Adhesive tape

Abstract

The purpose of this invention is to provide an adhesive tape with excellent peel performance of wafer components and the ability to suppress paste residue on wafer components. This invention is an adhesive tape having an adhesive layer containing an ABA-type block copolymer and a crosslinking agent. The ABA-type block copolymer contains block A having a structure derived from an aromatic vinyl monomer and block B having a structure derived from a (meth)acrylic acid monomer. Block B contains a structure derived from a monomer containing a crosslinking functional group, and the tensile modulus of the adhesive layer is 0.008 MPa or more and 2 MPa or less.

Description

Technical Field

[0001] This invention relates to an adhesive tape. Prior Technology

[0002] In the manufacturing process of semiconductor devices, multiple wafer components disposed on an adhesive layer are sometimes transferred onto a driving circuit substrate. For example, a micro-LED display is a display device in which each pixel is a tiny light-emitting diode (LED) chip, and these micro-LED chips emit light to display images. Micro-LED displays offer high contrast and fast response times. Furthermore, because they do not require color filters used in liquid crystal displays (LCDs) and organic EL displays, they can be made thinner, thus attracting attention as a next-generation display device. In a micro-LED display, multiple micro-LED chips are densely packed in a planar shape.

[0003] In the manufacturing process of semiconductor components such as micro LED displays, for example, a transfer laminate on which multiple wafer components are disposed on an adhesive layer is made to face a driving circuit substrate, and the wafer components are peeled off from the transfer laminate to make an electrical connection with the driving circuit substrate (transfer step).

[0004] As a method for peeling off a self-transfer printing laminate for wafer components, a known method is to focus laser light onto the back side of the support of the self-transfer printing laminate on the adhesive layer (e.g., Patent Document 1). This method is also known as laser ablation. Furthermore, a method is also known in which thermally expandable particles or microcapsules are incorporated into the adhesive layer, and the thermally expandable particles or microcapsules are thermally expanded by thermally pressing the transfer laminate with the drive circuit board. This deformation of the adhesive layer reduces the bonding area, thereby peeling off the wafer component (e.g., Patent Documents 2 and 3). [Previous Technical Documents] [Patent Literature]

[0005] Patent Document 1: Japanese Patent Application Publication No. 2019-138949 Patent Document 2: Japanese Patent Application Publication No. 2019-15899 Patent Document 3: Japanese Patent Application Publication No. 2003-7986 Summary of the Invention

[0006] [The problem that the invention aims to solve]

[0007] However, previous methods of removing chip components have problems such as poor chip component removal, which makes it difficult to transfer chip components with good yield. Furthermore, when using conventional adhesive layers for laser ablation, there is a problem of adhesive residue adhering to the wafer components. That is, even if the wafer components can be peeled off by laser ablation, the adhesive layer may be torn during the peeling process, leaving residue. To prevent residue adhesion, one approach is to increase the cross-linking degree (gel fraction) of the adhesive layer. However, simply increasing the cross-linking degree (gel fraction) of the adhesive layer makes the wafer components more difficult to peel off, thus making it difficult to simultaneously improve both the peeling performance and the inhibition of adhesive residue on the wafer components.

[0008] The purpose of this invention is to provide an adhesive tape that has excellent peeling performance for wafer components and can suppress paste residue on wafer components. [Technical means to solve the problem]

[0009] The present invention 1 is an adhesive tape having an adhesive layer comprising an ABA-type block copolymer and a crosslinking agent. The ABA-type block copolymer comprises a block A having a structure derived from an aromatic vinyl monomer and a block B having a structure derived from a (meth)acrylic acid monomer. The block B comprises a structure derived from a monomer containing a crosslinking functional group. The tensile modulus of the adhesive layer is 0.008 MPa or more and 2 MPa or less.

[0010] The second invention is an adhesive tape as described in the first invention, wherein the tensile strength of the adhesive layer is 1 MPa or higher.

[0011] The third invention is an adhesive tape as described in the first or second invention, wherein the gel content of the adhesive layer is 70% by weight or more.

[0012] The present invention 4 is an adhesive tape as described in the present invention 1, 2 or 3, wherein the adhesive layer has a sphere-shaped phase separation structure.

[0013] The present invention 5 is an adhesive tape as described in the present invention 1, 2 or 3, wherein the adhesive layer has a cylindrical phase separation structure.

[0014] The present invention 6 is an adhesive tape as described in the present invention 1, 2, 3, 4 or 5, wherein the content of block A in the above-mentioned ABA-type block copolymer is more than 1% by weight and less than 40% by weight.

[0015] The present invention 7 is an adhesive tape as described in the present invention 1, 2, 3, 4, 5 or 6, wherein the crosslinking agent is an epoxy crosslinking agent or an isocyanate crosslinking agent.

[0016] The present invention 8 is an adhesive tape of the present invention 1, 2, 3, 4, 5, 6 or 7, wherein the above-mentioned (meth)acrylate monomer contains: an alkyl (meth)acrylate monomer having 8 or more carbon atoms, and the content of the structure derived from the above-mentioned alkyl (meth)acrylate monomer having 8 or more carbon atoms in the above-mentioned ABA-type block copolymer is 40% by weight or more.

[0017] The present invention 9 is an adhesive tape as described in the present invention 1, 2, 3, 4, 5, 6, 7 or 8, wherein, in the above-mentioned ABA-type block copolymer, the glass transition temperature of the above-mentioned block B is above -30°C and below 0°C.

[0018] The present invention 10 is an adhesive tape of the present invention 1, 2, 3, 4, 5, 6, 7, 8 or 9, wherein the weight average molecular weight of the above-mentioned ABA-type block copolymer is 100,000 or more.

[0019] The present invention 11 is an adhesive tape as described in inventions 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10, wherein the adhesive layer further contains a tackifier that is liquid at room temperature.

[0020] The present invention 12 is an adhesive tape as described in invention 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or 11, wherein the thickness of the adhesive layer is 3 μm or more and 30 μm or less. The present invention will now be described in detail.

[0021] The inventors have investigated the use of an adhesive layer containing a specific ABA-type block copolymer and a crosslinking agent in an adhesive tape having an adhesive layer, and have adjusted the tensile modulus of elasticity of the adhesive layer to a specific range. The inventors have discovered that with this type of adhesive tape, even when wafer components are peeled off by laser etching, the peeling performance of the wafer components can be improved, and paste residue on the wafer components can be suppressed, thus completing the present invention.

[0022] Here, Figure 1 shows a cross-sectional view schematically illustrating one example of a step in which a wafer component disposed on an adhesive layer is peeled off by laser etching. In the step shown in Figure 1, a wafer component 1 is disposed on an adhesive layer 4 stacked on a support 5. The wafer component 1 is peeled off by laser light 8a irradiated by a laser light irradiation device 8, and an electrical connection (transfer step) is made between the wafer component 1 and the drive circuit board 7. The adhesive layer 4 can be a double-sided adhesive tape with a substrate. Alternatively, the stacked body 9 of the support and the adhesive layer can be a single-sided adhesive tape with the support 5 as the substrate. Furthermore, in this step, if laser light 8a is irradiated onto the adhesive layer 4, the portion of the adhesive layer 4 irradiated with laser light 8a will deform. More specifically, if laser light 8a is irradiated onto the adhesive layer 4, the molecules of the adhesive layer 4 will be broken down by heat, resulting in low molecular weight, instantaneous evaporation, or sublimation due to high temperature. Therefore, the portion of the adhesive layer 4 irradiated with laser light 8a will deform. This allows the chip component 1 to be peeled off. By using laser light 8a, the peeling of the chip component 1 can be initiated within a very small area. Therefore, even when extremely small chip components such as micro LED chips are arranged, the chip component 1 can be peeled off individually with high peeling performance.

