Adhesive tape and processing method

Abstract

An adhesive tape comprising a substrate and an adhesive layer layered on at least one side of the substrate, wherein the adhesive layer contains a (meth)acrylic polymer having a carboxyl group, an amine compound having a secondary or higher amine group, and a photopolymerization initiator, the amine compound content is at least 0.1 parts by weight per 100 parts by weight of the (meth)acrylic polymer, and the acid value of the adhesive layer is at least 10 mg KOH / g.

Description

[Technical Field]

[0001] The present invention relates to an adhesive tape and a processing method using the same. [Background technology]

[0002] When semiconductor packages or semiconductor wafers (hereinafter also referred to as "adherends") are diced, a semiconductor wafer processing tape is attached to the adherend to temporarily fix the adherend during dicing. This prevents chips from flying off during dicing. After dicing, the semiconductor wafer processing tape is expanded, and the diced adherends are picked up (peeled off) from the semiconductor wafer processing tape.

[0003] The most commonly used semiconductor wafer processing tape is an adhesive tape in which an adhesive layer that cures when exposed to ultraviolet light is applied to a UV-transparent film substrate. In this UV-curable processing tape, the adhesive layer is irradiated with ultraviolet light after dicing to promote the curing reaction, thereby reducing the adhesive strength of the adhesive layer, making it easy to pick up the individual wafers.

[0004] During the pick-up, the individualized adherends are pushed up by a push-up pin from the back side of the adhesive tape that is not in contact with the adherend, and pick-up is performed. From the perspective of efficiently producing high-quality electronic components, it is required at this time to reduce adhesive residue of the adhesive tape on the adherend and to enable pick-up at a high yield even with a low pin height.

[0005] However, if the adhesive does not wet the adherend well when the adhesive tape is applied to the adherend, the adhesive will not be able to fully conform to uneven areas on the adherend, resulting in the formation of air bubbles. This can cause the adhesive to cure poorly due to oxygen inhibition during UV irradiation, resulting in the adhesive remaining uncured on the adherend. Furthermore, if the adhesive strength to the adherend is insufficient, cutting water can seep between the adherend and the adhesive tape during dicing, contaminating the adherend or even causing the individual pieces of the adherend to scatter.

[0006] Therefore, methods that can be considered include increasing the thickness of the adhesive layer to compensate for the adhesive's wettability to the adherend, adding low-molecular-weight components or tackifiers to increase adhesive strength, or lowering the elastic modulus of the adhesive layer to increase adhesive strength. However, in this case, the frictional heat generated by the rotation of the blade during dicing melts the adhesive, which can be scraped up and cause adhesive debris to adhere to the adherend. Furthermore, if the adhesive is cured by ultraviolet irradiation in a scraped-up state, the individualized adherends will be fixed to the adhesive tape, making pickup at low pin heights difficult. Even if pickup is possible, the adhesive itself may be destroyed due to inability to peel at the interface with the adherend, resulting in adhesive residue on the adherend.

[0007] As a method for suppressing such scraping up of the adhesive, Patent Document 1 discloses the use of an acrylic polymer and a urethane acrylate oligomer having three or more unsaturated bonds. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-013692 Summary of the Invention [Problem to be solved by the invention]

[0009] However, when using an acrylic polymer and a urethane acrylate oligomer with three or more unsaturated bonds, although the adhesive lift-up is suppressed, it has been found that the adhesive becomes too hard after UV irradiation. If the adhesive becomes too hard after UV irradiation, when the tape is pushed up from the back with a pin during pickup, the hardened adhesive cannot follow the deformation of the tape and cracks. Such adhesive cracking can actually cause adhesive residue.

[0010] Therefore, it has been considered to ensure wettability with the adherend by introducing carboxyl groups into the polymer and utilizing the polarity of the carboxyl groups. In this case, the more carboxyl groups there are, the higher the adhesive strength and wettability, which reduces the risk of chipping. However, the inventors' studies have revealed that the higher the carboxyl group content, the gradually lower the adhesive strength and worsen the wettability when stored in a high-temperature environment for a long period of time, increasing the risk of chipping.

[0011] The present invention has been made in consideration of the above-mentioned problems, and aims to provide an adhesive tape and processing method that has high adhesive strength before ultraviolet irradiation, low adhesive strength after ultraviolet irradiation, and exhibits little deterioration in adhesive strength even when stored for a long period of time in a high-temperature environment. [Means for solving the problem]

[0012] The present inventors have conducted extensive research to solve the above-mentioned problems, and as a result, have found that the above-mentioned problems can be solved by using an amine compound having a predetermined amount of secondary or higher amine groups, thereby completing the present invention.

[0013] That is, the present invention is as follows. [1] A substrate and an adhesive layer laminated on at least one surface of the substrate, The adhesive layer contains a (meth)acrylic polymer having a carboxyl group, an amine compound having a secondary or higher amine group, and a photopolymerization initiator, the content of the amine compound is 0.1 parts by weight or more relative to 100 parts by weight of the (meth)acrylic polymer, The acid value of the adhesive layer is 10 mgKOH / g or more. Adhesive tape. [2] the content of the amine compound is 15 parts by weight or less relative to 100 parts by weight of the (meth)acrylic polymer; The adhesive tape described in [1]. [3] The amine compound includes a cyclic amine compound. The adhesive tape according to [1] or [2]. [4] The cyclic amine compound includes an alicyclic amine. The adhesive tape according to [3]. [5] The cyclic amine compound includes 1,4-diazabicyclo[2,2,2]octane or a derivative thereof. The adhesive tape according to [3] or [4]. [6] The acid value of the adhesive layer is 100 mgKOH / g or less. The pressure-sensitive adhesive tape according to any one of [1] to [5]. [7] The (meth)acrylic polymer has a polymerizable double bond at the end and / or in the side chain. The pressure-sensitive adhesive tape according to any one of [1] to [6]. [8] The (meth)acrylic polymer has a structural unit represented by the following formula (1): The pressure-sensitive adhesive tape according to any one of [1] to [7]. [ka] (In the formula, R 1 represents an organic group having a polymerizable double bond, and R 2 represents a single bond or an organic group having 1 to 6 carbon atoms, and R 3 represents a hydrogen atom or a methyl group. [9] the adhesive layer contains an isocyanate compound, the content of the isocyanate compound is 4.0 parts by weight or less relative to 100 parts by weight of the (meth)acrylic polymer; The pressure-sensitive adhesive tape according to any one of [1] to [8].

[10] a bonding step of bonding the pressure-sensitive adhesive tape according to any one of [1] to [9] to an adherend; a dicing step of processing the adherend in a state where the adhesive tape and the adherend are stuck together; an ultraviolet irradiation step of irradiating the adhesive tape with ultraviolet light after the dicing step, The adherend is a semiconductor wafer, a semiconductor device, or various semiconductor packages. Processing method. [Effects of the Invention]

[0014] According to the present invention, it is possible to provide an adhesive tape and a processing method that have high adhesive strength before ultraviolet irradiation and low adhesive strength after ultraviolet irradiation, and that show little decrease in adhesive strength even when stored for a long period of time in a high-temperature environment. DETAILED DESCRIPTION OF THE INVENTION

[0015] The following describes in detail an embodiment of the present invention (hereinafter referred to as "the present embodiment"); however, the present invention is not limited to this embodiment, and various modifications are possible without departing from the spirit of the present invention.

