JP7043173B2 - A method for manufacturing a protective film base material for dicing, a protective film composition for dicing, a protective sheet for dicing, and a wafer to be processed. - Google Patents

Description

The present invention relates to a protective film base material for dicing used when dicing a wafer, a protective film composition for dicing, a protective sheet for dicing, and a method for producing a wafer to be processed.

If the circuit forming surface of the wafer is exposed in the dicing process of the wafer, contaminants such as cutting water during dicing and cutting debris generated by cutting the wafer adhere to the circuit forming surface, and the circuit forming surface is contaminated. Will end up.

Therefore, various proposals have been made in which a protective film is formed on the entire surface of the wafer, the wafer is diced together with the protective film, and then the protective film is removed from the diced wafer. As a result, it is possible to prevent the circuit forming surface of the wafer from coming into direct contact with the contaminants, and to prevent contamination of the circuit forming surface. For example, Patent Document 1 proposes a protective film for dicing, which comprises a solution in which a water-soluble resin and a water-soluble laser light absorber are dissolved.

Japanese Unexamined Patent Publication No. 2006-140311

However, since the protective film for dicing described in Patent Document 1 is water-soluble, it is not suitable for dicing such as blade dicing using water. Therefore, for such dicing, it is conceivable to use a water-insoluble protective film for dicing. However, for removing the water-insoluble protective film for dicing, it is common to use a release agent composed of an organic solvent, which is not desirable in terms of work environment and the like.

The present invention provides a protective film base material for dicing, which has excellent water resistance during dicing and is easy to remove with a water-based release agent, a protective film composition for dicing, a protective sheet for dicing, and a method for producing a wafer to be processed. The purpose is.

The present inventors have found that a copolymer containing a monomer constituent unit derived from an acid anhydride can impart water resistance to a dicing film-retaining film and at the same time can be removed by an alkaline solution which is an aqueous release agent. , The present invention has been completed.

The first aspect of the present invention is a protective film base material for dicing, which is made of a copolymer containing a monomer constituent unit derived from acid anhydride.

According to the present invention, a method for producing a protective film base material for dicing, a protective film composition for dicing, a protective sheet for dicing, and a wafer to be processed, which has excellent water resistance during dicing and is easy to remove with a water-based release agent. Can be provided.

3 is a graph showing the dissolution rate of the protective film when the protective film of Example 2 is immersed in an aqueous ammonia solution having a different pH and concentration.

Hereinafter, embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments. The present invention can be carried out with appropriate modifications within the scope of the object.

<Protective film base material for dicing>
The protective film base material for dicing according to the present embodiment (hereinafter, may be simply referred to as “base material”) is made of a copolymer containing a monomer constituent unit derived from acid anhydride.

Since the protective film containing the substrate according to the present embodiment is made of a copolymer containing a monomer constituent unit derived from acid anhydride, it has excellent water resistance during dicing using neutral water and protects the wafer. .. Further, since the ring structure in the monomer constituent unit derived from acid anhydride of this base material is opened in an alkaline solution and can be dissolved in water, the protective film containing this base material contains an organic solvent. It can be removed with an alkaline aqueous solution without using it.

Examples of such a monomer constituent unit derived from acid anhydride (hereinafter, may be simply referred to as “acid anhydride monomer”) include carboxylic acid anhydride. Examples of the carboxylic acid anhydride include maleic anhydride, itaconic anhydride, acetic anhydride, propionic anhydride, oxalic anhydride, succinic anhydride, phthalic anhydride, benzoic anhydride and the like, and maleic anhydride is preferable. These may be used alone in the copolymer, or may be used in combination of two or more.