[0023] The adhesive tape of the present invention is an adhesive tape having an adhesive layer. The aforementioned adhesive layer contains an ABA-type block copolymer and a crosslinking agent. The ABA-type block copolymer contains block A, which has a structure derived from an aromatic vinyl monomer, and block B, which has a structure derived from a (meth)acrylic acid monomer. Furthermore, here (meth)acrylic acid refers to acrylic acid or methacrylic acid. By including the ABA-type block copolymer and the crosslinking agent in the adhesive layer, the tensile modulus of elasticity, tensile strength, gel fraction, etc. of the adhesive layer can be easily adjusted to the range described later, so that the adhesive tape of the present invention has excellent peeling performance of wafer parts and can suppress paste residue on wafer parts.

[0024] The aforementioned ABA-type block copolymer is a copolymer containing block A (hereinafter also referred to as "hard segment") with a rigid structure and block B (hereinafter also referred to as "soft segment") with a flexible structure. The two blocks of the aforementioned ABA-type block copolymer are not easily compatible. This ABA-type block copolymer exhibits a heterogeneous phase separation structure where spherical islands formed by the aggregation of block A are dispersed within a sea of ​​blocks B, or a heterogeneous phase separation structure where cylindrical structures formed by the aggregation of block A are dispersed within a sea of ​​blocks B. This phase separation structure with dispersed spherical islands is also referred to as a spherical phase separation structure, and the phase separation structure with dispersed cylindrical structures is also referred to as a cylindrical phase separation structure. Furthermore, by making these phase separation structures simulate crosslinking points, the aforementioned ABA-type block copolymer can be endowed with rubber elasticity, thus easily adjusting the tensile modulus of elasticity, tensile strength, gel fraction, etc., of the aforementioned adhesive layer to the ranges described later. The ABA-type block copolymers mentioned above are preferably ABA-type triblock copolymers.

[0025] Block A is not particularly limited, as long as it has a rigid structure. In addition to the structure derived from aromatic vinyl monomers, it can also have a structure derived from compounds with cyclic structures or compounds with shorter side-chain substituents. Block B can also have a structure derived from monomers other than the (meth)acrylic acid monomers, without losing the effects of the present invention.

[0026] In block A above, the aromatic vinyl monomers may include, for example, styrene, α-methylstyrene, p-methylstyrene, chlorostyrene, etc. These aromatic vinyl monomers may be used alone or in combination of two or more. Among them, styrene is preferred in terms of further improving the peeling performance of the wafer parts of the adhesive tape and further suppressing the residue of paste on the wafer parts. Furthermore, in this specification, the structure derived from the aromatic vinyl monomer refers to the structure shown in the following general formula (1) or (2).

[0027]

[0028] In general formulas (1) and (2), R1 represents a substituent having an aromatic ring. Examples of substituents R1 having an aromatic ring include phenyl, tolyl, and chlorophenyl.

[0029] In the aforementioned ABA-type block copolymer, the content of the structure derived from the aromatic vinyl monomer is not particularly limited, but is preferably between 1% and 30% by weight. By ensuring that the content of the structure derived from the aromatic vinyl monomer is within the aforementioned range, the tensile modulus of elasticity and the tensile strength of the adhesive layer can be adjusted to a more favorable range. The more favorable lower limit of the content of the structure derived from the aromatic vinyl monomer is 5% by weight, further preferably 8% by weight, particularly preferably 10% by weight, more preferably 28% by weight, further preferably 25% by weight, and particularly preferably 20% by weight.

[0030] In block B above, the (meth)acrylic acid monomer can be a single monomer or multiple monomers. Furthermore, in this specification, the structure derived from the (meth)acrylic acid monomer refers to the structure shown in the following general formula (5) or (6).

[0031]

[0032] In general formulas (5) and (6), R3 represents a side chain. Examples of side chains R3 include: methyl, ethyl, propyl, butyl, isobutyl, pentyl, hexyl, cyclohexyl, heptyl, octyl, isooctyl, 2-ethylhexyl, nonyl, isononyl, decyl, lauryl, stearyl, isostearyl, isocamphenyl, etc.

[0033] Examples of the aforementioned (meth)acrylate monomers include: methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, isobutyl methacrylate, pentyl methacrylate, hexyl methacrylate, cyclohexyl methacrylate, heptyl methacrylate, octyl methacrylate, isooctyl methacrylate, 2-ethylhexyl methacrylate, nonyl methacrylate, isononyl methacrylate, decyl methacrylate, lauryl methacrylate, stearyl methacrylate, isostearyl methacrylate, and isocamphenyl methacrylate. These (meth)acrylate monomers can be used alone or in combination of two or more. From the perspective of balancing the peeling performance of wafer components with the effect of inhibiting paste residue on wafer components, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and lauryl (meth)acrylate are preferred, and butyl acrylate, 2-ethylhexyl acrylate, and lauryl acrylate are even more preferred. Furthermore, in this specification, (meth)acrylate refers to acrylate or methacrylate.

[0034] In the aforementioned ABA-type block copolymer, the content of the structure derived from the (meth)acrylic acid monomer is not particularly limited, as long as the effects of the present invention can be achieved. Preferably, it is 30% by weight or more and 99% by weight or less. More preferably, the content of the structure derived from the (meth)acrylic acid monomer is 40% by weight or more and 95% by weight or less, and even more preferably 50% by weight or more and 90% by weight or less.

[0035] Preferably, the above-mentioned (meth)acrylic acid monomers are (meth)acrylic acid ester monomers containing: alkyl groups having 8 or more carbon atoms. By including the aforementioned (meth)acrylate monomers containing alkyl groups having 8 or more carbon atoms, the tensile modulus of elasticity of the adhesive layer can be adjusted to a better range. Examples of the aforementioned alkyl groups having 8 or more carbon atoms include: octyl methacrylate, 2-ethylhexyl methacrylate, isononyl methacrylate, decyl methacrylate, lauryl methacrylate, and isostearyl methacrylate. 2-ethylhexyl methacrylate and lauryl methacrylate are particularly preferred.

[0036] In the aforementioned ABA-type block copolymer, the content of the structure derived from the alkyl (meth)acrylate monomer having 8 or more carbon atoms is not particularly limited, and can be 0% by weight, with a preferred lower limit of 35% by weight. If the content of the structure derived from the alkyl (meth)acrylate monomer having 8 or more carbon atoms is 35% by weight or more, the peeling performance of the adhesive tape wafer parts can be further improved. A more preferred lower limit of the content of the structure derived from the alkyl (meth)acrylate monomer having 8 or more carbon atoms is 40% by weight. There is no particular limit to the content of the (meth)acrylate monomers derived from the above-mentioned structures having alkyl groups with 8 or more carbon atoms. However, based on the viewpoint of suppressing paste residue on wafer components, the preferred upper limit is 70% by weight, and the more preferred upper limit is 60% by weight.

[0037] In the aforementioned ABA-type block copolymer, the glass transfer temperature of block B is not particularly limited, but is preferably between -30°C and 0°C. By setting the glass transfer temperature of block B within the aforementioned range, even when transferring wafer parts with protrusions or small-sized wafer parts, the peel performance of the adhesive tape on the wafer parts can be further improved, and paste residue on the wafer parts can be further suppressed. The more preferred lower limit of the glass transfer temperature of block B is -28°C, further preferably -25°C, more preferably -5°C, and further preferably -10°C. Furthermore, the glass transition temperature of block B can be determined, for example, by using a differential scanning calorimeter (manufactured by TA Instruments, Hitachi High-Tech Science, etc.). More specifically, the value obtained during the second run of a measurement of ABA-type block copolymers using a differential scanning calorimeter (e.g., Hitachi High-Tech Science SII Exstar 6000 / DSC 6220) under nitrogen atmosphere and a heating rate of 10°C / min can be used. Furthermore, by obtaining peaks originating from block A and block B, and taking the peak from the lower temperature side as the peak originating from block B, the glass transition temperature of block B can be determined.

