TW202132502A - Tape for semiconductor processing - Google Patents

Abstract

Provided is a tape for semiconductor processing which sufficiently reduces the influence of surface irregularities and has a moderate pressure-sensitive adhesive force and antistatic performance and which is less apt to leave an adhesive residue upon removal and can be produced through a few steps. The tape for semiconductor processing comprises: a sheet-shaped substrate comprising a substrate main body and an antistatic layer disposed on at least one surface thereof; and a pressure-sensitive adhesive layer. The antistatic layer includes a polypyrrole compound. The pressure-sensitive adhesive layer is a cured object obtained from a pressure-sensitive adhesive composition and has a thickness of 50-500 [mu]m. The pressure-sensitive adhesive composition comprises one or more polyurethanes (A), a (meth)acrylate monomer (B) comprising a compound having a (meth)acryloyloxy group, a chain-transfer agent (C), and a photopolymerization initiator (D). The polyurethanes (A) include a polyurethane (a1) having (meth)acryloyl groups at a plurality of ends.

Description

Tape for semiconductor processing

The present invention relates to tapes for semiconductor processing.

Accompanying the demand for thinning of semiconductor devices, the backside polishing step of semiconductor wafers is performed in the manufacturing steps of semiconductor devices. In the back grinding step of the semiconductor wafer, the surface of the semiconductor wafer is protected with a back grinding tape, and the back surface is ground to thin the semiconductor wafer.

In the past, various proposals have been made as back-grinding tapes used to protect the surface of semiconductor wafers. In recent years, as a backside polishing tape, even if a semiconductor wafer with bumps (electrodes) formed by soldering or the like formed on the surface is equivalent to a semiconductor wafer with irregularities on the surface, it is sought to have sufficient irregularities absorbency.

In addition, in the past, when the backside polishing tape was peeled from the semiconductor wafer, static electricity called peeling charge was generated, which destroyed the circuit of the semiconductor wafer, or foreign matter adhered to the semiconductor wafer. Therefore, to grind the tape on the back, it is required to have sufficient antistatic properties.

The treatment to prevent peeling and electrification is considered to be effective when implemented on the adhesive side. However, when the adhesive itself is added with antistatic materials such as surfactants, conductive fillers, and carbon black, the physical properties of the adhesive will change. In addition, it is difficult to adjust or suppress the adhesive properties or their changes over time. Furthermore, when the adhesive tape is peeled off, the adhesive or the added antistatic material itself may transfer to the object to be adhered, which may contaminate the object. In this case, visible paste residue, microscopic level particle adhesion, or optically unobservable liquid adhesion may occur on the surface of the object to be adhered, which may cause poor adhesion of parts in the subsequent steps. The possibility of adverse effects.

Against this background, for example, Patent Document 1 discloses an adhesive film for semiconductor wafer processing. As a back polishing tape with both uneven absorption and antistatic properties, it has a substrate layer and an uneven absorption in sequence. Resin layer, antistatic layer, and adhesive resin layer. [Prior Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Application Publication No. 2018-6540

[The problem to be solved by the invention]

However, since the adhesive film for semiconductor wafer processing described in Patent Document 1 needs to be manufactured by laminating each layer separately, the manufacturing procedure is complicated. In addition, in the back polishing tape, it is required to have an adhesive force capable of fixing an object such as a semiconductor wafer to the back polishing tape with sufficient strength. However, after attaching the back grinding tape with high adhesion to the body, process the body, and then peel off the back grinding tape, the adhesive layer of the back grinding tape will be transferred to the body and the paste remains. Condition.

The present invention was completed in view of the above-mentioned matters to provide a device with sufficient bump absorption, moderate adhesion, and antistatic performance, and it is difficult to produce paste residue after peeling off the tape for semiconductor processing, and it can be manufactured in fewer manufacturing steps. The semiconductor processing tape is used as the purpose. [Means to solve the problem]

The present invention includes the following aspects. [1] An adhesive tape for semiconductor processing, comprising: a sheet-like substrate having a substrate body and an antistatic layer provided on at least one side of the substrate body, and an adhesive layer formed on the antistatic layer The semiconductor processing tape is characterized in that the antistatic layer contains a polypyrrole compound, the adhesive layer is a cured product of an adhesive composition, the thickness of the adhesive layer is 50 to 500 μm, and the adhesive composition contains polypyrrole. Urethane (A), and (meth)acrylate monomer (B), and chain transfer agent (C), and photopolymerization initiator (D), the aforementioned polyurethane (A) It contains polyurethane (a1), and the aforementioned polyurethane (a1) has: a skeleton containing a structure derived from polyoxyalkylene polyol and a structure derived from polyisocyanate, and in plural The terminal has a (meth)acrylic acid group, and the (meth)acrylate monomer (B) contains a monofunctional (meth)acrylate and a polyfunctional (meth)acrylate. [2] The tape for semiconductor processing as described in [1], wherein the adhesive layer has a single-layer structure. [3] The tape for semiconductor processing as described in [1] or [2], wherein the chain transfer agent (C) is a polyfunctional thiol. [4] The tape for semiconductor processing as described in any one of [1] to [3], wherein the gel fraction of the adhesive layer is 50 to 65% by mass. [5] The tape for semiconductor processing as described in any one of [1] to [4], wherein the surface resistivity of the adhesive layer is less than 1×10 ¹² Ω/□. [6] The tape for semiconductor processing as described in any one of [1] to [5], wherein the (meth)acrylate monomer (B) contains the monofunctional (meth)acrylate 85~ 99 mol%, the aforementioned polyfunctional (meth)acrylate 1-15 mol%. [7] The tape for semiconductor processing as described in any one of [1] to [6], wherein the adhesive composition includes: 20-50% by mass of the polyurethane (A), and The (meth)acrylate monomer (B) is 35 to 79% by mass, the chain transfer agent (C) is 0.5 to 8% by mass, and the photopolymerization initiator (D) is 0.01 to 5% by mass. [8] The tape for semiconductor processing as described in any one of [1] to [7], wherein the adhesive composition system further contains fatty acid ester (E). [Effects of the invention]

According to the present invention, it is possible to provide a tape for semiconductor processing that has sufficient unevenness absorption, moderate adhesion, and antistatic performance, and is difficult to produce paste residue after peeling off the tape for semiconductor processing.

Moreover, since the adhesive layer of the semiconductor processing tape of the present invention is a hardened material of the adhesive composition, it has sufficient concavity and convexity absorbency and adhesive force, and a layer having concavity and convexity absorption and a layer having adhesive force can be separately provided. Manufacturing with fewer manufacturing steps. Furthermore, by forming the adhesive layer on the base material with the antistatic layer, sufficient antistatic performance can be achieved. Accordingly, the tape for semiconductor processing of the present invention is suitable as a back polishing tape for surface protection when performing a back polishing step of a semiconductor wafer with bumps formed on the surface equal to an object having uneven portions on the surface.

Hereinafter, the embodiments of the present invention will be described in detail. However, the present invention is not limited to the embodiments shown below.

＜Tape for semiconductor processing＞ The tape for semiconductor processing in this embodiment has a sheet-like base material and an adhesive layer formed on the single side of the base material. The substrate has a substrate body and an antistatic layer provided on at least one side of the substrate body. The aforementioned antistatic layer contains a polypyrrole compound. The aforementioned adhesive layer is a cured product of the adhesive composition described later. The thickness of the aforementioned adhesive layer is 50 to 500 μm. The aforementioned adhesive composition includes polyurethane (A), (meth)acrylate monomer (B), chain transfer agent (C), and photopolymerization initiator (D). The aforementioned polyurethane (A) contains polyurethane (a1). The aforementioned polyurethane (a1) has a skeleton including a polyoxyalkylene polyol-derived structure and a polyisocyanate-derived structure, and has a (meth)acryloyl group at a plurality of ends. The aforementioned (meth)acrylate monomer (B) contains monofunctional (meth)acrylate and polyfunctional (meth)acrylate. Still, the so-called "tape" here is not limited to tape-shaped ones, but also includes rectangular or round sheets.

(Substrate body) The material of the base body can be appropriately selected, and examples thereof include resin materials. Examples of resin materials include polyolefins such as polyethylene (PE) and polypropylene (PP); polyethylene terephthalate (PET), polybutylene terephthalate (PBT), and polyethylene naphthalate Polyester sheets such as ethylene glycol; polyvinyl chloride (PVC); polyimide (PI); polyphenylene sulfide (PPS); ethylene vinyl acetate (EVA); polytetrafluoroethylene (PTFE), etc. Among these resin materials, since a sheet with moderate flexibility is obtained, it is preferable to use PE, PP, and PET. The resin material may be used alone or in combination of two or more kinds.

When a resin sheet made of a resin material is used as the base body, the resin sheet may be a single layer or a multilayer structure with two or more layers (for example, a three-layer structure). In the resin sheet having a multilayer structure, the resin material constituting each layer may be a resin material that contains only one type alone, or may contain two or more types of resin materials.

Furthermore, on the surface forming the antistatic layer of the base body, if necessary, easy bonding treatments such as acid treatment, alkali treatment, primer treatment, corona treatment, plasma treatment, ultraviolet treatment, ozone treatment, etc. can be performed.

The thickness of the base body can be appropriately selected according to the material of the base body, etc. The tape for semiconductor processing may be used for the purpose of attaching a semiconductor wafer with uneven portions on the surface and then peeling it off. In addition, when the tape for semiconductor processing uses a resin sheet as the base body, the thickness of the base body is preferably, for example, 10~1000μm, more preferably 50~300μm. When the thickness of the base body is 10 μm or more, the rigidity of the tape for semiconductor processing is improved. Therefore, when the tape for semiconductor processing is attached to or peeled off the semiconductor wafer to be adhered, the tape for semiconductor processing tends to be less likely to wrinkle and float. In addition, when the thickness of the base body is 1000 μm or less, the semiconductor processing tape attached to the semiconductor wafer is easily peeled from the semiconductor wafer, and the workability (handleability, handling) becomes better.

