JP6533149B2 - 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 have found that polyvinyl alcohol resins having at least two carbon-carbon double bonds per molecule of polyvinyl alcohol resin (hereinafter referred to as PVA) The resin is coated on the surface of the semiconductor wafer to form a protective film, and then laser dicing is performed. In addition to the polyvinyl alcohol resin having at least two carbon-carbon double bonds, a laser absorbing agent It has been found that the adhesion of debris to the semiconductor surface can be efficiently prevented without using water, and the washing generated after laser dicing 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 at least two carbon-carbon double bonds per molecule of polyvinyl alcohol resin.
[2] The protective agent for semiconductor laser dicing according to the above [1], wherein the degree of saponification of the polyvinyl alcohol resin (A) is 60 mol% or more.
[3] The protective agent for semiconductor laser dicing according to the above [1] or [2], wherein the average degree of polymerization of the polyvinyl alcohol resin (A) is 100 to 4000.
The absorbance at 355 nm of the polyvinyl alcohol resin (A) is 0.03 or more when the 0.1 mass% aqueous solution of the polyvinyl alcohol resin (A) is measured at an optical path length of 1 cm. The protective agent for semiconductor laser dicing in any one of [3].
[5] A composition comprising the protective agent for semiconductor laser dicing according to any one of the above [1] to [4].
[6] The composition according to the above [5], further comprising a polyvinyl alcohol resin (B) different from the polyvinyl alcohol resin (A).
[7] The composition according to [6], 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).
[8] The composition according to the above [6] or [7], 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.
[9] The composition according to any one of the above [5] to [8], further containing water.
[10] The composition according to any one of the above [5] to [9], which further contains an organic solvent.
[11] The composition according to any one of the above [5] to [10], wherein the content of metal impurities is 50 ppb or less.
[12] The composition according to any one of the above [9] to [11], wherein the maximum particle size of the insoluble component in the solution is 3 μm or less.
[13] A method for producing a semiconductor, comprising the step of deionizing the composition according to any one of [5] to [12] by ion exchange treatment.
[14] A method for producing a semiconductor, comprising the step of filtering the composition according to any one of the above [5] to [12] with a filter having a pore diameter 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 composed of a PVA-based resin (A) having at least two carbon-carbon double bonds per molecule of polyvinyl alcohol-based resin.

[PVA-based resin (A)]
The PVA-based resin (A) is not particularly limited as long as it has at least two carbon-carbon double bonds per molecule of polyvinyl alcohol-based resin.
In the PVA-based resin (A), the number of carbon-carbon double bonds is, for example, 2 or more (for example, 2 to 10), preferably 2 to 8 (for example, 2 to 6), and more preferably 2 to 4 (for example) For example, it may be about 2 to 3).
In the PVA-based resin (A), the position of the carbon-carbon double bond is not particularly limited, but usually at least α, β positions with respect to the carbonyl group (that is, when the carbonyl carbon is 1 position) ) May be.
Further, in the PVA-based resin (A), the positional relationship between a plurality of double bonds is not particularly limited, but in particular, a plurality of carbon-carbon double bonds form a conjugated system (in particular, a conjugated system together with a carbonyl group) Preferably). In addition, the carbonyl group may form a conjugated system with the aromatic ring.

As described later, the PVA-based resin (A) is produced, for example, through the step of polymerizing a raw material monomer (vinyl ester-based monomer) in the presence of a carbonyl compound.
In such a polymerization step, a carbonyl group derived from a carbonyl compound is introduced into the polymer (for example, a molecular end, a main chain end) by chain transfer or the like, but this carbonyl group is subjected to heat treatment during or after polymerization. A carbon-carbon double bond may be introduced so as to form a conjugated system as in the α, β positions (and furthermore, the γ, δ positions).

