Protective film composition for dicing, wafer manufacturing method, and wafer processing method

Abstract

To provide a protective film composition for dicing which can suppress temporal lowering of absorbance, and can suppress temporal increase in the number of defects, and a wafer manufacturing method and a wafer processing method which use the same.SOLUTION: A protective film composition for dicing contains an ultraviolet absorber containing a compound (1) represented by the following general formula (1), a water-soluble resin, formic acid ions, and water, and the content of the formic acid ions is 300 to 6,000 mass ppm. In the formula, X represents a hydrogen atom, and -OR1; R1 represents a substituted or unsubstituted alkyl group having 1 to 5 carbon atoms; n represents the number of 1 to 5; and m represents the number of 0 to 4.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a protective film composition for dicing, a method for manufacturing a wafer, and a method for processing a wafer.

Background Art

[0002] A wafer formed in a semiconductor device manufacturing process is a laminate in which an insulating film and a functional film are laminated on the surface of a semiconductor substrate such as silicon, and is partitioned by a grid-like division planned line called a street. Each region partitioned by the street is a semiconductor chip such as an IC or an LSI. That is, a plurality of semiconductor chips can be obtained by processing and cutting the wafer along this street.

[0003] Processing and cutting of the wafer are performed, for example, by laser dicing or the like. When performing laser dicing, a protective film for dicing is provided on the surface of the wafer in order to prevent the adhesion of debris. As a technique related to such a protective film for dicing, for example, Patent Document 1 discloses a protective film agent for laser dicing characterized by comprising a solution in which a water-soluble resin and at least one water-soluble laser light absorber selected from the group consisting of a water-soluble dye, a water-soluble pigment, and a water-soluble ultraviolet absorber are dissolved.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The protective film for dicing prevents the adhesion of debris generated during dicing as described above, but there is still room for improvement in its performance.

[0006] First, some compositions for forming a dicing protective film (dicing protective film compositions) contain an absorbent that absorbs the laser light used during dicing. However, there is a problem in that the absorbance decreases over time as the number of days of storage elapses. If the absorbance decreases unintentionally, it becomes impossible to perform precise cutting with a laser beam along a streamline, or it becomes difficult to perform laser processing with a uniform line width.

[0007] Next, after cutting a wafer protected by a dicing protective film by laser dicing, the dicing protective film is removed by cleaning. In recent years, in order to fabricate a precise structure, defect management on a substrate has become stricter, and therefore, it is required to further improve surface defects after protective film cleaning. However, in the conventional dicing protective film composition, there has been a problem that residues after substrate cleaning deteriorate over time.

[0008] The present invention has been made in view of the above circumstances, and a main object thereof is to provide a dicing protective film composition capable of suppressing a decrease in absorbance over time and suppressing an increase in the number of defects over time, a method for manufacturing a wafer using the same, and a method for processing a wafer.

Means for Solving the Problems

[0009] As a result of intensive studies to achieve the above-described object, the present inventors have found that an ultraviolet absorber containing a compound (1) having a specific structure, a water-soluble resin, formate ions, and water are contained, and the content of formate ions is 300 to 6000 mass ppm, and have completed the present invention by obtaining a dicing protective film composition.

[0010] That is, the present invention is as follows. <1> A dicing protective film composition containing an ultraviolet absorber containing a compound (1) represented by the following general formula (1), a water-soluble resin, formate ions, and water, wherein the content of the formate ions is 300 to 6000 mass ppm.

[0011]

Chem.

[0012] (wherein X represents a hydrogen atom, -OR 1 represents. R 1 represents a substituted or unsubstituted alkyl group having 1 to 5 carbon atoms. n represents a number from 1 to 5, and m represents a number from 0 to 4.) <2> The ultraviolet absorber is at least one selected from the group consisting of ferulic acid, 2-hydroxycinnamic acid, 4-hydroxycinnamic acid, 2,3-dihydroxycinnamic acid, and 3,4-dihydroxycinnamic acid, and is the dicing protective film composition according to <1>. <3> The water-soluble resin is at least one resin selected from the group consisting of resin (2a) containing a structural unit represented by the following formula (2a-1) and a structural unit represented by the following formula (2a-2), and resin (2b) containing a structural unit represented by the following formula (2b), and is the dicing protective film composition according to <1> or <2>.

[0013]

Chem.

[0014] <4> Furthermore, it contains an aqueous organic solvent and is the dicing protective film composition according to any one of <1> to <3>. <5> The aqueous organic solvent is at least one selected from the group consisting of glycol solvents and alcohol solvents, and is the dicing protective film composition according to <4>. <6> The aqueous organic solvent contains two or more aqueous organic solvents and is the dicing protective film composition according to <4> or <5>. <7> It is a dicing protective film composition according to any one of <1> to <6> with a solid content concentration of 1 to 90% by mass. <8> A wafer manufacturing method including a film forming step of applying a dicing protective film composition according to any one of <1> to <7> to a processed surface of a wafer to form a protective film, and a processing step of irradiating the processed surface with laser light through the protective film for processing. <9> The wafer has a plurality of semiconductor chips partitioned by grid-like streets, and the processing step is a step of forming grooves by irradiating the streets with laser light through the protective film. The wafer manufacturing method according to <8>. <10> The wafer manufacturing method according to <8> or <9>, including a step of removing the protective film by water washing after the processing step. <11> A wafer processing method including a film forming step of applying a dicing protective film composition according to any one of <1> to <7> to a processed surface of a wafer to form a protective film, and a processing step of irradiating the processed surface with laser light through the protective film for processing.

