 30m, df = 0.5μm) Column temperature: 40°C (3 mins) → 10°C / min → 280°C (13 mins) Column pressure: 49.7 kPa (40°C) Carrier gas: He (1.0 mL / min (40°C), constant linear velocity mode) Linear speed: 36.1cm / sec Inlet temperature: 250℃ Injection method: Split (20:1) Detector: FID Detector temperature: 250℃

[0079] 3. Outgassing (moisture) The outgassing (moisture content) of the relaxation layer was measured using the Karl Fischer method. The relaxation layer-forming compositions used in the examples and comparative examples were applied to the release surface of a PET separator (manufactured by Mitsubishi Chemical Corporation, product name "Diafoil MRF38"), and dried on the PET separator in a dryer at 120°C for 3 minutes to form a relaxation layer with a thickness of 50 μm. Next, the release surface side of another PET separator (manufactured by Mitsubishi Chemical Corporation, product name "Diafoil MRF38") was bonded to the side of the relaxation layer that was not in contact with the PET separator, without introducing any air bubbles, and left in a dryer set to 50°C for 48 hours to obtain a laminate. The laminated material is 10cm 2 Two 1cm x 5cm samples were cut out, the separators on both sides were removed, and the samples were transferred to aluminum foil and weighed. The weighed samples were placed in a heating vaporizer (Mitsubishi Chemical Analytec Co., Ltd., product name "VA-200"), and the gas generated at 150°C was introduced into the titration cell of a coulometric titration moisture meter (Mitsubishi Chemical Analytec Co., Ltd., product name "CA-200") to measure the moisture content (μg / g).

[0080] 4. Tensile modulus A relaxation layer (20 μm thick) was formed between a pair of polyethylene terephthalate (PET) separators (manufactured by Mitsubishi Chemical Corporation, product name "Diafoil MRF38") using the compositions used in each example and comparative example, and aged in a dryer at 50°C for 48 hours. After that, the relaxation layer sandwiched between the separators was cut to a size of 50 mm in length and 30 mm in width. Next, the separators were peeled off, and the material was rolled up to prevent air bubbles from forming, and a rod-shaped sample with a length of 30 mm and a diameter of 1.13 mm was prepared. The tensile strength curve (SS) of the rod-shaped sample was measured using a tensile testing machine (ORIENTEC, product name: RTC-1150A) under the conditions of a measurement temperature of 22 degrees Celsius, a chuck distance of 10 mm, and a speed of 10 mm / min. The initial modulus of elasticity was determined from the rise of the SS curve, and this value was defined as the tensile modulus of the relaxation layer. Three measurements were performed, and the average value was used as the tensile modulus of elasticity. The tensile modulus of elasticity was measured before UV irradiation and after UV irradiation (50 mW / cm²). 2 , 20 seconds, 1000mJ / cm 2 Measurements were taken for each of the following steps.

[0081] 5. Stress relaxation rate A relaxation layer (20 μm thick) was formed between a pair of polyethylene terephthalate (PET) separators (manufactured by Mitsubishi Chemical Corporation, product name "Diafoil MRF38") using the compositions used in each example and comparative example, and aged in a dryer at 50°C for 48 hours. After that, the relaxation layer sandwiched between the separators was cut to a size of 50 mm in length and 30 mm in width. Next, the separators were peeled off, and the material was rolled up to prevent air bubbles from forming, and a rod-shaped sample with a length of 30 mm and a diameter of 1.13 mm was prepared. Using a tensile testing machine (ORIENTEC, product name: "RTC-1150A"), a rod-shaped sample was stretched to 50% under the conditions of a measurement temperature of 22 degrees Celsius, a chuck distance of 10 mm, and a speed of 10 mm / min. The sample was then fixed in this stretched state for 600 seconds. The stress relaxation rate was calculated from each test force (N) using the following formula. Stress relaxation rate = ((Test force at initial 50% tensile strength) - (Test force after 600 seconds)) / (Test force at initial 50% tensile strength) × 100

[0082] 6. Amount of curvature The adhesive tapes obtained in the examples and comparative examples were attached to Si mirror wafers under the following conditions. Application device: DR 3000III (manufactured by Nitto Seiki) Application settings: 8 inches Adhesive tape: As shown in the examples and comparative examples. Attached wafer: 8-inch Si wafer (unground) Attachment table: 23℃ Application pressure: 0.4 MPa Pasting speed: 3mm / sec Cutter temperature: 180℃ Cutting speed: 200 mm / second Cutter blade: Art knife replacement blade XB10 (Olfa brand) Next, the side of the Si mirror wafer that did not have adhesive tape attached was ground using a backgrinding device (Disco Corporation, product name "DGP8760") under the conditions described in Table 2, to achieve a final finished thickness of 100 μm.