[0016] In this embodiment, "(meth)acrylic" refers to both methacrylic and acrylic. Furthermore, "monomer" refers to a compound before polymerization, and "structural unit" refers to a repeating unit of a certain monomer in a polymer.

[0017] 1. Adhesive tape The adhesive tape of the present embodiment comprises a substrate and an adhesive layer laminated on at least one surface of the substrate, the adhesive layer containing a (meth)acrylic polymer having a carboxyl group (hereinafter also referred to as "(meth)acrylic polymer A"), an amine compound having a secondary or higher amine group (hereinafter also referred to as "amine compound B"), and a photopolymerization initiator, the content of amine compound B being 0.1 parts by weight or more relative to 100 parts by weight of (meth)acrylic polymer A, and the acid value of the adhesive layer being 10 mgKOH / g or more.

[0018] Carboxyl groups derived from the matrix polymer present in the adhesive layer of an adhesive tape can have the function of improving wettability to an adherend and improving adhesive strength before UV irradiation. However, it has been found that when an adhesive tape is stored in a high-temperature environment for a long period of time, reactions such as oxidation, esterification, and condensation of the carboxyl groups progress, resulting in a problem of a decrease over time in the adhesiveness derived from the carboxyl groups.

[0019] In contrast, in this embodiment, by using a (meth)acrylic polymer A having a carboxyl group in combination with an amine compound B having a predetermined amount of secondary or higher amine groups, the adhesive strength is high before UV irradiation and low after UV irradiation, and the adhesive strength can be prevented from decreasing even when stored for a long period of time in a high-temperature environment. This is thought to be because the amine groups of the amine compound B coordinate with the carboxyl groups of the (meth)acrylic polymer A, thereby suppressing the reaction of the carboxyl groups that causes the adhesive strength to decrease over time, but the mechanism of action is not limited to this. The adhesive tape of this embodiment will be described in detail below.

[0020] 1.1. Base material The material constituting the substrate is not particularly limited, and examples thereof include polyvinyl chloride, polyethylene terephthalate, ethylene-vinyl acetate copolymer, ethylene-acrylic acid-acrylic acid ester film, ethylene-ethyl acrylate copolymer, polyethylene, polypropylene, propylene-based copolymer, ethylene-acrylic acid copolymer, and ionomer resins obtained by crosslinking ethylene-(meth)acrylic acid copolymer, ethylene-(meth)acrylic acid-(meth)acrylic acid ester copolymer, or the like with metal ions. The material constituting the substrate may be one of these alone or two or more of these in combination. The substrate may also be a laminate of multiple layers of such materials.

[0021] The thickness of the substrate is preferably 10 to 500 μm, more preferably 50 to 200 μm, and even more preferably 70 to 150 μm. When the thickness of the substrate is within the above range, handleability is improved and costs tend to be reduced. Here, the thickness of the substrate means the total thickness when the substrate is composed of multiple layers.

[0022] In order to improve adhesion to the adhesive layer, the surface of the substrate that comes into contact with the adhesive layer may be subjected to a chemical or physical surface treatment, as necessary. Examples of such surface treatments include corona treatment, chromic acid treatment, ozone exposure, flame exposure, high-voltage shock exposure, and ionizing radiation treatment.

[0023] 1.2. Adhesive layer The adhesive layer is a layer laminated on at least one surface of the substrate, and contains a (meth)acrylic polymer A having a carboxyl group, an amine compound B having a secondary or higher amine group, and a photopolymerization initiator, and may also contain an isocyanate compound and other components as necessary.

[0024] 1.2.1. Acid number The acid value of the adhesive layer is 10 mgKOH / g or more, preferably 20 to 120 mgKOH / g, more preferably 25 to 100 mgKOH / g, and even more preferably 30 to 80 mgKOH / g. When the acid value of the adhesive layer is 10 mgKOH / g or more, the adhesive strength before UV irradiation is further improved. When the acid value of the adhesive layer is 120 mgKOH / g or less, the compatibility of the components is further improved, and the adhesive strength after UV irradiation tends to be further reduced. Furthermore, the reduced adhesive strength after UV irradiation tends to be further improved in chip pick-up efficiency. The acid value of the adhesive layer can be adjusted by the amount of (meth)acrylic polymer A and amine compound B used, which will be described later. The acid value of the adhesive layer can be measured by the method described in the examples.

[0025] Thickness The thickness of the adhesive layer is preferably 1.0 to 250 μm, more preferably 2.0 to 50 μm, and even more preferably 4.0 to 40 μm. When the thickness of the adhesive layer is 1.0 μm or more, the adhesive strength is further improved, and scattering of semiconductor chips separated by expanding tends to be suppressed. Furthermore, when the thickness of the adhesive layer is 250 μm or less, costs tend to be further reduced.

[0026] When used as an adhesive tape for semiconductor wafer processing, the total thickness of the adhesive tape is preferably 60 to 250 μm, more preferably 70 to 200 μm, and even more preferably 70 to 180 μm.

[0027] 1.2.3. (Meth)acrylic polymers containing carboxyl groups The (meth)acrylic polymer A having a carboxyl group contributes to improving adhesive strength before UV irradiation and reducing adhesive strength after UV irradiation. The (meth)acrylic polymer A may be used alone or in combination of two or more. Note that, in addition to the (meth)acrylic polymer A having a carboxyl group, the adhesive layer of the present embodiment may further contain a (meth)acrylic polymer not having a carboxyl group, as necessary.

[0028] The polymerization form of the (meth)acrylic polymer A is not particularly limited, and examples thereof include a homopolymer, a random copolymer, a block copolymer, and a graft copolymer. The polymerization form of the (meth)acrylic polymer A is also not particularly limited, and examples thereof include a linear polymer, a branched polymer, and a crosslinked polymer. A crosslinked or branched polymer may be a polymer in which some of the polymerizable double bonds of a linear polymer have been bonded by aging or the like.

[0029] The content of the (meth)acrylic polymer A is preferably 60 to 99 mass %, more preferably 70 to 99 mass %, and even more preferably 80 to 98 mass %, relative to the total amount of the adhesive layer. When the content of the (meth)acrylic polymer A is within the above range, the adhesive strength before UV irradiation tends to be further improved, and the adhesive strength after UV irradiation tends to be further reduced.

[0030] 1.2.3.1. Building blocks The structural units contained in the (meth)acrylic polymer A may include structural units derived from a (meth)acrylic monomer that is (meth)acrylic acid or a derivative thereof, as well as structural units derived from a monomer having a polymerizable double bond copolymerizable with the (meth)acrylic monomer.