The acid anhydride monomer is contained in a ratio of preferably 30 mol% or more, more preferably 40 mol% or more, still more preferably 50 mol% or more, based on all the monomer constituent units of the copolymer. By containing the acid anhydride monomer in a ratio of 30 mol% or more, it becomes easy to balance water resistance and alkali solubility. If the acid anhydride monomer is too small, it tends to be difficult to impart water resistance to the substrate or to remove it with an alkaline solution. The upper limit of the ratio of the acid anhydride monomer is not particularly limited, but is preferably 95 mol% or less, more preferably 90 mol% or less, and more preferably 85 mol% or less with respect to all the monomer constituent units of the copolymer. be.

The above-mentioned copolymer contains other monomer constituent units other than the acid anhydride monomer. Examples of other monomer constituent units include a monomer constituent unit derived from a hydrophobic monomer and a monomer constituent unit derived from a hydrophilic monomer. From the viewpoint of improving the water resistance of the protective film, it is preferable that the copolymer further contains a monomer constituent unit derived from a hydrophobic monomer. Further, from the viewpoint of increasing the solubility of the protective film in the alkaline solution, the copolymer may further contain a monomer constituent unit derived from a hydrophilic monomer.

Examples of the monomer constituent unit derived from the hydrophobic monomer (hereinafter, may be simply referred to as “hydrophobic monomer”) include styrene and acrylic acid esters (for example, methyl, ethyl, propyl, isopropyl, sec-butyl, ter-). Butyl, isobutyl, allyl, phenyl, benzyl, lauryl, stearyl ester, etc.), methacrylic ester (eg, methyl, ethyl, propyl, isopropyl, sec-butyl, ter-butyl, isobutyl, allyl, phenyl, benzyl, lauryl, stearyl, etc.) Esters, etc.), α-methylstyrene, vinyl acetate, vinyl chloride, etc. may be mentioned. These may be used alone in the copolymer, or may be used in combination of two or more. As will be described later, styrene, acrylic acid and / or methacrylic acid ester are preferably mentioned as the alkali-soluble monomer in that an alkaline solution is used as the aqueous stripping agent.

The hydrophobic monomer is contained in a ratio of preferably 5 mol% or more, more preferably 10 mol% or more, and more preferably 15 mol% or more with respect to all the monomer constituent units of the copolymer. On the other hand, the hydrophobic monomer is contained in a ratio of preferably 70 mol% or less, more preferably 60 mol% or less, and more preferably 50 mol% or less with respect to all the monomer constituent units of the copolymer. By including the hydrophobic monomer in the above range, the water resistance of the protective film can be improved. If the ratio of hydrophobic monomers is too large, it tends to be difficult to remove with an alkaline solution.

The weight average molecular weight of the copolymer (which is the styrene-equivalent weight average molecular weight by GPC) is not particularly limited, but may be, for example, 20000 or less, specifically 15000 or less, 10000 or less. The upper limit is not particularly limited, but may be, for example, 1000 or more, specifically 3000 or more, 5000 or more. When the weight average molecular weight of the copolymer is in the above range, it is easy to adjust the viscosity of the base material and to secure the film thickness of the protective film.

The dissolution viscosity of the copolymer at 200 ° C. is not particularly limited, but is preferably 100,000 poise or less, more preferably 60,000 poise or less. The lower limit is not particularly limited, but may be, for example, 100 poise or more, specifically 1000 poise or more, 2000 poise or more.

The glass transition point of the copolymer is not particularly limited, but may be, for example, 70 ° C. or higher, specifically 100 ° C. or higher, 110 ° C. or higher, 120 ° C. or higher. The upper limit is not particularly limited, but may be, for example, 200 ° C. or lower, specifically 160 ° C. or lower.

The acid value of the copolymer is not particularly limited, but may be, for example, 90 or more, specifically 200 or more, or 250 or more, from the viewpoint of enhancing the solubility of the protective film in the alkaline solution. The upper limit is not particularly limited, but may be 600 or less, specifically 550 or less, or 500 or less.

<Protective film composition for dicing>
The protective film composition for dicing according to the present embodiment (hereinafter, may be simply referred to as a protective film composition) contains the above-mentioned base material and a solvent. Since the protective film composition according to the present embodiment contains the above-mentioned base material, it has excellent water resistance during dicing and can be easily removed by a water-based release agent.

