JP6085161B2 - Adhesive composition and adhesive film - Google Patents

Description

  The present invention relates to an adhesive composition and an adhesive film.

  Hydrocarbon adhesives are known as adhesives for bonding a wafer and a support plate serving as a support for the wafer (Patent Documents 1 and 2).

Special table 2009-529065 (released on August 13, 2009) Special table 2010-506406 (released February 25, 2010)

  As mobile phones, digital AV devices, IC cards, etc. become more sophisticated, there is an increasing demand for highly integrated silicon in the package by reducing the size and thickness of the mounted semiconductor silicon chip (hereinafter referred to as the chip). ing. For example, in an integrated circuit that integrates a plurality of chips into one package such as CSP (chip size package) or MCP (multi-chip package), a reduction in thickness is required. In order to achieve high integration of chips in the package, it is necessary to reduce the thickness of the chip to a range of 25 to 150 μm.

  However, since a semiconductor wafer (hereinafter referred to as a wafer) serving as a chip base becomes thin by grinding, its strength is weakened, and the wafer is likely to be cracked or warped. Further, since it is difficult to automatically transport a wafer whose strength has been reduced by making it thin, it has to be transported manually, and the handling thereof is complicated.

  Therefore, a wafer handling system has been developed that maintains the strength of the wafer and prevents the occurrence of cracks and warpage of the wafer by bonding a plate made of glass, hard plastic or the like called a support plate to the wafer to be ground. . Since the wafer strength can be maintained by the wafer handling system, the transport of the thinned semiconductor wafer can be automated.

  In the wafer handling system, the wafer and the support plate are bonded together using an adhesive tape, a thermoplastic resin, an adhesive, or the like. Then, after thinning the wafer to which the support plate is attached, the support plate is peeled from the substrate before dicing the wafer. When an adhesive is used for bonding the wafer and the support plate, the adhesive is dissolved to peel the wafer from the support plate.

  Among hydrocarbon-based adhesives according to the prior art, in particular, an adhesive mainly composed of a high molecular weight polymer having low heat fluidity requires a very high temperature or high pressure for bonding the wafer and the support plate. The For example, since a device having a solder bump whose reflow temperature is not high cannot be exposed to a high temperature of 220 ° C. or higher, even when using the above-described conventional hydrocarbon-based adhesive, the bonding temperature cannot be raised, It is difficult to suitably bond the wafer and the support plate.

  The present invention has been made in view of the above problems, and an object thereof is to provide an adhesive composition capable of bonding, for example, a wafer and a support plate without applying high temperature or high pressure. is there.

  In order to solve the above problems, an adhesive composition according to the present invention includes an elastomer containing a styrene unit as a constituent unit of a main chain, and an acrylic resin having a 5% thermal weight loss temperature of 280 ° C. or higher. It is characterized by being.

  The adhesive composition according to the present invention has an effect that, for example, a wafer and a support plate can be suitably bonded without applying high temperature or high pressure.

  The adhesive composition according to the present invention includes an elastomer containing a styrene unit as a constituent unit of the main chain and an acrylic resin having a 5% thermal weight loss temperature of 280 ° C. or higher.

[Elastomer]
The elastomer contained in the adhesive composition according to the present invention contains a styrene unit as a constituent unit of the main chain. The elastomer contained in the adhesive composition according to the present invention preferably has a content of the styrene unit in the range of 14% by weight or more and 50% by weight or less. Furthermore, it is preferable that the elastomer contained in the adhesive composition according to the present invention has a weight average molecular weight in the range of 10,000 to 200,000.

  In the present specification, the “structural unit” refers to a structure resulting from a single monomer in a structure constituting a polymer.

  In the present specification, the “styrene unit” is a constituent unit derived from the styrene contained in the polymer when the styrene is polymerized, and the “styrene unit” may have a substituent. Examples of the substituent include an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, an alkoxyalkyl group having 1 to 5 carbon atoms, an acetoxy group, and a carboxyl group.

  If the content of the styrene unit is in the range of 14% by weight or more and 50% by weight or less and the weight average molecular weight of the elastomer is in the range of 10,000 or more and 200,000 or less, it is easy for a hydrocarbon solvent described later. Therefore, the adhesive layer can be removed more easily and quickly. Further, since the content of the styrene unit and the weight average molecular weight are in the above ranges, a resist solvent (eg, PGMEA, PGME, etc.), acid (hydrofluoric acid) exposed when the wafer is subjected to a resist lithography process. Etc.) and excellent resistance to alkali (TMAH etc.).

  The content of styrene units is more preferably 17% by weight or more, and more preferably 40% by weight or less.

  A more preferable range of the weight average molecular weight is 20,000 or more, and a more preferable range is 150,000 or less.

