KR20230147744A - Method for manufacturing semiconductor chip - Google Patents

Abstract

The present invention is a method of manufacturing a semiconductor chip by dicing a wafer in a state reinforced with a dicing tape. Even when an aqueous organic solvent is used, positional misalignment, etc. do not occur, and further, the semiconductor chip obtained The purpose is to provide a method for manufacturing a semiconductor chip that does not cause adhesion of residues. The present invention provides a dicing tape attaching step for reinforcing a dicing tape composed of a base film and an adhesive layer containing at least a curable adhesive component that crosslinks and hardens upon stimulation, by attaching the dicing tape to a wafer from the adhesive layer side, and attaching a dicing tape to the adhesive layer. A pressure-sensitive adhesive layer curing process of crosslinking and curing the curable adhesive component by applying stimulation, a dicing process of obtaining a semiconductor chip by dicing the wafer reinforced by the dicing tape, and a semiconductor process of peeling the semiconductor chip from the dicing tape. This is a method of manufacturing a semiconductor chip having a chip peeling process.

Description

Method for manufacturing semiconductor chips {METHOD FOR MANUFACTURING SEMICONDUCTOR CHIP}

The present invention is a method of manufacturing a semiconductor chip by dicing a wafer in a state reinforced with a dicing tape. Even when an aqueous organic solvent is used, there is no case of misalignment, and there is no residue on the obtained semiconductor chip. It relates to a method of manufacturing a semiconductor chip in which adhesion does not occur.

A semiconductor chip is usually made by slicing a high-purity, rod-shaped semiconductor single crystal, etc. into a wafer, then forming a predetermined circuit pattern on the surface of the wafer using photoresist, then grinding the back side of the wafer with a grinder, and finally grinding it with a grinder. It is manufactured by dicing and turning it into chips.

Conventionally, during dicing, a dicing tape is attached to the back side of a wafer, the wafer is diced in the vertical and horizontal directions while being adhesively fixed, and the resulting semiconductor chips are separated into individual semiconductor chips. A method of picking up the dicing tape by pushing it up with a needle from the dicing tape side and fixing it on the die pad was adopted. For example, in Patent Document 1, using a grinding device having a plurality of grinding wheel axes, a process of grinding the wafer thickness thinly with at least one grinding wheel axis from the back side of the wafer, and grinding the wafer with at least one grinding wheel axis. A wafer grinding method has been disclosed in which the wafer is simultaneously cut and separated into rectangular shapes. However, even in this method, a dicing tape is used to prevent the wafer from being misaligned.

In order to reliably prevent wafer misalignment during dicing, the dicing tape that secures the wafer is required to have high adhesive strength. Additionally, during dicing, an aqueous organic solvent such as an aqueous isopropyl alcohol solution may be sprayed on the surface of the wafer to remove cutting debris. Therefore, dicing tapes are also required to have chemical resistance to water-based organic solvents. However, when the adhesive strength of the dicing tape is increased and chemical resistance is provided, there is a problem that when the semiconductor chip obtained from the dicing tape is peeled off, residue resulting from the dicing tape may adhere to the surface of the semiconductor chip. . This problem of residue adhesion tended to become more noticeable as time passed after the dicing tape was attached to the wafer.

Japanese Patent Publication No. 7-78793

In view of the current situation, the present invention is a method of manufacturing a semiconductor chip by dicing a wafer while reinforced with a dicing tape. Even when using an aqueous organic solvent, positional misalignment does not occur, Additionally, the object is to provide a method for manufacturing a semiconductor chip in which residue does not occur on the obtained semiconductor chip.

The present invention provides a dicing tape attaching step for reinforcing a dicing tape composed of a base film and an adhesive layer containing at least a curable adhesive component that crosslinks and hardens upon stimulation, by attaching the dicing tape to a wafer from the adhesive layer side, and attaching a dicing tape to the adhesive layer. A pressure-sensitive adhesive layer curing process of crosslinking and curing the curable adhesive component by applying stimulation, a dicing process of obtaining a semiconductor chip by dicing the wafer reinforced by the dicing tape, and a semiconductor process of peeling the semiconductor chip from the dicing tape. This is a method of manufacturing a semiconductor chip having a chip peeling process.

The present invention is described in detail below.

As a result of careful study, the present inventors used a dicing tape composed of a base film and an adhesive layer containing a curable adhesive component that crosslinks and hardens upon stimulation, and attached the dicing tape to the wafer in an uncured state. By crosslinking and curing by stimulating it after sticking and before the dicing process, even when using an aqueous organic solvent, there is no case of misalignment, and there is no case of residue adhering to the wafer on the obtained semiconductor chip. Thus, the present invention was completed.

Since the adhesive layer containing a curable adhesive component that crosslinks and hardens upon stimulation has sufficient flexibility before crosslinking and curing the curable adhesive component, a dicing tape using this has irregularities on the surface (e.g., Even if the wafer has irregularities (protruding electrodes, etc.) of 20 ㎛ or more in height, it can reliably follow the irregularities and exhibit high adhesion that can protect the wafer by attaching it to the wafer. In addition, because the adhesive layer is crosslinked and cured in this way, positional misalignment, etc. do not occur even when an aqueous organic solvent is used in the dicing process. Additionally, because the adhesive layer is crosslinked and cured, increased adhesion does not occur, and the semiconductor chip can be peeled from the dicing tape without adhesion of residue.

Additionally, in the semiconductor chip manufacturing method, a wafer processing step in which a treatment involving heating is performed on a wafer reinforced with a dicing tape before the dicing step may be performed. In such a wafer processing process, heating may cause the adhesive layer of the dicing tape to shrink, causing the wafer to bend, or adhesion may increase, causing significant adhesion of residues to the surface of the semiconductor chip. In the semiconductor chip manufacturing method of the present invention, even when such a wafer processing step is performed, the occurrence of warpage or attachment of residues to the surface of the semiconductor chip can be prevented by crosslinking and curing the curable adhesive component before the wafer processing step. there is.

