JP2012211254A - Adhesive and temporary adhesion method using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adhesive which has high adhesiveness but decomposes by the action of an acid to enable the expression of excellent peeling performance.SOLUTION: The adhesive comprises a polymer having units represented by formulae (1) and (2) as repeating units. (In the formulae, Rrepresents an optionally substituted alkyl group and the like; and Rrepresents an optionally substituted aryl group and the like). By including an acid generator, the polymer can decompose when irradiated with active energy rays.

Description

  The present invention relates to an adhesive containing a polymer having an acetal structure, an adhesion method using this adhesive (temporary adhesion method), and a method for processing an adherend (or a method for producing a processed adherend).

  The semiconductor manufacturing process includes a process of polishing (or grinding) the back surface of a wafer on which a pattern is formed (back grinding process) and a process of cutting a wafer thinned by polishing into chips (dicing process). In the back grinding process, in order to protect the wafer during polishing, it is usually composed of at least an adhesive layer (adhesive layer) and fixed to the wafer (wafer circuit surface, etc.) using a back grind tape as a protective sheet. After bonding and laminating the members and polishing the back surface of the wafer, the back grind tape is peeled from the wafer to obtain a thinned wafer.

  For this reason, the adhesive layer of the back grind tape is required to have sufficient adhesion enough to sufficiently protect (fix) the wafer even by polishing and ease of peeling after polishing. At present, such a pressure-sensitive adhesive layer is generally formed of a curable resin in order to use pressure-sensitive adhesiveness (adhesiveness) and peelability due to curing shrinkage. For example, Japanese Patent Laid-Open No. 2001-200215 (Patent Document 1) discloses a pressure-sensitive adhesive sheet that is used when processing a semiconductor wafer and is attached to the surface of the semiconductor wafer to hold and protect the semiconductor wafer. A substantially non-radiation-curable pressure-sensitive adhesive layer is formed on the other side of the substrate and cured with radiation to provide a radiation-curable pressure-sensitive adhesive layer with reduced adhesive strength (back surface for semiconductor wafer processing) Grind sheets or back grind tapes) are disclosed.

  Such a pressure-sensitive adhesive sheet exhibits releasability by utilizing the fact that the adhesive or the pressure-sensitive adhesive shrinks with curing. However, the method using such a curable resin cannot ensure sufficient peelability. Further, even after peeling, the adhesive layer may remain on the wafer, or such a residual adhesive layer may not be sufficiently separated from the wafer. Furthermore, after the adhesive layer is cured, in the peeling process between the wafer and the protective sheet (adhesive layer), the already thinned wafer may be cracked.

  In JP 2010-261000 A (Patent Document 2), an alternating copolymer of a benzaldehyde and an alkyl vinyl ether having an electron-withdrawing group is hydrolyzed with an acid to form a low molecular weight compound. It is described that it can be used as a functional polymer such as a resin. However, its usefulness as an adhesive is not described.

JP 2001-200215 A (Claims) JP 2010-261000 A (Claims, [Effects of the Invention])

  Accordingly, an object of the present invention is to provide an adhesive having a polymer having an acetal structure as an adhesive component and an adhesion method (temporary adhesion or temporary fixing method) using the adhesive.

  Another object of the present invention is to use an adhesive capable of being decomposed by the action of an acid and exhibiting excellent peelability despite having high adhesiveness (for example, thermal adhesiveness) and the adhesive. It is to provide a bonding method (temporary bonding or temporary fixing method).

  Still another object of the present invention is to provide an adhesive that can easily peel off adherends firmly bonded to each other, and a method for producing a processed adherend using this adhesive (or a method for processing an adherend). ) To provide.

  Another object of the present invention is to coat the surface of the workpiece with an adhesive or pressure-sensitive adhesive layer, and after processing the back surface of the workpiece, the separability of the workpiece polishing member from the adhesive or pressure-sensitive adhesive layer ( Temporary adhesive tape or protective tape that can improve or improve the releasability) and a manufacturing method (or processing method) for a member to be processed, for example, polishing a member to be polished (such as a wafer such as a semiconductor wafer) (such as back grinding) Then, it is providing the method of manufacturing the polished member to be polished.

  As a result of intensive studies to achieve the above-mentioned problems, the present inventors have found that a polymer having an acetal structure obtained by a reaction of a carbonyl compound (for example, an aldehyde compound) and a vinyl ether compound is sticky or adhesive (for example, , Hot melt adhesiveness or thermal adhesiveness) and can be suitably used as an adhesive, and such an adhesive is easily decomposed due to decomposition (low molecular weight) due to the action of an acid. It can be reduced to exhibit high peelability, and is useful as a temporary adhesive for temporarily fixing (fixing temporarily) the adherend and a protective sheet adhesive for a member to be polished such as a wafer to be used for polishing. As a result, the present invention was completed.

  That is, the adhesive of the present invention includes a polymer (or copolymer) having as a repeating unit units represented by the following formulas (1) and (2).

(Wherein R ¹ represents an alkyl group, an alkenyl group, a cycloalkyl group, an aryl group or an aralkyl group, and R ² represents a hydrogen atom, an alkyl group, an alkenyl group, a cycloalkyl group, an aryl group or a heterocyclic group. And at least one group selected from the alkyl group, alkenyl group, cycloalkyl group, aryl group, aralkyl group and heterocyclic group may have a substituent)
In Formula (1), R ¹ may be a linear or branched C _1-10 alkyl group, a linear or branched C _2-10 alkenyl group, or a C _5-10 cycloalkyl group. In addition, these alkyl group, alkenyl group and cycloalkyl group may have at least one substituent selected from a halogen atom and an alkoxy group. Further, R ¹ is a linear or branched C _1-6 alkyl which may have at least one substituent selected from a halogen atom and a linear or branched C _1-4 alkoxy group. It may be a group.

In the formula (2), R ² may be an aryl group optionally having at least one substituent selected from a halogen atom, an alkyl group, an alkoxy group, an alkoxyalkyl group, and a nitro group. Good. Further, R ² is a halogen atom, a linear or branched C _1-4 alkyl group, a linear or branched C _1-4 alkoxy group, or a C _1-4 alkoxy-C _1-4 alkyl group. It may be a C _6-12 aryl group which may have at least one selected substituent.

  Further, in the polymer, the unit represented by the formula (2) may be a unit represented by the following formula (2a).

(In the formula, R ³ represents a halogen atom, an alkyl group, an alkoxy group, or an alkoxyalkyl group, p represents 0 or an integer of 1 to 5, and when the coefficient p is 2 or more, the type of R ³ is They may be different, R ¹ is the same as above)
Further, the polymer may be an alternating copolymer having a repeating unit represented by the following formula (3).

(Wherein R ¹ and R ² are the same as above)
The polymer (or copolymer) is usually solid at room temperature and has hot-melt adhesiveness. The adhesive of the present invention may further contain an acid generator (thermal or photoacid generator). Such an adhesive forms a degradable adhesive (heat or photodegradable adhesive), generates an acid from the acid generator by irradiation with active energy rays (heat rays, light rays), and the polymer is formed by this acid. Can be disassembled. For this reason, the adhesive is processed after the surface of the workpiece is protected by covering the surface of the workpiece with a temporary fixing adhesive for peeling the adherends adhered to each other by irradiation of active energy rays. It is useful as an adhesive for separating the coating layer from the surface of the member (for example, an adhesive for forming a protective layer for protecting the surface of the wafer during polishing). Accordingly, the present invention provides a temporary adhesive tape (or temporary adhesive film) provided with an adhesive layer formed of the adhesive; a protective tape (a back grind tape or a back grind film) provided with an adhesive layer formed of the adhesive. Etc.).

  In the method for temporarily adhering an adherend according to the present invention, an adhering step of adhering the adherends to each other using the adhesive containing the acid generator, and active energy rays at least on the adhesion interface of the adhered adherends. Separates the adherend adhered to each other from the decomposition step (decomposition step of decomposing the polymer with the acid generated from the acid generator) by irradiating (or giving) (active light, heat ray, etc.) the polymer. Separating step (separating step for separating the adherend from the adhesive decomposed by the polymer).

  Further, the present invention uses an adhesive containing an acid generator to bond one surface of a member to be processed as an adherend to a fixed member that can move relative to the processing means. A process, a processing step of processing the other surface of the workpiece by the processing means, a decomposition step of decomposing the polymer by irradiating at least the adhesive interface with an active energy ray, and a processed member processed with the fixed member The manufacturing method of the processed member (or processing method of a to-be-processed member) including the isolation | separation process which isolate | separates these.

