JP6533150B2 - Protective agent for semiconductor laser dicing and method of manufacturing semiconductor using the same - Google Patents

Description

  The present invention relates to a protective agent for semiconductor laser dicing, which forms a protective film for semiconductor laser dicing, and a method of manufacturing a semiconductor using the same.

  A semiconductor wafer used in the manufacture of a semiconductor device is a laminate in which an insulating film and a functional film are laminated on the surface of a semiconductor substrate such as silicon. A semiconductor chip (for example, an IC, an LSI chip or the like) is manufactured by irradiating a semiconductor wafer with a laser beam to produce a groove and then performing cutting along the groove.

  However, when the semiconductor wafer is irradiated with laser light, the laser light is absorbed by the semiconductor substrate such as silicon, so that a melt or thermal decomposition product of the semiconductor substrate is generated, and the melt or thermal decomposition product is attached There is a problem that it adheres to the surface of a semiconductor wafer or a semiconductor chip as debris.

In order to solve the problem caused by such debris, in Patent Documents 1 and 2, a protective film is formed on the wafer surface using a water-soluble resin, and laser irradiation (laser dicing) is performed via the protective film. By carrying out, the method of making a debris adhere on the surface of a protective film, and removing a debris with a protective film by water washing is proposed.
However, in the methods of Patent Documents 1 and 2, when the laser beam is irradiated, the thermal decomposition of the semiconductor substrate proceeds prior to the thermal decomposition of the protective film, and the protective film and the semiconductor chip are generated by the pressure of silicon vapor which is the thermal decomposition product. Since an air gap is formed at the cut portion of the surface by the laser beam and debris adheres to the cut portion of the surface of the semiconductor chip by the laser beam, adhesion of the debris to the semiconductor chip can not be sufficiently prevented. As a method for solving such a problem, Patent Document 3 discloses at least one water-soluble laser absorber selected from the group consisting of a water-soluble resin, a water-soluble dye, a water-soluble dye, and a water-soluble UV absorber. A technique has been described in which a protective film for laser dicing is formed using a solution in which it is dissolved (hereinafter sometimes referred to simply as a laser absorber).

On the other hand, since a semiconductor chip which does not contain metal impurities as much as possible is required as a semiconductor chip, it is necessary to apply the solution on the semiconductor wafer after removing the metal impurities as much as possible. Be done. However, in the method described in Patent Document 3, there is a problem that metal impurities are mixed or the laser absorber itself is removed by the ion exchange treatment because the laser absorber is used.
Further, in the method described in Patent Document 3, there is also a problem that when the ultraviolet absorber is used, the cost is increased because the ultraviolet absorber is expensive.

Sho 53-8634 Unexamined-Japanese-Patent No. 5-211381 Patent No. 4571850

An object of the present invention is to provide a novel protective agent for forming a protective film for semiconductor laser dicing.
Another object of the present invention is to provide a method of manufacturing a semiconductor using the protective agent.

  As a result of intensive studies to solve the above problems, the present inventors apply a polyvinyl alcohol resin having an ultraviolet absorbing group (hereinafter sometimes referred to as a PVA resin) to the surface of a semiconductor wafer for protection. If laser dicing is performed after the film is formed, adhesion of debris to the semiconductor surface can be efficiently prevented without using a laser absorber other than the polyvinyl alcohol resin having the ultraviolet absorbing group, and laser dicing It has been found that the subsequent washing with water can remove the protective film and the debris generated by laser dicing from the semiconductor wafer. The inventors further researched and completed the present invention.