  As the elastomer, various elastomers are used as long as the content of styrene units is in the range of 14% by weight to 50% by weight and the weight average molecular weight of the elastomer is in the range of 10,000 to 200,000. be able to. For example, polystyrene-poly (ethylene / propylene) block copolymer (SEP), styrene-isoprene-styrene block copolymer (SIS), styrene-butadiene-styrene block copolymer (SBS), styrene-butadiene-butylene-styrene block copolymer (SBBS). , Ethylene-propylene terpolymer (EPT) and hydrogenated products thereof, styrene-ethylene-butylene-styrene block copolymer (SEBS), styrene-ethylene-propylene-styrene block copolymer (styrene-isoprene-styrene block copolymer) ( SEPS), styrene-ethylene-ethylene-propylene-styrene block copolymer (SEEPS), styrene-ethylene- in which the styrene block is reactively crosslinked Tylene-propylene-styrene block copolymer (Septon V9461 (manufactured by Kuraray Co., Ltd.)), a styrene block having a reactive crosslinking type styrene-ethylene-butylene-styrene block copolymer (Septon V9827 (manufactured by Kuraray Co., Ltd.) )) And the like, and the content of the styrene unit and the weight average molecular weight are in the above-mentioned range.

  Of the elastomers, hydrogenated products are more preferable. If it is a hydrogenated product, the stability to heat is improved, and degradation such as decomposition and polymerization hardly occurs. Moreover, it is more preferable from the viewpoint of solubility in hydrocarbon solvents and resistance to resist solvents.

  Further, among elastomers, those having both ends of a styrene block polymer are more preferable. This is because styrene having high thermal stability is blocked at both ends, thereby exhibiting higher heat resistance.

  More specifically, the elastomer is more preferably a hydrogenated product of a block copolymer of styrene and conjugated diene. Stability against heat is improved, and degradation such as decomposition and polymerization hardly occurs. Moreover, higher heat resistance is exhibited by blocking styrene having high thermal stability at both ends. Furthermore, it is more preferable from the viewpoint of solubility in hydrocarbon solvents and resistance to resist solvents.

  Examples of commercially available products that can be used as an elastomer contained in the adhesive composition according to the present invention include “Septon (trade name)” manufactured by Kuraray Co., Ltd., “Hibler (trade name)” manufactured by Kuraray Co., Ltd. and “Tuftec” manufactured by Asahi Kasei Co., Ltd. (Trade name) ”,“ Dynalon (trade name) ”manufactured by JSR Corporation, and the like.

  The content of the elastomer contained in the adhesive composition according to the present invention is, for example, preferably 50 parts by weight or more and 99 parts by weight or less, based on 100 parts by weight of the total amount of the adhesive composition, and 60 parts by weight or more and 99 parts by weight. Part or less is more preferable, and 70 parts by weight or more and 95 parts by weight or less is most preferable. By setting it as these ranges, a wafer and a support body can be bonded together suitably, maintaining heat resistance.

  A plurality of types of elastomers may be mixed. That is, the adhesive composition according to the present invention may include a plurality of types of elastomers. It is sufficient that at least one of the plurality of types of elastomers includes a styrene unit as a constituent unit of the main chain. Further, at least one of the plurality of types of elastomers has a styrene unit content in the range of 14 wt% or more and 50 wt% or less, or a weight average molecular weight in the range of 10,000 or more and 200,000 or less. If so, it is within the scope of the present invention. Moreover, in the adhesive composition which concerns on this invention, when several types of elastomer is included, as a result of mixing, you may adjust so that content of a styrene unit may become said range. For example, Septon 4033 of Kuraray Septon (trade name) having a styrene unit content of 30% by weight and Septon 2063 of Septon (trade name) having a styrene unit content of 13% by weight is a pair of weight ratios. When mixed at 1, the styrene content with respect to the whole elastomer contained in the adhesive composition is 21 to 22% by weight, and therefore 14% by weight or more. For example, when a styrene unit of 10% by weight and 60% by weight are mixed on a one-to-one basis, the result is 35% by weight, which is within the above range. The present invention may be in such a form. Moreover, it is most preferable that the plurality of types of elastomers contained in the adhesive composition according to the present invention all contain styrene units in the above range and have a weight average molecular weight in the above range.

[Acrylic resin]
The acrylic resin contained in the adhesive composition according to the present invention may have a 5% thermal weight loss temperature of 280 ° C. or higher.

  Since the adhesive composition contains an acrylic resin, which is a low molecular plastic component, it has high thermal fluidity and, for example, bonds a wafer and a support plate (support) without applying high temperature or high pressure. Is possible. Therefore, the adhesive composition can suitably bond the wafer and the support even at a bonding temperature of 220 ° C. or lower, for example.