The protective film composition can be applied to the processed surface of the wafer by a method such as spin coating and dried to form a protective film.

If the protective film is thick, it may be difficult to remove the protective film with an alkaline solution. However, since the protective film of the present invention has excellent solubility in an alkaline solution, even a relatively thick protective film can be used during dicing. Is given sufficient protection. In addition, it may be difficult to form an excessively thick protective film due to restrictions on the soluble amount and viscosity of the base material used. On the other hand, if the film thickness of the protective film is thin, the protective property at the time of dicing may be insufficient, but since the protective film of the present invention is excellent in water resistance, a relatively thin film thickness may be sufficient. Therefore, it is preferable that the protective film composition according to the present embodiment is used for forming a protective film having the following film thickness. The lower limit of the film thickness of the protective film is not particularly limited, but is preferably 50 nm or more, more preferably 100 nm or more, and 150 nm or more.
The upper limit of the film thickness of the protective film is not particularly limited, but is preferably 1000 nm or less, more preferably 800 nm or less.

The solvent contained in the protective film composition is not particularly limited as long as it can dissolve the copolymer, but it is not particularly limited, but it is an inorganic solvent such as ammonia, sodium hydroxide, potassium hydroxide, an aliphatic amine, an aromatic amine, or a heterocycle. Examples thereof include organic amine compounds such as the formula amine and amine-based solvents such as organic ammonium salts such as quaternary ammonium hydroxide. Among them, ammonia and alkaline amine-based solvents are preferable, and quaternary ammonium hydroxide is more preferable, because the above-mentioned base material can be easily dissolved in a large amount.

The pH of the solvent may vary depending on the alkaline solution used, but is preferably pH 7.5 or higher, more preferably pH 7.5 or higher, because a sufficient amount of the base material can be dissolved and a protective film having a desired film thickness can be easily formed. The pH is 9 or higher. On the other hand, since the substrate used in the present invention has excellent solubility in an alkaline solution, it is less necessary to use an alkaline solution having an excessively high pH. Therefore, the upper limit of the pH is not particularly limited, but the pH is preferably 13 or less, more preferably 12 or less, or 11 or less from the viewpoint of handling and the like. For example, in the case of an aqueous ammonia solution, the lower limit of pH is preferably 10.5 or more, more preferably pH 10.7 or more, and the upper limit is preferably 13 or less, more preferably 12 or less, 11 or less. In the case of an aqueous solution of tetramethylammonium hydroxide (TMAH), the lower limit of pH is preferably 10 or more, more preferably 11 or more, and the upper limit is preferably 13 or less, more preferably 12 or less.

Specific examples of the aliphatic amine include monoethanolamine, diethanolamine, triethanolamine, methylamine, ethylamine, propylamine, isopropylamine, butylamine, isobutylamine, tert-butylamine, pentylamine, isopentylamine and tert. -Pentylamine, hexylamine, heptylamine, octylamine, dimethylamine, diethylamine, dipropylamine, diisopropylamine, trimethylamine, triethylamine, tripropylamine, triisopropylamine, tributylamine, triisobutylamine, tritert-butylamine, tri Examples thereof include pentylamine, triisopentylamine, tritert-pentylamine, trihexylamine, triheptylamine, trioctylamine and the like.

Specific examples of the aromatic amine include benzylamine, aniline, N-methylaniline, N, N-dimethylaniline, o-methylaniline, m-methylaniline, p-methylaniline, and N, N-diethylaniline. , Diphenylamine, di-p-tolylamine and the like.

Specific examples of the heterocyclic amine include pyridine, o-methylpyridine, o-ethylpyridine, 2,3-dimethylpyridine, 4-ethyl-2-methylpyridine, 3-ethyl-4-methylpyridine and the like. Can be mentioned.

