JP2011173956A - Adhesive composition and adhesive film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an adhesive composition that comprises a polymer obtained by polymerizing a monomer composition containing a styrene-based monomer and has at least any of raised glass transition point and softening point, preferably both raised glass transition point and softening point. <P>SOLUTION: The adhesive composition comprises a polymer as a main component obtained by polymerizing a monomer composition containing (meth)acrylic acid to which an adamantyl group is introduced and p-hydroxystyrene. The adhesive film is furnished with an adhesive layer containing the adhesive composition. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an adhesive composition and an adhesive film. More specifically, the present invention relates to an adhesive composition and an adhesive film for temporarily fixing a sheet or a protective substrate to a semiconductor product such as a semiconductor wafer in a process of grinding or the like for a semiconductor product such as a semiconductor wafer. Is.

  In recent years, with the enhancement of functions of mobile phones, digital AV devices, IC cards, and the like, demands for miniaturization, thinning, and high integration of semiconductor silicon chips (hereinafter referred to as chips) are increasing. 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 improves 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 surface of the wafer, 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.

  During dicing, a protective sheet is attached to the back side of the semiconductor wafer, the dicing is performed with the semiconductor wafer adhered and fixed, and the resulting chip is picked up by a needle from the film base and picked up and fixed on the die pad. ing.

  Examples of such processing adhesive films and protective sheets include adhesive compositions for 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).

  Here, what contains the polymer formed by superposing | polymerizing the monomer composition containing a styrene-type monomer as an adhesive composition is known (patent document 7, patent document 8).

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) Japanese Unexamined Patent Publication No. 64-1782 (published January 16, 1988) JP 2001-55404 A (published February 27, 2001)

  However, the above-mentioned pressure-sensitive adhesive film for processing or the like is used for a process requiring a high-temperature process and a high-vacuum process, such as the formation of a through electrode, and the adhesive strength is insufficient in a high-temperature environment, There is a problem of adhesion failure due to generation of gas, etc., and a problem of peeling failure such as residue remaining at the time of peeling after the high temperature process.

  For example, in the formation of the through electrode, when bumps are formed on the semiconductor chips and then the semiconductor chips are connected, a process of heating to about 200 ° C. and further making a high vacuum state is required. However, the adhesive composition constituting the adhesive layer of the protective tape according to Patent Document 1 and Patent Document 2 has no resistance to high temperatures of 200 ° C. Moreover, since gas is generated in the adhesive layer by heating, adhesion failure occurs.

  Further, a thin semiconductor wafer needs to be peeled off from the protective substrate after grinding or dicing. However, the adhesive composition constituting the adhesive layer of the protective tape disclosed in Patent Document 3 is an epoxy resin composition, and the epoxy resin is altered and cured at a high temperature of 200 ° C. There is a problem that a residue remains and peeling failure occurs.

  Furthermore, in the thermoplastic film used for adhesion | attachment of a protective substrate and a semiconductor wafer based on the said patent document 4 or the said patent document 5, since the gas derived from the moisture which absorbed moisture is produced, the problem of adhesion failure arises. In the method for processing a semiconductor substrate according to Patent Document 6, a mirror surface process using an etching solution or a metal film formation by vacuum deposition is performed. Therefore, an adhesive composition for bonding a protective substrate and a semiconductor wafer has a heat resistance. And releasability are required. However, the above Patent Document 6 does not disclose the composition of the adhesive composition at all.

  Further, depending on the desired processing, the glass point transition point and the softening point of the adhesive composition may be required to be higher than predetermined values.

  Here, since styrene does not deteriorate even in a high temperature environment of 200 ° C. or higher, it may be possible to impart heat resistance to the adhesive composition by using a styrene monomer. However, it has been very difficult to greatly increase the glass transition point and the softening point of the adhesive composition using the styrene monomer. Therefore, an adhesive for sticking a processing adhesive film or the like to a semiconductor wafer if at least one of the glass point transition point and the softening point, preferably both, of the adhesive composition using the styrene monomer can be increased. Since it can be used suitably as a composition, it is very useful.

  The present invention has been made in view of the above problems, and includes at least one of a glass transition point and a softening point including a polymer obtained by polymerizing a monomer composition containing a styrene monomer, preferably The main objective is to provide an adhesive composition in which both are elevated.

