JP2009185197A - Adhesive composition, its use, and method for producing adhesive composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an adhesive composition having alkaline hyperhydration tolerance, high heat resistance, adhesive strength in a high-temperature environment, and high alkali resistance and allowing easy peeling after a high-temperature process. <P>SOLUTION: In the adhesive composition principally comprising a polymer obtained by copolymerization of monomers including a styrene monomer and a (meth)acrylic acid ester monomer, an antioxidant is mixed. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

  The present invention relates to an adhesive composition and use thereof, and a method for producing the adhesive composition. In particular, in a process such as grinding of a semiconductor product such as a semiconductor wafer or an optical system product, the semiconductor product, the optical system product, etc. The present invention relates to an adhesive composition, an adhesive film and the like and a method for producing an adhesive composition for temporarily fixing a sheet and a protective substrate.

  In recent years, with the enhancement of functions of mobile phones, digital AV devices, IC cards, and the like, there is an increasing demand for downsizing, thinning, and high integration of semiconductor silicon chips (hereinafter referred to as chips). For example, an integrated circuit that integrates a plurality of chips into one package such as CSP (chip size package) and MCP (multi-chip package) is required to be thin. Among them, the system-in-package (SiP) in which a plurality of semiconductor chips are mounted in one semiconductor package makes the mounted chip smaller, thinner and highly integrated, and enhances the performance of electronic devices. It has become a very important technology for realizing miniaturization and weight reduction.

  In order to meet the needs for thin products, it is necessary to make the chip as thin as 150 μm or less. Further, it is necessary to thin the chip to 100 μm or less for CSP and MCP and 50 μm or less for IC card.

  Conventionally, a method of wiring bumps (electrodes) for each stacked chip and a circuit board by wire bonding technology is used for SiP products. In addition, in order to meet such demands for thinning and high integration, instead of wire bonding technology, it is necessary to use a through electrode technology in which chips with through electrodes are stacked and bumps are formed on the back surface of the chip. It becomes.

  For example, a thin chip is obtained by slicing a high-purity silicon single crystal or the like into a wafer, etching a predetermined circuit pattern such as an IC on the wafer surface, incorporating an integrated circuit, and mounting the back surface of the obtained semiconductor wafer. It is manufactured by grinding with a grinder and dicing the semiconductor wafer after grinding to a predetermined thickness to form chips. At this time, the predetermined thickness is about 100 to 600 μm. Furthermore, when forming a penetration electrode, it grinds to about 50-100 micrometers in thickness.

  In the manufacture of semiconductor chips, the semiconductor wafer itself is thin and fragile, and the circuit pattern has irregularities, so that it is easily damaged when an external force is applied during conveyance to a grinding process or a dicing process. Further, in the grinding process, grinding is performed while removing generated polishing debris and washing the back surface of the semiconductor wafer with purified water in order to remove heat generated during polishing. At this time, it is necessary to prevent the circuit pattern surface from being contaminated by the purified water used for cleaning.

  Therefore, in order to protect the circuit pattern surface of the semiconductor wafer and prevent damage to the semiconductor wafer, a grinding operation is performed after a processing adhesive film is attached to the circuit pattern surface.

  Also, when dicing, a protective sheet is attached to the back side of the semiconductor wafer, and the dicing is performed with the semiconductor wafer adhered and fixed. ing.

  Examples of such processing adhesive films and protective sheets include adhesive compositions on base films such as polyethylene terephthalate (PET), polyethylene (PE), polypropylene (PP), and ethylene-vinyl acetate copolymer (EVA). Those provided with an adhesive layer formed from an object are known (for example, Patent Document 1, Patent Document 2, and Patent Document 3).

  In addition, instead of a processing adhesive film or protective sheet, a protective substrate in which a ladder-type silicone oligomer is impregnated with an aluminum nitride-boron nitride pore sintered body is used, and this protective substrate and a semiconductor wafer are bonded using a thermoplastic film. The structure which does is also disclosed (patent document 4). In addition, a material such as alumina, aluminum nitride, boron nitride, or silicon carbide having a thermal expansion coefficient substantially the same as that of the semiconductor wafer is used as the protective substrate, and a thermoplastic such as polyimide is used as an adhesive for bonding the protective substrate and the semiconductor wafer. As a method of applying this adhesive using a resin, there are proposed a configuration in which the film has a thickness of 10 to 100 μm and a method in which the adhesive composition is spin-coated and dried to form a film of 20 μm or less ( Patent Document 5).

  In addition, with the multi-layer wiring of semiconductor elements, a protective substrate is adhered to the surface of a semiconductor wafer on which a circuit is formed using an adhesive composition, the back surface of the semiconductor wafer is polished, and then the polished surface is etched. A process of forming a back surface circuit on the mirror surface is performed. In this case, the protective substrate remains adhered until the back side circuit is formed (Patent Document 6).

As described above, by adhering a high strength material to a thin semiconductor wafer, the semiconductor wafer is protected and the strength is maintained. However, the adhesive composition used for the adhesion and the processing adhesive are used. Films are required to have properties that do not deteriorate or deteriorate not only in grinding and dicing processes but also in high-temperature processes, etching processes, wet processes such as plating and cleaning.
JP 2003-173993 A (released on June 20, 2003) JP 2001-279208 A (published October 10, 2001) JP 2003-292931 A (released on October 15, 2003) JP 2002-203821 (published July 19, 2002) JP 2001-77304 A (published March 23, 2001) Japanese Patent Laid-Open No. 61-158145 (released July 17, 1986)

  However, conventional adhesive compositions and processing pressure-sensitive adhesive films are not sufficient in the property that they do not cause deterioration or deterioration even in high-temperature processes, etching processes, wet processes such as plating and cleaning.

  In particular, the resistance to alkaline water used for etching and cleaning is not sufficient, and there is a problem that the adhesive layer and the pressure-sensitive adhesive film for processing are peeled off or cracked in these processes.

  The present invention has been made in view of such problems, and has adhesion to alkali overwater, and has high heat resistance, particularly low moisture absorption at 140 ° C. to 200 ° C., and excellent flexibility in a high temperature environment. It is to provide an agent composition.

  As a result of intensive studies in view of the above problems, the present inventors have found that a polymer (A) obtained by copolymerizing a monomer containing a styrene monomer and a (meth) acrylic acid ester monomer. ) And the antioxidant composition containing the antioxidant (B) are resistant to alkaline water, and have high heat resistance, particularly low moisture absorption at 140 ° C. to 200 ° C., and excellent flexibility in a high temperature environment. As a result, the present invention has been completed.

  That is, the adhesive composition according to the present invention is a polymer obtained by copolymerizing a monomer containing a styrene monomer and a (meth) acrylic acid ester monomer in order to solve the above problems. It is the adhesive composition which has (A) as a main component, Comprising: Antioxidant (B) is contained, It is characterized by the above-mentioned.

  According to said structure, the alkali-water resistance of the adhesive bond layer containing the said adhesive composition can be improved.

  In the adhesive composition according to the present invention, the antioxidant (B) is preferably a hindered amine antioxidant and / or a hindered phenol antioxidant.

  In the adhesive composition according to the present invention, the content of the antioxidant (B) is preferably 1% by mass or more and less than 30% by mass with respect to the polymer (A).

  In the adhesive composition according to the present invention, the antioxidant (B) contains 4,4-thiobis (6-t-butyl-m-cresol) and 3,9-bis [2- [3- ( 3-t-butyl-4-hydroxy-5-methylphenyl) -propionyloxy] -1,1-dimethyl] -2,4,8,10-tetraoxaspiro (5,5) undecane It is more preferable that

  In the adhesive composition according to the present invention, the (meth) acrylic acid ester monomer includes a (meth) acrylic acid ester having a cyclic structure and a (meth) acrylic acid ester having a chain structure. Is preferred.

  The heat resistance can be further improved by including the (meth) acrylate ester having a cyclic structure and the (meth) acrylate ester having a chain structure. In addition, there is an additional effect that the flexibility and crack resistance of the adhesive layer can be improved.

  The adhesive composition according to the present invention preferably further contains an antioxidant auxiliary agent (C). The antioxidant assistant (C) is more preferably a phosphorus antioxidant and / or a sulfur antioxidant.

  When the said adhesive composition further contains antioxidant adjuvant (C), there exists the further effect that the alkaline overwater tolerance of the adhesive composition obtained can be improved further.

  In the adhesive composition concerning this invention, it is preferable that content of the said antioxidant adjuvant (C) is 5 mass% or more and less than 200 mass% with respect to the said antioxidant (B).

  In the adhesive composition according to the present invention, the antioxidant aid (C) is preferably ditridecyl-3,3'-thiodipropionate.

  The adhesive film concerning this invention is equipped with the adhesive bond layer containing the said adhesive composition on a film, It is characterized by the above-mentioned.