Advantages of the Invention

[0015] According to the present invention, it is possible to provide a dicing protective film composition capable of suppressing a decrease in absorbance over time and an increase in the number of defects over time, and a wafer manufacturing method and a wafer processing method using the same.

Embodiments for Carrying Out the Invention

[0016] Hereinafter, embodiments for carrying out the present invention (hereinafter simply referred to as "the present embodiment") will be described in detail. The following present embodiment is an exemplification for explaining the present invention and is not intended to limit the present invention to the following contents. The present invention can be appropriately modified and implemented within the scope of its gist.

[0017] <Dicing Protective Film Composition>

[0018] The dicing protective film composition according to this embodiment contains an ultraviolet absorber containing a compound (1) represented by the following general formula (1), a water-soluble resin, formate ions, and water, and is a dicing protective film composition in which the content of formate ions is 300 to 6000 mass ppm.

[0019]

Chemical formula

[0020] (In the formula, X represents a hydrogen atom, -OR 1 represents. R 1 represents a substituted or unsubstituted alkyl group having 1 to 5 carbon atoms. n represents a number from 1 to 5, and m represents a number from 0 to 4.)

[0021] By containing an ultraviolet absorber having the structure of general formula (1) and a water-soluble resin and controlling the content of formate ions, at least a decrease in absorbance over time can be suppressed, and an increase in the number of defects over time can be suppressed. For example, when the absorbance fluctuates, the absorption wavelength changes, but by controlling the content of formate ions in the dicing protective film composition according to this embodiment, such a problem can also be suppressed. In addition, when debris is washed and removed with water or the like after laser dicing, if debris adhering to the surface of the wafer remains without being removed by the washing, this may cause a problem that the number of defects increases over time, but according to the dicing protective film composition according to this embodiment, such a problem can also be suppressed.

[0022] Hereinafter, various components and the like of the dicing protective film composition according to this embodiment will be described.

[0023] (Ultraviolet Absorber)

[0024] Compound (1) has the structure of general formula (1). The hydroxy group (-OH) in general formula (1) may be dissociated and present in the composition which is a solution. Also, compound (1) may be formulated as its salt. The type of the salt of compound (1) is not particularly limited, but from the viewpoints of water solubility and compatibility with other components, etc., it may be at least one selected from the group consisting of alkali metal salts (such as lithium salt, sodium salt, potassium salt, etc.) and their hydrates. By using compound (1) having such a structure, peeling of the film during laser processing can be suppressed, so that adhesion of debris can be effectively prevented. For example, when irradiated with laser light, thermal decomposition of the substrate proceeds prior to thermal decomposition of the protective film, and voids are formed in the protective film and the peripheral portion (near the street line) of the chip surface due to the pressure of silicon vapor or the like which is the thermal decomposition product (that is, partial peeling of the protective film occurs at the peripheral portion), and as a result, it is considered that debris adheres to the peripheral portion of the chip surface. In this regard, according to the present embodiment, by using the above compound (1) in combination with a water-soluble resin and formate ions in a specific content, etc., such adhesion of debris can be effectively suppressed.

[0025] The hydroxy group (-OH) bonded to the benzene ring of compound (1) is preferably at the para position and / or ortho position of the acrylic acid group (-C=C-COOH). When there are two or more hydroxy groups, at least one of them is preferably at the para position and / or ortho position. With such a structure, it becomes easy to form a resonance structure or a dimer that can effectively suppress the decrease in absorbance over time (however, the actions and effects according to the present embodiment are not limited thereto).

[0026] X in general formula (1) may be a hydrogen atom or -OR 1 and is preferably a hydrogen atom.

[0027] When X in general formula (1) is -OR 1 then R 1is a substituted or unsubstituted alkyl group having 1 to 5 carbon atoms. The lower limit of the number of carbon atoms may be 2 or more. The upper limit of the number of carbon atoms may be 4 or less.

[0028] R 1 When R is a substituted alkyl group (alkyl group having a substituent), examples of the substituent include a halogen atom (such as a chloro group, a bromo group, an iodo group, etc.), a hydroxy group, a carbonyl group, a carboxy group, a nitro group, an amino group, a sulfo group, and the like.

[0029] R 1 When R is a substituted or unsubstituted alkyl group, examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, an n-pentyl group, an isopentyl group, a tert-pentyl group, and the like. Among these, a methyl group is preferred. When X is -OR 1 For a preferred example, a methoxy group (-OCH3) can be mentioned.

[0030] n is a number from 1 to 5, preferably from 1 to 4, more preferably from 1 to 3, and still more preferably 1 or 2.

[0031] m is a number from 0 to 4. However, when X is a -OR 1 group, m is preferably from 0 to 3, more preferably from 0 to 2, and still more preferably 0 or 1. When all of X are hydrogen atoms, it is preferable that n + m = 5.

[0032] As the structure of the general formula (1), X is an alkoxy group (such as a methoxy group, etc.), n is 1 or 2, m is 4 or 3, and it is preferable that n + m = 5. With such a structure, peeling of the film during laser processing can be suppressed, and thus adhesion of debris can be more effectively prevented.

[0033] Further, as a preferred example of the type of the ultraviolet absorber, it is preferably at least one selected from the group consisting of ferulic acid, 2-hydroxybenzoic acid, 4-hydroxybenzoic acid, 2,3-dihydroxybenzoic acid, and 3,4-dihydroxybenzoic acid. By being such a compound, peeling of the film during laser processing can be suppressed, and thus adhesion of debris can be more effectively prevented.