  The adhesive composition according to the present invention is obtained by polymerizing a monomer composition containing (meth) acrylic acid having an adamantyl group introduced therein and hydroxystyrene in order to solve the above problems. It is characterized by having a polymer as a main component.

  As described above, the adhesive composition according to the present invention is mainly composed of a polymer obtained by polymerizing a monomer composition containing (meth) acrylic acid having an adamantyl group introduced therein and hydroxystyrene. And Thus, an adhesive composition containing a polymer obtained by polymerizing a monomer composition containing a styrene monomer and having an elevated glass transition point and / or softening point is provided. Can do.

FIG. 1 is a graph showing measurement results of glass transition point and softening point by TMA.

[1: Adhesive composition]
One embodiment of the adhesive composition according to the present invention will be described below.

  The adhesive composition according to the present invention is an adhesive composition mainly composed of a polymer obtained by polymerizing a monomer composition containing (meth) acrylic acid having an adamantyl group introduced therein and hydroxystyrene. It is a thing.

  If the adhesive composition of this invention is used for the use as an adhesive agent, the specific use will not be specifically limited.

  In the present specification, the “main component” means that the content is higher than that of any other component contained in the adhesive composition of the present invention. Therefore, the content of the main component is not limited as long as it is the largest amount among the components contained in the adhesive composition, but is preferably the main component content with respect to the total amount of the adhesive composition. The component content is preferably 50% by mass or more and 100% by mass or less, and more preferably 70% by mass or more and 100% by mass or less. If it is 50 mass% or more, the effect regarding the dissolution rate with respect to the solvent with which the adhesive composition of this invention is equipped will be exhibited favorably.

((Meth) acrylic acid with an adamantyl group introduced)
The adhesive composition according to the present embodiment includes (meth) acrylic acid having an adamantyl group introduced into the monomer composition. The adamantyl group has a bulky and unique steric structure, and the monomer composition contains (meth) acrylic acid having an adamantyl group introduced therein, so that the glass transition point of the adhesive composition and At least one of the softening points, preferably both rise.

  Examples of (meth) acrylic acid into which the adamantyl group contained in the monomer composition according to the present embodiment is introduced include 1-adamantyl (meth) acrylate, 2-adamantyl (meth) acrylate, and 2-methyl. It is selected from the group consisting of 2-adamantyl (meth) acrylate, 2-ethyl-2-adamantyl (meth) acrylate, 2-isopropyl-2-adamantyl (meth) acrylate, and 3-hydroxy-1-adamantyl (meth) acrylate It can be a compound.

  The mixing amount of (meth) acrylic acid having an adamantyl group introduced is not particularly limited, and the effect is considered to increase as the mixing amount increases, but it is 5% by mass or more and 80% by mass of the total amount of the monomer composition. More preferably, it is 10 mass% or more and 70 mass% or less, More preferably, it is 10 mass% or more and 50 mass% or less. If it is in said range, the adhesive composition which at least any one of the glass transition point and the softening point, Preferably both raised can be obtained.

(P-hydroxystyrene)
The adhesive composition according to the present embodiment further includes hydroxystyrene in the monomer composition. By further including hydroxystyrene in the monomer composition, the glass transition point of the adhesive composition is improved, so that the fluidity at high temperature is increased and heat resistance can be imparted. The position of the hydroxyl group is not particularly limited, and may be any of o-position, m-position and p-position, but p-position is preferred. The amount of hydroxystyrene mixed is not limited as long as the copolymerization reaction proceeds with other compounds contained in the monomer composition, and the properties of the adhesive composition such as the desired adhesive strength and heat resistance are not limited. Accordingly, it may be appropriately determined, but it is more preferably 5% by mass or more and 80% by mass or less of the total amount of the monomer composition, and more preferably 5% by mass or more and 60% by mass or less, It is particularly preferably 5% by mass or more and 40% by mass or less, and most preferably 10% by mass or more and 25% by mass or less. If the mixing amount of p-hydroxystyrene is 5% by mass or more, an adhesive composition having a further improved glass transition point can be obtained, and if it is 80% by mass or less, good solubility can be obtained. it can.

((Meth) acrylic acid alkyl ester)
The adhesive composition according to the present embodiment may further include other (meth) acrylic acid alkyl esters in addition to (meth) acrylic acid having an adamantyl group introduced into the monomer composition.

  In this specification, (meth) acrylic acid alkyl ester means an acrylic long-chain alkyl ester having an alkyl group having 15 to 20 carbon atoms and an acrylic alkyl ester having an alkyl group having 1 to 14 carbon atoms.

