JP2011204793A - Wafer processing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wafer processing method that includes a wafer processing process of executing liquid chemical processing, heating treatment or processing accompanied by heat generation, and is capable of reliably processing a wafer without breakage or the like.SOLUTION: The wafer processing method includes a support plate fixing process of fixing a wafer to a support plate through an adhesive composition containing an adhesive component and a gas generator that generates a gas by stimulation, a wafer processing process of executing liquid chemical processing, heating treatment or processing accompanied by heat generation to the surface of the wafer fixed to the support plate, and a support plate peeling process of peeling the support plate from the wafer by stimulating the wafer after processing and generating a gas from the gas generator.

Description

The present invention relates to a wafer processing method that includes a wafer processing step for performing chemical processing, heat treatment, or heat generation, and that can reliably process the wafer without breakage.

In the semiconductor chip manufacturing process, the wafer is fixed to a support plate in order to facilitate handling during wafer processing and prevent damage. For example, when a thick film wafer cut from a high-purity silicon single crystal or the like is ground to a predetermined thickness to form a thin film wafer, the thick film wafer is bonded to a support plate with an adhesive. .

Adhesives that adhere the wafer to the support plate are required to have high adhesiveness that allows the wafer to be firmly fixed during the processing process, and to be able to be peeled off after the process without damaging the wafer (hereinafter referred to as “high adhesion easy”). Also called “peeling”.)
As an adhesive composition that achieves high adhesion and easy peeling, Patent Document 1 discloses a pressure-sensitive adhesive tape using a photo-curing pressure-sensitive adhesive that is cured by irradiation with light such as ultraviolet rays to reduce the adhesive force. . It is said that such an adhesive tape can reliably fix the semiconductor during the processing step and can be easily peeled off by irradiating ultraviolet rays or the like.

Patent Document 2 discloses a heat-peelable pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer containing thermally expandable microspheres. When the heat-peelable pressure-sensitive adhesive sheet of Patent Document 2 is heated to a certain temperature or more, the thermally expandable microspheres expand, the entire pressure-sensitive adhesive layer is foamed and irregularities are formed on the surface, and the adhesion area with the adherend is reduced. Therefore, it is said that the adherend can be easily peeled off.

Patent Document 3 describes a double-sided pressure-sensitive adhesive tape having an adhesive layer containing a gas generating agent that generates a gas by stimulation with an azo compound or the like. When the double-sided pressure-sensitive adhesive tape of Patent Document 3 is stimulated, gas generated from the gas generating agent is released to the interface between the surface of the tape and the adherend, and at least a part of the adherend is peeled off by the pressure. If the double-sided adhesive tape of patent document 3 is used, it can peel, without damaging a thin film wafer, a semiconductor chip, etc., and without the adhesive residue.

With the recent improvement in performance of semiconductor chips, chemical processing, heat treatment, or heat generation has been performed on the surface of a wafer. For example, three-dimensional stacking technology using TSV (Through Si via) that has dramatically improved the performance of devices by stacking a plurality of semiconductor chips has attracted attention as the next generation technology. . TSV can not only increase the density of semiconductor mounting, but also reduce the noise and resistance by shortening the connection distance. The access speed is dramatically faster and the heat generated during use is excellent. . In manufacturing such a TSV, it is necessary to perform a high-temperature processing process of 200 ° C. or higher, such as bumping a thin film wafer obtained by grinding, bump formation on the back surface, or reflow during three-dimensional lamination. It becomes.
In the processing of a wafer involving such a harsh processing step, the conventional adhesive composition described in Patent Documents 1 to 3 has high adhesive strength and releasability capable of peeling without damaging the wafer after completion of the step. There was a problem that it was not possible to achieve both.

JP-A-5-32946 JP-A-11-166164 JP 2003-231872 A

It is an object of the present invention to provide a wafer processing method that includes a wafer processing step for performing chemical treatment, heat treatment, or heat generation, and that can reliably process the wafer without breakage.

The present invention provides a support plate fixing step of fixing a wafer to a support plate via an adhesive composition containing an adhesive component and a gas generating agent that generates gas upon stimulation, and a wafer fixed to the support plate A wafer processing step for performing chemical treatment, heat treatment or heat generation on the surface of the substrate, and a support plate for peeling the support plate from the wafer by generating a gas from the gas generating agent by stimulating the processed wafer. A wafer processing method having a peeling step.
The present invention is described in detail below.

The wafer processing method of the present invention includes a support plate fixing step of fixing a wafer to a support plate via an adhesive composition containing an adhesive component and a gas generating agent that generates gas upon stimulation.
By fixing the wafer to the support plate, handling can be facilitated during processing, and damage can be prevented.

The adhesive composition contains an adhesive component and a gas generating agent that generates gas upon stimulation.
The adhesive component is not particularly limited, and may contain either a non-curable adhesive or a curable adhesive.
When the adhesive component contains a non-curable adhesive, a gas is generated from the gas generating agent by giving a stimulus to the adhesive composition in a support plate peeling process described later, and the generated gas is softer. The entire adhesive component is foamed to form irregularities on the surface, and the adhesive area with the adherend is reduced and peeled off.
In the case where the adhesive component contains a curable adhesive, gas is generated from the gas generating agent by stimulating the adhesive composition in a support plate peeling step described later, and the generated gas is cured. It is released from the adhesive component to the interface with the adherend, and at least a part of the adherend is peeled by the pressure.
Especially, since reliable peeling can be performed without generating adhesive residue, it is preferable to contain a curable adhesive whose elastic modulus is increased by stimulation.

