JP2002296788A - Method for forming chemical amplification type resist pattern - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for forming a resist pattern having a square cross section and superior dimensional fidelity while suppressing deterioration in the sensitivity and resolution with time in a chemical amplification type resist film formed on a substrate. SOLUTION: In the method for forming a chemical amplification type resist pattern by photolithography, a chemical amplification type resist film is formed on a substrate and then a film consisting of an aromatic ring-containing polymer which may be substituted with halogens is applied thereon. Then a latent image pattern is formed and developed to form the chemical amplification type resist pattern.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for forming a chemically amplified resist pattern. More specifically, the present invention relates to a method for forming a resist pattern suitably applied to the production of a photomask used particularly in the manufacture of a semiconductor device or the like, the method comprising storing a chemically amplified resist film formed on a substrate. The present invention relates to a method for efficiently forming a chemically amplified resist pattern having a rectangular cross-section and excellent dimensional fidelity while suppressing deterioration of sensitivity and resolution over time during and during transportation.

[0002]

2. Description of the Related Art In recent years, miniaturization of processing by photolithography has been used as a means for improving the degree of integration of semiconductor devices. The miniaturization by the photolithography is performed by, for example, using g-line to i-line, i-line to KrF excimer laser light, or KrF excimer laser light to ArF
Excimer laser light has been achieved by shortening the wavelength of the exposure light source. With the improvement of such fine processing by photolithography, fine workability is also required for a photomask used therein. As a resist for processing this photomask, P
BS resist [Chisso Corp., trade name], CMS resist [Tosoh Corp., trade name], electron beam resist ZEP series [Nihon Zeon Corp., trade name], etc. are used. With respect to the above, a chemically amplified resist having higher sensitivity and higher resolution is required. By the way, a large and square substrate is used for manufacturing a photomask. Unlike resist coating on circular substrates used to manufacture general semiconductor devices, coating resist on large, square substrates requires uniformity of film thickness up to the corners, Advanced technology is needed. Due to such a request, in manufacturing a photomask, a resist film forming process on a substrate and a pattern forming process may be performed by another company. In this case,
The resist flows in a state of a resist film applied to the substrate. However, the chemically amplified resist, which is being considered for application to next-generation masks, uses an acid-catalyzed reaction that occurs in the presence of a trace amount of acid. It is known that the sensitivity and the resolution are greatly deteriorated with time due to environmental contaminants during transportation. That is, it is difficult to maintain a stable resist film until the pattern forming step.

[0003]

SUMMARY OF THE INVENTION Under such circumstances, the present invention is intended to reduce the sensitivity and resolution of a chemically amplified resist film formed on a substrate over time during storage and transportation. It is an object of the present invention to provide a method for efficiently forming a chemically amplified resist pattern having a rectangular cross section and excellent in dimensional fidelity.

[0004]