  Since the adhesive film includes an adhesive layer containing the adhesive composition on the film, the adhesive film has alkali overwater resistance, and has heat resistance, adhesive strength in a high temperature environment, and alkali resistance. An adhesive film having an adhesive layer excellent in ease of peeling can be obtained.

  In order to solve the above problems, a method for producing an adhesive composition according to the present invention is a method for producing an adhesive composition having alkaline water resistance, and includes a styrene monomer and (meth) acrylic acid. A method for producing an adhesive composition comprising, as a main component, a polymer (A) obtained by copolymerizing a monomer containing an ester monomer, wherein the antioxidant (B) is added to the polymer (A). It is characterized by including a mixing step of mixing.

  According to said structure, while having alkali-water resistance, it can obtain the adhesive composition which has high heat resistance in 140 degreeC-200 degreeC especially in high temperature environment, low hygroscopicity, and the outstanding softness | flexibility. There is an effect.

  As described above, the adhesive composition according to the present invention mainly comprises a polymer (A) obtained by copolymerizing a monomer containing a styrene monomer and a (meth) acrylic acid ester monomer. Since it is an adhesive composition as a component and has a structure containing an antioxidant (B), it has excellent resistance to alkaline water resistance and high heat resistance, particularly at 140 ° C to 200 ° C, and low in a high temperature environment. It has the effect of having hygroscopicity and excellent flexibility.

  Hereinafter, the adhesive composition and the use thereof according to the present invention, and the method for producing the adhesive composition, (I) Adhesive composition, (II) Use of adhesive composition, (III) Production of adhesive composition Specific description will be given in the order of the method.

(I) Adhesive composition The adhesive composition according to the present invention is a polymer (A) obtained by copolymerizing a monomer containing a styrene monomer and a (meth) acrylate monomer. It is the adhesive composition which has as a main component, Comprising: Antioxidant (B) is included.

  Here, in the present specification, the “main component” refers to a component having a higher content than any other component contained in the adhesive composition. Therefore, the content of the main component is not particularly limited as long as it is the largest amount among the components contained in the adhesive composition, but with respect to the mass of the adhesive composition, It is preferably 50% by mass or more and less than 99% by mass, and more preferably 70% by mass or more and less than 99% by mass. When the content of the main component, that is, the polymer (A) is 50% by mass or more, the adhesive composition has high heat resistance, high adhesive strength in a high temperature environment, alkali resistance, and peeling. It is preferable because of its ease.

  In the present specification, the term “(meth) acryl” is used to mean “acryl” or “methacryl”.

  The adhesive composition according to the present invention contains an antioxidant (B). In the adhesive composition according to the present invention, excellent alkaline overwater resistance can be achieved by containing the antioxidant (B).

  Here, the alkaline perwater is not particularly limited as long as it is a mixture of an alkaline compound, a hydrogen peroxide solution, and water. For example, it is a mixture of ammonia, a hydrogen peroxide solution, and water. Mention may be made of ammonia overwater.

  Further, the mixing ratio of the alkaline compound, hydrogen peroxide solution, and water is not particularly limited. For example, the volume ratio of the alkaline compound: hydrogen peroxide: water is 0.5-2: 0.5- 2: 10-40.

  In the present invention, the alkali water resistance refers to the resistance to the alkali water, more specifically, when immersed in the alkali water having a temperature of 50 ° C. or more and less than 90 ° C. for 5 minutes or more and less than 20 minutes. It refers to the tolerance of.

For example, when the alkaline hydrogen peroxide is ammonia hydrogen peroxide, the ammonia hydrogen peroxide is a mixture of ammonia: hydrogen peroxide (H ₂ O ₂ ): water (H ₂ O), and the volume ratio is For example, it is 0.5-2: 0.5-2: 10-40.

  The adhesive composition according to the present invention only needs to contain the polymer (A) as a main component and an antioxidant (B), but further contains an antioxidant auxiliary agent (C). Preferably, "other components" other than the polymer (A), the antioxidant (B), and the antioxidant auxiliary agent (C) may be included.

(I-1) Polymer (A)
The polymer (A) used in the adhesive composition according to the present invention is a polymer obtained by copolymerizing a monomer containing a styrene monomer and a (meth) acrylic acid ester monomer. Good. Above all, the polymer (A) is obtained by copolymerizing a monomer containing 60% by mass or more of a styrene monomer and a (meth) acrylate monomer with respect to the total amount of all monomer components. More preferably, the polymer is: Accordingly, the polymer (A) may be a polymer obtained by copolymerizing only a styrene monomer and a (meth) acrylic acid ester monomer. May be used in such a range that the total amount thereof is less than 40% by mass with respect to the total amount of all monomer components.

That is, the polymer (A) is at least a structural unit (i) represented by the following formula derived from a styrene monomer.
_{- (- CH (C 6 H} 5) -CH 2 -) - ··· (i)
And a structural unit (ii) represented by the following formula derived from a (meth) acrylic acid ester monomer:
_- (- CH 2 -C (H or ^{_{CH 3) (COOR 1) -}} ) - ··· (ii)
(In the formula, R ¹ represents an organic group.)
And a structural unit derived from “another monomer component”.

  Since the structural unit (i) derived from the styrenic monomer does not change even under a high temperature environment of 200 ° C. or higher, the heat resistance of the obtained adhesive composition can be improved.

  Moreover, by including the structural unit (ii) derived from the (meth) acrylic acid ester monomer, the heat resistance of the obtained adhesive composition is further improved, and the adhesive layer containing the adhesive composition Flexibility and crack resistance can be further improved.

  The amount of the styrenic monomer used relative to the total amount of all monomer components is not particularly limited as long as the copolymerization reaction proceeds, but it is more preferably 30% by mass or more and less than 90% by mass, and 40% by mass. % Or more and less than 60% by mass. If the amount of the styrene monomer used relative to the total amount of all monomer components is 30% by mass or more, the heat resistance can be improved, which is preferable. Moreover, if content of the styrene-type monomer with respect to the total amount of all the monomer components is less than 90 mass%, since the fall of crack tolerance can be suppressed, it is preferable.

  The amount of the (meth) acrylic acid ester monomer used relative to the total amount of all monomer components is not particularly limited as long as the copolymerization reaction proceeds, but it is 10% by mass or more and less than 70% by mass. It is more preferable that the content is 20% by mass or more and less than 50% by mass. When the content of the (meth) acrylic acid ester monomer with respect to the total amount of all monomer components is 10% by mass or more, the heat resistance of the obtained adhesive composition is further improved, and the adhesive composition It is preferable because the flexibility and crack resistance of the adhesive layer made of can be further improved. In addition, when the content of the (meth) acrylic acid ester monomer with respect to the total amount of all monomer components is less than 70% by mass, good peelability can be obtained, and the resulting adhesive composition This is preferable because the heat resistance, the peeling failure, and the hygroscopicity can be suppressed.

<Styrene monomer>
The styrene monomer is not particularly limited as long as it is a monomer that forms the structural unit (i). For example, styrene, a styrene macromonomer, and the like can be preferably used.

In the polymer (A), the structural unit (i) derived from the styrenic monomer may have a random structure copolymerized at random, or a chain composed only of the structural unit (i). Alternatively, a block structure copolymerized in block units may be used. Especially, it is more preferable that the polymer (A) has a styrene block structure in addition to the random structure for the structural unit (i). Here, the styrene block structure means a site where styrene is copolymerized in block units,
A structure represented by — (— CH (C ₆ H ₅ ) —CH ₂ —) _n — (n is an integer, n ≧ 2). The repeating number n of the structural unit (i) constituting the styrene block structure may be 2 or more, more preferably 20 or more and less than 100, and still more preferably 50 or more and less than 70. Thereby, the average molecular weight of the said polymer (A) obtained becomes still larger. Therefore, dissociation between the molecular chains in the adhesive composition is suppressed, so that alteration of the adhesive composition in a high temperature environment can be prevented. This also improves the adhesive strength, and can be easily peeled even after a high temperature process.

  Moreover, in the adhesive composition mainly composed of the polymer (A) having a styrene block structure, generation of gas at the interface between the adhesive composition and the adherend can be prevented. Therefore, it is possible to obtain an adhesive composition having improved adhesive strength in a high temperature environment by preventing peeling of the adhesive composition due to gas generation at the interface during heating and vacuum.

  Furthermore, since it is possible to obtain the effect of improving the heat resistance without using a carboxylic acid having a carbon-carbon double bond, which will be described later, the alkali resistance of the obtained adhesive composition is further improved. Can do.

  Therefore, heat resistance, adhesive strength in a high temperature environment (especially 140 ° C. to 200 ° C.), and ease of peeling after a high temperature process can be further improved.

  As the styrene monomer, for example, when styrene is used and copolymerization is started after mixing with a monomer other than the styrene monomer, the structural unit (i) is randomly copolymerized. Can be obtained. For example, when a styrene macromonomer is used as the styrene monomer, a copolymer having a styrene block structure can be obtained.