The non-curable adhesive is not particularly limited. For example, a rubber adhesive, an acrylic adhesive, a vinyl alkyl ether adhesive, a silicone adhesive, a polyester adhesive, a polyamide adhesive, and a urethane adhesive. Agents, styrene / diene block copolymer adhesives, and the like.

The curable adhesive is not particularly limited, and examples thereof include a photocurable adhesive and a thermosetting adhesive containing a polymerizable polymer as a main component and a photopolymerization initiator and a thermal polymerization initiator.
Such photo-curing adhesives and thermosetting adhesives are uniformly and rapidly polymerized and integrated by light irradiation or heating so that the elastic modulus is significantly increased by polymerization curing. Thus, the adhesive strength is greatly reduced. In addition, when gas is generated from the gas generating agent in a hard cured product having an increased elastic modulus, most of the generated gas is released to the outside, and the released gas is released from the adherend to the adhesive surface of the adhesive. Remove at least a portion to reduce the adhesive strength.

The polymerizable polymer is prepared by, for example, previously synthesizing a (meth) acrylic polymer having a functional group in the molecule (hereinafter referred to as a functional group-containing (meth) acrylic polymer) and reacting with the functional group in the molecule. It can obtain by making it react with the compound (henceforth a functional group containing unsaturated compound) which has a functional group to perform and a radically polymerizable unsaturated bond.

The functional group-containing (meth) acrylic polymer is an acrylic having an alkyl group usually in the range of 2 to 18 as a polymer having adhesiveness at room temperature, as in the case of a general (meth) acrylic polymer. By copolymerizing an acid alkyl ester and / or methacrylic acid alkyl ester as a main monomer, a functional group-containing monomer, and, if necessary, another modifying monomer copolymerizable therewith by a conventional method It is obtained. The weight average molecular weight of the functional group-containing (meth) acrylic polymer is usually about 200,000 to 2,000,000.

Examples of the functional group-containing monomer include a carboxyl group-containing monomer such as acrylic acid and methacrylic acid; a hydroxyl group-containing monomer such as hydroxyethyl acrylate and hydroxyethyl methacrylate; and an epoxy group containing glycidyl acrylate and glycidyl methacrylate. Monomers; Isocyanate group-containing monomers such as isocyanate ethyl acrylate and isocyanate ethyl methacrylate; and amino group-containing monomers such as aminoethyl acrylate and aminoethyl methacrylate.

Examples of other modifying monomers that can be copolymerized include various monomers used in general (meth) acrylic polymers such as vinyl acetate, acrylonitrile, and styrene.

The functional group-containing unsaturated compound to be reacted with the functional group-containing (meth) acrylic polymer is the same as the functional group-containing monomer described above according to the functional group of the functional group-containing (meth) acrylic polymer. it can. For example, when the functional group of the functional group-containing (meth) acrylic polymer is a carboxyl group, an epoxy group-containing monomer or an isocyanate group-containing monomer is used, and when the functional group is a hydroxyl group, an isocyanate group-containing monomer is used. When the functional group is an epoxy group, a carboxyl group-containing monomer or an amide group-containing monomer such as acrylamide is used, and when the functional group is an amino group, an epoxy group-containing monomer is used.

Examples of the photopolymerization initiator include those activated by irradiation with light having a wavelength of 250 to 800 nm. Examples of such a photopolymerization initiator include acetophenone derivative compounds such as methoxyacetophenone; Benzoin ether compounds such as benzoin propyl ether and benzoin isobutyl ether; ketal derivative compounds such as benzyldimethyl ketal and acetophenone diethyl ketal; phosphine oxide derivative compounds; bis (η5-cyclopentadienyl) titanocene derivative compounds, benzophenone, Michler's ketone, Chlorothioxanthone, Todecylthioxanthone, Dimethylthioxanthone, Diethylthioxanthone, α-hydroxycyclohexyl phenyl ketone, 2-hydroxymethylphenylpropane, etc. These radical photopolymerization initiators. These photoinitiators may be used independently and 2 or more types may be used together.

Examples of the thermal polymerization initiator include those that decompose by heat and generate active radicals that initiate polymerization and curing, such as dicumyl peroxide, di-t-butyl peroxide, and t-butyl peroxybenzoale. , T-butyl hydroperoxide, benzoyl peroxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide, paramentane hydroperoxide, di-t-butyl peroxide and the like.
However, in order for the adhesive composition of the present invention to exhibit high heat resistance, it is preferable to use a thermal polymerization initiator having a thermal decomposition temperature of 200 ° C. or higher as the thermal polymerization initiator. Examples of the thermal polymerization initiator having a high thermal decomposition temperature include cumene hydroperoxide, paramentane hydroperoxide, di-t-butyl peroxide, and the like.
Although it does not specifically limit as what is marketed among these thermal polymerization initiators, For example, perbutyl D, perbutyl H, perbutyl P, permenta H (all are the NOF Corporation make) etc. are suitable. These thermal polymerization initiators may be used independently and 2 or more types may be used together.

The photocurable adhesive and thermosetting adhesive preferably further contain a radical polymerizable polyfunctional oligomer or monomer. By containing a radically polymerizable polyfunctional oligomer or monomer, photocurability and thermosetting are improved.
The polyfunctional oligomer or monomer preferably has a molecular weight of 10,000 or less, and more preferably has a molecular weight of 5000 or less so that the three-dimensional network of the pressure-sensitive adhesive layer can be efficiently formed by heating or light irradiation. And the number of radically polymerizable unsaturated bonds in the molecule is 2-20.