That is, the present invention relates to the following protective agent for semiconductor laser dicing and the like.
[1] A protective agent for semiconductor laser dicing comprising a polyvinyl alcohol resin (A) having an ultraviolet absorbing group.
[2] The protective agent for semiconductor laser dicing according to the above [1], wherein the ultraviolet ray absorbing group is a group derived from a carbonyl compound having an ultraviolet ray absorbing group.
[3] The protective agent for semiconductor laser dicing according to the above [2], wherein the carbonyl compound is an aldehyde.
[4] The protective agent for semiconductor laser dicing according to the above [3], wherein the aldehyde is an aldehyde having two or more carbon-carbon double bonds.
[5] The aldehyde consists of 4-hydroxybenzaldehyde, 2,4-dihydroxybenzaldehyde, 3,4-dihydroxybenzaldehyde, vanillin, 4-nitrobenzaldehyde, 1-naphthaldehyde, 2-hydroxy-1-naphthaldehyde and cinnamaldehyde The protective agent for semiconductor laser dicing according to the above [3] or [4], which is at least one selected from the group consisting of
[6] The protective agent for semiconductor laser dicing according to any one of the above [1] to [5], wherein the degree of saponification of the polyvinyl alcohol resin (A) is 60 mol% or more.
[7] The protective agent for semiconductor laser dicing according to any one of the above [1] to [6], wherein the average degree of polymerization of the polyvinyl alcohol resin (A) is 100 to 4000.
[8] The protective agent for semiconductor laser dicing according to any one of the above [1] to [7], wherein the modification degree of the polyvinyl alcohol resin (A) is 0.1 to 10 mol%.
[9] A composition comprising the protective agent for semiconductor laser dicing according to any one of the above [1] to [8].
[10] The composition according to the above [9], further comprising a polyvinyl alcohol resin (B) different from the polyvinyl alcohol resin (A).
[11] The composition according to [10], wherein the degree of saponification of the polyvinyl alcohol resin (B) is within ± 3 mol% of the degree of saponification of the polyvinyl alcohol resin (A).
[12] The composition according to the above [10] or [11], wherein the average degree of polymerization of the polyvinyl alcohol resin (B) differs from that of the polyvinyl alcohol resin (A) by 100 or more.
[13] The composition according to any one of the above [9] to [12], further containing water.
[14] The composition according to any one of the above [9] to [13], further containing an organic solvent.
[15] The composition according to any one of the above [9] to [14], wherein the content of metal impurities is 50 ppb or less.
[16] The composition according to any one of [13] to [15], wherein the maximum particle size of the insoluble component in the solution is 3 μm or less.
[17] A method for producing a semiconductor, comprising the step of deionizing the composition according to any one of [9] to [16] by ion exchange treatment.
[18] A method for producing a semiconductor, comprising the step of filtering the composition according to any one of the above [9] to [16] with a filter having a pore size of 1 μm or less.

According to the present invention, a novel protective agent for forming a protective film for semiconductor laser dicing can be provided.
Further, according to the present invention, it is possible to provide a method of manufacturing a semiconductor using the protective agent.
Furthermore, by applying the protective agent of the present invention to the surface of a semiconductor wafer to form a protective film and then performing laser dicing, adhesion of debris to the semiconductor surface can be efficiently prevented even without using a laser absorber. The debris generated by laser dicing can be easily removed by water washing together with the protective film. Thus, since the protective agent of the present invention does not need to use a laser absorber, it can prevent the mixing of metal impurities, and even when metal impurities are contained, metal impurities are removed by performing ion exchange treatment. It is also possible to solve the problem that the laser absorber itself is removed by ion exchange treatment.
Further, according to the present invention, since the protective film absorbs and decomposes the laser light prior to the thermal decomposition of the semiconductor substrate by the laser light, generation of a thermal decomposition product of the semiconductor substrate causes the laser on the surface of the protective film and the semiconductor chip. No void is formed in the light-cut portion. As described above, according to the present invention, since the adhesion between the protective film and the semiconductor chip is excellent even when the laser light is irradiated, debris does not adhere to the cut portion of the surface of the semiconductor chip by the laser light. Further, according to the present invention, such adhesion between the protective film and the semiconductor chip can be obtained without containing a laser absorber.

Hereinafter, modes for carrying out the present invention will be described in detail. The present invention is not limited to the embodiments described below.
The protective agent for semiconductor laser dicing of the present invention is usually composed of a PVA-based resin (A) having an ultraviolet absorbing group.

[PVA-based resin (A)]
The PVA-based resin (A) is not particularly limited as long as it has an ultraviolet absorbing group. In the PVA-based resin (A), the position of the ultraviolet absorbing group is not particularly limited, and may be a main chain, a side chain or the like, but it is preferable to have an ultraviolet absorbing group at least in the side chain.
The ultraviolet ray absorbing group is not particularly limited, but for example, a group which can be introduced through the OH group of the PVA resin and a group derived from a carbonyl compound having an ultraviolet ray absorbing group is preferable.

Representative carbonyl compounds include carbonyl compounds having a carbon-carbon double bond. As the carbonyl compound, aldehydes, ketones and the like are preferable.
In the carbonyl compound, the number of carbon-carbon double bonds is not particularly limited as long as it has ultraviolet absorptivity, but, for example, 2 or more (for example, 2 to 10), preferably 2 to 8 (for example, 2 to 2) 6), more preferably about 2 to 4 (e.g. 2 to 3).

In the carbonyl compound, the position of the carbon-carbon double bond is not particularly limited as long as it has ultraviolet absorptivity, but generally, at least α, β positions (that is, carbonyl carbon is 1 position) to the carbonyl group of the carbonyl compound. Sometimes it is preferable to have 2).
When the carbonyl compound has a plurality of carbon-carbon double bonds, the positional relationship of the double bonds is not particularly limited, but in particular, the plurality of carbon-carbon double bonds form a conjugated system (in particular, Preferably, they form a conjugated system with the carbonyl group. The carbonyl compound may form a conjugated system with the aromatic ring.
For example, a carbonyl compound having two carbon-carbon double bonds is carbon-carbon 2 at the α, β and γ, δ positions (that is, position 4 when the carbonyl carbon is at position 1) with respect to the carbonyl group. It may have a double bond.
Specific examples of the carbonyl compound include aldehydes having two or more carbon-carbon double bonds, and ketones having two or more carbon-carbon double bonds.