(Antistatic layer) At least one side of the base body has an antistatic layer. The aforementioned antistatic layer contains a polypyrrole compound. The polypyrrole compound is not particularly limited if it is a polymer of pyrrole and/or a pyrrole derivative, and a small amount of monomers other than pyrrole and pyrrole derivative may be contained as a polymerization component. Examples of pyrrole derivatives include N-alkylpyrrole, 3-alkylpyrrole, 3,4-dialkylpyrrole, 3-alkoxypyrrole, 3,4-dialkoxypyrrole, 3-chloropyrrole, 3,4-Dichloropyrrole and so on. By having an antistatic layer containing a polypyrrole compound, the antistatic effect of the semiconductor processing tape becomes stable over time and non-polluting.

The means for providing the antistatic layer is not particularly limited, and various well-known methods can be used. For example, the following methods (i) to (vi) can be cited. (i) A method of dissolving pyrrole and/or pyrrole derivatives in organic solvents such as diethyl ether, methanol, tetrahydrofuran (THF), and coating the base material, and then drying and removing the organic solvent (e.g., Japanese Patent Application Publication No. 3- 122115); (ii) After applying pyrrole and/or pyrrole derivatives to the substrate body, immersing in a salt or acid organic solvent, water or a mixture thereof and doping, drying to remove the solvent method (e.g., Japanese Patent Application Publication Bulletin 4-285626); (iii) According to the chemical oxidation polymerization method, the pyrrole monomer is polymerized in the presence of a chemical oxidation polymerization catalyst and a dopant in the treatment solution put into the substrate body, and the surface of the substrate body is polymerized. The method of pyrrole coating (for example, Japanese Patent Laid-Open No. 2000-280335); (iv) A method of coating an aqueous solution containing fine particles coated on the surface of pyrrole and/or pyrrole derivatives on the surface of the substrate body, and then stretching after drying (for example, Japanese Patent Application Laid-Open No. 8-58044); (v) A method of laminating a layer containing polypyrrole and/or polypyrrole derivatives, organic electron acceptor, and thermoplastic resin on the surface of the substrate body (for example, Japanese Patent Application Laid-Open No. 10-278188); (vi) The fine particles of polypyrrole and/or polypyrrole derivatives are dispersed in a hydrophilic solvent using a polymer dispersant and/or dopant, and then mixed with a hydrophilic binder resin to prepare a resin composition; the resin A method in which the composition is coated on a substrate body such as a polymer film and then dried to remove the solvent (for example, Japanese Patent Application Publication No. 2001-334598).

Among them, from the standpoint of adhesion to the base body and adhesion to the adhesive layer, it is preferable to use "(vi) polypyrrole and/or polypyrrole derivative fine particles using a polymer dispersant and/ Or dopant, dispersed in a hydrophilic solvent, and then mixed with a water-soluble or water-dispersible binder resin to prepare a resin composition; after the resin composition is coated on the base body, the solvent is dried and the solvent is removed. method". For example, well-known coating methods such as bar coaters, air knife coaters, blade coaters, rod coaters, gravure coaters, size press coaters, horizontal roll coaters, etc. can be used.

The film thickness of the antistatic layer is preferably 0.1 to 20 μm, more preferably 0.5 to 10 μm. If the thickness of the antistatic layer is within this range, it will give full play to the antistatic performance. The content of the polypyrrole compound in the antistatic layer is preferably 5 to 80% by mass, more preferably 10 to 70% by mass. If it is 5 mass% or more, sufficient antistatic performance is obtained, and if it is 80 mass% or less, economic efficiency is also good.

As the polymer dispersant, specifically, polymer acids, salts of these polymer acids, and ester products of these polymer acids, etc. can be cited. These may be used alone or in combination of two types. Used above. Specific examples of polymer acids include polymer acids such as polystyrene sulfonic acid, polyacrylic acid, polyallyl sulfonic acid, and alginic acid. Specific examples of the salt of the polymer acid include neutralizing salts such as sodium salt, potassium salt, and ammonium salt. The dopant is not particularly limited, and it is preferable to use molecular iodine and/or iodide ion. When iodide ions are used, the iodide ion value is not specifically specified. By using iodine and/or iodide ions, the conductivity and adhesion to the substrate body are further improved.

Examples of water-soluble or water-dispersible binder resins include polyester, polyurethane, acrylic resin, vinyl resin, epoxy resin, and amide resin. These individual skeleton structures can substantially have a composite structure by copolymerization or the like. Examples of binder resins having a composite structure include acrylic resin grafted polyester, acrylic resin grafted polyurethane, vinyl resin grafted polyester, vinyl resin grafted polyurethane, etc. . By containing these resins, the strength of the antistatic layer or the adhesion to the substrate body can be improved. The water-soluble or water-dispersible binder resin may be used singly, or two or more of them may be used in combination.

In addition, the resin composition may contain a crosslinking reactive compound if necessary. Cross-linking reactive compounds can improve the cohesion, surface hardness, scratch resistance, solvent resistance, and water resistance of the coating layer mainly through cross-linking reaction with functional groups contained in other resins or compounds, or self-crosslinking. . As the crosslinking reactive compound that can be used, melamine-based, benzoguanamine-based, urea-based amino resins, or oxazoline-based, epoxy-based, and glyoxal-based resins are suitably used. Other polymer backbones also include polymer-type cross-linking reactive compounds with reactive groups.

The resin composition can contain additives such as surfactants, defoamers, coating modifiers, tackifiers, organic lubricants, organic particles, inorganic particles, antioxidants, ultraviolet absorbers, dyes, and pigments. Although these additives can be used alone, if necessary, two or more of them can be used in combination.

(Adhesive layer) The adhesive layer is formed on the antistatic layer of the substrate. When the antistatic layer is formed on both sides of the substrate body, an adhesive layer is formed on either side of the antistatic layer.

The adhesive layer is a cured product of the adhesive composition described later. The adhesive layer is, in particular, a photocured material of the adhesive composition described later. The tape for semiconductor processing may be attached to a substrate such as a semiconductor wafer with irregularities on the surface, and then used for peeling purposes. In this case, the adhesive layer has the function of protecting the surface of the object in the back grinding step by fixing the tape for semiconductor processing with sufficient adhesive force to the surface of the object. In addition, the adhesive layer becomes smooth by absorbing the unevenness of the surface of the adherend, and has the function of improving the accuracy of the back grinding step. Furthermore, the adhesive layer reduces the peeling charge that occurs when the tape for semiconductor processing is peeled from the adherend. In addition, the adhesive layer included in the tape for semiconductor processing of the present embodiment does not generate a paste residue when the tape for semiconductor processing is peeled off.

The thickness of the adhesive layer of this embodiment is 50 to 500 μm, preferably 60 to 400 μm, and more preferably 70 to 300 μm. When the thickness of the adhesive layer is 50 μm or more, the uneven absorbency and adhesive force of the tape for semiconductor processing become better. In addition, when the thickness of the adhesive layer is 500 μm or less, the control of the thickness of the adhesive layer becomes easier.

When the tape for semiconductor processing of the present embodiment is attached to an object having uneven portions on the surface, the thickness of the adhesive layer greatly depends on the height of the uneven portion on the surface of the object. The thickness of the adhesive layer is preferably set to be greater than the height of the uneven portion of the surface so as to obtain sufficient absorbency of unevenness. Accordingly, for example, when the unevenness on the surface is a bump formed by a semiconductor wafer, it is preferable to set the thickness of the adhesive layer to be more than twice the height dimension of the bump. The height of the bump is usually 30~200μm. For example, when the height of the bump is 100μm, it is better to set the thickness of the adhesive layer to 200μm or more. When the height of the bump is 200μm, it is better to The thickness of the adhesive layer is set to be 400 μm or more.

The adhesive layer may have a single-layer structure, or may have a multilayer structure in which the adhesive layer of this embodiment and one or more other adhesive layers different from the adhesive layer of this embodiment are laminated. As other adhesive layers, conventionally known adhesive layers can be used. In this embodiment, when the adhesive layer has a multilayer structure, the adhesive layer of this embodiment needs to be present on the outermost surface. In addition, in the semiconductor processing tape of this embodiment, a layer other than the adhesive layer may be present between the adhesive layer and the base material within a range that does not hinder the hardening of the adhesive layer. From the viewpoint of shortening the step, the adhesive layer preferably has a single-layer structure.

The gel fraction of the adhesive layer is preferably 50 to 65% by mass. When the gel fraction is 50% by mass or more, the occurrence of paste residue caused by peeling off the semiconductor processing tape attached to the adherend can be more effectively suppressed. In addition, when the gel fraction is 65% by mass or less, the adhesive layer has sufficient fluidity, so that the uneven absorbency of the tape for semiconductor processing becomes more favorable. The gel fraction of the adhesive layer is more preferably 52% by mass or more. In addition, the gel fraction of the adhesive layer is more preferably 63% by mass or less. The preferable range of the gel fraction of the adhesive layer can be achieved, for example, by adjusting the composition of the adhesive composition described later in the preferable range.

(Measurement of the gel fraction of the adhesive layer) The gel fraction of the adhesive layer was measured by the following method. First, a sheet is cut out of the tape for semiconductor processing in a size of about 1 g, the adhesive layer is peeled from the base material, and the mass is measured as a sample for measurement. Next, the sample for measurement was immersed in 50 ml of toluene, and left to stand at room temperature for 72 hours. Then, the measurement sample was taken out from the toluene, dried at 80°C for 5 hours, and the mass was measured again. Furthermore, the gel fraction was calculated according to the following formula. Gel fraction (%)=[A/B]×100 A: The mass of the measurement sample after immersing in toluene (the mass of toluene is not included) B: The mass of the measurement sample before immersion in toluene

The surface resistivity of the adhesive layer is preferably less than 1×10 ¹² Ω/□, and more preferably less than 1×10 ¹¹ Ω/□. When the surface resistivity is less than 1×10 ¹² Ω/□, the peeling charge when peeling off the tape for semiconductor processing attached to the body is reduced, and it becomes a tape for semiconductor processing with better antistatic performance.

