TW202313872A - Method for forming protective film, method for manufacturing semiconductor chip, and method for preparing coating liquid capable of forming a protective film on a surface of a semiconductor wafer during dicing of the semiconductor wafer - Google Patents

Abstract

The present invention provides: a method for forming a protective film, which forms a protective film on a surface of a semiconductor wafer during dicing of the semiconductor wafer, and can suppress foreign matter in the formed protective film even after manufacturing a protective film forming agent; a method for manufacturing a semiconductor chip using the method for forming a protective film; and a method for preparing a coating liquid that can be used in the method for forming the protective film. The method for forming a protective film of the present invention is to form a protective film on the surface of a semiconductor wafer during dicing of the semiconductor wafer, and includes: a step of preparing a protective film forming agent, which prepares the following protective film forming agent, wherein the aforementioned protective film forming agent includes a water-soluble resin (A), a light absorbing agent (B) and a solvent (S), the solvent (S) contains water, and a solid content concentration of the aforementioned protective film forming agent is 20% by mass or more; a coating liquid preparation step, which is configured to dilute the protective film forming agent to prepare a coating liquid; and a protective film forming step for applying the coating liquid on a semiconductor wafer to form a protective film.

Description

Method for forming protective film, method for manufacturing semiconductor wafer, and method for preparing coating liquid

The present invention relates to a method for forming a protective film for forming a protective film on the surface of a semiconductor wafer during dicing of a semiconductor wafer, a method for manufacturing a semiconductor wafer using the method for forming a protective film, and a method that can be used for the above-mentioned protective film. The preparation method of the coating liquid of the formation method.

The wafer formed in the semiconductor device manufacturing process is obtained by dividing the laminated body in which the insulating film and the functional film are layered on the surface of the semiconductor substrate such as silicon according to the grid-shaped predetermined dividing line called a street. Each area divided by the track becomes a semiconductor chip such as IC or LSI.

By cutting the wafer along the track, a plurality of semiconductor wafers can be obtained. Also, in an optical device wafer, a laminate in which gallium nitride-based compound semiconductors and the like are laminated is divided into a plurality of regions by tracks. By cutting along the tracks, the optical device wafer is divided into optical devices such as light emitting diodes and laser diodes. Such optical devices are widely used in electrical equipment.

In the past, such cutting of the wafer along the track was performed using a cutting device called a dicer. However, in this method, since the wafer having a laminated structure is a highly brittle material, there is a problem that damage, chipping, etc. Or the insulating film required as a circuit element formed on the surface of the wafer is peeled off.

In order to solve this problem, the following method has been proposed: forming a mask containing a layer of water-soluble material on the surface of the semiconductor substrate, and then irradiating laser light on the mask to decompose and remove a part of the mask, thereby forming a layer on the mask. A part of the surface of the semiconductor substrate is exposed, and then, the semiconductor substrate exposed from a part of the mask is cut by plasma etching, and the semiconductor substrate is divided into semiconductor chips (IC) (see Patent Document 1).

A mask (protective film) of a layer containing a water-soluble material is formed, for example, by applying a protective film-forming agent containing a water-soluble resin on a semiconductor substrate. [Prior Art Literature] [Patent Document]

[Patent Document]: Japanese Patent Application Publication No. 2014-523112

[Problem to be solved by the invention]

When a protective film forming agent is applied on the surface of a semiconductor substrate to form a protective film as a mask, there are cases where the protective film forming agent is stored or transported after production rather than immediately after the production of the protective film forming agent. , coating the protective film forming agent on the semiconductor substrate. If the protective film forming agent is applied to the semiconductor substrate after a lapse of time after the protective film forming agent is produced in this way, there is the following problem: compared with the case where the protective film forming agent is applied to the semiconductor substrate immediately after the production of the protective film forming agent Foreign matter generated by the protective film increases.

The present invention has been made in view of the above problems, and its object is to provide a protective film forming method that forms a protective film on the surface of a semiconductor wafer during dicing of the semiconductor wafer, even after time elapses after the protective film forming agent is produced. , which can also suppress the increase of foreign matter in the formed protective film; a method for manufacturing a semiconductor wafer using the method for forming the protective film; and a method for preparing a coating liquid that can be used for the above-mentioned method for forming the protective film. [Technical means to solve the problem]

The inventors of the present invention have found that the above-mentioned problems can be solved by preparing a specific protective film forming agent, diluting the protective film forming agent to prepare a coating liquid, and applying the coating liquid on a semiconductor wafer to form a protective film. The present invention has thus been accomplished. More specifically, the present invention provides the following.

The first aspect of the present invention is a method for forming a protective film, which is to form a protective film on the surface of a semiconductor wafer during dicing of the semiconductor wafer, which has: A protective film forming agent preparation step, which prepares a protective film forming agent comprising a water-soluble resin (A), a light absorbing agent (B) and a solvent (S), the solvent (S) comprising water, and the above The solid content concentration of the protective film forming agent is 20% by mass or more; a coating solution preparation step of diluting the protective film forming agent to prepare a coating solution; and The protective film forming step is to apply the above-mentioned coating solution on the semiconductor wafer to form a protective film.

The second aspect of the present invention is a method of manufacturing a semiconductor wafer, which is for processing a semiconductor wafer, and has: a protective film forming step of forming a protective film on the above-mentioned semiconductor wafer by using the protective film forming method of the first aspect; A processing groove forming step of irradiating laser light to predetermined positions of one or more layers of the above-mentioned protective film on the above-mentioned semiconductor wafer to form a pattern corresponding to the shape of the semiconductor wafer with the surface of the above-mentioned semiconductor wafer exposed slot; and A cutting step, which cuts off the positions of the processing grooves in the semiconductor wafer.

A third aspect of the present invention is a preparation method of a coating liquid for forming a protective film on the surface of a semiconductor wafer during dicing of the semiconductor wafer, The above preparation method has a dilution step of diluting the protective film forming agent comprising water-soluble resin (A), light absorbing agent (B) and solvent (S), wherein the solvent (S) comprises water, And the solid content concentration of the said protective film forming agent is 20 mass % or more. [Effect of Invention]

According to the present invention, it is possible to provide a method for forming a protective film which can suppress the formation of a protective film on the surface of a semiconductor wafer during dicing of the semiconductor wafer even after time passes after the protective film forming agent is produced. The increase of foreign matter in the protective film; a method of manufacturing a semiconductor wafer using the method of forming the protective film; and a method of preparing a coating liquid that can be used in the method of forming the protective film.