  Further, when the 5% thermal weight reduction temperature of the acrylic resin is 280 ° C. or higher, the heat resistance necessary in the wafer processing process can be obtained. It can be said that the acrylic resin only needs to have a heat resistance of 220 ° C. or higher, which is required in a wafer processing process, for example. The 5% thermal weight loss temperature of the acrylic resin is more preferably 300 ° C. or higher.

  Here, the 5% thermal weight loss temperature of the acrylic resin is such that when the heating is started at 25 ° C. in a nitrogen atmosphere and the heating temperature is increased by 10 ° C. at 1 minute intervals, the acrylic resin is The temperature when the weight is reduced by 5% by weight of the initial weight. In addition, the weight of acrylic resin can be measured with a thermogravimetry apparatus.

  Examples of the acrylic resin include a resin polymerized using (meth) acrylic acid ester as a monomer.

  Examples of (meth) acrylic acid esters include (meth) acrylic acid alkyl esters having a chain structure, (meth) acrylic acid esters having an aliphatic ring, and (meth) acrylic acid esters having an aromatic ring. It is preferable to use (meth) acrylic acid ester having an aliphatic ring.

  Examples of the (meth) acrylic acid alkyl ester having a chain structure include 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. . As acrylic long-chain alkyl esters, acrylic or methacrylic acid whose alkyl group is n-pentadecyl group, n-hexadecyl group, n-heptadecyl group, n-octadecyl group, n-nonadecyl group, n-eicosyl group, etc. Examples include alkyl esters. The alkyl group may be branched.

  Examples of the acrylic alkyl ester having an alkyl group having 1 to 14 carbon atoms include known acrylic alkyl esters used in existing acrylic adhesives. For example, an alkyl group of 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, lauryl group, tridecyl group, etc. Examples include esters.

  Examples of (meth) acrylic acid ester having an aliphatic ring include cyclohexyl (meth) acrylate, cyclopentyl (meth) acrylate, 1-adamantyl (meth) acrylate, norbornyl (meth) acrylate, isobornyl (meth) acrylate, and tricyclodecanyl. (Meth) acrylate, tetracyclododecanyl (meth) acrylate, dicyclopentanyl (meth) acrylate and the like can be mentioned, and isobornyl methacrylate and dicyclopentanyl (meth) acrylate are more preferable.

  The (meth) acrylic acid ester having an aromatic ring is not particularly limited. Examples of the aromatic ring include a phenyl group, a benzyl group, a tolyl group, a xylyl group, a biphenyl group, a naphthyl group, and an anthracenyl group. A phenoxymethyl group, a phenoxyethyl group, and the like. The aromatic ring may have a chain or branched alkyl group having 1 to 5 carbon atoms. Specifically, phenoxyethyl acrylate is preferable.

  The acrylic resin contained in the adhesive composition according to the present invention may be polymerized using one kind of monomers among the above-mentioned (meth) acrylic acid ester monomers. The polymer may be polymerized using any of these types of monomers.

  The acrylic resin contained in the adhesive composition according to the present invention is a resin polymerized by using the above-mentioned (meth) acrylic acid ester monomer and another monomer polymerizable with this monomer. Also good. Examples of the monomer that can be polymerized with a monomer such as (meth) acrylic acid ester include styrene or a derivative of styrene, and a monomer containing a maleimide group.

  As monomers containing a maleimide group, N-methylmaleimide, N-ethylmaleimide, Nn-propylmaleimide, N-isopropylmaleimide, Nn-butylmaleimide, N-isobutylmaleimide, N-sec-butylmaleimide, N -An alkyl group such as tert-butylmaleimide, Nn-pentylmaleimide, Nn-hexylmaleimide, Nn-heptylmaleimide, Nn-octylmaleimide, N-laurylmaleimide, N-stearylmaleimide Maleimides having aliphatic hydrocarbon groups such as maleimide, N-cyclopropylmaleimide, N-cyclobutylmaleimide, N-cyclopentylmaleimide, N-cyclohexylmaleimide, N-cycloheptylmaleimide, N-cyclooctylmaleimide, N Phenylmaleimide, N-m-methylphenyl maleimide, N-o-methylphenyl maleimide, aromatic maleimide having an aryl group such as a N-p-methylphenyl maleimide.

  The acrylic resin preferably contains a styrene unit as a constituent unit. When the acrylic resin contains a styrene unit, the heat resistance of the acrylic resin is improved, and it is also preferable from the viewpoints of solubility in a solvent and resistance to a resist solvent.

  The acrylic resin is preferably soluble in a hydrocarbon solvent. Examples of the hydrocarbon solvent in which the acrylic resin can be dissolved include decahydronaphthalene. Details of other hydrocarbon solvents will be described later.