[0038] There is no particular limitation on the method of adjusting the glass transition temperature of the above block B to the above range. However, it is preferable to adjust the glass transition temperature of the above block B to the above range by making the above (meth)acrylic monomer contain a (meth)acrylic ester monomer that has a glass transition temperature of 0°C or higher when it becomes a homopolymer. By including the aforementioned (meth)acrylate monomers containing (meth)acrylate monomers that have a glass transition temperature of 0°C or higher when forming homopolymers, the tensile modulus of elasticity of the adhesive layer can be adjusted to a better range. Examples of (meth)acrylate monomers with a glass transition temperature of 0°C or higher when forming homopolymers include: methyl acrylate, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, tributyl acrylate, tributyl methacrylate, cyclohexyl acrylate, cyclohexyl methacrylate, isoborneol acrylate, isoborneol methacrylate, and benzyl methacrylate. Methyl acrylate and methyl methacrylate are particularly preferred.

[0039] In the aforementioned ABA-type block copolymer, the content of the structure derived from the (meth)acrylate monomer with a glass transition temperature of 0°C or higher when forming a homopolymer is not particularly limited, and can be 0% by weight, with a preferred lower limit of 35% by weight. If the content of the structure derived from the (meth)acrylate monomer with a glass transition temperature of 0°C or higher when forming a homopolymer is 35% by weight or more, the peel performance of the wafer parts of the adhesive tape can be further improved. A more preferred lower limit of the content of the structure derived from the (meth)acrylate monomer with a glass transition temperature of 0°C or higher when forming a homopolymer is 40% by weight. There is no particular limit to the content of (meth)acrylate monomers derived from the structure that have a glass transition temperature of 0°C or higher when they become homopolymers. However, from the perspective of temporarily fixing wafer components, the preferred upper limit is 60% by weight, and the more preferred upper limit is 50% by weight.

[0040] Block B contains a structure derived from a monomer containing a cross-linking functional group. By incorporating the aforementioned block B with the structure derived from a monomer containing a crosslinking functional group, the cohesive force of the adhesive layer is enhanced by the crosslinking of the crosslinking functional group, thereby improving the peel performance of the wafer component of the adhesive tape and suppressing paste residue on the wafer component. The aforementioned crosslinking functional group may or may not be crosslinked, but is preferably crosslinked. However, even if the structure remains uncrosslinked, the cohesive force of the adhesive layer will be enhanced by the interaction between the functional groups, thereby improving the peel performance of the wafer component of the adhesive tape and suppressing paste residue on the wafer component. Furthermore, in this specification, the structure derived from a monomer having a crosslinking functional group refers to the structure shown in the following general formula (3) or (4).

[0041]

[0042] In general formulas (3) and (4), R2 represents a substituent containing at least one crosslinking functional group. Examples of crosslinking functional groups include: carboxyl, hydroxyl, epoxy, double bond, triple bond, amino, amide, nitrile, etc. Furthermore, the substituent R2 containing at least one crosslinking functional group may also contain alkyl, ether, carbonyl, ester, carbonate, amide, urethane, etc. as its constituent elements.

[0043] The monomers with cross-linking functional groups mentioned above are not particularly limited, and examples include: monomers containing carboxyl groups, monomers containing hydroxyl groups, monomers containing epoxy groups, monomers containing double bonds, monomers containing triple bonds, monomers containing amino groups, monomers containing amide groups, and monomers containing nitrile groups. These monomers with cross-linking functional groups can be used alone or in combination of two or more. In terms of further improving the peel performance of the wafer parts of the adhesive tape and further suppressing the residue of paste on the wafer parts, it is preferable to select at least one from the group consisting of monomers containing carboxyl groups, monomers containing hydroxyl groups, monomers containing epoxy groups, monomers containing double bonds, monomers containing triple bonds, and monomers containing amide groups. Examples of the aforementioned carboxyl-containing monomers include (meth)acrylic acid and other (meth)acrylic acid monomers. Examples of the aforementioned hydroxyl-containing monomers include hydroxyalkyl acrylates or hydroxyalkyl methacrylates such as 4-hydroxybutyl (meth)acrylic acid and 2-hydroxyethyl (meth)acrylic acid. Examples of the aforementioned epoxy-containing monomers include glycidyl (meth)acrylic acid. Examples of the aforementioned double-bond-containing monomers include allyl (meth)acrylic acid and hexanediol di(meth)acrylic acid. Examples of the aforementioned triple-bond-containing monomers include propargyl (meth)acrylic acid. Examples of the aforementioned acetylammonium-containing monomers include methacrylamide. Among these, in terms of further improving the peel performance of the wafer components of the adhesive tape and further suppressing paste residue on the wafer components, carboxyl-containing monomers and hydroxyl-containing monomers are preferred. Furthermore, (meth)acrylic acid monomers and hydroxyalkyl acrylates are more preferred, and acrylic acid, 2-hydroxyethyl acrylate, and 4-hydroxybutyl acrylate are even more preferred.

[0044] Furthermore, in addition to block B, block A may also contain the structure derived from a monomer containing a cross-linking functional group.

[0045] In the aforementioned ABA-type block copolymer, the content of the monomer structure derived from the crosslinking functional group (the sum of the content in block A and the content in block B) is not particularly limited, but is preferably 0.1% by weight to 30% by weight. By ensuring that the content of the monomer structure derived from the crosslinking functional group is within the aforementioned range, the cohesive force of the adhesive layer can be further improved, the peeling performance of the adhesive tape on the wafer parts can be further improved, and paste residue on the wafer parts can be further suppressed. The lower limit of the content of the monomer structure derived from the crosslinking functional group is more preferably 0.5% by weight, and more preferably 1% by weight, more preferably 25% by weight, and more preferably 20% by weight.

[0046] In the aforementioned ABA-type block copolymer, the content of block A (hard segment) is not particularly limited, but is preferably 1% to 40% by weight. By setting the content of block A within the aforementioned range, the tensile modulus of elasticity of the adhesive layer can be adjusted to a more favorable range. The more favorable lower limit of the content of block A is 2% by weight, further preferably 5% by weight, and even more preferably 10% by weight. The more favorable upper limit of the content of block A is 35% by weight, further preferably 30% by weight, further preferably 25% by weight, further preferably 22% by weight, and even more preferably 20% by weight.

[0047] The weight-average molecular weight (Mw) of the aforementioned ABA-type block copolymer is not particularly limited, but is preferably between 50,000 and 800,000. By setting the weight-average molecular weight within the aforementioned range, the tensile modulus of elasticity of the adhesive layer can be adjusted to a more favorable range. The more favorable lower limit of the aforementioned weight-average molecular weight is 75,000, further preferably 100,000, and further preferably 200,000. The more favorable upper limit of the aforementioned weight-average molecular weight is 600,000. Furthermore, the weight-average molecular weight can be determined, for example, using GPC (Gel Permeation Chromatography) and conversion to standard polystyrene. More specifically, for example, a Water 2690 Separations Module can be used as the measuring instrument, a Showa Denko G.K.K.K.K.K.K.L.G ...

[0048] To obtain the aforementioned ABA-type block copolymer, the monomers of block A and block B are subjected to free radical reactions in the presence of a polymerization initiator to obtain block A and block B, respectively, followed by reaction or copolymerization. Alternatively, after obtaining block A, the monomers of block B can be added to continue copolymerization. The above-mentioned free radical reaction method, namely polymerization method, can be used as an example, such as solution polymerization (boiling point polymerization or isothermal polymerization), emulsion polymerization, suspension polymerization, bulk polymerization, etc.