[0034] The ultraviolet absorber may be used alone or in combination of two or more.

[0035] The content of the ultraviolet absorber in the dicing protective film composition according to the present embodiment is not particularly limited as long as it does not inhibit the object of the present embodiment, but is preferably 1 to 10 parts by mass with respect to 100 parts by mass of the water-soluble resin in the dicing protective film composition. The lower limit of the content of the ultraviolet absorber with respect to 100 parts by mass of the water-soluble resin in the dicing protective film composition is more preferably 1.5 parts by mass or more, and still more preferably 2 parts by mass or more. Further, the upper limit of the content of the ultraviolet absorber with respect to 100 parts by mass of the water-soluble resin in the dicing protective film composition is more preferably 8 parts by mass or less, and still more preferably 7 parts by mass or less.

[0036] (Water-soluble resin)

[0037] It contains a water-soluble resin. By dissolving it in a solvent such as water or an aqueous medium and then coating and drying, a protective film can be effectively formed. Further, for example, after performing predetermined processing such as laser processing including laser ablation, the protective film can be easily removed by water washing.

[0038] In this specification, the "water solubility" of the water-soluble resin means that, unless otherwise specified, 0.5 g or more of the solute (the resin) dissolves in 100 g of water at 25°C. Note that the water-soluble resin includes a resin solubilized in water by a hydrolysis reaction or treatment with a base in an aqueous medium. For example, as a result of such a reaction or treatment, a resin in which 0.5 g or more of the solute (the resin) can dissolve in 100 g of water at 25°C also falls under the "water-soluble resin" as referred to in this specification.

[0039] The dicing protective film formed on the wafer surface is usually removed from its surface by water washing at an appropriate time after the formation of the processing grooves. Therefore, from the viewpoint of the water washability of the dicing protective film, it is preferably a water-soluble resin having a high affinity for water. From such a viewpoint, as a preferred example of the water-soluble resin, it preferably contains at least one selected from the group consisting of vinyl resins, polyvinyl alcohol resins, and cellulose resins, and more preferably contains at least one selected from the group consisting of vinyl resins and polyvinyl alcohol resins.

[0040] The weight average molecular weight of the water-soluble resin is not particularly limited, but is usually preferably 100 to 300,000. The lower limit of this weight average molecular weight is more preferably 1,000 or more, and still more preferably 10,000 or more. Also, the upper limit of this weight average molecular weight is more preferably 200,000 or less, and still more preferably 150,000 or less. Note that, unless otherwise specified, the weight average molecular weight in this specification refers to the weight average molecular weight (M w ) in terms of polystyrene obtained by gel permeation chromatography (GPC) analysis.

[0041] The type of the water-soluble resin is not particularly limited, but it is preferably at least one selected from the group consisting of polyvinyl alcohol-based resins, vinyl-based resins, and cellulose-based resins. Such a water-soluble resin not only has high water solubility but also high compatibility with other components in the dicing protective film composition, so that changes in absorbance and the number of defects over time can be more effectively suppressed.

[0042] Specific examples of the polyvinyl alcohol-based resin include, for example, polyvinyl alcohol (PVA), polyvinyl acetal (including vinyl acetate copolymers), butanediol-vinyl alcohol copolymer, polyvinyl alcohol-polyacrylic acid block copolymer, polyvinyl alcohol-polyacrylate ester block copolymer, and the like. Among these, polyvinyl alcohol is preferred.

[0043] The vinyl-based resin is preferably a homopolymer of a monomer having a vinyl group or a copolymer of a monomer having a vinyl group and is a water-soluble resin. Specific examples of the vinyl-based resin include, for example, at least one selected from the group consisting of polyvinyl alcohol-based resins, poly-N-vinylacetamide, polyvinylpyrrolidone (PVP), polyacrylamide, poly(N-alkylacrylamide), polyallylamine, poly(N-alkylallylamine), partially amidated polyallylamine, poly(diallylamine), allylamine-diallylamine copolymer, and polyacrylic acid.

[0044] The cellulose-based resin is cellulose or a cellulose derivative, and preferably has water solubility. Examples of the cellulose derivative include those obtained by modifying cellulose with an alkyl group (e.g., methyl group, ethyl group, etc.) or a hydroxyalkyl group (e.g., hydroxymethyl group, hydroxyethyl group, hydroxypropyl group, etc.). Specific examples of the cellulose derivative include at least one selected from the group consisting of methyl cellulose, ethyl cellulose, hydroxymethyl cellulose, hydroxyethyl cellulose, and hydroxypropyl cellulose, etc.

[0045] In addition, as the structure of the water-soluble resin, it is preferably at least one resin selected from the group consisting of resin (2a) containing a structural unit represented by the following formula (2a-1) and a structural unit represented by the following formula (2a-2), and resin (2b) containing a structural unit represented by the following formula (2b). These have a functional group with high affinity for water in the structural unit, and not only have high water solubility but also high compatibility with other components in the dicing protective film composition, so that the change in absorbance over time and the change in the number of defects over time can be more effectively suppressed.