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 carbon-carbon double bond at a position of α, β and γ, δ with respect to a carbonyl group Using a PVA-based resin (A1) having at least one carbon-carbon double bond at positions α, β, γ, δ and ε, に 対 し て with respect to a carbonyl group (A1 etc.) In this case, it is preferable that the average degree of polymerization of the PVA resin (A2) is 100 or more (e.g., 100 to 1000) larger than the average degree of polymerization of the PVA resin (A1).

The (average) saponification degree of the PVA-based resin (A) is not particularly limited, but preferably 60 mol% or more (for example, 60 to 100 mol%) from the viewpoint of easy removal of the protective film by water washing More preferably, it is 65 to 95 mol%, further 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 absorption wavelength in the ultraviolet absorption spectrum of the PVA-based resin (A) is not particularly limited as long as it has absorption in the wavelength of the laser beam to be used, and can be appropriately changed according to the wavelength of the laser beam to be used.
The absorption wavelength in the ultraviolet absorption spectrum of the PVA-based resin (A) is, for example, 355 nm. When a 0.1 mass% aqueous solution of PVA resin (A) is measured at an optical path length of 1 cm, the absorbance of the desired absorption wavelength (for example, 355 nm) in the ultraviolet absorption spectrum is, for example, 0.01 or more, preferably 0.03. The above, more preferably 0.04 or more.
In the present invention, the method of measuring the ultraviolet absorption spectrum is not particularly limited, and may be in accordance with a conventionally known method.
The PVA-based resin (A) only needs to have the wavelength of the laser light as the absorption wavelength. For example, when the absorption wavelength is 355 nm, the maximum absorption wavelength may not be 355 nm. For example, when the PVA-based resin (A) has three carbon-carbon double bonds, it may have a maximum absorption wavelength in the vicinity of 325 nm.

[Method of producing PVA-based resin (A)]
The method for producing the PVA-based resin (A) is not particularly limited. For example, a vinyl ester-based polymer (a) obtained at least through the step of polymerizing a vinyl ester-based monomer in the presence of an aldehyde and / or a ketone Can be obtained by saponification reaction.

  The polymerization method of the vinyl ester polymer (a) is not particularly limited, and may be in accordance with the conventionally known method of vinyl ester polymer. As the polymerization method, for example, solution polymerization can be mentioned, and in consideration of control of polymerization degree, saponification reaction performed after polymerization, solution polymerization using methanol as a solvent, or water or water and methanol as a dispersion medium Suspension polymerization is preferred but is not limited thereto.

  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 aldehyde is not particularly limited. For example, formaldehyde, aliphatic aldehyde {eg, saturated aliphatic aldehyde (eg, alkyl aldehyde having 2 to 20 carbon atoms such as acetaldehyde, propionaldehyde, butyraldehyde, etc.), unsaturated aliphatic Aldehydes (eg, alkenyl aldehydes having 3 to 20 carbon atoms), alicyclic aldehydes (eg, cycloalkyl aldehydes having 3 to 20 carbon atoms, etc.), aromatic aldehydes (eg, benzaldehyde, naphthaldehydes, etc.) Preferably it is an aliphatic aldehyde, More preferably, it is a C2-C10 alkyl aldehyde, More preferably, it is acetaldehyde. One or more of these aldehydes can be used.

  In the polymerization of the vinyl ester polymer (a), the amount of aldehyde used is not particularly limited, and is appropriately adjusted in order to obtain a polymer having a target polymerization degree.

In polymerization of the vinyl ester polymer (a), as long as the effects of the present invention are exhibited, other monomers other than the aldehyde and the vinyl ester monomer may be copolymerized.
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 used, 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.

  In the polymerization of the vinyl ester polymer (a), an additive (for example, a polymerization catalyst etc.) which can be used in the polymerization of the vinyl ester polymer may be used.