The aldehyde is not particularly limited, and examples thereof include aldehydes having two or more carbon-carbon double bonds, preferably aromatic aldehydes (eg, benzaldehyde compounds, naphthaldehyde compounds, etc.), unsaturated fatty acids Family aldehydes (eg, alkadienals (eg, 2,4-alkadienals having 5 to 20 carbon atoms, etc.), alkatrienals (eg, Nal and the like) and the like. The aldehyde may have a substituent (eg, a hydroxyl group, a nitro group, etc.). One or more of these aldehydes can be used.
Among the aromatic aldehydes, particularly preferably benzaldehyde compounds {eg, benzaldehyde, benzaldehyde compounds having a hydroxyl group (eg, 4-hydroxybenzaldehyde, 2,4-dihydroxybenzaldehyde, 3,4-dihydroxybenzaldehyde, vanillin etc.), Benzaldehyde compounds (eg, 4-nitrobenzaldehyde) having a nitro group}, naphthaldehyde compounds {eg, 1-naphthaldehyde, naphthaldehyde compounds having a hydroxyl group (eg, 2-hydroxy-1-naphthaldehyde, etc.) And so on}, cinnamaldehyde and the like.

  The PVA-based resin (A) has, for example, a unit represented by the following formula (1) as a unit having an ultraviolet absorbing group.

（式中、Ｒ^１は炭素―炭素２重結合を２つ以上有する基を示し、Ｒ^２は水素原子又は置換基を示す。）

(Wherein, R ¹ represents a group having two or more carbon-carbon double bonds, and R ² represents a hydrogen atom or a substituent.)

In R ¹ , examples of the group having two or more (for example, 2 to 10, etc.) carbon-carbon double bonds include, for example, unsaturated aliphatic groups {alkadienyl groups (for example, 1 to 3 carbon atoms of 1, 3 and 2) -Alkadienyl group etc.), Alkatrienyl group (eg, C6-20 carbon atom 1,3,6-alkatrienyl group etc.)}, aromatic group (eg carbon hydrocarbon 6 to 20 aromatic hydrocarbon group) Etc.). These groups may be further substituted by one or more substituents (for example, halogen atoms, hydroxyl groups, carboxyl groups, ether groups, ester groups, alkoxy groups, nitro groups, amino groups, etc.).
As R ¹ , preferably, a phenyl group, a phenyl group having a hydroxyl group (eg, 4-hydroxyphenyl group, 2,4-dihydroxyphenyl group, 3,4-dihydroxy group, 3-methoxy-4-hydroxyphenyl group, etc.) And a phenyl group having a nitro group, such as 4-nitrophenyl group, a naphthyl group, a naphthyl group having a hydroxyl group such as a 2-hydroxynaphthyl group, and the like.
R ¹ often corresponds to a UV absorbing group derived from a carbonyl compound.

In R ² , examples of the substituent include organic residues such as a hydrocarbon group, and the like.
As a hydrocarbon group, for example, an aliphatic group (for example, a saturated aliphatic group (for example, an alkyl group having 1 to 20 carbon atoms and the like), an unsaturated aliphatic group (for example, an alkenyl group having 2 to 20 carbon atoms and the like) }, An aromatic group (for example, an aromatic hydrocarbon group having 6 to 20 carbon atoms, etc.) and the like. The hydrocarbon group may be further substituted by one or more substituents (for example, a halogen atom, a hydroxyl group, a carboxyl group, an ether group, an ester group, an alkoxy group, a nitro group, an amino group, etc.).

The average degree of polymerization of the PVA-based resin (A) is not particularly limited, but is preferably 100 to 4000, more preferably 200 to 2000, and still more preferably 300, from the viewpoint of being able to adjust to a viscosity suitable for spin coating or the like. 1000. In the present invention, the average degree of polymerization of the PVA-based resin can be determined by the method of measuring the average degree of polymerization of PVA specified in JIS K 6726.
Moreover, as PVA-type resin (A), you may use 2 or more types of different PVA-type resin (A) which belongs to the category of PVA-type resin (A), PVA-type resin (A1) and PVA-type resin ( When A2) is included, the average polymerization degree of the PVA-based resin (A1) and the average polymerization degree of the PVA-based resin (A2) may be the same or different. In particular, from the viewpoint of facilitating adjustment to a viscosity suitable for spin coating on a semiconductor, the average degree of polymerization of the PVA resin (A1) is an average degree of polymerization of the PVA resin (A2) of 100 or more (for example, 100) 1000) preferably different. For example, a PVA-based resin (A1) having a low average polymerization degree (for example, an average polymerization degree of 100 to 500) [for example, a PVA-based resin having a unit of the above formula (1) wherein R ¹ is a 1,3-alkadienyl group When using (A1), a PVA-based resin (A1) or the like having a unit of the above formula (1) in which R ¹ is a 1,3,6-alkatrienyl group, the average polymerization of the PVA-based resin (A2) The degree is preferably 100 or more (e.g., 100 to 1000) larger than the average degree of polymerization of the PVA-based resin (A1).