The styrene macromonomer has a styrene block structure — (— CH (C ₆ H ₅ ) —CH ₂ —) _n — (n is an integer, n ≧ 2) in the structure, and is particularly capable of being copolymerized. Although not limited, it consists of a styrene block structure and organic groups located at both ends of the styrene block structure, and at least one of the organic groups has a carbon-carbon double bond. More preferred is a styrene macromonomer. The styrene macromonomer is represented by the following general formula (1)
R ² — (— CH (C ₆ H ₅ ) —CH ₂ —) _n —R ³ (1)
It is more preferable that it is a styrene macromonomer shown by these. Here, in General Formula (1), R ² and R ³ each independently represent an organic group having 1 to 10 carbon atoms having at least one carbon-carbon double bond.

  In addition, the repeating number n of the structural unit (i) constituting the styrene block structure in the styrene macromonomer is not particularly limited, and the properties of the adhesive composition such as intended adhesive strength and heat resistance. However, it is preferably 20 or more and less than 100, more preferably 50 or more and less than 70.

  The styrene macromonomer is easily copolymerized with a monomer contained in the monomer. Therefore, the average molecular weight of the obtained polymer (A) is further increased by using the styrene macromonomer. Therefore, dissociation between molecular chains in the adhesive composition is suppressed. Therefore, the heat resistance of the adhesive composition, the adhesive strength in a high temperature environment (especially 140 ° C. to 200 ° C.), and the ease of peeling after a high temperature process can be further improved.

  Moreover, since the effect of improving heat resistance can be obtained without using a carboxylic acid having a carbon-carbon double bond described later, the alkali resistance of the obtained adhesive composition can be further improved. it can.

  More specifically, as the styrene macromonomer, for example, a macromonomer (manufactured by Toagosei Co., Ltd., grade: AS-6S), a macromonomer (manufactured by Toagosei Co., Ltd., grade: AN-6S) and the like are preferably used. Can be used. The styrene macromonomer may be used alone or in combination of two or more. The copolymerization of these styrene macromonomers and monomers other than the styrene macromonomer proceeds suitably, and the structure of the polymer (A) obtained after the copolymerization becomes more stable. Therefore, dissociation between molecular chains can be prevented, so that heat resistance and adhesive strength in a high temperature environment are improved.

  The polymer (A) more preferably has a styrene block structure in addition to the structure in which the structural units (i) are randomly copolymerized. Such a polymer (A), for example, uses styrene and a styrene macromonomer together as a styrene monomer, and starts copolymerization after mixing at least styrene with a monomer component other than the styrene monomer. Can be obtained.

  In such a case, the amount of the styrene macromonomer used is preferably 5% by mass or more and less than 40% by mass with respect to the total amount of the styrene monomer, that is, the total amount of styrene and the styrene macromonomer. % Or more and less than 20% by mass. By making the use amount of the styrene macromonomer in the above range, the obtained adhesive composition has the effect of improving the heat resistance by styrene and the effect of improving the adhesive strength in a high temperature environment by the styrene macromonomer described above. Can be effectively obtained together.

  The timing of mixing the styrene macromonomer is not particularly limited, and the styrene macromonomer may be mixed in advance with the monomer before the start of the copolymerization reaction, or other than the styrene macromonomer. The styrene macromonomer may be mixed after the copolymerization reaction of the monomer is started and before the copolymerization reaction is completed. More preferably, after the start of the copolymerization reaction of monomers other than the styrene macromonomer, the styrene macromonomer is mixed in batches or batchwise. By mixing in this way, it is possible to unevenly distribute the places where the styrene block structure derived from the styrene macromonomer is concentrated in the adhesive composition, thereby further suppressing the dissociation of molecular chains in a high temperature environment. As a result, the adhesive strength in a high temperature environment is improved.

  In this specification, “initiating a copolymerization reaction” means a copolymerization in a monomer mixture obtained by mixing monomers other than the monomers to be mixed after the above-described copolymerization reaction is started. The time when the reaction starts.

  In the actual production of the polymer (A), when the copolymerization reaction is started only by mixing the monomers to be copolymerized, the time point when the mixing of the monomer components to be mixed in advance is completed. The point of time when the polymerization reaction is started. Further, when the copolymerization reaction is started by stirring, the time point at which stirring is started may be set as the above-mentioned “starting copolymerization reaction” time point. Further, when the copolymerization reaction starts at a predetermined temperature, the time point at which the temperature is reached may be set as the time point at which the “copolymerization reaction is started”. Further, when the copolymerization reaction is started by the addition of the polymerization initiator, the time when the polymerization initiator is added may be set as the above-mentioned “starting the copolymerization reaction”. That is, according to the monomer, polymerization method, and the like, a time point of “start of copolymerization reaction” may be set as appropriate, and subsequent steps and the like may be controlled.

  Further, in the present specification, “terminating the copolymerization reaction” refers to a point in time when a desired copolymerization reaction is achieved. Specifically, the adhesive composition may be manufactured by setting the time point when the stirring is stopped, the time point when cooling is started from the reaction temperature, and the like as the time point when the copolymerization reaction is finished.

  In addition to using a styrene macromonomer, the styrene block structure uses styrene as a styrenic monomer, and after starting the copolymerization reaction of the monomer, the styrene block structure is It can also be formed by mixing.

  The formation of a styrene block structure by styrene added after the polymerization is started is performed by mixing all or part of styrene used as a monomer with monomers other than the “all or part of styrene”. After starting the copolymerization reaction, before completing the copolymerization reaction, batch or batchwise mixing into the copolymerization reaction system, that is, the reactor that is carrying out the copolymerization reaction, etc. To do so.

  When styrene is added after the start of polymerization, the copolymerization of monomers other than the above “all or a part of styrene” is almost completed, so the styrene block structure of only styrene added after the start of polymerization Is formed.

  Furthermore, it is preferable to add the styrene added after starting the said copolymerization reaction collectively, ie, the whole quantity of the said styrene at once. Moreover, it is preferable to add before half time passes among the time which a copolymerization reaction requires. If it does in this way, a styrene block segment will be suitably formed in the said adhesive composition because styrene concentrates and copolymerizes.

  The polymer (A) preferably further has a styrene block structure in addition to the structure in which the structural units (i) are randomly copolymerized. Styrene is used as a system monomer, and after a part of it is mixed with a monomer other than a styrene monomer, the copolymerization is started, and after the start of the copolymerization reaction, before the copolymerization reaction is terminated. Furthermore, it can be obtained by adding the remaining styrene and polymerizing.

  In such a case, the amount of styrene forming the styrene block structure is adjusted by the amount of styrene added after the copolymerization reaction is started. And the amount may be appropriately set according to the properties of the adhesive composition such as the desired adhesive strength, heat resistance, etc., but with respect to the total amount of styrene used in the production of the adhesive composition according to the present invention. It is preferably 5% by mass or more and less than 80% by mass, and more preferably 10% by mass or more and less than 30% by mass.

  In addition, the kind of styrene-type monomer used and the timing of mixing thereof are not limited to the above-mentioned examples, and the timing of styrenic monomer and mixing thereof may be appropriately combined. Therefore, for example, using a styrene macromonomer and starting a copolymerization after mixing a part of styrene with a monomer other than a styrene monomer, and after starting the copolymerization reaction, Before the termination, a method of polymerizing by adding the remaining styrene may be used in combination.

<(Meth) acrylic acid ester monomer>
The (meth) acrylic acid ester monomer that can be used as the monomer of the polymer (A) is not particularly limited, but a (meth) acrylic acid ester having a cyclic structure, and a chain type It is more preferable to include a (meth) acrylic acid ester having a structure.

  When the polymer (A) includes a structural unit derived from a (meth) acrylic acid ester having a cyclic structure, the heat resistance of the obtained adhesive composition can be improved. Further, even when acrylic acid described later is not used as a monomer, it is possible to ensure good releasability with the stripper.

  The content of the (meth) acrylic acid ester having a cyclic structure is preferably 5% by mass or more and less than 60% by mass with respect to the total amount of all monomer components, and is 10% by mass or more and less than 40% by mass. More preferably it is. If the content of the (meth) acrylic ester having a cyclic structure is 5% by mass or more, the heat resistance can be further improved, and if it is less than 60% by mass, good peelability is obtained. be able to.

  Moreover, the said polymer (A) contains the structural unit derived from the (meth) acrylic acid ester which consists of chain structures, The adhesive bond layer obtained from the adhesive composition which has the said polymer (A) as a main component Flexibility and crack resistance can be improved.

  The content of the (meth) acrylic acid ester having a chain structure is not particularly limited as long as the copolymerization reaction proceeds, but it is 5% by mass or more and less than 60% by mass with respect to the total amount of all monomer components. It is preferable that it is 10 mass% or more and less than 40 mass%. When the content of the (meth) acrylic acid ester having a chain structure is 5% by mass or more, the flexibility and crack resistance of the adhesive layer made of the obtained adhesive composition can be further improved. Become. Moreover, when content of the (meth) acrylic acid ester which consists of said chain structure is less than 60 mass%, the heat resistant fall of the adhesive composition obtained, peeling defect, and moisture absorption can be suppressed. .