  In the present invention, at least one surface of a member to be processed as an adherend is coated with at least an adhesive (an adhesive containing an acid generator), and the other surface of the member to be processed is processed by a processing means. A processed member including a processing step, a decomposition step of decomposing a polymer by irradiating active energy rays at least on an adhesive interface, and a separation step of separating the processed workpiece and the coated adhesive layer A manufacturing method (a method for processing a workpiece or a method for protecting a workpiece) is also included.

  The present invention further includes a coating step of coating one surface (a protective surface such as a circuit surface) of a member to be polished (wafer or the like) as an adherend with at least an adhesive (an adhesive including an acid generator). A polishing step of polishing the other surface of the member to be polished (a surface opposite to the bonding surface) by a polishing means, and a decomposition step of decomposing the polymer by irradiating (or imparting) active energy rays to at least the bonding interface And a method for producing a polished member (such as a wafer) (a method for processing the member to be polished or a method for protecting the member to be polished), which includes a separation step of separating the polished member to be polished and the coated adhesive layer. Include.

  In these methods, in the bonding step, the adhesive may be heated and bonded by hot melt. For example, in the bonding step, the adhesive and the adherend may be bonded at 50 to 150 ° C. In addition, an adhesive containing a photoacid generator may be used, and in the decomposition step, the polymer may be decomposed with an acid generated from the acid generator by irradiating and heating an active energy ray. Further, since the adhesiveness is reduced due to the decomposition of the polymer, in the separation step, the adherend is slid with respect to the fixing member (or adhesive layer) (relative to the direction substantially parallel to the bonding surface). May be separated). Furthermore, the method may further include a cleaning step of cleaning the peeling surface (the adhesive surface with the adhesive) of the adherend after the separation step.

  In the present specification, the “adhesive” is not limited to a component that bonds two solid members, but a component that forms a coating layer or a protective layer that covers or protects the surface (such as a protective surface) of the solid member. Also means. “Tape” is used to mean including a film or sheet unless otherwise specified.

  The adhesive of the present invention contains a specific polymer having an acetal structure and has high adhesiveness (for example, thermal adhesiveness). Therefore, it is useful for adhesion of various adherends. Moreover, although it has high adhesiveness (for example, thermal adhesiveness), it can decompose | disassemble by the effect | action of an acid and can express the outstanding peelability. Therefore, the adherends firmly bonded to each other can be easily peeled off, which is suitable as a temporary fixing adhesive for a workpiece to be processed that requires both adhesiveness and peelability. Moreover, after covering and protecting a workpiece, it is useful as a temporary adhesive tape or a protective tape for separating or peeling the processed member. For example, adhesion of a protective tape (back grind tape, etc.) Suitable as an agent. Furthermore, the releasability (peelability) of the processed workpiece with respect to the adhesive layer or the protective layer can be improved or improved by utilizing the releasability due to the decomposition of the polymer. Therefore, the present invention provides a method for manufacturing a processed member (for example, a polished member such as a polished wafer after back grinding), or a processed member (for example, a polished member such as a wafer to be subjected to polishing). It is also useful as a method for processing a member.

  The adhesive of the present invention contains a polymer having a unit represented by the formulas (1) and (2) as a repeating unit, and this polymer has a specific acetal structure (one oxygen atom of the acetal). (Ether bond) in the main chain and the other oxygen atom (ether bond) in the side chain).

In the formula (1), R ¹ represents an alkyl group, an alkenyl group, a cycloalkyl group, an aryl group or an aralkyl group. Examples of the alkyl group represented by R ¹ include linear groups such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, s-butyl, t-butyl, pentyl, isopentyl, hexyl, octyl and 2-ethylhexyl groups. Or a branched _C1-10 alkyl group etc. can be illustrated. Preferred alkyl groups are, for example, linear or branched C _1-8 alkyl groups, in particular linear or branched C _1-6 alkyl groups.

Examples of the alkenyl group include linear or branched C _2-10 alkenyl groups such as 2-propenyl group (allyl group) and 2-butenyl group. Preferred alkenyl groups are, for example, linear or branched C _2-6 alkenyl groups, in particular linear or branched C _2-4 alkenyl groups.

Examples of the cycloalkyl group include C _3-12 cycloalkyl groups such as cyclopentyl, cyclohexyl, cyclooctyl, and cyclodecanyl groups. The cycloalkyl group includes, for example, an aliphatic C _7-12 bridged cyclic hydrocarbon group (such as a bicyclic or tricyclic hydrocarbon group) such as a bicyclooctyl group or a tricyclodecanyl group. Preferred cycloalkyl groups are C _5-10 cycloalkyl groups.

Examples of the aryl group include C _6-12 aryl groups such as a phenyl group and a naphthyl group. A preferred aryl group is a C _6-10 aryl group. Examples of the aralkyl group include C _6-12 aryl-C _1-4 alkyl groups such as benzyl group and phenethyl group.

Preferred R ¹ is a linear or branched alkyl group (for example, a C _1-10 alkyl group, preferably a C _1-8 alkyl group, more preferably a C _1-6 alkyl group), a linear or branched chain Alkenyl groups (eg, C _2-10 alkenyl groups, preferably C _2-6 alkenyl groups, more preferably C _2-4 alkenyl groups), or cycloalkyl groups (eg, C _5-10 cycloalkyl groups, preferably C _6-10 cycloalkyl group), particularly an alkyl group (eg, a linear or branched C _1-6 alkyl group).

R ¹ may have a substituent. Examples of the substituent include a halogen atom (a fluorine atom, a chlorine atom, a bromine atom, an iodine atom), an alkoxy group (a linear or branched C _1-6 alkoxy group such as a methoxy, ethoxy, or butoxy group), Carbonyl group, carboxyl group, alkoxycarbonyl group (linear or branched C _1-6 alkoxy-carbonyl group such as methoxycarbonyl group or ethoxycarbonyl group), cycloalkyloxycarbonyl group (C such as cyclohexyloxycarbonyl group) _5-10 cycloalkyloxy-carbonyl groups, etc.), aryloxycarbonyl groups (C _6-10 aryloxy-carbonyl groups such as phenyloxycarbonyl groups), aralkyloxycarbonyl groups (C _6-10 such as benzyloxycarbonyl groups). aryl _{-C 1-4} A Kiruokishi - carbonyl group), an acyl group (formyl group, acetyl group, a linear or branched C _1-6 alkyl, such as propionyl group - carbonyl group, (meth) linear or branched, such as acryloyl groups C _2-6 alkenyl-carbonyl group, (meth) acryloyloxy (mono or poly) C _2-4 alkoxy group, C _5-10 cycloalkyl-carbonyl group such as cyclohexylcarbonyl group, C ₆ such as benzoyl group, naphthoyl group _-10 aryl-carbonyl group), sulfonylalkyl group, alkylsulfonylalkyl group, formyl group, carbonyl group (ketone group), cyano group, nitro group and the like. These substituents may be electron withdrawing groups in relation to R ¹ . The number of these substituents is often about 0 to 3, and when a plurality of substituents are substituted, the same or different substituents may be substituted.

Preferred substituents are halogen atoms (such as chlorine atoms) and alkoxy groups (such as linear or branched C _1-4 alkoxy groups such as methoxy, ethoxy, and butoxy groups). Examples of the alkyl group having such a substituent include a haloalkyl group (haloC _1-6 alkyl group such as chloromethyl, chloroethyl, bromoethyl, chloropropyl, 2,2,2-trichloroethyltrifluoroethyl group, etc.) And alkoxyalkyl groups [for example, C _1-4 alkoxy-C _1-4 alkyl groups such as 2-methoxyethyl, 2-ethoxyethyl and 4-methoxybutyl groups] and the like. In addition, a group containing a polymerizable group, for example, an alkenylcarbonyloxyalkyl group [C _2-6 alkenyl-carbonyloxy-C _2-6 alkyl group such as (meth) acryloyloxyethyl group], alkenylcarbonyloxy (mono or Poly) alkoxy group [C _2-6 alkenyl-carbonyloxy- (mono or poly) C _2-4 alkoxy-C _2-6 alkyl group such as (meth) acryloyloxyethoxy group, (meth) acryloyloxydiethoxy group, etc. ] Is also preferable. When such a polymerizable group is used, the strength of the adhesive, the adhesive strength, and the like can be adjusted by combining with a high energy beam or a polymerization initiator.