  The solubility parameter (SP value) of the acrylic resin is preferably 6 or more and 10 or less. When the SP value is 6 or more and 10 or less, the acrylic resin and the elastomer are compatible with each other, and a more stable adhesive composition is obtained. The SP value of the acrylic resin is more preferably 6.5 or more and 9.5 or less.

  The weight average molecular weight of the acrylic resin is preferably 2,000 or more and 70,000 or less. When the acrylic resin has a weight average molecular weight of 2,000 or more and 70,000 or less, for example, an adhesive composition having thermal fluidity suitable for bonding a wafer and a support can be provided. The weight average molecular weight of the acrylic resin is more preferably 5,000 or more and 50,000 or less.

  The content of the acrylic resin is, for example, preferably 1% by weight or more and 50% by weight or less, and preferably 1% by weight or more and 40% by weight or less, based on 100 parts by weight of the total amount of the adhesive composition. Is more preferable, and most preferably 5% by weight or more and 30% by weight or less. By setting it as these ranges, a wafer and a support body can be bonded together suitably, maintaining heat resistance.

  A plurality of types of acrylic resins may be mixed. That is, the adhesive composition according to the present invention may include a plurality of types of acrylic resins. If the 5% thermal weight loss temperature in at least one of the plurality of types of acrylic resins is 280 ° C. or higher, it is within the scope of the present invention. The plurality of types of acrylic resins contained in the adhesive composition according to the present invention most preferably have a 5% thermal weight loss temperature of 280 ° C. or higher.

(solvent)
The solvent contained in the adhesive composition according to the present invention may be any solvent as long as it has a function of dissolving the elastomer and the acrylic resin, such as a nonpolar hydrocarbon solvent, a polar and nonpolar petroleum solvent, and the like. Can be used.

  Preferably, the solvent can comprise a condensed polycyclic hydrocarbon. When the solvent contains a condensed polycyclic hydrocarbon, it is possible to avoid white turbidity that may occur when the adhesive composition is stored in a liquid form (especially at a low temperature), thereby improving product stability. .

  Examples of the hydrocarbon solvent include linear, branched or cyclic hydrocarbons. For example, straight chain hydrocarbons such as hexane, heptane, octane, nonane, methyloctane, decane, undecane, dodecane, tridecane, etc., branched hydrocarbons having 3 to 15 carbon atoms; p-menthane, o-menthane, m -Saturated aliphatic hydrocarbons such as menthane, diphenylmenthane, 1,4-terpine, 1,8-terpine, bornane, norbornane, pinane, tujang, kalan, longifolene, α-terpinene, β-terpinene, γ-terpinene, α -Pinene, β-pinene, α-tujon, β-tujon and the like.

  Examples of the petroleum solvent include cyclohexane, cycloheptane, cyclooctane, naphthalene, decahydronaphthalene, tetrahydronaphthalene and the like.

  The condensed polycyclic hydrocarbon is a condensed ring hydrocarbon formed by two or more monocycles supplying only one side of each ring to each other, and is a carbon obtained by condensing two monocycles. It is preferable to use hydrogen.

  Such hydrocarbons include combinations of 5-membered and 6-membered rings, or combinations of two 6-membered rings. Examples of hydrocarbons combining 5-membered and 6-membered rings include indene, pentalene, indane, tetrahydroindene and the like. Examples of hydrocarbons combining two 6-membered rings include naphthalene, tetrahydronaphthalene ( Tetralin) and decahydronaphthalene (decalin).

  Further, when the solvent contains the condensed polycyclic hydrocarbon, the component contained in the solvent may be only the condensed polycyclic hydrocarbon, or contains other components such as saturated aliphatic hydrocarbon, for example. You may do it. In this case, the content of the condensed polycyclic hydrocarbon is preferably 40 parts by weight or more, more preferably 60 parts by weight or more based on the entire hydrocarbon solvent. When the content of the condensed polycyclic hydrocarbon is 40 parts by weight or more of the entire hydrocarbon solvent, high solubility in the resin can be exhibited. If the mixing ratio of the condensed polycyclic hydrocarbon and the saturated aliphatic hydrocarbon is within the above range, the odor of the condensed polycyclic hydrocarbon can be alleviated.

  In addition, the content of the solvent in the adhesive composition of the present invention may be appropriately adjusted according to the thickness of the adhesive layer formed using the adhesive composition. When the total amount is 100 parts by weight, it is preferably in the range of 20 to 90 parts by weight. If the content of the solvent is within the above range, the viscosity can be easily adjusted.

(Thermal polymerization inhibitor)
In the present invention, the adhesive composition may contain a thermal polymerization inhibitor. The thermal polymerization inhibitor has a function of preventing radical polymerization reaction due to heat. Specifically, since the thermal polymerization inhibitor is highly reactive to radicals, it reacts preferentially over the monomer and inhibits polymerization of the monomer. In the adhesive composition containing such a thermal polymerization inhibitor, the polymerization reaction is suppressed under a high temperature environment (particularly, 250 ° C. to 350 ° C.).