Means for Solving the Problems The present inventors have studied the formation of a film on a chemically amplified resist film in order to suppress the deterioration of sensitivity, resolution and the like with time of the resist film. In addition, it has been found that it is effective to provide a film made of amorphous polyolefins (JP-A-6-9553).
No. 97). However, in this method, a coating solution formed by dissolving an amorphous polyolefin in an appropriate solvent is applied on the resist film to form a film. However, depending on the compatibility between the resist film and the film, the film is applied. There is a problem that the properties are poor and the sufficient effect may not be exhibited. Thus, the present inventors have further studied a coating film having good coatability that effectively suppresses deterioration of sensitivity and resolution over time of a chemically amplified resist film and provides a good resist pattern. The aromatic ring-containing polymer which may be substituted has good coatability, and by providing the film on the resist film, a good pattern is obtained, and furthermore, the deterioration of sensitivity and resolution when the resist film is left is suppressed. Found to be. The present invention has been completed based on such findings. That is, the present invention
(1) (A) a step of forming a chemically amplified resist film on a substrate, (B) a step of forming a film made of an aromatic ring-containing polymer which may be halogen-substituted on the chemically amplified resist film, (C) irradiating ionizing radiation to the chemically amplified resist film provided with the film on the surface to perform selective exposure,
Forming a latent image pattern; and (D) developing the chemically amplified resist film having the latent image pattern to visualize the latent image pattern. 2. The method for forming a chemically amplified resist pattern according to claim 1, wherein the resist film is subjected to a heat treatment before the step (D) after the step (C) after the step (2) (C), and (3) a fragrance optionally substituted with halogen. A resist coating agent composition comprising a ring-containing polymer and a solvent,
(4) A method for manufacturing a photomask, comprising: a step of performing the method for forming a resist pattern according to (1) or (2), an etching step, and a resist pattern stripping step; and (5) a chemically amplified resist film. And a film made of an aromatic-ring-containing polymer which may be substituted with halogen, formed thereon.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The method of forming a chemically amplified resist pattern according to the present invention includes steps (A) to (D), and each step will be described below. Step (A) in the method of the present invention is a step of forming a chemically amplified resist film on a substrate. In the step (A), as the chemically amplified resist composition used for forming the resist film, either a positive type or a negative type can be used. There is no particular limitation on the chemically amplified positive resist composition, and conventionally known compositions such as a resin whose solubility in alkali changes by the action of an acid and a compound which generates an acid by irradiation with ionizing radiation are essential components. As a resist composition. Further, the chemically amplified negative resist composition is not particularly limited, and conventionally known ones, for example, an alkali-soluble resin, an acid-crosslinkable substance,
A resist composition containing, as an essential component, a compound capable of generating an acid upon irradiation with ionizing radiation can be used. In the chemically amplified positive resist composition, the resin whose solubility in alkali is changed by the action of an acid has at least a part of a group imparting alkali solubility such as a phenolic hydroxyl group or a carboxyl group in the alkali-soluble resin. It is protected by an acid-dissociable substituent and has become hardly soluble in alkali. Examples of the alkali-soluble resin include novolak resins obtained by condensing phenols such as phenol, m-cresol, p-cresol, xylenol, and trimethylphenol with aldehydes such as formaldehyde in the presence of an acidic catalyst, and hydroxystyrene. Polyhydroxystyrene resins such as homopolymers of styrene or copolymers of hydroxystyrene with other styrene monomers, copolymers of hydroxystyrene with acrylic acid or methacrylic acid or derivatives thereof, acrylic acid or methacrylic acid And an alkali-soluble resin such as an acrylic acid or methacrylic acid-based resin which is a copolymer of and a derivative thereof.

As the alkali-soluble resin having a hydroxyl group protected by an acid-dissociable substituent, a hydroxy group in which a part of a hydroxyl group of an acidic group such as a hydroxyl group or a carboxyl group in the resin is protected by an acid-dissociable substituent. Styrene homopolymer or copolymer of the hydroxystyrene and other styrene monomers, copolymer of the hydroxystyrene and acrylic acid or methacrylic acid or a derivative thereof, or a part of the hydroxyl group in the carboxyl group And acrylic acid or methacrylic acid in which is protected by an acid-dissociable substituent and a derivative thereof, and a copolymer of hydroxystyrene or hydroxystyrene in which a part of a hydroxyl group is protected by an acid-dissociable substituent. On the other hand, as the acid dissociable substituent,
For example, alkoxycarbonyl groups such as tert-butoxycarbonyl group and tert-amyloxycarbonyl group, tertiary alkyl groups such as tert-butyl group, alkoxyalkyl groups such as ethoxyethyl group and methoxypropyl group, tetrahydropyranyl group, tetrahydrofuran An acetal group such as a benzyl group, a benzyl group, a trimethylsilyl group, a 2-propenyl group having two or more substituents,
A cycloalkyl group having a substituent at the 1-position such as -ethylcyclohexyl group. The protection ratio of hydroxyl groups by these acid-dissociable substituents is usually in the range of 1 to 60 mol%, preferably 5 to 50 mol% of the hydroxyl groups in the resin.