≪Protection film formation method and coating solution preparation method≫ The method for forming a protective film is a method for forming a protective film for forming a protective film on the surface of a semiconductor wafer during dicing of the semiconductor wafer. Specifically, the method of forming a protective film is favorably used in the step of forming a protective film in a method of manufacturing a semiconductor wafer including: a protective film forming step of forming a protective film on the semiconductor wafer; A processing groove forming step of irradiating laser light to a predetermined position of one or more layers including a protective film on the semiconductor wafer to form a processing groove having a pattern corresponding to the shape of the semiconductor wafer that is exposed on the surface of the semiconductor wafer; and A cutting step, which cuts off the position of the processing groove in the semiconductor wafer.

The method of forming a protective film has: a protective film forming agent preparation step, which prepares the following protective film forming agent, the above-mentioned protective film forming agent includes a water-soluble resin (A), a light absorbing agent (B) and a solvent (S), and the solvent (S ) contains water, and the above-mentioned protective film forming agent has a solid content concentration of 20% by mass or more; a coating liquid preparation step of diluting the protective film forming agent to prepare a coating liquid; and a protective film forming step of applying the coating liquid A protective film is formed on the semiconductor wafer.

＜Preparation procedure of protective film forming agent＞ In the protective film forming agent preparation step, a protective film forming agent is prepared. Protective Film Forming Agent The protective film forming agent prepared in the preparation step contains a water-soluble resin (A), a light absorbing agent (B), and a solvent (S), and the solvent (S) contains water. Moreover, the solid content concentration of a protective film forming agent is 20 mass % or more. Hereinafter, the essential components or optional components contained in a protective film forming agent, and solid content concentration are demonstrated.

＜Water-soluble resin (A)＞ The water-soluble resin (A) is a base material of a protective film formed using a protective film forming agent. The type of the water-soluble resin (A) is not particularly limited as long as it can be dissolved in a solvent such as water, applied and dried to form a film. The term "water-soluble" refers to a solute (water-soluble resin) that dissolves 0.5 g or more in 100 g of water at 25°C.

From the standpoint of both decomposability and film-forming properties when irradiated with laser light, the weight average molecular weight of the water-soluble resin (A) is preferably from 15,000 to 300,000, more preferably from 20,000 to 200,000.

Specific examples of the type of water-soluble resin (A) include vinyl resins, cellulose resins, polyethylene oxide, polyglycerin, and water-soluble nylon. The vinyl resin is not particularly limited as long as it is a homopolymer or copolymer of a monomer having a vinyl group and is water-soluble. Examples of vinyl resins include polyvinyl alcohol, polyvinyl acetal (including vinyl acetate copolymers), polyvinylpyrrolidone, polyacrylamide, poly(N-alkylacrylamide), polyvinyl Allylamine, poly(N-alkylallylamine), partially amidated polyallylamine, poly(diallylamine), allylamine-diallylamine copolymer, polyacrylic acid, polyvinyl alcohol polyacrylic acid block copolymer substances, and polyvinyl alcohol polyacrylate block copolymers. The cellulose-based resin is not particularly limited as long as it is a water-soluble cellulose derivative. The cellulose-based resin may, for example, be methyl cellulose, ethyl cellulose or hydroxypropyl cellulose. Furthermore, the water-soluble resin (A) preferably does not have an acidic group. These can be used individually by 1 type, and can also use them in combination of 2 or more types.

Among the specific examples of the above-mentioned water-soluble resin (A), vinyl-based resins and cellulose-based resins are preferred, more preferably polyvinylpyrrolidone, and hydroxypropyl cellulose.

The protective film formed on the surface of the semiconductor wafer is usually formed from the semiconductor wafer or the surface of the semiconductor wafer at an appropriate time point after forming the processing groove corresponding to the method of processing the semiconductor wafer with the protective film and the processing groove into a semiconductor wafer. remove. Therefore, from the viewpoint of water washability of the protective film, a water-soluble resin having low affinity with the surface of the semiconductor wafer is preferable. As the water-soluble resin having low affinity with the semiconductor wafer surface, resins having only ether bonds, hydroxyl groups, and amide bonds as polar groups are preferable, such as polyvinyl alcohol, polyethylene glycol, polyvinylpyrrolidone, and hydroxypropyl cellulose.

The water-soluble resin (A) in the protective film forming agent is considered to be less likely to cause poor opening when the protective film is irradiated with laser light to form the processing groove, or the shape of the processing groove is deteriorated due to heat sinking of the protective film. The mass ratio to the total mass of the water-soluble resin (A) and the light absorbing agent (B) is preferably from 60 mass % to 99 mass %, more preferably from 85 mass % to 98 mass %.

＜Absorbent (B)＞ As a light absorbing agent (B), the light absorbing agent normally used for a protective film forming agent can be used. As the light-absorbing agent (B), it is preferable to use a water-soluble light-absorbing agent such as a water-soluble dye, a water-soluble pigment, or a water-soluble ultraviolet absorber. The water-soluble light absorbing agent is advantageous in that it exists uniformly in a protective film. As the water-soluble light-absorbing agent, organic acids having carboxyl or sulfo groups; sodium salts, potassium salts, ammonium salts, and quaternary ammonium salts of organic acids; compounds having hydroxyl groups may be mentioned. When a water-soluble light-absorbing agent is used, the preservation stability of the protective film-forming agent is high, and it is possible to suppress undesirable phenomena such as phase separation of the protective film-forming agent or precipitation of the light-absorbing agent during storage of the protective film-forming agent. It is also advantageous to maintain good applicability of the protective film forming agent over a long period of time.

Furthermore, water-insoluble light-absorbing agents such as pigments can also be used. When using a water-insoluble light-absorbing agent, although there is no fatal hindrance to the use of the protective film forming agent, there are some cases where the laser absorption ability of the protective film varies or it is difficult to obtain storage stability. Either it is a protective film forming agent with excellent applicability, or it is difficult to form a protective film with a uniform thickness.

(式(B1)中，R ¹及R ³各自獨立地為羥基或羧基，R ²及R ⁴各自獨立地為羥基、羧基、或-NR ⁵R ⁶表示之基，R ⁵及R ⁶各自獨立地為氫原子、或碳原子數1以上4以下之烷基，m及n各自獨立地為0以上2以下之整數。) The light absorbing agent (B) may, for example, be a benzophenone-based compound, a cinnamic acid-based compound, an anthraquinone-based compound, a naphthalene-based compound, or a biphenyl-based compound. As a benzophenone type compound, the compound represented by following formula (B1) is mentioned. The compound represented by the following formula (B1) is preferable because it enables the protective film to efficiently absorb the energy of laser light and promotes thermal decomposition of the protective film. [chemical 1]

(In formula (B1), R ¹ and R ³ are each independently hydroxyl or carboxyl, R ² and R ⁴ are each independently hydroxyl, carboxyl, or a group represented by -NR ⁵ R ⁶ , R ⁵ and R ⁶ are independently ground is a hydrogen atom, or an alkyl group with 1 to 4 carbon atoms, and m and n are each independently an integer of 0 to 2.)