[0031] The (meth)acrylic polymer A is not particularly limited as long as it is polymerized using a (meth)acrylic monomer as a base unit and has a carboxyl group at the end and / or side chain. The (meth)acrylic polymer A may also contain a reactive functional group other than a carboxyl group at the end and / or side chain. Examples of such reactive functional groups include, but are not limited to, functional groups containing a polymerizable double bond, such as a hydroxyl group, an epoxy group, a vinyl group, and a (meth)acryloyl group.

[0032] The monomer constituting the structural unit of the (meth)acrylic polymer A is not particularly limited, but examples thereof include aliphatic group-containing monomers, carboxyl group-containing monomers, acid anhydride monomers, hydroxyl group-containing monomers, sulfonic acid group-containing monomers, and phosphoric acid group-containing monomers. Among these, aliphatic group-containing monomers and carboxyl group-containing monomers are more preferred.

[0033] The aliphatic group-containing monomer is not particularly limited, and examples thereof include alkyl (meth)acrylates having a linear or branched alkyl group such as methyl, ethyl, n-propyl, isopropyl, n-butyl, t-butyl, isobutyl, amyl, isoamyl, hexyl, heptyl, cyclohexyl, 2-ethylhexyl, octyl, isooctyl, nonyl, isononyl, decyl, isodecyl, undecyl, lauryl, tridecyl, tetradecyl, stearyl, octadecyl, and dodecyl. These aliphatic group-containing monomers may be used alone or in combination of two or more.

[0034] The content of the structural units of the aliphatic group-containing monomer is preferably 55 to 95 parts by weight, more preferably 65 to 90 parts by weight, and even more preferably 75 to 85 parts by weight, relative to the total amount of the (meth)acrylic polymer A. When the content of the structural units of the aliphatic group-containing monomer is within the above range, the adhesive strength before UV irradiation is improved and the adhesive strength after UV irradiation is reduced, and the reduction in adhesive strength tends to be further suppressed even when the film is stored in a high-temperature environment for a long period of time.

[0035] The carboxyl group-containing monomer is not particularly limited, but examples thereof include acrylic acid, methacrylic acid, carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid, etc. These carboxyl group-containing monomers may be used alone or in combination of two or more.

[0036] The content of the structural unit of the carboxyl group-containing monomer is preferably 5 to 45 parts by weight, more preferably 10 to 35 parts by weight, and even more preferably 15 to 25 parts by weight, relative to the total amount of the (meth)acrylic polymer A. When the content of the structural unit of the carboxyl group-containing monomer is within the above range, the adhesive strength before UV irradiation is improved and the adhesive strength after UV irradiation is reduced, and the reduction in adhesive strength tends to be further suppressed even when the film is stored in a high-temperature environment for a long period of time.

[0037] The acid anhydride monomer is not particularly limited, but examples thereof include maleic anhydride, itaconic anhydride, etc. These acid anhydride monomers may be used alone or in combination of two or more.

[0038] The hydroxyl group-containing monomer is not particularly limited, but examples thereof include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 1-hydroxydecyl (meth)acrylate, 12-hydroxylauryl (meth)acrylate, and (4-hydroxymethylcyclohexyl)methyl (meth)acrylate. These hydroxyl group-containing monomers may be used alone or in combination of two or more.

[0039] The sulfonic acid group-containing monomer is not particularly limited, but examples thereof include styrenesulfonic acid, allylsulfonic acid, 2-(meth)acrylamido-2-methylpropanesulfonic acid, (meth)acrylamidopropanesulfonic acid, sulfopropyl (meth)acrylate, and (meth)acryloyloxynaphthalenesulfonic acid. These sulfonic acid group-containing monomers may be used alone or in combination of two or more.

[0040] The phosphate group-containing monomer is not particularly limited, but examples thereof include 2-hydroxyethyl acryloyl phosphate.

[0041] The (meth)acrylic polymer A preferably has a polymerizable double bond at the end and / or in the side chain, and more preferably has a structural unit represented by the following formula (1) as a structural unit having a polymerizable double bond introduced in the side chain. This allows the polymerization initiator to proceed with the polymerization reaction of the (meth)acrylic polymer A upon irradiation with ultraviolet light. The progress of the polymerization reaction of the (meth)acrylic polymer A in this way tends to reduce the adhesive strength after ultraviolet light irradiation and further reduce contamination of the adherend. [ka] (In the formula, R 1 represents an organic group having a polymerizable double bond, and R 2 represents a single bond or an organic group having 1 to 6 carbon atoms, and R 3 represents a hydrogen atom or a methyl group.

[0042] R 1 The organic group having a polymerizable double bond represented by the formula (I) is not particularly limited, but examples thereof include -CH2OC(=O)C(=CH2)CH3 and -CH2OC(=O)C(=CH2)H. 1 Examples of the group represented by the formula (I) include a residue formed after an epoxy compound having a polymerizable double bond is added to a carboxyl group.

[0043] R 2 The organic group having 1 to 6 carbon atoms represented by the formula (I) is not particularly limited, but examples thereof include linear, branched, or cyclic alkyl groups and alkyleneoxy groups.

[0044] R 2 When is a single bond, for example, a structural unit in which an epoxy compound having a polymerizable double bond is added to a structural unit derived from acrylic acid or methacrylic acid can be mentioned.

[0045] In order to make the (meth)acrylic polymer A have a polymerizable double bond in its side chain, as in the constitutional unit represented by formula (1), a method can be mentioned in which a modifying agent having a polymerizable double bond is reacted with a carboxyl group of a constitutional unit derived from a carboxyl group-containing monomer, a carboxyl anhydride group of a constitutional unit derived from an acid anhydride monomer, or a hydroxyl group of a constitutional unit derived from a hydroxyl group-containing monomer, which is contained in the (meth)acrylic polymer A before the introduction of the polymerizable double bond.

[0046] For example, by reacting an epoxy compound having a polymerizable double bond as a modifier with the (meth)acrylic polymer A, a polymerizable double bond can be introduced via an ester bond into a structural unit derived from a carboxyl group-containing monomer. As another example, by reacting an isocyanate compound having a polymerizable double bond as a modifier with the (meth)acrylic polymer A, a polymerizable double bond can be introduced via an amide bond into a structural unit derived from a carboxyl group-containing monomer.

[0047] The modifier is not particularly limited as long as it has a functional group that reacts with the functional group of the (meth)acrylic polymer A and has a polymerizable double bond, and examples thereof include an epoxy compound having a polymerizable double bond and an isocyanate compound having a polymerizable double bond.

[0048] The content of the structural unit having a polymerizable double bond as represented by formula (1) is preferably 2.5 to 25 mass %, more preferably 5.0 to 20 mass %, and even more preferably 7.5 to 15 mass %, relative to the total amount of the (meth)acrylic polymer A.

[0049] The content of the structural unit having a polymerizable double bond introduced therein is preferably 15 to 95 mol %, or may be 30 to 85 mol %, or 45 to 80 mol %, relative to the total amount of the structural units constituting the (meth)acrylic polymer A.