  For example, in a semiconductor manufacturing process, there is a high temperature process in which a wafer to which a support plate (support) is bonded is heated at 250 ° C. for 1 hour. At this time, when the polymerization of the adhesive composition occurs at a high temperature, the solubility in a peeling solution for peeling the support plate from the wafer after the high-temperature process is lowered, and the support plate cannot be peeled well from the wafer. However, in the adhesive composition of the present invention containing a thermal polymerization inhibitor, since the oxidation due to heat and the polymerization reaction accompanying it are suppressed, the support plate can be easily peeled off even after a high temperature process, Generation of residue can be suppressed.

  Although it will not specifically limit if it is effective in preventing the radical polymerization reaction by heat | fever as a thermal-polymerization inhibitor, The thermal-polymerization inhibitor which has a phenol is preferable. Thereby, good solubility can be ensured even after high temperature treatment in the atmosphere. As such a thermal polymerization inhibitor, it is possible to use a hindered phenol antioxidant, for example, 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 "-ethylidene tris (2- Methylphenol), 4,4 ', 4 "-ethylident Sphenol, 1,1,3-tris (2,5-dimethyl-4-hydroxyphenyl) -3-phenylpropane, 2,6-di-tert-butyl-4-methylphenol, 2,2′-methylenebis ( 4-methyl-6-tert-butylphenol), 4,4′-butylidenebis (3-methyl-6-tert-butylphenol), 4,4′-thiobis (3-methyl-6-tert-butylphenol), 3,9 -Bis [2- (3- (3-tert-butyl-4-hydroxy-5-methylphenyl) -propionyloxy) -1,1-dimethylethyl] -2,4,8,10-tetraoxaspiro (5 , 5) Undecane, triethylene glycol-bis-3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionate, n Octyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, pentaerythryltetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate] (trade name) IRGANOX 1010 (manufactured by Ciba Japan), tris (3,5-di-tert-butylhydroxybenzyl) isocyanurate, thiodiethylenebis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate] Is mentioned. Only one type of thermal polymerization inhibitor may be used, or two or more types may be used in combination.

  The content of the thermal polymerization inhibitor may be appropriately determined according to the type of elastomer, the type of acrylic resin, and the use and use environment of the adhesive composition. For example, the elastomer and the acrylic resin are combined. When the amount of the resin is 100 parts by weight, it is preferably 0.1 parts by weight or more and 10 parts by weight or less. If the content of the thermal polymerization inhibitor is within the above range, the effect of suppressing the polymerization due to heat is satisfactorily exerted, and the decrease in the solubility of the adhesive composition in the stripping solution can be further suppressed after the high temperature process. .

(Additive solvent)
Moreover, the structure which contains the addition solvent which consists of a composition different from the solvent for melt | dissolving a thermal-polymerization inhibitor and melt | dissolving an elastomer and acrylic resin may be sufficient as the adhesive composition which concerns on this invention. Although it does not specifically limit as an additive solvent, The organic solvent which melt | dissolves the component contained in an adhesive composition can be used.

  As an organic solvent, what is necessary is just to melt | dissolve each component of an adhesive composition, for example, and it can be set as a uniform solution, and it can use it combining arbitrary 1 type (s) or 2 or more types.

  Specific examples of the organic solvent include, for example, terpene solvents having an oxygen atom, a carbonyl group or an acetoxy group as a polar group, for example, geraniol, nerol, linalool, citral, citronellol, menthol, isomenthol, neomenthol, α-terpineol, β-terpineol, γ-terpineol, terpinen-1-ol, terpinen-4-ol, dihydroterpinyl acetate, 1,4-cineole, 1,8-cineole, borneol, carvone, yonon, thuyon, For example, camphor. Lactones such as γ-butyrolactone; Ketones such as acetone, methyl ethyl ketone, cyclohexanone (CH), methyl-n-pentyl ketone, methyl isopentyl ketone, 2-heptanone; ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol Polyhydric alcohols such as ethylene glycol monoacetate, diethylene glycol monoacetate, propylene glycol monoacetate, dipropylene glycol monoacetate, etc., compounds having an ester bond, monohydric ethers of the above polyhydric alcohols or compounds having an ester bond A monoalkyl ether such as monoethyl ether, monopropyl ether, monobutyl ether or an ether bond such as monophenyl ether Derivatives of polyhydric alcohols such as propylene glycol monomethyl ether acetate (PGMEA) and propylene glycol monomethyl ether (PGME) are preferred among them; cyclic ethers such as dioxane, methyl lactate, lactic acid Esters such as ethyl (EL), methyl acetate, ethyl acetate, butyl acetate, methyl pyruvate, ethyl pyruvate, methyl methoxypropionate, ethyl ethoxypropionate; anisole, ethyl benzyl ether, cresyl methyl ether, diphenyl ether, di Aromatic organic solvents such as benzyl ether, phenetole, and butyl phenyl ether can be exemplified.