  By including the (meth) acrylic acid alkyl ester in the monomer composition, the content of the alkyl chain contained in the polymer that is the main component of the adhesive composition is increased. Thereby, stress relaxation can be caused in the adhesive composition, and as a result, the occurrence of cracks can be suppressed while maintaining high temperature resistance. Further, by suppressing the generation of cracks, it is possible to suppress the intrusion of solvent from the cracks and the generation of dust. Thereby, process defects are reduced and the yield in the process is improved.

  As acrylic long-chain alkyl esters, the alkyl group is an acrylic acid or methacrylic acid whose n-pentadecyl group, n-hexadecyl group, n-heptadecyl group, n-octadecyl group, n-nonadecyl group, n-eicosyl group, etc. Examples include alkyl esters. In addition, the alkyl group of the acrylic long-chain alkyl ester may be linear or may have a branched chain.

  Examples of the acrylic alkyl ester having an alkyl group having 1 to 14 carbon atoms include known esters used in conventional (meth) acrylic adhesives. For example, acrylic acid or methacrylic acid in which the alkyl group is a methyl group, ethyl group, propyl group, butyl group, 2-ethylhexyl group, isooctyl group, isononyl group, isodecyl group, dodecyl group, tridecyl group, lauryl group, tridecyl group, etc. Mention may be made of alkyl esters of acids.

  In addition, when (meth) acrylic-acid alkylester is included in a monomer composition, the (meth) acrylic-acid alkylester which comprises the polymer which is a main component of an adhesive composition may use only 1 type. It is also possible to use a mixture of two or more.

  When the (meth) acrylic acid alkyl ester is included in the monomer composition, the mixing amount of the (meth) acrylic acid alkyl ester is as long as the copolymerization reaction proceeds with other compounds contained in the monomer composition. It is not limited, and may be appropriately determined according to the properties of the adhesive composition such as the intended adhesive strength and heat resistance. However, (meth) acrylic acid introduced with an adamantyl group is excluded (meta ) The total mixing amount of the alkyl acrylate ester is more preferably 5% by mass or more and 80% by mass or less of the total amount of the monomer composition, and more preferably 10% by mass or more and 60% by mass or less. Most preferably, it is 10 mass% or more and 40 mass% or less. If it is 5 parts by mass or more, it is possible to obtain an adhesive with improved flexibility and crack resistance, and if it is 80 parts by mass or less, adhesion with reduced heat resistance, poor peeling, and moisture absorption is suppressed. An agent can be obtained.

(styrene)
The adhesive composition according to the present embodiment may further contain styrene into which no substituent is introduced in the monomer composition. Since styrene into which a substituent is not introduced does not deteriorate even under a high temperature environment of 200 ° C. or higher, the heat resistance of the adhesive composition is further improved by including this.

  When the monomer composition contains styrene having no substituent introduced, the amount of styrene not having a substituent introduced is 5 mass% or more and 90 mass% or less of the total amount of the monomer composition. It is more preferable that it is 10 mass% or more and 80 mass% or less, and it is especially preferable that it is 20 mass% or more and 70 mass% or less. If the amount of styrene to which no substituent is introduced is within the above range, the adhesive composition has good heat resistance and heat-soluble solubility, and is preferable because it hardly generates gas.

  In addition to p-hydroxystyrene, the adhesive composition according to the present embodiment may further include styrene introduced with other substituents in addition to p-hydroxystyrene. For example, the adhesive composition according to the present embodiment may further include styrene having an alkyl group or an alkoxy group introduced into the monomer composition. By using styrene introduced with an alkyl group or an alkoxy group, the dissolution rate of the adhesive composition in the solvent can be improved.

  When the monomer composition contains styrene introduced with an alkyl group or alkoxy group, the mixing amount of styrene introduced with an alkyl group or alkoxy group is the same as that of other compounds contained in the monomer composition. As long as the polymerization reaction proceeds, it is not limited, and may be appropriately determined according to the properties of the adhesive composition such as target adhesive strength and heat resistance, but 10 mass of the total amount of the monomer composition. % Or more and 90% by mass or less, more preferably 20% by mass or more and 80% by mass or less, and particularly preferably 40% by mass or more and 80% by mass or less. When the amount of styrene introduced with an alkyl group or alkoxy group is within the above range, an adhesive composition having a further improved dissolution rate in a solvent can be obtained.