On the other hand, the compound that generates an acid upon irradiation with ionizing radiation (hereinafter, referred to as an acid generator) is not particularly limited, and may be any of conventional compounds used as an acid generator for a chemically amplified resist. Can be selected and used. Examples of such acid generators include bissulfonyldiazomethanes such as bis (p-toluenesulfonyl) diazomethane, p-toluenesulfonic acid 2-
Nitrobenzyl derivatives such as nitrobenzyl, sulfonic acid esters such as pyrogallol trimesylate, onium salts such as diphenyliodonium hexafluorophosphate, benzoin tosylate such as benzoin tosylate, 2- (4-methoxyphenyl) -4,
Examples include halogen-containing triazine compounds such as 6- (bistrichloromethyl) -1,3,5-triazine, and cyano group-containing oxime sulfonate compounds such as α- (methylsulfonyloxyimino) -phenylacetonitrile. One type of these acid generators may be used alone, or two or more types may be used in combination. The amount of the acid generator is 100% by weight of the resin whose solubility in alkali changes due to the action of the acid. Parts by weight is 0.5 to 30 parts by weight, preferably 1 to 10 parts by weight. When the amount is less than this range, image formation cannot be performed. When the amount is too large, a uniform solution is not obtained, and storage stability is reduced. Further, in the chemically amplified negative resist composition, as the alkali-soluble resin, for example, a phenol novolak type resin, a cresol novolak type resin, or a copolymer of polyhydroxystyrene and hydroxystyrene with a monomer copolymerizable therewith. Hydroxystyrene resins such as polymers can be mentioned. Examples of the hydroxystyrene resin include hydroxystyrene homopolymer, hydroxystyrene and acrylic acid derivative, acrylonitrile, methacrylic acid derivative, methacrylonitrile, styrene, α-
Methyl styrene, p-methyl styrene, o-methyl styrene, p-methoxy styrene, a copolymer with a styrene derivative such as p-chlorostyrene, a hydrogenated resin of a hydroxystyrene homopolymer, and hydroxystyrene and the above acrylic acid derivative; Examples include a hydrogenated resin of a copolymer with a methacrylic acid derivative or a styrene derivative. In addition, those obtained by protecting a part of hydroxyl groups of acidic groups such as hydroxyl group and carboxyl group in these resins with an acid dissociable substituent can also be suitably used. On the other hand, as the acid-crosslinkable substance, conventionally, as a crosslinking agent for a chemically amplified negative resist, an N-methylolated or alkoxymethylated melamine resin, an epoxy compound, a urea resin, or the like, which is commonly used, is used alone. , Or a mixture of two or more.

Examples of the acid generator include the same compounds as the compounds exemplified in the aforementioned chemically amplified positive resist composition. About the compounding ratio of each component, with respect to 100 parts by weight of the alkali-soluble resin, usually,
It is selected in the range of 3 to 70 parts by weight of the acid crosslinking substance and 0.5 to 20 parts by weight of the acid generator. When the amount of the acid crosslinkable substance is less than 3 parts by weight, a resist pattern is hardly formed, and when the amount exceeds 70 parts by weight, the developability is reduced. If the amount of the acid generator is less than 0.5 part by weight, the sensitivity is lowered,
If the amount exceeds 0 parts by weight, it is difficult to obtain a uniform resist, and the developability also decreases. These resist compositions are usually used in the form of a solution obtained by dissolving the above components in a solvent. Examples of the solvent include ketones such as acetone, methyl ethyl ketone, cyclohexanenone, methyl isoamyl ketone, and 2-heptanone; ethylene glycol, ethylene glycol monoacetate, diethylene glycol, diethylene glycol monoacetate, propylene glycol, propylene glycol monoacetate, and dipropylene. Glycol or dipropylene glycol monoacetate, or polyhydric alcohols such as monomethyl ether, monoethyl ether, monopropyl ether, monobutyl ether or monophenyl ether and derivatives thereof; cyclic ethers such as dioxane; and methyl lactate , Ethyl lactate, methyl acetate, ethyl acetate, butyl acetate, methyl pyruvate, ethyl pyruvate, methoxyprop Methyl phosphate, esters such as ethyl ethoxypropionate, N, N-dimethylformamide, N,
Amide-based solvents such as N-dimethylacetamide and N-methyl-2-pyrrolidone can be exemplified. These may be used alone or as a mixture of two or more.

The solution of the resist composition thus prepared may further contain, if desired, a miscible additive,
For example, additional resins, organic amines, organic carboxylic acids, and the like to improve the performance, sensitivity, and resolution of the resist film,
Further, commonly used substances such as a plasticizer, a stabilizer, a surfactant and an antioxidant can be contained. The substrate used in the step (A) is not particularly limited, and various substrates are used depending on the application. For example, a silicon wafer for a semiconductor device, a blank for a photomask, and the like can be given. The shape is not particularly limited, and may be any of a circular shape (for example, a silicon wafer) and a square shape (for example, a photomask blank). A solution of the above-described chemically amplified resist composition is applied to these substrates, and a heat treatment is performed to form a chemically amplified resist film. As a coating method, spin coating is generally preferably used. The heat treatment is performed to dry and remove the solvent. The heating temperature is usually about 60 to 160 ° C., and the heating time is about 1 to 30 minutes. The thickness of the resist film thus formed varies depending on the application, but is usually selected in the range of 10 to 1000 nm. In the case of manufacturing a photomask, the thickness is generally about 100 to 400 nm. The step (B) in the method of the present invention comprises, on the chemically amplified resist film thus formed on the substrate,
This is a step of forming a film made of an aromatic ring-containing polymer that may be substituted with halogen (hereinafter, may be simply referred to as an aromatic ring-containing polymer).