The polyfunctional oligomer or monomer is, for example, trimethylolpropane triacrylate, tetramethylolmethane tetraacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol monohydroxypentaacrylate, dipentaerythritol hexaacrylate, or the same methacrylate as described above. And the like. Other examples include 1,4-butylene glycol diacrylate, 1,6-hexanediol diacrylate, polypropylene glycol # 700 diacrylate, polyethylene glycol diacrylate, commercially available oligoester acrylate, and methacrylates similar to those described above. These polyfunctional oligomers or monomers may be used alone or in combination of two or more.

Although the said gas generating agent is not specifically limited, The gas generating agent which is not peeled by the chemical | medical solution process mentioned later, heat processing, or the process accompanied by heat_generation | fever, ie, excellent in the tolerance with respect to these processes, is suitable.
As the gas generating agent, for example, a carboxylic acid compound represented by the following general formula (1) or a salt thereof is suitable. Such a gas generating agent generates gas (carbon dioxide gas) by irradiating light such as ultraviolet rays, and has high heat resistance that does not decompose even at a high temperature of about 200 ° C. Moreover, it is excellent also in tolerance with respect to chemical | medical solutions, such as an acid, an alkali, and an organic solvent. Such a gas generating agent does not react to generate a gas even in a severe wafer processing step described later.

In formula (1), R ^{1 to} R ⁷ each represent hydrogen or an organic group. R ^{1 to} R ⁷ may be the same or different. Two of R ^{1 to} R ⁷ may be bonded to each other to form a cyclic structure.

Examples of the organic group in the general formula (1) include an alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group, and an isobutyl group, an alkoxy group such as a methoxy group and an ethoxy group, a carboxyl group, a hydroxyl group, , Aromatic groups such as nitro groups and phenyl groups, polycyclic hydrocarbon groups such as naphthyl groups, fluorenyl groups and pyrenyl groups, ring-assembled hydrocarbon groups such as biphenyl groups, and heterocyclic groups such as xanthenyl groups Etc.
Among them, one of R ^{3 to} R ^{7 in} the above formula (1) is an organic group represented by the following formula (2), or R ^{3 to} R ⁷ in the above formula (1). It is preferable that two adjacent ones are bonded to each other to form a cyclic structure represented by the following formula (3).

In formula (2), R < ⁸ > -R < ¹² > shows hydrogen or an organic group, respectively. R ^{8 to} R ¹² may be the same or different. Two of R ^{8 to} R ¹² may be bonded to each other to form a cyclic structure.
In formula (3), R < ¹³ > -R < ¹⁶ > shows hydrogen or an organic group, respectively. R ^{13 to} R ¹⁶ may be the same or different. Two of R ^{13 to} R ¹⁶ may be bonded to each other to form a cyclic structure.
In addition, R ¹ in the above formula (1) is preferably a methyl group.

Specific examples of the carboxylic acid compound represented by the above formula (1) include, for example, phenylacetic acid, diphenylacetic acid, triphenylacetic acid, 2-phenylpropionic acid, 2,2-diphenylpropionic acid, 2,2,2- Triphenylpropionic acid, 2-phenylbutyric acid, α-methoxyphenylacetic acid, mandelic acid, atrolactone acid, benzylic acid, tropic acid, phenylmalonic acid, phenylsuccinic acid, 3-methyl-2-phenylbutyric acid, orthotoluylacetic acid , Metatoluylacetic acid, 4-isobutyl-α-methylphenylacetic acid, p-toluylacetic acid, 1,2-phenylenediacetic acid, 1,3-phenylenediacetic acid, 1,4-phenylenediacetic acid, 2-methoxyphenylacetic acid, 2-hydroxy Phenylacetic acid, 2-nitrophenylacetic acid, 3-nitrophenylacetic acid, 4-ni Trophenylacetic acid, 2- (4-nitrophenyl) propionic acid, 3- (4-nitrophenyl) propionic acid, 4- (4-nitrophenyl) propionic acid, 3,4-dimethoxyphenylacetic acid, 3,4- ( Methylenedioxy) phenylacetic acid, 2,5-dimethoxyphenylacetic acid, 3,5-dimethoxyphenylacetic acid, 3,4,5-trimethoxyphenylacetic acid, 2,4-dinitrophenylacetic acid, 4-biphenylacetic acid, 1-naphthyl Examples include acetic acid, 2-naphthylacetic acid, 6-methoxy-α-methyl-2-naphthylacetic acid, 1-pyreneacetic acid, 9-fluorenecarboxylic acid, or 9H-xanthene-9-carboxylic acid.

Among these, the carboxylic acid compound represented by the above formula (1) is ketoprofen represented by the following formula (1-1) or 2-xanthone acetic acid represented by the following formula (1-2). preferable.

Since the salt of the carboxylic acid compound represented by the above formula (1) also has a skeleton derived from the carboxylic acid compound represented by the above formula (1), decarboxylation easily occurs when irradiated with light, Carbon dioxide gas can be generated.

The salt of the carboxylic acid compound represented by the above formula (1) can be easily passed through a complicated synthesis route simply by mixing the carboxylic acid compound represented by the above formula (1) and the basic compound in a container. Can be prepared.
The basic compound is not particularly limited, and examples thereof include amines, hydrazine compounds, quaternary ammonium hydroxide salts, and phosphine compounds.
The amine is not particularly limited, and any of primary amines, secondary amines, and tertiary amines can be used.
Among these, the basic compound is preferably a monoalkylamine or a dialkylamine. When monoalkylamine or dialkylamine is used, the polarity of the obtained salt of the carboxylic acid compound represented by the formula (1) can be reduced, and the solubility with the adhesive component can be increased. More preferably, it is a C6-C12 monoalkylamine or dialkylamine.