The degree of saponification of the PVA-based resin (A) is not particularly limited, but is preferably 60 mol% or more (for example, 60 to 100 mol%), more preferably from the viewpoint of easy removal of the protective film by washing with water. It is 65 to 95 mol%, more preferably 70 to 90 mol%. In the present invention, the degree of saponification of the PVA-based resin can be determined by the method of measuring the degree of saponification of PVA specified in JIS K 6726.
Moreover, when PVA-type resin (A) contains PVA-type resin (A1) and PVA-type resin (A2), the saponification degree of PVA-type resin (A1) is the saponification degree of PVA-type resin (A2), It may be the same or different, but from the viewpoint of compatibility between the PVA-based resin (A1) and the PVA-based resin (A2), it is better that the difference in saponification degree between the two is as small as possible Preferably, the saponification degree of the PVA resin (A1) is within ± 3 mol% (eg, within ± 0.1 to 3 mol%) of the saponification degree of the PVA resin (A2).

The degree of modification (content of the unit having an ultraviolet absorbing group) of the PVA-based resin (A) is not particularly limited, and is appropriately adjusted depending on the introduced ultraviolet absorbing group, but maintaining water solubility, laser light From the viewpoint of adjusting the absorption characteristics, etc., it is preferably 0.1 to 10 mol%, more preferably 0.5 to 8 mol%, in terms of the monomer of the PVA-based resin (A). In the present invention, the modification degree of the PVA-based resin (A) is, for example, the content ratio of the unit represented by the above formula (1) in the PVA-based resin (A).
When the PVA-based resin (A) contains the PVA-based resin (A1) and the PVA-based resin (A2), the modification degree of the PVA-based resin (A1) is the same as the modification degree of the PVA-based resin (A2) It may be present or different.

[Method of producing PVA-based resin (A)]
Although the manufacturing method of PVA-type resin (A) is not specifically limited, For example, two adjacent OH groups in a vinyl-ester type polymer are acetalized with an aldehyde and / or a ketone, and it displays in a table by Formula (1). It is possible to obtain a PVA-based resin (A) having units to be incorporated.

The vinyl ester polymer to be acetalized is not particularly limited. For example, conventionally known polymers obtained by polymerizing a vinyl ester monomer and then performing a saponification reaction can be used. The polymerization method and the saponification reaction method are not particularly limited, and may be according to conventionally known methods.
The vinyl ester monomer is not particularly limited, and examples thereof include fatty acid vinyl esters such as vinyl acetate, vinyl formate, vinyl propionate, vinyl caprylate (vinyl octanoate), vinyl versatate, and the like. 1 type or 2 types or more can be used. Among these, vinyl acetate is preferable from an industrial viewpoint.

The vinyl ester polymer may be one obtained by copolymerizing a monomer other than the vinyl ester monomer as long as the effects of the present invention are exhibited.
The other monomer is not particularly limited, and examples thereof include α-olefins (eg, ethylene, propylene, n-butene, isobutylene etc.), (meth) acrylic acid and salts thereof, (meth) acrylic esters [ For example, (meth) acrylic acid alkyl ester (for example, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, i-propyl acrylate (meth) acrylate, n (meth) acrylate) -Butyl, i-butyl (meth) acrylate, t-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, dodecyl (meth) acrylate, octadecyl (meth) acrylate, etc. (meth) acrylate C _1-20 alkyl, etc.)], (meth) acrylamide, (meth) acrylamide derivatives [for example, N- methyl (meth) Crylamide, N-ethyl (meth) acrylamide, N, N- dimethyl (meth) acrylamide, diacetone (meth) acrylamide, (meth) acrylamidopropane sulfonic acid and its salt, (meth) acrylamido propyl dimethylamine and its salt or its 4 Salts, N-methylol (meth) acrylamide, etc.], vinyl ethers (eg methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, i-propyl vinyl ether, n-butyl vinyl ether, i-butyl vinyl ether, t-butyl vinyl ether, dodecyl) vinyl ethers, C _1-20 alkyl vinyl ethers such as stearyl vinyl ether), nitriles (e.g., acrylonitrile, methacrylonitrile, etc.), vinyl halides (e.g. For example, vinyl chloride, vinyl fluoride etc., vinylidene halides (eg, vinylidene chloride, vinylidene fluoride etc.), allyl compounds (eg, allyl acetate, allyl chloride etc.), unsaturated dicarboxylic acids (eg, maleic acid, Itaconic acid, fumaric acid and the like) and salts thereof or esters thereof, vinylsilyl compounds (for example, vinyltrimethoxysilane and the like), fatty acid alkyl esters (for example, isopropenyl acetate and the like) and the like. These other monomers can be used alone or in combination of two or more.