The film is provided to block the atmosphere between the chemically amplified resist film and the atmosphere. (1) The film has high transparency with respect to an exposure wavelength and transmits a particle beam such as an electron beam. Excellent coatability and film forming ability,
(3) do not transmit impurities contained in the atmosphere;
(4) It has properties such as being chemically stable.
Examples of the aromatic ring-containing polymer which may be substituted with halogen include polystyrene, poly-2-methylstyrene, poly-3-methylstyrene, poly-4-methylstyrene, poly-2-methoxystyrene, and poly-3. -Methoxystyrene, poly-4-methoxystyrene, poly-2-
Chlorostyrene, poly-3-chlorostyrene, poly-4
-Chlorostyrene, poly-2-bromostyrene, poly-
Aromatic vinyl compound polymers such as 3-bromostyrene, poly-4-bromostyrene, poly-2- (chloromethyl) styrene, poly-3- (chloromethyl) styrene, and poly-4- (chloromethyl) styrene No. In addition, phenyl acrylate, 2-methylphenyl acrylate, 3-methylphenyl acrylate, 4-
Methylphenyl acrylate, 2-methoxyphenyl acrylate, 3-methoxyphenyl acrylate, 4-methoxyphenyl acrylate, 2-chlorophenyl acrylate, 3-chlorophenyl acrylate, 4-chlorophenyl acrylate, 2-bromophenyl acrylate, 3-bromophenyl acrylate, 4 -Bromophenyl acrylate, phenyl methacrylate, 2-methylphenyl methacrylate, 3-methylphenyl methacrylate, 4-methylphenyl methacrylate, 2-chlorophenyl methacrylate, 3-chlorophenyl methacrylate,
At least one monomer selected from aromatic ester compounds of unsaturated aliphatic carboxylic acids such as 4-chlorophenyl methacrylate, 2-bromophenyl methacrylate, 3-bromophenyl methacrylate, and 4-bromophenyl methacrylate; If necessary, a polymer obtained by polymerizing together with a monomer copolymerizable therewith without a solvent or in an appropriate solvent may be mentioned.
Among the above-mentioned polymers, a polymer of an aromatic vinyl compound having higher sensitivity change suppressing power is preferable.

Examples of the polymerization solvent that can be used when polymerizing the above monomers include aliphatic hydrocarbons such as hexane, cyclohexane, heptane and octane; aromatic hydrocarbons such as benzene, toluene, xylene and naphthalene; Ketones such as acetone, methyl ethyl ketone and diethyl ketone, ethers such as dimethyl ether, tetrahydrofuran, dioxane and diphenyl ether, esters such as ethyl acetate, butyl acetate and ethyl benzoate, ether esters such as ethyl cellosolve acetate and propylene glycol monomethyl ether acetate And amides such as dimethylacetamide, dimethylformamide and hexamethylphosphoric triamide. As the catalyst, azobisisobutyronitrile, dicumyl peroxide, butyl lithium,
Various polymerization initiators such as methyllithium and ethyllithium can be used. These aromatic ring-containing polymers are excellent in coatability and can be uniformly coated on a resist film with good adhesion. The aromatic ring-containing polymer is 1
The seeds may be used alone or in combination of two or more. The aromatic ring-containing polymer is dissolved in an appropriate solvent, and if necessary, filtered to prepare a coating solution, and applied to a chemically amplified resist film by spin coating or the like. By heating and drying at a temperature of about 130 ° C., a desired film is formed. It is preferable to select a solvent that does not dissolve or hardly dissolves the resist film. Examples of such a solvent include aliphatic hydrocarbons such as n-hexane, cyclohexane, n-heptane, methylcyclohexane, n-octane, isooctane, n-decane, decalin, ligroin, benzene, toluene, xylene, ethylbenzene, Examples include aromatic hydrocarbons such as isopropylbenzene and diethylbenzene, and halogenated aliphatic hydrocarbons such as carbon tetrachloride, chloroform, trichloroethane, perfluoropentane, and perfluorohexane.
These solvents may be used alone or as a mixture of two or more. Of course, ethers and esters can also be added to these solvents.
Among them, it is desirable to select one having a boiling point of 80 to 200 ° C, preferably 100 to 150 ° C, in order to obtain good coating properties. Further, the coating properties can be improved by adding various silicone-based, fluorine-based, and nonionic surfactants that can be added to the above-described resist composition. The amount of the surfactant is usually 1 to 10
0 ppm, preferably 5 to 50 ppm.