[0050] When the content of structural units incorporating polymerizable double bonds is 2.5% by mass or more or 15% by mole or more, the adhesive strength after UV irradiation is further reduced. UV irradiation sufficiently promotes the crosslinking reaction of the polymerizable double bonds of the (meth)acrylic polymer A, and curing shrinkage reduces the contact area with the adherend, tending to sufficiently reduce the adhesive strength. This facilitates peeling, tending to further improve pickup performance. Furthermore, even if unpolymerized monomers remain in the adhesive layer, they may be able to react with the double bonds of the (meth)acrylic polymer A upon UV irradiation, tending to further reduce adhesive residue. Furthermore, since the number of carboxyl groups is relatively low, the adhesive strength is also likely to be further reduced even when the adhesive is stored for a long period of time in a high-temperature environment.

[0051] In addition, by setting the content of structural units having polymerizable double bonds to 25% by mass or less or 95% by mole or less, the carboxyl group content is relatively high, which tends to further improve the adhesive strength before UV irradiation. In addition, by suppressing excessive crosslinking, the adhesive layer tends to be prevented from being unable to withstand the deformation of the adhesive tape caused by the pin being pushed up during pickup, which can lead to cracking in the shape of the pin and the resulting adhesive residue.

[0052] The content of the structural unit having a carboxyl group relative to the total amount of the structural units constituting the (meth)acrylic polymer A is preferably 5 to 85 mol %, or may be 15 to 70 mol %, or 25 to 55 mol %.

[0053] The double bond equivalent of the (meth)acrylic polymer A is preferably 500 to 2500 g / mol, more preferably 800 to 2000 g / mol, and even more preferably 1000 to 1800 g / mol.

[0054] By making the double bond equivalent of (meth)acrylic polymer A 500 g / mol or more, the adhesive strength before UV irradiation tends to be improved because the carboxyl group content is relatively high. In addition, excessive crosslinking can be suppressed, which tends to prevent the adhesive layer from being unable to withstand the deformation of the adhesive tape caused by the pin thrust during pickup, resulting in cracking in the shape of the pin and the resulting adhesive residue.

[0055] Furthermore, since the double bond equivalent of the (meth)acrylic polymer A is 2500 g / mol or less, the crosslinking reaction of the polymerizable double bonds of the (meth)acrylic polymer A proceeds sufficiently upon UV irradiation, and the contact area with the adherend is reduced due to cure shrinkage, which tends to sufficiently reduce the adhesive strength. This allows for easy peeling, which tends to further improve pickup performance. Furthermore, even if unpolymerized monomers remain in the adhesive layer, they may be able to react with the double bonds of the (meth)acrylic polymer A upon UV irradiation, which tends to further reduce adhesive residue. Furthermore, since the number of carboxyl groups is relatively low, the decrease in adhesive strength tends to be further suppressed even when the adhesive is stored for a long period of time in a high-temperature environment.

[0056] The "double bond equivalent" described in this specification is the amount of double bonds determined by measuring the iodine value in accordance with "Testing methods for acid value, saponification value, ester value, iodine value, hydroxyl value and unsaponifiable matter of chemical products" (JIS K 0070). Specifically, iodine monochloride solution was added to the sample to add to the double bonds, and excess I was titrated with sodium thiosulfate solution to determine the amount of double bonds using the following formula: A={(BC)×f×1.269} / S A: Iodine value B: Amount of sodium thiosulfate solution used in the blank test (mL) C: Amount of sodium thiosulfate solution used in titration (mL) f: Factor of sodium thiosulfate solution S: mass of sample (g)

[0057] In order to provide a polymerizable double bond at the end, one method is to modify either the polymerization initiation end and / or the polymerization termination end of the (meth)acrylic polymer A with a compound having a polymerizable double bond.

[0058] The acid value of the (meth)acrylic polymer A is preferably 10 to 1000 mgKOH / g, 20 to 500 mgKOH / g, 30 to 250 mgKOH / g, or 30 to 100 mgKOH / g. When the acid value of the (meth)acrylic polymer A is 10 mgKOH / g or more, the adhesive strength before UV irradiation tends to be further improved. When the acid value of the (meth)acrylic polymer A is 1000 mgKOH / g or less, the compatibility of the components is further improved, and the adhesive strength after UV irradiation tends to be further reduced.

[0059] 1.2.3.2. Weight average molecular weight The weight average molecular weight of the (meth)acrylic polymer A is preferably 1.0×10 5 ~2.0×10 6 and more preferably 2.0 × 10 5 ~1.0×10 6 , more preferably 2.5 × 10 5 ~8.0×10 5 is.

[0060] The weight average molecular weight of (meth)acrylic polymer A is 1.0 × 10 5 As a result of the above, the amount of high molecular weight components increases, and the higher the molecular weight, the more opportunities there are for one (meth)acrylic polymer A to polymerize with another (meth)acrylic polymer A via a polymerizable double bond, which tends to further reduce contamination.

[0061] The weight average molecular weight of (meth)acrylic polymer A is 2.0 × 10 6By satisfying the above condition, the (meth)acrylic polymer A is more mobile, increasing the opportunities for one (meth)acrylic polymer A to polymerize with another (meth)acrylic polymer A, which tends to further reduce contamination. Furthermore, the smaller the molecular weight, the lower the elastic modulus of the adhesive, which tends to further improve adhesive strength. Furthermore, since it has better conformability to the adherend and can conform to unevenness in the adherend, contamination due to poor UV curing caused by oxygen inhibition can be avoided. Furthermore, since soft adhesives are easily cured and shrink when exposed to UV light, the adhesive strength after curing can be sufficiently reduced, which tends to further improve pick-up properties.

[0062] The "weight average molecular weight" described in this specification is a molecular weight measured by dissolving a sample of (meth)acrylic polymer A in tetrahydrofuran using a gel permeation chromatograph analyzer based on a calibration curve of molecular weight converted into standard polystyrene.

[0063] Glass transition temperature The glass transition point of the (meth)acrylic polymer A is preferably -80 to 23°C, more preferably -70 to 10°C, and even more preferably -60 to 0°C. When the (meth)acrylic polymer A has a glass transition point of -80°C or higher, contamination tends to be further reduced. Furthermore, when the (meth)acrylic polymer A has a glass transition point of 23°C or lower, adhesion to adherends tends to be further improved. The glass transition point of the (meth)acrylic polymer A can be measured by differential scanning calorimetry (DSC) based on JIS K7121.

[0064] 1.2.4. Amine compounds with secondary or higher amine groups The amine compound B having a secondary or higher amine group can inhibit reactions such as oxidation, esterification, and condensation of the carboxyl group by coordinating with the carboxyl group derived from the (meth)acrylic polymer A, thereby inhibiting deterioration of adhesiveness over time. Note that the adhesive layer of the present embodiment may further contain a primary amine compound, if necessary, in addition to the amine compound B having a secondary or higher amine group.

[0065] The amine group possessed by the amine compound B is secondary or higher, preferably secondary or tertiary. By using an amine compound B having a secondary or higher amine group, the amine group in the amine compound B is more likely to coordinate with the carboxyl group in the (meth)acrylic polymer A than when only a primary amine compound is used, and the effect of suppressing a decrease in adhesive strength during high-temperature storage is significantly exhibited.