The compound represented by the above-mentioned formula (B1) has a high light absorption coefficient, and even when it is added to the protective film forming agent together with a base, it shows a high light absorption coefficient. Therefore, if a protective film is formed using a protective film forming agent containing a compound represented by the above-mentioned formula (B1) as a light absorbing agent (B), when a mask for dicing is formed, the protective film can be partially shielded from lightning. Decomposition caused by radiation.

In the above formula (B1), R ² and R ⁴ may be a group represented by -NR ⁵ R ⁶ . R ⁵ and R ⁶ are each independently a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. The alkyl groups as R ⁵ and R ⁶ may be linear or branched. Specific examples of the alkyl groups for R ^{and R} are methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, second-butyl, and third-butyl.

The group represented by -NR ⁵ R ⁶ is preferably an amino group, a methyl amino group, an ethyl amino group, a dimethyl amino group, and a diethyl amino group, and is more preferably an amino group or a dimethyl amino group. , and diethylamino.

(式(B1-1中)，R ¹～R ⁴、m、及n與式(B1)中之該等相同。) The compound represented by the formula (B1) is preferably a compound represented by the following formula (B1-1) from the viewpoint of a high absorbance coefficient in the presence of a base. [Chem 2]

(In formula (B1-1), R ¹ to R ⁴ , m, and n are the same as those in formula (B1).)

In view of the height of the absorption coefficient in the presence of a base, in the above formula (B1) and formula (B1-1), it is preferable that at least one of R ¹ and R ³ is a hydroxyl group.

(式(B1-1a)～式(B1-1e)中，R ¹～R ⁴與式(B1)中之該等相同。) The compound represented by the formula (B1-1) is preferably a compound represented by any one of the following formulas (B1-1a) to (B1-1e). [Chem 3]

(In formula (B1-1a) to formula (B1-1e), R ¹ to R ⁴ are the same as those in formula (B1).)

Among the compounds represented by formula (B1-1a) to formula (B1-1e), the compound represented by formula (B1-1a) is preferable. Among the compounds represented by formula (B1-1a) to formula (B1-1e), it is preferable that R ² is the above-mentioned group represented by -NR ⁵ R ⁶ , and R ⁵ and R ⁶ are each independently a carbon number of 1 to 4 The following alkyl groups.

Preferred specific examples of the compound represented by the formula (B1) include the following compounds. These compounds are preferable from the viewpoint of ease of acquisition and high absorption coefficient even in the presence of a base. [chemical 4]

When the light-absorbing agent (B) contains the compound represented by the formula (B1), the ratio of the mass of the compound represented by the formula (B1) to the mass of the light-absorbing agent (B) is not particularly limited within the range that does not hinder the purpose of the present invention. limited. The ratio of the mass of the compound represented by the formula (B1) to the mass of the light absorbing agent (B) is preferably at least 70% by mass, more preferably at least 80% by mass, further preferably at least 95% by mass, most preferably at least 100% by mass %.

As a benzophenone compound, 4,4'-dicarboxybenzophenone, benzophenone-4-carboxylic acid, and tetrahydroxybenzophenone are also mentioned. These are all water-soluble ultraviolet absorbers.

(式(B2)中，R ¹¹為羥基、烷氧基、或-NR ¹²R ¹³表示之基，R ¹²及R ¹³各自獨立地為氫原子、或碳原子數1以上4以下之烷基，p為0以上3以下之整數，p為2以上之情形時，複數個R ¹¹可相同亦可不同。) As a cinnamon acid type compound, the compound represented by following formula (B2) is mentioned. The compound represented by the following formula (B2) is preferable because it enables the protective film to efficiently absorb the energy of laser light and promotes thermal decomposition of the protective film. [chemical 5]

(In formula (B2), R ¹¹ is a hydroxyl group, an alkoxy group, or a group represented by -NR ¹² R ¹³ , R ¹² and R ¹³ are each independently a hydrogen atom, or an alkyl group with 1 to 4 carbon atoms, p is an integer from 0 to 3, and when p is 2 or more, the plurality of R ¹¹ may be the same or different.)

In the above formula (B2), the alkoxy group as R ¹¹ may be linear or branched. The alkoxy group as R ¹¹ is preferably an alkoxy group having 1 to 4 carbon atoms. Specific examples of the alkoxy group as R ¹¹ are methoxy, ethoxy, n-propoxy, isopropoxy, and n-butoxy.

In the above formula (B2), R ¹¹ may be a group represented by -NR ¹² R ¹³ . R ¹² and R ¹³ are each independently a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. The alkyl groups as R ¹² and R ¹³ may be linear or branched. Specific examples of the alkyl group as ^R12 and ^R13 are methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, second-butyl, and third-butyl.

(式(B2-1)中，R ¹¹與式(B2)中之R ¹¹相同。) The compound represented by formula (B2) is preferably a compound represented by the following formula (B2-1). [chemical 6]

(In formula (B2-1), R ¹¹ is the same as R ¹¹ in formula (B2).)

Specific examples of cinnamic acid-based compounds include 4-aminocinnamic acid, 3-aminocinnamic acid, 2-aminocinnamic acid, sinapic acid (3,5-dimethoxy-4-hydroxycinnamic acid ), ferulic acid, caffeic acid. Among these, 4-aminocinnamic acid, 3-aminocinnamic acid, 2-aminocinnamic acid, and ferulic acid are preferable, and 4-aminocinnamic acid and ferulic acid are more preferable.

When the light absorbing agent (B) contains the compound represented by the formula (B2), the ratio of the mass of the compound represented by the formula (B2) to the mass of the light absorbing agent (B) is not particularly in the range that does not hinder the purpose of the present invention. limited. The ratio of the mass of the compound represented by the formula (B2) to the mass of the light absorbing agent (B) is preferably at least 70% by mass, more preferably at least 80% by mass, further preferably at least 95% by mass, most preferably at least 100% by mass %.

Specific examples of the anthraquinone-based compound include 2-carboxyanthraquinone, 2,6-anthraquinonedisulfonic acid, and 2,7-anthraquinonedisulfonic acid.

Specific examples of naphthalene-based compounds include 1,2-naphthalene dicarboxylic acid, 1,8-naphthalene dicarboxylic acid, 2,3-naphthalene dicarboxylic acid, 2,6-naphthalene dicarboxylic acid, and 2, 7-naphthalene dicarboxylic acid, etc.

As a specific example of the biphenyl compound, biphenyl-4-sulfonic acid etc. are mentioned.