[0046]

Chemical formula

[0047] The water-soluble resin may be used alone or in combination of two or more. Preferred examples of the case of using two or more in combination include, for example, containing at least two selected from the group consisting of polyvinyl alcohol-based resins, vinyl-based resins, and cellulose-based resins. And the above-mentioned various resins can be used. For example, as an example of the case of using two or more of a polyvinyl alcohol-based resin and a vinyl-based resin in combination, the case of containing a polyvinyl alcohol-based resin and a vinyl-based resin can be mentioned. And the mixing ratio (mass ratio) in the case of containing a polyvinyl alcohol-based resin and a vinyl-based resin is not particularly limited, but polyvinyl alcohol:vinyl-based resin may be 10:90 to 90:10, or may be 20:80 to 80:20.

[0048] (Formate ion)

[0049] The dicing protective film composition according to this embodiment contains formate ions, and the content thereof is 300 to 6000 mass ppm. The lower limit of the content of formate ions is preferably 300 mass ppm or more, for example, from the viewpoint of suppressing the increase in defects, but may be 400 mass ppm or more, or may be 350 mass ppm or more. Also, the upper limit of this content is preferably 6000 mass ppm or less, for example, from the viewpoint of stability over time, but may be 5900 mass ppm or less, or may be 5950 mass ppm or less. The above-mentioned increase in defects can contribute to the deterioration of electrical characteristics, and the ability to suppress the increase in defects is also preferable in that it can effectively suppress such deterioration of electrical characteristics. The method for controlling the content of formate ions is not particularly limited, but for example, a method of adding formic acid, its salts, and other derivatives may be used.

[0050] (Additives, etc.)

[0051] The dicing protective film composition according to this embodiment may contain other known additives as necessary. Examples of other additives include basic compounds, dyes, pigments, plasticizers, preservatives, surfactants, and various other additives.

[0052] (Basic compound)

[0053] The dicing protective film composition according to this embodiment may contain a basic compound for the purpose of making the solid content more easily soluble. As the basic compound, either an inorganic compound or an organic compound can be used.

[0054] Specific examples of the basic compound include, for example, sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium silicate, sodium metasilicate, ammonia, ethylamine, n-propylamine, monoethanolamine, diethylamine, di-n-propylamine, diethanolamine, triethylamine, methyldiethylamine, dimethylethanolamine, triethanolamine, tetramethylammonium hydroxide, tetraethylammonium hydroxide, pyrrole, piperidine, 1,8-diazabicyclo[5,4,0]-7-undecene, 1,5-diazabicyclo[4,3,0]-5-nonane, and the like.

[0055] (Dye)

[0056] The dye is preferably a water-soluble dye. Specific examples of the water-soluble dye include, for example, azo dyes (monoazo and polyazo dyes, metal complex azo dyes, pyrazolone azo dyes, stilbene azo dyes, thiazole azo dyes), anthraquinone dyes (anthraquinone derivatives, anthrone derivatives), indigoid dyes (indigoid derivatives, thioindigoid derivatives), phthalocyanine dyes, carbonium dyes (diphenylmethane dyes, triphenylmethane dyes, xanthene dyes, acridine dyes), quinoneimine dyes (azine dyes, oxazine dyes, thiazine dyes), methine dyes (cyanine dyes, azomethine dyes), quinoline dyes, nitroso dyes, benzoquinone dyes, naphthoquinone dyes, naphthalimide dyes, perinone dyes, and other dyes.

[0057] (Pigment)

[0058] As the pigment, it is preferably a water-soluble pigment. Specific examples of the water-soluble pigment include, for example, Food Red No. 2, Food Red No. 40, Food Red No. 102, Food Red No. 104, Food Red No. 105, Food Red No. 106, Food Yellow NY, Food Yellow No. 4 Tartrazine, Food Yellow No. 5, Food Yellow No. 5 Sunset Yellow FCF, Food Orange Color AM, Food Red No. 1, Food Red No. 4, Food Red No. 101, Food Blue No. 1, Food Blue No. 2, Food Green No. 3, Food Melon Color B, Food Egg Color No. 3 and other food additive pigments. The food additive pigments are suitable from the viewpoint of low environmental impact and the like.

[0059] (Plasticizer)

[0060] By using a plasticizer, the generation of cracks in the protective film can be more effectively suppressed, and the flexibility, elasticity, laser processability, etc. of the protective film can be more effectively improved. Specific examples of the plasticizer include, for example, monosaccharides, disaccharides, and the like.

[0061] (Preservative)

[0062] From the viewpoint of further improving the antiseptic effect of the dicing protective film composition according to the present embodiment and further reducing the treatment load of the waste liquid after semiconductor wafer cleaning, it is preferable to use a preservative.

[0063] (Surfactant)

[0064] The surfactant is used, for example, to enhance the defoaming property during the production of the dicing protective film composition, the stability of the dicing protective film composition, and the coatability of the dicing protective film composition. From the viewpoint of defoaming property during the production of the dicing protective film composition, a surfactant may be used. As the surfactant, a water-soluble surfactant can be preferably used. Examples of the surfactant include nonionic surfactants, cationic surfactants, anionic surfactants, amphoteric surfactants, and the like.

[0065] The protective film is formed, for example, by spin-coating a dicing protective film composition. However, unevenness may occur due to air bubbles when forming the protective film. In order to suppress the occurrence of such unevenness, an antifoaming agent such as a surfactant can be used.

[0066] (Water, organic solvent)

[0067] The dicing protective film composition according to the present embodiment contains water from the viewpoints of dissolving the above-described solid components and removing the dicing protective film by water washing. As the water, pure water, ultrapure water (DIW), ion water, distilled water, purified water, etc. can be used.