[0066] The amine compound B is not particularly limited, but examples thereof include chain amines and cyclic amines. Among these, cyclic amines are preferred. By using such an amine compound B, the nitrogen atom in the amine compound B is more likely to be coordinated to the carboxyl group of the (meth)acrylic polymer, and the decrease in adhesive strength during high-temperature storage tends to be more suppressed.

[0067] The chain amine is not particularly limited, but examples thereof include dibutylamine, diisobutylamine, dihexylamine, dioctylamine, bis(2-ethylhexyl)amine, diphenylamine, N-methylaniline, N-ethylaniline, tripropylamine, tributylamine, triisobutylamine, trihexylamine, trioctylamine, and tris(2-ethylhexyl)amine.

[0068] Examples of cyclic amines include alicyclic amines and aromatic amines. Examples of alicyclic amines include, but are not limited to, pyrrolidine, piperidine, morpholine, imidazoline; piperazine-based compounds such as piperazine, homopiperazine, 1-methylpiperazine, 2-methylpiperazine, 1-ethylpiperazine, 1,4-dimethylpiperazine, and 1-(2-aminoethyl)piperazine; tetrakis(1,2,2,6,6-pentamethyl-4-piperidyl)butane-1,2,3,4-tetracarboxylate, tetrakis(2,2,6,6-tetramethyl-4-piperidyl)butane-1,2,3,4-tetracarboxylate, and the like. Carboxylate, Bis(1,2,2,6,6-pentamethyl-4-piperidyl)sebacic acid, Bis(2,2,6,6-tetramethyl-4-piperidyl)sebacic acid, 1,2,2,6,6-pentamethyl-4-piperidyl methacrylate, 2,2,6,6-tetramethyl-4-piperidyl methacrylate, N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)hexane-1,6-diamine, Bis(1,2,2,6,6-pentamethyl-4-piperidyl)butyl(3,5-di-tert-butyl-4-hydroxybenzyl)methyl piperidyl compounds such as ronic acid; 1,4-diazabicyclo[2,2,2]octane, 2-methyl-1,4-diazabicyclo[2,2,2]octane, 1,4-diazabicyclo[2,2,2]octan-2-ol, 2-chloro-1,4-diazabicyclo[2,2,2]octane, 1,4-diazabicyclo[2,2,2]octane-2-methanol, 1,4-diazabicyclo[2,2,2]octane-2,5-dimethanol, 1,4-diazabicyclo[2,2,2]octane-2-carboxylic acid, 1,4-diazabicyclo[2,2,2] 1,4-diazabicyclo[2,2,2]octane compounds such as methyl octane-2-carboxylate, 1,4-diazabicyclo[2,2,2]oct-2-ene, 1,4-diazabicyclo[2,2,2]octa-2,5-diene, and 1,4-diazabicyclo[2,2,2]oct-ylmethyl-2-propenoate; 1,5-diazabicyclo[3,2,2]nonane, 1,4-diazabicyclo[3,2,2]nonane, 1,8-diazabicyclo[5,4,0]-7-undecene, and 1,5-diazabicyclo[4,3,0]-5-nonene.

[0069] The aromatic amine is not particularly limited, but examples thereof include pyrrole, pyridine, pyrimidine, pyrazine; imidazole, 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-phenylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl- ... imidazole compounds such as 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, and 2,3-dihydro-1H-pyrrolo[1,2-a]benzimidazole; and triazine compounds such as 1,3,5-triazine, 1,3,5-triazine-2-amine, 2,4-diamino-6-[2'-methylimidazolyl-(1')]ethyl-s-triazine, 2,4-diamino-6-[2'-undecylimidazolyl-(1')]ethyl-s-triazine, and 2,4-diamino-6-[2'-ethyl-4'-methylimidazolyl-(1')]ethyl-s-triazine.

[0070] Among these, alicyclic amines are preferred, piperidyl compounds and 1,4-diazabicyclo[2,2,2]octane compounds are more preferred, 1,4-diazabicyclo[2,2,2]octane or its derivatives are even more preferred, and compounds having a hydroxyl group, such as 1,4-diazabicyclo[2,2,2]octane-2-methanol, are particularly preferred. Since the nitrogen atom of such amine compound B protrudes outward from the amine compound B, coordination with the carboxyl group is further improved. Therefore, the use of such amine compound B tends to suppress a decrease in adhesive strength during high-temperature storage. Furthermore, the presence of a hydroxyl group or the like tends to further improve compatibility with other components.

[0071] In this embodiment, the term "derivative" refers to a compound in which a hydrogen atom of a certain compound is substituted with a substituent. The substituent is not particularly limited, but examples thereof include a halogen group, a hydroxyl group, an amino group, a nitro group, and a carboxyl group.

[0072] The number of amino groups in amine compound B is preferably 1 to 4, more preferably 1 to 3, and even more preferably 1 to 2. When the number of amino groups is within the above range and the amine compound B is a low molecular weight compound, the coordination ability to carboxyl groups is further improved, and the decrease in adhesive strength during high-temperature storage tends to be suppressed.

[0073] The content of amine compound B is 0.1 part by weight or more, preferably 0.1 to 15 parts by weight, more preferably 0.5 to 15.0 parts by weight, even more preferably 0.5 to 10.0 parts by weight, and even more preferably 0.5 to 5.0 parts by weight, relative to 100 parts by weight of (meth)acrylic polymer A. When the content of amine compound B is 0.1 part by weight or more, the coordination effect of amine compound B to the carboxyl groups of (meth)acrylic polymer A is fully exerted, and a decrease in adhesive strength during high-temperature storage is further suppressed. Furthermore, when the content of amine compound B is 15 parts by weight or less, adhesive strength before UV irradiation is further improved and contamination of the adherend by amine compound B tends to be further suppressed.

[0074] 1.2.5. Photoinitiators When the adhesive layer is irradiated with ultraviolet light, the photopolymerization initiator generates active species such as radicals, which then promotes polymerization of the polymerizable double bonds in (meth)acrylic polymer A. This hardens the adhesive layer, reducing its viscosity and improving its pick-up properties.

[0075] Such photopolymerization initiators are not particularly limited, but examples thereof include alkylphenone-based photopolymerization initiators, acylphosphine oxide-based photopolymerization initiators, thioxanthone-based photopolymerization initiators, aromatic ketones, aromatic onium salt compounds, organic peroxides, thio compounds (such as thiophenyl group-containing compounds), α-aminoalkylphenone compounds, hexaarylbiimidazole compounds, ketoxime ester compounds, borate compounds, azinium compounds, metallocene compounds, active ester compounds, compounds having a carbon-halogen bond, and alkylamine compounds.

[0076] Among these, alkylphenone-based photopolymerization initiators such as acetophenone, acetophenone benzyl ketal, 1-hydroxycyclohexyl phenyl ketone, and 2,2-dimethoxy-2-phenylacetophenone are preferred. By using such photopolymerization initiators, polymerization tends to proceed more appropriately.