For semiconductor processing tapes, for the purpose of protecting the adhesive layer, a transparent spacer can be placed on the surface of the adhesive layer. The separator is preferably laminated on the surface of the adhesive layer. As the material of the separator, for example, paper, plastic film, etc. can be used. From the viewpoint of excellent surface smoothness, it is preferable to use a plastic film. The plastic film used as a separator is not particularly limited as long as it can protect the above-mentioned adhesive layer, and examples thereof include polyethylene, polypropylene, polyethylene terephthalate, and polybutene.

＜Adhesive composition＞ The adhesive layer which the tape for semiconductor processing of this embodiment has is a hardened|cured material of an adhesive composition. Hereinafter, in the semiconductor processing tape of this embodiment, the adhesive composition used as the material of the adhesive layer will be described in detail. The adhesive composition system of this embodiment includes polyurethane (A), (meth)acrylate monomer (B), chain transfer agent (C), and photopolymerization initiator (D) .

(Polyurethane (A)) The polyurethane (A) includes the polyurethane (a1) described later. The polyurethane (A) is not only the polyurethane (a1), but for the purpose of adjusting the cohesive force of the cured product in the adhesive composition, the polyurethane (a2) described later may be included. It is preferable that the polyurethane (A) does not contain components other than the polyurethane (a1) and the polyurethane (a2) contained if necessary.

[Polyurethane (a1)] The polyurethane (a1) has a skeleton containing a structure derived from a polyoxyalkylene polyol and a structure derived from a polyisocyanate. In addition, the polyurethane (a1) has a (meth)acryloyl group at the plural ends. The terminal (meth)acryloyl group possessed by the polyurethane (a1) is preferably a part of the (meth)acryloyloxy group.

In the present invention, the so-called "plural ends" of polyurethane means that when the polyurethane is a linear polymer, there are two ends, and when the polyurethane is a branched polymer, Two or more of the ends of the same number as the number of branches in each chain. In addition, in the present invention, the so-called (meth)acryloyl group refers to a _{functional group represented by the chemical formula CH 2} =CH-CO- and a functional group represented by the chemical formula CH ₂ =C(CH ₃ )-CO- One or more of functional groups.

[Polyurethane (a2)] The polyurethane (a2) is the same as the polyurethane (a1), and has a skeleton containing a structure derived from a polyoxyalkylene polyol and a structure derived from a polyisocyanate. The polyurethane (a2) is different from the polyurethane (a1) in that it has a (meth)acryloyl group only at one end. The terminal (meth)acryloyl group possessed by the polyurethane (a2) is preferably a part of the (meth)acryloyloxy group. Polyurethane (a2) does not have a (meth)acrylic acid terminal, and preferably has a structure selected from an isocyanate group, a structure derived from an alkyl alcohol, and a structure derived from an alkyl isocyanate One of the group, more preferably has a structure derived from an alkyl alcohol.

"From the structure of polyoxyalkylene polyol" As the polyoxyalkylene polyol having a structure derived from the polyoxyalkylene polyol contained in the skeleton of the polyurethane (a1) and the polyurethane (a2), it is preferable to have Alkylene chain with 2~4 carbons. As a specific example, polyoxyethylene polyol, polyoxypropylene polyol, polyoxybutylene polyol, etc. are mentioned.

The polyoxyalkylene polyol derived from the structure of the polyoxyalkylene polyol may include one type of alkylene chain or two or more types of alkylene chain. The polyoxyalkylene polyol derived from the structure of the polyoxyalkylene polyol is preferably one having 2 or 3 hydroxyl groups at the end (diol type or triol type polyoxyalkylene polyol ), more preferably polyoxyalkylene glycol (diol type), particularly preferably polypropylene glycol having an alkylene chain with 3 carbon atoms.

For example, when the polyoxyalkylene polyol is polypropylene glycol, the hydroxyl value is preferably 20 to 120 mgKOH/g, more preferably 30 to 100 mgKOH/g, and still more preferably 40 to 80 mgKOH/g. As a specific example of polypropylene glycol, for example, polypropylene glycol (Actcol D-2000; manufactured by Mitsui Chemicals, number average molecular weight 2000, glycol type) having a hydroxyl group (Hydroxy) with a hydroxyl value of 56 mgKOH/g at the terminal can be cited.

Here, the hydroxyl value of the polyoxyalkylene polyol is the hydroxyl value of the polyoxyalkylene polyol measured in accordance with JISK0070. That is, the number of mg of potassium hydroxide is necessary to neutralize free acetic acid during acetylation of 1 g of polyoxyalkylene polyol. Specifically, it can be obtained by using acetic anhydride, acetylating the hydroxyl group in the sample (polyoxyalkylene polyol), and titrating the free acetic acid produced at this time with a potassium hydroxide solution.

The number average molecular weight of the polyoxyalkylene polyol is preferably 500 to 5,000, more preferably 800 to 4,000, and still more preferably 1,000 to 3,000. When the number average molecular weight of the polyoxyalkylene polyol is 500 or more, the hardened product containing the adhesive composition using the synthesized polyurethane (A), that is, a semiconductor processing tape with an adhesive layer, becomes High peel strength. In addition, when the number average molecular weight of the polyoxyalkylene polyol is 5,000 or less, the synthesized polyurethane (A) is used to contain a sufficient amount of urethane bonds. Therefore, the hardened material obtained by hardening the adhesive composition containing polyurethane (A) has good cohesive force.

The structure derived from the polyoxyalkylene polyol contained in the skeleton of polyurethane (a1) and polyurethane (a2), each may be only one type, or may include two or more types的结构。 The structure. The polyurethane (a1) and the polyurethane (a2) may have a structure derived from two or more different polyoxyalkylene polyols as a structure in which a structure derived from a polyisocyanate is pinched and bonded. The structure derived from the polyoxyalkylene polyol contained in the skeleton of the polyurethane (a1), and the polyoxyalkylene polyol contained in the skeleton derived from the polyurethane (a2) The structure can be the same or different.

"Structure derived from polyisocyanate" As the polyisocyanate derived from the structure of the polyisocyanate contained in the skeleton of the polyurethane (a1) and the polyurethane (a2), a compound having a plurality of isocyanate groups is used, and it is preferably used Diisocyanate. Examples of diisocyanates include tolylene diisocyanate and its hydrogen additives, xylylene diisocyanate and its hydrogen additives, diphenylmethane diisocyanate and Its hydrogen additives, 1,5-naphthylene diisocyanate and its hydrogen additives, hexamethylene diisocyanate, trimethyl hexamethylene diisocyanate, tetramethyl tolylene diisocyanate, isocyanate Phosphonone diisocyanate, 4,4'-dicyclohexyl diisocyanate, 1,3-bis(isocyanate methyl)cyclohexane, norbornane diisocyanate, etc.

Among these polyisocyanates, from the viewpoint of the light resistance of the synthesized polyurethane (A) and the control of the reactivity with polyoxyalkylene polyols, it is preferable to use isophores Hydrogen addition of ketone diisocyanate or diphenylmethane diisocyanate. In addition, from the viewpoint of reactivity with polyoxyalkylene polyol, it is more preferable to use a hydrogen additive of diphenylmethane diisocyanate.

Specific examples of the polyisocyanate derived from the structure of the polyisocyanate include hydrogen additives of diphenylmethane diisocyanate (Desmodur W, manufactured by Sumika Covestro Urethane), isophorone diisocyanate (Desmodur I, Sumka Covestro Urethane), etc.

The structure derived from the polyisocyanate contained in the skeleton of the polyurethane (a1) and the polyurethane (a2) may be only one type each, or a structure including two or more types. In addition, the so-called structure derived from the polyisocyanate contained in the skeleton of the polyurethane (a1) and the structure derived from the polyisocyanate contained in the skeleton of the polyurethane (a2) may be the same. Can be different.

Preferably, the structure derived from the polyisocyanate contained in the skeleton of the polyurethane (a1) and the polyurethane (a2) and the structure derived from the polyoxyalkylene polyol are the same. In this case, the polyurethane (a1) and the polyurethane (a2) can be synthesized at the same time because the polyurethane (A) can be produced efficiently.

The ratio of the polyurethane (a1) contained in the polyurethane (A) is preferably 80-100% of the polyurethane (A) based on the number of molecules, more preferably 90 ~100%, more preferably 100%. The ratio of the polyurethane (a2) contained in the polyurethane (A) is preferably 0-20% of the polyurethane (A) based on the number of molecules, more preferably 0 ~10%, more preferably 0%. When the proportion of the polyurethane (a1) contained in the polyurethane (A) is 80% or more, the cured product of the adhesive composition containing the polyurethane (A) becomes sufficiently The greater cohesion is better.

The total number of ends contained in the polyurethane (A) (the number of ends of the polyurethane (a1), and the number of ends of the polyurethane (a2) contained if necessary Among them, based on the number of molecules, it is preferable to introduce (meth)acrylic acid groups at 90-100%, more preferably at 95-100%, and even more preferably at 100%. Among all the terminal numbers contained in the polyurethane (A), when the introduction amount of the (meth)acrylic group is 90% or more based on the number of molecules, the hardening contains the polyurethane (A) The cohesive force of the cured product obtained from the adhesive composition becomes sufficiently high.

Among all the terminal numbers contained in the polyurethane (A), the ratio of the number of (meth)acrylic acid groups introduced based on the number of molecules can be used to analyze the results of the polyurethane (A) Figure out. As the analysis method, for example, infrared absorption spectroscopy (IR) method, nuclear magnetic resonance spectroscopy (NMR) method, etc. are mentioned.

The ratio of the content of the polyurethane (a1) contained in the polyurethane (A) to the polyurethane (a2), that is, the polyurethane (A) contains Among the total number of ends, the ratio of the number of (meth)acrylic acid groups introduced based on the number of molecules can be adjusted by the production method of the polyurethane (A) described later.