[0068] And the dicing protective film composition according to the present embodiment preferably further contains an aqueous organic solvent as necessary. More preferably, the solvent is a mixed solvent containing water and an aqueous organic solvent.

[0069] The aqueous organic solvent is not particularly limited, but is preferably at least one selected from the group consisting of glycol solvents, alcohol solvents, ketone solvents, lactone solvents, ester solvents, sulfonic acid solvents, amide solvents, and pyrrolidone solvents, and more preferably at least one selected from the group consisting of glycol solvents and alcohol solvents.

[0070] Examples of the glycol solvent include glycols, glycol ether solvents, glycol ester solvents, etc.

[0071] Specific examples of the glycols include ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, glycerin, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, furfuryl alcohol, hexylene glycol, etc.

[0072] Specific examples of glycol ether solvents include alkylene glycol monoalkyl ethers, alkylene glycol dialkyl ethers, high molecular type polyalkylene glycol ether solvents, and the like.

[0073] Examples of alkylene glycol monoalkyl ethers include ethylene glycol monomethyl ether, diethylene glycol monomethyl ether, triethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monobutyl ether, triethylene glycol monobutyl ether, ethylene glycol monohexyl ether, diethylene glycol monohexyl ether and other ethylene-based glycol monoalkyl ethers; propylene glycol monomethyl ether (PGME), propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, dipropylene glycol monomethyl ether (DPM), dipropylene glycol monoethyl ether, dipropylene glycol monopropyl ether, dipropylene glycol monobutyl ether, tripropylene glycol monomethyl ether, tripropylene glycol monoethyl ether, tripropylene glycol monobutyl ether and other propylene-based glycol monoalkyl ethers, and the like.

[0074] Examples of the alkylene glycol dialkyl ethers include ethylene glycol dialkyl ethers such as ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, diethylene glycol dibutyl ether, triethylene glycol dibutyl ether, ethylene glycol dihexyl ether, and diethylene glycol dihexyl ether; propylene glycol dialkyl ethers such as propylene glycol dimethyl ether, propylene glycol diethyl ether, propylene glycol dipropyl ether, propylene glycol dibutyl ether, dipropylene glycol dimethyl ether, dipropylene glycol diethyl ether, dipropylene glycol dipropyl ether, dipropylene glycol dibutyl ether, tripropylene glycol dimethyl ether, tripropylene glycol diethyl ether, and tripropylene glycol dibutyl ether.

[0075] Examples of the polyalkylene glycol ethers include polyalkylene glycol ethers such as polyoxypropylene butyl ether, polyoxyethylene polyoxypropylene butyl ether, polyoxyethylene oleyl ether, and polyoxyethylene polyoxypropylene-2-ethylhexyl ether.

[0076] Among these, ethylene glycol monoalkyl ethers, propylene glycol monoalkyl ethers, ethylene glycol dialkyl ethers, propylene glycol dialkyl ethers, etc. are preferable, and propylene glycol monomethyl ether (PGME) etc. are more preferable.

[0077] Specific examples of the glycol ester solvents include alkylene glycol monoalkyl ether acetates etc.

[0078] Examples of alkylene glycol monoalkyl ether acetates include ethylene glycol ether acetates such as ethylene glycol monobutyl ether acetate and diethylene glycol monobutyl ether acetate; propylene glycol ether acetates such as propylene glycol monomethyl ether acetate (PGMEA), dipropylene glycol monomethyl ether acetate, and propylene glycol diacetate, etc.

[0079] Among these, ethylene glycol ether acetates and propylene glycol ether acetates are preferred, and propylene glycol monomethyl ether acetate (PGMEA) etc. are more preferred.

[0080] Specific examples of alcohol solvents include, for example, aliphatic alcohols such as methanol, ethanol, denatured ethanol, isopropanol, n-propanol, n-butanol, 3-methoxy-3-methyl-1-butanol, etc.

[0081] Specific examples of ketone solvents include acetone, methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), diisobutyl ketone, cyclohexanone, cyclopentanone, diacetone alcohol, 1-hexanone, 2-hexanone, 4-heptanone, 2-heptanone, 1-octanone, 2-octanone, 1-nonanone, 2-nonanone, acetylacetone, acetonylacetone, phenylacetone, acetophenone, methylnaphthyl ketone, methylcyclohexanone, ionone, isophorone, propylene carbonate (propylene carbonate), diacetonyl alcohol, acetyl carbinol, etc.

[0082] Specific examples of lactone solvents include γ-butyrolactone, α-methyl-γ-butyrolactone, β-propiolactone, γ-valerolactone, δ-valerolactone, γ-caprolactone, ε-caprolactone, γ-laurolactone, hexanolactone, etc.

[0083] Specific examples of the ester solvents include methyl acetate, ethyl acetate, butyl acetate, amyl acetate, propyl acetate, isopropyl acetate, methyl lactate, ethyl lactate, butyl lactate, ethyl methoxyacetate, ethyl ethoxyacetate, 2-methoxybutyl acetate (2-methoxybutyl acetate), 3-methoxybutyl acetate (3-methoxybutyl acetate), 4-methoxybutyl acetate (4-methoxybutyl acetate), 3-methoxy-3-methylbutyl acetate (3-methoxy-3-methylbutyl acetate), 3-ethyl-3-methoxybutyl acetate (3-ethyl-3-methoxybutyl acetate), 4-methyl-4-methoxypentyl acetate, ethyl lactate, propyl lactate, butyl lactate, and the like.