Water-soluble amines, such as curcumin and EAB-F(4,4'- bis (diethylamino) benzophenone), can also be mentioned as a light absorbing agent (B).

染料、吖啶染料)、醌亞胺染料(吖𠯤染料、㗁𠯤染料、噻𠯤染料)、次甲基染料(花青染料、次甲基偶氮染料)、喹啉染料、亞硝基染料、苯醌及萘醌染料、萘二甲醯亞胺染料、紫環酮染料、及其他染料等中選擇水溶性之染料。Specific examples of water-soluble dyes include azo dyes (monoazo and polyazo dyes, metal zirconium salt azo dyes, pyrazolone azo dyes, stilbene azo dyes, thiazole azo dyes), anthraquinone Dyes (anthraquinone derivatives, anthrone derivatives), indigo dyes (indigo derivatives, thioindigo derivatives), phthalocyanine dyes, carbocation dyes (diphenylmethane dyes, triphenylmethane dyes, 𠮿

Dyes, acridine dyes), quinone imine dyes (acridine dyes, 㗁𠯤 dyes, thia𠯤 dyes), methine dyes (cyanine dyes, methine azo dyes), quinoline dyes, nitroso dyes , Benzoquinone and naphthoquinone dyes, naphthalimide dyes, perionone dyes, and other dyes, choose water-soluble dyes.

As the water-soluble pigment, from the viewpoint of low environmental load, etc., for example, edible red No. 2, edible red No. 40, edible red No. 102, edible red No. 104, edible red No. 105, edible red No. 106, edible red No. 106, edible red No. Yellow NY, Edible Yellow No. 4 Tartrazine Yellow, Edible Yellow No. 5, Edible Yellow No. 5 Sunset Yellow FCF, Edible Orange AM, Edible Vermilion No. 1, Edible Vermilion No. 4, Edible Vermilion No. 101, Edible Blue No. 1, Edible Blue No. 2, Edible Green No. 3, Edible Melon Color B, and Edible Egg Color No. 3 and other food additive pigments.

Content of the light absorbing agent (B) in a protective film forming agent is not specifically limited in the range which does not interfere with the objective of this invention. The content of the light absorbing agent (B) in the protective film forming agent is preferably from 0.05 mass % to 10 mass %. The quality of the light-absorbing agent (B) in the protective film forming agent is considered from the aspect that it is difficult to cause poor opening when the protective film is irradiated with laser light to form the processed groove, or the shape of the processed groove is deteriorated due to the heat sinking of the protective film. The ratio of the mass of the water-soluble resin (A) to the total mass of the light absorbing agent (B) is preferably from 0.5% by mass to 20% by mass, more preferably from 1% by mass to 18% by mass, still more preferably It is not less than 2% by mass and not more than 15% by mass.

The content of the light absorbing agent (B) can be set so that the absorbance of the protective film formed using the protective film forming agent becomes a desired value. The absorbance of the protective film formed using the protective film forming agent is not particularly limited. For example, the absorbance per 1 μm of film thickness at a wavelength of 355 nm of the protective film formed using the protective film forming agent is preferably 0.3 or more, more preferably 0.8 or more, and more preferably 1.0 or more.

＜Other additives＞ In addition to the water-soluble resin (A) and light absorbing agent (B), the protective film forming agent may contain other compounding agents as long as the object of the present invention is not hindered. As other formulation agents, for example, preservatives, alkaline compounds, surfactants and the like can be used.

As preservatives, benzoic acid, butylparaben, ethylparaben, methylparaben, propylparaben, benzalkonium, benzethonium chloride, benzyl alcohol, chlorine Cetylpyridinium, chlorobutanol, phenol, phenylethanol, 2-phenoxyethanol, phenylmercuric nitrate, thimerosal, m-cresol, lauryldimethylamine oxide, or combination of such.

It is preferable to use a preservative not only from the viewpoint of anticorrosion of the protective film forming agent but also from the viewpoint of reducing the load of disposal of waste liquid after semiconductor wafer cleaning. Usually, a large amount of washing water is used for washing semiconductor wafers. However, in the process using the above-mentioned protective film forming agent, there is concern about the growth of miscellaneous bacteria in the waste liquid caused by the water-soluble resin (A) contained in the protective film forming agent. Therefore, it is desirable to treat the waste liquid from the process using the above-mentioned protective film forming agent separately from the waste liquid from the process not using the protective film forming agent. However, when a preservative is contained in the protective film forming agent, the growth of miscellaneous bacteria caused by the water-soluble resin (A) is suppressed. The waste liquid of the film forming agent process is treated in the same way. Therefore, the load on the waste water treatment step can be reduced.

When the protective film forming agent contains a preservative, the content of the preservative is not particularly limited as long as it does not interfere with the object of the present invention. The content of the preservative in the protective film forming agent is preferably from 0.01 to 5 parts by mass, more preferably from 0.05 to 2 parts by mass, based on 100 parts by mass of the water-soluble resin (A).

As the basic compound, either an inorganic compound or an organic compound can be used, and examples thereof include alkylamines, alkanolamines, imidazole compounds, ammonia, or hydroxides of alkali metals. Specific examples of basic compounds include sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium silicate, sodium metasilicate, ammonia; ethylamine, n-propylamine, monoethanolamine, diethylamine, N-propylamine, diethanolamine, triethylamine, methyldiethylamine, dimethylethanolamine, triethanolamine, tetramethylammonium hydroxide, tetraethylammonium hydroxide, imidazole, 2-methylimidazole, 1,2 -Methylimidazole, N-methylimidazole, 4-methylimidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole, pyrrole, piperidine, 1,8-diazabicyclo[5, 4,0]-7-undecene, and 1,5-diazabicyclo[4,3,0]-5-nonane.

The usage-amount of a basic compound is not specifically limited in the range which does not interfere with the object of this invention. The amount of the basic compound used is preferably 1 mol or more, more preferably 1 mol or more and 20 mol or less, relative to 1 mol of the light absorbing agent (B). The lower limit of the usage amount of the basic compound may be 1.5 mol or more, 2 mol or more, or 3 mol or more relative to 1 mol of the light absorbing agent (B). The upper limit of the usage amount of the basic compound may be 15 mol or less, 10 mol or less, or 5 mol or less with respect to 1 mol of the light absorbing agent (B).

Surfactants are used, for example, to improve the defoaming properties of the protective film forming agent, the stability of the protective film forming agent, and the applicability of the coating liquid prepared from the protective film forming agent. In particular, it is preferable to use a surfactant from the viewpoint of defoaming properties when producing a protective film forming agent.