((Meth) acrylic acid ester having a cyclic structure)
Examples of the (meth) acrylic acid ester having a cyclic structure include a structure in which a hydrogen atom of a carboxyl group in (meth) acrylic acid is substituted with an organic group having a cyclic group or a cyclic group.

  Here, the cyclic group may be an aromatic cyclic group or an aliphatic cyclic group. Further, in the present specification, “aliphatic” is a relative concept with respect to aromatics, and is defined to mean a group, a compound, or the like that does not have aromaticity. For example, “aliphatic cyclic group” refers to a cyclic group having no aromaticity.

  The cyclic group may be a monocyclic group or a polycyclic group. Furthermore, the cyclic group may be saturated or unsaturated, and the number and position of double bonds and triple bonds contained are not particularly limited. Moreover, although carbon number which comprises the said cyclic group is not specifically limited, It is more preferable that it is 3-12, and it is more preferable that it is 3-8. The cyclic group may further have a substituent described later.

  The cyclic group may be a heterocyclic group. Moreover, the kind and number of heteroatoms contained in the heterocyclic group are not particularly limited, and may contain an oxygen atom, a nitrogen atom, or the like. Among these, the cyclic group is more preferably a hydrocarbon group composed of only carbon atoms and hydrogen atoms.

  Examples of the aromatic cyclic group include a group in which one or more hydrogen atoms are removed from benzene, naphthalene, anthracene, or the like. More specific examples of the cyclic group include a phenyl group, a tolyl group, a xylyl group, a cumenyl group, a mesityl group, a 1-naphthyl group, a 2-naphthyl group, an anthryl group, and a phenanthryl group. it can.

  Specific examples of the aliphatic cyclic group include, for example, monocycloalkanes; cycloalkyl groups in which one or more hydrogen atoms have been removed from polycycloalkanes such as dicycloalkanes, tricycloalkanes, and tetracycloalkanes. Etc. More specifically, the aliphatic cyclic group includes one or more hydrogens from monocycloalkanes such as cyclopentane and cyclohexane; polycycloalkanes such as adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane. Examples include groups excluding atoms. Among these, the aliphatic cyclic group is preferably a group obtained by removing one or more hydrogen atoms from cyclohexane or dicyclopentane. Of course, the aliphatic cyclic group including the cyclohexane and dicyclopentane may further have a substituent described later.

  Examples of the substituent include a polar group such as a hydroxyl group, a carboxyl group, a cyano group, and an oxygen atom (═O), a linear or branched lower alkyl group having 1 to 4 carbon atoms, and the like. When the cyclic group further has the substituent, it preferably has the polar group, the lower alkyl group, or both the polar group and the lower alkyl group. As the polar group, an oxygen atom (═O) is particularly preferable.

  As described above, the (meth) acrylic acid ester having a cyclic structure includes a structure in which a hydrogen atom of a carboxyl group in (meth) acrylic acid is substituted with an “organic group having a cyclic group”. . Here, the “organic group having a cyclic group” is not particularly limited as long as it has the above cyclic group. For example, an alkyl having at least one hydrogen atom substituted with a cyclic group. The group can be used more suitably. Here, although carbon number of the said alkyl group is not specifically limited, It is more preferable that it is 1-20, and it is further more preferable that it is 1-12. Examples of the (meth) acrylic acid ester having such a cyclic structure include cyclohexyl-2-propyl acrylate and isobornyl (meth) acrylate.

  Further, the “organic group having a cyclic group” may be a hydroxyalkyl group in which a hydrogen atom of the hydroxy group of the hydroxyalkyl group is substituted with a cyclic group. Here, the number of carbon atoms of the hydroxyalkyl group is not particularly limited, but is preferably 1 to 12, and more preferably 1 to 4. Examples of the (meth) acrylic acid ester having such a cyclic structure include phenoxyethyl acrylate and phenoxypropyl acrylate.

  In addition, the (meth) acrylic acid ester having the above cyclic structure has a substituent on the cyclic structure, a (meth) acrylic acid ester having a cyclic structure, and a substituent on the cyclic structure. A (meth) acrylic ester containing a (meth) acrylic ester having a cyclic structure may be used in combination. Thereby, the heat resistance and softness | flexibility of the polymer (A) and adhesive composition which are obtained can be improved.

((Meth) acrylic acid ester consisting of chain structure)
As described above, the (meth) acrylic acid ester that can be used as the monomer of the polymer (A) includes (meth) acrylic acid ester having a cyclic structure and (meth) acrylic having a chain structure. It is more preferable to use an acid ester in combination.

  The (meth) acrylic acid ester having a chain structure is not particularly limited, but is more preferably an alkyl ester of (meth) acrylic acid. Among these, the (meth) acrylic acid ester having the above chain structure is preferably an alkyl ester with an alkyl group having 1 to 20 carbon atoms, and an alkyl ester with an alkyl group having 1 to 14 carbon atoms. More preferred is an alkyl ester with an alkyl group having 1 to 6 carbon atoms. Here, the alkyl group may be linear or branched.

  More specifically, as the (meth) acrylic acid alkyl ester, for example, the alkyl group is a methyl group, an ethyl group, a propyl group, a butyl group, a 2-ethylhexyl group, an isooctyl group, an isononyl group, an isodecyl group, or a dodecyl group. Examples include alkyl esters of acrylic acid or methacrylic acid which are a group, lauryl group, tridecyl group, n-pentadecyl group, n-hexadecyl group, n-heptadecyl group, n-octadecyl group, n-nonadecyl group, n-eicosyl group, etc. be able to.

<Other monomer components>
The polymer (A) is obtained by copolymerizing a monomer containing 60% by mass or more of a styrene monomer and a (meth) acrylic acid ester monomer with respect to the total amount of all monomer components. In the case of a polymer, one or more “other monomer components” may be used as a monomer.

  Such other monomer component is not particularly limited as long as it does not adversely affect the physical properties of the obtained adhesive composition. For example, a carboxylic acid having a carbon-carbon double bond, A bifunctional monomer or the like can be suitably used.

  In addition to the styrene monomer and the (meth) acrylic acid ester monomer, the polymer (A) further includes a carboxylic acid having a carbon-carbon double bond and / or a bifunctional monomer. A polymer obtained by copolymerization is more preferable. In addition to the styrene monomer and the (meth) acrylic acid ester monomer, a carboxylic acid having a carbon-carbon double bond, and two A polymer obtained by copolymerizing a functional monomer is more preferable.

(Carboxylic acid having a carbon-carbon double bond)
By using a carboxylic acid having a carbon-carbon double bond as the other monomer component, the adhesive strength of the obtained adhesive composition obtained under high temperature, particularly in an environment of 140 ° C. to 200 ° C., and heat resistance Can be further improved, and can be easily peeled off from the adherend even after a high temperature process.

  This is because the adhesive composition and the adhesive composition are applied by increasing the number of hydroxyl groups (polar groups) derived from the carboxylic acid having a carbon-carbon double bond in the adhesive composition. This is considered to be because the polarity of the adhesive composition at the interface with the adherend surface is improved, and therefore, dissociation of molecular chains in the adhesive composition in a high temperature environment is suppressed. Moreover, the said polymer (A) obtained also ensures alkali resistance by including the monomer component which does not have a carboxyl group called a styrene-type monomer and a (meth) acrylic acid ester-type monomer.

The carboxylic acid having a carbon-carbon double bond is not particularly limited as long as it has a carbon-carbon double bond and can be copolymerized, but the following general formula (2)
R ⁴ — (— COOH) _m (2)
(R ⁴ represents an organic group having 2 to 20 carbon atoms having a (meth) acryloyl group or a vinyl group, and may contain an oxygen atom. M represents an integer of 1 to 3)
It is preferable that it is carboxylic acid represented by (meth) acrylic acid or following General formula (3)

(R ⁵ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R ⁶ represents an alkylene group having 1 to 5 carbon atoms or a divalent organic group having 4 to 20 carbon atoms having a cyclic structure. R ⁶ may contain an oxygen atom.)
It is a carboxylic acid represented by More specifically, examples of the carboxylic acid represented by the general formula (3) include those in which R ⁶ has a group obtained by removing two hydrogen atoms from cyclohexane, norbornane, tricyclodecane, and tetracyclododecane. be able to.

  The said carboxylic acid which has a carbon-carbon double bond may be used independently, and may be used in combination of 2 or more types. Among them, the carboxylic acid having a carbon-carbon double bond is more preferably (meth) acrylic acid. The copolymerization of the carboxylic acid having a carbon-carbon double bond, the styrene monomer, and the (meth) acrylic acid ester monomer proceeds suitably, and the resulting polymer structure is more stable. It becomes. Therefore, dissociation between molecular chains can be prevented, and heat resistance and adhesive strength in a high temperature environment are improved.