In the formula (2), R ² represents a hydrogen atom, an alkyl group, an alkenyl group, a cycloalkyl group, an aryl group or a heterocyclic group. Alkyl group, an alkenyl group represented by R ^2, cycloalkyl group and aryl group, like a linear or branched alkyl group as R ^1, linear or branched alkenyl group, and cycloalkyl groups An aryl group can be illustrated. Preferred R ^{2 is} also a linear or branched C _1-10 alkyl group (for example, a linear or branched C _1-8 alkyl group, particularly a linear or branched group, in the same manner as the group described for R ^1. A linear C _1-6 alkyl group), a linear or branched C _2-10 alkenyl group (eg, a linear or branched C _2-6 alkenyl group, particularly a linear or branched C _{2). -4} alkenyl group), C _5-10 cycloalkyl group (for example, C _6-10 cycloalkyl group), C _6-12 aryl group (for example, C _6-10 aryl group). As the heterocyclic group, a heterocyclic group containing at least one hetero atom selected from a nitrogen atom, an oxygen atom and a sulfur atom as a constituent atom of the ring, for example, a 5- or 6-membered heterocyclic ring such as pyridyl, furyl, thiophenyl group Examples thereof include condensed heterocyclic groups containing these heterocyclic groups.

Preferable R ² is an aromatic homocyclic or heterocyclic group, for example, an aryl group (C _6-12 aryl group such as phenyl group, naphthyl group, etc., particularly C _6-10 aryl group).

The alkyl group, alkenyl group, cycloalkyl group, aryl group or heterocyclic group represented by R ² may have a substituent. Examples of the substituent include linear or branched chain such as halogen atom (fluorine atom, chlorine atom, bromine atom, iodine atom), alkyl group (methyl, ethyl, propyl, isopropyl, butyl, isobutyl, t-butyl group). -Like C _1-6 alkyl group), alkoxy groups (such as linear or branched C _1-6 alkoxy groups such as methoxy, ethoxy, propoxy, isopropoxy, butoxy, t-butoxy groups), alkoxyalkyl groups ( C _1-6 alkoxy-C _1-6 alkyl group such as methoxymethyl group, ethoxymethyl, ethoxyethyl group, ethoxybutyl group, etc.), carboxyl group, alkoxycarbonyl group (linear chain such as methoxycarbonyl group, ethoxycarbonyl group, etc.) or branched-chain _{C 1-6} alkoxy - carbonyl group), a cycloalkyl Oki Carbonyl group (C _5-10 cycloalkyloxy such as cyclohexyloxy group - carbonyl group), an aryloxycarbonyl group (C _6-10 aryloxy such as phenyloxy carbonyl group - carbonyl group), an aralkyloxycarbonyl group ( Linear or branched C _1-6 alkyl such as C _6-10 aryl-C _1-4 alkyloxy-carbonyl group such as benzyloxycarbonyl group, acyl group (formyl group, acetyl group, propionyl group, etc.) C _5-10 cycloalkyl-carbonyl group such as carbonyl group and cyclohexylcarbonyl group, C _6-10 aryl-carbonyl group such as benzoyl group and naphthoyl group), nitro group, cyano group and the like.

The type of these substituents and the number of substituents can be selected according to the type of R ² , and the number of substituents is often about 0 to 5. When a plurality of substituents are substituted, the same or different substituents may be substituted. For example, examples of the alkyl group having a substituent include an alkyl group having an aryl group (for example, a C _6-10 aryl-C _1-4 alkyl group such as a benzyl group). Examples of the group include an alkenyl group having an aryl group (for example, a C _6-10 aryl-C _2-4 alkenyl group such as a 2-phenylvinyl group).

Preferred R ² is an aryl group which may have a substituent. Particularly preferred polymer has a unit represented by the formula (2a). That is, a polymer in which R ² is a phenyl group which may have a substituent R ³ is preferable.

In the formula (2a), preferred substituents are a halogen atom (such as a chlorine atom), an alkyl group (such as a linear or branched C _1-4 alkyl group), and an alkoxy group (such as a linear or branched C _{1). -4} alkoxy group, etc.), alkoxyalkyl groups (C _1-4 alkoxy-C _1-4 alkyl group etc.), nitro groups and the like.

When R ² is an aryl group, examples of the aryl group having a representative substituent include a haloaryl group (2-, 3- or 4-chlorophenyl group, 2,3-, 2,4-, 2,5 -, Halo C _6-10 aryl group such as 3,5-dichlorophenyl group), alkyl aryl group (C _1-4 alkyl-C _6-10 aryl group such as tolyl group, xylyl group, 4-ethylphenyl group, etc.) ), An alkoxyaryl group (linear, branched C _1-4 alkoxy-C _6-10 aryl such as 2-, 3- or 4-methoxyphenyl group, 4-ethoxysiphenyl group, 4-butoxyphenyl group) Group), alkoxyalkylaryl group (methoxymethylphenyl group, ethoxymethylphenyl group, methoxybutylphenyl group, etc., linear or branched C _1-4 alcohol) Carboxymethyl etc. _{-C 1-4} alkyl _{-C 6-10} aryl group), a nitro _{C 6-10} aryl group such as nitroaryl group (2-, 3- or 4-nitrophenyl group), and others.

  In the formula (2a), p is 0 or an integer of 1 to 5, preferably 0 or an integer of 1 to 3 (for example, 0, 1 or 2).

When a plurality of substituents R ² is substituted, the type of the plurality of substituents may be the same or different. For example, in the formula (2a), when the coefficient p is 2 or more, the types of R ³ may be the same or different. For example, a plurality of halogen atoms, a plurality of alkyl groups, or a plurality of alkoxy groups may be a phenyl group. It may be substituted, and both a halogen atom and an alkyl group, and both an alkyl group and an alkoxy group may be substituted with a phenyl group.

[Polymer structure and properties]
The polymer (copolymer) of the present invention may have a unit represented by the above formulas (1) and (2) as a repeating unit, and may be a random polymer, a block polymer, or an alternating copolymer. It may be. In the polymer (copolymer) of the present invention, the ratio (molar ratio) between the unit represented by the formula (1) and the unit represented by the formula (2) is, for example, the former / the latter = 30 / It may be about 70 to 70/30, preferably 40/60 to 60/40, and more preferably about 45/55 to 55/45. A particularly preferable polymer (copolymer) is an alternating copolymer represented by the formula (3). This alternating copolymer may be a completely alternating copolymer, for example, a partially irregular unit (or repeating unit) in which the ratio (molar ratio) is about the former / the latter = 45/55 to 55/45. ). The alternating copolymer seems to generate a low molecular weight compound corresponding to each unit without leaving a relatively high molecular weight oligomer or the like with decomposition by heat or light. For this reason, the alternating copolymer has the advantage that the adhesiveness can be greatly reduced with decomposition, and the produced low molecular weight compound can be easily removed by washing.

The number average molecular weight Mn of the polymer is, for example, 0.1 × 10 ⁴ to 50 × 10 ⁴ , preferably 0.5 × 10 ^{4 to} 25 × 10 ⁴ , and more preferably 1 × 10 ⁴ to 10 × 10 ^4. (For example, about 1 × 10 ^{4 to} 5 × 10 ⁴ ). The molecular weight distribution (Mw / Mn) of the polymer is, for example, about 1 to 3, preferably about 1.1 to 2.5, more preferably about 1.2 to 2 (for example, 1.3 to 1.5). May be. Mw represents a weight average molecular weight, and Mn represents a number average molecular weight. The molecular weight and molecular weight distribution can be measured, for example, as a value in terms of polystyrene using GPC (gel permeation chromatography).

  The polymer is usually solid at normal temperature (for example, 15 to 25 ° C.). Further, the polymer has adhesiveness (or tackiness), particularly hot melt adhesiveness (thermal adhesiveness). Therefore, the melting temperature [hot melt adhesion temperature (temperature capable of hot melt adhesion)] of the polymer may be 30 to 150 ° C, preferably 50 to 140 ° C, and more preferably about 80 to 120 ° C.

  The glass transition temperature of the polymer is, for example, −20 ° C. to 100 ° C., preferably 0 to 80 ° C., more preferably about 20 to 60 ° C., as measured by a differential scanning calorimeter.

  In addition, the viscosity (or melting temperature) of the polymer is, for example, 0.01 to 100 Pa · s, preferably 0.03 to 10 Pa · s, more preferably 0.05 to 5 Pa · s (for example, at 100 ° C.) 0.07 to 2.5 Pa · s). The viscosity can be measured with a rheometer, for example.