When the adhesive component contains a curable adhesive whose elastic modulus is increased by stimulation, the carboxylic acid compound represented by the above formula (1) or a salt thereof is preferably dissolved in the adhesive component. . When the carboxylic acid compound represented by the above formula (1) or a salt thereof is dissolved in the adhesive, these compounds themselves do not become the core of foaming, and almost all of the generated gas is covered by the adhesive component. Since it is released to the interface with the adherend, more reliable peeling can be performed. Accordingly, a salt of the carboxylic acid compound represented by the above formula (1) having higher solubility is preferable.

When the functional group-containing (meth) acrylic polymer is used as the adhesive component and the carboxylic acid compound represented by the formula (1) is a ketoprofen represented by the formula (1-1), ketoprofen Both salts thereof have high solubility in the adhesive component.
When the functional group-containing (meth) acrylic polymer is used as the adhesive component, and the carboxylic acid compound represented by the formula (1) is 2-xanthone acetic acid represented by the formula (1-2) The 2-xanthone acetic acid is preferably used as a salt having a low polarity and increased solubility in the adhesive component.

As the gas generating agent, a tetrazole compound represented by the following general formula (4), general formula (5) or general formula (6) or a salt thereof is also suitable. These gas generating agents also generate gas (nitrogen gas) by irradiating light such as ultraviolet rays, and have high heat resistance that does not decompose even at a high temperature of about 200 ° C. Moreover, it is excellent also in the tolerance with respect to chemical | medical solutions, such as an acid, an alkali, and an organic solvent. These gas generating agents do not react and generate gas even in the severe wafer processing steps described later.

In formulas (4) to (6), R ²¹ and R ²² represent hydrogen, an alkyl group having 1 to 7 carbon atoms, an alkylene group, a phenyl group, a mercapto group, a hydroxyl group, or an amino group.

Since the salt of the tetrazole compound represented by the general formulas (4) to (6) also has a skeleton derived from the tetrazole compound represented by the general formulas (4) to (6), light is irradiated. And nitrogen gas can be generated.
The salt of the tetrazole compound represented by the general formulas (4) to (6) is not particularly limited, and examples thereof include a sodium salt, a potassium salt, and an ammonium salt.

The salt of the tetrazole compound represented by the general formulas (4) to (6) can be obtained by simply mixing the tetrazole compound and the basic compound represented by the general formulas (4) to (6) in a container. It can be easily prepared through a complicated synthetic route.
The basic compound is not particularly limited, and examples thereof include amines, hydrazine compounds, quaternary ammonium hydroxide salts, and phosphine compounds.
The amine is not particularly limited, and any of primary amines, secondary amines, and tertiary amines can be used.
Among these, the basic compound is preferably a monoalkylamine or a dialkylamine. When monoalkylamine or dialkylamine is used, the polarity of the resulting salt of the tetrazole compound represented by the general formulas (4) to (6) can be reduced, and the solubility with the adhesive component is increased. be able to. More preferably, it is a C6-C12 monoalkylamine or dialkylamine.

When the adhesive component contains a curable adhesive whose elastic modulus is increased by stimulation, the tetrazole compound represented by the general formulas (4) to (6) or a salt thereof is dissolved in the adhesive component. Preferably it is. By dissolving the tetrazole compound represented by the general formulas (4) to (6) or a salt thereof in the adhesive, these compounds themselves do not become the core of foaming, and almost all of the generated gas is bonded. Since it is released from the agent component to the interface with the adherend, more reliable peeling can be performed. Accordingly, salts of tetrazole compounds represented by the above general formulas (4) to (6) having higher solubility are preferable.

The tetrazole compound represented by the general formula (4) or a salt thereof is not particularly limited, but specifically, for example, 1H-tetrazole, 5-phenyl-1H-tetrazole, 5,5-azobis-1H-tetrazole, 5 -Amino-1H-tetrazole, 5-methyl-1H-tetrazole, 1-methyl-5-mercapto-1H-tetrazole, 1-methyl-5-ethyl-1H-tetrazole, 1- (dimethylaminoethyl) -5-mercapto -1H-tetrazole and the like.

Although the tetrazole compound or its salt represented by the said General formula (5) is not specifically limited, For example, 5,5'-bistetrazole diammonium salt etc. are mentioned.

Although the tetrazole compound or its salt represented by the said General formula (6) is not specifically limited, For example, 5,5'-bistetrazoleamine monoammonium salt etc. are mentioned.

As for the content of the gas generating agent, a preferable lower limit with respect to 100 parts by weight of the adhesive component is 5 parts by weight, and a preferable upper limit is 50 parts by weight. When the content of the gas generating agent is less than 5 parts by weight, generation of carbon dioxide gas or nitrogen gas due to light irradiation is reduced, and sufficient peeling may not be performed. It may not be able to dissolve in the agent component and the adhesive strength may be reduced. The minimum with more preferable content of the said gas generating agent is 10 weight part, and a more preferable upper limit is 30 weight part.

The adhesive composition may contain a photosensitizer.
Since the photosensitizer has an effect of amplifying stimulation by light on the gas generating agent, gas can be released by irradiation with less light. In addition, gas can be emitted by light in a wider wavelength region.