  The amount of the carboxylic acid having a carbon-carbon double bond may be appropriately set according to the properties of the target adhesive composition such as adhesive strength, but is 10% relative to the total amount of all monomer components. It is preferably less than mass%, more preferably 1 mass% or more and less than 5 mass%. When the amount of the carboxylic acid having a carbon-carbon double bond is 1% by mass or more based on the total amount of all monomer components, the heat resistance of the resulting adhesive composition and the adhesive strength in a high temperature environment Can be further improved. Moreover, if the usage-amount of the carboxylic acid which has the said carbon-carbon double bond is less than 10 mass% with respect to the total amount of all the monomer components, the hygroscopic property of adhesive composition will be suppressed and gelatinization will be carried out. In addition to being able to prevent, alkali resistance can also be improved by reducing the quantity of the carboxyl group which the said adhesive composition has.

  The timing for mixing the carboxylic acid having the carbon-carbon double bond is not particularly limited as long as the carboxylic acid having the carbon-carbon double bond can be copolymerized.

  That is, the carboxylic acid having the carbon-carbon double bond may be mixed in advance with a monomer other than the carboxylic acid having the carbon-carbon double bond before starting the copolymerization reaction. And after starting the copolymerization reaction of monomers other than the carboxylic acid which has the said carbon-carbon double bond, you may mix before the said copolymerization reaction is complete | finished.

  However, it is more preferable to start the copolymerization reaction after previously mixing the carboxylic acid having the carbon-carbon double bond and the monomer other than the carboxylic acid having the carbon-carbon double bond. A carboxylic acid having a carbon-carbon double bond other than a carboxylic acid having a carbon-carbon double bond is obtained by copolymerizing a monomer mixed with the carboxylic acid having a carbon-carbon double bond in advance. Random copolymerization with the ingredients. Therefore, the polar group is present uniformly in the adhesive composition, and the polarity of the adhesive composition at the interface between the adhesive composition and the adherend is further improved, and the adhesive composition in a high-temperature environment. It is considered that the bond strength is further improved because the dissociation between the molecular chains inside is further suppressed.

(Bifunctional monomer)
In the adhesive composition obtained by using a bifunctional monomer as the other monomer component, the constituent molecules are cross-linked through the bifunctional monomer. By this crosslinking, the obtained adhesive composition has a three-dimensional structure, and the mass average molecular weight of the adhesive composition is increased. In general, in the technical field of adhesives, it is known that the internal energy of an adhesive composition increases when the mass average molecular weight of the constituent molecules increases. This internal energy is also known to be one factor that determines the level of adhesive strength in a high temperature environment. Moreover, when the mass average molecular weight of the adhesive composition is increased, the apparent glass transition point is also increased, thereby improving the adhesive strength.

  Further, by using a bifunctional monomer as the other monomer component, dissociation of molecular chains in the adhesive composition in a high temperature environment is suppressed. Thereby, the adhesive strength at high temperature is improved, and it can be easily peeled off from the adherend even after a high temperature process. Further, even when the above-described carboxylic acid having a carbon-carbon double bond is not used, effects such as improvement of heat resistance can be obtained, so that the alkali resistance of the adhesive composition can be further improved. .

  Therefore, by using a bifunctional monomer as the other monomer component, the heat resistance of the adhesive composition, the adhesive strength in a high temperature environment (especially 140 ° C. to 200 ° C.), and the peeling after the high temperature process are performed. Can be further improved.

The bifunctional monomer refers to a compound having two functional groups. That is, the bifunctional monomer is not particularly limited as long as it is a compound having two functional groups. For example, the following general formula (4)
X ¹ -R ⁷ -X ² (4)
(R ⁷ represents an alkylene group having 2 to 20 carbon atoms or a divalent organic group having 6 to 20 carbon atoms having a cyclic structure, and R ⁷ may contain an oxygen atom. X ¹ and X ² Each independently represents a (meth) acryloyl group or a vinyl group.
It is preferable that it is at least 1 compound chosen from the group which consists of a compound represented by these. More specifically, examples of the compound represented by the general formula (4) include dimethylol-tricyclodecane diacrylate, neopentyl glycol diacrylate, 1,9-nonanediol acrylate, naphthalene diacrylate, and the following formula ( 5)

(R ⁸ and R ⁹ each independently represent ethylene oxide or propylene oxide, and n and s are each independently an integer of 0 to 4.)
And the like. The above bifunctional monomers may be used alone or in combination of two or more.

  These bifunctional monomers are easily cross-linked with monomers other than the bifunctional monomer, and the cross-linked structure is stable. Therefore, by using the bifunctional monomer, it is possible to obtain an adhesive composition having further improved adhesive strength and heat resistance in a high temperature environment.

  The amount of the bifunctional monomer used may be appropriately set according to the properties of the target adhesive composition such as adhesive strength, but is less than 1% by mass with respect to the total amount of all monomer components. It is preferably 0.1% by mass or more and less than 0.5% by mass, and more preferably 0.1% by mass or more and less than 0.3% by mass. If the amount of the bifunctional monomer used is 0.1% by mass or more and less than 0.5% by mass, the adhesive strength and heat resistance of the obtained adhesive composition in a high temperature environment are further improved, and hygroscopicity is obtained. Therefore, gelation of the adhesive composition can be prevented.

  The bifunctional monomer is most preferably mixed in advance with a monomer component other than the bifunctional monomer before the start of the copolymerization reaction. However, a part or all of the bifunctional monomer is mixed. Even if they are mixed after the start of the copolymerization reaction of monomer components other than the bifunctional monomer, substantially the same effect can be obtained.

<Method for producing polymer (A)>
The method for producing the polymer (A) is a copolymerization of a monomer containing 60% by mass or more of a styrene monomer and a (meth) acrylic acid ester monomer with respect to the total amount of all monomer components. And it will not specifically limit if it is a method of obtaining the said polymer (A), A conventionally well-known method can be selected suitably and can be used. For example, the polymer (A) can be obtained by stirring the monomer using an existing stirring device.

  The temperature condition in the copolymerization reaction may be set as appropriate, and is not particularly limited, but is preferably 60 to 150 ° C, and more preferably 70 to 120 ° C.

  In the copolymerization reaction, a solvent may be appropriately used. Examples of the solvent include ketones such as acetone, methyl ethyl ketone, cyclohexanone, methyl isoamyl ketone, and 2-heptanone; ethylene glycol, ethylene glycol monoacetate, diethylene glycol, diethylene glycol monoacetate, propylene glycol, propylene glycol monoacetate, dipropylene glycol Or polyhydric alcohols such as monomethyl ether, monoethyl ether, monopropyl ether, monobutyl ether or monophenyl ether of dipropylene glycol monoacetate and derivatives thereof; cyclic ethers such as dioxane; and methyl lactate, ethyl lactate, acetic acid Methyl, ethyl acetate, butyl acetate, methyl pyruvate, ethyl pyruvate, methyl methoxypropionate, ethoxy Organic solvents esters such as propionic acid ethyl can be suitably used. These may be used alone or in combination of two or more.

  Among these solvents, ethylene glycol, ethylene glycol monoacetate, diethylene glycol, diethylene glycol monoacetate, propylene glycol, propylene glycol monoacetate, dipropylene glycol or dipropylene glycol monoacetate monomethyl ether, monoethyl ether, monopropyl ether, mono Polyhydric alcohols such as butyl ether or monophenyl ether and derivatives thereof are more preferable, and propylene glycol monomethyl ether acetate (hereinafter referred to as “PGMEA”) is more preferable.

  Moreover, in a copolymerization reaction, you may use a polymerization initiator suitably. As polymerization initiators, 2,2′-azobisisobutyronitrile, 2,2′-azobis (2-methylbutyronitrile), dimethyl 2,2′-azobisisobutyrate, 1,1′-azobis (cyclohexane) -1-carbonitrile), 4,4'-azobis (4-cyanovaleric acid) and other azo compounds; decanoyl peroxide, lauroyl peroxide, benzoyl peroxide, bis (3,5,5-trimethylhexanoyl) Such as peroxide, succinic peroxide, tert-butylperoxy-2-ethylhexanoate, tert-butylperoxypivalate, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, etc. Mention may be made of organic peroxides. These may be used alone or as a mixture of two or more thereof. The amount of the polymerization initiator used is not particularly limited as long as it is appropriately set according to the combination of the monomers and reaction conditions.

(I-2) Antioxidant The adhesive composition according to the present invention contains the polymer (A) as a main component and contains an antioxidant (B). In the adhesive composition according to the present invention, excellent alkaline overwater resistance can be achieved by containing the antioxidant (B).

  The antioxidant (B) used in the adhesive composition according to the present invention is not particularly limited as long as it is generally used as an antioxidant. For example, a hindered amine antioxidant is used. A hindered phenol-based antioxidant or the like can be preferably used.