Moreover, a protective film can be formed by spin-coating the coating liquid prepared with the protective film forming agent, for example. However, there are cases where unevenness due to air bubbles occurs when the protective film is formed. In order to suppress the occurrence of such irregularities, it is preferable to use a defoamer such as a surfactant.

As the surfactant, a water-soluble surfactant can be preferably used. As the surfactant, any one of a nonionic surfactant, a cationic surfactant, an anionic surfactant, and an amphoteric surfactant can be used. The surfactant can also be polysiloxane-based. From the viewpoint of detergency, a nonionic surfactant is preferred.

＜Solvent (S)＞ The protective film forming agent contains a solvent (S) in order to dissolve or disperse the water-soluble resin (A) or the light absorbing agent (B). That is, the protective film forming agent is a solution or a dispersion of a water-soluble resin (A) and a light absorbing agent (B). The solvent (S) contains water. The solvent (S) may contain an organic solvent together with water. The solvent (S) is preferably water or an aqueous solution of an organic solvent, more preferably water, from the viewpoint of low risk such as flammability during use, or cost.

From the viewpoint of flammability, the content of the organic solvent in the solvent (S) is preferably at most 20% by mass, more preferably at most 15% by mass, further preferably at most 10% by mass.

The solvent (S) is preferably selected so that the protective film forming agent does not have a flash point at 1 atmosphere. Specifically, by adjusting the water content in the protective film forming agent, the flash point of the protective film forming agent, or the presence or absence of the flash point is adjusted. A protective film former that does not have a flash point is safer, eg, can be placed in a non-explosion-proof environment. Specifically, operations such as storage, transportation, and use of the protective film forming agent can be performed in a non-explosion-proof environment. For example, not only the introduction of the protective film forming agent into a semiconductor factory can be performed in a non-explosion-proof environment, but also the formation of the protective film can be performed in a non-explosion-proof environment. Therefore, a protective film forming agent that does not have a flash point is industrially very advantageous from the viewpoint of not requiring an explosion-proof environment such as generally expensive explosion-proof equipment.

The flash point can be obtained by measuring with a Tag closed-type method when the liquid temperature is below 80°C under 1 atmospheric pressure, and using a Cleveland open-type measurement when the liquid temperature exceeds 80°C. In this specification, even if it measures by the Cleveland open method, the case where the flash point was not measured is made into no flash point.

Examples of the organic solvent that may be contained in the protective film forming agent include methanol, ethanol, alkylene glycol, alkylene glycol monoalkyl ether, alkylene glycol monoalkyl ether acetate, and the like. As alkylene glycol, ethylene glycol, propylene glycol, etc. are mentioned. As alkylene glycol monoalkyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, etc. are mentioned. Examples of alkylene glycol monoalkyl ether acetate include ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether acetate, and propylene glycol monoethyl ether acetate. Esters etc. The protective film forming agent may contain two or more organic solvents in combination.

The solid content concentration of the protective film forming agent must be 20% by mass or more. Details will be described later, but in the present invention, a protective film is formed by applying a coating liquid obtained by diluting the protective film forming agent having a solid content concentration of 20% by mass or more. The upper limit of the solid content concentration of the protective film forming agent is not particularly limited, but is preferably 60% by mass or less, more preferably 50% by mass or less. In addition, in this specification, so-called solid content means a component other than a solvent (S).

<Coating solution preparation procedure> In the coating liquid preparation step, the above-mentioned protective film forming agent is diluted to prepare a coating liquid. That is, the coating liquid is prepared by the preparation method of the coating liquid for forming a protective film on the surface of the semiconductor wafer during dicing of the semiconductor wafer. The film forming agent is diluted, the above-mentioned protective film forming agent includes water-soluble resin (A), light absorbing agent (B) and solvent (S), the solvent (S) includes water, and the solid content concentration of the above-mentioned protective film forming agent is 20 Mass% or more.

The solid content concentration of the coating solution may be lower than that of the protective film forming agent, preferably 20% by mass or less, more preferably 15% by mass or less. The solid content concentration of the coating solution is not particularly limited, but is preferably at least 1% by mass, more preferably at least 5% by mass.

The solvent used in the dilution of the protective film forming agent is not particularly limited, and may be diluted with a solvent (S) included in the protective film forming agent, or may be diluted with a solvent not included in the protective film forming agent, or may be diluted with a protective film forming agent. The solvent (S) contained in the forming agent is diluted with a mixed solvent of a solvent not contained in the protective film forming agent, preferably the same solvent as the solvent (S) contained in the protective film forming agent. As a solvent not contained in a protective film forming agent, the said solvent (S) other than the solvent (S) contained in a protective film forming agent is mentioned.

＜Protective film formation process＞ In the protective film forming step, the coating liquid is applied on the semiconductor wafer to form a protective film. The coating liquid applied in the protective film forming step is obtained by diluting a protective film forming agent having a concentration higher than that of the coating liquid as described above. As a semiconductor wafer, a silicon substrate etc. are mentioned, for example. From the viewpoint of easy removal of the protective film by washing with water after processing, or the sufficient durability of the protective film against plasma irradiation when plasma irradiation is performed in the cutting step of the semiconductor wafer manufacturing method described later, the protective film The film thickness is typically preferably not less than 1 μm and not more than 100 μm. In the case of irradiating lasers in the processing groove forming step and/or cutting step in the manufacturing method of the semiconductor wafer described later, the film thickness of the protective film is preferably 0.1 μm or more and 10 μm or less. In the case of cutting with a blade in the cutting step, the film thickness of the protective film is not particularly limited. When cutting with a blade, the thickness of the protective film is preferably from 0.1 μm to 100 μm, for example, from the viewpoint of easy removal of the protective film by washing with water after processing.

Here, when forming a protective film by applying a protective film forming agent on a semiconductor wafer, the protective film forming agent may be applied to the semiconductor wafer after a certain amount of time has elapsed after the protective film forming agent is manufactured. Specifically, for example, there is a case where a protective film is formed using a protective film forming agent that is transported or stored for a long period of time after the protective film forming agent is produced. If the protective film forming agent is applied to the semiconductor wafer after a certain amount of time has elapsed after the protective film forming agent is manufactured in this way, the following situation exists: Compared with that, foreign matter generated in the formed protective film increases. The foreign matter in the protective film is considered to be derived from the foreign matter generated in the protective film forming agent with the lapse of time after the protective film forming agent was produced.