In the semiconductor chip manufacturing method of the present invention, first, a dicing tape consisting of an adhesive layer containing a curable adhesive component that crosslinks and hardens at least by stimulation and a base film is attached to the wafer from the adhesive layer side to reinforce the dicing tape. Perform the sticking process.

The wafer is a raw material for semiconductor chips, and is not particularly limited, and conventionally known wafers can be used. In addition, in this specification, wafers also include wafer-level packages, that is, wafers that are completed by processing from the wafer state to the final package process.

Among these, the present invention is particularly effective for wafers having irregularities on the surface of 20 μm or more in height.

The dicing tape has at least an adhesive layer and a base film.

The adhesive layer contains a curable adhesive component that crosslinks and hardens upon stimulation. By using an adhesive layer containing such a curable adhesive component, the dicing tape can be attached to the wafer with high adhesive strength, and even when an aqueous organic solvent is used, high adhesiveness is achieved without misalignment, etc., and no residue is left behind. It is compatible with high non-residual adhesion that allows the semiconductor chip to be peeled from the dicing tape without sticking.

Stimuli that crosslink and harden the curable adhesive component include light, heat, electromagnetic waves, electron beams, and ultrasonic waves. Among them, a photocurable adhesive component that crosslinks and hardens by irradiation with ultraviolet rays is preferable.

Examples of the photocurable adhesive component include a photocurable adhesive containing a polymerizable polymer as a main component and a photopolymerization initiator.

The polymerizable polymer is, for example, synthesized in advance as a (meth)acrylic polymer having a functional group in the molecule (hereinafter referred to as a (meth)acrylic polymer containing a functional group), and then radically polymerized with a functional group that reacts with the above-described functional group in the molecule. It can be obtained by reacting with a compound having a sexually unsaturated bond (hereinafter referred to as a functional group-containing unsaturated compound).

The functional group-containing (meth)acrylic polymer is a polymer that has adhesiveness at room temperature, and, as in the case of general (meth)acrylic polymers, is an alkyl acrylic acid ester and/or an alkyl group whose carbon number is usually in the range of 2 to 18. It is obtained by using alkyl methacrylate as the main monomer and copolymerizing it with a functional group-containing monomer and, if necessary, other monomers for modification that can be copolymerized with these by a conventional method. The weight average molecular weight of the functional group-containing (meth)acrylic polymer is usually about 200,000 to 2 million.

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

Other monomers for modification that can be copolymerized include, for example, various monomers used in general (meth)acrylic polymers such as vinyl acetate, acrylonitrile, and styrene.

As the functional group-containing unsaturated compound to be reacted with the functional group-containing (meth)acrylic polymer, the same as the functional group-containing monomer described above can be used depending on the functional group of the functional group-containing (meth)acrylic polymer. 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 same 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.

The polymerizable polymer has a preferable lower limit of 0.01 meq/g and a preferable upper limit of the content of radically polymerizable unsaturated bonds of 2.0 meq/g. If the content of the radically polymerizable unsaturated bond of the polymerizable polymer is within this range, the pressure-sensitive adhesive layer after crosslinking and curing the curable pressure-sensitive adhesive component by stimulating the pressure-sensitive adhesive layer in the pressure-sensitive adhesive layer curing step is aqueous in the dicing step. Even when an organic solvent is used, positional misalignment does not occur and the wafer can be sufficiently protected. A more preferable lower limit of the content of radically polymerizable unsaturated bonds in the polymerizable polymer is 0.05 meq/g, and a more preferable upper limit is 1.5 meq/g.

When the curable adhesive component is a photocurable adhesive component, the photopolymerization initiator to be blended may be one that is activated by irradiating light with a wavelength of 250 to 800 nm, for example. Examples of such photopolymerization initiators include: For example, acetophenone derivative compounds such as methoxyacetophenone, benzoin ether-based compounds such as benzoin propyl ether and benzoin isobutyl ether, ketal derivative compounds such as benzyl dimethyl ketal and acetophenone diethyl ketal, Phosphine oxide derivative compounds, bis(η5-cyclopentadienyl)titanocene derivative compounds, benzophenone, Michler's ketone, chlorothioxanthone, dodecylthioxanthone, dimethylthioxanthone, diethylthioxanthone, α -Photo radical polymerization initiators such as hydroxycyclohexylphenylketone and 2-hydroxymethylphenylpropane can be mentioned. These photopolymerization initiators may be used individually, or two or more types may be used together.

The curable adhesive component preferably further contains a radically polymerizable multifunctional oligomer or monomer. By containing a radically polymerizable multifunctional oligomer or monomer, curability when stimulated is improved.

The polyfunctional oligomer or monomer preferably has a molecular weight of 10,000 or less, and more preferably has a molecular weight of 5,000 or less and has a radical polymerizability within the molecule so that the three-dimensional network of the curing component by heating or irradiation with light can be efficiently formed. The number of unsaturated bonds is 2 to 20.

The multifunctional oligomer or monomer is, for example, trimethylolpropane triacrylate, tetramethylolmethane tetraacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, and dipentaerythritol monohydroxypentaacrylate. salt, dipentaerythritol hexaacrylate, or the same methacrylates as mentioned above. In addition, 1,4-butylene glycol diacrylate, 1,6-hexanediol diacrylate, polypropylene glycol #700 diacrylate, polyethylene glycol diacrylate, commercially available oligoester acrylate, and the same methacrylic as above. Rates, etc. can be mentioned. These polyfunctional oligomers or monomers may be used individually, or two or more types may be used together.

The adhesive layer may further contain a gas generating agent that generates gas upon stimulation. When the pressure-sensitive adhesive layer contains the gas-generating agent, in the semiconductor chip peeling process, the pressure-sensitive adhesive layer is stimulated to generate gas from the gas-generating agent, thereby enabling the wafer to be more easily processed without adhesive remaining. The dicing tape can be peeled from.