The thickness of the film thus formed is
Usually, it is selected in the range of 1 to 400 nm, preferably 2 to 200 nm. Especially when used for electron beam lithography, it is desirable that the thickness of the film is thinner than the thickness of the resist film,
Preferably 90% or less of the resist film, more preferably 8%
0% or less. Step (C) in the method of the present invention is to perform selective exposure or drawing by irradiating ionizing radiation to the chemically amplified resist film having the film provided on the surface in this manner,
This is a step of forming a latent image pattern. In this step, as the ionizing radiation used, for example, ultraviolet rays, g
Line, i-line, KrF excimer laser light, ArF excimer laser light, and a particle beam such as an electron beam. There is no particular limitation on the method of performing selective exposure or drawing by irradiating with ionizing radiation, and a conventionally known method can be used. For example, a method of irradiating ultraviolet rays, g-rays, i-rays, KrF excimer laser light, ArF excimer laser light, or the like through a desired mask pattern with a reduction projection exposure apparatus or the like, or a method of drawing with a particle beam such as an electron beam Can be used. In particular, drawing using a particle beam is preferable in that a good pattern shape is provided. Thus, a latent image pattern is formed on the resist film. In the step (C), if the next step (C ′) is not performed, an operation of heating the resist film at a temperature of about 60 to 130 ° C. for about 1 to 2 minutes is usually performed. When performing the step (C ′), it is preferable that the heat treatment be performed after the step (C ′), as described later. In the present invention, the step (C) may be carried out immediately after the step (B) is carried out, or may be carried out, if necessary, after leaving it for an appropriate period, for example, several months. Good.

In the method of the present invention, if the film formed on the resist film is not dissolved and removed by the developing solution in the developing process of the following step (D), the latent image is formed in the step (C) as the step (C ′). A step of removing the film made of the aromatic ring-containing polymer on the resist film on which the image pattern has been formed can be included. If the film is dissolved and removed in the developing treatment of the step (D), it is not necessary to provide the step (C ′). In this step (C ′), as a method for removing the film, a spin peeling method using a solvent can be used. At this time, as the solvent, the aforementioned (B)
In the description of preparing the coating solution of the aromatic ring-containing polymer in the step, the same solvents as those exemplified as the solvent can be exemplified. One kind of the peeling solvent may be used alone, or two or more kinds may be used in combination. After removing the film in this way, the resist film is
It is preferable to perform an operation of heating at a temperature of about 130 ° C. for about 1 to 2 minutes. In the step (D) in the method of the present invention, the chemically amplified resist film having the latent image pattern after the step (C) or the step (C ′) is developed to develop the latent image pattern into a visible image. This is the step of performing The development processing method in this step is not particularly limited, and a conventionally known method can be used. For example, 1 to 10% by weight
Development processing is performed using an alkaline aqueous solution such as an aqueous solution of tetramethylammonium hydroxide. After the development processing, a rinsing processing using usually pure water or the like is performed. In this manner, a resist pattern having a rectangular cross section and excellent dimensional fidelity can be obtained. In the present invention, further, using the obtained resist pattern as a mask, the base film is formed of a fluorine-based gas such as CF ₄ or Cl ₂ / O _2.
After performing dry etching using a chlorine-based gas such as, or wet etching using a serine ammonium nitrate aqueous solution, a photomask is manufactured by stripping the resist pattern using a resist stripping solution.
During the process, pellicle coating may be performed to prevent scratches on the photomask surface.