Specific examples of the quaternary ammonium hydroxide include tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, trimethylethylammonium hydroxide, and dimethyldiethylammonium. Hydroxydo, trimethyl (hydroxyethyl) ammonium hydroxide, dimethyldi (hydroxyethyl) ammonium hydroxide and the like can be mentioned.

Specific examples of the quaternary ammonium hydroxide include tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, trimethylethylammonium hydroxide, and dimethyldiethylammonium. Hydroxydo, trimethyl (hydroxyethyl) ammonium hydroxide, dimethyldi (hydroxyethyl) ammonium hydroxide and the like can be mentioned.

The amount of the solvent used is not particularly limited, but is appropriately set according to the coating film thickness within a range in which the protective film composition has a concentration that can be applied to the wafer. Specifically, it is preferable to use the protective film composition so that the solid content concentration is in the range of 2% by mass or more and 30% by mass or less, preferably 5% by mass or more and 20% by mass or less.

<Protective sheet for dicing>
The protective sheet for dicing according to the present embodiment (hereinafter, may be simply referred to as a protective sheet) includes a protective layer containing the above-mentioned base material. The protective sheet according to this embodiment is attached and used on the processed surface of the wafer. Since the protective sheet according to the present embodiment contains the above-mentioned base material, it has excellent water resistance during dicing and can be easily removed by an alkaline solution.

If the protective film has a large thickness, it may be difficult to remove the protective film with an alkaline solution. However, since the protective film of the present invention has excellent solubility in an alkaline solution, a relatively thick protective film may be used, thereby dicing. Sufficient protection of time is given. In addition, it may be difficult to form an excessively thick protective film due to restrictions on the soluble amount and viscosity of the base material used. On the other hand, if the film thickness of the protective film is thin, the protective property at the time of dicing may be insufficient, but since the protective film of the present invention is excellent in water resistance, a relatively thin film thickness may be sufficient. Therefore, the lower limit of the layer thickness of the protective film is not particularly limited, but is preferably 50 nm or more, more preferably 100 nm or more, and 150 nm or more. The lower limit of the layer thickness of the protective layer is not particularly limited, but is preferably 50 nm or more, more preferably 100 nm or more. The upper limit of the layer thickness of the protective layer is not particularly limited, but is preferably 500 nm or less, more preferably 300 nm or less.

In addition to the protective layer, the protective sheet according to the present embodiment may include other layers such as an adhesive layer and an elastic layer, which are used for ordinary protective sheets. Further, the protective sheet may include a release sheet that is peeled off when the protective sheet is attached onto the processed surface of the wafer.

The pressure-sensitive adhesive layer is not particularly limited as long as it can be attached to the processed surface of the wafer and can be removed by an alkaline solution, and is not particularly limited, and is known as a known rubber resin, acrylic resin, etc., as well as known fillers and known materials. Adhesives containing various additives can be used.

<Manufacturing method of wafer to be processed>
The method for manufacturing a wafer to be processed according to the present embodiment is a step of dicing the protective film and the processed surface in a state where the protective film containing the above-mentioned base material is formed on the processed surface of the wafer (hereinafter, "dicing step"). It has a step of bringing the protective film into contact with an alkaline solution and removing it from the processed surface of the wafer (hereinafter, may be referred to as a "removal step").

As described above, in the method for producing a wafer to be processed according to the present embodiment, since the protective film contains a base material made of a copolymer containing a monomer constituent unit derived from acid anhydride, neutral water is used in the dicing step. It is possible to protect the processed surface of the wafer from contaminants even in the case of using. In addition, since the protective film can be removed with an alkaline solution in the removal step, it is not necessary to use an organic solvent, which is significant in terms of working environment such as treatment of chemicals.

The type of wafer is not particularly limited, and the wafer has a problem of adhesion of contaminants to the processed surface of the wafer, for example, a semiconductor element such as a memory composed of transistors, capacitors and resistors, and a logic circuit. Examples thereof include those in which various semiconductor elements such as a solid-state image pickup element, a thermoelectric conversion element, and a photoelectric conversion element are formed. Examples of the semiconductor wafer include a wafer made of a semiconductor such as silicon and germanium, and a compound semiconductor such as silicon germanium, GaAs and InGaAs.