The mass average molecular weight of the polyurethane (A) is preferably 30,000 to 200,000, more preferably 50,000 to 150,000, and still more preferably 60,000 to 100,000. When the mass average molecular weight of the polyurethane (A) is 30,000 or more, the cured product obtained by curing the adhesive composition containing the polyurethane (A) has good flexibility. In addition, when the mass average molecular weight of the polyurethane (A) is 200,000 or less, the adhesive composition containing the polyurethane (A) is easy to handle and has good workability.

(Method for measuring the mass average molecular weight of polyurethane (A)) The mass average molecular weight of polyurethane (A) is polystyrene measured by gel/permeation chromatography (GPC-101; Shodex (registered trademark) manufactured by Showa Denko Co., Ltd.) (hereinafter referred to as GPC) The converted value. The measurement conditions of GPC are as follows. Column: LF-804 (manufactured by Showa Denko Co., Ltd.) Column temperature: 40℃ Sample: 0.2% by mass tetrahydrofuran solution of polyurethane (A) Flow rate: 1ml/min Eluent: Tetrahydrofuran Detector: RI detector (differential refractive index detector)

The content of polyurethane (A) in the adhesive composition of this embodiment is preferably 20-50% by mass, more preferably 25-45% by mass, and still more preferably 30-40% by mass . When the content of the polyurethane (A) is 20% by mass or more, the cured product obtained by curing the adhesive composition has sufficient cohesive force, and excellent adhesive force is obtained. In addition, for semiconductor processing tapes that use this cured product as an adhesive layer, the flexibility of the adhesive layer is within a proper range, and it is difficult to pinch air bubbles between the adhesive layer and the adherend. In addition, when the content of the polyurethane (A) is 50% by mass or less, the cured product obtained by curing the adhesive composition has sufficient flexibility. Accordingly, the tape for semiconductor processing that uses this hardened product as an adhesive layer has good wettability to the adherend.

((Meth)acrylate monomer (B)) The (meth)acrylate monomer (B) contains a monofunctional (meth)acrylate and a polyfunctional (meth)acrylate in addition to the polyurethane (A).

In the present invention, the term "monofunctional" in the monofunctional (meth)acrylate means a (meth)acrylate having only one (meth)acryloxy group. In addition, in the present invention, the term "multifunctional" in the multifunctional (meth)acrylate means a (meth)acrylate in which the number of (meth)acryloxy groups is 2 or more.

As the (meth)acrylate monomer (B), it is preferable to combine a monofunctional (meth)acrylate from the viewpoints of the cohesive force of the cured product obtained by curing the adhesive composition and the curability of the adhesive composition Used with multifunctional (meth)acrylates. More preferably, it contains monofunctional (meth)acrylate and trifunctional or more (meth)acrylate. In particular, it is most preferable to contain a monofunctional (meth)acrylate and a trifunctional (meth)acrylate having 3 (meth)acryloyloxy groups.

Examples of monofunctional (meth)acrylates include cyclic alkyl (meth)acrylates and alkoxyalkyl (meth)acrylates such as alkyl (meth)acrylates, isobornyl (meth)acrylates, etc. Meth) acrylate, alkoxy (poly) alkylene glycol (meth)acrylate, hydroxyl-containing (meth)acrylate, carboxyl-containing (meth)acrylate, fluorinated alkyl (meth)acrylate (Meth)acrylic acid ester, dialkylaminoalkyl (meth)acrylate, (meth)acrylamide, epoxy-containing (meth)acrylate, (meth)acrylomorpholine, etc. These may be used individually by 1 type, and may mix and use 2 or more types.

Among these monofunctional (meth)acrylates, it is preferable to contain an alkyl (meth)acrylate. This is because the adhesive force (peeling force) and gel fraction of the cured product obtained by curing the adhesive composition tend to be in a more proper range when the cured product is used as the adhesive layer of the tape for semiconductor processing. As the alkyl (meth)acrylate, it is more preferable to use an alkyl (meth)acrylate having an alkyl group having 4 to 10 carbon atoms. Specifically, as the alkyl (meth)acrylate, methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, 2-ethylhexyl (Meth)acrylate and the like. Among these, it is particularly preferable to use 2-ethylhexyl (meth)acrylate and/or n-butyl (meth)acrylate.

In addition to the polyfunctional (meth)acrylate-based polyurethane (A), a compound having plural (meth)acryloxy groups. As the polyfunctional (meth)acrylate, it is preferable to use poly(meth)acrylate of a polyol compound. As the polyfunctional (meth)acrylate, specifically, polyethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylic acid Ester, triethylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, hydroxypivalate neopentyl glycol di(meth)acrylate, 1,3-bis(hydroxyethyl) )-5,5-Dimethylhydantoin di(meth)acrylate, α,ω-bis(meth)acryloyl bis-diethylene glycol phthalate, trimethylolpropane Tri(meth)acrylate, ethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6 -Hexanediol di(meth)acrylate, diacryloxyethyl phosphate, pentaerythritol tetra(meth)acrylate, etc. Among these, as the polyfunctional (meth)acrylate, it is preferable to use trimethylolpropane tri(meth)acrylate from the viewpoint of the curability of the adhesive composition. These polyfunctional (meth)acrylates may be used alone or in combination of two or more.

When the ratio of monofunctional (meth)acrylate and polyfunctional (meth)acrylate is set to 100 mol% in total of (meth)acrylate monomer (B), it is preferable to contain monofunctional (meth)acrylate Base) acrylate 85~99 mol%, polyfunctional (meth)acrylate 1~15 mol%. In this case, the content of the monofunctional (meth)acrylate is more preferably 90-99 mol%, and still more preferably 95-98 mol%. In addition, the content of the polyfunctional (meth)acrylate is more preferably 1-10 mol%, and still more preferably 2-5 mol%.

When the content of monofunctional (meth)acrylate is 85 mol% or more, the fluidity of the cured product obtained by curing the adhesive composition is better when the cured product is used as the adhesive layer of the tape for semiconductor processing. Range. Accordingly, the tape for semiconductor processing using this hardened product as an adhesive layer has sufficient unevenness absorbability, and when it is attached to an adhered body with uneven portions on the surface, it is preferably between the uneven portions of the adhered body It is difficult to generate voids. In addition, when the content of monofunctional (meth)acrylate is 99 mol% or less, it is preferable to use the cured product of the adhesive composition as an adhesive layer for semiconductor processing tapes, and the paste remains when peeled from the adherend difficulty.

When the content of the polyfunctional (meth)acrylate is 1 mol% or more, it is preferable that the fluidity of the cured product obtained by curing the adhesive composition is not too large. In addition, when the content of the polyfunctional (meth)acrylate is 15 mol% or less, the fluidity of the cured product obtained by curing the adhesive composition becomes when the cured product is used as the adhesive layer of the tape for semiconductor processing. The preferred range. Accordingly, the tape for semiconductor processing that uses the hardened material as the adhesive layer has sufficient concavity and convexity absorbability, and when it is attached to a substrate with concavity and convexity on the surface, it is preferably on the concavity and convexity of the substrate. It is difficult to create gaps between them.

The content of the (meth)acrylate monomer (B) in the adhesive composition of this embodiment is preferably 35 to 79 mass%, more preferably 40 to 73 mass%, and still more preferably 45 to 66 quality%. When the content of the (meth)acrylate monomer (B) is 35% by mass or more, since the viscosity of the adhesive composition does not increase too much, it is preferable to have excellent paintability. In addition, when the content of the (meth)acrylate monomer (B) is 79% by mass or less, it is preferable that the viscosity of the adhesive composition does not decrease too much, and it is easy to control the thickness of the coating film formed by the adhesive composition .

(Chain transfer agent (C)) The chain transfer agent (C) is contained in the adhesive composition for the purpose of controlling the concavity and convexity absorbency and the gel fraction of the hardened product that hardens the adhesive composition. As the chain transfer agent (C), it is preferable to use a thiol compound. In particular, polyfunctional thiols can be preferably used. Multifunctional thiol is a compound having two or more mercapto groups in the molecule.

Although not particularly limited as the polyfunctional thiol, for example, 1,2-ethane dithiol, 1,4-bis(3-mercaptobutoxy)butane, tetraethylene glycol bis(3 -Mercaptopropionate), Trimethylolethane Ginseng (3-mercaptobutyrate), Trimethylolpropane Ginseng (3-mercaptobutyrate), Trimethylolpropane Ginseng (3-mercaptopropionic acid Esters), pentaerythritol 4 (3-mercaptobutyrate), pentaerythritol 4 (3-mercaptopropionate), 1,3,5-ginseng (3-mercaptobutoxyethyl)-1,3,5-tri Oxazine-2,4,6(1H,3H,5H)-triketone, ginseng-[(3-mercaptopropionyloxy)-ethyl]-isocyanurate, dipentaerythritol (3-mercaptopropionic acid) Ester) and so on. As the chain transfer agent (C), among the above, pentaerythritol 4 (3-mercaptobutyrate) is preferably used from the viewpoint of the reactivity of the adhesive composition.

The content of the chain transfer agent (C) in the adhesive composition of the present embodiment is preferably 0.5 to 8% by mass, more preferably 1 to 5% by mass, and still more preferably 3 to 4.5% by mass. When the content of the chain transfer agent (C) is 0.5% by mass or more, the fluidity of the cured product obtained by curing the adhesive composition becomes a preferable range when the cured product is used as the adhesive layer of the tape for semiconductor processing. Accordingly, it is preferable that a tape for semiconductor processing that uses a hardened product as an adhesive layer has sufficient unevenness absorbability, and it is difficult to generate voids between the uneven portions of the adherend. When the content is 8% by mass or less, it is preferable that when the tape for semiconductor processing using the cured product of the adhesive composition as the adhesive layer is peeled from the adherend, it is difficult for the paste to remain.