  The content of the additive solvent may be appropriately determined according to the type of the thermal polymerization inhibitor, for example, a solvent (main solvent) that dissolves the elastomer and acrylic resin and a solvent (addition that dissolves the thermal polymerization inhibitor). When the total amount of the solvent is 100 parts by weight, it is preferably 1 part by weight or more and 50 parts by weight or less, and more preferably 1 part by weight or more and 30 parts by weight or less. When the content of the additive solvent is within the above range, the thermal polymerization inhibitor can be sufficiently dissolved.

(Other ingredients)
The adhesive composition may further contain other miscible materials as long as the essential characteristics of the present invention are not impaired. For example, various commonly used additives such as an additional resin for improving the performance of the adhesive, a plasticizer, an adhesion aid, a stabilizer, a colorant, and a surfactant can be further used.

(Method for preparing adhesive composition)
The method for preparing the adhesive composition according to the present invention is not particularly limited, and a known method may be used. For example, an elastomer and an acrylic resin are dissolved in a solvent, and each composition is adjusted using an existing stirring device. By stirring, the adhesive composition according to the present invention can be obtained.

  In addition, when adding a thermal polymerization inhibitor to the adhesive composition according to the present invention, it is possible to add a thermal polymerization inhibitor that has been previously dissolved in an additive solvent for dissolving the thermal polymerization inhibitor. preferable.

[Use of adhesive composition according to the present invention]
The adhesive composition according to the present invention is used for bonding a substrate and a support of the substrate. Preferably, it is used for bonding the wafer and the support of the wafer.

  The support is, for example, a member that plays a role of supporting the wafer in a thinning process, and is bonded to the wafer by the adhesive composition according to the present invention. In one Embodiment, the support body is formed with the glass or silicon whose film thickness is 500-1000 micrometers, for example.

  In one embodiment, the support is provided with a hole penetrating the support in the thickness direction. The support and the substrate can be easily separated by pouring a solvent for dissolving the adhesive composition between the support and the wafer through the holes.

  In another embodiment, a reaction layer may be interposed between the support and the wafer in addition to the adhesive layer. The reaction layer is altered by absorbing light irradiated through the support, and the support and wafer can be easily altered by irradiating the reaction layer with light or the like to alter the reaction layer. Can be separated. In this case, it is preferable to use a support body in which a hole penetrating in the thickness direction is not provided.

The light applied to the reaction layer is, for example, a solid laser such as a YAG laser, Libby laser, glass laser, YVO ₄ laser, LD laser, or fiber laser, or a liquid laser such as a dye laser, depending on the wavelength that can be absorbed by the reaction layer. A gas laser such as a CO ₂ laser, an excimer laser, an Ar laser, or a He—Ne laser, a laser beam such as a semiconductor laser or a free electron laser, or a non-laser beam may be used as appropriate. The wavelength of light to be absorbed by the reaction layer is not limited to this, but may be, for example, light having a wavelength of 600 nm or less.

  The reaction layer may contain a light absorber that is decomposed by light or the like, for example. Examples of the light absorber include graphite powder, fine metal powder such as iron, aluminum, copper, nickel, cobalt, manganese, chromium, zinc, tellurium, metal oxide powder such as black titanium oxide, carbon black, or aromatic. Dye or pigment such as diamino metal complex, aliphatic diamine metal complex, aromatic dithiol metal complex, mercaptophenol metal complex, squarylium compound, cyanine dye, methine dye, naphthoquinone dye, anthraquinone dye Can be used. Such a reaction layer can be formed, for example, by mixing with a binder resin and coating on a support. A resin having a light absorbing group can also be used.

  Further, as the reaction layer, an inorganic film or an organic film formed by a plasma CVD method may be used. For example, a metal film can be used as the inorganic film. As the organic film, a fluorocarbon film can be used. Such a reaction film can be formed on a support by a plasma CVD method, for example.

  In addition, the adhesive composition according to the present invention is suitably used for bonding a wafer to be subjected to a thinning process after being bonded to a support and the support. As described above, the support retains the strength of the wafer when the wafer is thinned. The adhesive composition according to the present invention is suitably used for bonding such a wafer and a support.

  Further, the adhesive composition according to the present invention does not need to be subjected to high temperature or high pressure for bonding between the wafer and the support, and can be applied to, for example, a wafer having a solder bump whose reflow temperature is not high. . Specifically, the wafer and the support can be suitably bonded at a bonding temperature of 220 ° C. or less.