  The alkyl group introduced into the styrene is more preferably an alkyl group having 1 to 20 carbon atoms. For example, tert-butyl group, isobutyl group, tert-pentyl group, n-pentyl group, isopentyl group, n- An alkyl group selected from the group consisting of hexyl group, lauryl group, stearyl group, 2-ethylhexyl group, n-octyl group, isooctyl group, n-nonyl group, isononyl group, n-decyl group and isodecyl group is preferably used. Can do.

  The alkyl group may be introduced at the para-position of the styrene, may be introduced at the meta-position, may be introduced at the ortho-position, or may be a combination thereof. More preferably, it is introduced in

  The alkoxy group introduced into the styrene is more preferably an alkoxy group having 1 to 20 carbon atoms, for example, tert-butoxy group, isobutoxy group, tert-pentyloxy group, n-pentyloxy group, isopentyloxy. Group, n-hexyloxy group, lauryloxy group, stearyloxy group, 2-ethylhexyloxy group, n-octyloxy group, isooctyloxy group, n-nonyloxy group, isononyloxy group, n-decyloxy group or isodecyl An alkoxy group selected from the group consisting of oxy groups can be suitably used.

  The alkoxy group may be introduced at the para-position of the styrene, may be introduced at the meta-position, may be introduced at the ortho-position, or a combination thereof, More preferably, it is introduced in

(Styrene block segment)
Moreover, the polymer which is the main component of the adhesive composition according to this embodiment may have a styrene block segment.

  The adhesive composition mainly composed of a polymer having a styrene block segment can prevent gas generation at the interface between the adhesive composition and the adherend. Therefore, it is possible to obtain an adhesive composition having improved adhesive strength in a high temperature environment by preventing delamination of the adhesive composition due to gas generation at the interface during heating and vacuum.

  Moreover, since dissociation of the molecular chains in the adhesive composition in a high temperature environment is suppressed, alteration of the adhesive composition in a high temperature environment can be prevented. Therefore, the adhesive strength is improved, and further, it can be easily peeled even after a high temperature process.

  Further, by blocking styrene, a pseudo sea-island structure is formed in the coating film of the adhesive composition, and a relatively hard region and a relatively soft region are generated. This can cause stress relaxation due to heat. As a result, the occurrence of cracks can be suppressed while maintaining the high temperature resistance of the adhesive composition. Further, by suppressing the generation of cracks, it is possible to suppress the intrusion of solvent from the cracks and the generation of dust. Thereby, process defects are reduced and the yield in the process is improved.

  As used herein, “styrene block segment” refers to a site where styrene is copolymerized in block units in a polymer. Here, when styrene is added after the polymerization is started, the copolymerization of other components is almost completed, so that a block body made of only styrene is formed. Therefore, it can be said that the styrene block segment is a block copolymer obtained by polymerizing only styrene added after the polymerization of other monomer components is started.

  The styrene block segment is formed with styrene by mixing all or a part of the styrene with the remainder of the styrene and other monomer components to start the copolymerization reaction, and then before ending the copolymerization reaction. It is carried out by mixing in batches or in several batches to a copolymerization reaction system, that is, a reactor in which a copolymerization reaction is carried out.

  The amount of styrene forming the styrene block segment is adjusted by the amount of styrene added after the copolymerization reaction has been initiated. And the amount may be set as appropriate according to the properties of the adhesive composition such as the desired adhesive strength, heat resistance, etc., but the total amount of styrene used in the production of the adhesive composition according to the present embodiment When it is 100 parts by mass, it is preferably 1 part by mass or more and 100 parts by mass or less.

  Furthermore, it is preferable that styrene added after the copolymerization reaction is started is added all at once, that is, all the styrene is added 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 an adhesive composition because styrene crowds and copolymerizes.

(Ingredients other than the main component in the adhesive composition)
The adhesive composition according to the present embodiment may contain a thermal polymerization inhibitor, acrylamide such as dimethylacrylamide, morpholine such as acryloylmorpholine, and the like as other additive components. With these formulations, simultaneous improvement in heat resistance and adhesiveness can be expected.

  Here, the thermal polymerization inhibitor will be described below.