The method for forming the protective film on the wafer is not particularly limited, and the protective film may be formed by applying and drying the above-mentioned protective film composition by a method such as spin coating, or a protective sheet is attached. By doing so, a protective film may be formed.

If the protective film has a large thickness, it may be difficult to remove the protective film with an alkaline solution. However, since the protective film of the present invention has excellent solubility in an alkaline solution, a relatively thick protective film may be used, thereby dicing. Sufficient protection of time is given. In addition, it may be difficult to form an excessively thick protective film due to restrictions on the soluble amount and viscosity of the base material used. On the other hand, if the film thickness of the protective film is thin, the protective property at the time of dicing may be insufficient, but since the protective film of the present invention is excellent in water resistance, a relatively thin film thickness may be sufficient. Therefore, the lower limit of the film thickness of the protective film is not particularly limited, but is preferably 50 nm or more, more preferably 100 nm or more, and 150 nm or more.

[Dicing process]
The dicing step is a step of cutting the wafer and the protective film into small pieces at once to form chips, and can be performed using a known dicing device. For example, do as follows. First, a dicing sheet is attached to the entire back surface of the wafer on which the protective film is formed opposite to the processed surface, and the dicing sheet is attached to the wafer ring of the dicing device. Then, the wafer and the protective film are collectively cut along the dicing line while water is discharged to the cutting portion by the rotary blade to which the diamond fine particles of the dicing device are attached. As a result, the wafer is made into chips while being attached to the dicing sheet.

Since the protective film according to the present embodiment has excellent water resistance, it can protect the processed surface of the wafer without melting even in dicing using a large amount of water, for example, blade dicing.

[Removal process]
The removal step is a step of bringing the protective film into contact with a stripping solution made of an alkaline solution to remove the protective film from the wafer. For example, the wafer as it is attached to the wafer ring described above (attached to the dicing sheet) is immersed in a stripping solution consisting of an alkaline solution and stirred as necessary. As a result, the protective film and cutting debris and diamond fine particles generated in the dicing process can be easily removed at the same time. At this time, since the protective film used in the present invention has excellent solubility in an alkaline solution, it can be removed in a short time even under mild conditions, for example, at 5 to 30 ° C. for 5 to 600 seconds (specifically, 300). It may be performed in seconds or less, 200 seconds or less, 100 seconds or less, 50 seconds or less, 20 seconds or less, and 15 seconds or less).

Examples of the alkaline solution used as the release agent include those of the same type as the solvent that can be used in the protective film composition. Ammonia and alkaline amine solvents are preferable, and quaternary ammonium hydroxides are more preferable, because the protective film can be easily removed quickly.

The pH of the alkaline solution used as the release agent may differ depending on the alkaline solution used, but is preferably pH 7.5 or higher, more preferably pH 9 or higher, because the protective film can be dissolved quickly. On the other hand, since the protective film used in the present invention is excellent in solubility in an alkaline solution, it is less necessary to use an alkaline solution having an excessively high pH. Therefore, the upper limit of the pH is not particularly limited, but the pH is preferably 13 or less, more preferably 12 or less, or 11 or less from the viewpoint of handling and the like. For example, in the case of an aqueous ammonia solution, the lower limit of pH is preferably 10.5 or more, more preferably pH 10.7 or more, and the upper limit is preferably 13 or less, more preferably 12 or less, 11 or less. In the case of an aqueous solution of tetramethylammonium hydroxide (TMAH), the lower limit of pH is preferably 10 or more, more preferably 11 or more, and the upper limit is preferably 13 or less, more preferably 12 or less.