The photosensitizer is not particularly limited as long as it has excellent heat resistance.
Examples of the photosensitizer excellent in heat resistance include polycyclic aromatic compounds having at least one alkoxy group. Among these, a substituted alkoxy polycyclic aromatic compound having an alkoxy group partially substituted with a glycidyl group or a hydroxyl group is preferable. These photosensitizers have high resistance to sublimation and can be used at high temperatures. Moreover, when a part of the alkoxy group is substituted with a glycidyl group or a hydroxyl group, the solubility in the adhesive component is increased, and bleeding out can be prevented.

The polycyclic aromatic compound is preferably an anthracene derivative. The alkoxy group preferably has 1 to 18 carbon atoms, and more preferably has 1 to 8 carbon atoms.

Examples of the polycyclic aromatic compound having at least one alkoxy group include 9,10-dimethoxyanthracene, 2-ethyl-9,10-dimethoxyanthracene, 2-tbutyl-9,10-dimethoxyanthracene, 2, 3-dimethyl-9,10-dimethoxyanthracene, 9-methoxy-10-methylanthracene, 9,10-diethoxyanthracene, 2-ethyl-9,10-diethoxyanthracene, 2-tbutyl-9,10-di Ethoxyanthracene, 2,3-dimethyl-9,10-diethoxyanthracene, 9-ethoxy-10-methylanthracene, 9,10-dipropoxyanthracene, 2-ethyl-9,10-dipropoxyanthracene, 2-tbutyl -9,10-dipropoxyanthracene, 2,3-dimethyl-9, 0-dipropoxyanthracene, 9-isopropoxy-10-methylanthracene, 9,10-dibutoxyanthracene, 9,10-dibenzyloxyanthracene, 2-ethyl-9,10-dibenzyloxyanthracene, 2-tbutyl -9,10-dibenzyloxyanthracene, 2,3-dimethyl-9,10-dibenzyloxyanthracene, 9-benzyloxy-10-methylanthracene, 9,10-di-α-methylbenzyloxyanthracene, 2- Ethyl-9,10-di-α-methylbenzyloxyanthracene, 2-tbutyl-9,10-di-α-methylbenzyloxyanthracene, 2,3-dimethyl-9,10-di-α-methylbenzyloxy Anthracene, 9- (α-methylbenzyloxy) -10-methylanthracase , 9,10-di (2-hydroxyethoxy) anthracene, and the like anthracene derivative such as 2-ethyl-9,10-di (2-carboxyethoxy) anthracene.

The substituted alkoxy polycyclic aromatic compound having an alkoxy group partially substituted with a glycidyl group or a hydroxyl group is, for example, 9,10-di (glycidyloxy) anthracene, 2-ethyl-9,10-di (glycidyloxy). ) Anthracene, 2-tbutyl-9,10-di (glycidyloxy) anthracene, 2,3-dimethyl-9,10-di (glycidyloxy) anthracene, 9- (glycidyloxy) -10-methylanthracene, 9, 10-di (2-vinyloxyethoxy) anthracene, 2-ethyl-9,10-di (2-vinyloxyethoxy) anthracene, 2-tbutyl-9,10-di (2-vinyloxyethoxy) anthracene, 2 , 3-Dimethyl-9,10-di (2-vinyloxyethoxy) anthracene, 9- (2-vinyloxy) Ethoxy) -10-methylanthracene, 9,10-di (3-methyl-3-oxetanylmethoxy) anthracene, 2-ethyl-9,10-di (3-methyl-3-oxetanylmemethoxy) anthracene, 2-t Butyl-9,10-di (3-methyl-3-oxetanylmemethoxy) anthracene, 2,3-dimethyl-9,10-di (3-methyl-3-oxetanylmemethoxy) anthracene, 9- (3-methyl -3-oxetanylmemethoxy) -10-methylanthracene, 9,10-di (p-epoxyphenylmethoxy) anthracene, 2-ethyl-9,10-di (p-epoxyphenylmethoxy) anthracene, 2-tbutyl- 9,10-di (p-epoxyphenylmethoxy) anthracene, 2,3-dimethyl-9,10-di (p-ethylene) Xylphenylmethoxy) anthracene, 9- (p-epoxyphenylmethoxy) -10-methylanthracene, 9,10-di (p-vinylphenylmethoxy) anthracene, 2-ethyl-9,10-di (p-vinylphenylmethoxy) ) Anthracene, 2-tbutyl-9,1-di (p-vinylphenylmethoxy) anthracene, 2,3-dimethyl-9,10-di (p-vinylphenylmethoxy) anthracene, 9- (p-vinylphenylmethoxy) ) -10-methylanthracene, 9,10-di (2-hydroxyethoxy) anthracene, 9,10-di (2-hydroxypropoxy) anthracene, 9,10-di (2-hydroxybutoxy) anthracene, 9,10- Di (2-hydroxy-3-butoxypropoxy) anthracene, 9,10-di (2-Hydroxy-3- (2-ethylhexyloxy) propoxy) anthracene, 9,10-di (2-hydroxy-3-allyloxypropoxy) anthracene, 9,10-di (2-hydroxy-3-phenoxypropoxy) Anthracene, 9,10-di (2,3-dihydroxypropoxy) anthracene, etc. are mentioned.

The content of the photosensitizer is preferably 0.05 parts by weight and preferably 10 parts by weight with respect to 100 parts by weight of the adhesive component. When the content of the photosensitizer is less than 0.05 parts by weight, a sufficient sensitizing effect may not be obtained. When the content exceeds 10 parts by weight, the residue derived from the photosensitizer increases. , Sufficient peeling may not be performed. The minimum with more preferable content of the said photosensitizer is 0.1 weight part, and a more preferable upper limit is 5 weight part.