  The polymer (copolymer) is usually soluble in a general-purpose solvent. Therefore, it is also suitable for coating applications. Examples of such solvents include aromatic solvents (for example, aromatic hydrocarbons such as toluene and xylene), halogen solvents (for example, haloalkanes such as dichloromethane and chloroform), alcohol solvents (for example, ethanol). , Alkanols such as isopropanol, alkoxyalkanols such as 3-methoxybutanol, etc.), ester solvents (eg, acetate esters such as methyl acetate, ethyl acetate, butyl acetate, 3-methoxybutyl acetate), ketone solvents ( For example, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, etc.), ether solvents (eg, chain ethers such as diethyl ether, diisopropyl ether, dibutyl ether; cyclic ethers such as dioxane, tetrahydrofuran, etc.) Tel), glycol ethers (eg, ethylene glycol monomethyl ether (methyl cellosolve), ethyl cellosolve, cellosolves such as butyl cellosolve; propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol mono Ethyl ether, diethylene glycol monobutyl ether, diethylene glycol dimethyl ether, etc.), glycol ether esters (eg, ethylene glycol monomethyl ether acetate, propylene glycol monomethyl ether acetate, etc.), nitrile solvents (eg, acetonitrile, benzonitrile, etc.), nitro solvents (eg, For example, Etc. Robenzen), amides (N, N-dimethylformamide, N, N- dimethylacetamide, etc.), nitriles (acetonitrile, benzonitrile), and mixtures of these solvents.

  Since the polymer (copolymer) of the present invention has a property of being easily decomposed by an acid, it can be used as an acid-responsive material (or acid-sensitive resin).

[Method for producing polymer having acetal structure]
The polymer (or copolymer) of the present invention can be obtained by reacting (cationic polymerization) a vinyl ether compound represented by the following formula (1b) and an aldehyde compound represented by the following formula (2b). it can.

(Wherein R ¹ and R ² are the same as above)
As the vinyl ether compound represented by the formula (1b), a compound (monomer) corresponding to the formula (1) can be used. Typical vinyl ether compounds include, for example, alkyl vinyl ethers (methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether, isopropyl vinyl ether, butyl vinyl ether, isobutyl vinyl ether, s-butyl vinyl ether, t-butyl vinyl ether, pentyl vinyl ether, hexyl vinyl ether, octyl vinyl ether. , 2-ethylhexyl vinyl ether, decyl vinyl ether, e.g., a straight chain or branched chain C _1-16 alkyl vinyl ethers such as dodecyl vinyl ether); alkenyl vinyl ethers (such as allyl vinyl ether); C, such as cycloalkyl vinyl ether (cyclohexyl vinyl _{5- 10} cycloalkyl - vinyl ethers, preferably _{C 5-8} Black alkyl - ether); aryl vinyl ethers (such as phenyl vinyl ether); aralkyl vinyl ethers (e.g., benzyl vinyl, _{C 6-10} aryl _{-C 1-4} alkyl, such as phenethyl vinyl ether - ether), and others. Representative vinyl ether compounds having a substituent include, for example, haloalkyl vinyl ethers (2-chloroethyl vinyl ether, 2-bromoethyl vinyl ether, 3-chloropropyl vinyl ether, 3-bromopropyl vinyl ether, 2,2,2-trifluoro Halo C _1-10 alkyl-vinyl ethers such as ethyl vinyl ether, preferably halo C _1-6 alkyl-vinyl ethers; C _2-10 alkenyl-vinyl ethers (1-propenyl vinyl ether, 2-propenyl vinyl ether, 1-butenyl vinyl ether, etc. ); (Meth) acryloyloxyalkyl-vinyl ethers [eg (meth) acryloyloxy C _2-6 alkyl-bi, such as 2- (meth) acryloyloxy) ethyl-vinyl ether Nyl ethers, preferably (meth) acryloyloxy _C2-4 alkyl-vinyl ethers, etc.]; (meth) acryloyloxy (poly) alkoxyalkyl-vinyl ethers [e.g. 2- (2- (meth) acryloyloxyethoxy) ethyl-vinyl ether (Meth) acryloyloxy- (poly) C _2-6 alkoxy-C _2-6 alkyl-vinyl ether, preferably (meth) acryloyloxy-mono to hexa C _2-4 alkoxy-C _2-4 alkyl-vinyl ether, More preferably, (meth) acryloyloxymono to tetra C _2-3 alkoxy C _2-3 alkyl-vinyl ether etc.]; cyanoalkyl vinyl ethers (such as 2-cyanoethyl vinyl ether); alkoxycarbonylalkyl vinyl ethers Tellurium ((2-methoxycarbonylethyl) vinyl ether, (2-ethoxycarbonylethyl) vinyl ether, etc.); aryloxycarbonylalkyl vinyl ethers ((2-phenoxycarbonylethyl) vinyl ether, etc.); aralkyloxycarbonylalkyl vinyl ethers ((2 -Benzyloxycarbonylethyl) vinyl ether and the like); oxoalkyl vinyl ethers (such as (3-oxobutyl) vinyl ether) and the like. These vinyl ether compounds can be used alone or in combination of two or more.

As the aldehyde compound represented by the formula (2b), a compound (monomer) corresponding to the formula (2) can be used. Typical aldehyde compounds include, for example, alkanals (linear or branched C _1-10 alkanals such as formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, isobutyraldehyde, valeryl aldehyde, isovaleryl aldehyde). and preferably _{C 2-8} alkanals); alkenyl aldehydes (e.g., a straight chain or branched chain _{C 3-10} alkenyl aldehydes such acrolein); cycloalkyl aldehydes _{(C 5-10} cycloalkyl such as cyclohexyl aldehyde aldehyde, etc.); aryl aldehydes (benzaldehyde, such as C _6-10 aryl aldehydes such as naphthyl aldehyde); aromatic or non-aromatic heterocyclic aldehydes (furfural, thiophene aldehyde, Nico 5- or 6-membered heterocyclic aldehyde containing at least one heteroatom selected from nitrogen, oxygen and sulfur atoms such as aldehyde, or condensed heterocyclic aldehyde in which the 5- or 6-membered heterocyclic ring is condensed with a benzene ring And the like.

Representative aldehyde compounds having a substituent include alkyl aldehydes having an aryl group (such as phenylacetaldehyde and naphthylacetaldehyde); alkenyl aldehydes having an aryl group (such as cinnamaldehyde); aryl aldehydes having a halogen atom (4 -Halo C _6-10 aryl-aldehydes such as chlorobenzaldehyde, 3-chlorobenzaldehyde, 2-chlorobenzaldehyde, 2,4-dichlorobenzaldehyde, 3,5-dichlorobenzaldehyde; arylaldehydes having an alkyl group (tolylaldehyde) (2-, 3- or 4-methylbenzaldehyde), 4-ethylbenzaldehyde, 4-t-butylbenzaldehyde, xylylaldehyde (2,3-, 2,4-, 2,5- or Is a linear or branched C _1-4 alkyl-C _6-10 aryl-aldehyde, such as 2,6-dimethylbenzaldehyde); aryl aldehydes having an alkoxy group (4-methoxybenzhydraldehyde (anisaldehyde) ), Linear or branched C _1-4 alkoxy-C _6-10 aryl-aldehyde, such as 3-methoxybenzfludehydride, 4-ethoxycybenzaldehyde, 4-butoxybenzhydride, etc.); alkoxyalkyl Aryl aldehydes having a group (such as linear or branched C _1-4 alkoxy-C _1-4 alkyl-C _6-10 aryl-aldehyde such as methoxymethyl benzhydride and ethoxymethyl benzhydride); nitro Aryl aldehydes having a group (nitrobenzhydride (4--3 And nitro C _6-10 aryl-aldehyde) and the like. These aldehyde compounds can be used alone or in combination of two or more.

  Even if a vinyl ether compound having no electron-withdrawing group (such as the alkyl vinyl ethers) is reacted with a aldehyde compound having a substituent (such as a aldehyde having a substituent described above) (cation polymerization), The polymerizability ratio can be increased, and the alternating copolymer can also be obtained.

  The ratio (molar ratio) between the vinyl ether compound represented by the formula (1b) and the aldehyde compound represented by the formula (2b) is, for example, the former / the latter = 40/60 to 60/40, preferably 45 / 55 to 55/45, more preferably about 48/52 to 52/48.