  Moreover, since the adhesive composition according to the present invention has excellent heat resistance, it is suitable for bonding a wafer that is exposed to an environment of 150 ° C. or higher after being bonded to the support and the support. Used. Specifically, it can be suitably used in an environment of 180 ° C. or higher, and further 220 ° C. or higher.

  In addition, the manufacturing method of the laminated body which adhere | attaches a wafer and a support body at 220 degrees C or less using the adhesive composition which concerns on this invention, the thinning method of the wafer which thins the wafer of the said laminated body, and the said laminated body A method of heating at a temperature of 220 ° C. or higher is also within the scope of the present invention.

[Removal of the adhesive layer formed by the adhesive composition]
When the adhesive layer is removed after separating the wafer and the substrate bonded by the adhesive composition according to the present invention by altering the reaction layer, etc., the above solvent is used to dissolve easily. Can be removed. In addition, by directly supplying a solvent to the adhesive layer in a state where the wafer and the support are bonded without using the reaction layer, the adhesive layer is easily dissolved and the adhesive layer is removed. The wafer and the support can be separated. In this case, in order to increase the efficiency of supplying the solvent to the adhesive layer, it is more preferable that the support is provided with a through-hole.

[Adhesive film]
The adhesive composition according to the present invention can employ various usage forms depending on the application. For example, a method of forming an adhesive layer by coating on a workpiece such as a semiconductor wafer 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 dried, and a method (adhesive film method) in which this film (adhesive film) is applied to a workpiece is used. May be.

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

  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 the adhesive film, the 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. There is no particular limitation 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.

[Adjustment of adhesive composition]
The elastomer (resin), acrylic resin (added resin), polymerization inhibitor, main solvent, and additive solvent used in Examples 1 to 15 and Comparative Examples 1 to 7 are shown in Table 1 below. In Table 1, “parts” are all parts by weight.

  As an elastomer, Septon 4033 (SEPS: polystyrene-poly (ethylene / propylene) block-polystyrene), Septon 8007 (SEBS: polystyrene-poly (ethylene / butylene) block-polystyrene), HG252 (made by Kuraray Co., Ltd.) SEEPS-OH: polystyrene-poly (ethylene-ethylene / propylene) block-polystyrene terminal hydroxyl group-modified), Toughtec (trade name) H1051 (SEBS, hydrogenated styrene-based thermoplastic elastomer), H1053 (SEBS, water) manufactured by Asahi Kasei Corporation Styrenic thermoplastic elastomer) was used. The “hydrogenation” in this example is a polymer obtained by hydrogenating the double bond of a block copolymer of styrene and butadiene.

  Table 2 below shows the styrene content in the elastomer used and the weight average molecular weight of the elastomer.

  Moreover, as acrylic resin, A1-A12 shown in Table 3 was used. These acrylic resins are resins obtained by synthesizing respective monomers by known radical polymerization. The compositions, molecular weights, and 5 wt% thermogravimetric reduction temperatures of these acrylic resins are shown in Table 3 below. The weight average molecular weight was measured by GPC (gel permeation chromatograph). The composition is a numerical value described in the description attached to each product. 5 wt% thermogravimetric decrease temperature, using a thermogravimetric measuring device (manufactured by Seiko Instruments Inc., product name “TG-DTA6200”), 5 mg of acrylic resin was started to be heated at 25 ° C. in a nitrogen atmosphere, This is the temperature at which the weight is reduced by 5% by weight of the initial weight when the heating temperature is increased by 10 ° C. at 1 minute intervals.

  As shown in Table 3, in Examples 1 to 15, an acrylic resin having a 5 wt% thermogravimetric decrease temperature of 295 ° C, 300 ° C, or 310 ° C was used, and in Comparative Examples 5 to 7, 5 wt% thermogravimetric decrease temperature was used. Acrylic resin having a temperature of 260 ° C. or 265 ° C. was used. In Comparative Examples 1 to 4, no acrylic resin was used.

  As the thermal polymerization inhibitor, “IRGANOX (trade name) 1010” manufactured by BASF was used. As the main solvent, decahydronaphthalene represented by the following chemical formula (I) was used. Moreover, butyl acetate was used as an additive solvent.

  The adhesive composition of Example 1 was adjusted as follows. First, the elastomer shown in Table 1 was dissolved in decahydronaphthalene at a content weight ratio shown in Table 1 at a concentration of 25% and mixed with an acrylic resin having a content weight ratio shown in Table 1. Next, 1 part by weight of IRGANOX 1010 dissolved in butyl acetate was added. In this way, an adhesive composition was obtained. Moreover, about Examples 2-15 and Comparative Examples 5-7, the adhesive composition was obtained with the same method. In Comparative Examples 1 to 4, adhesive compositions were obtained in the same manner as in Example 1 except that no acrylic resin was used.