(Photopolymerization initiator (D)) Although the photopolymerization initiator (D) is not particularly limited, it is preferably a photoradical polymerization initiator. As the photopolymerization initiator (D), for example, a carbonyl-based photopolymerization initiator, a sulfide-based photopolymerization initiator, an phosphine oxide-based photopolymerization initiator, a quinone-based photopolymerization initiator, Sulfonyl chloride-based photopolymerization initiator, thioxanthone-based photopolymerization initiator, etc. Among these photopolymerization initiators (D), from the viewpoint of transparency of the cured product obtained by photocuring the adhesive composition, it is preferable to use a carbonyl-based photopolymerization initiator and/or phosphine Oxide-based photopolymerization initiator. Specifically, it is more preferable to use 2,4,6-trimethylbenzyl diphenyl phosphine oxide agent and/or 1-hydroxycyclohexyl-phenyl ketone.

The content of the photopolymerization initiator (D) in the adhesive composition of the present embodiment is preferably 0.01 to 5% by mass, more preferably 0.05 to 3% by mass, and still more preferably 0.1 to 2% by mass. When the content of the photopolymerization initiator (D) is 0.01% by mass or more, the photocuring of the adhesive composition is sufficiently performed. In addition, when the content of the photopolymerization initiator (D) is 5% by mass or less, the low-molecular-weight components will not increase too much during the photocuring of the adhesive composition. Therefore, it is preferable that when the tape for semiconductor processing which uses the cured product of the adhesive composition as the adhesive layer is peeled from the adherend, it is difficult for the paste to remain.

(Fatty acid ester (E)) The adhesive composition system of this embodiment includes polyurethane (A), (meth)acrylate monomer (B), chain transfer agent (C), and photopolymerization initiator (D) , And if necessary, fatty acid ester (E) may be contained. Fatty acid ester (E) is used to control the adhesive force of the adhesive layer of the hardened material of the adhesive composition in the semiconductor processing tape, and to improve the lamination (wetness) of the adhesive layer and the removal of air bubbles ( It is included in the adhesive composition for the purpose of easy removal of trapped air bubbles when the adherend is attached to the tape for semiconductor processing.

As fatty acid ester (E), an ester of fatty acid and alkyl alcohol can be used. In addition, from the viewpoint of compatibility with other components, it is preferable to use esters selected from fatty acids with 8 to 18 carbons and monofunctional alcohols having branched hydrocarbon groups with 3 to 18 carbons, and 14 to 14 carbons. Fatty acid esters in the group formed by 18 unsaturated fatty acids and 2~4 functional alcohol esters.

Examples of esters of fatty acids with 8 to 18 carbons and monofunctional alcohols having branched hydrocarbon groups with 3 to 18 carbons include isostearyl laurate, isopropyl myristate, isocetyl myristate, Octyl dodecyl myristate, isopropyl palmitate, isostearyl palmitate, isocetyl stearate, 2-ethylhexyl stearate, octyl dodecyl oleate, hexamethylene Diisostearyl acid, diisocetyl sebacate, trioleyl trimellitate and triisocetyl trimellitate, etc. Among these, it is preferable to use isopropyl myristate, isopropyl palmitate, 2-ethylhexyl stearate, and particularly preferably to use isopropyl myristate and/or 2-ethyl stearate.基hexyl ester.

Examples of esters of unsaturated fatty acids with 14 to 18 carbon atoms and 2 to 4 functional alcohols include unsaturated fatty acids such as myristic acid, oleic acid, linoleic acid, linolenic acid, isopalmitic acid, and isostearic acid , Ester with alcohols such as ethylene glycol, propylene glycol, glycerin, trimethylolpropane, pentaerythritol and sorbitol.

The content of the fatty acid ester (E) in the adhesive composition of this embodiment is preferably 3-18% by mass, more preferably 5-15% by mass. When the content of fatty acid ester (E) is 3% by mass or more, the hardened product of the adhesive composition is used as the adhesive layer. The adhesive force of the tape for semiconductor processing is in a preferable range, and the adhesive layer is laminated The performance and the removal of air bubbles become better. When the content of the fatty acid ester (E) is 18% by mass or less, it is preferable that when the tape for semiconductor processing using the cured product of the adhesive composition as the adhesive layer is peeled from the adherend, it is difficult to produce the fatty acid ester ( E) The paste remains.

(Solvent) Although the adhesive composition of the present embodiment may contain a solvent, it is more preferably a solvent-free one that does not substantially contain a solvent. When the adhesive composition of this embodiment contains a solvent, for example, a solvent can be used as a leveling agent and/or a softening agent.

When the adhesive composition of the present embodiment is solvent-free, when using this to form the adhesive layer of the tape for semiconductor processing, the step of heating and drying the solvent can be omitted, resulting in excellent productivity. In particular, when the adhesive composition of this embodiment is used to manufacture a semiconductor processing tape having an adhesive layer with a thickness of more than 50 μm, the productivity improvement effect becomes significant due to the omission of the step of heating and drying the solvent. It is preferably solvent-free.

In the present invention, the meaning of "substantially not containing a solvent" in the adhesive composition means that the content of the solvent in the adhesive composition is 0 to 1% by mass, preferably 0 to 0.5% by mass, and more preferably 0~0.1% by mass.

(other) The adhesive composition of this embodiment may contain other additives if necessary in a range that does not impair the effects of the present invention. Examples of additives include plasticizers, surface lubricants, antioxidants, anti-aging agents, light stabilizers, ultraviolet absorbers, polymerization inhibitors, benzotriazole-based light stabilizers, phosphate esters, and other flame retardants. Agents, dyes, etc.

<Method of manufacturing adhesive composition> Next, the method of manufacturing the adhesive composition of the present embodiment will be described in detail with examples. Hereinafter, among the components included in the adhesive composition of the present embodiment, examples are given for polyurethane (A) and a preferable synthesis method. Among the components contained in the adhesive composition of this embodiment, the (meth)acrylate monomer (B), chain transfer agent (C), photopolymerization initiator (D), fatty acid ester (E), etc. , Remove all components of polyurethane (A), and can easily buy commercially available products. In addition, the individual synthesis methods differ depending on the type of compound used as each component. Therefore, the description of the synthesis method is omitted.

＜Synthesis method of polyurethane (A)＞ Hereinafter, an example of a preferable method for synthesizing polyurethane (A) contained in the adhesive composition of the present embodiment will be described. However, the synthesis method of polyurethane (A) is not limited to the synthesis method shown below, and the conditions such as the raw materials and equipment used in the synthesis can be changed as appropriate.

In the synthesis method of polyurethane (A) shown below, the reaction between hydroxyl and isocyanate groups can be urethane-formated in the presence of an inert organic solvent even in any step. The catalyst is carried out. Examples of this urethane catalyst include dibutyltin dilaurate, dibutyltin diethylhexanoate, and dioctyltin dilaurate. Moreover, it is preferable that the reaction of a hydroxyl group and an isocyanate group can be continued for 1 to 5 hours at 30-100 degreeC even in any step. The amount of the urethane catalyst used is preferably 50 to 500 ppm by mass relative to the total mass of the reactants (raw materials).

In the synthesis of polyurethane (A), first, the polyoxyalkylene polyol and polyisocyanate are made into a relatively hydroxyl group based on the amount of isocyanate groups (based on the number of molecules, the same below) (based on the number of molecules, the same below) Place more proportions. Then, the polyoxyalkylene polyol and the polyisocyanate are reacted to synthesize a polyurethane having an isocyanate group at the end as a polyurethane (A) precursor. Specific examples of polyoxyalkylene polyols and polyisocyanates used as raw materials are as exemplified in the section of polyurethane (A).

At this time, by adjusting the ratio of the amount of isocyanate groups to the amount of hydroxyl groups contained in the raw material, the molecular weight (degree of polymerization) of the polyurethane having an isocyanate group at the terminal can be adjusted. Specifically, the smaller the excess of the amount of isocyanate groups with respect to the amount of hydroxyl groups, the larger the molecular weight of the polyurethane having an isocyanate group at the terminal. In addition, the larger the excess of the amount of isocyanate groups relative to the amount of hydroxyl groups, the smaller the molecular weight of the polyurethane having an isocyanate group at the terminal. In this embodiment, by adjusting the molecular weight of the polyurethane having an isocyanate group at the terminal, the mass average molecular weight of the target polyurethane (A) is adjusted.

Next, the polyurethane having an isocyanate group at the end is reacted with a compound having a hydroxyl group and a (meth)acrylic group to produce a polyurethane containing polyurethane (a1) (A). The polyurethane (a1) has a skeleton including a structure derived from a polyoxyalkylene polyol and a structure derived from a polyisocyanate, and has a (meth)acryloyl group at a plurality of ends. The terminal (meth)acryloyl group of the produced polyurethane (A) is preferably a part of the (meth)acryloyloxy group.

Although the compound having a hydroxyl group and a (meth)acryloyl group is not particularly limited, examples include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, and 4-hydroxyl Hydroxyalkyl (meth)acrylates such as butyl (meth)acrylate; 1,3-butanediol mono(meth)acrylate, 1,4-butanediol mono(meth)acrylic acid Esters, 1,6-hexanediol mono(meth)acrylate, 3-methylpentanediol mono(meth)acrylate, etc., which have (meth)acrylic acid groups derived from various polyols Mono-alcohol and so on. The compound having these hydroxyl groups and (meth)acrylic groups may be used alone or in combination of two or more kinds. Among the compounds having these hydroxyl groups and (meth)acrylic groups, from the point of view of the reactivity with the isocyanate group of the polyurethane having an isocyanate group at the end and the photocurability of the adhesive composition Preferably, 2-hydroxyethyl (meth)acrylate is used.

In addition, polyurethane (A) can be used in combination with a compound having a hydroxyl group and a (meth)acryloyl group and an alkyl alcohol that does not have a (meth)acryloyl group and has one hydroxyl group, and The polyurethane having an isocyanate group at the end reacts and is produced. As the alkyl alcohol, as long as it does not have a (meth)acrylic acid group and has one hydroxyl group, linear, branched, alicyclic alkyl alcohols, etc. can be used, and they are not particularly limited. The said alkyl alcohol may be used individually by 1 type, and may be used in combination of 2 or more types.