Here, the curable adhesive component and the gas generator are selected in combination where the stimulus for crosslinking and curing the curable adhesive component and the stimulus for generating gas from the gas generator are qualitatively or quantitatively different. By selecting such a combination, it is possible to prevent gas from being generated from the gas generator due to stimulation in the pressure-sensitive adhesive layer curing process, causing the wafer and the dicing tape to separate.

Specifically, for example, when using the photo-curable adhesive component, a gas generating agent that generates gas by stimulation other than light, such as heat, may be selected. In addition, even if the stimulus that generates gas from the gas generator is light, the wavelength is different from the light that crosslinks and cures the photocurable adhesive component, or even if the wavelength overlaps, the amount of light that crosslinks and cures the photocurable adhesive component is greater than the amount of light that crosslinks and cures the photocurable adhesive component. Select a gas generator that requires a large amount of light.

For example, as a photocurable adhesive component that is crosslinked and cured by irradiation with light, an adhesive containing a polymer having an unsaturated double bond such as a vinyl group in the side chain and a photopolymerization initiator activated at a wavelength of 250 to 800 nm. When used, crosslinking and curing can be achieved by irradiating light with a wavelength of 365 nm or more. When such a photocurable adhesive component is combined with a gas generator that generates gas by irradiating light with a wavelength of 300 nm or less, light with a wavelength of 365 nm or more is irradiated in the adhesive layer curing process, and the semiconductor chip peeling process is performed. In this case, it becomes possible to irradiate light with a wavelength of 300 nm or less.

The gas generating agent is not particularly limited, and for example, conventionally known gas generating agents such as azo compounds and azide compounds can be used.

Moreover, since it has particularly excellent heat resistance, a carboxylic acid compound represented by the following general formula (1) or a salt thereof is also preferable. Such a gas generating agent generates gas (carbon dioxide gas) by irradiating light such as ultraviolet rays, and has high heat resistance so that it does not decompose even when heat is generated during the dicing process.

[Formula 1]

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.

The organic group in the general formula (1) is, for example, an alkyl group such as a methyl group, ethyl group, propyl group, butyl group, or isobutyl group, an alkoxy group such as a methoxy group or an ethoxy group, a carboxyl group, a hydroxyl group, Examples include aromatic groups such as nitro group and phenyl group, polycyclic hydrocarbon groups such as naphthyl group, fluorenyl group, and pyrenyl group, ring-assembly hydrocarbon groups such as biphenyl group, and heterocyclic groups such as xanthenyl group.

Among them, one of R ³ to R ⁷ in the formula (1) is an organic group represented by the formula (2), or two adjacent R ³ to R ⁷ in the formula (1) are bonded to each other. It is preferable to form a cyclic structure represented by the following formula (3).

[Formula 2]

In formula (2), R ⁸ to R ¹² each represent hydrogen or an organic group. 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 ring-like structure.

In formula (3), R ¹³ to R ¹⁶ each represent hydrogen or an organic group. 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.

Moreover, R ¹ in the above formula (1) is preferably a methyl group.

Specific examples of the carboxylic acid compound represented by the 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, atrolactonic acid, benzilic acid, tropic acid, phenylmalonic acid, phenylsuccinic acid, 3-methyl-2-phenylbutyric acid, orthotol. Ruyl acetic acid, metatoluyl acetic acid, 4-isobutyl-α-methylphenylacetic acid, p-toluyl acetic acid, 1,2-phenylene diacetic acid, 1,3-phenylene diacetic acid, 1,4-phenylene diacetic acid, 2-mer Toxyphenylacetic acid, 2-hydroxyphenylacetic acid, 2-nitrophenylacetic acid, 3-nitrophenylacetic acid, 4-nitrophenylacetic 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-naphthylacetic acid, 2-naphthylacetic acid, 6-methoxy-α-methyl-2-naphthyl Acetic acid, 1-pyreneacetic acid, 9-fluorenecarboxylic acid, or 9H-xanthene-9-carboxylic acid can be mentioned.

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

[Formula 3]

Since the carboxylic acid compound represented by the above formula (1) has a salinity and a skeleton derived from the carboxylic acid compound represented by the above formula (1), decarboxylation easily occurs when light is irradiated to generate carbon dioxide gas. You can.

The salt of the carboxylic acid compound represented by the formula (1) can be easily prepared without going through a complicated synthetic route by simply mixing the carboxylic acid compound represented by the formula (1) and the basic compound in a container.

The basic compound is not particularly limited, but examples 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 them, the basic compound is preferably monoalkylamine or dialkylamine. When monoalkylamine or dialkylamine is used, the polarity of the resulting salt of the carboxylic acid compound represented by formula (1) can be lowered, and solubility with the adhesive component can be improved. More preferably, it is a monoalkylamine or dialkylamine having 6 to 12 carbon atoms.

The gas generating agent is also preferably a tetrazole compound or a salt thereof represented by the following general formula (4), (5) or (6). These gas generating systems generate gas (nitrogen gas) by irradiating light such as ultraviolet rays, and have high heat resistance so that they do not decompose even when heat is generated during the dicing process.

[Formula 4]

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.

Due to the salinity of the tetrazole compounds represented by the general formulas (4) to (6) above and the fact that they have a skeleton derived from the tetrazole compounds represented by the above general formulas (4) to (6), nitrogen gas is generated when light is irradiated. You can do it.

The salt of the tetrazole compound represented by the general formulas (4) to (6) is not particularly limited, and examples include sodium salt, potassium salt, and ammonium salt.

The salts of the tetrazole compounds represented by the general formulas (4) to (6) above do not go through a complicated synthetic route by simply mixing the tetrazole compounds represented by the above general formulas (4) to (6) and a basic compound in a container. It can be prepared simply.

The basic compound is not particularly limited, but examples 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 monoalkylamine or 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 to low polarity, and solubility with the photocurable adhesive component can be improved. More preferably, it is a monoalkylamine or dialkylamine having 6 to 12 carbon atoms.