[0077] The content of the photopolymerization initiator is preferably 0.5 to 10 parts by weight, more preferably 0.5 to 7.5 parts by weight, and even more preferably 0.5 to 5.0 parts by weight, relative to 100 parts by weight of the (meth)acrylic polymer A. When the content of the photopolymerization initiator is 0.5 parts by weight or more, the adhesive layer tends to be sufficiently cured even when the illuminance or irradiation amount of ultraviolet light is low. Furthermore, when the content of the photopolymerization initiator is 10 parts by weight or less, the risk of the photopolymerization initiator causing contamination tends to be reduced.

[0078] 1.2.6. Isocyanate compounds The adhesive layer may contain an isocyanate compound. This tends to further improve the cohesive strength of the adhesive layer. The number of isocyanate groups per molecule of the isocyanate compound is preferably 2 to 6, and more preferably 2 to 4. By using such an isocyanate compound, multiple (meth)acrylic polymers A can also be crosslinked by the isocyanate compound, so the cohesive strength of the adhesive layer tends to further improve. In addition, the anchoring ability between the substrate and the adhesive layer also improves, tending to obtain more stable adhesive properties.

[0079] Such isocyanate compounds are not particularly limited, but examples thereof include aromatic diisocyanates such as trimethylolpropane-modified tolylene diisocyanate, tolylene diisocyanate, 4,4-diphenylmethane diisocyanate, and xylylene diisocyanate; alicyclic diisocyanates such as isophorone diisocyanate and methylene bis(4-cyclohexyl isocyanate); and aliphatic diisocyanates such as hexamethylene diisocyanate and trimethylhexamethylene diisocyanate. The isocyanate compounds may be used alone or in combination of two or more.

[0080] Among these, trimethylolpropane-modified tolylene diisocyanate is more preferable. By using such an isocyanate compound, the cohesive strength of the adhesive layer tends to be further improved.

[0081] The content of the isocyanate compound is preferably 4.0 parts by weight or less, more preferably 0.05 to 2.0 parts by weight, and even more preferably 0.1 to 1.5 parts by weight, relative to 100 parts by weight of (meth)acrylic polymer A. When the content of the isocyanate compound is 0.1 part by weight or more, the crosslink density of the adhesive layer is further improved, cohesive failure that occurs during peeling is further suppressed, and contamination due to cohesive failure tends to be further suppressed. Furthermore, when the content of the isocyanate compound is 4.0 parts by weight or less, the crosslink density is further reduced and the elastic modulus is lowered, so the adhesive strength tends to be further improved.

[0082] 1.2.7.Other Ingredients The adhesive layer may contain additives such as a tackifier, a crosslinking retarder, an antioxidant, a metal trapping agent, an ultraviolet absorber, a plasticizer, metal powder, a filler, and a colorant, as needed.

[0083] The tackifier is not particularly limited, but examples thereof include petroleum-based resins, terpene resins, terpene-phenolic resins, aromatic modified terpene resins, coumarone-indene resins, natural resin rosin, modified rosin, glycerin ester rosin, pentaerythritol ester rosin, phenolic resins, xylene resins, alicyclic petroleum resins, styrene-based resins, and dicyclopentadiene resins.

[0084] The crosslinking retarder is not particularly limited, but examples thereof include β-diketones such as acetylacetone, hexane-2,4-dione, heptane-2,4-dione, and octane-2,4-dione; β-ketoesters such as methyl acetoacetate, ethyl acetoacetate, propyl acetoacetate, butyl acetoacetate, octyl acetoacetate, oleyl acetoacetate, lauryl acetoacetate, and stearyl acetoacetate; and benzoylacetone.

[0085] The antioxidant is not particularly limited, but examples thereof include methylhydroquinone, hydroquinone, 2,2-methylene-bis(4-methyl-6-tertiarybutylphenol), catechol, hydroquinone monomethyl ether, monotertiarybutylhydroquinone, 2,5-ditertiarybutylhydroquinone, p-benzoquinone, 2,5-diphenyl-p-benzoquinone, 2,5-ditertiarybutyl-p-benzoquinone, picric acid, citric acid, phenothiazine, tertiarybutylcatechol, 2-butyl-4-hydroxyanisole, 2,6-ditertiarybutyl-p-cresol, and 4-[[4,6-bis(octylthio)-1,3,5-triazin-2-yl]amino]-2,6-ditertiarybutylphenol.

[0086] 1.3.Protection Film The pressure-sensitive adhesive tape of the present embodiment may have a protective film attached to the pressure-sensitive adhesive layer to protect the pressure-sensitive adhesive layer. The protective film is preferably one with excellent releasability, since it is peeled off when the pressure-sensitive adhesive tape is used. The protective film is not particularly limited, but examples thereof include a film made of a fluororesin with low surface energy and a film of polyethylene terephthalate whose surface is treated with a silicone-based release agent.

[0087] 1.4.Usage The pressure-sensitive adhesive tape of this embodiment can be suitably used for processing semiconductor wafers, semiconductor devices, or various semiconductor packages. The semiconductor wafer may be a wafer before being singulated on which electronic circuits and the like have been formed. The semiconductor device refers to various semiconductor chips or elements containing such chips after singulation, and the semiconductor package refers to a semiconductor chip to which a resin for protecting the semiconductor chip and connection terminals for connecting the semiconductor chip to the outside are attached.

[0088] 2. Manufacturing method of adhesive tape The method for producing the adhesive tape is not particularly limited, but may include a method of forming an adhesive layer on a substrate.

[0089] The substrate of the pressure-sensitive adhesive tape of this embodiment can be manufactured according to well-known techniques. The means for forming the substrate is not particularly limited, but the above-mentioned various materials are mixed using a conventional melt-kneading method or various mixing devices (single-screw or twin-screw extruders, rolls, Banbury mixers, various kneaders, etc.) so that the components are uniformly dispersed, and the mixture is then formed into the substrate by the T-die method, calendar method, or inflation method. A film-forming method using a T-die method with an extruder that has good thickness accuracy is preferred.

[0090] The adhesive layer of the adhesive tape of this embodiment can be manufactured according to well-known techniques. The means for forming the adhesive layer is not particularly limited, but may include dissolving the above-mentioned materials in a solvent such as an organic solvent to form a varnish, applying this to a protective film by knife coating, roll coating, spray coating, gravure coating, bar coating, curtain coating, or the like, and then removing the solvent to form an adhesive layer. The adhesive tape is then produced by laminating this onto a substrate.

[0091] In this embodiment, an aging treatment may be performed after the adhesive layer is formed. In the aging treatment, the formed adhesive layer is stored at a predetermined temperature. The temperature condition is not particularly limited, but is preferably 30 to 50°C, and more preferably 35 to 45°C. The storage time is also not particularly limited, but is preferably 24 to 150 hours, and more preferably 48 to 100 hours. By performing this aging treatment, the adhesive strength and curing characteristics of the adhesive layer change.