[0084] Specific examples of the sulfonic acid solvents include, for example, dimethyl sulfone, diethyl sulfone, tetramethylene sulfone, dipropyl sulfone, sulfolane (also known as tetramethylene sulfone), 3-methyl sulfolane, 2,4-dimethyl sulfolane, 3,4-dimethyl sulfolane, diphenyl sulfolane, 3,4-diphenylmethyl sulfolane, sulfolene, 3-methyl sulfolene, 3-ethyl sulfolene, and the like.

[0085] Specific examples of the amide solvents include, for example, N,N-dimethylformamide (DMF), diethylformamide (DEF), N,N-dimethylacetamide (DMAc), N-methylpyrrolidine (MPD), hexamethylphosphoric triamide (HMPA), and the like.

[0086] Specific examples of the pyrrolidone solvents include, for example, N-methylpyrrolidone (NMP), 2-pyrrolidone, N-vinyl-2-pyrrolidone, and the like.

[0087] The dicing protective film composition according to this embodiment may contain one kind of the above-mentioned aqueous organic solvent, or may contain two or more kinds, but it is preferable to contain two or more kinds of aqueous organic solvents. As a preferred example in the case of containing two or more kinds of aqueous organic solvents, two or more kinds of the above-mentioned organic solvents can be selected.

[0088] As an example of the combination in the mixed solvent of water and a water-based organic solvent, it is preferably a mixed solvent containing water and at least one selected from the group consisting of glycol solvents and alcohol solvents; more preferably, it is a mixed solvent containing water and at least one selected from the group consisting of glycol ether solvents, glycol ester solvents, and alcohol solvents; still more preferably, it is a mixed solvent containing water and at least one selected from the group consisting of propylene glycol monomethyl ether (PGME), methanol, ethanol, denatured ethanol, isopropanol, n-propanol, n-butanol, and 3-methoxy-3-methyl-1-butanol; even more preferably, it is a mixed solvent containing water and propylene glycol monomethyl ether (PGME).

[0089] The mixing ratio of water and the water-based organic solvent in the mixed solvent is not particularly limited, but the water content in 100 parts by mass of the total amount of water and the water-based organic solvent is preferably 30 to 99 parts by mass. The lower limit of this water content is more preferably 40 parts by mass or more, still more preferably 50 parts by mass or more, even more preferably 60 parts by mass or more, and still even more preferably 70 parts by mass or more. Also, the upper limit of this water content is more preferably 95 parts by mass or less, and still more preferably 90 parts by mass or less.

[0090] (Solid content concentration)

[0091] The solid content concentration in the dicing protective film composition according to this embodiment is not particularly limited, but is preferably 1 to 90% by mass. The lower limit of the solid content concentration is more preferably 5% by mass or more, and still more preferably 10% by mass or more. Further, the upper limit of the solid content concentration is more preferably 80% by mass or less, still more preferably 60% by mass or less, even more preferably 40% by mass or less, and even more preferably 30% by mass or less. In the measurement of the solid content concentration, the components excluding the solvent (water, organic solvent, etc.) from the total amount of the dicing protective film composition are defined as the "solid content". And the "solid content concentration" is the ratio of the total amount of the components other than the solvent contained in the dicing protective film composition to the total amount of the dicing protective film composition (total amount of the components other than the solvent contained in the dicing protective film composition / total amount of the dicing protective film composition (% by mass)).

[0092] <Wafer manufacturing method, processing method>

[0093] According to this embodiment, after applying the above-described dicing protective film composition onto a substrate or the like to be protected to form a protective film (dicing protective film), dicing is performed, whereby a wafer can be manufactured. As such a wafer manufacturing method, it is preferable that it is a wafer manufacturing method including a film forming step of applying the above-described dicing protective film composition onto the processing surface of the wafer to form a protective film, and a processing step of irradiating the processing surface with laser light through the protective film to perform processing. Further, it is more preferable to include a step of removing the protective film by water washing after the processing step.

[0094] And according to this embodiment, it is also suitable as a wafer processing method using the above-described dicing protective film composition. As such a wafer processing method, it is preferable that it is a wafer processing method including a film forming step of applying the above-described dicing protective film composition to form a protective film, and a processing step of irradiating the processing surface with laser light through the protective film to perform processing.

[0095] The method of coating in the film formation process is not particularly limited, but depending on the shape and material of the substrate, etc., spin coating, spray coating, die coating, roll coating, flow coating, curtain coating, etc. can be adopted, but it is preferable to coat by spin coating. Further, after coating, post-treatments such as a drying process such as natural drying or hot air drying, and a light irradiation process such as ultraviolet irradiation may be performed.

[0096] When coating by spin coating, for example, (a) a step of applying a dicing protective film composition to an object to be coated (such as a semiconductor wafer) fixed on the stage of a spin coater (discharge step), (b) by rotating the stage, removing the excess dicing protective film composition by centrifugal force to form a thin film (rotation treatment step), (c) removing the workpiece from the spin coater and performing a step of producing a thin film (drying step) by natural drying, hot air drying, etc. Spin coating is suitable because it has advantages such as being able to form a film with little film thickness deviation and being implementable even without a vacuum, so it is excellent in film formation cost and film formation speed.