The tetrazole compound or its salt represented by the general formula (4) is not particularly limited, but specifically includes, 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, etc. can be mentioned.

The tetrazole compound or its salt represented by the general formula (5) is not particularly limited, but specific examples include 5,5'-bistetrazole ammonium salt.

The tetrazole compound or its salt represented by the general formula (6) is not particularly limited, but specific examples include 5,5'-bistetrazolamine monoammonium salt.

The content of the gas generator has a preferable lower limit of 5 parts by weight and a preferable upper limit of 50 parts by weight relative to 100 parts by weight of the curable adhesive component. If the content of the gas generator is less than 5 parts by weight, sufficient peeling may not be possible because the generation of carbon dioxide gas or nitrogen gas due to stimulation is reduced, and if it exceeds 50 parts by weight, it may not be completely dissolved in the curable adhesive component and the adhesive strength may be reduced. There are cases where this deteriorates. The more preferable lower limit of the content of the gas generating agent is 10 parts by weight, and the more preferable upper limit is 30 parts by weight.

The adhesive layer may further contain a photosensitizer.

Since the photosensitizer has the effect of amplifying the stimulation of the gas generating agent by light, gas can be released by irradiation of less light. Additionally, gas can be released by light in a wider wavelength range.

The photosensitizer is not particularly limited as long as it has excellent heat resistance.

Examples of photosensitizers with excellent heat resistance include polycyclic aromatic compounds having at least one alkoxy group. Among them, substituted alkoxy polycyclic aromatic compounds having an alkoxy group partially substituted with a glycidyl group or a hydroxyl group are preferable. These photosensitizers have high sublimation resistance and can be used at high temperatures. In addition, by substituting part of the alkoxy group with a glycidyl group or a hydroxyl group, solubility in the photocurable adhesive component increases and bleed-out can be prevented.

The content of the photosensitizer has a preferable lower limit of 0.05 parts by weight and a preferable upper limit of 10 parts by weight based on 100 parts by weight of the curable adhesive component. If the content of the photosensitizer is less than 0.05 parts by weight, sufficient sensitization effect may not be obtained, and if it exceeds 10 parts by weight, the amount of residue derived from the photosensitizer increases and sufficient peeling may not be possible. . The more preferable lower limit of the content of the photosensitizer is 0.1 parts by weight, and the more preferable upper limit is 5 parts by weight.

The adhesive layer may contain fumed silica. By mixing fumed silica, the cohesion of the adhesive layer is increased. For this reason, even if additives with different polarities are mixed with the functional group-containing (meth)acrylic polymer, they do not separate, and the adhesive layer can be made uniform.

The lower limit of the average particle diameter of the fumed silica is 0.05 ㎛, and the upper limit is 3 ㎛. When the average particle diameter of the fumed silica is within this range, it can exhibit high heat resistance in which no lifting occurs even in the metal deposition process and high adhesive non-residual property in which no adhesive remains in the peeling process. The preferable lower limit of the average particle diameter of the fumed silica is 0.06 μm, the preferable upper limit is 2 μm, the more preferable lower limit is 0.07 μm, and the more preferable upper limit is 1 μm.

In addition, in this specification, the average particle diameter of fumed silica is determined by measuring methyl ethyl ketone, methyl ethyl ketone/toluene (60:40) solution, etc. before mixing, using either a laser scattering/diffraction method or a dynamic light scattering method. It refers to the particle size measured by fumed silica dispersed in the medium.

When mixing the fumed silica, the mixing amount is preferably 40 parts by weight or less based on 100 parts by weight of the curable adhesive component. At a blending amount of 40 parts by weight or less, the effect of improving cohesion and making the adhesive layer uniform and the effect of improving adhesive non-residual property can be exhibited. The lower limit of the amount of the fumed silica to be added is not particularly limited, but it is preferable to mix 3 parts by weight or more in order to sufficiently achieve the effect of improving the uniformity of the adhesive and non-stickiness of the adhesive.

The pressure-sensitive adhesive layer may contain a silicone compound (hereinafter also simply referred to as “silicon compound A”) having a functional group capable of crosslinking with the curable pressure-sensitive adhesive component.

Since the silicone compound has excellent heat resistance, it prevents the adhesive from sticking even when heat is generated during the dicing process, and bleeds out to the interface of the adherend during peeling to facilitate peeling. Since the silicone compound has a functional group that can be cross-linked with the curable adhesive component, it chemically reacts with the curable adhesive component when stimulated and enters the curable adhesive component, preventing contamination by the silicone compound adhering to the adherend.

The silicone skeleton of the silicone compound A is not particularly limited, and may be either a D-form or a DT-form. The silicone compound A preferably has a functional group in the side chain or terminal of the silicone skeleton. Among them, it is more preferable to use a silicone compound that has a D-type silicone skeleton and has a functional group at the terminal that can be crosslinked with the curable adhesive component because it is easy to achieve both high initial adhesion and peelability during peeling.

The functional group of the silicone compound A is selected and used appropriately depending on the component of the curable adhesive. For example, when the curable adhesive component is a curable adhesive whose main component is a polymerizable polymer of the (meth)acrylic acid alkyl ester system having a radically polymerizable unsaturated bond in the molecule, a functional group capable of crosslinking with a (meth)acrylic group is selected. .

The functional group crosslinkable with the (meth)acrylic group is a functional group having an unsaturated double bond, and specific examples include vinyl group, (meth)acrylic group, allyl group, maleimide group, etc.

The functional group equivalent weight of the silicone compound A is not particularly limited, but the preferred lower limit is 1 and the preferred upper limit is 20. If the functional group equivalent weight is less than 1, when the obtained adhesive layer is cured, the silicone compound A may not sufficiently enter the photocurable adhesive component, and the adherend may be contaminated or peelability may not be sufficiently exhibited. If it exceeds, sufficient adhesive force may not be obtained. A more preferable upper limit of the functional group equivalent weight is 10, a more preferable lower limit is 2, and a more preferable upper limit is 6.