[0049] The crosslinking agent is not particularly limited and can be selected according to the type of crosslinking functional group in the ABA-type block copolymer. Examples include isocyanate-based crosslinking agents, epoxy-based crosslinking agents, aziridine-based crosslinking agents, and metal chelate-based crosslinking agents. More specifically, for example, when the crosslinking functional group in the ABA-type block copolymer is a carboxyl group, examples of crosslinking agents include epoxy-based crosslinking agents, isocyanate-based crosslinking agents, and metal chelate-based crosslinking agents. In terms of making it easier to adjust the tensile modulus of the adhesive layer to a better range, epoxy-based crosslinking agents and isocyanate-based crosslinking agents are preferred.

[0050] The content of the crosslinking agent is not particularly limited. The degree of crosslinking (gel fraction) of the adhesive layer can be adjusted by adjusting the amount of crosslinking functional groups in the ABA-type block copolymer and the content of the crosslinking agent. The content of the crosslinking agent is preferably 0.01 parts by weight to 10 parts by weight relative to 100 parts by weight of the ABA-type block copolymer. By setting the content of the crosslinking agent within the above range, the ABA-type block copolymer can be moderately crosslinked, thereby improving the cohesive force of the adhesive layer, further improving the peel performance of the adhesive tape on the wafer components, and further suppressing paste residue on the wafer components. The lower limit of the content of the crosslinking agent is more preferably 0.1 parts by weight, the upper limit is more preferably 5 parts by weight, the lower limit is more preferably 0.15 parts by weight, and the upper limit is more preferably 3 parts by weight.

[0051] The aforementioned adhesive layer may further contain tackifiers (adhesion-improving agents). The aforementioned tackifier is not particularly limited; although it can be a solid tackifier at room temperature, it is preferred to be a liquid tackifier at room temperature. By including the aforementioned liquid tackifier in the adhesive layer, the tensile modulus of elasticity of the adhesive layer can be easily adjusted to a better range, thereby further improving the peel performance of the adhesive tape on the wafer components. Furthermore, room temperature refers to 20°C to 25°C, and liquid refers to having fluidity.

[0052] The above-mentioned tackifiers that are solid at room temperature are not particularly limited, and examples include: rosin ester resins, terpene phenol resins, terpene resins, benzofuran resins, etc. The above-mentioned thickeners that are liquid at room temperature are not particularly limited; for example, liquid rosin esters and liquid terpene phenols can be listed.

[0053] The content of the aforementioned tackifier, which is solid at room temperature, is not particularly limited. However, considering the peel performance of the adhesive tape to wafer components, it is preferable that the adhesive layer does not contain the tackifier. When the aforementioned tackifier, which is solid at room temperature, is present, it is preferably 10 parts by weight or less relative to 100 parts by weight of the aforementioned ABA-type block copolymer. By keeping the content of the aforementioned tackifier, which is solid at room temperature, within the aforementioned range, the peel performance of the adhesive tape to wafer components can be further improved. A more preferable upper limit for the content of the aforementioned tackifier, which is solid at room temperature, is 5 parts by weight. Furthermore, the content of the aforementioned tackifier, which is liquid at room temperature, is not particularly limited, but is preferably 5 to 50 parts by weight relative to 100 parts by weight of the aforementioned ABA-type block copolymer. By ensuring that the content of the aforementioned tackifier, which is liquid at room temperature, is within the aforementioned range, the peel performance of the adhesive tape on the wafer components can be further improved. The preferred lower limit of the content of the aforementioned tackifier, which is liquid at room temperature, is 10 parts by weight, and the preferred upper limit is 30 parts by weight.

[0054] The adhesive layer described above preferably contains an ultraviolet absorber. By including the ultraviolet absorber in the adhesive layer, the laser light stimulation is efficiently converted into heat or vibration in the adhesive layer, thus making it easier for the adhesive layer to deform due to laser ablation, and further improving the peeling performance of the wafer components of the adhesive tape.

[0055] The above-mentioned ultraviolet absorbers are not particularly limited; for example, benzotriazole ultraviolet absorbers and hydroxyphenyltriazole ultraviolet absorbers can be listed. These are ultraviolet absorbers, etc. Examples include: ethylhexyl methoxycinnamate, octyl methoxycinnamate, ethylhexyl p-methoxycinnamate, diethylaminohydroxybenzoyl benzoate, and bis(ethylhexyl)-hydroxyphenol-methoxyphenyl trimethylolpropionate. The following are examples of materials: tert-butylmethoxydiphenylmethane, etc. Among these, considering their excellent compatibility with other components in the aforementioned adhesive layer, benzotriazole-based UV absorbers and hydroxyphenyltriazole are preferred. These are ultraviolet absorbers. These ultraviolet absorbers can be used alone or in combination of two or more.

[0056] The content of the aforementioned ultraviolet absorber is not particularly limited, but a preferred lower limit relative to 100 parts by weight of the aforementioned ABA-type block copolymer is 6 parts by weight. If the content of the aforementioned ultraviolet absorber is 6 parts by weight or more, the peeling performance of the wafer parts of the adhesive tape can be further improved. A more preferred lower limit of the content of the aforementioned ultraviolet absorber is 10 parts by weight, and a more preferred lower limit is 15 parts by weight. There is no particular upper limit to the content of the aforementioned ultraviolet absorber, but from the perspective of ensuring the adhesion of the aforementioned adhesive layer, the preferred upper limit is 30 parts by weight.

[0057] The aforementioned adhesive layer may further contain inorganic fillers such as fumed silica. By incorporating the aforementioned inorganic fillers, the cohesive force of the adhesive layer can be improved, thereby further enhancing the peeling performance of the adhesive tape on the wafer components and further suppressing paste residue on the wafer components.

[0058] The aforementioned adhesive layer may further contain known additives such as plasticizers, resins, surfactants, waxes, and microparticle fillers. These additives may be used alone or in combination of two or more.

[0059] The lower limit of the tensile modulus of the adhesive layer is 0.008 MPa, and the upper limit is 2 MPa. If the tensile modulus is 0.008 MPa or higher, the adhesive layer is less likely to tear during laser ablation of the wafer component, thus suppressing paste residue on the wafer component. If the tensile modulus is 2 MPa or lower, deformation of the adhesive layer caused by laser ablation is more likely to occur, improving the peeling performance of the adhesive tape on the wafer component. The preferred lower limit of the tensile modulus is 0.01 MPa, the preferred upper limit is 0.7 MPa, the more preferred lower limit is 0.015 MPa, the more preferred upper limit is 0.68 MPa, and even more preferably the upper limit is 0.65 MPa.

[0060] Furthermore, considering that even when transferring wafer parts with protrusions or small-sized wafer parts, the peeling performance of the adhesive tape to the wafer parts can be further improved, and the residue of paste on the wafer parts can be further suppressed, the preferred lower limit of the tensile modulus is 0.01 MPa, and the preferred upper limit is 2 MPa. Based on the same consideration, the preferred lower limit of the tensile modulus is 0.7 MPa, the preferred upper limit is 1.9 MPa, the preferred lower limit is 0.8 MPa, the preferred upper limit is 1.8 MPa, and the preferred upper limit is 1.5 MPa. Furthermore, the tensile modulus of elasticity of the adhesive layer can be calculated, for example, using an automatic stereographic analyzer (manufactured by Shimadzu Corporation) according to JIS K7161:2014, by measuring the slope of the stress-strain curve when the adhesive layer is stretched at a tensile speed of 500 mm / min under conditions of 23°C and 50% relative humidity, with a strain of 100%. Alternatively, when the adhesive tape has a substrate, the tensile modulus of elasticity can be measured after removing the substrate to create a sample containing only the adhesive layer. As for methods of removing the substrate, to avoid altering the adhesive layer, treatments involving solvents, chemical reactions, or high temperatures should be avoided; there are no particular limitations. Specific methods include: bonding the adhesive layers together and then peeling them off at an appropriate temperature and peeling speed to remove the substrate; or physically grinding the substrate.