Usually, the generation of foreign matter over time in the solution is mostly caused by the aggregation of solutes or the reaction between solutes. However, according to the research of the present inventors, it has been unexpectedly confirmed that the solid content concentration is 20% by mass for a protective film forming agent comprising a water-soluble resin (A), a light absorbing agent (B), and a solvent (S) containing water. When the concentration is higher than 1%, it is not easy to cause the generation of foreign matter over time. Specifically, in the present invention, a protective film forming agent containing a water-soluble resin (A), a light absorbing agent (B), and a solvent (S) containing water is prepared, and the solid content concentration is 20% by mass or more, and the The coating solution obtained by diluting it is applied on a semiconductor wafer to form a protective film. Thereby, even if time elapses after manufacture of a protective film forming agent, as shown in the Example mentioned later, the increase of the foreign material of the formed protective film can be suppressed. Therefore, even if a protective film is formed after the protective film forming agent is transported or stored after the protective film forming agent is manufactured, a protective film with less foreign matter can be formed.

The reason why the increase of foreign matter in the protective film can be suppressed is not clear, but it is presumed as follows. As shown in the comparative example described later, a protective film forming agent (for example, solid content In the case of a protective film forming agent with a concentration of 10% by mass or less), if the protective film forming agent is applied to the semiconductor wafer after a lapse of time after the preparation of the protective film forming agent, foreign matter in the formed protective film will increase significantly. . On the other hand, if the above-mentioned protective film forming agent containing water-soluble resin (A), light absorbing agent (B), and solvent (S) containing water is used, and the solid content concentration is 20% by mass or more, in the production of protective film When time has elapsed from the film-forming formulation, preparing a diluted coating solution and applying the coating solution on the semiconductor wafer suppresses the increase of foreign matter in the formed protective film. Since the increase of foreign matter in the case of using a protective film forming agent with a low solid content concentration is large, it is considered that the foreign matter in the protective film may not come from the aggregation or chemical Reaction, but from other factors, such as bacteria and other bacteria.

The shorter the time between the preparation of the coating liquid and the coating of the coating liquid on the semiconductor wafer, the better. After preparing the coating liquid, it is preferably applied within one day, more preferably within one hour, and still more preferably immediately after preparation (for example, within 10 minutes). When the time from the preparation of the coating liquid to the coating of the coating liquid on the semiconductor wafer is long, foreign matter in the formed protective film tends to increase.

＜Storage/transfer procedure＞ The protective film forming method of the present invention can suppress the increase of foreign matter in the formed protective film even after time elapses after the protective film forming agent is produced. Therefore, after the protective film forming agent preparation step and before the coating liquid preparation step , may have a storage/transfer step of storing or transferring the protective film forming agent. The transfer may, for example, be conveyance or transportation using transportation machines such as ships, aircraft, railway vehicles, and trucks. The period of storage or transfer is not particularly limited, and may be longer than 1 month, or longer than 3 months. The storage or transfer temperature is not particularly limited, but is preferably -10°C or higher and 40°C or lower.

≪Semiconductor Wafer Manufacturing Method≫ The manufacturing method of a semiconductor wafer is a method including the step of manufacturing a semiconductor wafer by processing a semiconductor wafer. More specifically, the manufacturing method of a semiconductor wafer includes the following steps: a protective film forming step, forming a protective film on a semiconductor wafer by using the above protective film forming method; A processing groove forming step of irradiating laser light to a predetermined position of one or more layers including a protective film on the semiconductor wafer to form a processing groove having a pattern corresponding to the shape of the semiconductor wafer that is exposed on the surface of the semiconductor wafer; and A cutting step, which cuts off the position of the processing groove in the semiconductor wafer.

＜Protective film formation process＞ The protective film forming step is as described above. Also, the shape of the processed surface of the semiconductor wafer on which the protective film is to be formed is not particularly limited as long as desired processing can be performed on the semiconductor wafer. Typically, the processed surface of a semiconductor wafer has many irregularities. Furthermore, recessed portions are formed in regions corresponding to the tracks. In the processing surface of the semiconductor wafer, a plurality of regions corresponding to the semiconductor wafer are divided by tracks.

Hereinafter, while referring to the accompanying drawings, a method of manufacturing a semiconductor wafer using the method for forming a protective film as described above for dicing a semiconductor wafer having a plurality of semiconductor wafers divided by grid-like tracks is referred to as a semiconductor wafer manufacturing method. One of the better aspects of the method will be described.

FIG. 1 shows a perspective view of a semiconductor wafer to be processed. FIG. 2 shows an enlarged cross-sectional view of main parts of the semiconductor wafer shown in FIG. 1 . In the semiconductor wafer 2 shown in FIGS. 1 and 2 , a laminate 21 in which an insulating film and a functional film for circuits are laminated is provided on a surface 20a of a semiconductor substrate 20 such as silicon. In the laminated body 21, a plurality of semiconductor wafers 22 such as ICs and LSIs are formed in a matrix. Here, the shape and size of the semiconductor wafer 22 are not particularly limited, and can be appropriately set according to the design of the semiconductor wafer 22 .

Each semiconductor wafer 22 is divided by the tracks 23 formed in a grid pattern. Furthermore, in the illustrated embodiment, the insulating film used as the laminate 21 includes a SiO ₂ film, or an inorganic film such as SiOF or BSG (SiOB), or a polyimide-based or parylene-based film. A low dielectric constant insulator film (Low-k film) formed of an organic film of a polymer film such as (parylene) system.

The surface of the above-mentioned laminated body 21 corresponds to the surface 2a which is a processed surface. On the above-mentioned surface 2a, a protective film is formed by the above-mentioned method for forming a protective film.

In the protective film forming step, for example, a coating solution prepared by diluting a protective film forming agent is applied on the surface 2 a of the semiconductor wafer 2 using a spin coater, thereby forming the protective film 24 . In addition, the coating method of a coating liquid is not specifically limited, What is necessary is just to form the protective film of desired film thickness. The liquid coating liquid covering the surface 2a may also be dried as needed. Thereby, a protective film 24 is formed on the surface 2a on the semiconductor wafer 2 as shown in FIG. 3 .

After the protective film 24 is formed on the surface 2a of the semiconductor wafer 2 as described above, the protective tape 6 mounted on the ring-shaped frame 5 is attached to the back surface of the semiconductor wafer 2 as shown in FIG. 4 .

＜Machining groove formation process＞ In the processing groove forming step, laser light is irradiated to predetermined positions of one or more layers including the protective film 24 on the semiconductor wafer 2 to form a pattern in which the surface 20 a of the semiconductor substrate 20 is exposed and corresponds to the shape of the semiconductor wafer 22 . Processing slot.

Specifically, the laser processing device 7 is used to irradiate the surface 2 a (track 23 ) on the semiconductor wafer 2 with laser light through the protective film 24 . This irradiation of laser light is carried out using a laser light irradiation mechanism 72 as shown in FIG. 5 . In terms of intensity, the laser is preferably an ultraviolet laser with a wavelength of not less than 100 nm and not more than 400 nm. Also, YVO4 lasers and YAG lasers with wavelengths of 266 nm, 355 nm, etc. are preferred.