The molecular weight of the silicone compound A is not particularly limited, but the preferred lower limit is 300 and the preferred upper limit is 50,000. If the molecular weight is less than 300, the chemical resistance and heat resistance of the adhesive layer may become insufficient, and if it exceeds 50,000, mixing with the curable adhesive component may become difficult. The more preferable lower limit of the molecular weight is 400, the more preferable upper limit is 10000, the more preferable lower limit is 500, and the more preferable upper limit is 5000.

The method of synthesizing the silicone compound A is not particularly limited. For example, a silicone resin having a SiH group and a vinyl compound having a functional group capable of crosslinking with the curable adhesive component are reacted through a hydrosilylation reaction to form a silicone resin. Examples include a method of introducing a functional group capable of crosslinking with the curable adhesive component, or a method of condensing a siloxane compound and a siloxane compound having a functional group crosslinkable with the curable adhesive component.

Among the silicone compounds A, commercially available ones include, for example, X-22-164, X-22-164AS, X-22-164A, X-22-164B, X-22-164C, and -Silicone compounds having a methacryl group at both terminals, such as 22-164E, and silicone compounds having a methacryl group at one terminal, such as X-22-174DX, X-22-2426, and or silicone compounds having an acrylic group such as EBECRYL350 or EBECRYL1360 manufactured by Daicel Scitech, or silicone compounds having an acrylic group such as AC-SQ TA-100 or AC-SQ SI-20 manufactured by Toa Synthetics. Silicone compounds having a methacryl group such as MAC-SQTM-100, MAC-SQSI-20, and MAC-SQHDM can be mentioned.

Among them, the silicone compound A has particularly high chemical resistance and heat resistance, and has high polarity, so it is easy to bleed out from the adhesive layer, so it has the following general formulas (I), general formula (II), and general formula (III) ) A silicone compound having a (meth)acrylic group in the siloxane skeleton is preferred.

[Formula 5]

In the formula, X and Y represent an integer from 0 to 1200 (except for the case where both

Among the silicone compounds having a (meth)acrylic group in the siloxane skeleton represented by the general formula (I), general formula (II), and general formula (III), commercially available ones include, for example, EBECRYL350 manufactured by Daicel Scitech. , EBECRYL1360 (both R is an acrylic group), etc.

In addition, the silicone compound having a three-dimensional structure represented by the following general formula (IV) can also be used.

[Formula 6]

The content of the silicone compound A has a preferable lower limit of 0.5 parts by weight and a preferable upper limit of 50 parts by weight based on 100 parts by weight of the curable adhesive component. If the content of silicone compound A is less than 0.5 parts by weight, the adhesive strength may not be sufficiently reduced even when stimulated, and peeling from the adherend may not be possible. If it exceeds 50 parts by weight, it may cause contamination of the adherend. . The more preferable lower limit of the content of silicone compound A is 1 part by weight, and the more preferable upper limit is 40 parts by weight.

For the purpose of controlling the cohesive force, the adhesive layer may optionally contain various polyfunctional compounds blended with general adhesives such as isocyanate compounds, melamine compounds, and epoxy compounds.

The adhesive layer may contain known additives such as plasticizers, resins, surfactants, waxes, and fine particle fillers.

The adhesive layer has a storage shear modulus of elasticity at 25°C measured under conditions of continuous temperature increase from -50°C to 300°C in the shear mode of dynamic viscoelasticity measurement before the dicing tape attaching process, and is 1.0 × 10 ² to 2.0 × 10 ⁵ Pa. It is desirable to be Since the storage shear modulus of the adhesive layer before crosslinking and curing is within this range, even if the wafer has irregularities of 20 ㎛ or more in height on the surface, it can exhibit high irregularity tracking properties that can follow the irregularities more reliably, and reliably adhere to the wafer. can protect. The more preferable lower limit of the storage shear modulus at 25°C before the dicing tape sticking process of the adhesive layer is 1.0×10 ³ Pa, and the more preferable upper limit is 1.0×10 ⁵ Pa.

The adhesive layer has a storage shear modulus ^{of 2.0} It is desirable. Since the storage shear modulus of the adhesive layer after crosslinking and curing is within this range, positional misalignment does not occur even when an aqueous organic solvent is used in the dicing process, and the wafer is sufficiently protected, and the resulting semiconductor chip There is no case of attachment of residues to the product. In addition, even in the case of a wafer processing process in which a treatment involving heating is performed on a wafer reinforced with a dicing tape after the adhesive layer curing process and before the dicing process, the adhesive layer of the dicing tape shrinks due to heating. It is possible to prevent warping of the wafer or increased adhesion, causing residues to adhere to the surface of the semiconductor chip. The more preferable lower limit of the storage shear modulus of the adhesive layer at 25°C after the adhesive layer curing step is 1.0×10 ⁶ Pa, and the more preferable upper limit is 5.0×10 ⁸ Pa.

The thickness of the adhesive layer is not particularly limited, but the preferred lower limit is 5 μm and the preferred upper limit is 100 μm. If the thickness of the adhesive layer is within this range, it can be adhered to the wafer with sufficient adhesive force and can protect the wafer being processed. A more preferable lower limit of the thickness of the adhesive layer is 10 μm, and a more preferable upper limit is 50 μm.

When the wafer has irregularities on the surface of 20 μm or more in height, it is also effective to make the thickness of the adhesive layer thinner than the height of the irregularities of the wafer.

A passivation film made of a resin such as polyimide may be formed on the surface of the wafer for the purpose of protecting the surface of the wafer. When a dicing tape is attached to the uneven surface of such a wafer, the convex portions may penetrate into the adhesive layer and come into direct contact with the passivation film. If a wafer processing step involving heating is performed in such a state, the adhesive layer is likely to stick to the passivation film and cause adhesive residue. By making the thickness of the adhesive layer thinner than the height of the unevenness of the wafer, the adhesive layer can be prevented from directly contacting the passivation film when sticking, thereby further preventing the occurrence of adhesive residue.