[0061] The tensile strength of the adhesive layer is not particularly limited, but a preferred lower limit is 1 MPa. If the tensile strength is 1 MPa or higher, the adhesive layer is less likely to tear when the wafer is peeled off by laser etching, which can further suppress paste residue on the wafer. A more preferred lower limit of the tensile strength is 1.3 MPa, and a more preferred lower limit is 1.4 MPa. There is no particular limit to the upper limit of the fracture strength. If the fracture strength is too high, the tensile modulus of elasticity will also increase, and the peeling performance of the wafer parts of the adhesive tape will decrease. Therefore, the preferred upper limit is 10 MPa, the more preferred upper limit is 8 MPa, the more preferred upper limit is 4 MPa, and the more preferred upper limit is 3.1 MPa. Furthermore, the tensile strength of the adhesive layer can be calculated, for example, using an automatic stereoscopic plotter (manufactured by Shimadzu Corporation), according to JIS K7161:2014, by measuring the stress at fracture when the adhesive layer is stretched at a tensile speed of 500 mm / min in an environment with a temperature of 23°C and a relative humidity of 50%. Alternatively, when the adhesive tape has a substrate, the tensile strength can be measured after removing the substrate to create a sample containing only the adhesive layer. As for methods of removing the substrate, to avoid altering the adhesive layer, treatments involving solvents, chemical reactions, or high temperatures should be avoided; there are no particular limitations. Specific methods include: bonding the adhesive layers together and then peeling them off at an appropriate temperature and peeling speed to remove the substrate; or physically grinding the substrate.

[0062] The gel content of the adhesive layer is not particularly limited, but a preferred lower limit is 70% by weight. If the gel content is 70% by weight or more, the peeling performance of the adhesive tape on the wafer components can be further improved, and paste residue on the wafer components can be further suppressed. A more preferred lower limit of the gel content is 80% by weight. There is no particular upper limit to the gel fraction mentioned above. Based on the viewpoint that it is easy to adjust the tensile modulus of the adhesive layer to a better range, the preferred upper limit is 98% by weight, and the more preferred upper limit is 95% by weight. Furthermore, the gel fraction of the adhesive layer can be determined by the following methods. Only 0.1 g of the adhesive layer (adhesive composition) of the self-adhesive tape was removed and immersed in 50 mL of ethyl acetate. The mixture was shaken for 24 hours at 23°C and 200 rpm. After shaking, the ethyl acetate was separated from the swollen adhesive composition by absorbing ethyl acetate using a metal sieve (200 mesh). The separated adhesive composition was dried at 110°C for 1 hour. The weight of the dried adhesive composition including the metal sieve was measured, and the gel fraction of the adhesive layer was calculated using the following formula. Gel fraction (weight %) = 100 × (W1 - W2) / W0 (W0: Initial weight of adhesive composition, W1: Weight of adhesive composition including metal screen after drying, W2: Initial weight of metal screen)

[0063] There are no particular limitations on the method of adjusting the tensile modulus of elasticity, tensile strength, gel fraction, etc. of the above adhesive layer to the above range. For example, methods such as adjusting the composition or weight average molecular weight (Mw) of the above ABA block copolymer, the type or amount of the above crosslinking agent can be listed as described above.

[0064] The phase separation structure of the adhesive layer is not particularly limited, but it is preferably spherical. By giving the adhesive layer a spherical phase separation structure, the tensile modulus of elasticity, tensile strength, gel fraction, etc., of the adhesive layer can be easily adjusted to the range described later, which can further improve the peel performance of the adhesive tape on the wafer parts and further suppress paste residue on the wafer parts. The phase separation structure of the adhesive layer can be controlled by adjusting the ratio of each block in the ABA-type block copolymer.

[0065] The adhesive layer described above can also have a cylindrical phase-separated structure. By giving the adhesive layer a cylindrical phase-separated structure, the tensile modulus of elasticity, tensile strength, gel fraction, etc., of the adhesive layer can be easily adjusted to the range described later, which can further improve the peel performance of the adhesive tape on the wafer parts and further suppress paste residue on the wafer parts. In particular, when the adhesive layer has a cylindrical phase-separated structure, the tensile modulus of elasticity, tensile strength, etc., of the adhesive layer can be easily adjusted to a relatively large range, which can further improve the peel performance of the adhesive tape on the wafer parts even when transferring wafer parts with protrusions or small-sized wafer parts, and further suppress paste residue on the wafer parts. Furthermore, the phase separation structure of the adhesive layer can be confirmed by observation using a transmission electron microscope (TEM). Spherical refers to a spherical structure of microphase separation, while cylindrical refers to a cylindrical structure of microphase separation.

[0066] When the adhesive layer has a spherical phase separation structure, the size of the island structures within the spherical phase separation structure is not particularly limited. The preferred lower limit for the average major diameter of the island structures is 5 nm, the preferred upper limit is 100 nm, the more preferred lower limit is 10 nm, and the more preferred upper limit is 50 nm. By ensuring that the average major diameter is within the aforementioned range, the peeling performance of the adhesive tape on the wafer components can be further improved, and paste residue on the wafer components can be further suppressed. Furthermore, the average major diameter of the island structures in a spherical phase-separated structure can be determined by the following method. The adhesive layer was observed using a transmission electron microscope (TEM) at 5000x magnification, acquiring an image of a 4.3 μm × 4.3 μm region. The acquired image was then automatically binarized using image analysis software (e.g., Avizo, ver 2019.4, manufactured by Thermo Fisher Scientific). The major axis of each island structure (dark area) was measured based on the binarized image, and the arithmetic mean of these measurements was taken as the average major axis. Furthermore, the details of the automatic binarization method are based on known literature ("Automatic Threshold Selection Method Based on Discriminant and Least Squares Criterion", Nobuyuki Otsu, Journal of Electronics and Information Communications D, Vol. J63-D, No. 4, pp. 349-356).

[0067] The thickness of the adhesive layer is not particularly limited, but a preferred lower limit is 3 μm and a preferred upper limit is 200 μm. If the thickness of the adhesive layer is 3 μm or more, the retention and release performance of the adhesive tape on the wafer components can be further improved. If the thickness of the adhesive layer is 200 μm or less, paste residue on the wafer components can be further suppressed. Regarding further improving the retention and release performance of the adhesive tape on the wafer components and further suppressing paste residue on the wafer components, a more preferred lower limit of the thickness of the adhesive layer is 5 μm, and a more preferred upper limit is 50 μm. Based on the same consideration, a further preferred lower limit of the thickness of the adhesive layer is 10 μm, a further preferred upper limit is 30 μm, a further preferred lower limit is 15 μm, and a further preferred lower limit is 20 μm.

[0068] The adhesive tape of the present invention can be a supported type with a substrate or a non-supported type without a substrate. In the case of a supported type, the adhesive tape of the present invention can be a single-sided adhesive tape with an adhesive layer on only one side of the substrate, or a double-sided adhesive tape with adhesive layers on both sides of the substrate. In the case of a double-sided adhesive tape, it is sufficient that at least one side has an adhesive layer as described above. The adhesive layers on both sides can have the same composition or different compositions.