The adhesive composition suitably contains various polyfunctional compounds that are blended in general pressure-sensitive adhesives such as isocyanate compounds, melamine compounds, and epoxy compounds as needed for the purpose of adjusting the cohesive force as pressure-sensitive adhesives. May be.
The adhesive composition may contain known additives such as a plasticizer, a resin, a surfactant, a wax, and a fine particle filler.

In the support plate fixing step, the wafer and the support plate may be bonded directly by the adhesive composition, or a double-sided pressure-sensitive adhesive tape having an adhesive layer made of the adhesive composition on at least one surface. May be used for bonding.

The double-sided pressure-sensitive adhesive tape may be a support tape having a pressure-sensitive adhesive layer on both sides of the base material, or may be a non-support tape having no base material.
When the double-sided pressure-sensitive adhesive tape is a support tape, the base material is, for example, a sheet or mesh made of a transparent resin such as acrylic, olefin, polycarbonate, vinyl chloride, ABS, polyethylene terephthalate (PET), nylon, urethane, or polyimide. And a sheet having a hole-like structure, a sheet having holes, and the like.

The wafer processing method of the present invention includes a wafer processing step in which chemical treatment, heat treatment, or heat generation is performed on the surface of the wafer fixed to the support plate. As the gas generating agent, a compound represented by the general formula (1) or a salt thereof, a compound represented by the general formula (2) or a salt thereof, or a compound represented by the general formula (3) is used. In such a case, even when such a severe treatment is performed, the gas generating agent does not react and unexpected peeling does not occur.

The said chemical | medical solution process will not be specifically limited if it is a process using an acid, an alkali, or an organic solvent, For example, plating processing, such as electrolytic plating and electroless plating, hydrofluoric acid, tetramethylammonium hydroxide aqueous solution (TMAH) etc. Examples include a wet etching process, a resist stripping process using N-methyl-2-pyrrolidone, monoethanolamine, DMSO, and a cleaning process using concentrated sulfuric acid, aqueous ammonia, hydrogen peroxide, and the like.

Examples of the heat treatment or treatment accompanied by heat generation include sputtering, vapor deposition, etching, chemical vapor deposition (CVD), physical vapor deposition (PVD), resist coating / patterning, and reflow.

The wafer processing step of the present invention may include a dicing tape attaching step of attaching a dicing tape to the processed surface of the wafer after the above processing prior to a support plate peeling step described later. By sticking a dicing tape in advance, after the support plate is peeled off in the support plate peeling step, the dicing step can be promptly performed.

The wafer processing method of the present invention includes a support plate peeling step for stimulating the processed wafer to generate gas from the gas generating agent and peeling the support plate from the wafer.
When the adhesive composition for bonding the wafer and the support plate contains a gas generating agent, the wafer can be easily peeled from the support plate without damaging the wafer by giving a stimulus.

According to the present invention, it is possible to provide a wafer processing method that includes a wafer processing step for performing a chemical treatment, a heat treatment, or a process involving heat generation, and that can reliably process the wafer without being damaged.

Hereinafter, embodiments of the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples.

Example 1
A reactor equipped with a thermometer, a stirrer, and a cooling tube was prepared, and in this reactor, 94 parts by weight of 2-ethylhexyl acrylate, 1 part by weight of acrylic acid, 5 parts by weight of 2-hydroxyethyl acrylate, lauryl mercapcaptan 0 After adding 0.01 parts by weight and 180 parts by weight of ethyl acetate, the reactor was heated to start refluxing. Subsequently, 0.01 parts by weight of 1,1-bis (t-hexylperoxy) -3,3,5-trimethylcyclohexane was added as a polymerization initiator in the reactor, and polymerization was started under reflux. It was. Next, after 1 hour and 2 hours from the start of polymerization, 0.01 parts by weight of 1,1-bis (t-hexylperoxy) -3,3,5-trimethylcyclohexane was added, and the polymerization was started. 4 hours later, 0.05 part by weight of t-hexylperoxypivalate was added to continue the polymerization reaction. And 8 hours after the start of polymerization, an acrylic copolymer having a solid content of 55% by weight and a weight average molecular weight of 600,000 was obtained.
The resin solid content of 100 parts by weight of the ethyl acetate solution containing the acrylic copolymer thus obtained is reacted by adding 3.5 parts by weight of 2-isocyanatoethyl methacrylate, and further the resin of the ethyl acetate solution after the reaction. 0.1 parts by weight of a photopolymerization initiator (Esacure One, manufactured by Nippon Shibel Hegner) and 2.5 parts by weight of a polyisocyanate-based crosslinking agent (Coronate L45, manufactured by Nippon Polyurethane) are mixed and bonded to 100 parts by weight of solid content. An ethyl acetate solution of agent (1) was prepared.

20 parts by weight of ketoprofen (manufactured by Tokyo Chemical Industry Co., Ltd.) and 1 part by weight of 9,10-diglycidyloxyanthracene as a photosensitizer are mixed with 100 parts by weight of the resin solid content of the ethyl acetate solution of the adhesive (1). Thus, an adhesive composition was obtained.