A PVA-based resin (A) can be obtained by subjecting the vinyl ester-based polymer (a) obtained as described above to a saponification reaction.
The saponification reaction method is not particularly limited, and may be a conventionally known method. As a saponification reaction method, for example, a conventionally known basic catalyst (for example, sodium hydroxide, potassium hydroxide, sodium methoxide, tetramethylammonium hydroxide (TMAH) or the like) or an acidic catalyst (for example, hydrochloric acid, sulfuric acid, An alcoholysis or hydrolysis reaction using p-toluenesulfonic acid etc.) can be applied. From the viewpoint of using for a protective film for laser processing of a semiconductor, it is preferable that the amount of metal impurities be smaller, and it is preferable to use TMAH.
Examples of the solvent used for the saponification reaction include alcohols (eg, methanol, ethanol etc.), esters (eg, methyl acetate, ethyl acetate etc.), ketones (eg, acetone, methyl ethyl ketone etc.), aromatic hydrocarbons (eg, For example, benzene, toluene and the like can be mentioned, and these can be used alone or in combination of two or more.

  The PVA-based resin (A) may be polymerized using, for example, the polymerization method of PVA described in JP-A-51-45189 or JP-A-49-53270.

The PVA-based resin (A) can be obtained as described above, but in order to increase the number of double bonds, it is preferable to further carry out heat treatment. By performing the heat treatment, the content ratio and the number of double bonds in the PVA-based resin (A) can be adjusted.
The heating method is not particularly limited, but it is preferable to carry out under a vacuum condition or under a nitrogen atmosphere.
Although a heating temperature is not specifically limited, For example, 100 degreeC or more (for example, 100-180 degreeC), Preferably it is 100-160 degreeC etc.
The heating time can be appropriately selected depending on the heating temperature and the physical properties (for example, the absorption wavelength in the ultraviolet absorption spectrum) of the target PVA-based resin (A), etc., and is not particularly limited. It is time etc.

[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. The PVA-based resin (B) may be a common PVA-based resin, or may be a precursor before introducing a carbon-carbon double bond in the production of the PVA-based resin (A).

[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 carbon-carbon double bond at a position of α, β and γ, δ with respect to a carbonyl group Use of a PVA-based resin (A) having at least one carbon-carbon double bond at positions α, β, γ, δ and ε, に 対 し て with respect to a carbonyl group. In this case, the average degree of polymerization of the PVA-based resin (B) is preferably 100 or more (e.g., 100 to 1000) greater than the average degree of polymerization of the PVA-based resin (A).

The (average) saponification degree of the PVA-based resin (B) is not particularly limited, but preferably 60 mol% or more (for example, 60 to 100 mol%), from the viewpoint of easy removal of the protective film by water washing, etc. More preferably, it is 65 to 95 mol%, further 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).
Moreover, it does not specifically limit as an additive, For example, antiseptic | preservative, a chelating agent, surfactant, etc. are mentioned. 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, based on 100 parts by mass of the total amount of PVA resin (A) or PVA resin (A) and PVA resin (B), for example It is 0.1-20 mass parts etc.
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 0.001 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.

  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)]
As a PVA in which an aldehyde is introduced at the terminal, CR-03 (saponification degree 72 mol%, average polymerization degree 300, two carbon-carbon double bonds near the terminal has a conjugation 2), manufactured by Nippon Shokubai Bi-Poval KK This was subjected to heat treatment at 150 ° C. for 3 hours in a vacuum environment using a heavy bond) to obtain PVA (A1).
In addition, about the number of double bonds, the < ¹ > H-COSY spectrum was measured and it identified by the known method (1989 polymer processing 38 volumes 8 page 29-30).

[PVA (A2)]
CR-08 (manufactured by Nippon Shokubai Bi-Poval Co., Ltd., CR-8 (saponification degree 72 mol%, average degree of polymerization 800, carbon-carbon double bond near the end) which is a PVA introduced with an aldehyde at the end as PVA (A2) It has two and is used as a conjugated double bond).

[PVA (B1)]
This was heat-treated at 150 ° C. for 3 hours in a vacuum environment using JR 03 (saponification degree: 72 mol%, average polymerization degree: 300) manufactured by Nippon Shokubai Bi-Poval Co., Ltd. to obtain PVA (B1).