(Thermal polymerization inhibitor)
The thermal polymerization inhibitor is a substance effective for preventing radical polymerization reaction due to heat. Thermal polymerization inhibitors are highly reactive with radicals and react preferentially over monomers, so that polymerization is prohibited. Therefore, the adhesive composition containing the thermal polymerization inhibitor suppresses the polymerization reaction of the adhesive composition under a high temperature environment (particularly 250 ° C. to 350 ° C.). Thereby, even if it passes through the high temperature process heated at 250 degreeC for 1 hour, an adhesive composition can be melt | dissolved easily. Therefore, the adhesive layer formed by the adhesive composition can be easily peeled even after a high temperature process, and the generation of residues can be suppressed.

  The thermal polymerization inhibitor is not particularly limited as long as it is effective for preventing a radical polymerization reaction due to heat, but a phenol-based thermal polymerization inhibitor is more preferable.

  Examples of the thermal polymerization inhibitor include pyrogallol, benzoquinone, hydroquinone, methylene blue, tert-butylcatechol, monobenzyl ether, methylhydroquinone, amylquinone, amyloxyhydroquinone, n-butylphenol, phenol, hydroquinone monopropyl ether, 4,4′- (1-methylethylidene) bis (2-methylphenol), 4,4 ′-(1-methylethylidene) bis (2,6-dimethylphenol), 4,4 ′-[1- [4- (1- ( 4-hydroxyphenyl) -1-methylethyl) phenyl] ethylidene] bisphenol, 4,4 ′, 4 ″ -ethylidenetris (2-methylphenol), 4,4 ′, 4 ″ -ethylidenetrisphenol, 1,1, 3-Tris (2,5-dimethyl-4-hydroxyphen ) -3-phenylpropane, 2,6-di-tert-butyl-4-methylphenol, 2,2'-methylenebis (4-methyl-6-tertbutylphenol), 4,4'-butylidenebis (3-methyl) -6-tertbutylphenol), 4,4'-thiobis (3-methyl-6-tertbutylphenol), 3,9-bis [2- (3- (3-tertbutyl-4-hydroxy-5-methylphenyl) -Propionyloxy) -1,1-dimethylethyl] -2,4,8,10-tetraoxaspiro (5,5) undecane, triethylene glycol-bis-3- (3-tertbutyl-4-hydroxy-5 -Methylphenyl) propionate, n-octyl-3- (3,5-di-tertbutyl-4-hydroxyphenyl) propionate , Pentaerythryltetrakis [3- (3,5-di-tertbutyl-4-hydroxyphenyl) propionate] (trade name IRGANOX 1010, manufactured by Ciba Specialty Chemicals), tris (3,5-di-tertbutylhydroxybenzyl) Examples thereof include isocyanurate and thiodiethylenebis [3- (3,5-ditertbutyl-4-hydroxyphenyl) propionate], and among these, a phenol-based thermal polymerization inhibitor is more preferable.

  The content of the thermal polymerization inhibitor may be appropriately determined according to the polymer contained as the main component and the application and use environment of the adhesive composition, but is 0.1% by mass relative to the polymer contained as the main component. It is preferably 10.0% by mass or less, more preferably 0.5% by mass or more and 7.0% by mass or less, and most preferably 1.0% by mass or more and 5.0% by mass. It is as follows. By making it within the above range, the effect of suppressing polymerization due to heat is satisfactorily exhibited, and it is possible to further facilitate the peeling of the adhesive layer after the high temperature process. Moreover, generation | occurrence | production of a crack can be prevented by setting it as the said range.

  The adhesive composition according to the present embodiment includes a miscible additive, for example, an additional resin for improving the performance of the adhesive, a plasticizer, as long as the essential characteristics of the present invention are not impaired. Conventionally used ones such as an adhesion aid, a stabilizer, a colorant and a surfactant can be further added.

  Furthermore, the adhesive composition may be diluted with an organic solvent for viscosity adjustment as long as the essential characteristics of the present invention are not impaired. 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, 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, methoxypropionate Can be exemplified Le, esters such as ethyl ethoxypropionate. 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, monomethyl ether, monoethyl ether, monopropyl ether, monobutyl ether or monophenyl of dipropylene glycol or dipropylene glycol monoacetate Polyhydric alcohols such as ether and derivatives thereof are more preferable.

  The amount of the organic solvent used is appropriately set according to the film thickness to which the adhesive composition is applied, and may be any concentration that allows the adhesive composition to be applied on a support such as a semiconductor wafer. It is not limited. Generally, it is used so that the solid content concentration of the adhesive composition is in the range of 20 to 70 mass%, more preferably 25 to 60 mass%.