[0083] [Table 2]

[0084] The laminate of the ground wafer and adhesive tape was placed in an oven and heated at 200°C for 15 minutes, then cooled to room temperature and removed from the oven. The removed sample was placed on a flat table with the adhesive tape on top and the Si mirror wafer on the bottom (so that the Si mirror wafer was in contact with the table), and the center where the Si mirror wafer was in contact was defined as 0, and the height of the edges was measured as the amount of warpage. The portion with the maximum height was defined as the amount of warpage for each sample.

[0085] 7. Void The samples whose warping amount was measured were visually observed, the number of voids larger than 1 mm was counted, and they were evaluated according to the following criteria. ○: 0 voids △: 1 to 50 voids ×: More than 50 voids

[0086] 8. Peel strength and adhesive residue The sample from which the above-mentioned amount of warpage was measured was irradiated with ultraviolet light from the adhesive tape side under the following conditions. Next, the adhesive tape was peeled off using an adhesive application device (manufactured by Nitto Seiki Co., Ltd., product name "DR-9000", table temperature: 60℃, peeling speed: 3mm / sec). The surface of the Si mirror wafer to which the adhesive tape was attached was visually inspected after peeling, and × was used if there was adhesive residue, and ○ if there was no adhesive residue. <Ultraviolet irradiation conditions> UV irradiation device: Manufactured by Nitto Seiki Co., Ltd., product name: UM810 Light source: High-pressure mercury lamp Irradiation intensity: 50mW / cm 2 (Measuring instrument: Ushio Corporation, product name "Ultraviolet Irradiance Meter UT-101") Irradiation time: 20 seconds Total luminous intensity: 2000 mJ / cm² 2

[0087] [Table 3] [Industrial applicability]

[0088] The semiconductor processing adhesive tape of the present invention can also be suitably used in semiconductor wafer manufacturing processes that include a heating step of 200°C or higher. [Explanation of symbols]

[0089] 10 Base material 20 Adhesive layer 30 relaxation layer 100 Adhesive tapes for semiconductor processing< / gc> < / hss>

Claims

1. The structure comprises an adhesive layer, a relaxation layer, and a substrate in this order. The outgassing rate of the relaxation layer is 4000 μg / g or less, and the stress relaxation rate is 70% or more. An adhesive tape for semiconductor processing, wherein the thermal shrinkage rate of the substrate is 0.9% or less.

2. The semiconductor processing adhesive tape according to claim 1, wherein the composition forming the relaxation layer comprises a base polymer, and the base polymer is a polymer obtained by polymerizing a monomer composition having an acrylic acid content of 5 mol% or less.

3. The semiconductor processing adhesive tape according to claim 2, wherein the composition forming the relaxation layer includes a polymer obtained by addition polymerization of a compound having a polymerizable carbon-carbon double bond to the base polymer.

4. The semiconductor processing adhesive tape according to claim 3, wherein the amount of the polymerizable carbon-carbon double bond compound added is 5 mol% or less.

5. The semiconductor processing adhesive tape according to claim 1, wherein the composition forming the relaxation layer comprises a base polymer, and the base polymer is a polymer obtained by polymerizing a monomer composition having a butyl acrylate content of 50 mol% or more.

6. The adhesive tape for semiconductor processing according to claim 1, wherein the adhesive layer is formed of an ultraviolet-curing adhesive.

7. The adhesive tape for semiconductor processing according to claim 1, wherein the tensile modulus of the relaxation layer is 0.1 MPa or more.

8. A semiconductor processing adhesive tape according to any one of claims 1 to 7, used in a backgrinding process.

9. A semiconductor processing adhesive tape according to any one of claims 1 to 7, used in a semiconductor manufacturing process that includes a vacuum and a heating step of 200°C or higher.

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