[0092] 3. Processing method The processing method of this embodiment includes a lamination step of laminating the adhesive tape and an adherend, a dicing step of processing the adherend while the adhesive tape and the adherend are laminated together, and an ultraviolet irradiation step of irradiating the adhesive tape with ultraviolet light after the dicing step, thereby processing a semiconductor wafer, a semiconductor device, or various semiconductor packages as the adherend. Furthermore, the processing method of this embodiment may, if necessary, include a pick-up step of picking up individual chips from the adhesive tape after ultraviolet light irradiation.

[0093] The laminating step is not particularly limited as long as it is a step of laminating the adhesive layer of the adhesive tape to the adherend. The laminating step may be performed at room temperature and normal pressure, or may be performed under elevated temperature or reduced pressure as necessary.

[0094] The method for dividing the silicon wafer into individual pieces by the dicing process is not particularly limited, and any conventionally known method can be used. For example, a silicon wafer can be cut into semiconductor chips by rotating a dicing blade containing diamond abrasive grains at high speed using a dicing device.

[0095] The ultraviolet irradiation method is not particularly limited, and any conventionally known method can be used. For example, an ultraviolet irradiation device is used to irradiate ultraviolet rays onto the adhesive tape in the dicing step.

[0096] Thereafter, the pick-up method is not particularly limited, and a conventionally known method can be used. For example, an expanding device is used to stretch the adhesive tape after ultraviolet irradiation in the planar direction, and each chip can be separated and then picked up by a pick-up device. [Example]

[0097] The present invention will be described in more detail below using examples and comparative examples, but the present invention is not limited to these.

[0098] (Synthesis Example 1: Acrylic Polymer 1) 82 parts by weight of 2-ethylhexyl acrylate, 18 parts by weight of acrylic acid, and 0.05 parts by weight of a polymerization initiator (azobisisobutyronitrile) were copolymerized in ethyl acetate at 65° C. for 24 hours to obtain a copolymer.

[0099] Glycidyl methacrylate was reacted with the carboxyl groups of the structural units derived from acrylic acid in the copolymer obtained as described above to obtain an acrylic polymer 1 having a double bond in the side chain. In the acrylic polymer 1, of 100 mol % of the structural units derived from acrylic acid in the copolymer, 60 mol % of the structural units were structural units that had reacted with glycidyl methacrylate, and 40 mol % of the structural units were structural units derived from acrylic acid.

[0100] (Synthesis Example 2: Acrylic Polymer 2) 82 parts by weight of 2-ethylhexyl acrylate, 18 parts by weight of acrylic acid, and 0.05 parts by weight of a polymerization initiator (azobisisobutyronitrile) were copolymerized in ethyl acetate at 65° C. for 24 hours to obtain a copolymer.

[0101] Glycidyl methacrylate was reacted with the carboxyl groups of the structural units derived from acrylic acid in the copolymer obtained as described above to obtain an acrylic polymer 2 having a double bond in the side chain. In the acrylic polymer 2, of 100 mol % of the structural units derived from acrylic acid in the copolymer, 45 mol % of the structural units were structural units that had reacted with glycidyl methacrylate, and 55 mol % of the structural units were structural units derived from acrylic acid.

[0102] (Synthesis Example 3: Synthesis of Acrylic Polymer 5) 82 parts by weight of 2-ethylhexyl acrylate, 18 parts by weight of acrylic acid, and 0.05 parts by weight of a polymerization initiator (azobisisobutyronitrile) were copolymerized in ethyl acetate at 65° C. for 24 hours to obtain a copolymer.

[0103] Glycidyl methacrylate was reacted with the carboxyl groups of the structural units derived from acrylic acid in the copolymer obtained as described above to obtain an acrylic polymer 5 having a double bond in the side chain. In the acrylic polymer 5, of 100 mol % of the structural units derived from acrylic acid in the copolymer, 80 mol % of the structural units were structural units that had reacted with glycidyl methacrylate, and 20 mol % of the structural units were structural units derived from acrylic acid.

[0104] Example 1 To a solution containing 50 parts by weight of acrylic polymer 1 and 50 parts by weight of acrylic polymer 2, 0.2 parts by weight of trimethylolpropane-modified tolylene diisocyanate (Coronate L-45E, manufactured by Nippon Polyurethane Co., Ltd.), 2.1 parts by weight of photopolymerization initiator (2,2-dimethoxy-2-phenylacetophenone (Omnirad 651, manufactured by BASF)), and amine 1 (1,4-diazabicyclo[2,2,2]octane-2-methanol, RZETA, manufactured by Tosoh Corporation, approximately 33% active ingredient, diluted with dipropylene glycol) were added so that the active ingredient was 1.0 part by weight, to prepare a UV-curable resin composition.

[0105] This resin composition was applied to the release-treated surface of a polyethylene terephthalate protective film that had been previously subjected to a release treatment so that the adhesive layer would have a thickness of 10 μm after drying, and then dried at 120°C for 1 minute. The surface of the adhesive layer was then bonded to the corona-treated surface of a polyolefin film (substrate) that had previously been corona-treated on the surface to which the adhesive layer would be bonded, thereby transferring the adhesive to the substrate. This was then aged for 72 hours in an atmosphere of 40°C to obtain an adhesive tape.

[0106] Example 2 An adhesive tape was produced in the same manner as in Example 1, except that acrylic polymer 2 was not used and 100 parts by weight of acrylic polymer 1 was used.

[0107] Example 3 An adhesive tape was produced in the same manner as in Example 1, except that acrylic polymer 1 was not used and 100 parts by weight of acrylic polymer 2 was used.

[0108] Example 4 An adhesive tape was prepared in the same manner as in Example 1, except that acrylic polymer 1 was not used, and 95 parts by weight of acrylic polymer 2 and 5 parts by weight of acrylic polymer 4 (polyacrylic acid (manufactured by Fujifilm Wako Pure Chemical Industries, product name Polyacrylic acid 5000)) were used.

[0109] Example 5 An adhesive tape was produced in the same manner as in Example 1, except that the amount of Amine 1 used was 0.5 parts by weight.

[0110] Example 6 An adhesive tape was produced in the same manner as in Example 1, except that the amount of Amine 1 used was 10.0 parts by weight.

[0111] Example 7 An adhesive tape was produced in the same manner as in Example 1, except that amine 1 was replaced with 10.0 parts by weight of amine 2 (2,2,6,6-tetramethyl-4-piperidyl methacrylate, manufactured by ADEKA: LA-87).

[0112] Example 8 An adhesive tape was prepared in the same manner as in Example 1, except that amine 1 was replaced with 10.0 parts by weight of amine 3 (dioctylamine, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.).

[0113] Example 9 An adhesive tape was produced in the same manner as in Example 1, except that acrylic polymer 1 was not used, and 90 parts by weight of acrylic polymer 2 and 10 parts by weight of acrylic polymer 4 were used.

[0114] Example 10 An adhesive tape was produced in the same manner as in Example 1, except that neither acrylic polymer 1 nor acrylic polymer 2 was used, and 100 parts by weight of acrylic polymer 5 was used.

[0115] (Comparative Example 1) An adhesive tape was produced in the same manner as in Example 1, except that amine 1 was not used.