  When the other monomer is contained, the amount of the other monomer used is not particularly limited, but is, for example, 0.1 to 20 parts by mass with respect to 100 parts by mass of the vinyl ester monomer.

  Although the usage-amount of an aldehyde is not specifically limited in acetalization, For example, it is 0.1-10 mass parts with respect to 100 mass parts of vinyl ester polymer, Preferably it is 1-8 mass parts.

The acetalization reaction can be carried out, for example, by dissolving or dispersing a vinyl ester polymer and an aldehyde and / or a ketone in a solvent and stirring. After the reaction, a basic compound is preferably added to terminate the reaction.
The solvent is not particularly limited, and examples thereof include water, alcohols such as methanol, ethanol and propanol, ketones such as acetone, and esters such as methyl acetate and ethyl acetate. These can be used singly or in combination of two or more.
The amount of the solvent used is not particularly limited, but is, for example, 100 to 900 parts by mass with respect to 100 parts by mass of the vinyl ester polymer.

The acetalization reaction is preferably carried out in the presence of an acid catalyst. The acid catalyst is not particularly limited, and examples thereof include inorganic acids such as hydrochloric acid, sulfuric acid, nitric acid and phosphoric acid; and organic acids such as formic acid, acetic acid, oxalic acid and p-toluenesulfonic acid.
The use amount of the acid catalyst is not particularly limited, but is, for example, 0.1 to 100 parts by mass with respect to 100 parts by mass of the vinyl ester polymer.

The reaction temperature is not particularly limited, and may be normal temperature or 40 to 80 ° C.
The reaction time is not particularly limited, and is, for example, 1 to 10 hours.
The basic compound to be added at the end of the reaction is not particularly limited, and examples thereof include alkali metal hydroxides such as sodium hydroxide and potassium hydroxide; alkali metal carbonates such as sodium carbonate and potassium carbonate; Examples thereof include quaternary ammonium salts such as oxides.

[Composition]
The protective agent for semiconductor laser dicing of the present invention may be used as it is or may be used as a composition containing the protective agent. That is, the present invention also contains a composition containing the protective agent for semiconductor laser dicing of the present invention.
The composition of the present invention is one or two or more PVA-based resins (B) which do not belong to the category of PVA-based resins (A), from the viewpoint of facilitating adjustment to a viscosity suitable for spin coating on semiconductors. It may further be included.

[PVA-based resin (B)]
The average degree of polymerization of the PVA-based resin (B) is not particularly limited, but is preferably 100 to 4000, more preferably 200 to 2000, and still more preferably 300, from the viewpoint of being able to adjust the viscosity to a spin coat method. 1000.
In particular, the average degree of polymerization of the PVA-based resin (B) differs from that of the PVA-based resin (A) by 100 or more (for example, 100 to 1000) from the viewpoint of easy adjustment to a viscosity suitable for spin coating on a semiconductor. Is preferred. For example, a PVA-based resin (A) having a low average polymerization degree (for example, an average polymerization degree of 100 to 500) [for example, a PVA-based resin having a unit of the above formula (1) in which R ¹ is a 1,3-alkadienyl group (A), when using a PVA-based resin (A) having a unit of the above formula (1) and the like in which R ¹ is a 1,3,6-alkatrienyl group], the average polymerization of the PVA-based resin (B) The degree is preferably 100 or more (e.g., 100 to 1000) larger than the average degree of polymerization of the PVA-based resin (A).

The degree of saponification of the PVA-based resin (B) is not particularly limited, but is preferably 60 mol% or more (for example, 60 to 100 mol%), more preferably from the viewpoint of easy removal of the protective film by washing with water. It is 65 to 95 mol%, more preferably 70 to 90 mol%.
In particular, the saponification degree of the PVA-based resin (B) is within ± 3 mol% (eg, within ± 0.1 to 3 mol%) of the saponification degree of the PVA-based resin (A) in the composition. It is preferable from the viewpoint of difficulty in separating the PVA-based resin (A) and the PVA-based resin (B).

  In the composition of the present invention, the content ratio (mass ratio) of the PVA-based resin (A) and the PVA-based resin (B) is not particularly limited, but for example, 1/5 to 5/1, preferably 1/3 to 3 / 1.