The concentration of the alkaline solution used as the release agent varies depending on the alkaline solution used, but is preferably 0.01% by mass or more, more preferably 0.08% by mass or more. The upper limit is not particularly limited, but when it exceeds a predetermined value, the dissolution rate also saturates. For example, in the case of an aqueous ammonia solution, the lower limit of the concentration is preferably 0.01% by mass or more, more preferably 0.08% by mass or more, while the upper limit is preferably 10% by mass or less, more preferably. Is 1% by mass or less, 0.5% by mass or less, 0.2% by mass or less, and 0.1% by mass or less.

As described above, the present invention can dissolve at high speed, specifically, dissolution of 60 nm film thickness / sec or more, 100 nm film thickness / sec or more, 140 nm film thickness / sec or more, 170 nm film thickness / sec or more. Speed is mentioned.

After the removal step, the wafer to be processed can be completed by separating each chip from the dicing sheet as needed. After that, the semiconductor can be completed by arbitrarily mounting each chip on the package, bonding, sealing the package, and the like.

Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited to these Examples.

[Example 1]
(Preparation of protective film composition)
4 parts by mass of a styrene maleic anhydride copolymer (molecular weight: 5500, trade name: SMA-1000, manufactured by Kawahara Yuka Co., Ltd.) is dissolved in 90 parts by mass of a 4% by mass aqueous ammonia solution, and a filter having a pore size of 0.4 μm is used. Filtering was performed to prepare a protective membrane composition.

(Formation of protective film)
The protective film composition was applied onto a silicon wafer while adjusting the rotation speed with a spin coater, and dried at 100 ° C. for 30 seconds to obtain a protective film having a film thickness of 110 nm.

[Example 2]
The protective film composition obtained in Example 1 was applied onto a silicon wafer while adjusting the rotation speed with a spin coater, and dried at 100 ° C. for 30 seconds to obtain a protective film having a film thickness of 170 nm.

[Evaluation 1]
The protective film on the silicon wafer obtained in Examples 1 and 2 was coated with various solutions at 23 ° C. (deionized water, 5% by mass ammonia aqueous solution (NH ₃ aq)), 2.38% by mass of tetramethylammonium hydroxide. It was immersed in an aqueous solution (TMAH)) and the solubility of the protective film was evaluated.

It was confirmed that the protective films of Examples 1 and 2 had a high protective effect against deionized water without film loss. On the other hand, it was confirmed that both of them can be removed within 10 seconds by using an aqueous solution of ammonia or an aqueous solution of tetramethylammonium hydroxide as an aqueous release agent.

[Evaluation 2]
The protective film on the silicon wafer obtained in Example 2 was immersed in an aqueous ammonia solution (23 ° C.) having a different concentration and pH, and a dissolution test of the protective film was performed. The results are shown in FIG.

From the results of FIG. 1, it was confirmed that the protective film obtained in Example 2 can be removed by an aqueous ammonia solution of 0.01% by mass or more. In particular, in the dissolution test with a 0.08 mass% aqueous ammonia solution, a dissolution rate of 40 nm film thickness / sec can be obtained, and in the dissolution test with a 0.1 mass% aqueous ammonia solution, a dissolution rate of 170 nm film thickness / sec can be obtained. It was confirmed that the dissolution rate was almost saturated even when an aqueous ammonium solution having a higher concentration was used.

[Example 3]
4 parts by mass of a styrene maleic anhydride copolymer (molecular weight: 9500, trade name: SMA-3000, manufactured by Kawahara Yuka Co., Ltd.) is dissolved in 90 parts by mass of a 4% by mass aqueous ammonia solution, and a filter having a pore size of 0.4 μm is used. Filtering was performed to prepare a protective membrane composition. Then, in the same manner as in Example 1, the film was applied onto a silicon wafer while adjusting the rotation speed with a spin coater, and dried at 100 ° C. for 30 seconds to obtain a protective film having a film thickness of 900 nm.

[Comparative Example 1]
The polyvinyl alcohol described in [0064] of JP-A-2006-140311 was dissolved in pure water to obtain a composition for a protective film having a solid content concentration of 10% by mass. Then, in the same manner as in Example 1, the film was applied onto a silicon wafer while adjusting the rotation speed with a spin coater, and dried at 100 ° C. for 30 seconds to obtain a protective film having a film thickness of 1400 nm.