[0116] (Comparative Example 2) An adhesive tape was produced in the same manner as in Example 1, except that amine 1 was replaced with 10.0 parts by weight of amine 4 (polyoxypropylenediamine, manufactured by HUNTMAN: Jeffamine D-400), which is a primary amine.

[0117] (Comparative Example 3) An adhesive tape was prepared in the same manner as in Example 1, except that acrylic polymer 1 and acrylic polymer 2 were replaced with 100 parts by weight of acrylic polymer 3 (manufactured by Mitsubishi Chemical: Coponyl N-2993) not containing a carboxyl group and 30 parts by weight of acrylic oligomer 1 (manufactured by Negami Chemical Industries: Artresin UN-904M).

[0118] <Measurement of the acid value of the adhesive layer> The acid value [mgKOH / g] of the adhesive layer of each Example and Comparative Example was measured by the following method. Specifically, 1 g of the resin composition for forming the adhesive layer was weighed out, and this resin composition was dissolved in 30 g of tetrahydrofuran (THF) in a conical beaker. After that, 2 or 3 drops of phenolphthalein were added. Then, 0.1 N KOH solution (solvent: 2-propanol (IPA)) was added dropwise from a burette to determine the neutralization point, and the acid value was calculated.

[0119] <Measurement of glass transition temperature> The glass transition temperature of the (meth)acrylic polymer A was measured by differential scanning calorimetry (DSC) based on JIS K7121.

[0120] <Adhesive strength> The adhesive strength of the pressure-sensitive adhesive tapes of each Example and Comparative Example was measured in accordance with the 180° peel strength measurement method of JIS Z0237 (2009) (Method 1: Test method in which the tape and sheet are peeled at 180° from a stainless steel test plate). Specifically, the pressure-sensitive adhesive tape was adhered to a silicon wafer with a cleaned surface using a pressure-adhering device (roller mass 2 kg), and the 180° peel strength SO when the pressure-sensitive adhesive tape was peeled off at 180° from the silicon wafer was measured using a universal tensile tester (Tensilon model: RTG-1210, manufactured by ORIENTEC) in an environment of temperature 23°C and humidity 50%.

[0121] In addition, adhesive tape was pressed onto a silicon wafer whose surface had been cleaned using a pressure-bonding device (roller mass 2 kg), and ultraviolet light was applied to the adhesive tape at 150 mJ / cm using a high-pressure mercury lamp. 2 The adhesive tape was then peeled off from the silicon wafer at an angle of 180°, and the 180° peel strength S1 was measured in the same manner as above. The measurement conditions are as follows: (Measurement conditions) Measurement mode: Tensile Tensile speed: 300 mm / min Chuck distance: 50mm Measurement sample width: 20 mm

[0122] Under the above measurement conditions, the adhesive strength before and after ultraviolet irradiation was measured and evaluated according to the following evaluation criteria. (Evaluation criteria: adhesive strength before UV irradiation) A:8.0N / 20mm or more B: 4.0N / 20mm or more and less than 8.0N / 20mm C: Less than 4.0N / 20mm (Evaluation criteria: adhesive strength after UV irradiation) A: Less than 0.5N / 20mm B: 0.5N / 20mm or more, less than 1.0N / 20mm C:1.0N / 20mm or more

[0123] <Evaluation of adhesive strength fluctuation rate during high temperature storage> The pressure-sensitive adhesive tapes of each Example and Comparative Example were stored in a thermostatic chamber at 40°C for one month, and then stored in an atmosphere of 23°C and 50% RH for two hours or more, and after adjusting the tape temperature to 23°C, the 180° peel strength was measured by the same method as for the adhesive strength described above. The ratio of the adhesive strength of the adhesive tape after storage to the adhesive strength of the adhesive tape before storage was calculated as the rate of change in adhesive strength, and the rate of change in adhesive strength during high-temperature storage was evaluated based on the following evaluation criteria. (Evaluation criteria: Adhesion strength fluctuation rate when stored at high temperatures) A: 0.90 or more B: 0.85 or more and less than 0.90 C: Less than 0.85

[0124] <Double bond equivalent> The double bond equivalent was calculated by measuring the iodine value and determining the amount of double bonds in accordance with "Testing methods for acid value, saponification value, ester value, iodine value, hydroxyl value and unsaponifiable matter of chemical products" (JIS K 0070). Specifically, iodine monochloride solution was added to the sample to add to the double bonds, and excess I was titrated with sodium thiosulfate solution to calculate the double bond equivalent using the following formula: A={(BC)×f×1.269} / S A: Iodine value B: Amount of sodium thiosulfate solution used in the blank test (mL) C: Amount of sodium thiosulfate solution used in titration (mL) f: Factor of sodium thiosulfate solution S: mass of sample (g)

[0125] [Table 1] [Industrial Applicability]

[0126] The pressure-sensitive adhesive tape of the present invention has industrial applicability as a tape for processing semiconductor wafers, particularly as a pressure-sensitive adhesive tape used in a dicing process.

Claims

1. A substrate and an adhesive layer laminated on at least one surface of the substrate, the adhesive layer contains a (meth)acrylic polymer having a carboxyl group, an amine compound having a secondary or higher amine group, and a photopolymerization initiator; the (meth)acrylic polymer has a polymerizable double bond at a terminal and / or a side chain, the content of the amine compound is 0.5 parts by weight or more relative to 100 parts by weight of the (meth)acrylic polymer, The acid value of the adhesive layer is 10 mgKOH / g or more. Adhesive tape.

2. the content of the amine compound is 15 parts by weight or less relative to 100 parts by weight of the (meth)acrylic polymer; The adhesive tape according to claim 1 .

3. The amine compound includes a cyclic amine compound. The adhesive tape according to claim 1 .

4. The cyclic amine compound includes an alicyclic amine. The adhesive tape according to claim 3.

5. the cyclic amine compound includes 1,4-diazabicyclo[2.2.2]octane or a derivative thereof; The adhesive tape according to claim 3.

6. The acid value of the adhesive layer is 100 mgKOH / g or less. The adhesive tape according to claim 1 .

7. The (meth)acrylic polymer has a structural unit represented by the following formula (1): The adhesive tape according to claim 1 . 【Chemistry 1】 (In the formula, R 1 represents an organic group having a polymerizable double bond, and R 2 represents a single bond or an organic group having 1 to 6 carbon atoms, and R 3 represents a hydrogen atom or a methyl group.

8. the adhesive layer contains an isocyanate compound, the content of the isocyanate compound is 4.0 parts by weight or less relative to 100 parts by weight of the (meth)acrylic polymer; The adhesive tape according to claim 1 .

9. a bonding step of bonding the pressure-sensitive adhesive tape according to any one of claims 1 to 8 to an adherend; a dicing step of processing the adherend in a state where the adhesive tape and the adherend are stuck together; an ultraviolet irradiation step of irradiating the adhesive tape with ultraviolet light after the dicing step, The adherend is a semiconductor wafer, a semiconductor device, or various semiconductor packages. Processing method.

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