The obtained adhesive composition was coated with a doctor knife on the corona-treated surface of a transparent polyethylene terephthalate film having a thickness of 50 μm, which was corona-treated on one side, so that the thickness of the dry film was 30 μm. The coating solution was dried by heating at 110 ° C. for 5 minutes. Thereafter, static curing was performed at 40 ° C. for 3 days to obtain an adhesive tape.

(Example 2)
Adhesive as in Example 1 except that 1 part by weight of 9,10-bis (2-hydroxypropoxy) anthracene was blended as a photosensitizer instead of 1 part by weight of 9,10-diglycidyloxyanthracene. A composition and an adhesive tape were obtained.

(Example 3)
Adhesive composition and adhesive tape as in Example 1 except that 1 part by weight of 9,10-dibutoxyanthracene was blended in place of 1 part by weight of 9,10-diglycidyloxyanthracene as a photosensitizer. Got.

Example 4
An adhesive composition and an adhesive tape were obtained in the same manner as in Example 1 except that 20 parts by weight of 2-xanthone acetic acid was added instead of 20 parts by weight of ketoprofen.

(Example 5)
An adhesive composition and an adhesive tape were obtained in the same manner as in Example 1 except that 20 parts by weight of 2-xanthone acetate distearylamine salt was blended in place of 20 parts by weight of ketoprofen.

(Example 6)
An adhesive composition and an adhesive tape were obtained in the same manner as in Example 1 except that 20 parts by weight of 5,5′-bistetrazole diammonium salt (manufactured by Masuda Chemical Co., Ltd.) was blended instead of 20 parts by weight of ketoprofen.

(Example 7)
An adhesive composition and an adhesive tape were obtained in the same manner as in Example 1 except that 20 parts by weight of 5,5′-bistetrazoleamine monoammonium salt (Masuda Chemical Co., Ltd.) was blended in place of 20 parts by weight of ketoprofen. .

(Example 8)
An adhesive composition and an adhesive tape were obtained in the same manner as in Example 1 except that 20 parts by weight of 5-phenyl-1H-tetrazole (manufactured by Toyo Kasei Kogyo Co., Ltd.) was blended instead of 20 parts by weight of ketoprofen.

Example 9
An adhesive composition and an adhesive tape were obtained in the same manner as in Example 1 except that 20 parts by weight of 5,5-azobis-1H-tetrazole (manufactured by Toyo Kasei Kogyo Co., Ltd.) was blended instead of 20 parts by weight of ketoprofen.

(Example 10)
An adhesive composition and an adhesive tape were obtained in the same manner as in Example 1 except that 20 parts by weight of 1H-tetrazole (manufactured by Toyo Kasei Kogyo) was blended instead of 20 parts by weight of ketoprofen.

(Example 11)
An adhesive composition and an adhesive tape were obtained in the same manner as in Example 1 except that 20 parts by weight of 5-amino-1H-tetrazole (manufactured by Toyo Kasei Kogyo Co., Ltd.) was blended instead of 20 parts by weight of ketoprofen.

(Example 12)
An adhesive composition and an adhesive tape were obtained in the same manner as in Example 1 except that 20 parts by weight of 5-methyl-1H-tetrazole (manufactured by Toyo Kasei Kogyo Co., Ltd.) was blended instead of 20 parts by weight of ketoprofen.

(Example 13)
The adhesive composition and the adhesive tape were prepared in the same manner as in Example 1 except that 20 parts by weight of 1-methyl-5-mercapto-1H-tetrazole (manufactured by Toyo Kasei Kogyo Co., Ltd.) was blended instead of 20 parts by weight of 5 ketoprofen. Obtained.

(Example 14)
An adhesive composition and an adhesive tape were obtained in the same manner as in Example 1 except that 20 parts by weight of 1-methyl-5-ethyl-1H-tetrazole (manufactured by Toyo Kasei Kogyo Co., Ltd.) was blended instead of 20 parts by weight of ketoprofen. It was.

(Example 15)
In the same manner as in Example 1 except that 20 parts by weight of 1- (dimethylaminoethyl) -5-mercapto-1H-tetrazole (manufactured by Toyo Kasei Kogyo Co., Ltd.) was blended instead of 20 parts by weight of ketoprofen, An adhesive tape was obtained.

(Comparative Example 1)
An adhesive composition and an adhesive tape were obtained in the same manner as in Example 1 except that no gas generating agent was added.

(Comparative Example 2)
Instead of 20 parts by weight of ketoprofen, 20 parts by weight of 2,2′-azobis- (N-butyl-2-methylpropionamide) and 3 parts by weight of diethylthioxanthone instead of 1 part by weight of 9,10-diglycidyloxyanthracene An adhesive composition and an adhesive tape were obtained in the same manner as in Example 1 except that they were blended.

(Comparative Example 3)
A terpene tackifier 15 is added to a toluene solution containing 100 parts by weight of an acrylic copolymer obtained by copolymerizing a monomer mixture consisting of 50 parts by weight of butyl acrylate, 50 parts by weight of ethyl acrylate and 5 parts by weight of acrylic acid. An acrylic pressure-sensitive adhesive was obtained by blending 5 parts by weight of a polyurethane crosslinking agent with 5 parts by weight.
Microsphere F-50D (made by Matsumoto Yushi Co., Ltd.) 50 weight part was mixed with 100 weight part (solid content) of the obtained acrylic adhesive, and the adhesive composition was obtained.
The obtained adhesive composition was coated with a doctor knife on the corona-treated surface of a transparent polyethylene terephthalate film having a thickness of 100 μm with one side corona-treated so that the dry film thickness was about 38 μm. The coating solution was dried by heating at 110 ° C. for 5 minutes. Thereafter, static curing was performed at 40 ° C. for 3 days to obtain an adhesive tape.