(Method for preparing adhesive composition)
(Copolymerization reaction)
The copolymerization reaction of the monomer composition may be performed by a known method and is not particularly limited. For example, the polymer which is the main component of the adhesive composition according to the present invention can be obtained by stirring the monomer composition using an existing stirring device.

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

  In the copolymerization reaction, a solvent may be appropriately used. As the solvent, the organic solvent described above can be used, and among them, propylene glycol monomethyl ether acetate (hereinafter referred to as “PGMEA”) is more preferable.

  Further, in the copolymerization reaction according to the present embodiment, a polymerization initiator may be used as appropriate. 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 acid peroxide, tert-butylperoxy-2-ethylhexanoate, tert-butylperoxypivalate, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, etc. An organic peroxide is mentioned. Of these, only one type may be used, or two or more types may be appropriately mixed and used. Further, the amount of the polymerization initiator used is not particularly limited as long as it is appropriately set according to the combination of the monomer compositions, reaction conditions, and the like.

  The preferred range of the weight average molecular weight of the polymer used in the present invention is preferably 10,000 to 300,000, more preferably 20,000 to 200,000, and particularly preferably 30,000 to 150,000. By setting the weight average molecular weight to 10,000 or more, good flexibility can be provided. Moreover, heat resistance becomes favorable by a weight average molecular weight being 300000 or less.

[2: Adhesive film]
The adhesive composition according to the present invention described above can employ various usage forms depending on the application. For example, a method of forming an adhesive layer by applying onto a workpiece such as a semiconductor wafer while in a liquid state may be used, or an adhesive film according to the present invention, that is, a film such as a flexible film in advance. After forming an adhesive layer containing any one of the above-mentioned adhesive compositions on the top, it is allowed to dry, and this film (adhesive film) is attached to a workpiece (adhesive film method). It may be used.

  Thus, the adhesive film which concerns on this invention is equipped with the adhesive bond layer containing one of said adhesive composition on a film.

  Therefore, when the monomer composition contains a maleimide group-containing monomer, the heat resistance of the adhesive composition constituting the adhesive layer is improved, and the adhesive film has excellent heat resistance and adhesive strength in a high temperature environment. Can be obtained.

  Moreover, when the adhesive composition contains a thermal polymerization inhibitor, it is possible to obtain an adhesive film that improves the solubility of the adhesive layer and facilitates peeling.

  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 overlaid on the workpiece, and then the above-mentioned film is peeled off from the adhesive layer to remove the adhesive on the workpiece. Layers can be easily provided.

  Therefore, when this adhesive film is used, an adhesive having better film thickness uniformity and surface smoothness than the case where an adhesive composition is applied directly on a workpiece to form an adhesive layer. A layer can be formed.

  As the film used for the production of an adhesive film, an adhesive layer formed on the film can be peeled off from the film, and the adhesive layer can be transferred onto a surface to be treated such as a protective substrate or a wafer. It is not limited as long as it is a mold 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, and a polyvinyl chloride, is mentioned. It is preferable that a release treatment is performed on the film as necessary to facilitate transfer.

  As a method of forming the adhesive layer on the film, a known method is used according to the desired thickness and uniformity of the adhesive layer, and the dry thickness of the adhesive layer on the film is 10 to 10. The method of apply | coating the adhesive composition which concerns on this invention so that it may be set to 1000 micrometers is mentioned.

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

  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 roller such as a winding roller.

  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 protective substrate for precision processing of a semiconductor wafer 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 attaching a substrate to a support plate, particularly when grinding and thinning a substrate such as a semiconductor wafer (for example, JP, 2005-191550, A).

[Stripping solution]
As a remover for removing the adhesive composition according to the present invention, a commonly used remover can be used. In particular, propylene glycol monomethyl ether acetate (hereinafter referred to as “PGMEA”), ethyl acetate, A stripping solution containing methyl ethyl ketone as the main component is preferable in terms of environmental load and stripping property.

  Examples of the present invention will be described below, but the present invention is not limited to these examples.

  First, a specific method for preparing the adhesive composition according to Example 1 will be described.