  The polymer (copolymer) includes a vinyl ether compound represented by the formula (1b) and an aldehyde compound represented by the formula (2b) in the presence of an added base and an initiator containing a Lewis acid. Can be obtained by reaction (cation polymerization).

As the added base, Lewis base (weak Lewis base) such as esters and ethers can be used. Examples of the esters include alkane carboxylic acid esters (C _1-6 alkane-carboxylic acid such as methyl formate, ethyl formate, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, phenyl acetate, methyl propionate, ethyl propionate). C _1-4 alkyl ester), arene carboxylic acid ester (C _6-10 arene-carboxylic acid C _1-4 alkyl ester such as methyl benzoate and ethyl benzoate), haloalkane carboxylic acid ester (methyl chloroformate, ethyl chloroformate) Halo C _1-6 alkane-carboxylic acid C _1-4 alkyl ester such as methyl chloroacetate, ethyl chloroacetate, ethyl trichloroacetate and ethyl trifluoroacetate). Of these esters, alkane carboxylic acid esters and haloalkane carboxylic acid esters are preferred.

  Examples of the ethers include chain ethers such as diethyl ether, dipropyl ether, dibutyl ether, diphenyl ether, and dibenzyl ether; and cyclic ethers such as 1,4-dioxane and tetrahydrofuran. Of these ethers, cyclic ethers are preferred.

  The usage-amount of an addition base is 0.001-100 mol normally with respect to 1 mol of aldehyde compounds, Preferably it is 0.1-25 mol, More preferably, it is about 1-5 mol.

Examples of the Lewis acid include Group 4 elements (such as titanium, zirconium, hafnium), Group 8 elements (such as iron), Group 12 elements (such as zinc), Group 13 elements (such as aluminum, gallium, and indium), 14 A compound containing a group element (silicon, germanium, tin, etc.) or a group 15 element (bismuth, etc.) can be used. The compound that forms a Lewis acid may be a halide (chloride, fluoride, etc.), sulfate or the like. Preferred Lewis acids are halides (eg, chlorides) such as iron, aluminum, gallium, and tin. Typical Lewis acids include, for example, FeCl ₃ , SnCl ₄ , GaCl _{3 and the} like.

  The amount of Lewis acid used is, for example, about 0.0001 to 0.1 mol, preferably 0.0005 to 0.05 mol, and more preferably about 0.001 to 0.02 mol, relative to 1 mol of the aldehyde compound. is there.

  Such Lewis acids may be combined with a proton acid or cation source to form an initiator system. Examples of the protonic acid include inorganic acids such as hydrogen chloride; organic carboxylic acids such as acetic acid, trichloroacetic acid, and trifluoroacetic acid; haloalkanesulfonic acids such as methanesulfonic acid, ethanesulfonic acid, and trifluoromethanesulfonic acid, and benzenesulfonic acid. And organic sulfonic acids such as aryl sulfonic acids such as p-toluenesulfonic acid and naphthalenesulfonic acid. Of these protonic acids, organic sulfonic acids (such as haloalkanesulfonic acids such as ethanesulfonic acid) are preferred. Examples of the cation source include halogenated trimethylsilyl (such as trimethylsilyl iodide).

  The amount of the protonic acid or cation source used is, for example, 0.0001 to 0.1 mol, preferably 0.0005 to 0.05 mol, more preferably 0.001 to 0.02 mol, relative to 1 mol of the aldehyde compound. Degree.

  When such an initiator is used, the cationic polymerization proceeds in a living manner, and a polymer (copolymer) having a narrow molecular weight distribution is obtained.

  The reaction is carried out in the presence or absence of a solvent. Examples of the solvent include solvents that are inert to the reaction, such as aliphatic hydrocarbons (pentane, hexane, heptane, octane, etc.), alicyclic hydrocarbons (cyclohexane). Pentane, cyclohexane, etc.), aromatic hydrocarbons (benzene, toluene, xylene, etc.), halogenated hydrocarbons (eg, dichloromethane, chloroform, etc.), and the like. These mixed solvents are mentioned.

  If necessary, a proton trapping agent (for example, 2,6-di-t-butylpyridine (DTBP)) may be present in the reaction system in order to suppress the formation of by-products. The amount of proton trapping agent used is usually the same as the amount of proton acid or cation source used.

  The reaction can be performed, for example, at a temperature of about -120 ° C to 50 ° C, preferably about -100 ° C to 20 ° C (eg, -100 ° C to -20 ° C). The reaction may be performed under an atmosphere of inert gas (such as helium, nitrogen, argon) or under circulation. The reaction may be performed under normal pressure or under pressure. After completion of the reaction, for example, it can be quenched with an ammoniacal methanol solution and purified by a conventional method such as filtration, concentration, dissolution or elution, and precipitation to obtain a polymer.

[Adhesive and its use]
Since the adhesive of the present invention has high adhesiveness, it only needs to contain the polymer (copolymer), and may further contain an acid generator. When an acid generator is contained, adhesiveness (for example, hot melt adhesiveness) and acid decomposability can be imparted, and a heat decomposable adhesive or a photodegradable adhesive can be formed.

  Examples of the acid generator include thermal acid generators that generate an acid by heat [for example, sulfonic acid-based thermal acid generators (for example, arene sulfonic acid esters (for example, benzoin tosylate, nitrobenzyl tosylate, etc.) Esters), carboxylic acid-based thermal acid generators (for example, fatty acids (for example, citric acid, acetic acid, maleic acid, etc.) or salts thereof, aromatic carboxylic acids (for example, benzoic acid, phthalic acid, etc.) or salts thereof), Phosphoric acid-based thermal acid generators (for example, phosphoric acid, organic phosphate esters, etc.)], photoacid generators, and the like. The acid generators may be used alone or in combination of two or more.

  In addition, when combining a hot-melt-adhesive polymer and a thermal acid generator, the thermal-acid generator which does not generate | occur | produce an acid at hot-melt adhesion temperature is used suitably. A preferred acid generator is a photoacid generator. When a photoacid generator is used, even if the polymer has hot melt adhesiveness, the polymer can be efficiently decomposed by light irradiation after adhering the adherend.

The photoacid generator may be an acid generator that generates an acid by heat, but typically the acid is generated by irradiation with actinic rays (for example, visible light, ultraviolet rays, electron beams, X-rays, etc.). It is a generated acid generator. Representative active rays include visible rays, ultraviolet rays and the like. Typical photoacid generators include, for example, quinonediazide compounds, onium salts (for example, sulfonium salts, phosphonium salts, diazonium salts, iodonium salts, selenium salts), phenols, sulfonic acids or esters thereof, carboxylic acids or esters thereof. Etc. can be exemplified. Examples of the counter ion of the onium salt include borate (eg, BF ₄ ⁻ , B (C ₆ F ₅ ) ₄ ^—, etc.), phosphate (eg, PF ₆ ^— etc.), sulfonate (eg, CF ₃ SO _3). ^- etc.), antimonate (e.g., SbF ₆ ^-, etc.), and the anions such.

  Specific photoacid generators include, for example, quinonediazide compounds (for example, naphthoquinonediazide compounds), sulfonium salts [for example, alkylsulfonium salts (for example, trialkylsulfonium salts), arylsulfonium salts (for example, diarylsulfonium salts) , Triarylsulfonium salts, etc.], phosphonium salts [eg, arylphosphonium salts (eg, triarylphosphonium salts), etc.], diazonium salts (eg, aryldiazonium salts), iodonium salts [eg, aryliodonium salts (eg, Diaryliodonium salts)], selenium salts [eg, aryl selenium salts (eg, triaryl selenium salts)], phenols (eg, phenol, resorcinol, pyrogallo) , 1,2-dihydroxynaphthalene, 1,3-dihydroxynaphthalene, etc.), sulfonic acids (for example, alkane sulfonic acids such as methane sulfonic acid, ethane sulfonic acid, propane sulfonic acid, butane sulfonic acid; benzene sulfonic acid, naphthalene sulfonic acid) Arene sulfonic acid such as camphor sulfonic acid) or an ester thereof (for example, arene sulfonic acid ester). The photoacid generators may be used alone or in combination of two or more.

  The ratio of the acid generator is, for example, 0.01 to 20 parts by weight, preferably 0.1 to 15 parts by weight, more preferably 0.5 to 10 parts by weight with respect to 100 parts by weight of the polymer (copolymer). It may be about a part.