[Comparative Example 2]
An organic solvent peeling type negative resist material (trade name: OMR100, manufactured by Tokyo Ohka Kogyo Co., Ltd.) is applied onto a silicon wafer while adjusting the rotation speed with a spin coater in the same manner as in Example 1, and 60 at 120 ° C. It was dried for seconds and exposed (500 mJ / cm ² (ghi line)) to obtain a protective film having a film thickness of 1300 nm.

[Evaluation 4]
23 The protective films of Examples 3 and Comparative Examples 1 and 2 were added to various solutions (deionized water, 5% by mass of ammonia aqueous solution (NH ₃ aq), 2.38% by mass of tetramethylammonium hydroxide aqueous solution (TMAH)). The solution was immersed at ° C for 10 minutes, and the solubility of each protective film was examined. The results are shown in Table 1. The evaluation criteria in Table 1 are as follows.
◎: Starts to dissolve within 1 second 〇: Starts to dissolve within 3 seconds ×: Does not dissolve

From the results in Table 1, the protective film of Example 3 is not soluble in deionized water and has excellent water resistance, and is easily soluble in an aqueous ammonia solution or an aqueous solution of tetramethylammonium hydroxide and has excellent removability. Was confirmed. On the other hand, it was confirmed that the protective film of Comparative Example 1 was soluble in an aqueous ammonia solution or an aqueous solution of tetramethylammonium hydroxide, but was easily dissolved in deionized water, and water resistance could not be obtained. Further, it was confirmed that the protective film of Comparative Example 2 was difficult to dissolve in any of pure water, an aqueous solution of ammonia, and an aqueous solution of tetramethylammonium hydroxide, and was difficult to remove with an aqueous release agent.

Claims (8)

A processed surface for dicing consisting of a copolymer containing a monomer constituent unit derived from an acid anhydride and a monomer constituent unit derived from a hydrophobic monomer and not containing a monomer constituent unit in which an alkali-soluble group is blocked by an alkyl vinyl ether. It is a protective film base material and
The hydrophobic monomer contains styrene and contains
A base material in which the ratio of the monomer constituent units derived from the acid anhydride is 25 mol% or more and 95 mol% or less with respect to all the monomer constituent units of the copolymer. The substrate according to claim 1 , wherein the copolymer has a weight average molecular weight of 3000 or more and 20000 or less. The base material according to claim 1 or 2 , which is a protective film base material for blade dicing. A protective film substrate for dying, which comprises a monomer constituent unit derived from an acid anhydride and does not contain a monomer constituent unit in which an alkali-soluble group is blocked by an alkyl vinyl ether, and is derived from the acid anhydride. The ratio of the monomer constituent units of the above is 25 mol% or more and 95 mol% or less with respect to all the monomer constituent units of the copolymer .
With solvent
Including
A protective film composition for dicing in which the solvent is ammonia and / or an alkaline amine-based solvent . A machined surface protective sheet for dicing, comprising a protective layer containing the substrate according to any one of claims 1 to 3 . A step of dicing the protective film and the processed surface in a state where the protective film containing the base material is formed on the processed surface of the wafer.
It has a step of bringing the protective film into contact with an alkaline solution and removing it from the processed surface.
The base material is a protective film base material for dying, which comprises a copolymer containing a monomer constituent unit derived from an acid anhydride and containing no monomer constituent unit in which an alkali-soluble group is blocked by an alkyl vinyl ether. The ratio of the monomer constituent units derived from the acid anhydride is 25 mol% or more and 95 mol% or less with respect to all the monomer constituent units of the copolymer.
Manufacturing method of wafer to be processed. The method according to claim 6 , wherein the alkaline solution contains an alkaline amine-based solvent. The method according to claim 6 or 7 , wherein the removal is performed at a rate of 60 nm film thickness / sec or more.

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