  More specifically, examples of the antioxidant (B) include bis (1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate and 2- (3,5-di-t-butyl). Hindered amine antioxidants such as -4- (hydroxybenzyl) -2-n-butylmalonate bis (1,2,2,6,6-pentamethyl-4-piperidyl); 4,4-thiobis (6-t- Butyl-m-cresol), 3,9-bis [2- [3- (3-tert-butyl-4-hydroxy-5-methylphenyl) -propionyloxy] -1,1-dimethyl] -2,4 8,10-tetraoxaspiro (5.5) undecane, 2,2′-methylenebis (6-tert-butyl-4-methylphenol), 2,2′-methylenebis (6-tert-butyl-4-ethylphenol) ), 4,4'-Buchi Denbis (6-t-butyl-3-methylphenol), 4,4′-thiobis (6-t-butyl-3-methylphenol, alkylated bisphenol, 2,6-di-t-butyl-p-cresol, 2,6-di-tert-butyl-4-ethylphenol, 1,1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, n-octadecyl-3- (3,5 -Di-t-butyl-4-hydroxyphenyl) propionate, tetrakis [methylene-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] methane, triethylene glycol bis [3- (3- t-butyl-4-hydroxy-5-methylphenyl) propionate, tris (3,5-di-t-butyl-4-hydroxybenzyl) isocyanurate, etc. Can be exemplified hindered phenol antioxidant.

  Among these, the antioxidant (B) is 4,4′-thiobis (6-tert-butyl-m-cresol), 3,9-bis [2- [ 3- (3-t-butyl-4-hydroxy-5-methylphenyl) -propionyloxy] -1,1-dimethylethyl] -2,4,8,10-tetraoxaspiro (5,5) undecane etc. More preferably.

  The said antioxidant (B) may be used independently and may be used in combination of 2 or more types.

  The content of the antioxidant (B) contained in the adhesive composition according to the present invention is preferably 1% by mass or more and less than 30% by mass with respect to the polymer (A). More preferably, the content is less than 25% by mass, and more preferably 10% by mass or more and less than 20% by mass. When the content of the antioxidant (B) with respect to the polymer (A) is 1% by mass or more, the alkali overwater resistance of the adhesive composition can be improved. Moreover, it is preferable that the content of the antioxidant (B) with respect to the polymer (A) is less than 30% by mass because further improvement in alkaline overwater resistance is observed.

(I-3) Antioxidant auxiliary agent (C)
Moreover, the adhesive composition according to the present invention may contain the polymer (A) and the antioxidant (B), but in addition to these, further contains an antioxidant auxiliary agent (C). It is preferable. In the adhesive composition according to the present invention, the alkali overwater resistance can be further improved by further containing an antioxidant assistant (C).

  Here, as said antioxidant adjuvant (C), a phosphorus antioxidant, a sulfur type antioxidant, etc. can be used suitably, for example.

  More specifically, examples of the antioxidant assistant (C) include tris (2,4-di-t-butylphenyl) phosphite and tetrakis (2,4-di-t-butylphenyl) -4. , 4'-biphenylene phosphite, trisnonylphenyl phosphite, bis (2,4-di-t-butylphenyl) pentaerythritol diphosphite, distearyl pentaerythritol diphosphite, etc .; , 3-thiodipropionate, dimyristyl 3,3-thiodipropionate, distearyl 3,3-thiodipropionate, ditridecyl 3,3-thiodipropionate, pentaerythrityl tetrakis (3-laurylthiodipropio Nate, sulfur-based antioxidants such as 2-mercaptobenzimidazole It can gel.

  Among these, the antioxidant auxiliary agent (C) is more preferably a sulfur-based antioxidant auxiliary agent, more preferably a thioether-based antioxidant auxiliary agent, from the viewpoint of improving the alkali perwater resistance, and ditridecyl. Particularly preferred is 3,3-thiodipropionate.

  The said antioxidant adjuvant (C) may be used individually by 1 type, and may be used in combination of 2 or more type.

  The content of the antioxidant assistant (C) contained in the adhesive composition according to the present invention is preferably 5% by mass or more and less than 200% by mass with respect to the antioxidant (B). % Or more and less than 100% by mass, more preferably 10% by mass or more and less than 60% by mass. When the content of the antioxidant assistant (C) with respect to the antioxidant (B) is 5% by mass or more, the alkali overwater resistance of the adhesive composition can be further improved. Moreover, when the content of the antioxidant assistant (C) with respect to the antioxidant (B) is less than 200% by mass, further improvement in resistance to alkaline water is recognized, which is more preferable.

(I-4) Other components The adhesive composition according to the present invention may contain acrylamide such as dimethylacrylamide; and morpholine such as acryloylmorpholine as other components. Thereby, simultaneous improvement of heat resistance and adhesiveness can be expected.

  Further, the adhesive composition according to the present invention is a miscible additive, for example, an additional resin, a plasticizer, an adhesion aid for improving the performance of the adhesive, as long as the properties are not impaired. It may contain a stabilizer, a colorant, a surfactant and the like.

(II) Use of Adhesive Composition The adhesive composition according to the present invention can be used in various ways depending on the application. For example, the adhesive composition according to the present invention may be diluted with an organic solvent and applied onto a workpiece such as a semiconductor wafer to form an adhesive layer. Alternatively, an adhesive layer containing the adhesive composition of the present invention is formed in advance on a film such as a flexible film and then dried, and this film (adhesive film) is attached to a workpiece to be used. A method (adhesive film method) may be used.

  Therefore, the present invention also includes an adhesive film including an adhesive layer containing the adhesive composition according to the present invention on the film. The present invention also includes a liquid adhesive obtained by diluting the adhesive composition according to the present invention with an organic solvent.

(Adhesive film)
Since the adhesive film according to the present invention includes an adhesive layer containing the adhesive composition on the film, the adhesive film has alkali overwater resistance, heat resistance, adhesive strength in a high temperature environment, and alkali resistance. It is possible to obtain an adhesive film having an adhesive layer that has excellent peelability.

  When the polymer (A), which is the main component of the adhesive composition, contains a carboxylic acid having a carbon-carbon double bond as a monomer, a polar group is introduced into the adhesive layer. The Therefore, it is possible to obtain an adhesive film having an adhesive layer that has alkali water resistance, high heat resistance, high adhesive strength in a high temperature environment, and alkali resistance and can be easily peeled even after a high temperature process.

  Moreover, when the said polymer (A) contains the said bifunctional monomer as a monomer, the molecule | numerator which comprises the said adhesive bond layer is bridge | crosslinked by the said bifunctional monomer. When the polymer (A) contains the styrene macromonomer as a monomer, the average molecular weight of the adhesive composition constituting the adhesive layer is increased, and the adhesive layer is It has a styrene block structure derived from a styrene macromonomer. Thereby, dissociation of the molecular chains in the adhesive composition in a high temperature environment is further suppressed. Moreover, generation | occurrence | production of the gas in the interface of the said adhesive composition and the to-be-adhered surface where the said adhesive composition is apply | coated can be prevented.

  The adhesive film may be used by further covering the adhesive layer with a protective film. In this case, the protective film on the adhesive layer is peeled off, the exposed adhesive layer is stacked on the workpiece, and then the adhesive layer is formed on the workpiece by peeling the film from the adhesive layer. It can be easily provided.

  Therefore, if the above adhesive film is used, a layer with better film thickness uniformity and surface smoothness can be formed compared to the case where the adhesive composition is formed directly by applying the adhesive composition on the workpiece. can do.

  Moreover, as said film used for manufacture of the said adhesive film, the adhesive bond layer formed on the film can be peeled from a film, and an adhesive bond layer is transcribe | transferred on to-be-processed surfaces, such as a protective substrate and a wafer. It is not limited as long as it is a release film. For example, the flexible film which consists of synthetic resin films, such as a polyethylene terephthalate with a film thickness of 15-125 micrometers, polyethylene, a polypropylene, a polycarbonate, a polyvinyl chloride, is mentioned. If necessary, the film is preferably subjected to a release treatment so as to facilitate transfer.

  As a method for forming the adhesive layer on the film, a known method may be appropriately used according to the desired film thickness and uniformity of the adhesive layer, and is not limited. For example, an applicator, A method of applying the adhesive composition according to the present invention using a bar coater, a wire bar coater, a roll coater, a curtain flow coater or the like so that the dry film thickness of the adhesive layer is 10 to 1000 μm on the film. Is mentioned. Among these, a roll coater is preferable because it is excellent in film thickness uniformity and a thick film can be efficiently formed.

  Moreover, when using the said protective film, as said protective film, although not limited as long as it can peel from the said adhesive bond layer, a polyethylene terephthalate film, a polypropylene film, a polyethylene film is preferable, for example. Each of the protective films is preferably coated or baked with silicon. This is because peeling from the adhesive layer becomes easy. Although the thickness of the said protective film is not specifically limited, 15-125 micrometers is preferable. It is because the softness | flexibility of the said adhesive film provided with the protective film is securable.