  Adhesives or adhesive compositions can be prepared by using conventional additives such as stabilizers (antioxidants, heat stabilizers, etc.), colorants (pigments, etc.), thickeners, antifoaming agents, interfaces as required. Activators, antistatic agents, flame retardants, fillers, sensitizers and the like may be included. The adhesive or adhesive composition may also contain a polymerization initiator (heat or photopolymerization initiator) or a polymerization initiator system. These additives may be used alone or in combination of two or more.

  Further, the adhesive or the adhesive composition may be a solventless adhesive that does not contain a solvent, or may be a solvent adhesive that contains a solvent, depending on the application. As a solvent, the solvent of the polymer (copolymer) of the said illustration is mentioned. The amount of the solvent used is, for example, a range where the adhesive can be applied, for example, a polymer content or a solid content of 1 to 70% by weight, preferably 5 to 50% by weight, more preferably 10 to 30% by weight. It may be a degree.

  The adhesive of the present invention can be used in the form of a solid (powder, granule, pellet, rod, sheet, etc.) or in a liquid form, and the sheet adhesive can usually be laminated on an adherend. It is. The thickness of the sheet-like adhesive may be, for example, 1 to 300 μm (for example, 2 to 200 μm), preferably 5 to 100 μm, and more preferably about 10 to 80 μm.

  The adhesive (sheet adhesive or the like) of the present invention can be used in the form of a laminated sheet laminated on a base sheet (or base film), if necessary. The material of the base sheet is not particularly limited, and plastic (for example, olefin resin (polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, etc.), polyester resin (polyethylene terephthalate, Butylene terephthalate, polyethylene naphthalate, etc.), polyamide resin (nylon 6, nylon 66, nylon 12, etc.), styrene resin (polystyrene, styrene-acrylonitrile copolymer, etc.), vinyl chloride resin, polycarbonate resin, polysulfone Resin, polyphenylene ether resin, polyphenylene sulfide resin, polyvinyl alcohol resin, cellulose ester resin, etc.), glass, ceramics, metal and the like. In addition, the adhesive agent containing a photo-acid generator uses a translucent sheet | seat suitably as a base material sheet.

  The thickness of the base sheet may be, for example, about 5 to 300 μm (for example, 7 to 200 μm), preferably 10 to 100 μm, and more preferably about 15 to 80 μm. In addition, the substrate sheet may be formed by a conventional surface treatment such as oxidation treatment [surface oxidation treatment, eg, discharge treatment (corona discharge treatment, glow discharge, etc.), acid treatment (chromic acid treatment, etc.), ultraviolet irradiation treatment, soot Surface treatment such as treatment, etc., surface unevenness treatment (solvent treatment, sandblast treatment, etc.) may be applied.

  The laminated sheet can be obtained by a method of coating an adhesive on the base sheet, a method of laminating (adhering) the base sheet and the sheet-like adhesive, or the like.

  The polymer contained in the adhesive of the present invention has high adhesiveness (particularly hot-melt adhesiveness) and has a property that the polymer is easily decomposed by an acid. That is, the adhesive of the present invention not only adheres the adherend, but also the acid is generated from the acid generator, so that the polymer is decomposed and the adhesive strength is reduced, so that it can be easily peeled off (non-adhered state). Become. Therefore, the adhesive of the present invention (particularly, an adhesive containing an acid generator) is useful as a temporary fixing or an adhesive for temporary adhesion for peeling off adherends adhered to each other by irradiation with active energy rays. .

  Such a temporary fixing adhesive is suitable for processing or protecting a workpiece. For example, the temporary fixing adhesive is suitable as an adhesive for a temporary adhesive tape for separating or peeling the adherend and the adhesive layer after temporarily adhering the adherend.

  The bonding method of the present invention includes a step (bonding step) of bonding adherends to each other using the adhesive. Further, in the temporary fixing method (temporary bonding method or temporary bonding method) of the present invention, an adhesion step of bonding adherends to each other using the adhesive (an adhesive containing an acid generator), Among the adherends, at least an adhesion interface (adhesion interface bonded by an adhesive) is irradiated with active energy rays to decompose the polymer, and a separation process is performed to separate the adherends adhered to each other. .

  More specifically, the temporary fixing adhesive (temporary adhesive) of the present invention includes, for example, an adhesion process for bonding one surface of a workpiece as an adherend and a fixed member, and a processing means. A processing step for processing the other surface of the workpiece, a decomposition step for decomposing the polymer by irradiating active energy rays at least on the bonding interface, and a separation step for separating the fixed member and the processed workpiece It is useful for applying to a method for manufacturing a processed member (or a method for processing a member to be processed).

  Furthermore, the adhesive of the present invention can also be used as an adhesive for a protective tape for temporarily protecting the surface of the adherend. That is, the surface of the adherend is covered or protected with at least the adhesive, the adherend is processed, and at least the adhesive interface (adhesive interface bonded by the adhesive) is irradiated with active energy rays, and the adhesive is used. A processed member can be manufactured by separating the adherend from the formed coating or protective layer. Specifically, the adhesive (temporary adhesive) of the present invention is a coating step for covering or protecting one surface of a workpiece as an adherend with at least an adhesive (an adhesive containing an acid generator). A processing step of processing the other surface of the processed member by the processing means, a decomposition step of decomposing the polymer by irradiating at least an adhesive interface with an active energy ray, a processed processed member and a covering adhesive layer Can be freely applied to a method for manufacturing a processed member (or a method for processing a member to be processed), including a separation step of separating the two.

  The temporary adhesive tape and the protective tape may have a single layer structure formed of the adhesive, or may have a laminated structure of a base sheet and an adhesive layer as described above. Good. Further, the surface of the adhesive layer (both surfaces of the adhesive layer in the case of a single-layer structure tape, and the surface of the adhesive layer in the case of a laminated structure tape) may be covered or laminated with a release sheet. As the temporary adhesive tape and the protective tape, a laminated tape in which a release sheet is laminated on a release surface (adhesive surface) is usually used.

  In the bonding step or the coating step, the adherend may be bonded or covered with an adhesive, and the type of the adherend is not particularly limited, and various molded articles or processed articles having an adhesive surface, for example, plastic molded articles , A glass substrate, a ceramic substrate, a metal substrate, and the like, and any of an electrical insulator, a semiconductor, and a conductor. The shape of the adherend may be a block shape, a plate shape such as a silicon wafer, or a sheet shape. In addition, when using an adhesive agent with the form of a laminated structure with the said base material sheet, the said base material sheet may form a protective layer.

  The adhesive may be coated on the adherend and dried as necessary. The sheet-like adhesive may be laminated on the adherend by a method such as thermal lamination. The thickness of the adhesive layer after drying may be, for example, about 0.1 to 300 μm, preferably 1 to 200 μm, more preferably about 2 to 100 μm (for example, 5 to 50 μm).

  In the bonding step, the adhesive may be heated and bonded by hot melt (thermal fusion). In hot melt bonding, the heating temperature (hot melt bonding temperature) may be, for example, 30 to 150 ° C., preferably 50 to 130 ° C., and more preferably about 80 to 120 ° C. In the bonding step, an adhesive layer or a protective layer may be formed on the adherend under pressure as necessary. Further, the protective layer is not limited to the entire surface of the non-processed surface of the adherend, but regularly or on a non-processed surface or a desired portion of the processed surface using a printing technique (including pattern coating) or the like. It may be formed irregularly partially or in a predetermined pattern.

  In the processing of the adherend, the fixed member and the processing means are only required to move or move relative to each other. For example, one of the fixed member and the processing means is close to the other or It may be separable or both may be close or separable. One may be rotatable with respect to the other, and both may be rotatable (rotatable in the same or different directions).

  In the processing step, various processing, for example, corrosion processing by coating, chemical processing such as corrosion or etching processing by an etching solution, plating processing (chemical plating, electrolytic plating processing, etc.); electrical processing such as plasma etching Processing: Optical processing with a light beam such as a laser beam (unevenness processing, etc.); mechanical processing such as polishing, cutting or grinding, and polishing can be employed. In particular, the temporary adhesive (sheet-like temporary adhesive) is suitable as a protective tape, for example, an adhesive for a back grind tape (or an adhesive for forming an adhesive layer of the back grind tape). The member may be a member to be polished such as a wafer. The protective tape (back grind tape) is bonded to one surface of the workpiece (for example, an uneven surface such as a circuit surface of a wafer) to protect the surface, and the other surface is processed (polishing, etc.) ) Can be used when With this protective tape, one surface (protective surface) of the workpiece can be protected from external foreign matters, generation of cracks, particle adhesion, and the like.