By combining a compound having a hydroxyl group and a (meth)acrylic acid group, an alkyl alcohol that does not have a (meth)acrylic acid group and having one hydroxyl group, and a polyurethane having an isocyanate group at the end The reaction proceeds to produce polyurethane (A), and the introduction amount of the (meth)acrylic acid group relative to the polyurethane having an isocyanate group at the terminal can be adjusted.

In more detail, according to the above-mentioned reaction, a polyurethane (A) containing plural kinds of polyurethanes having different introduction amounts of the terminal (meth)acrylic groups is produced. Among the plural kinds of polyurethanes, the polyurethanes (a1) having (meth)acrylic groups at the ends of the plurality are included. Furthermore, among the plural kinds of polyurethanes, not only the polyurethane (a1), but also at least a part of the plurality of terminals are polyamine groups having a structure derived from the above-mentioned alkyl alcohol. Formate. According to this, among the plurality of types of polyurethanes produced, at least a part of the ends including the plurality of ends is a polyurethane that does not have a (meth)acryloyl group. Furthermore, the polyurethane (a2) which has a (meth)acrylic acid group only at one terminal among the multiple types of produced polyurethane may be included.

<Other examples of synthetic methods of polyurethane (A)> Next, another example of a preferable synthesis method of polyurethane (A) will be described. Even in the synthesis method of polyurethane (A) shown below, it is the same as the example of the above synthesis method. The reaction of hydroxyl group and isocyanate group, even in any step, in the presence of an inert organic solvent, It is also carried out using a urethane catalyst for isocyanate groups. Examples of the urethane catalyst include dibutyltin dilaurate, dibutyltin diethylhexanoate, and dioctyltin dilaurate. Moreover, it is preferable that the reaction of a hydroxyl group and an isocyanate group can be continued for 1 to 5 hours at 30-100 degreeC even in any step. The amount of the urethane catalyst used is preferably 50 to 500 ppm by mass relative to the total mass of the reactants (raw materials).

Using this synthesis method, when synthesizing polyurethane (A), unlike the example of the above-mentioned synthesis method, it is synthesized before the polyurethane (A) with a hydroxyl group at the end is synthesized Drive body. Specifically, first, the polyoxyalkylene polyol and the polyisocyanate are placed in such a ratio that the amount of hydroxyl groups (based on the number of molecules, the same below) is greater than the amount of isocyanate groups (based on the number of molecules, the same below). Then, the polyoxyalkylene polyol and the polyisocyanate are reacted to synthesize a polyurethane having a hydroxyl group at the terminal as a precursor of the polyurethane (A).

At this time, by adjusting the ratio of the amount of hydroxyl groups to the amount of isocyanate groups contained in the raw material, the molecular weight (degree of polymerization) of the polyurethane having a hydroxyl group at the terminal can be adjusted. Specifically, the smaller the excess of the amount of hydroxyl groups relative to the amount of isocyanate groups, the larger the molecular weight of the polyurethane having a hydroxyl group at the terminal. In addition, the larger the excess of the amount of hydroxyl groups relative to the amount of isocyanate groups, the smaller the molecular weight of the polyurethane having a hydroxyl group at the terminal. In this embodiment, by adjusting the molecular weight of the polyurethane having a hydroxyl group at the terminal, the mass average molecular weight of the target polyurethane (A) is adjusted.

Secondly, the polyurethane having a hydroxyl group at the end is reacted with a compound having an isocyanate group and a (meth)acrylic acid group to have a structure containing polyoxyalkylene polyols and polyisocyanate-derived The skeleton of the structure of, produces a polyurethane (A) containing a polyurethane (a1) having a (meth)acryloyl group at the plurality of ends. The terminal (meth)acryloyl group of the produced polyurethane (A) is preferably a part of the (meth)acryloyloxy group.

Although not particularly limited as the compound having an isocyanate group and a (meth)acryloyl group, examples include 2-(meth)acryloyloxyethyl isocyanate and 2-(meth)acryloyloxypropyl Isocyanate, 1,1-bis(acryloxymethyl)ethyl isocyanate, etc. Moreover, as a commercial product of the compound which has an isocyanate group and a (meth)acryloyl group, for example, Karenz MOI (registered trademark) manufactured by Showa Denko Co., Ltd., Karenz AOI (registered trademark), etc. can be exemplified. These compounds having an isocyanate group and a (meth)acryloyl group may be used alone or in combination of two or more kinds. Among these compounds having isocyanate groups and (meth)acrylic groups, from the viewpoint of the reactivity with the hydroxyl group of the polyurethane having a hydroxyl group at the end, and the photocurability of the adhesive composition Preferably, 2-(meth)acryloyloxyethyl isocyanate is used.

In addition, polyurethane (A) can be used in combination with a compound having an isocyanate group and a (meth)acryloyl group, and an alkyl isocyanate that does not have a (meth)acryloyl group and has one isocyanate group , It reacts with polyurethane having a hydroxyl group at the end to produce it. As the alkyl isocyanate, as long as it does not have a (meth)acryloyl group and has one isocyanate group, linear, branched, alicyclic alkyl isocyanate, etc. can be used, and it is not particularly limited. . The said alkyl isocyanate may be used individually by 1 type, and may be used in combination of 2 or more types.

By combining a compound having an isocyanate group and a (meth)acrylic acid group, an alkyl isocyanate having no (meth)acrylic acid group and having one isocyanate group, and a polyurethane formic acid having a hydroxyl group at the end The ester reacts to produce polyurethane (A), and the introduction amount of the (meth)acrylic group relative to the polyurethane having a hydroxyl group at the terminal can be adjusted.

In more detail, according to the above-mentioned reaction, a polyurethane (A) containing plural kinds of polyurethanes having different introduction amounts of the terminal (meth)acrylic groups is produced. Among the plural kinds of polyurethanes, the polyurethanes (a1) having (meth)acrylic groups at the ends of the plurality are included. Furthermore, among the plural kinds of polyurethanes, not only the polyurethane (a1), but also the plurality of terminals at least part of which are polyamine groups having a structure derived from the above-mentioned alkyl isocyanate are included. Formate. Accordingly, among the plurality of types of polyurethanes produced, at least a part of the ends including the plurality of ends is a polyurethane that does not have a (meth)acryloyl group. Furthermore, the polyurethane (a2) which has a (meth)acrylic acid group only at one terminal among the multiple types of produced polyurethane may be included.

<How to mix the components contained in the adhesive composition> The adhesive composition of this embodiment can be obtained by mixing polyurethane (A) obtained by the above-mentioned synthesis method, with (meth)acrylate monomer (B), and chain transfer agent (C). ), with photopolymerization initiator (D), fatty acid ester (E) and other additives if necessary. The method of mixing each component contained in the adhesive composition of this embodiment is not specifically limited, For example, it can use the stirring apparatus equipped with the stirring blades, such as a homogeneous disperser, a blade.

＜Manufacturing method of tape for semiconductor processing＞ Next, the manufacturing method of the tape for semiconductor processing of this embodiment is demonstrated. The manufacturing method of the tape for semiconductor processing of this embodiment is not specifically limited, It can manufacture using a well-known method. For example, fine particles of polypyrrole and/or polypyrrole derivatives are dispersed in a hydrophilic solvent using a polymer dispersant and/or dopant, and then mixed with a water-soluble or water-dispersible binder resin to prepare a resin Composition: After coating this resin composition on a base body such as a polymer film, it is dried to remove the solvent to obtain a base material forming an antistatic layer. Then, the adhesive composition is coated on the antistatic layer of the substrate, and a transparent separator film is laminated to form a laminate. Then, ultraviolet rays are irradiated to the adhesive composition through the partition plate to light-harden the adhesive composition. In this way, a tape for semiconductor processing in which an adhesive layer of a cured product of the adhesive composition is formed on a substrate having an antistatic layer is obtained.

The method of applying the adhesive composition to the substrate is not particularly limited, and can be appropriately selected. For example, as a method of coating the adhesive composition on the substrate, the use of a gravure roll coater, a reverse roll coater, a roll coater, a dip coater, a bar coater, a knife coater, and spray coating can be cited. Coating machine, cut-off wheel coater, direct coater and other coating machine methods, screen printing method, etc.

Examples of the light source when the adhesive composition is cured by light include backlights, low-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, metal halide lamps, xenon lamps, and the like. The intensity of light irradiation is preferably such that the adhesive composition can be sufficiently hardened, and the gel fraction of the hardened product is preferably in the range of 50 to 65% by mass. For example, it is preferably 50 to 3000 mW/cm ² . However, when the intensity of light irradiation is weak, it takes time to harden and reduces productivity.

In this embodiment, although the adhesive composition is irradiated with ultraviolet rays through a transparent separator, when the substrate is transparent, ultraviolet rays can be irradiated from the substrate side, and as the separator, an opaque one can be used.

＜The use of tape for semiconductor processing and the performance sought＞ The tape for semiconductor processing of the present embodiment can be used, for example, for the purpose of attaching an object having uneven portions on the surface, and then peeling it off. Specifically, it can be used as a back polishing tape for semiconductor wafer processing that is attached to the surface formed by bumps of a semiconductor wafer, protects the surface of the semiconductor wafer, and peels off after a specified wafer processing step.

When the tape for semiconductor processing of this embodiment is used to protect the surface of a semiconductor wafer on which bumps are formed, the peel strength (adhesion) of the tape for semiconductor processing, for example, the back surface in the processing step of a semiconductor device In the polishing step, it is necessary for the semiconductor wafer to have the peel strength (adhesion) that is firmly fixed by the semiconductor processing tape. On the other hand, the peel strength of the tape for semiconductor processing must be such that it does not damage the components of the semiconductor device when the tape for semiconductor processing is peeled from the semiconductor wafer after a specified processing step.