[0069] The aforementioned substrate is not particularly limited. Examples of materials that can be used as substrates include: polyethylene terephthalate (PET), polyethylene naphthalate (PET), polyacetal, polyamide, polycarbonate, polyphenylene ether, polybutylene terephthalate (PET), ultra-high molecular weight polyethylene (UHMWPE), polystyrene, polyarylate, polyurethane, polyetherurethane, polyphenylene sulfide, polyetheretherketone, polyimide, polyetherimide, fluoropolymers, and liquid crystal polymers. Among these, PET and PET are preferred for their superior heat resistance.

[0070] The thickness of the aforementioned substrate is not particularly limited, but the preferred lower limit is 5 μm and the preferred upper limit is 188 μm. By making the thickness of the aforementioned substrate within the above range, an adhesive tape with moderate plasticity and excellent workability can be produced. The preferred lower limit of the thickness of the aforementioned substrate is 12 μm, and the preferred upper limit is 125 μm.

[0071] The application of the adhesive tape of the present invention is not particularly limited. Because the adhesive tape of the present invention has excellent peeling performance of wafer components and can suppress paste residue on wafer components, it is suitable for use in the step of peeling wafer components disposed on adhesive layer by laser etching as shown in FIG1. The aforementioned chip components are not particularly limited; for example, Mini LED chips, micro LED chips, and optical chips for image sensors can be listed, with micro LED chips being particularly preferred.

[0072] The method for transferring wafer components using the adhesive tape of the present invention is not particularly limited. For example, the following wafer component transfer method can be cited, which includes: a step of placing the wafer component on the adhesive layer of the adhesive tape of the present invention, and a step of irradiating the wafer component with laser light to peel it off. Furthermore, the manufacturing method of electronic components using the adhesive tape of the present invention is also not particularly limited. For example, manufacturing methods of electronic components including the wafer component transfer method described above can be cited. According to these methods, wafer components can be transferred with better yield, and paste residue on the wafer components can be suppressed. [Effects of the Invention]

[0073] According to the present invention, an adhesive tape with excellent peeling performance of wafer components and the ability to suppress paste residue on wafer components can be provided. Simple Explanation of the Diagram

[0074] [Figure 1] is a cross-sectional view schematically illustrating one example of the steps of removing a wafer component disposed on an adhesive layer by laser ablation. Implementation

[0075] The present invention will be described in more detail below by way of examples, but the present invention is not limited to these examples.

[0076] (Example 1) (1) Preparation of ABA-type block copolymers 0.902 g of 1,6-hexanedithiol, 1.83 g of carbon disulfide, and 11 mL of dimethylformamide were added to a two-necked flask and stirred at 25°C. Triethylamine (2.49 g) was added dropwise over 15 minutes, and the mixture was stirred at 25°C for 3 hours. Then, methyl-α-bromophenylacetic acid (2.75 g) was added dropwise over 15 minutes, and the mixture was stirred at 25°C for 4 hours. Subsequently, 100 mL of extraction solvent (n-hexane:ethyl acetate = 50:50) and 50 mL of water were added to the reaction mixture for separation extraction. The organic layers obtained from the first and second separation extractions were mixed and washed sequentially with 50 mL of 1 M hydrochloric acid, 50 mL of water, and 50 mL of saturated brine. Sodium sulfate was added to the washed organic layer and the mixture was dried. The sodium sulfate was then filtered, and the filtrate was concentrated using an evaporator to remove the organic solvent. The obtained concentrate was purified by silicone column chromatography to obtain the RAFT agent.

[0077] 15 parts by weight of styrene (St), 2 parts by weight of acrylic acid (AAc), 1.9 parts by weight of RAFT agent, and 0.2 parts by weight of 2,2'-azobis(2-methylbutyronitrile) (ABN-E) were added to a two-necked flask. The flask was purged with nitrogen gas, and the temperature was raised to 85°C. Subsequently, the mixture was stirred at 85°C for 6 hours to carry out the polymerization reaction (first stage reaction). After the reaction was completed, 4000 parts by weight of n-hexane were added to the flask and stirred to precipitate the reactants. Then, the unreacted monomers and RAFT agent were filtered, and the reactants were dried under reduced pressure at 70°C to obtain the copolymer (block A).

[0078] A mixture containing 81 parts by weight of butyl acrylate (BA), 2 parts by weight of acrylic acid (AAc), 0.058 parts by weight of ABN-E, and 50 parts by weight of ethyl acetate, along with the copolymer (block A) obtained above, was added to a two-necked flask. The flask was purged with nitrogen while the temperature was raised to 85°C. Subsequently, the mixture was stirred at 85°C for 6 hours to carry out the polymerization reaction (second-stage reaction), thereby obtaining a reaction solution containing the block copolymer formed by block A and block B. A portion of the reaction solution was taken, and 4000 parts by weight of n-hexane were added and stirred to precipitate the reactants. The unreacted monomers and solvents were then filtered, and the reactants were dried under reduced pressure at 70°C to obtain ABA-type block copolymers. The weight-average molecular weight of the obtained ABA-type block copolymer was determined by GPC, and the result was 250,000. Furthermore, the assay was performed using a Water 2690 Separations Module, a Showa Denko G.K.K.K.K.K.K.L. GPC column, and ethyl acetate as the solvent, at a sample flow rate of 1 mL / min and a column temperature of 40°C.

[0079] Furthermore, for the obtained ABA-type block copolymer, the glass transition temperature of block B was determined using the values ​​obtained in the second run of a differential scanning calorimeter (Hitachi High-Tech Science, SII Exstar 6000 / DSC 6220) under nitrogen atmosphere and a heating rate of 10°C / min. Additionally, the peaks originating from block A and block B were obtained, and the peak from the lower temperature side was taken as the peak originating from block B to determine the glass transition temperature of block B.

[0080] (2) Manufacturing of adhesive tape The obtained ABA-type block copolymer was dissolved in ethyl acetate with a solid content of 35%. One part by weight of Tetrad C (manufactured by Mitsubishi Gas Chemical Co., Ltd.) was added as an epoxy crosslinking agent, and eight parts by weight of Tinuvin 928 (manufactured by BASF Japan Co., Ltd.) were added as an ultraviolet absorber, relative to 100 parts by weight of the ABA-type block copolymer. The mixture was then thoroughly stirred to obtain an adhesive solution. Using a dressing applicator, the obtained adhesive solution was applied to a corona-treated PET film with a thickness of 50 μm, with the dried film thickness being 20 μm. The film was then dried at 110°C for 3 minutes. Subsequently, it was cured at 40°C for 48 hours to obtain the adhesive tape.

[0081] (3) Determination of the tensile modulus of elasticity of the adhesive layer For the adhesive layer of the adhesive tape, the tensile modulus of elasticity was calculated by using an automatic stereoscopic plotter (manufactured by Shimadzu Corporation) according to JIS K7161:2014, based on the slope of the stress-strain curve when the strain was 100% under a tensile speed of 500 mm / min in an environment with a temperature of 23°C and a relative humidity of 50%.

[0082] (4) Determination of the tensile strength of the adhesive layer For the adhesive layer of the adhesive tape, the fracture strength was calculated by using an automatic stereoscopic plotter (manufactured by Shimadzu Corporation) according to JIS K7161:2014, based on the stress at fracture when stretched at a tensile speed of 500 mm / min in an environment with a temperature of 23°C and a relative humidity of 50%.