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 p-hydroxystyrene as a monomer monomer as shown in Table 1 20 g, 19 g of 1-adamantyl methacrylate, and 61 g of styrene having no substituent introduced thereto 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 composed of 13.33 g of PGMEA and 1 g of t-butylperoxy 2-ethylhexanoate (polymerization initiator) is added from a dropping nozzle. 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 liquid mixture consisting of 25.10 g of PGMEA and 0.3 g of t-butylperoxy 2-ethylhexanoate was added dropwise 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, the polymerization reaction solution was aged at 100 ° C. for 3 hours as it was, and then the polymerization reaction solution was heated up until reflux of the solvent was observed, and aged for 1 hour to complete the polymerization and synthesize a polymer.

The synthesized polymer was dissolved in PGMEA to prepare an adhesive composition having a polymer concentration of 40% by mass. After the prepared adhesive composition was applied on a 6-inch silicon wafer, it was dried at 110 ° C., 150 ° C., and 200 ° C. for 3 minutes for a total of 9 minutes, respectively. Formed. The glass coating point (Tg) and softening point (SP) of the adhesive composition were measured using TMA (thermomechanical analyzer) for the formed coating film. The reason why TMA was used instead of DSC (Differential Scanning Calorimetry) for the glass transition point is to verify that the glass transition point is close to the sink during actual use. As measurement conditions, the weight was 0.2 kg / cm ² , and the temperature elevation recipe was normal temperature to 300 ° C. (10 ° C./min). Under these conditions, the point at which the subduction starts was defined as the glass transition point, and the point at which the greater subduction began was defined as the softening point. In addition, in FIG. 1, the graph which shows the measurement result by TMA in Example 3, the comparative example 1, and the comparative example 2 mentioned later is shown.

  As shown in Table 1, the adhesive composition according to Comparative Example 1 was obtained by the same procedure as in Example 1 except that methyl methacrylate was charged instead of 1-adamantyl methacrylate as shown in Table 1. It was. In the same manner as in Example 1, the glass transition point and the softening point were measured.

  The adhesive composition according to Example 2 was the same procedure as Example 1 except that 60 g of p-hydroxystyrene and 40 g of 1-adamantyl methacrylate were charged as monomer monomers as shown in Table 1. Obtained. In the same manner as in Example 1, the glass transition point and the softening point were measured.

  As shown in Table 1, the adhesive composition according to Example 3 was prepared by using p- (tert-butyl) styrene instead of styrene having no substituent as shown in Table 1. Obtained by a procedure similar to that of Example 1. In the same manner as in Example 1, the glass transition point and the softening point were measured.

  As shown in Table 1, the adhesive composition according to Comparative Example 2 was obtained by the same procedure as Example 3 except that methyl methacrylate was charged instead of 1-adamantyl methacrylate as shown in Table 1. It was. In the same manner as in Example 1, the glass transition point and the softening point were measured.

  Table 1 shows the measurement results of the composition of the monomer composition and the weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn) of the monomer composition and the glass transition point and the softening point of the adhesive composition in Examples and Comparative Examples. Summarized.

  As can be seen from a comparison between Examples and Comparative Examples (especially, Example 1 and Comparative Example 1, Example 3 and Comparative Example 2), methyl methacrylate in the composition of the monomer composition was replaced with 1-adamantyl. By replacing with methacrylate, the glass transition point and softening point were greatly increased.

  Similarly, FIG. 1 also shows that the glass transition point and the softening point increased in the examples as compared with the comparative example.

  The adhesive composition and adhesive film according to the present invention can be suitably used in a semiconductor wafer or chip processing step.

Claims (5)

  An adhesive composition comprising a polymer obtained by polymerizing a monomer composition containing (meth) acrylic acid having an adamantyl group introduced therein and hydroxystyrene as a main component.   The (meth) acrylic acid introduced with the adamantyl group is 1-adamantyl (meth) acrylate, 2-adamantyl (meth) acrylate, 2-methyl-2-adamantyl (meth) acrylate, 2-ethyl-2-adamantyl ( The adhesive composition according to claim 1, wherein the adhesive composition is a compound selected from the group consisting of (meth) acrylate and 3-hydroxy-1-adamantyl (meth) acrylate.   The adhesive composition according to claim 1 or 2, wherein the monomer composition further contains at least one of styrene and (meth) acrylic acid.   The content of (meth) acrylic acid into which the adamantyl group is introduced in the monomer composition is in the range of 5% by mass or more and 80% by mass or less. The adhesive composition according to claim 1.   An adhesive film comprising an adhesive layer containing the adhesive composition according to any one of claims 1 to 4 on the film.

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