When the thickness of the adhesive layer is thinner than the height of the unevenness of the wafer, the lower limit of the difference between the thickness of the adhesive layer and the height of the unevenness of the wafer is preferably 10 μm and a preferable upper limit of 100 μm. If the difference is less than 10 μm, there may be a portion where the adhesive layer and the passivation film come into direct contact when affixed, causing residual adhesive material. If the difference exceeds 100 μm, the adhesive force becomes insufficient and the wafer may not be sufficiently protected. A more preferable lower limit of the difference is 20 μm, and a more preferable upper limit is 80 μm.

The base film is not particularly limited and includes, for example, a film made of transparent resin such as acrylic, olefin, polycarbonate, vinyl chloride, ABS, polyethylene terephthalate (PET), nylon, urethane, polyimide, etc., and a mesh-like structure. Films with holes, films with holes, etc. can be mentioned.

The thickness of the base film is not particularly limited, but the preferred lower limit is 10 μm and the preferred upper limit is 200 μm. If the thickness of the base film is within this range, the wafer can be sufficiently reinforced and the semiconductor chip can be easily peeled in the semiconductor chip peeling process.

In the semiconductor chip manufacturing method of the present invention, a pressure-sensitive adhesive layer curing step is then performed in which the pressure-sensitive adhesive layer is stimulated to crosslink and harden the curable pressure-sensitive adhesive component. As a result, even when an aqueous organic solvent is used in the dicing process, the wafer can be sufficiently protected without any misalignment, and further, residues do not adhere to the obtained semiconductor chip.

As the curable adhesive component, for example, when a photocurable adhesive component containing a polymer having an unsaturated double bond such as a vinyl group in the side chain and a photopolymerization initiator activated at a wavelength of 250 to 800 nm is used, a wavelength of 365 nm or more is used. By irradiating light, the curable adhesive component can be crosslinked and cured. For such a photocurable adhesive component, for example, it is preferable to irradiate light with a wavelength of 365 nm at an illuminance of 5 mW or more, more preferably irradiate with an illuminance of 10 mW or more, and irradiate with an illuminance of 20 mW or more. It is more preferable, and irradiation at an illuminance of 50 mW or more is particularly preferable. In addition, it is preferable to irradiate light with a wavelength of 365 nm at an integrated illuminance of 300 mJ or more, more preferably irradiate with an integrated illuminance of 500 mJ or more and 10,000 mJ or less, and irradiate with an integrated illuminance of 500 mJ or more and 7,500 mJ or less. It is more preferable to irradiate at an integrated illuminance of 1000 mJ or more and 5000 mJ or less.

In the semiconductor chip manufacturing method of the present invention, after the adhesive layer curing step and before the next step, the dicing step, there may be a wafer processing step in which a wafer reinforced with a dicing tape is subjected to a treatment involving heating. In the semiconductor chip manufacturing method of the present invention, even when such a wafer processing step is performed, the curable adhesive component is crosslinked and cured in the adhesive layer curing step before the wafer processing step, thereby preventing the occurrence of warping due to heat or the semiconductor chip. It is possible to prevent residues from adhering to the surface.

The wafer processing process that performs the treatment involving heating includes, for example, grinding treatment in which the wafer is ground to a certain thickness, sputtering, deposition, etching, chemical vapor deposition (CVD), and physical vapor deposition method. (PVD), resist application/patterning, reflow, etc.

In the method for manufacturing a semiconductor chip of the present invention, a dicing process is performed to obtain a semiconductor chip by dicing the wafer reinforced with a dicing tape.

The method of the dicing is not particularly limited, and a conventionally known method of cutting and separating using a grindstone or the like can be used.

During dicing, an aqueous organic solvent such as an aqueous isopropyl alcohol solution may be sprayed on the surface of the wafer to remove cutting debris. The adhesive layer crosslinked and cured in the adhesive curing step can exhibit sufficient chemical resistance even to aqueous organic solvents.

In the method for manufacturing a semiconductor chip of the present invention, a semiconductor chip peeling step of peeling the semiconductor chip from the dicing tape is then performed.

The method of peeling the semiconductor chip is not particularly limited, and conventionally known methods can be used. That is, either a needle pickup method in which the obtained semiconductor chip is pushed up with a needle from the dicing tape side may be used, or a needleless pickup method that does not use a needle may be used.

In the adhesive curing process, the crosslinked and cured adhesive layer has an increased elastic modulus, so the semiconductor chip can be easily peeled off without residue adhering. Moreover, even if time passes after attaching the dicing tape to the wafer, there is almost no case where adhesion increases.

When the pressure-sensitive adhesive layer contains the gas generator, the semiconductor chip can be peeled off more easily by generating a stimulus in the semiconductor chip peeling process to generate gas from the gas generator.

For example, when a gas generating agent that generates gas is used as the gas generating agent by irradiating light with a wavelength of 300 nm or less, gas is generated from the gas generating agent by irradiating light with a wavelength of 300 nm or less. This allows the semiconductor chip to be more easily peeled from the dicing tape.

For such a gas generating agent, for example, it is preferable to irradiate light with a wavelength of 254 nm at an illuminance of 5 mW or more, more preferably irradiate with an illuminance of 10 mW or more, and even more preferably irradiate with an illuminance of 20 mW or more. It is preferable, and irradiation at an illuminance of 50 mW or more is particularly preferable. In addition, it is preferable to irradiate light with a wavelength of 254 nm at an integrated illuminance of 1000 mJ or more, more preferably irradiate at an integrated illuminance of 1000 mJ or more and 20 J or less, and irradiate with an integrated illuminance of 1500 mJ or more and 15 J or less. It is more preferable to irradiate at an integrated illuminance of 2000 mJ or more and 10 J or less.