The composition of the present invention may contain components other than the PVA-based resin (A) and the PVA-based resin (B), and may contain other resins, additives and the like. It does not specifically limit as another resin, It should just be resin which does not belong to the category of PVA-type resin (A) and PVA-type resin (B).
The additive is not particularly limited, and examples thereof include preservatives, chelating agents, surfactants and the like. In addition, although a laser absorber may be contained as an additive, it is more preferable not to use a laser absorber.

In the composition of the present invention, the content ratio of the other resin is not particularly limited, and for example, 100 parts by mass of the total amount of PVA resin (A) or PVA resin (A) and PVA resin (B) , 0.1 to 20 parts by mass, and the like.
Further, in the composition of the present invention, the content ratio of the additive is not particularly limited, and for example, 100 parts by mass of the total amount of PVA resin (A) or PVA resin (A) and PVA resin (B) And 0.1 to 10 parts by mass.

The composition of the present invention may contain water.
The content of water is not particularly limited, but it is, for example, 100 to 2000 parts by mass, preferably 200 based on 100 parts by mass of the total amount of PVA resin (A) or PVA resin (A) and PVA resin (B). -1500 parts by mass.

The composition of the present invention may contain an organic solvent.
The organic solvent is not particularly limited. For example, alcohols {eg, monohydric alcohols (eg, monohydric alcohols (eg, methanol, ethanol, propanol, butanol etc.), polyhydric alcohols (eg, ethylene glycol, diethylene glycol, propylene glycol etc.)}, alkyl Carboxylic acid esters (eg methyl 3-methoxy propionate and ethyl 3-ethoxy propionate etc), polyhydric alcohol derivatives [eg polyhydric alcohol monoalkyl ethers {eg ethylene glycol monoalkyl ethers (eg Ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether etc., propylene glycol monoalkyl Ether (eg, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, etc.)}, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether acetate, etc. And the like, with preference given to propylene glycol monomethyl ether and the like.
One or more of these can be used.

  The content of the organic solvent is not particularly limited, but is, for example, 5 to 1500 parts by mass, preferably 100 parts by mass with respect to the total amount of the PVA-based resin (A) or the PVA-based resin (A) and the PVA-based resin (B). 10 to 1000 parts by mass.

  The viscosity of the composition of the present invention is not particularly limited, but it is preferably 10 to 500 mPa · s, for example, from the viewpoint that the viscosity at 20 ° C. measured using a B-type rotational viscometer is suitable for spin coating on semiconductors. Is 30 to 400 mPa · s or the like.

  In the composition of the present invention, the content of metal impurities (for example, Na, K, Fe, Cu, etc.) is preferably 50 ppb or less, more preferably 30 ppb or less. The amount of metal impurities can be measured by a known method using, for example, ICP-MS (inductively coupled plasma mass spectrometry) or the like.

When the composition of the present invention contains water and / or an organic solvent, it is preferable that the amount of insoluble components (for example, insoluble PVA-based resin) be as small as possible.
Even when the insoluble component is contained, the maximum particle diameter of the insoluble component in the solution is preferably as small as possible. The maximum particle size of the insoluble component in the solution is, for example, 3 μm or less, preferably 2.5 μm or less, and more preferably 2 μm or less. The method of measuring the maximum particle size is not particularly limited, and may be a conventionally known method.

[semiconductor]
The semiconductor wafer to which the protective agent of the present invention is applied is not particularly limited. For example, a functional film (a functional film for forming a circuit) and an insulating film (for example, a SiO ₂ film) on the surface of a semiconductor substrate (eg, silicon etc.) Etc.) can be used. In particular, a semiconductor wafer having a low-k film (low relative dielectric constant film) is preferable. In the case of a semiconductor wafer having a low-k film, the low-k film itself is a porous film and is often susceptible to mechanical damage. Therefore, when a conventional blade dicing method is applied, the yield of semiconductor devices is increased by mechanical damage. Although the temperature is lowered, semiconductor devices can be manufactured with high yield by using the laser dicing method.

A protective film can be formed by applying the protective agent or composition of the present invention on a semiconductor wafer. The coating method is not particularly limited, and for example, a conventionally known spin coater method can be used. After the protective agent or composition of the present invention is applied onto a semiconductor wafer, a protective film can be generally formed by drying the coated film by heating or the like. The drying method is not particularly limited, and conventionally known methods can be used.
The thickness of the protective film is not particularly limited and may be appropriately adjusted depending on the asperity shape of the semiconductor surface to be applied, and is, for example, 0.01 to 10 μm.