  The solution stability of the produced adhesive composition was confirmed visually. When the elastomer and the acrylic resin are compatible and a solution without turbidity is obtained, “◯” is indicated. When the elastomer and the acrylic resin are not compatible and the solution is turbid, “X” is indicated. . The results are shown in Table 1.

(Formation of adhesive layer)
Each adhesive composition was spin-coated on a wafer (12-inch Si), and baked at 100 ° C., 160 ° C., and 200 ° C. for 5 minutes each to form an adhesive layer (film thickness 50 μm).

[Affixing of wafer and support]
The wafer and the support (12-inch bare glass) were bonded to each other through the adhesive layer, and a laminate was obtained at a temperature of 215 ° C. and a pressure of 1000 kg for 3 minutes in a reduced pressure environment. The pasting state in the obtained laminate was visually confirmed. If no unbonded portion between the wafer and the support was confirmed, “◯” was indicated, and if an unbonded portion was confirmed, “x” was indicated. The results are shown in Table 1.

[High temperature treatment of laminates]
The laminate was heated at 220 ° C. for 1 hour in a reduced pressure environment (10 Pa). Thereby, the heat resistance of the adhesive composition was evaluated. The heat resistance was evaluated as “◯” when there was no foaming or peeling between the wafer and the support, and “X” when there was no foaming or peeling. The results are shown in Table 1.

  As shown in Table 1, for the adhesive composition of Comparative Example 7, the solution was cloudy and there was no solution stability. Therefore, the evaluation of the pasting state and heat resistance was not performed. -".

  As shown in Table 1, in the examples, in the case of being subjected to the wafer thinning process and the heating and pressurizing process, a sticking failure (unbonded part) that leads to breakage of the wafer or deterioration of in-plane uniformity of the wafer. ) Was not confirmed. On the other hand, in Comparative Examples 1 to 4, an unbonded portion was confirmed. In particular, many unbonded portions were observed inside the edge beat (in the adhesive layer formed by spin coating, the raised portion of the adhesive generated at the edge of the wafer due to surface tension).

  In Examples, foaming or peeling did not occur in the adhesive layer due to heating, but in Comparative Examples 5 and 6, foaming occurred between the wafer and the support due to heating.

  The adhesive composition and adhesive film according to the present invention can be suitably used, for example, in the manufacturing process of a miniaturized semiconductor device.

Claims (12)

An elastomer containing a styrene unit as a constituent unit of the main chain;
An acrylic resin having a 5% thermal weight loss temperature of 280 ° C. or higher ,
The acrylic resin has a weight average molecular weight of 2,000 or more and 70,000 or less,
Content of the said elastomer is 70 weight part or more and 95 weight part or less, 100 weight part of adhesive composition whole quantity is the adhesive composition characterized by the above-mentioned . An elastomer containing a styrene unit as a constituent unit of the main chain;
An acrylic resin having a 5% thermal weight loss temperature of 280 ° C. or higher;
Contains
The acrylic resin has a weight average molecular weight of 2,000 or more and 70,000 or less,
An adhesive composition, wherein the elastomer and the acrylic resin contain decahydronaphthalene as a soluble solvent. An adhesive composition for bonding a wafer and a support plate,
An elastomer containing a styrene unit as a constituent unit of the main chain;
An acrylic resin having a 5% thermal weight loss temperature of 280 ° C. or higher;
Contains
The acrylic resin has a weight average molecular weight of 2,000 or more and 70,000 or less. The adhesive composition according to any one of claims 1 to 3, wherein a content of a styrene unit in the elastomer is 14% by weight or more and 50% by weight or less. The adhesive composition according to any one of claims 1 to 4, wherein the elastomer has a weight average molecular weight of 10,000 or more and 200,000 or less. The said acrylic resin contains a styrene unit as a structural unit, The adhesive composition of any one of Claims 1-5 characterized by the above-mentioned. The adhesive composition according to any one of claims 1 to 6 , wherein the acrylic resin has a solubility parameter of 6 or more and 10 or less.   8. The adhesive composition according to claim 1, wherein the content of the acrylic resin is 1% by weight or more and 50% by weight or less.   The adhesive composition according to claim 1, wherein the elastomer is a hydrogenated product.   The adhesive composition according to any one of claims 1 to 9, wherein both ends of the elastomer are styrene block polymers.   The adhesive composition according to any one of claims 1 to 10, wherein the elastomer is a hydrogenated product of a block copolymer of styrene and a conjugated diene.   An adhesive film comprising an adhesive composition according to any one of claims 1 to 11 formed on a film.