[0083] (5) Determination of gel fraction of adhesive layer Only 0.1 g of the adhesive layer (adhesive composition) of the self-adhesive tape was removed and immersed in 50 mL of ethyl acetate. The mixture was shaken for 24 hours at 23°C and 200 rpm. After shaking, the ethyl acetate was separated from the swollen adhesive composition by absorbing ethyl acetate using a metal sieve (200 mesh). The separated adhesive composition was dried at 110°C for 1 hour. The weight of the dried adhesive composition including the metal sieve was measured, and the gel fraction of the adhesive layer was calculated using the following formula. Gel fraction (weight %) = 100 × (W1 - W2) / W0 (W0: Initial weight of adhesive composition, W1: Weight of adhesive composition including metal screen after drying, W2: Initial weight of metal screen)

[0084] (6) Confirmation of the phase separation structure of the adhesive layer The adhesive layer was prepared using the same method as in the examples and comparative examples. The adhesive layer was trimmed to obtain small pieces, which were then stained with a 2% osmium tetroxide aqueous solution at 60°C for 12 hours, followed by washing. Using a cryostat (LEICA, ULTRACUT FC7), the pieces were cut along the thickness direction of the adhesive layer at a temperature of -100°C to obtain sections less than 100 nm thick. The cut sections were placed on a sheet-like sieve covered with a support film to prepare the measurement samples. The obtained test samples were observed using a transmission electron microscope (JEOL Corporation, JEM-2100) at a magnification of 5000x to confirm the phase separation structure, which was found to be a spherical phase separation structure.

[0085] (Examples 2-17) The composition of the ABA-type block copolymer, the type or amount of tackifier, and the type or amount of crosslinking agent were changed as shown in Tables 1-2. Otherwise, the adhesive tape was obtained in the same manner as in Example 1. As tackifiers, ME-GH (manufactured by Arakawa Chemical Co., Ltd.) was used as a liquid (liquid at room temperature) tackifier, YS POLYSTER G-150 (manufactured by Yasuhara Chemical Co., Ltd.) was used as a non-liquid (solid at room temperature) tackifier A, and PENSEL D-135 (manufactured by Arakawa Chemical Co., Ltd.) was used as a non-liquid (solid at room temperature) tackifier B. Furthermore, in Examples 5-7, ABA-type block copolymers with a larger weight average molecular weight were prepared by extending the polymerization reaction time.

[0086] Furthermore, the letter symbols in the table are abbreviations for the following components. Styrene AAc: Acrylic acid BA: Butyl acrylate 2-EHA: 2-Ethylhexyl acrylate LA: Lauryl acrylate MA: Methyl acrylate 2-HEA: 2-Hydroxyethyl Acrylate

[0087] (Comparative Example 1) The adhesive tape was obtained in the same manner as in Example 1, except that a (meth)acrylic polymer prepared as described below was used instead of the ABA-type block copolymer.

[0088] (Preparation of (meth)acrylic acid polymers) 52 parts by weight of ethyl acetate were added to a reactor equipped with a thermometer, stirrer, and condenser. Nitrogen purging was performed, followed by heating and reflux. After boiling the ethyl acetate for 30 minutes, 0.08 parts by weight of azobisisobutyronitrile (AIB) was added as a polymerization initiator. Over a period of 1 hour and 30 minutes, 98 parts by weight of butyl acrylate (BA) and 2 parts by weight of acrylic acid (AAc) were added dropwise uniformly and slowly. Thirty minutes after the addition was complete, 0.1 parts by weight of AIB was added, and the polymerization reaction continued for 5 hours. Ethyl acetate was added to the reactor for dilution, and the reactor was cooled simultaneously to obtain a solution of (meth)acrylic acid polymer.

[0089] (Compare Examples 2-3 and 5-6) The composition of the ABA-type block copolymer was changed as shown in Table 2, except that the adhesive tape was obtained in the same manner as in Example 1.

[0090] (Comparative Example 4) The adhesive tape was obtained in the same manner as in Example 1, except that the styrene-ethylene-butene-styrene (SEBS) block copolymer (Dynaron 8300, manufactured by JSR) shown in Table 2 was used instead of the ABA-type block copolymer.

[0091] <Evaluation> The adhesive tapes obtained in the examples and comparative examples were evaluated as follows. The results are shown in Tables 1-2.

[0092] (1) Measurement of 180° adhesion The surface of a 2 mm thick SUS plate is cleaned with ethanol and then thoroughly dried. An adhesive tape, pre-cut to a width of 25 mm and a length of 10 cm, is overlapped with the SUS plate, and a 2 kg roller is rolled back and forth once to obtain a sample for testing. For the obtained test samples, the following peel test was performed: using an automatic stereoscopic plotter (manufactured by Shimadzu Corporation), according to JIS Z0237:2009, the adhesive tape was peeled off at a tensile speed of 300 mm / min in the 180° direction at an environment of 23°C and 50% relative humidity, and the 180° adhesion force (N / 25 mm) was measured.

[0093] (2) Evaluation of laser ablation (2-1) Peeling performance of wafer components (wafer size is 500 μm × 500 μm square) The obtained adhesive tape was attached to the Si wafer side of a wafer on which 10 Si wafers (500 μm × 500 μm square, 50 μm thick) were arranged. Subsequently, the Si wafers were positioned onto the adhesive tape by wafer peeling. Using a semiconductor solid-state laser, 365 nm laser light at 4 W and 4 kHz was irradiated from the substrate side of the adhesive tape onto each Si wafer, thereby peeling the Si wafers off the adhesive tape. The peeling performance of the wafer components is evaluated by marking the case where all 10 Si wafers can be peeled off as "◎", the case where 8 to 9 wafers can be peeled off as "○", and the case where fewer than 7 Si wafers can be peeled off as "×".

[0094] (2-2) Paste residue (crystal size 500 μm × 500 μm square) After evaluating the peeling performance of the wafer components, the surface of the Si wafer after peeling off the self-adhesive tape was observed under a microscope to confirm whether there was any paste residue. The case where there was no paste residue at all was marked as "◎", the case where less than 20% of the surface area of ​​the wafer component had paste residue was marked as "○", and the case where more than 20% of the surface area of ​​the wafer component had paste residue was marked as "×". The paste residue was evaluated.

[0095] (2-3) Peeling performance of small-sized wafer components (wafer size is 30 μm × 40 μm square) The peeling performance of small-sized wafer components was evaluated using the adhesive tapes obtained in Examples 12-17. The obtained adhesive tape was attached to the Si wafer side of a wafer on which 10 Si wafers (30 μm × 40 μm square, 10 μm thick) were arranged. Subsequently, the Si wafers were positioned onto the adhesive tape by wafer peeling. Using a semiconductor solid-state laser, 365 nm laser light at 4 W and 4 kHz was irradiated from the substrate side of the adhesive tape onto each Si wafer, thereby peeling the Si wafers off the adhesive tape. The peeling performance of wafer components (small wafers) is evaluated by marking the case where all 10 Si wafers can be peeled off as "◎", the case where 8 to 9 wafers can be peeled off as "○", and the case where fewer than 7 Si wafers can be peeled off as "×".

[0096] (2-4) Paste residue (crystal size 30 μm × 40 μm square) After evaluating the peeling performance of small-sized wafer components, the surface of the Si wafer after self-adhesive tape peeling was observed under a microscope to confirm the presence of any adhesive residue. A case with no adhesive residue was marked "◎", a case with adhesive residue covering less than 20% of the wafer component's surface area was marked "○", and a case with adhesive residue covering more than 20% of the wafer component's surface area was marked "×". The adhesive residue was then evaluated.