The above-mentioned irradiation of laser light in the processing groove forming step is performed, for example, under the following processing conditions. Furthermore, the diameter of the focused spot is appropriately selected in consideration of the width of the processing groove 25 . Laser light source: YVO4 laser or YAG laser Wavelength: 355nm Repetition frequency: 50 kHz or more and 100 kHz or less Output: 0.3 W or more and 4.0 W or less Processing feed speed: above 1 mm/sec and below 800 mm/sec

By performing the processing groove forming step described above, as shown in FIG. 6 , in the laminate 21 having the tracks 23 in the semiconductor wafer 2 , the processing grooves 25 are formed along the tracks 23 . The protective film 24 is formed by the method for forming the protective film described above, and therefore, even after time elapses after the protective film forming agent is produced, it is a protective film with little foreign matter. Therefore, it is possible to easily form grooves of a desired shape in the protective film 24 by suppressing the hindrance of the laser light by the foreign matter and irradiating the protective film 24 with the laser light as described above.

After irradiating the laser light along the prescribed track 23 as described above, the semiconductor wafer 2 held on the chuck table 71 is indexed and moved in the direction indicated by the arrow Y at the corresponding interval of the track, and the process is performed again. Exposure to laser light.

After performing laser irradiation and indexing movement on all the tracks 23 extending in the prescribed direction as described above, the semiconductor wafer 2 held on the chuck table 71 is rotated by 90 degrees, along the prescribed direction. Each of the tracks 23 extending at right angles performs laser irradiation and index movement in the same manner as described above. As described above, the processing groove 25 can be formed along all the tracks 23 formed in the laminated body 21 on the semiconductor wafer 2 .

＜Cutting procedure＞ In the cutting step, the semiconductor wafer 2 having the processing groove 25 at a position corresponding to the position of the track 23 is cut. As a preferable method, the following methods can be cited: the method of cutting the semiconductor wafer 2 by irradiating laser or plasma to the semiconductor wafer 2 equipped with the protective film 24 and the processing groove 25; A method of cutting the semiconductor wafer 2 with the film 24 or the semiconductor wafer 2 with the protective film 24 peeled off. In the case of irradiating the laser, the processing groove 25 is irradiated with the laser in order to cut the semiconductor wafer 2 . In the case of irradiating plasma, plasma is irradiated to a part or the entire surface of the surface provided with the protective film of the semiconductor wafer 2 so that the plasma is exposed to the surface of the processing tank 25 . When cutting with a blade, the semiconductor wafer 2 is cut with a blade along the position of the processing tank 25 while supplying pure water to the cutting portion. Hereinafter, a cutting method by plasma irradiation as a preferable cutting method will be described.

As shown in FIG. 7 , plasma is irradiated to the semiconductor wafer 2 provided with the protective film 24 and the processing groove 25 . Thereby, the position of the processing groove 25 in the semiconductor wafer 2 is cut off as shown in FIG. 8 . Specifically, in the semiconductor wafer 2 covered with the protective film 24, after the processing groove 25 is formed as described above, plasma irradiation is performed on the protective film 24 and the surface 20a of the semiconductor substrate 20 exposed from the processing groove 25, Thereby, the semiconductor wafer 2 is cut into the shape of the semiconductor wafer 22 , and the semiconductor wafer 2 is divided into semiconductor wafers 22 .

The plasma irradiation conditions are not particularly limited as long as cutting of the semiconductor wafer 2 at the position of the processing tank 25 can be performed satisfactorily. The plasma irradiation conditions can be appropriately set within the range of general conditions for plasma etching of semiconductor substrates in consideration of the material of the semiconductor wafer 2, the type of plasma, and the like. The gas for generating plasma during plasma irradiation is appropriately selected according to the material of the semiconductor wafer 2 . Typically, the plasma is generated using SF ₆ gas. Also, according to the so-called BOSCH process, sidewall protection by supply of C ₄ F ₆ or C ₄ F ₈ gas, etc., and etching of the semiconductor wafer 2 by plasma irradiation can be alternately carried out. Cutting of semiconductor wafer 2. According to the BOSCH process, etching with a high aspect ratio is possible, and even when the semiconductor wafer 2 is thick, it is easy to cut the semiconductor wafer 2 .

Next, as shown in FIG. 9 , the protective film 24 covering the surface of the semiconductor wafer 22 is removed. As mentioned above, since the protective film 24 is formed using the protective film forming agent containing a water-soluble resin (A), the protective film 24 can be washed off with water (or warm water).

As mentioned above, the manufacturing method of the semiconductor wafer implemented by processing a semiconductor wafer was demonstrated based on embodiment. The method for forming a protective film of the present invention, the method for manufacturing a semiconductor wafer using the method for forming a protective film, and the method for manufacturing a coating solution that can be used in the method for forming a protective film as long as they include forming a protective film on the surface of a semiconductor wafer, And the method of forming processing grooves at the positions corresponding to the tracks on the surface provided with the protective film of the semiconductor wafer can be applied to various semiconductor wafer manufacturing methods. [Example]

Hereinafter, the present invention will be specifically described with reference to examples and comparative examples. The present invention is not limited by the following examples.

又，作為防腐劑，使用了對羥基苯甲酸甲酯(C-1)。 又，作為溶劑(S)，使用了水(S1)90質量份與丙二醇單甲基醚(PGME)(S2)10質量份之混合溶劑。 (Examples 1-11, and Comparative Examples 1-2) In Examples 1-11, and Comparative Examples 1-2, as the water-soluble resin (A), polyvinylpyrrolidone (A-1), Hydroxypropylcellulose (A-2). Moreover, B-1 (ferulic acid) represented by the following formula was used as a light absorbing agent (B). [chemical 7]

Also, as a preservative, methylparaben (C-1) was used. Moreover, the mixed solvent of 90 mass parts of water (S1) and 10 mass parts of propylene glycol monomethyl ether (PGME) (S2) was used as a solvent (S).

＜Manufacture of protective film forming agent＞ Water-soluble resin (A), light absorbing agent (B) and preservative of the type and amount described in Table 1, and solvent (S) in an amount to achieve the solid content concentration described in Table 1 were put into the container, and the After stirring for 8 hours, the protective film forming agents of the respective examples and comparative examples were obtained.