According to the present invention, as a method of manufacturing a semiconductor chip by dicing a wafer in a state reinforced with a dicing tape, no misalignment occurs even when an aqueous organic solvent is used, and further, the obtained semiconductor chip It is possible to provide a method for manufacturing a semiconductor chip that does not cause residues to adhere to the semiconductor chip.

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

(Example 1)

(1) Preparation of dicing tape

A reactor equipped with a thermometer, a stirrer, and a cooling pipe was prepared, and in this reactor, 94 parts by weight of 2-ethylhexyl acrylate as an alkyl (meth)acrylate ester, 6 parts by weight of hydroxyethyl methacrylate as a functional group-containing monomer, After adding 0.01 parts by weight of lauryl mercaptan and 80 parts by weight of ethyl acetate, the reactor was heated to initiate reflux. Subsequently, 0.01 part by weight of 1,1-bis(t-hexylperoxy)-3,3,5-trimethylcyclohexane was added into the reactor as a polymerization initiator, and polymerization was initiated under reflux. Next, 1 hour and 2 hours after the start of polymerization, 0.01 parts by weight of 1,1-bis(t-hexylperoxy)-3,3,5-trimethylcyclohexane was added, and further 4 hours after the start of polymerization. After some time, 0.05 parts by weight of t-hexylperoxypivalate was added to continue the polymerization reaction. Then, 8 hours after the start of polymerization, an ethyl acetate solution of a functional group-containing (meth)acrylic polymer with a solid content of 55% by weight and a weight average molecular weight of 600,000 was obtained.

With respect to 100 parts by weight of the resin solid content of the ethyl acetate solution containing the obtained functional group-containing (meth)acrylic polymer, 3.5 parts by weight of 2-isocyanato ethyl methacrylate as a functional group-containing unsaturated compound was added and reacted to obtain a photocurable adhesive.

Based on 100 parts by weight of the resin solid content of the ethyl acetate solution of the obtained photocurable adhesive, 1 part by weight of a photopolymerization initiator (Esacurewan, manufactured by Nippon Siebel Hegna Co., Ltd.) and a silicone compound having a (meth)acrylic group (Daicel Cytech Co., Ltd.) An adhesive was prepared by mixing 2 parts by weight of EBECRYL350 (acrylic equivalent 2)), 10 parts by weight of a plasticizer (UN-5500, manufactured by Negami Kogyo Co., Ltd.), and 0.5 parts by weight of a crosslinker (Colonate L-45, manufactured by Nippon Polyurethane Co., Ltd.). An ethyl acetate solution of the composition was prepared.

The ethyl acetate solution of the obtained adhesive composition was applied with a doctor knife on the corona-treated side of a 50-μm-thick transparent polyethylene naphthalate film that had been corona-treated on one side so that the dry film had a thickness of 30 μm, and heated at 110°C for 5 days. The coating solution was dried by heating for a minute. After that, static curing was performed at 40°C for 3 days to obtain a dicing tape.

(2) Evaluation of elastic modulus of the adhesive layer before and after ultraviolet irradiation

As a sample for evaluation, an ethyl acetate solution of a photocurable adhesive was applied on the corona-treated side of a 50-μm-thick transparent polyethylene naphthalate film corona-treated on one side with a doctor knife so that the dry film thickness was 500 μm. , the coating solution was dried by heating at 110°C for 5 minutes, and then cured at 40°C for 3 days. The obtained adhesive tape was cut into a rectangular shape of 0.6 cm in length and 1.0 cm in width, and this was used as a sample for evaluation.

Next, using an ultra-high pressure mercury lamp, ultraviolet rays of 365 nm were irradiated to the tape surface for 2 minutes with the illuminance adjusted so that the irradiation intensity was 80 mW/cm2, and the photocurable adhesive component was crosslinked and cured. For the evaluation samples before and after curing, measurements were made at an angular frequency of 10 Hz in the shear mode of dynamic viscoelasticity measurement, and the value of the storage elastic modulus at 25°C was obtained among the measured values in which the temperature was continuously raised from -50°C to 300°C.

As a result, the storage shear modulus at 25°C before irradiation with ultraviolet rays was 1.1 × 10 ⁴ Pa, and the storage shear modulus at 25°C after irradiation with ultraviolet rays was 2.3 × 10 ⁷ Pa.

(2) Manufacturing of semiconductor chips

The side of the dicing tape on the adhesive layer side was affixed to the surface of a silicon wafer with a diameter of 20 cm and a thickness of approximately 100 μm to obtain a laminate. Next, using an ultra-high pressure mercury lamp, ultraviolet rays of 365 nm were irradiated for 1 minute with the illuminance adjusted so that the irradiation intensity on the surface of the dicing tape was 80 mW/cm2, and the photocurable adhesive component was crosslinked and cured.

The wafer reinforced with the dicing tape was diced by cutting and separating it using a grindstone or the like to obtain a 10 mm x 10 mm semiconductor chip. During dicing, an aqueous isopropyl alcohol solution was sprayed on the surface of the wafer to remove cutting debris. During the dicing process, the wafer was sufficiently fixed to the dicing tape, and no misalignment was observed at all.

After the dicing process, the obtained semiconductor chip was peeled off by pushing it up from the dicing tape side with a needle.

The surfaces of all the obtained semiconductor chips were observed at a magnification of 100 times using an optical microscope, but no residue was found to adhere to any of the semiconductor chips.

(Example 2)

As a silicon wafer, a silicon wafer with a diameter of 20 cm and a thickness of approximately 100 μm on which a circuit having a groove with a height of 20 μm and a width of 100 μm is formed on one surface is used, and a dicing tape is attached to the circuit surface to form a laminate. A semiconductor chip was manufactured in the same manner as in Example 1 except for the results obtained.

As a result, during the dicing process, the wafer was sufficiently fixed to the dicing tape, no misalignment was confirmed, and the surfaces of all obtained semiconductor chips were observed at a magnification of 100 times using an optical microscope. , there were no semiconductor chips at all on which residues were confirmed to have attached.