  In the back grinding process, the member to be polished (wafer or the like) is polished by polishing the other surface (surface opposite to the bonding surface) of the member to be polished while fixing the member to be fixed by an appropriate fixing means. Can be polished. The thickness of the polished member (wafer or the like) after polishing may be, for example, about 1 to 1000 μm, preferably 5 to 700 μm, and more preferably about 10 to 500 μm (for example, 30 to 400 μm).

  In the decomposition process, at least the adhesive interface is irradiated with active energy rays. The active energy ray may be either a heat ray or an actinic ray, or both. Usually, at least a heat ray is applied (heated) with a thermal acid generator, and at least an actinic ray is applied (irradiated) with a photoacid generator.

  The heating temperature may be, for example, 60 to 170 ° C, preferably 80 to 160 ° C, and more preferably about 100 to 150 ° C.

As the active light, radiation, ultraviolet light, visible light or the like can be used, and it may be usually ultraviolet light. As the light source, for example, in the case of ultraviolet rays, a low-pressure mercury lamp, a high-pressure mercury lamp, an ultrahigh-pressure mercury lamp, a halogen lamp, a laser light source, or the like can be used. The irradiation amount (irradiation energy), for example, 10 to 10000 mJ / cm ^2, preferably 30~7000mJ / cm ^2, more preferably about 100~5000mJ / cm ^2. The irradiation time is not particularly limited, and may be, for example, about 5 seconds (for example, 10 seconds to 10 minutes), preferably about 15 seconds or more (for example, 20 seconds to 5 minutes).

  In a preferred method, an adhesive containing a photoacid generator is used, and an active energy ray is irradiated in the decomposition step to generate an acid from the acid generator. In particular, heating (after-cure or post-bake) may be performed after irradiation with actinic rays. The temperature of the heat treatment may be, for example, about 80 to 180 ° C, preferably 100 to 170 ° C, more preferably about 120 to 160 ° C. The heat treatment time may be, for example, about 3 seconds or more (for example, 5 seconds to 10 minutes), preferably about 5 seconds or more (for example, 7 seconds to 5 minutes).

  In such a decomposition step, the polymer is decomposed, and the adhesive force by the adhesive is greatly reduced. Therefore, in the separation step, the adherend (such as a processed member such as a polished wafer) can be easily separated from the adhesive layer. In normal separation, one of the adherend and the adhesive layer is peeled off from the other (for example, the end of the adhesive layer is lifted obliquely upward from the adherend and peeled off). However, in such a method, stress may act on a processed member with low strength (such as a thin processed member such as a polished wafer) that has been processed, and cracks may occur. is there. On the other hand, the adhesive of the present invention has extremely low adhesiveness after decomposition, so that the adherend can be easily separated from the adhesive layer. For example, separating the adherend by simply sliding the adherend (wafer) with respect to the adhesion surface (sliding the adherend along the adhesion interface) in a direction in which no stress acts on the adherend. Can do. Therefore, when an excessive load cannot be applied to the adherend such as a wafer after back grinding (for example, when the adherend may be damaged), in particular, the fixing member or the adhesive layer It is preferable that the adherend is separated from the adhesive layer by sliding.

  Note that an adhesive containing the decomposed polymer may remain on the adherend (for example, a member to be polished such as a wafer) after the decomposition step. Therefore, the method of the present invention may include a cleaning step of cleaning a peeling surface (an adhesive surface with an adhesive) of an adherend (for example, a member to be polished such as a wafer) after the separation step. The cleaning may be performed by wiping off the peeling surface (adhesion surface) of the adherend, or may be cleaning with a solvent. As the solvent, an organic solvent soluble in the polymer can be used, and the adhesive component remaining on the peeled surface of the adherend can be easily removed.

[Adhesive and bonding method]
In particular, such a temporary fixing method (temporary bonding method) can be applied to the back grinding treatment of a member to be polished (such as a wafer) as described above. Specifically, the processing method (polishing method, manufacturing method of a polished member to be polished (wafer or the like)) of the member to be polished (wafer or the like) of the present invention includes the adhesive and a wafer as an adherend. A bonding step of bonding (or laminating the adhesive on a member to be polished (such as a wafer)) to obtain a laminate;
A polishing process (back grind process) for polishing a surface opposite to the adhesive surface (back grind process) of the member to be polished (wafer etc.) constituting the laminate;
Of the laminated body after polishing, a decomposition step of decomposing the adhesive with an acid generated from the acid generator by irradiating at least the adhesive interface with active energy rays;
A separation step of separating the polished member (wafer or the like) as an adherend from the laminated body and the decomposed adhesive.

  The adhesive of the present invention is not particularly limited to temperature, and can be decomposed by acid over a wide range of temperatures. Therefore, the decomposition step can be performed in a wide temperature range (for example, normal temperature to 150 ° C.) regardless of whether the acid generator is a thermal acid generator.

  Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples.

The number average molecular weight (Mn), weight average molecular weight (Mw), and molecular weight distribution (Mw / Mn) of the polymer are in terms of polystyrene, and are 40 ° C using a chloroform solvent and GPC (gel permeation chromatography). It was measured by. As standard substances, three polystyrene gel columns (Mn = 292 to 1.09 × 10 ⁶ ) having different molecular weights were used.

  The viscosity was measured using a rheometer (manufactured by Physica MCR301), setting a swing angle (γ (gamma) = 5%) and applying vibration at a frequency of 10 Hz.

Example 1 (2-chloroethyl vinyl ether-benzaldehyde copolymer)
To the reaction vessel, 2.96 mL of toluene, 0.43 mL of 1,4-dioxane, 0.3 mL of 2-chloroethyl vinyl ether (CEVE), and 0.31 mL of benzaldehyde (BzA) were sequentially added. To this mixed solution, 0.5 mL of 40 mM ethanesulfonic acid solution (prepared by diluting 200 mM ethanesulfonic acid solution [DCM (dichloromethane)] with toluene) and 0.5 mL of 40 mM gallium chloride solution were added at −78 ° C., The reaction was allowed to proceed for 48 hours. Quenching with ammoniacal methanol solution and post-treatment operations such as extraction were performed to obtain 0.5686 g of solid (yield 89%). ^{As a result of 1} H-NMR analysis (CDCl ₃ solvent), the content of BzA units was 47 mol%, and it was confirmed that the copolymer was an alternating copolymer of CEVE and BzA. The number average molecular weight (Mn) of the obtained copolymer was 18100, and the molecular weight distribution (Mw / Mn) was 1.11. In addition, the viscosity at 100 degrees C of the obtained copolymer was 0.1 Pa.s.

  When a 0.75 wt% acetone solution of the obtained copolymer was treated with hydrochloric acid (0.50 M) at 30 ° C. for 30 minutes, a single low molecular weight compound was obtained (confirmed by GPC).

The adhesion test of the obtained copolymer was performed as follows. That is, a copolymer is dissolved in ethyl acetate to prepare a 50% by weight solution, and 5 parts by weight of an acid generator (triphenylsulfonium perfluoro-1-butanesulfonate) is added to 100 parts by weight of the copolymer. A mixed resin solution was obtained by mixing. This mixed resin solution is applied to a silicon substrate by spin coating (1000 rpm) and vacuum-dried at 100 ° C. for 1 hour to form a coating film (adhesive layer) having a thickness of 3 μm. Further, the adhesive layer and quartz glass are bonded to each other. Bonding was performed while applying pressure at 100 ° C. In addition, the adhesive layer became sticky by heating at 100 ° C., and exhibited hot-melt adhesiveness. Moreover, the size of the coating film (adhesion part) was 5 cm ² (20 mm × 25 mm).

The adhesive strength of the adhesive layer was measured at room temperature as the minimum strength per unit area (tensile strength) when the quartz glass (and silicon) was pulled parallel to the adhesive surface (coating surface) and peeled off. However, it was 35 N / cm ² .

And, after irradiating ultraviolet light (365 nm, 800 mJ, 40 seconds) using an ultraviolet light irradiation machine (USHIO, SPOT CURE UIS-25102, high-pressure mercury lamp) on the bonded portion and baking at 150 ° C. for 10 seconds, When the tensile strength was measured in the same manner as described above, it was 0.2 N / cm ² , and the adhesive strength was remarkably reduced, and it was in a state of being easily peeled off (splitting simply by sliding the quartz glass parallel to the adhesive surface) ) In addition, when the coating film formation part (adhesive residue) of the silicon substrate was washed with tetrahydrofuran, the silicon substrate could be easily washed without remaining undissolved.