[0097] [Table 1] Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Example 9 Example 10 Example 11 Adhesive layer [parts by weight] ABA-type block copolymers [parts by weight] Segment A (Hard link segment) St 15 15 15 15 15 15 15 15 15 15 15 AAc 2 2 2 2 2 2 2 2 2 2 2 Segment B (Soft link segment) BA 81 81 41 20 81 81 20 20 41 41 20 2-FOUR - - 40 61 - - 61 61 - - 61 DAY - - - - - - - - 40 40 - MA - - - - - - - - - - - Ac 2 2 2 2 2 2 2 - 2 - 2 2-WHERE - - - - - - - 2 - 2 - Ethylene-butene - - - - - - - - - - - Liquid thickener - - - - - 20 - - - - - Non-liquid thickener A - - - - - - - - - - 20 Non-liquid thickener B - - - - - - - - - - - Crosslinking agent 1 1.25 1 1 1.25 0.5 1 3 1 1 1 UV absorber 8 8 8 8 8 8 8 8 8 8 8 Types of crosslinking agents Epoxy (Tetrad C) Epoxy (Tetrad C) Epoxy (Tetrad C) Epoxy (Tetrad C) Epoxy (Tetrad C) Epoxy (Tetrad C) Epoxy (Tetrad C) Isocyanate series (Coronate L) Epoxy (Tetrad C) Isocyanate series (Coronate L) Epoxy (Tetrad C) Mw[ten thousand] of ABA-type block copolymers 25 25 twenty two 31 54 54 45 29 34 33 31 Glass transition temperature of segment B [°C] -52 -52 -60 -64 -52 -52 -64 -65 -40 -40 -64 Tensile modulus of elasticity [MPa] 0.40 0.45 0.24 0.18 0.37 0.19 0.17 0.12 0.03 0.01 0.58 Fracture strength [MPa] 2.0 1.9 1.5 1.4 3.1 1.1 1.8 1.0 1.1 1.4 1.4 Gel fraction [weight %] 90 92 89 88 92 72 88 80 66 72 82 Phase separation structure spherical spherical spherical spherical spherical spherical spherical spherical spherical spherical spherical evaluate 180° adhesion [N / 25 mm] 2.5 1.6 2.7 2.8 4.3 1.7 4.5 3.2 2.3 0.75 4.5 500 μm × 500 μm square Peeling performance ○ ○ ○ ◎ ○ ◎ ◎ ◎ ◎ ◎ ◎ Paste residue ◎ ◎ ◎ ◎ ◎ ○ ◎ ○ ○ ◎ ◎

[0098] [Table 2] Example 12 Example 13 Example 14 Example 15 Example 16 Example 17 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 Adhesive layer [parts by weight] ABA-type block copolymers [Parts by weight] Segment A (Hard link segment) St 15 twenty one 15 15 31 31 - 15 48 9 15 38 AAc 2 2 2 2 2 2 - 2 2 - 2 2 Segment B (Soft link segment) BA 20 75 41 41 65 65 98 83 48 - - 58 2-EHA 61 - - - - - - - - - 41 - LA - - - - - - - - - - 40 - MA - - 40 40 - - - - - - - - AAc 2 2 2 2 2 2 2 - 2 - 2 2 2-HEA - - - - - - - - - - - - Ethylene-butene - - - - - - - - - 91 - - Liquid thickener - - - - - - - - - - - - Non-liquid thickener A - - - - - - - - - - - - Non-liquid thickener B 20 - - - - - - - - - - - Crosslinking agent 1 1.25 0.25 1 0.25 0.5 20 20 20 - 1 1 UV absorber 8 8 8 8 8 8 8 8 8 8 8 8 Types of crosslinking agents Epoxy (Tetrad C) Epoxy (Tetrad C) Epoxy (Tetrad C) Epoxy (Tetrad C) Epoxy (Tetrad C) Epoxy (Tetrad C) Epoxy (Tetrad C) Epoxy (Tetrad C) Epoxy (Tetrad C) - Epoxy (Tetrad C) Epoxy (Tetrad C) Mw[ten thousand] of ABA-type block copolymers 31 15 25 25 10 10 80 25 25 twenty three twenty two 25 Glass transition temperature of segment B [°C] -64 -52 -25 -25 -52 -52 -53 -55 -51 -50 -49 -52 Tensile modulus of elasticity [MPa] 0.33 0.69 0.86 1.8 1.0 1.9 0.12 0.14 4.22 0.68 0.006 2.5 Fracture strength [MPa] 1.5 4.35 10.86 11.12 14.19 10.83 0.5 2.5 4.5 3.5 0.8 18.22 Gel fraction [weight %] 86 91 88 92 42 88 88 52 88 0 89 82 Phase separation structure spherical spherical spherical spherical cylindrical cylindrical spherical spherical Layered spherical spherical Layered evaluate 180° adhesion [N / 25 mm] 4.2 2.9 0.60 0.30 0.32 0.22 3.7 11.2 1.5 6.1 1.2 0.15 500 μm × 500 μm square Peeling performance ◎ ○ ○ ○ ○ ○ ○ × × × ○ × Paste residue ◎ ◎ ◎ ◎ ◎ ◎ × × ○ ○ × ○ 30 μm × 40 μm square Peeling performance ○ ○ ◎ ◎ ◎ ◎ - - - - - - Paste residue ◎ ◎ ◎ ◎ ◎ ◎ - - - - - - [Industrial Applicability]

[0099] According to the present invention, an adhesive tape with excellent peeling performance of wafer components and the ability to suppress paste residue on wafer components can be provided.

[0100] 1: Chip components 1a: Electrode 4: Adhesive layer 5: Support body 7: Drive circuit board 7a: Electrode 8: Laser Irradiation Device 8a: Laser light 9: Laminated body of support and adhesive layer

Claims

1. An adhesive tape having an adhesive layer, characterized in that: the adhesive layer contains an ABA-type block copolymer and a crosslinking agent, the ABA-type block copolymer containing: block A having a structure derived from an aromatic vinyl monomer and block B having a structure derived from a (meth)acrylic acid monomer, block B containing: a structure derived from a monomer containing a crosslinking functional group, the content of the crosslinking agent being 3 parts by weight or less relative to 100 parts by weight of the ABA-type block copolymer, and the tensile modulus of the adhesive layer being 0.008 MPa or more and 2 MPa or less.

2. As in request item 1, the adhesive tape, wherein, The tensile strength of the adhesive layer is above 1 MPa.

3. As in request item 1 or 2, the adhesive tape, wherein, The gel content of the above adhesive layer is 70% by weight or more.

4. As in request item 1 or 2, the adhesive tape, where, The adhesive layer described above has a spherical phase separation structure.

5. As in request item 1 or 2, the adhesive tape, where, The adhesive layer described above has a cylindrical phase-separated structure.

6. As in request item 1 or 2, the adhesive tape, wherein, In the above-mentioned ABA-type block copolymer, the content of block A is more than 1% by weight and less than 40% by weight.

7. As in request item 1 or 2, the adhesive tape, wherein, The aforementioned crosslinking agent is an epoxy-based crosslinking agent or an isocyanate-based crosslinking agent.

8. As in request item 1 or 2, the adhesive tape, wherein, The above-mentioned (meth)acrylic monomers contain: (meth)acrylate monomers having an alkyl group having 8 or more carbon atoms, and the content of the structure derived from the above-mentioned (meth)acrylate monomer having an alkyl group having 8 or more carbon atoms in the above-mentioned ABA-type block copolymer is 40% by weight or more.

9. As in request item 1 or 2, the adhesive tape, wherein, In the above-mentioned ABA-type block copolymer, the glass transition temperature of block B is above -30°C and below 0°C.

10. As in request item 1 or 2, the adhesive tape, wherein, The weight-average molecular weight of the above-mentioned ABA-type block copolymers is over 100,000.

11. As in request item 1 or 2, the adhesive tape, wherein, The aforementioned adhesive layer further contains a tackifier that is liquid at room temperature.

12. As in request item 1 or 2, the adhesive tape, wherein, The thickness of the adhesive layer is between 3 μm and 30 μm.

13. As in request item 1 or 2, the adhesive tape, wherein, In the above-mentioned ABA-type block copolymer, the glass transition temperature of block B is above -60°C and below 0°C.

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