(Example 3)

As a silicon wafer, a silicon wafer with a diameter of 20 cm and a thickness of approximately 100 μm, on which an electrode with a height of 80 μm was formed on the surface of which a passivation film made of polyimide was formed, was used, and a dicing tape was attached to the electrode surface to obtain a laminate. Other than that, a semiconductor chip was manufactured in the same manner as in Example 1.

As a result, during the dicing process, the wafer was sufficiently fixed to the dicing tape, no misalignment was confirmed, and the surfaces of all obtained semiconductor chips were observed at a magnification of 100 times using an optical microscope. , there were no semiconductor chips at all on which residues were confirmed to have attached.

(Example 4)

In the manufacture of semiconductor chips, after crosslinking and curing the photocurable adhesive component and before dicing, the wafer reinforced with dicing tape is placed in a reflow furnace and heat treated at 260°C for 6 minutes. A semiconductor chip was manufactured in the same manner as in Example 1, except that it was carried out a total of three times.

As a result, during the dicing process, the wafer was sufficiently fixed to the dicing tape, no misalignment was confirmed, and the surfaces of all obtained semiconductor chips were observed at a magnification of 100 times using an optical microscope. , there were no semiconductor chips at all on which residues were confirmed to have attached.

(Comparative Example 1)

A semiconductor chip was manufactured in the same manner as in Example 1, except that before the dicing process, ultraviolet irradiation was not performed and the photocurable adhesive component was not crosslinked or cured.

As a result, during the dicing process, the adhesive force of the dicing tape decreased and slight misalignment occurred. Additionally, the surfaces of all the obtained semiconductor chips were observed at a magnification of 100 times using an optical microscope, and as a result, semiconductor chips with residue attached were confirmed.

(Comparative Example 2)

Before sticking to the wafer, a semiconductor chip was manufactured in the same manner as in Example 2, except that the dicing tape was irradiated with ultraviolet rays to crosslink and cure the photocurable adhesive component.

However, the dicing tape did not adhere sufficiently to the wafer, so the dicing process could not be performed.

(Comparative Example 3)

As a silicon wafer, a silicon wafer with a diameter of 20 cm and a thickness of about 100 μm, on which a passivation film made of polyimide is formed, an electrode with a height of 20 μm is formed, a dicing tape is attached to the electrode surface to obtain a laminate, A semiconductor chip was manufactured in the same manner as in Example 3, except that before the dicing process, ultraviolet irradiation was not performed and the photocurable adhesive component was not crosslinked or cured.

As a result, during the dicing process, the adhesive force of the dicing tape decreased and slight misalignment occurred. Additionally, as a result of observing the surfaces of all the obtained semiconductor chips at a magnification of 100 times using an optical microscope, many semiconductor chips with residues attached were confirmed.

(Comparative Example 4)

A semiconductor chip was manufactured in the same manner as in Example 4, except that before the dicing process, ultraviolet irradiation was not performed and the photocurable adhesive component was not crosslinked or cured.

As a result, during the dicing process, the adhesive force of the dicing tape decreased and slight misalignment occurred. Additionally, as a result of observing the surfaces of all the obtained semiconductor chips at a magnification of 100 times using an optical microscope, many semiconductor chips with residues attached were confirmed.

According to the present invention, as a method of manufacturing a semiconductor chip by dicing a wafer in a state reinforced with a dicing tape, no misalignment occurs even when an aqueous organic solvent is used, and further, the obtained semiconductor chip It is possible to provide a method for manufacturing a semiconductor chip that does not cause residues to adhere to the semiconductor chip.

Claims (7)

A dicing tape attaching step of attaching a dicing tape composed of a base film and an adhesive layer containing at least a curable adhesive component that crosslinks and hardens by stimulation to the wafer from the adhesive layer side for reinforcement;
A pressure-sensitive adhesive layer curing step of stimulating the pressure-sensitive adhesive layer to crosslink and harden the curable pressure-sensitive adhesive component;
A dicing process to obtain a semiconductor chip by dicing the wafer reinforced with the dicing tape;
A method of manufacturing a semiconductor chip, comprising a semiconductor chip peeling process for peeling the semiconductor chip from the dicing tape. According to claim 1,
A method of manufacturing a semiconductor chip, characterized in that the wafer has irregularities of 20 μm or more in height on the surface of the side to which the single-sided adhesive tape is attached. According to claim 2,
A method of manufacturing a semiconductor chip, characterized in that the thickness of the adhesive layer of the dicing tape is thinner than the height of the unevenness of the wafer. According to any one of claims 1, 2 or 3,
The storage shear modulus at 25°C measured under conditions of continuous temperature increase from -50°C to 300°C in the shear mode of dynamic viscoelasticity measurement for the adhesive layer before the dicing tape attachment process is 1.0 × 10 ² to 2.0 × 10 ⁵ Pa, and the storage shear modulus at 25°C, measured under conditions of continuous temperature increase from -50°C to 300°C in the shear mode of dynamic viscoelasticity measurement for the pressure-sensitive adhesive layer after the pressure-sensitive adhesive layer curing process, is 2.0 × 10 ⁵ ∼ A method of manufacturing a semiconductor chip, characterized in that 1.0 × 10 ⁹ Pa. According to any one of claims 1, 2, 3 or 4,
A semiconductor chip manufacturing method comprising a wafer processing step in which a wafer reinforced with a dicing tape is treated with heating after the adhesive layer curing step and before the dicing step. According to any one of claims 1, 2, 3, 4 or 5,
A method of manufacturing a semiconductor chip, wherein the stimulus for crosslinking and curing the curable adhesive component is ultraviolet rays. According to any one of claims 1, 2, 3, 4, 5 or 6,
The adhesive layer further contains a gas generating agent that generates gas by stimulation, and gas is generated from the gas generating agent by applying stimulation in the semiconductor chip peeling process. A method of manufacturing a semiconductor chip.