  The protective agent or composition of the present invention may be subjected to an ion exchange treatment in the production process or before the protective agent or composition is applied on a semiconductor wafer. Although the ion exchange treatment method is not particularly limited, for example, it can be carried out by passing the protective agent or composition of the present invention through a column packed with an ion exchange resin or the like. By performing ion exchange treatment before coating on a semiconductor wafer, metal impurities in the protective agent or the composition can be removed, and the metal impurity content in the composition can be brought into the above range. .

  In addition, the protective agent or composition of the present invention may be filtered in the manufacturing process or before applying the protective agent or composition onto a semiconductor wafer. The filtration method is not particularly limited, and the filtration can be performed using a filter or the like. As a filter, for example, one having a pore diameter of 1 μm or less can be used.

A groove can be formed in the semiconductor wafer by performing laser dicing by irradiating a laser beam from the surface of the protective film of the semiconductor wafer on which the protective film is formed. The method of laser dicing is not particularly limited, and conventionally known methods can be used.
The wavelength of the laser light is not particularly limited, and may be, for example, 266 nm, 355 nm, 532 nm, 1064 nm, and the like. Generally, laser light having a wavelength of 355 nm or 532 nm is used for laser dicing of a semiconductor silicon substrate.

After the laser dicing, the semiconductor wafer is washed with water, whereby the protective film and debris generated by the laser dicing can be removed.
The method of washing with water is not particularly limited, and the washing may be carried out using water or warm water (for example, water at 40 to 90 ° C.).

After washing with water, a semiconductor chip can be obtained by cutting the semiconductor wafer along the grooves formed by laser dicing. The cutting method is not particularly limited, and conventionally known cutting devices can be used.
As described above, since the debris in the semiconductor wafer is removed by water washing, it is possible to obtain a semiconductor chip free from the deposition of debris.

  EXAMPLES The present invention will be described in more detail by way of the following examples, but the present invention is not limited by these examples.

[PVA (A1)]
After impregnating and swelling 100 parts by weight of JP-03 (saponification degree 88 mol%, average polymerization degree 300) 100 parts by weight of vanillin in 200 parts by weight of methanol for 60 minutes and swelling Then, 25 parts by weight of 1N aqueous hydrochloric acid solution was added, and the reaction was performed at 40 ° C. for 2 hours. Subsequently, it was neutralized with 25 parts by weight of a 1N aqueous solution of sodium hydroxide. Subsequently, the solvent was removed by centrifugation, followed by drying at 80 ° C. for 4 hours in a nitrogen atmosphere to obtain a PVA-based polymer (A1). The PVA-based polymer (A1) was dissolved in d6-DMSO solvent and subjected to ¹ H-NMR measurement, and the degree of modification was 3.5 mol%.

[PVA (B1)]
As PVA (B1), JP-08 (Saponification degree: 88 mol%, average polymerization degree: 800) manufactured by Nippon Shokubai Bi-Poval, Inc. was used.

[PVA (B2)]
As the PVA (B2), JP-03 (saponification degree: 88 mol%, average polymerization degree: 300) manufactured by Japan Venetian-Poval Co., Ltd. was prepared.

Example 1
[Preparation of Protective Agent Composition 1]
69.5 parts by weight of ultrapure water, 10.0 parts by weight of propylene glycol monomethyl ether (PGME), 15.0 parts by weight of PVA (A1), and 5.3 parts by weight of PVA (B1) were adjusted. The solution was dissolved by heating at 70 ° C. for 60 minutes.
The solution after heating and dissolution was cooled to room temperature, and then passed through a column filled with a mixed ion exchange resin (Orlite, Orlite-DS3 manufactured by Organo Corporation) consisting of an anion exchange resin and a cation exchange resin.
Further, it was filtered with a filter with a pore size of 1 μm manufactured by Advantec Co., Ltd. to remove foreign matter, to obtain a protective agent composition 1.
The viscosity at 20 ° C. of the above protective agent composition 1 measured using a B-type rotational viscometer was 270 mPa · s. Moreover, the light absorbency in 355 nm of the aqueous solution which diluted the protective agent composition 1 100 times was 0.15.

[Laser dicing process]
The protective agent composition 1 was spin-coated on the surface of a semiconductor substrate on which a low-k film was laminated so that the film thickness would be 1 μm, and laser dicing was performed using a laser dicing apparatus having a wavelength of 355 nm. The protective film was not peeled off at the periphery of the laser dicing area, and the adhesion of debris to the substrate was prevented. Even after washing with water, adhesion of debris to the base plate was not observed.