[0097] The film thickness of the protective film is not particularly limited, but usually, it is preferably 0.1 to 100 μm in order to facilitate the removal of the protective film by water washing after processing and to ensure the durability of the protective film against the irradiation of the laser light described later. The lower limit of the film thickness is more preferably 1 μm or more, and even more preferably 3 μm or more. Also, the upper limit of the film thickness is more preferably 50 μm or less, even more preferably 30 μm or less, still more preferably 20 μm or less, and even more preferably 10 μm or less. In this regard, for example, when forming a protective film by spin coating, it is possible to more effectively perform film formation with excellent film formability and selectivity ratio for the film thickness within the above range.

[0098] In the processing step, it is preferable to perform laser dicing in which a laser beam is irradiated onto the processed surface. Since laser dicing can perform processing without contacting the wafer to be processed, defects such as cracks and chipping can be effectively suppressed. Specifically, a plurality of semiconductor chips partitioned by lattice-shaped streets are formed on the wafer, and it is more preferable that the processing step is a step of forming grooves by irradiating the streets with a laser beam through a protective film. These grooves become processing grooves having a pattern according to the shape of the semiconductor chips.

[0099] According to the dicing protective film composition and the protective film according to this embodiment, it is expected to improve the film-forming property, the straightness of the processing groove (the straightness of the side wall of the protective film constituting the processing groove), and the rectangularity of the cross section of the processing groove (the rectangularity of the cross section of the protective film constituting the processing groove). When the processability is excellent, it is possible to perform accurate processing without deviating from the desired position, so that it is also possible to perform processing with higher positional accuracy.

[0100] Note that, from the viewpoint of intensity, the laser beam is preferably an ultraviolet laser having a wavelength of 100 to 400 nm. Also, it is preferably a YVO4 laser or a YAG laser having a wavelength of 266 nm, 355 nm, etc.

[0101] The above laser beam irradiation in the processing groove forming step can be performed, for example, under the following processing conditions. Note that the condensing spot diameter can be appropriately selected in consideration of the width of the processing groove. Light source of laser beam: YVO4 laser or YAG laser Wavelength: 355 nm Repetition frequency: 50 to 100 kHz Output: 0.1 to 4.0 W Processing feed rate: 1 to 800 mm / second

[0102] After irradiating laser light along a predetermined street, the semiconductor wafer held on the chuck table is indexed and moved by the interval of the streets, and the laser light can be irradiated again. In this way, after performing the irradiation and indexing movement of the laser light for all the streets extending in a predetermined direction, the semiconductor wafer held on the chuck table is rotated by 90 degrees. Then, along each street extending at a right angle to the predetermined direction, the irradiation and indexing movement of the laser light are executed in the same manner as above. In this way, a processing groove can be formed along the streets formed in the laminate on the semiconductor wafer.

[0103] Furthermore, it may be carried out up to a cutting step of cutting the position of the processing groove provided on the processing surface of the wafer (the position corresponding to the position of the street). When carried out up to the cutting step, it is suitable for the method of manufacturing a semiconductor chip.

[0104] After performing the dicing step, the protective film covering the surface of the semiconductor chip is removed. Since the dicing protective film composition according to the present embodiment contains a water-soluble resin, the protective film can be efficiently washed away with water.

[0105] As described above, an example of the method for manufacturing and processing a semiconductor wafer has been described. According to the above method according to the present embodiment, by using the protective film formed by the dicing protective film composition according to the present embodiment, debris can be effectively washed away by washing after dicing. It is particularly suitable when washing with water. The dicing protective film composition according to the present embodiment contains a predetermined ultraviolet absorber and a water-soluble resin, and controls the content of formate ions to a predetermined ratio, so that the protective film formed on the wafer can be effectively prevented from peeling or being damaged. And it can suppress the decrease in absorbance over time, and can also suppress the increase in the number of defects over time. Therefore, it can effectively prevent the protective film from peeling off unintentionally during laser processing.

Example

[0106] The present invention will be described in more detail by the following examples and comparative examples, but the present invention is not limited to the following examples in any way. Unless otherwise specified below, the quantity is based on mass, and the experiments were carried out under the conditions of 25°C and atmospheric pressure.

[0107] <Component>

[0108] A list of the components used in the examples and comparative examples is shown. ·PVA: Polyvinyl alcohol (saponification degree 75%, manufactured by Kuraray Co., Ltd., "Poval (registered trademark) PVA5-74LLA") ·PVP: Polyvinylpyrrolidone (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., "PVP K90") ·Ferulic acid ·Water: DIW (ultrapure water) ·PGME: Propylene glycol monomethyl ether ·Formate ion: Formic acid was added to obtain a predetermined formate ion concentration.

[0109] <Preparation of dicing protective film composition>

[0110] Each component was mixed to obtain each composition shown in Table 1, and a dicing protective film composition (hereinafter sometimes referred to as "chemical solution") was prepared. The solid content concentration in Table 1 refers to the concentration of the components excluding the solvent among the components contained in the obtained chemical solution. For example, Example 1 is a liquid dicing protective film composition dissolved in a mixed solvent with a mixing ratio of water and PGME (water / PGME) of 80:20 by mass so as to contain 100 parts by mass of PVA and 5 parts by mass of ferulic acid and have a solid content concentration of 20% by mass, and the content of formate ion was 6000 ppm by mass. Also, for example, Example 13 is a liquid dicing protective film composition dissolved in a mixed solvent with a mixing ratio of water and PGME (water / PGME) of 80:20 by mass so as to contain 100 parts by mass of a resin with a mixing ratio of PVA and PVP (PVA / PVP) of 50:50 by mass and 5 parts by mass of ferulic acid and have a solid content concentration of 15% by mass, and the content of formate ion was 2000 ppm by mass.