(Evaluation)
The adhesive tapes obtained in Examples and Comparative Examples were evaluated by the following methods.
The results are shown in Table 1.

(1) Adhesive evaluation, peelability evaluation An adhesive tape cut into a circle having a diameter of 20 cm was attached to a silicon wafer having a diameter of 20 cm and a thickness of about 750 μm.
As an adhesive evaluation, when the adhesive tape was pulled in this state and was not peeled at all, “x”, when it was relatively lightly peeled, “△”, when it was peeled almost without resistance, “○”. evaluated.

Next, using an ultrahigh pressure mercury lamp from the glass plate side, irradiation with 365 nm ultraviolet rays was performed for 2 minutes while adjusting the illuminance so that the irradiation intensity on the surface of the glass plate was 40 mW / cm ² . As the peelability evaluation after UV irradiation, the case where the adhesive tape was pulled and could be peeled without any resistance was indicated as `` ○ '', the case where there was resistance but could be peeled as `` △ '', and the case where no peeling was possible. “×”.

(2) Evaluation of heat resistance An adhesive tape cut into a circle having a diameter of 20 cm was attached to a silicon wafer having a diameter of 20 cm and a thickness of about 750 μm. The laminate was heated at 200 ° C. for 1 hour and then returned to room temperature.
About the laminated body after a heating, said adhesive evaluation and peelability evaluation were performed.

(3) Evaluation of chemical resistance An adhesive tape cut into a circle having a diameter of 20 cm was attached to a silicon wafer having a diameter of 20 cm and a thickness of about 750 μm. This laminate was immersed in an aqueous hydrochloric acid solution adjusted to pH 4 at 80 ° C. for 2 hours and then dried. About the laminated body after an acid treatment, said adhesive evaluation and peelability evaluation were performed.
Similarly, after immersion in an aqueous sodium hydroxide solution adjusted to pH 12 at 80 ° C. for 2 hours and after immersion in an aqueous tetramethylammonium hydroxide solution (TMAH) at 60 ° C. for 1 hour, evaluation of adhesion and peelability Evaluation was performed.

According to the present invention, it is possible to provide a wafer processing method that includes a wafer processing step for performing a chemical treatment, a heat treatment, or a process involving heat generation, and that can reliably process the wafer without being damaged.

Claims (10)

A support plate fixing step of fixing the wafer to the support plate via an adhesive composition containing an adhesive component and a gas generating agent that generates gas upon stimulation; and a chemical solution on the surface of the wafer fixed to the support plate A wafer processing step for performing a process, a heat treatment or a process involving heat generation, and a support plate peeling step for stimulating the processed wafer to generate gas from the gas generating agent and peeling the support plate from the wafer. A wafer processing method comprising: 2. The wafer processing method according to claim 1, wherein the gas generating agent is a carboxylic acid compound represented by the following general formula (1) or a salt thereof.

In formula (1), R ^{1 to} R ⁷ each represent hydrogen or an organic group. R ^{1 to} R ⁷ may be the same or different. Two of R ^{1 to} R ⁷ may be bonded to each other to form a cyclic structure. One of R ^{3 to} R ^{7 in} the general formula (1) is an organic group represented by the following general formula (2), or among R ^{3 to} R ^{7 in} the general formula (1) 3. The wafer processing method according to claim 2, wherein two adjacent ones of each other are bonded to each other to form an annular structure represented by the following general formula (3).

In formula (2), R < ⁸ > -R < ¹² > shows hydrogen or an organic group, respectively. R ^{8 to} R ¹² may be the same or different. Two of R ^{8 to} R ¹² may be bonded to each other to form a cyclic structure.
In formula (3), R < ¹³ > -R < ¹⁶ > shows hydrogen or an organic group, respectively. R ^{13 to} R ¹⁶ may be the same or different. Two of R ^{13 to} R ¹⁶ may be bonded to each other to form a cyclic structure. 4. The wafer processing method according to claim 2, wherein R ¹ in the general formula (1) is a methyl group. The carboxylic acid compound represented by the general formula (1) is ketoprofen represented by the following formula (1-1) or 2-xanthone acetic acid represented by the following formula (1-2), The wafer processing method according to claim 2, 3 or 4.

2. The wafer processing method according to claim 1, wherein the gas generating agent is a tetrazole compound represented by the following general formula (4), general formula (5) or general formula (6) or a salt thereof.

In formulas (4) to (6), R ²¹ and R ²² represent hydrogen, an alkyl group having 1 to 7 carbon atoms, an alkylene group, a phenyl group, a mercapto group, a hydroxyl group, or an amino group. The wafer processing method according to claim 1, wherein the adhesive component is a photocurable adhesive or a thermosetting adhesive. In the support plate fixing step, the wafer is supported on the support plate using a double-sided pressure-sensitive adhesive tape having an adhesive layer composed of an adhesive composition containing an adhesive component and a gas generating agent that generates gas upon stimulation on at least one surface. 8. The wafer processing method according to claim 1, wherein the wafer processing method is fixed. 9. The wafer processing method according to claim 1, wherein the chemical processing is processing using an acid, an alkali, or an organic solvent. 2. The heat treatment or the treatment accompanied by heat generation is sputtering, vapor deposition, etching, chemical vapor deposition (CVD), physical vapor deposition (PVD), resist coating / patterning, or reflow. 2. The wafer processing method according to 2, 3, 4, 5, 6, 7, 8, or 9.