Comparative Example 1
[Preparation of Protective Agent Composition 2]
74.5 parts by weight of ultrapure water, 10.0 parts by weight of propylene glycol monomethyl ether (PGME), 10.0 parts by weight of PVA (B2), and 5.5 parts by weight of PVA (B1) were prepared. The solution was dissolved by heating at 70 ° C. for 60 minutes.
The solution after heating and dissolution was cooled to room temperature, and then passed through a column filled with a mixed ion exchange resin (Orlite, Orlite-DS3 manufactured by Organo Corporation) consisting of an anion exchange resin and a cation exchange resin.
Further, it was filtered with a filter with a pore size of 1 μm manufactured by Advantec Co., Ltd. to remove foreign matter, to obtain a protective film composition 2.
The viscosity at 20 ° C. of the above protective agent composition 2 measured using a B-type rotational viscometer was 271 mPa · s. Moreover, the light absorbency in 355 nm of the aqueous solution which diluted the protective agent composition 100 times was 0.01.

[Laser dicing process]
The protective agent composition 2 was spin-coated on the surface of a semiconductor substrate on which a low-k film was laminated so that the film thickness would be 1 μm, and laser dicing was performed using a laser dicing apparatus having a wavelength of 355 nm. Peeling of the protective film was observed around the laser dicing site, and adhesion of debris to the substrate was observed. Furthermore, adhesion of debris to the base plate was observed even after washing with water.

  As described above, when the PVA-based resin (A) having an ultraviolet absorbing group is used as a protective agent, the protective film does not peel off at the periphery of the laser dicing location, and the adhesion of debris to the base plate is When a PVA-based resin (B) having no ultraviolet absorbing group was used as a protective agent, the protective film peeled off at the periphery of the laser dicing location, debris adhered to the substrate, and washing with water was not observed. Adhesion of debris to the base plate was also observed after that.

  By forming a protective film on the surface of a semiconductor wafer using the protective agent of the present invention and then performing laser dicing, debris generated by laser dicing can be removed together with the protective film by water washing, so the protection of the present invention The agent is very useful industrially.

Claims (19)

UV-absorbing group composed of polyvinyl alcohol resin (A) having a protective agent for protecting semiconductor from debris adhering to the surface when laser dicing the semiconductor (although, polyvinyl alcohol resin (A) is Except when it is photocrosslinkable) . A protective agent composed of a polyvinyl alcohol resin (A) having an ultraviolet absorbing group, which protects the semiconductor from adhesion of debris to the surface when laser dicing the semiconductor, wherein the ultraviolet absorbing group is benzaldehyde, A protecting agent which is a group derived from at least one or more kinds of aldehydes selected from the group consisting of benzaldehyde compounds having a hydroxyl group, benzaldehyde compounds having a nitro group, naphthaldehyde compounds and cinnamaldehyde . UV absorbing group, coercive Mamoruzai according to claim 1, wherein the group derived from a carbonyl compound having an ultraviolet absorbing group. Carbonyl compound, coercive Mamoruzai of claim 3 wherein the aldehyde. Aldehydes, carbon - coercive Mamoruzai of claim 4, wherein the carbon double bond is two or more with aldehydes. The aldehyde is selected from the group consisting of 4-hydroxybenzaldehyde, 2,4-dihydroxybenzaldehyde, 3,4-dihydroxybenzaldehyde, vanillin, 4-nitrobenzaldehyde, 1-naphthaldehyde, 2-hydroxy-1-naphthaldehyde and cinnamaldehyde at least one coercive Mamoruzai according to any one of claims 2, 4 and 5 is to be. Coercive Mamoruzai according to any one of claims 1-6 saponification degree of the polyvinyl alcohol-based resin (A) is 60 mol% or more. Coercive Mamoruzai according to any one of claims 1-7 average polymerization degree of the polyvinyl alcohol-based resin (A) is 100 to 4000. Modification degree of the polyvinyl alcohol-based resin (A), the coercive Mamoruzai according to any one of claims 1-8 is 0.1 to 10 mol%. Including the coercive Mamoruzai according to any one of claims 1 to 9 compositions for protecting semiconductor semiconductor when laser dicing from the debris adhering to the surface. The composition according to claim 10 , further comprising a polyvinyl alcohol resin (B) different from the polyvinyl alcohol resin (A). The composition according to claim 11 , wherein the saponification degree of the polyvinyl alcohol resin (B) is within ± 3 mol% of the saponification degree of the polyvinyl alcohol resin (A). The composition according to claim 11 or 12 , wherein the average degree of polymerization of the polyvinyl alcohol resin (B) differs from that of the polyvinyl alcohol resin (A) by 100 or more. The composition according to any one of claims 10 to 13 , further comprising water. The compositions according to any one of 10-14, containing the organic solvent. The composition according to any one of claims 10 to 15 , wherein the content of metal impurities is 50 ppb or less. The composition according to any one of claims 14 to 16 , wherein the maximum particle size of the insoluble component in the solution is 3 μm or less. A method for producing a composition , comprising the step of deionizing the composition according to any one of claims 10 to 17 by ion exchange treatment. Comprising the step of filtering the composition a pore size 1μm following filter according to any of claims 10-17, production process of the composition.