  The method of using the adhesive film is not particularly limited. For example, when a protective film is used, the film is peeled off and the exposed adhesive layer is overlaid on the workpiece to form a film. A method of thermocompression bonding the adhesive layer to the surface of the workpiece by moving the heating roller from above (the back surface of the surface on which the adhesive layer is formed) can be mentioned. At this time, the protective film peeled off from the adhesive film can be stored and reused by winding it in a roll with a winding roller or the like.

(Liquid adhesive)
The adhesive composition according to the present invention may be diluted with an organic solvent for viscosity adjustment within a range that does not impair its properties. A liquid adhesive obtained by diluting the adhesive composition according to the present invention with an organic solvent can be directly applied to a workpiece to form an adhesive layer.

  Examples of the organic solvent include ketones such as acetone, methyl ethyl ketone, cyclohexanone, methyl isoamyl ketone, and 2-heptanone; ethylene glycol, ethylene glycol monoacetate, diethylene glycol, diethylene glycol monoacetate, propylene glycol, propylene glycol monoacetate, and dipropylene. Polyhydric alcohols such as glycol or dipropylene glycol monoacetate monomethyl ether, monoethyl ether, monopropyl ether, monobutyl ether or monophenyl ether and derivatives thereof; cyclic ethers such as dioxane; and methyl lactate, ethyl lactate, Methyl acetate, ethyl acetate, butyl acetate, methyl pyruvate, ethyl pyruvate, methyl methoxypropionate, etho It can be mentioned esters such Shipuropion ethyl. These may be used alone or in combination of two or more. In particular, ethylene glycol, ethylene glycol monoacetate, diethylene glycol, diethylene glycol monoacetate, propylene glycol, propylene glycol monoacetate, dipropylene glycol or dipropylene glycol monoacetate monomethyl ether, monoethyl ether, monopropyl ether, monobutyl ether or monophenyl Polyhydric alcohols such as ether and derivatives thereof are preferred.

  The amount of the organic solvent used is appropriately set according to the film thickness to which the adhesive composition is applied, and is particularly limited as long as the adhesive composition can be applied onto a support such as a semiconductor wafer. Is not to be done. Generally, it is used so that the solid content concentration of the adhesive composition is in the range of 20 to 70% by mass, preferably 25 to 60% by mass.

  The adhesive composition of the present embodiment is not particularly limited as long as it is used as an adhesive composition for bonding applications, but is used for bonding a semiconductor wafer precision processing protective substrate to a substrate such as a semiconductor wafer. It can be suitably used as an agent composition. The adhesive composition of the present invention can be suitably used as an adhesive composition for adhering the substrate to a support plate, particularly when grinding and thinning a substrate such as a semiconductor wafer (for example, JP, 2005-191550, A).

(III) Method for Producing Adhesive Composition The method for producing an adhesive composition according to the present invention mainly comprises a polymer (A) formed by copolymerizing a monomer containing styrene and a (meth) acrylic ester. It is not particularly limited as long as it is a method for producing an adhesive composition containing an antioxidant (B) as a component, and includes a mixing step of mixing the antioxidant (B) with the polymer (A). It only has to be included.

  In the mixing step, the method of mixing the antioxidant (B) with the polymer (A) is not particularly limited, and (a) the polymer (A) and the antioxidant (B) are mixed as they are. (B) a method in which the antioxidant (B) is added to the polymer (A) as a solution, aqueous solution or dispersion, and (c) an antioxidant in the solution, aqueous solution or dispersion of the polymer (A). A method of adding the agent (B), (d) a method of adding the antioxidant (B) as a solution, aqueous solution or dispersion to the solution, aqueous solution or dispersion of the polymer (A) may be appropriately selected. .

  When the polymer (A) is added as a solution, aqueous solution or dispersion, the solvent or dispersion medium to be used is more preferably the organic solvent described above, and the solid content concentration of the polymer (A) is 20 to 70% by mass. It is preferable and it is more preferable that it is 25-60 mass%.

  Moreover, what is necessary is just to remove a solvent or a dispersion medium after mixing by drying etc. as needed.

  When the adhesive composition further contains an antioxidant auxiliary agent (C) and / or other components, the mixing method is not particularly limited, and is the same as the mixing methods (a) to (d). What is necessary is just to mix using the method of.

  In this case, the order of mixing the polymer (A), the antioxidant (B), the antioxidant auxiliary agent (C) and / or other components is not particularly limited, and all the components are mixed simultaneously. You may mix, after mixing the said polymer (A) and antioxidant (B), you may mix antioxidant adjuvant (C) and / or another component, and the said polymer (A). After mixing the antioxidant with the antioxidant (C), the antioxidant (B) and other components as necessary may be mixed. Moreover, after mixing antioxidant (B) and antioxidant adjuvant (C) previously, you may mix with the said polymer (A).

  EXAMPLES Hereinafter, although this invention is demonstrated more concretely based on an Example and a comparative example, this invention is not limited to these.

  The adhesive composition of the present invention has an alkali overwater resistance, heat resistance, hygroscopicity, a gas generation amount at 200 ° C. (hereinafter referred to as “degassing” in the present specification), and flexibility. Was measured and evaluated.

(Alkaline overwater resistance)
<Evaluation method 1>
After applying an adhesive composition diluted with PGMEA on a 6-inch silicon wafer, it was dried at 110 ° C., 150 ° C., and 200 ° C. for 3 minutes each for 9 minutes in total, and on the silicon wafer, An adhesive layer having a thickness of 15 μm was formed. Next, the obtained adhesive layer together with a silicon wafer was mixed with ammonia perwater obtained by mixing 29% ammonia water, 30% hydrogen peroxide water and water in a volume ratio of 1: 1: 5 at 70 ° C. It was immersed for a minute, and the presence or absence of peeling of the adhesive layer from the silicon wafer was visually observed. The case where peeling of the adhesive layer was not confirmed by visual observation was indicated as “◯”, and the case where the adhesive layer was confirmed was indicated as “X”.

<Evaluation method 2>
After applying an adhesive composition diluted with PGMEA on a 6-inch silicon wafer, it was dried at 110 ° C., 150 ° C., and 200 ° C. for 3 minutes each for 9 minutes in total, and on the silicon wafer, An adhesive layer precursor having a film thickness of 15 μm was formed. Next, a 6-inch glass substrate having a circular hole having a diameter of 500 μm was bonded to the obtained adhesive layer precursor at 200 ° C. under a load of 5 kg / mm ² over 5 minutes. The obtained laminate of the silicon wafer, the adhesive layer, and the glass substrate was mixed with 29% ammonia water, 30% hydrogen peroxide solution, and water at a volume ratio of 1: 1: 5. It was immersed in water at 70 ° C. for 10 minutes, and the presence or absence of cracks in the adhesive layer was visually observed. The case where no crack of the adhesive layer was confirmed by visual observation was designated as “◯”, and the case where the crack was confirmed was designated as “X”.

[Heat resistance, hygroscopicity, degassing]
After the adhesive composition diluted with PGMEA was applied onto a silicon wafer, it was dried at 110 ° C., 150 ° C., and 200 ° C. for 3 minutes for a total of 9 minutes, respectively, and the film thickness was 15 μm on the silicon wafer. The coating film was formed. Next, the formed coating film was heated from 40 ° C. to 250 ° C., the amount of degassing from the coating film was measured, and the heat resistance, hygroscopicity, and degassing were evaluated based on the degassing amount.

  The reason why the heat resistance and hygroscopicity can be evaluated based on the degassing amount is as follows. That is, the degassing amount measured up to 100 ° C. is derived from water vapor or its azeotropic gas. And since the said water vapor | steam or its azeotropic gas originates in the water | moisture content which the adhesive composition absorbed moisture, hygroscopicity can be evaluated by the degassing amount measured by 100 degreeC. Further, the degassing amount measured at 100 ° C. or higher is derived from a gas generated by the adhesive composition itself being decomposed by heat. Therefore, the heat resistance of the adhesive composition can be evaluated by the amount of degassing at 100 ° C. or higher, particularly around 200 ° C.

  The TDS method (Thermal Desorption Spectroscopy method, temperature programmed desorption analysis method) was used for the measurement of the degassing amount. An EMD-WA1000 manufactured by Electronic Science Co., Ltd. was used as the TDS measurement device (release gas measurement device).

  The measurement conditions of the TDS measuring apparatus were Width: 100, Center Mass Number: 50, Gain: 9, Scan Speed: 4, and Ultra Volt: 1.3 KV.

  The evaluation of heat resistance is “◯” when the strength (Intensity) required by the above TDS measuring apparatus is less than 100,000 at 200 ° C. and the residue is not observed with a metal microscope, and is 100,000 or more. In the case where the residue is not observed with “Δ”, it is 100,000 or more, and when the residue is observed with a metal microscope, it is indicated as “×”.

  In the evaluation of hygroscopicity, “◯” was given when the intensity at 100 ° C. was less than 10,000, and “x” was given when it was 10,000 or more.