[PVA (B2)]
As PVA (B2), JR-08 (Saponification degree: 72 mol%, average polymerization degree: 800) manufactured by Nippon Shokubai Bi-Poval KK was used.

Example 1
[Preparation of Protective Agent Composition 1]
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 (A1), and 5.5 parts by weight of PVA (A2) The solution was heated to dissolve 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 275 mPa · s. Moreover, the light absorbency in 355 nm of the aqueous solution which diluted the protective agent composition 1 100 times was 0.43. In addition, the measurement of the light absorbency was measured by 1 cm of optical path lengths using the ultraviolet visible visible altimeter V-750 made from Jusco engineering corporation | Co., Ltd. | KK.

[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 (B1), and 5.5 parts by weight of PVA (B2) The solution was heated to dissolve 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 diameter of 1 μm manufactured by Advantec Co., Ltd. to remove foreign substances, to obtain a protective agent composition 2.
The viscosity at 20 ° C. of the above protective agent composition 2 measured using a B-type rotational viscometer was 273 mPa · s. Moreover, the light absorbency in 355 nm of the aqueous solution which diluted the protective agent composition 2 100 times was 0.04. In addition, the measurement of the light absorbency was measured by 1 cm of optical path lengths using the ultraviolet visible visible altimeter V-750 made from Jusco engineering corporation | Co., Ltd. | KK.

[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 at least two carbon-carbon double bonds is used as a protective agent, the protective film does not peel off at the periphery of the laser dicing location, and the base is also washed with water. While no adhesion of debris to the plate was observed, when a PVA-based resin (B) having no carbon-carbon double bond was used as a protective agent, the protective film peeled off around the laser dicing location. Debris adhered to the substrate, and adhesion of debris to the base plate was observed even after washing with water.

  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 (16)

Carbon - protection carbon double bond, formed by a polyvinyl alcohol-based resin having at least two (A) to 1 per molecule polyvinyl alcohol-based resin, a semiconductor from debris adhering to the surface of the semiconductor at the time of laser dicing protective agent for (unless polyvinyl alcohol resin (a) is a photo-crosslinkable).   A carbon-carbon double bond is composed of a polyvinyl alcohol-based resin (A) having at least two or more carbonyl groups per molecule of polyvinyl alcohol-based resin, and when semiconductors are laser-diced, the semiconductor is applied to the surface Protective agent to protect from the adhesion of debris.   The protecting agent according to claim 2, wherein the polyvinyl alcohol resin (A) has a carbon-carbon double bond at least in the α, β positions with respect to the carbonyl group. Coercive Mamoruzai according to any one of claims 1-3 saponification degree is 60 mol% or more of polyvinyl alcohol resin (A). Coercive Mamoruzai according to any one of claims 1-4 average polymerization degree of the polyvinyl alcohol-based resin (A) is 100 to 4000. Absorbance at 355nm of the polyvinyl alcohol-based resin (A), in case of measuring a polyvinyl alcohol-based resin (A) 0.1 wt% aqueous solution at an optical path length 1 cm, claim 1-5 is 0.03 or more coercive Mamoruzai described. Compositions for protecting semiconductor when laser dicing a semiconductor including coercive Mamoruzai according the debris adhering to the surface in any of claims 1-6. The composition according to claim 7 , further comprising a polyvinyl alcohol resin (B) different from the polyvinyl alcohol resin (A). The composition according to claim 8 , 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 8 or 9 , 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 7 to 10 , further comprising water. The composition according to any one of claims 7 to 11 , further comprising an organic solvent. The composition according to any one of claims 7 to 12 , wherein the content of metal impurities is 50 ppb or less. The composition according to any one of claims 11 to 13 , wherein the maximum particle size of the insoluble component in the solution is 3 μm or less. A method of producing a composition , comprising the step of deionizing the composition according to any one of claims 7 to 14 by ion exchange treatment. Comprising the step of filtering the composition a pore size 1μm following filter according to any of claims 7 to 14, the production method of the composition.