[0014]

Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. Example 1 As a chemically amplified positive resist, 100 parts by weight of polyhydroxystyrene having a weight average molecular weight of 5,400 in which 25 mol% of hydroxyl groups were protected by a tert-butoxycarbonyl group, 5 parts by weight of triphenylsulfonium triflate, tributylamine A composition comprising 0.09 parts by weight and 1000 parts by weight of propylene glycol monomethyl ether acetate was used. The above chemically amplified positive resist was spin-coated on a disk-shaped silicon substrate having a diameter of 10 cm, and then heat-treated at 95 ° C. for 110 seconds to form a resist film having a thickness of 400 nm. Separately, a styrene polymer [degree of polymerization: about 3,000, manufactured by Wako Pure Chemical Industries]
Is a 4% by weight xylene solution, and the surfactant KP
-341 [manufactured by Shin-Etsu Silicone Co., Ltd.] was added to a concentration of 25 ppm. This was filtered through a PTFE membrane filter having a pore size of 0.2 μm to prepare a xylene solution of polystyrene. Next, a xylene solution of polystyrene is spin-coated on the resist film, and then heat-treated (prebaked) at 60 ° C. for 80 seconds to have a thickness of 100 nm.
Was formed. After leaving the film for 1 minute in an environment with an ammonia concentration of 50 ppb, an electron beam lithography apparatus [ELION-X, trade name "ELS-330"
0 ”], and after drawing 20 25 μm square patterns from 2.0 μC / cm ² to 2.95 μC / cm ^{2 in} increments of 0.05 μC / cm ² , spin-peeling treatment with xylene for 15 seconds was performed. This was followed by a heat treatment (post bake) at 90 ° C. for 110 seconds on a hot plate. Next, after developing with a 2.38% by weight aqueous solution of tetramethylammonium hydroxide for 90 seconds, rinsing with pure water for 10 seconds was performed. The dose at which the resist film completely disappeared was defined as sensitivity. In this case, a dose of 2.25 μC / cm ² corresponds to that. Examples 2 and 3 The same procedure as in Example 1 was carried out except that the standing time after the formation of the protective film was changed as shown in Table 1. The results are shown in Table 1. Comparative Example 1 In Example 1, after forming the resist film, the film was left for 1 minute in an environment of 50 ppb of ammonia without providing a protective film, and then the sensitivity was determined in the same manner. The results are shown in Table 1.

[0015]

[Table 1]

From Table 1, it can be seen that Examples 1 to 3 are all higher in sensitivity than Comparative Example 1, and that 50 ppm of ammonia is used.
b It can be seen that there is no change in sensitivity even when left for three months in an environment.

[0017]

According to the method of the present invention, the deterioration of sensitivity, resolution and the like due to aging during storage and transportation of a chemically amplified resist film formed on a substrate is suppressed, and the cross-sectional shape is rectangular. In addition, a chemically amplified resist pattern having excellent dimensional fidelity can be efficiently formed. The method of the present invention is particularly suitably applied to the manufacture of a photomask used for manufacturing a semiconductor device or the like.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) H01L 21/027 H01L 21/30 575 F term (Reference) 2H025 AA03 AA11 AB16 AC04 AC08 AD01 AD03 BE00 BE10 BG00 CB16 CB17 CB41 DA02 FA17 2H096 AA25 BA01 BA09 EA03 EA04 FA01 GA08 LA01 4J038 CC021 CC071 CC081 CC101 CG141 CH081 KA06 PB09 PB11 PC03 5F046 JA04 JA22

Claims (5)

[Claims] (A) a step of forming a chemically amplified resist film on a substrate; and (B) forming a film made of an aromatic ring-containing polymer which may be halogen-substituted on the chemically amplified resist film. (C) a step of irradiating ionizing radiation to a chemically amplified resist film having a surface provided with the film to perform selective exposure to form a latent image pattern, and (D) a chemically amplified resist film having a latent image pattern. A method for forming a chemically amplified resist pattern, comprising a step of developing a resist film to visualize the latent image pattern. 2. The method according to claim 1, wherein the resist film is subjected to a heat treatment after the step (C) and before the step (D). 3. A resist coating agent composition comprising an aromatic ring-containing polymer which may be halogen-substituted and a solvent. 4. A method for manufacturing a photomask, comprising: a step of performing the method of forming a resist pattern according to claim 1; an etching step; and a resist pattern stripping step. 5. A substrate for manufacturing a semiconductor device, comprising a chemically amplified resist film and a film formed on the aromatic ring-containing polymer which may be halogen-substituted, formed thereon.