Example 2 (isobutyl vinyl ether-p-tolubenzaldehyde copolymer)
Implemented except that 0.32 mL of isobutyl vinyl ether (IBVE) and 0.35 mL of p-tolualdehyde (p-MeBzA) were sequentially added instead of 0.31 mL of 2-chloroethyl vinyl ether (CEVE) and benzaldehyde (BzA) 0.31 mL. In the same manner as in Example 1, 0.5684 g of solid was obtained (yield 89%). ^{As a result of 1} H-NMR analysis (CDCl ₃ solvent), the content of MOBzA units was 47 mol%, and it was confirmed to be an alternating copolymer of IBVE and p-MeBzA. The number average molecular weight (Mn) of the obtained copolymer was 14400, and the molecular weight distribution (Mw / Mn) was 1.22. The viscosity of the obtained copolymer at 100 ° C. was 0.1 Pa · s.

  When a 0.75 wt% acetone solution of the obtained copolymer was treated with hydrochloric acid (0.50 M) at 30 ° C. for 30 minutes, a single low molecular weight compound was obtained (confirmed by GPC).

The adhesion test of the obtained copolymer was conducted in the same manner as in Example 1. As a result, the adhesive layer became sticky by heating at 100 ° C. and exhibited hot melt adhesiveness. At room temperature, quartz glass (and silicon) was pulled in parallel to the adhesion surface (coating surface), and the adhesive strength of the adhesive layer was measured to be 37 N / cm ² . Furthermore, after irradiating an adhesive part with ultraviolet light (365 nm, 800 mJ, 40 seconds) and baking at 150 ° C. for 10 seconds, the tensile strength was measured in the same manner as described above, which was 0.3 N / cm ^2. It was extremely lowered and easily peeled off (it could be peeled off simply by sliding the quartz glass parallel to the bonding surface). In addition, when the coating film formation part (adhesive residue) of the silicon substrate was washed with tetrahydrofuran, the silicon substrate could be easily washed without remaining undissolved.

Example 3 (isobutyl vinyl ether-p-methoxybenzaldehyde copolymer)
Example 1 except that 0.32 mL of isobutyl vinyl ether (IBVE) and 0.42 mL of p-methoxybenzaldehyde (MOBzA) were used instead of 0.3 mL of 2-chloroethyl vinyl ether (CEVE) and 0.31 mL of benzaldehyde (BzA). Similarly, 0.6383 g of a solid was obtained (yield 89%). ^{As a result of 1} H-NMR analysis (CDCl ₃ solvent), the content of MOBzA units was 47 mol%, and it was confirmed that the copolymer was an alternating copolymer of IBVE and MOBzA. The number average molecular weight (Mn) of the obtained copolymer was 18100, and the molecular weight distribution (Mw / Mn) was 1.11. The viscosity of the obtained copolymer at 100 ° C. was 0.1 Pa · s.

  When a 0.75 wt% acetone solution of the obtained copolymer was treated with hydrochloric acid (0.50 M) at 30 ° C. for 30 minutes, a single low molecular weight compound was obtained (confirmed by GPC).

The adhesion test of the obtained copolymer was conducted in the same manner as in Example 1. As a result, the adhesive layer became sticky by heating at 100 ° C. and exhibited hot melt adhesiveness. At room temperature, quartz glass (and silicon) was pulled in parallel to the adhesive surface (coating surface), and the adhesive strength of the adhesive layer was measured to be 33 N / cm ² . Further, the adhesive part was irradiated with ultraviolet light (365 nm, 800 mJ, 40 seconds), baked at 150 ° C. for 10 seconds, and then measured for tensile strength in the same manner as described above. As a result, the adhesive strength was 0.4 N / cm ^2. It was extremely lowered and easily peeled off (it could be peeled off simply by sliding the quartz glass parallel to the bonding surface). In addition, when the coating film formation part (adhesive residue) of the silicon substrate was washed with tetrahydrofuran, the silicon substrate could be easily washed without remaining undissolved.

  The adhesive of the present invention has excellent adhesiveness and can achieve both adhesiveness and decomposability. Therefore, it is suitable as an adhesive for temporary fixing. In particular, the adhesive of the present invention is useful as an application that requires ease of peeling after bonding, for example, an adhesive in back grinding.

Claims (18)

The following formulas (1) and (2)

(Wherein R ¹ represents an alkyl group, an alkenyl group, a cycloalkyl group, an aryl group or an aralkyl group, and R ² represents a hydrogen atom, an alkyl group, an alkenyl group, a cycloalkyl group, an aryl group or a heterocyclic group. And at least one group selected from the alkyl group, alkenyl group, cycloalkyl group, aryl group, aralkyl group and heterocyclic group may have a substituent)
An adhesive comprising a polymer having a unit represented by formula as a repeating unit. R ¹ is a linear or branched C _1-10 alkyl group, a linear or branched C _2-10 alkenyl group or a C _5-10 cycloalkyl group, and these alkyl groups, alkenyl groups and The cycloalkyl group may have at least one substituent selected from a halogen atom and an alkoxy group; R ² is selected from a halogen atom, an alkyl group, an alkoxy group, an alkoxyalkyl group, a nitro group The adhesive according to claim 1, which is an aryl group which may have at least one substituent. R ¹ is a linear or branched C _1-6 alkyl group which may have at least one substituent selected from a halogen atom and a linear or branched C _1-4 alkoxy group. R ² is a halogen atom, a linear or branched C _1-4 alkyl group, a linear or branched C _1-4 alkoxy group, a C _1-4 alkoxy-C _1-4 alkyl group. The adhesive according to claim 1, which is a C _6-12 aryl group which may have at least one selected substituent. The unit represented by the formula (2) is the following formula (2a)

(In the formula, R ³ represents a halogen atom, an alkyl group, an alkoxy group, or an alkoxyalkyl group, p represents 0 or an integer of 1 to 5, and when the coefficient p is 2 or more, the type of R ³ is different. R ¹ is the same as above)
The adhesive according to claim 1, which is a unit represented by: The polymer is represented by the following formula (3)

(Wherein R ¹ and R ² are the same as above)
The adhesive according to any one of claims 1 to 4, which is an alternating copolymer having a repeating unit represented by:   The adhesive according to any one of claims 1 to 5, wherein the polymer has hot-melt adhesiveness.   Furthermore, the adhesive agent in any one of Claims 1-6 containing an acid generator.   The adhesive according to claim 7, which is a temporary fixing adhesive for peeling off adherends adhered to each other by irradiation with active energy rays.   The temporary adhesive tape provided with the contact bonding layer formed with the adhesive agent of Claim 7 or 8.   A protective tape comprising an adhesive layer formed of the adhesive according to claim 7 or 8.   An adhesion step of adhering adherends to each other using the adhesive according to claim 7 or 8, and a decomposition step of decomposing a polymer by irradiating at least an adhesive interface with active energy rays among the adherends to be adhered. And a separation step of separating the adherends adhered to each other.   Using the adhesive according to claim 7 or 8, an adhesion step of bonding one surface of a workpiece as an adherend and a fixed member that can move relative to the processing means, and processing A processing step of processing the other surface of the workpiece by means, a decomposition step of irradiating at least an adhesive interface with active energy rays to decompose the polymer, and a fixed member and the processed workpiece are separated. A method for producing a processed member including a separation step.   A coating step of covering at least one surface of a workpiece as an adherend with the adhesive according to claim 7 or 8, a processing step of processing the other surface of the workpiece by a processing means, and at least adhesion A method for producing a processed member, comprising: a decomposition step of irradiating an active energy ray on an interface to decompose a polymer; and a separation step of separating the processed member and the coated adhesive layer.   A covering step of covering at least one surface of a member to be polished as an adherend with the adhesive according to claim 7 or 8, a polishing step of polishing the other surface of the member to be polished by a polishing means, and at least adhesion A method for producing a polished member, comprising: a decomposition step of irradiating an interface with active energy rays to decompose a polymer; and a separation step of separating a polished member to be polished and a coated adhesive layer.   The method according to any one of claims 11 to 14, wherein an adhesive containing a photoacid generator is used, and the polymer is decomposed with an acid generated from the acid generator in the decomposition step by irradiation with an active energy ray and heating. .   The method according to claim 11, wherein in the bonding step, the adhesive is heated and bonded by hot melt.   The method according to any one of claims 11 to 16, wherein, in the separation step, the adherend is separated by sliding with respect to the adhesive layer.   The method according to any one of claims 11 to 17, further comprising a cleaning step of cleaning the peeled surface of the adherend after the separation step.