＜Formation of protective film (coating film)＞ In Examples 1 to 10, the protective film forming agent was diluted with a solvent (S) immediately after production (within 10 minutes) to prepare a coating solution having a solid content concentration of 10% by mass, and immediately after preparing the coating solution (within 10 minutes). Minutes), apply the coating solution on the silicon substrate by spin coating (spin coating conditions: 1000 rpm, 60 seconds), thereby forming a protective film 1 with a film thickness of 1 μm. In Examples 1 to 10, after storing the protective film forming agent at 40°C for 3 months, it was diluted with a solvent (S) to prepare a coating solution having a solid content concentration of 10% by mass. Immediately after preparing the coating solution (within 10 minutes), the coating solution was applied to the silicon substrate by spin coating (spin coating conditions: 1000 rpm, 60 seconds), thereby forming a protective film 2 with a film thickness of 1 μm. Also, in Example 11, the solid content concentration of each coating solution was 20% by mass, and the spin coating conditions were 2000 rpm and 60 seconds. In the same manner as in Examples 1 to 10, a film thickness of 3 μm protective film 1 and protective film 2. Moreover, in each comparative example, the protective film 1 and the protective film 2 with a film thickness of 1 micrometer were formed respectively similarly to Examples 1-10 except not carrying out the operation of diluting with a solvent (S).

＜Evaluation of foreign matter on the protective film＞ The formed protective film 1 and protective film 2 were observed with NSX-220 (manufactured by Rudolph Co., Ltd.), the number of foreign matter was counted, and the increase rate (%) of foreign matter was calculated|required by the following formula. The case where the increase rate of foreign matter was less than 5% was judged as ○, and the case where the increase rate of foreign matter was 5% or more was judged as ×. The results are shown in Table 1. Increase rate of foreign matter (%)=[{(number of foreign matter in protective film 2)/(number of foreign matter in protective film 1)}－1]×100

[Table 1] Water-soluble resin (A) Light absorbing agent (B) preservative Solid content concentration of protective film forming agent Foreign body evaluation type parts by mass type parts by mass type parts by mass quality% Example 1 A-1 100 B-1 3 - none 50 〇 Example 2 A-1 100 B-1 3 - none 30 〇 Example 3 A-1 100 B-1 3 - none 20 〇 Example 4 A-1 100 B-1 3 C-1 0.1 50 〇 Example 5 A-1 100 B-1 3 C-1 0.1 20 〇 Example 6 A-2 100 B-1 3 - none 40 〇 Example 7 A-2 100 B-1 3 - none 30 〇 Example 8 A-2 100 B-1 3 - none 20 〇 Example 9 A-2 100 B-1 3 C-1 0.1 40 〇 Example 10 A-2 100 B-1 3 C-1 0.1 20 〇 Example 11 A-1 100 B-1 3 - none 50 〇 Comparative example 1 A-1 100 B-1 3 - none 10 x Comparative example 2 A-2 100 B-1 3 - none 10 x

According to Table 1, a coating solution obtained by diluting a protective film forming agent containing a water-soluble resin (A), a light absorbing agent (B), and a solvent (S) containing water, and having a solid content concentration of 20% by mass or more In Examples 1 to 11 coated on semiconductor wafers (silicon substrates), the rate of increase of foreign matter in the formed protective film was low. Therefore, it turns out that Examples 1-11 can suppress the foreign material which generate|occur|produced in the formed protective film even if time passes after manufacture of a protective film forming agent. On the other hand, according to Table 1, the rate of increase of foreign matter in Comparative Examples 1 and 2, which did not perform dilution, was higher than that of Examples.

2: Semiconductor wafer 2a: Surface of semiconductor wafer 3: Spin coater 5: Ring frame 6: Protective tape 7:Laser processing device 20: Substrate 20a: The surface of the substrate 21: laminated body 22: Semiconductor wafer 23: Trace 24: Protective film 25:Laser processing groove 26: cutting groove 71: Chuck table of laser processing device 72:Laser light irradiation mechanism

FIG. 1 is a perspective view showing a semiconductor wafer processed by a method for manufacturing a semiconductor wafer using a method for forming a protective film of the present invention. FIG. 2 is an enlarged cross-sectional view of the semiconductor wafer shown in FIG. 1 . 3 is an enlarged cross-sectional view of main parts of a semiconductor wafer on which a protective film is formed. 4 is a perspective view showing a state in which a semiconductor wafer on which a protective film is formed is supported by a ring-shaped frame through a protective tape. Fig. 5 is a perspective view of main parts of a laser processing device implementing the step of irradiating laser light. 6 is an enlarged cross-sectional view of a semiconductor wafer provided with a protective film and processing grooves formed by irradiation of laser light. FIG. 7 is an explanatory view showing plasma irradiation to the semiconductor wafer shown in FIG. 6 . 8 is an enlarged cross-sectional view showing a state in which a semiconductor wafer is divided into semiconductor wafers by plasma irradiation. Fig. 9 is an enlarged cross-sectional view showing a state where the protective film on the semiconductor wafer is removed.

2: Semiconductor wafer

2a: Surface of semiconductor wafer

20: Substrate

23: Trace

Claims (6)

A method for forming a protective film, which is to form a protective film on the surface of a semiconductor wafer during dicing of the semiconductor wafer, comprising: A protective film forming agent preparation step, which prepares a protective film forming agent comprising a water-soluble resin (A), a light absorbing agent (B) and a solvent (S), the solvent (S) comprising water, and the above The solid content concentration of the protective film forming agent is 20% by mass or more; a coating solution preparation step of diluting the protective film forming agent to prepare a coating solution; and The protective film forming step is to apply the above-mentioned coating solution on the semiconductor wafer to form a protective film. The method for forming a protective film according to claim 1, wherein in the step of preparing the coating solution, the protective film forming agent is diluted with the solvent (S). The method for forming a protective film according to claim 1, wherein the solvent (S) includes an organic solvent. The method for forming a protective film according to claim 1, wherein after the step of preparing the protective film forming agent and before the step of preparing the coating solution, there is a storage/transfer step of storing or transferring the protective film forming agent. A method of manufacturing a semiconductor wafer, which involves processing a semiconductor wafer, comprising: A protective film forming step, which uses the method for forming a protective film according to any one of claims 1 to 4 to form a protective film on the above-mentioned semiconductor wafer; A processing groove forming step of irradiating laser light to predetermined positions on the semiconductor wafer including one or more layers of the protective film to form a pattern corresponding to the shape of the semiconductor wafer with the surface of the semiconductor wafer exposed slot; and A cutting step, which cuts off the positions of the processing grooves in the semiconductor wafer. A method for preparing a coating liquid, the above coating liquid is used to form a protective film on the surface of a semiconductor wafer during dicing of the semiconductor wafer, The preparation method has a dilution step of diluting a protective film forming agent comprising a water-soluble resin (A), a light absorbing agent (B) and a solvent (S), wherein the solvent (S) comprises water, And the solid content concentration of the said protective film forming agent is 20 mass % or more.

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