  The evaluation of degassing was “◯” when the intensity (Intensity) required by the TDS measuring apparatus was less than 100,000 at 200 ° C., and “X” when it was 100,000 or more.

[Flexibility]
An adhesive composition diluted with PGMEA using a spinner on a 6-inch silicon wafer was applied at 1000 rpm for 25 seconds and then heated on a hot plate at 200 ° C. for 3 minutes to form an adhesive layer on the silicon wafer. Formed. Next, the presence or absence of cracks in the obtained adhesive layer was visually observed. The silicon wafer used had a thickness of 15 μm.

[Reference example]
The main component of the adhesive composition according to the present invention, that is, a polymer (A) obtained by copolymerizing a monomer containing a styrene monomer and a (meth) acrylate monomer was produced. .

In a 300 ml four-necked flask equipped with a reflux condenser, a stirrer, a thermometer, and a nitrogen inlet tube, 111.6 g of PGMEA as a solvent and 27 g of methyl methacrylate as a monomer monomer as shown in Table 1 Then, 52 g of styrene, 3 g of phenoxyethyl acrylate, 18 g of isobornyl methacrylate, and 5 g of acrylic acid were charged, and N ₂ blowing was started. Polymerization is started by starting stirring, and the temperature is raised to 100 ° C. while stirring. Then, a mixed solution consisting of 13.33 g of PGMEA and 1 g of t-butylperoxy 2-ethylhexanoate (polymerization initiator) is added to the dropping nozzle. Then, it was dripped continuously over 4 hours. The dropping speed was constant.

  The polymerization reaction liquid obtained after completion of the dropwise addition was aged at 100 ° C. for 1 hour as it was, and then a mixed liquid consisting of 25.10 g of PGMEA and 0.3 g of t-butylperoxy 2-ethylhexanoate was dropped over 1 hour. did. Thereafter, the polymerization reaction liquid was further aged for 1 hour at 100 ° C., and then 1.0 g of 1,1,3,3-tetramethylbutylperoxy 2-ethylhexanoate was added all at once. Next, after aging the polymerization reaction solution for 3 hours at 100 ° C., the polymerization reaction solution was heated until the reflux of the solvent was observed, and then aged for 1 hour to complete the polymerization and synthesize resin 1.

  The weight average molecular weight of the obtained resin 1 was 97000. The weight average molecular weight is a standard polystyrene equivalent mass average molecular weight determined by GPC.

[Example 1]
As a polymer (A) obtained by copolymerizing a monomer containing a styrene monomer and a (meth) acrylic acid ester monomer, 100 g of the resin 1 obtained in the above Reference Example, and antioxidant As an agent (B), 20 g of 4,4-thiobis (6-t-butyl-m-cresol) was dissolved in PGMEA to obtain a PGMEA solution of an adhesive composition having a resin 1 concentration of 40% by mass.

  Table 1 shows the results of evaluating the alkali water resistance, heat resistance, hygroscopicity, degassing, and flexibility of the adhesive layer formed using the PGMEA solution of the obtained adhesive composition.

  Moreover, the result of the evaluation method 1 of alkaline water resistance is shown in FIG. 1 (b), and the result of the evaluation method 2 is shown in FIG. 2 (e). As shown in FIG. 1B, in the adhesive composition containing the polymer (A) and 4,4-thiobis (6-t-butyl-m-cresol), the peeling of the adhesive layer from the silicon wafer is It was not confirmed. Moreover, as shown in FIG.2 (e), the crack of the adhesive bond layer was not confirmed.

[Example 2]
As a polymer (A) obtained by copolymerizing a monomer containing a styrene monomer and a (meth) acrylic acid ester monomer, 100 g of the resin 1 obtained in the above Reference Example, and antioxidant As the agent (B), 3,9-bis (2- (3- (3-t-butyl-4-hydroxy-5-methylphenyl) -propionyloxy) -1,1-dimethylethyl) -2,4, 8 g of 10-tetraoxaspiro (5,5) undecane and 7 g of ditridecyl-3,3′-thiodipropionate as an antioxidant assistant (C) were mixed and dissolved in PGMEA. A PGMEA solution of an adhesive composition having a concentration of 40% by mass was obtained.

  Table 1 shows the results of evaluating the alkali water resistance, heat resistance, hygroscopicity, degassing, and flexibility of the adhesive layer formed using the PGMEA solution of the obtained adhesive composition.

  Moreover, the result of the evaluation method 1 of alkali overwater tolerance is shown in FIG.1 (c), and the result of the evaluation method 2 is shown in FIG.2 (f). As shown in FIG. 1 (c), the polymer (A) and 3,9-bis (2- (3- (3-t-butyl-4-hydroxy-5-methylphenyl) -propionyloxy) -1,1 -Dimethyl) -2,4,8,10-tetraoxaspiro (5,5) undecane 13g and ditridecyl-3,3'-thiodipropionate 7g, an adhesive from a silicon wafer No peeling of the layer was confirmed. Further, the surface of the adhesive layer was smoother than that in Example 1. Moreover, as shown in FIG.2 (f), the crack of the adhesive bond layer was not confirmed.

[Comparative example]
Alkaline water resistance of an adhesive layer formed using a PGMEA solution of an adhesive composition having a concentration of resin 1 obtained by dissolving 100 g of resin 1 obtained in the above Reference Example in PGMEA, Table 1 shows the results of evaluation of heat resistance, hygroscopicity, degassing, and flexibility.

  Moreover, the result of the evaluation method 1 of alkali overwater tolerance is shown to Fig.1 (a), and the result of the evaluation method 2 is shown to FIG.2 (d). As shown to Fig.1 (a), peeling of the adhesive bond layer from a silicon wafer was confirmed in the adhesive composition which contains a polymer (A) as a main component, but does not contain antioxidant (B). Moreover, as shown in FIG.2 (d), the crack of the adhesive bond layer was confirmed.

  From the results shown in Table 1, an adhesive composition mainly composed of a polymer (A) obtained by copolymerizing a monomer containing a styrene monomer and a (meth) acrylate monomer is When the antioxidant (B) is contained, it can be seen that the heat resistance, hygroscopicity, degassing, and flexibility performance are maintained, and the alkali overwater resistance is remarkably improved.

  The adhesive composition according to the present invention, an adhesive film using the same, a liquid adhesive, and the like have resistance to alkali water, high heat resistance and alkali resistance, low hygroscopicity, and gas generated during heating. There are few, and peeling with a peeling liquid can be performed easily. Therefore, it can be suitably used for a semiconductor wafer or chip processing step that undergoes a process using various chemicals such as a high-temperature process, a high-vacuum process, and alkaline hydrogenation.

In the Example of this invention, it is a figure which shows the result of having evaluated the alkali overwater tolerance of an adhesive composition. In the Example of this invention, it is a figure which shows the result of having evaluated the alkali overwater tolerance of an adhesive composition.

Claims (11)

An adhesive composition mainly comprising a polymer (A) obtained by copolymerizing a monomer containing a styrene monomer and a (meth) acrylic acid ester monomer,
An adhesive composition comprising an antioxidant (B).   The adhesive composition according to claim 1, wherein the antioxidant (B) is a hindered amine-based antioxidant and / or a hindered phenol-based antioxidant.   Content of the said antioxidant (B) is 1 mass% or more and less than 30 mass% with respect to the said polymer (A), The adhesive composition of Claim 1 or 2 characterized by the above-mentioned. The antioxidant (B) is
4,4-thiobis (6-tert-butyl-m-cresol) and 3,9-bis [2- [3- (3-tert-butyl-4-hydroxy-5-methylphenyl) -propionyloxy] It is at least one of -1,1-dimethyl] -2,4,8,10-tetraoxaspiro (5,5) undecane. Adhesive composition.   The (meth) acrylic acid ester-based monomer includes a (meth) acrylic acid ester having a cyclic structure and a (meth) acrylic acid ester having a chain structure. The adhesive composition according to any one of the above.   The adhesive composition according to any one of claims 1 to 5, further comprising an antioxidant auxiliary agent (C).   The adhesive composition according to claim 6, wherein the antioxidant auxiliary agent (C) is a phosphorus-based antioxidant and / or a sulfur-based antioxidant.   The adhesive according to claim 6 or 7, wherein the content of the antioxidant assistant (C) is 5% by mass or more and less than 200% by mass with respect to the antioxidant (B). Composition. The antioxidant aid (C) is
It is ditridecyl-3,3'-thiodipropionate, The adhesive composition of any one of Claims 6-8 characterized by the above-mentioned.   An adhesive film comprising an adhesive layer containing the adhesive composition according to any one of claims 1 to 9 on the film. A method for producing an adhesive composition mainly comprising a polymer (A) obtained by copolymerizing a monomer containing a styrene monomer and a (meth) acrylic acid ester monomer,
The manufacturing method of the adhesive composition which has the alkali overwater tolerance characterized by including the mixing process which mixes antioxidant (B) with the said polymer (A).