[0111] (Measurement of Solid Content Concentration)

[0112] The solid content concentration was defined as the total amount of components other than the solvent contained in the "chemical solution" / the total amount of the "chemical solution" (mass%).

[0113] (Measurement of Formate Ions)

[0114] The formate ions in the dicing protective film composition were quantified by ion chromatography.

[0115] <Evaluation of Absorbance>[[]]END]]

[0116] The chemical solutions of each example and each comparative example were stored in a polyethylene tank for a predetermined period (initial, 2 weeks, 1 month) at 40 °C in a light-shielded environment. Then, the absorbance was measured using an ultraviolet-visible spectrophotometer (UV-vis), and the gram absorption coefficient (unit: L / g·cm) was adopted.

[0117] <Evaluation of Defect Number>[[]]END]]

[0118] First, the chemical solutions of each example and each comparative example were applied to the surface of a silicon substrate (12-inch Si substrate) using a spinner under the conditions of 2000 rpm for 120 seconds. Then, it was naturally dried at room temperature for 10 minutes to form a protective film with a thickness of 1 μm.

[0119] Subsequently, the protective film was rinsed with pure water for 300 seconds and then dried.

[0120] Using a wafer defect inspection apparatus (manufactured by KLA-Tencor, "Surfscan SP5"), the number of foreign matters with a maximum major axis greater than 300 nm was counted as the number of defects. The measurements were taken immediately after preparing the chemical solution ("initial"), one week after preparing the chemical solution ("1W"), and one month after preparing the chemical solution ("1M"), respectively. Then, taking the number of defects in the "initial" (immediately after preparation) of Example 1 as the reference value "1", the number of defects in each example and each comparative example was determined as the relative ratio to this. If the value of "1M" (one month after) could be suppressed to 3 times or less the value of "initial" of Example 1, it was judged as "〇" (qualified) assuming that characteristics sufficient for practical use could be expected from the viewpoint of electrical characteristics and the like.

[0121] For example, in the case of Example 2, the number of defects in the "initial" was 1.1 times that of the "initial" of Example 1, the number of defects in "2W" (two weeks after) was 1.2 times that of the "initial" of Example 1, and the number of defects in "1M" (one month after) was 1.3 times that of the "initial" of Example 1, indicating that it was "〇" (qualified).

[0122] For example, in the case of Comparative Example 1, the number of defects in the "initial" was 1.3 times that of the "initial" of Example 1, the number of defects in "2W" (two weeks after) was 2.2 times that of the "initial" of Example 1, and the number of defects in "1M" (one month after) was 3.2 times that of the "initial" of Example 1, indicating that it was "×" (unqualified).

[0123] The compositions of each example and each comparative example are shown in Table 1, and the evaluation results of each example and each comparative example are shown in Table 2.

[0124]

Table 1

[0125]

Table 2

[0126] From the above, it was at least confirmed that the dicing protective film composition according to this example can suppress the decrease in absorbance over time and can suppress the increase in the number of defects over time.

Claims

1. An ultraviolet absorber containing a compound (1) represented by the following general formula (1), a water-soluble resin, formate ions, and water, wherein the content of the formate ions is 300 to 6000 ppm by mass, A protective film composition for dicing. 【Chemical 1】 (In the formula, X represents a hydrogen atom, -OR １ represents. R １ represents a substituted or unsubstituted alkyl group having 1 to 5 carbon atoms. n represents a number from 1 to 5, and m represents a number from 0 to 4.)

2. The ultraviolet absorber is at least one selected from the group consisting of ferulic acid, 2-hydroxybenzoic acid, 4-hydroxybenzoic acid, 2,3-dihydroxybenzoic acid, and 3,4-dihydroxybenzoic acid, The protective film composition for dicing according to Claim 1.

3. The water-soluble resin is at least one resin selected from the group consisting of a resin (2a) containing a structural unit represented by the following formula (2a-1) and a structural unit represented by the following formula (2a-2), and a resin (2b) containing a structural unit represented by the following formula (2b), The protective film composition for dicing according to Claim 1 or 2. 【Chemical 2】

4. Furthermore, it contains an aqueous organic solvent, The protective film composition for dicing according to Claim 1 or 2.

5. The aqueous organic solvent is at least one selected from the group consisting of a glycol-based solvent and an alcohol-based solvent, The protective film composition for dicing according to Claim 4.

6. As the aqueous organic solvent, it contains two or more kinds of aqueous organic solvents, The protective film composition for dicing according to Claim 5.

7. The solid content concentration is 1 to 90% by mass, The protective film composition for dicing according to Claim 1 or 2.

8. A film-forming step of applying the protective film composition for dicing according to Claim 1 or 2 to the processed surface of a wafer to form a protective film, and A processing step of irradiating the processed surface with laser light through the protective film to perform processing A method for manufacturing a wafer, including.

9. A plurality of semiconductor chips partitioned by grid-like streets are formed on the wafer, The processing step is a step of forming grooves by irradiating the streets with laser light through the protective film, The method for manufacturing a wafer according to Claim 8.

10. After the processing step, it includes a step of removing the protective film by washing with water, The method for manufacturing a wafer according to Claim 8.

11. A film-forming step of applying the protective film composition for dicing according to Claim 1 or 2 to the processed surface of a wafer to form a protective film, and A processing step of irradiating the processed surface with laser light through the protective film to perform processing A method for processing a wafer, including.

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