From these viewpoints, the peel strength of the semiconductor processing tape used in the above-mentioned applications is at a peeling speed of 0.3m/min. When the thickness of the adhesive layer is 50 to 200 μm, it is preferably 10 to 300 gf/25mm. It is more preferably 15~200gf/25mm, and still more preferably 20~150gf/25mm. When the thickness of the adhesive layer is 200 to 500 μm, it is preferably 50 to 500 gf/25 mm, more preferably 60 to 400 gf/25 mm, and still more preferably 70 to 300 gf/25 mm. The specific measuring method of the peeling strength of the tape for semiconductor processing is mentioned later in an Example.

The tape for semiconductor processing of the present embodiment is on the side of the base material forming the antistatic layer, and has an adhesive layer of a cured product of the adhesive composition of the present embodiment. Therefore, the semiconductor processing tape of this embodiment has sufficient adhesive force, and the adherend after peeling off the semiconductor processing tape is difficult to produce the paste residue of the transfer adhesive layer, and the uneven absorbency and antistatic properties are excellent. . Accordingly, the tape for semiconductor processing of the present embodiment is suitable for the purpose of attaching to an adherend having uneven portions on the surface, and then peeling it off.

The tape for semiconductor processing of this embodiment can be suitably used as, for example, a tape for semiconductor processing that is attached during the back grinding step of a semiconductor wafer having uneven portions formed by bumps on the surface, and peeled off after the back grinding step use. In this case, the semiconductor wafer is fixed with sufficient adhesive force by the tape for semiconductor processing of this embodiment. Moreover, since the tape for semiconductor processing has sufficient unevenness absorbability, it is difficult to generate a gap between the tape for semiconductor processing attached to the semiconductor wafer and the periphery of the bump. Therefore, the water used in the back grinding step penetrates into the gap between the tape for semiconductor processing and the periphery of the bump, which can prevent contamination of the semiconductor wafer. In addition, since the tape for semiconductor processing of the present embodiment has sufficient antistatic performance, it is possible to suppress peeling charge when peeling off the tape for semiconductor processing attached to the semiconductor wafer after the back grinding step. Furthermore, it is preferable that after the back grinding step, it is difficult to produce paste residue around the bumps of the semiconductor wafer from which the tape for semiconductor processing is peeled off.

The tape for semiconductor processing of this embodiment can have a single-layer structure in which the adhesive layer is a cured product of the adhesive composition. In this case, only the step of forming one layer is performed, and the adhesive layer can be formed. Therefore, the tape for semiconductor processing of the present embodiment can be easily manufactured with fewer manufacturing steps compared to the case of forming a tape for semiconductor processing having a layer with unevenness absorption and a layer with adhesive force, for example. [Example]

Hereinafter, although the present invention will be explained in more detail with examples and comparative examples, the present invention is not limited to the following examples.

(Production Example 1) <Production of sheet-like base material 1 with antistatic layer> Mixed polypyrrole dispersion (PPY-12 manufactured by Marubi Oil Chemical Co., Ltd., solid content 8%) 9.4 parts by mass, polyester-based Binder (BI-12 manufactured by Marubi Oil Chemical Industry Co., Ltd., solid content 30%) 5.0 parts by mass, melamine-based crosslinking agent (CL-12 manufactured by Marubi Oil Chemical Industry Co., Ltd., solid content 25%) 2.6 Parts by mass, 0.05 parts by mass of polyoxyethylene lauryl ether, and 830.0 parts by mass of water to prepare an aqueous dispersion. Next, as the base body, on the sheet side of a 50 μm thick PET film (manufactured by Toyobo Co., Ltd., trade name: Ester (trademark) film E5100), the resin composition was heated and cured to have a thickness of 1.0 μm. , Coated with a gravure coater. Next, curing was performed at 130° C. for 1 minute to obtain a sheet-like base material 1. The electrical resistance of the base material 1 measured by a low resistivity meter (Loresta-AX manufactured by Mitsubishi Chemical Analytech Co., Ltd.) was 8×10 ⁵ Ω･cm.

(Comparative Production Example 1) <Production of sheet-like base material 2 with antistatic layer> Mixed polythiophene (Clevios (trademark) P solid content 1% manufactured by HC Starck) 93.0 parts by mass, polyester resin (VYLONAL manufactured by Toyobo Co., Ltd.) (Trademark) MD-1930, solid content 31%) 6.8 parts by mass, melamine-based crosslinking agent (CL-12 manufactured by Marubi Oil Chemical Industry Co., Ltd., solid content 25%) 2.4 parts by mass, polyoxyethylene lauryl ether 0.05 parts by mass and 900.0 parts by mass of water to prepare an aqueous dispersion. Next, as the base body, on the sheet side of a 50μm thick PET film (manufactured by Toyobo Co., Ltd., trade name: Ester (trademark) film E5100), the resin composition was heated and cured so that the film thickness became 1.0μm , Coated with a gravure coater. Next, curing was performed at 130° C. for 1 minute to obtain a sheet-like base material 2. The electrical resistance of the base material 2 measured by a low resistivity meter (Loresta-AX manufactured by Mitsubishi Chemical Analytech Co., Ltd.) was 4×10 ⁵ Ω･cm.

(Synthesis example 1) ＜Synthesis of Polyurethane (A-1)＞ In a reactor equipped with a thermometer, a stirrer, a dropping funnel, and a cooling tube with a drying tube, put the hydrogen additive of diphenylmethane diisocyanate (Desmodur W, manufactured by Sumika Covestro Urethane) 0.55 kg (2.1 mol), and Polypropylene glycol (ActcolD-2000; manufactured by Mitsui Chemicals, number average molecular weight 2000) 4.01kg (2.0mol) with a hydroxyl group with a hydroxyl value of 56mgKOH/g at the end, and dioctyltin ( NEOSTANN U-810, manufactured by Nitto Chemical Co., Ltd.) 0.8g.

Then, the reactor was heated to 60°C and reacted for 4 hours to obtain a polyurethane having isocyanate groups at both ends as a precursor of the polyurethane (A). Next, 23.22 g (0.2 mol) of 2-hydroxyethyl acrylate was added to the reactor, and the temperature was raised to 70° C. and reacted for 2 hours to obtain a polyurethane (A-1) with a mass average molecular weight of 67,000. 4.58kg.

The obtained polyurethane (A-1) was analyzed by infrared absorption spectroscopy (IR). As a result, no peak derived from an isocyanate group was observed. Based on this, it was confirmed that the polyurethane (A-1) was a polyurethane (a1) in which acryloxy groups were introduced at all ends.

(Synthesis example 2) ＜Synthesis of Polyurethane (A-2)＞ Except for replacing the hydrogen additives of diphenylmethane diisocyanate, using isophorone diisocyanate (Desmodur I, manufactured by Sumika Covestro Urethane) 2.1 mol, other than polyurethane (A-1) The synthesis method was carried out in the same way, and a polyurethane (A-2) with a mass average molecular weight of 66,000 was obtained.

The obtained polyurethane (A-2) was analyzed by infrared absorption spectroscopy (IR). As a result, no peak derived from an isocyanate group was observed. Based on this, it was confirmed that the polyurethane (A-2) was a polyurethane (a1) in which acryloxy groups were introduced at all ends.

(Cooperation examples 1~3, comparative cooperation examples 1~4) ＜Preparation of adhesive composition＞ The polyurethane (A) obtained by the above synthesis method, the (meth)acrylate monomer (B) shown in Table 1 and the chain transfer agent (C) and the photopolymerization initiator (D) ) Was blended with fatty acid ester (E) in the ratio described in Table 1, and mixed with a homogenizer at 25°C to obtain the adhesive composition c1~ of compounding examples 1 to 3 and comparative compounding examples 1 to 4 c7.

The following symbols described in Table 1 are the compounds shown below. 2EHA: 2-Ethylhexyl acrylate (manufactured by Toagosei Co., Ltd.) BUA: n-butyl acrylate (manufactured by Toagosei Co., Ltd.) ACMO: Acrylic morpholine (manufactured by Shinnakamura Chemical Industry Co., Ltd.) TMPTA: Trimethylolpropane triacrylate (manufactured by Toagosei Co., Ltd.)

PE1: Pentaerythritol 4 (3-mercaptobutyrate) (manufactured by Showa Denko Co., Ltd.) NR1: 1,3,5-ginseng(3-mercaptobutoxyethyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione (Showa Denko Co., Ltd. system) TPO (Omnirad TPO H): 2,4,6-trimethylbenzyldiphenylphosphine oxide (manufactured by IGM Resins B.V.) 184 (Omnirad 184): 1-hydroxycyclohexyl-phenyl ketone (manufactured by IGM Resins B.V.) EXEPARL IPM: Isopropyl myristate (manufactured by Kao Co., Ltd.) EXEPARL EH-S: 2-ethylhexyl stearate (manufactured by Kao Co., Ltd.)

(Example 1) Using an applicator on the surface of the base material 1 on the side of the antistatic layer, the adhesive composition c1 of the compounding example 1 in Table 1 was applied so that the cured thickness became 150 μm. Next, on the coated surface of the adhesive composition, as a separator, a 75μm thick polysiloxane-based ultra-light peeling PET film (manufactured by Toyobo Co., Ltd., product name: E7006) was laminated using a rubber roller. Then, through the partition, the adhesive composition was used with an ultraviolet irradiation device (manufactured by Eyegraphics Co., Ltd., UV irradiation device 3kW, high-pressure mercury lamp), with an irradiation distance of 25cm, a lamp moving speed of 1.0m/min, and an irradiation amount of 1000mJ/cm ^{Irradiate ultraviolet rays under the conditions of 2} to light-harden the adhesive composition. Thereby, the adhesive layer of the hardened|cured material of the adhesive composition laminated|stacked on the base material, and the tape for semiconductor processing of Example 1 with a separator were obtained.

(Example 2~Example 3 and Comparative Example 1~Comparative Example 6) Except that the base material and adhesive compositions c2 to c7 described in Table 2 were used, and the adhesive layer had the film thickness described in Table 2, the same method as in Example 1 was used to produce a tape for semiconductor processing. As a result, the tapes for semiconductor processing of Example 2-Example 3 and Comparative Example 1-Comparative Example 6 were obtained.

Next, the tapes for semiconductor processing of Example 1 to Example 3 and Comparative Example 1 to Comparative Example 4 were evaluated for the items shown below. The results are shown in Table 2. ＜Measurement of surface resistivity＞ Cut the tape for semiconductor processing into a size of 120mm in length and 120mm in width, and place it in an environment with a temperature of 23°C and a relative humidity of 50%RH for 3 hours and adjust the humidity. Then, the PET film was peeled off to expose the adhesive layer, and the surface of the adhesive layer side was measured using a high resistivity meter (manufactured by Mitsubishi Chemical Analytech Co., Ltd., Hiresta-UX) under the conditions of an applied voltage of 100V×60 seconds Resistivity. And use the following benchmarks for evaluation. The smaller the surface resistivity, the more difficult it is to generate peeling charge when peeling off the tape for semiconductor processing attached to a semiconductor wafer. It can be said that it is a tape for semiconductor processing with excellent antistatic performance.

Evaluation criteria ◎: Surface resistivity is less than 1×10 ¹¹ Ω/□ ○: Surface resistivity is 1×10 ¹¹ Ω/□ or more and less than 1×10 ¹² Ω/□ △: Surface resistivity is 1×10 ¹² Ω/□ or more and less than 1×10 ¹³ Ω/□ ×: The surface resistivity is 1×10 ¹³ Ω/□ or more

＜Peel strength (Peel strength)＞ Cut the tape for semiconductor processing into a size of 25 mm in length and 150 mm in width, and peel off the separator to expose the adhesive layer. Then, the exposed adhesive layer was laminated on the entire surface of the glass plate, and a rubber roller (diameter: 85 mm, width: 50 mm) with a mass of 2 kg (load 19.6 N) was performed one round trip to obtain a sample for measurement. The obtained measurement sample was left for 30 minutes in an environment with a temperature of 23° C. and a relative humidity of 50% RH. Then, in accordance with JIS K 6854-2, a 180° direction tensile test was performed at a peeling speed of 0.3 m/min., and the peeling strength (gf/25mm) to the glass plate was measured.

＜Concave-convex absorbency＞ Cut the tape for semiconductor processing into a size of 25 mm in length and 50 mm in width, and peel off the separator to expose the adhesive layer. Then, the exposed surface of the adhesive layer was paired with bumps of a wafer with bumps (manufactured by WALTS, WALTS-TEG FC150SCJY LF (PI), bump height: 75 μm, bump size: 90 μm in diameter) Always set. In addition, on the substrate of the tape for semiconductor processing, a rubber roller (diameter: 85mm, width: 50mm) with a mass of 2kg (load: 19.6N) was reciprocated 3 times at a speed of 10mm/sec, and the tape for semiconductor processing was bonded with the bumps. Block of wafers.

Observe the bumped wafer bonded with the semiconductor processing tape from the substrate side of the semiconductor processing tape with a digital optical microscope (with Hirox Co., Ltd., RH-2000), and observe the following standards , Evaluate the absorbency of bumps. "Benchmark" ○: There is no gap between the adhesive layer of the tape for semiconductor processing and the periphery of the bump of the bumped wafer. ×: There is a gap between the adhesive layer of the tape for semiconductor processing and the periphery of the bump of the bumped wafer.

＜Pollution caused by paste residue＞ Cut the tape for semiconductor processing into a size of 25 mm in length and 50 mm in width, and peel off the separator to expose the adhesive layer. Then, the exposed surface of the adhesive layer was paired with bumps of a wafer with bumps (WALTS Corporation, WALTS-TEG FC150SCJY LF (PI), bump height: 75 μm, bump size: 90 μm in diameter) Always set. Furthermore, on the substrate of the tape for semiconductor processing, a rubber roller (diameter: 85mm, width: 50mm) with a mass of 2 kg (load: 19.6N) was reciprocated 3 times at a speed of 10mm/sec, and the tape for semiconductor processing was bonded with the bumps. Block of wafers.

Place the bumped wafer bonded with the semiconductor processing tape at 23°C for 24 hours, and then peel off the semiconductor processing tape by hand at a speed of about 2m/min. In addition, the surface of the bumped wafer was observed with a digital optical microscope (manufactured by Hirox Co., Ltd., RH-2000), and the presence or absence of contamination due to residual paste was evaluated based on the following criteria. Still, the so-called "sticky residue" refers to the state where the adhesive layer itself remains attached to the surface of the wafer, and the surface of the wafer is sticky. "Benchmark" ○: There is no pollution caused by paste residue around the bumps. ×: There is contamination due to residual paste around the bumps.

＜Measurement of gel fraction＞ On a 75μm thick peeling PET film (manufactured by Dongshan Film Co., Ltd., brand name: Clean Sepa (trademark) HY-S10-2), use an applicator to apply an adhesive composition so that the cured thickness becomes 150μm Things. For Comparative Example 4, it was adjusted so that the thickness after curing became 30 μm. Next, the coating surface of the adhesive composition was coated with a polysiloxane-based ultra-light peeling PET film (manufactured by Toyobo Co., Ltd., product name: E7006) with a thickness of 75 μm.

Next, using an ultraviolet irradiation device (manufactured by Eyegraphics Co., Ltd., UV irradiation device 3kW, high-pressure mercury lamp), under the conditions of an irradiation distance of 25 cm, a lamp moving speed of 1.0 m/min, and an irradiation amount of 1000 mJ/cm ² , the PET film was peeled off ultra-lightly , Irradiating ultraviolet rays to harden the adhesive composition to obtain a hardened product (adhesive layer).

Next, the cured product (adhesive layer) was cut out to a size of approximately 1 g, and the PET film on both sides was peeled off and used as a sample for measurement, and its mass was measured. Next, the sample for measurement was immersed in 50 ml of toluene, and left to stand at room temperature for 72 hours. Then, the measurement sample was taken out from the toluene, dried at 80°C for 5 hours, and the mass was measured again. Furthermore, the gel fraction was measured according to the following formula. Gel fraction (%)=[A/B]×100 A: The mass of the measurement sample after immersing in toluene (the mass of toluene is not included) B: The mass of the measurement sample before immersion in toluene

As shown in Table 2, the tapes for semiconductor processing of Examples 1 to 3 show low surface resistivity and excellent antistatic properties. In addition, the peeling force (adhesive force) is high, and the unevenness absorbability is excellent. When peeling from the bumped wafer, no contamination due to paste residue is generated. In contrast, in Comparative Example 1 used for the base material 2 in which the antistatic layer does not contain a polypyrrole compound, the surface resistivity is high and the antistatic performance is deteriorated. As the adhesive composition, Comparative Examples 2, 3, and 6 where the chain transfer agent (C) was not used, the gel fraction of the adhesive layer could not be controlled in an appropriate range, and it became any one of peeling force, uneven absorbency, and paste residue It is the result of deterioration. Comparative Example 4 in which the thickness of the adhesive layer was thin did not obtain sufficient concavity and convexity absorbency. Compared with the adhesive composition c1 in Comparative Example 5, the chain transfer agent (C) was not used, but the adhesive composition c6 of the incremental photopolymerization initiator (D) was used. As a result, although a gel fraction equivalent to that of Example 1 was obtained, the uneven absorbency was insufficient and contamination due to paste residue also occurred. [Industrial availability]

According to the present invention, there is provided an adhesive tape for semiconductor processing that has sufficient unevenness absorption, antistatic performance, and adhesion, is difficult to produce paste residue, and can be manufactured in a few manufacturing steps. The tape for semiconductor processing can be preferably used for the purpose of protecting the surface of the semiconductor wafer and peeling off after the processing step in the semiconductor wafer processing step. Especially when performing a back grinding step of a semiconductor wafer on which bumps are formed on the surface equal to an object having uneven portions on the surface, it is suitable as a back grinding tape for surface protection.

Claims (8)

A tape for semiconductor processing, which has: a sheet-like substrate having a substrate body and an antistatic layer provided on at least one side of the substrate body, and The tape for semiconductor processing of the adhesive layer formed on the antistatic layer is characterized by The aforementioned antistatic layer contains a polypyrrole compound, The aforementioned adhesive layer is a cured product of the adhesive composition, The thickness of the aforementioned adhesive layer is 50~500μm, The aforementioned adhesive composition includes polyurethane (A), (meth)acrylate monomer (B), chain transfer agent (C), and photopolymerization initiator (D), The aforementioned polyurethane (A) contains polyurethane (a1), The aforementioned polyurethane (a1) has a skeleton including a polyoxyalkylene polyol-derived structure and a polyisocyanate-derived structure, and has a (meth)acryloyl group at a plurality of ends, The aforementioned (meth)acrylate monomer (B) contains monofunctional (meth)acrylate and polyfunctional (meth)acrylate. The tape for semiconductor processing according to claim 1, wherein the adhesive layer has a single-layer structure. The tape for semiconductor processing according to claim 1, wherein the chain transfer agent (C) is a polyfunctional mercaptan. The tape for semiconductor processing according to claim 1, wherein the gel fraction of the adhesive layer is 50 to 65% by mass. The tape for semiconductor processing of claim 1, wherein the surface resistivity of the adhesive layer is less than 1×10 ¹² Ω/□. The tape for semiconductor processing according to claim 1, wherein the (meth)acrylate monomer (B) contains 85 to 99 mol% of the monofunctional (meth)acrylate and the polyfunctional (meth)acrylic acid Ester 1~15 mole%. The tape for semiconductor processing of claim 1, wherein the aforementioned adhesive composition includes: The aforementioned polyurethane (A) 20-50% by mass, The aforementioned (meth)acrylate monomer (B) 35 to 79% by mass, The aforementioned chain transfer agent (C) 0.5-8% by mass, The aforementioned photopolymerization initiator (D) is 0.01 to 5% by mass. The tape for semiconductor processing according to any one of claims 1 to 7, wherein the adhesive composition system further contains fatty acid ester (E).