TW201321907A - Method for treating resist pattern and method for producing resist pattern using thereof, and composition for forming cover layer used in the same - Google Patents

Abstract

The present invention provides a method for treating resist pattern which can improve heat resistance of the resist pattern, and a method for producing resist pattern using thereof. A method for treating developed resist pattern, which comprises: subjecting the surface of developed resist pattern to plasma treatment in an oxygen atmosphere, and contacting the surface of the resist pattern with a composition for forming cover layer comprising polymer, and the polymer contains crosslinking groups including oxazoline skeleton and etc.

Description

Surface treatment method of photoresist pattern, and photoresist pattern forming method using same Method and composition for forming a coating layer therefor

The present invention relates to a surface treatment method for a developed photoresist pattern, a method for forming a photoresist pattern using the same, and a composition for forming a coating layer used therefor.

In a wide range of fields, such as the manufacture of a semiconductor integrated circuit such as an LSI or a display surface of an FPD, and the production of a circuit board such as a color filter or a thermal head, in order to form or finely process a fine element, The light lithography technology has always been utilized. Generally, a photoresist pattern formed by photolithography is used as an etching mask or the like, and heat resistance is required.

That is, the plating process is performed by using the photoresist pattern as a mask, and the plated pattern is applied to the surface of the substrate, or the metal pattern is formed by using the photoresist pattern as a mask, and the metal wiring is formed on the surface of the substrate. In some cases, the temperature of the photoresist pattern may increase. Generally, the temperature of the photoresist pattern in these processes may be greater than 100 ° C depending on the case, but when the general photoresist is subjected to such a high temperature, the shape of the photoresist pattern may not be maintained. Such deformation of the photoresist pattern due to heat is referred to as "thermal relaxation." If the shape of the resist pattern cannot be maintained, the unevenness of the line width or the unevenness of the shape of the transfer process performed by using the photoresist pattern as a mask may cause an adverse effect on the characteristics of the device.

In order to prevent such a phenomenon, attempts have been made to treat the developed photoresist surface to improve heat resistance. For example, someone has studied when forming In the photoresist pattern, a polymer containing a crosslinkable group is added to the photoresist composition, a crosslinkable group is added to the photoresist resin itself, and a light-transmitting agent or a hardener is added to the photoresist composition. Improvement of the resist composition (Patent Documents 1 to 4). In addition, research has been conducted on a method in which a photoresist composition contains two kinds of photosensitive components, and a photoresist pattern formed using the first photosensitive component is further hardened by the second photosensitive component; curing is performed by heating while irradiating A method of curing by ultraviolet rays; a method of forming a multilayer structure by a photoresist, thereby improving heat resistance (Patent Documents 5 to 7).

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2007-233395

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2007-256943

[Patent Document 3] Japanese Patent Laid-Open Publication No. 2010-020291

[Patent Document 4] Japanese Patent Laid-Open No. Hei 6-043637

[Patent Document 5] Japanese Patent Laid-Open No. Hei 11-352702

[Patent Document 6] Japanese Patent Laid-Open No. Hei 6-186755

[Patent Document 7] Japanese Patent Laid-Open Publication No. 2002-064054

However, all of the methods have problems such as complicating the manufacturing steps, lowering the resolution of the photoresist due to the added components, and further improving the heat resistance.

The surface treatment method of the developed photoresist pattern of the present invention is characterized by comprising the following: Performing a plasma treatment on the surface of the developed photoresist pattern in an oxygen-containing gas atmosphere, and contacting the surface of the photoresist pattern with a coating layer forming composition comprising a polymer and a solvent, wherein the polymer has A crosslinkable group bonded to a functional group present on the surface of the photoresist pattern to bond.

Moreover, the pattern forming method of the present invention comprises the steps of: coating a photoresist composition on a substrate to form a photoresist composition layer, exposing the photoresist composition layer, and forming a photoresist for exposure. The material layer is developed by a developing solution to form a photoresist pattern, and the surface of the photoresist pattern is subjected to a plasma treatment in an oxygen-containing gas atmosphere, and then the surface of the photoresist pattern and a coating layer containing a polymer and a solvent are formed. Contact is carried out with a composition in which the polymer has a crosslinkable group which is bondable with a functional group present on the surface of the photoresist pattern.

Further, the coating layer forming composition of the present invention is used for forming a coating layer which forms a heat-resistant coating layer on the surface of the resist pattern in contact with the surface of the developed photoresist pattern which is subjected to plasma treatment in an oxygen-containing gas atmosphere. A composition comprising a polymer and a solvent, wherein the polymer has a crosslinkable group which is bondable with a functional group present on the surface of the photoresist pattern.

According to the method of the present invention, the heat resistance of the photoresist pattern can be improved, whereby the plating resistance or the metal deposition resistance of the photoresist pattern can be improved. Furthermore, Since the plating resistance is improved and the photoresist is eluted into the plating treatment liquid, the storage period of the plating treatment liquid can be extended.

Hereinafter, embodiments of the present invention will be described in detail.

Surface treatment method of photoresist pattern

The surface treatment method of the photoresist pattern of the present invention firstly performs a plasma treatment on the developed photoresist pattern in an oxygen-containing gas atmosphere. Here, the photoresist pattern to be subjected to the surface treatment is not particularly limited, and those formed by any method can be used (details will be described later).

Plasma treatment refers to the state of the plasma caused by electrical discharge and the reaction of the resulting reactive electrons or ions with the target. In the present invention, the plasma treatment is carried out in an oxygen-containing gas atmosphere.

As a plasma generating device for performing such plasma treatment, in addition to the low-pressure high-frequency plasma generating device, a device that can generate an atmospheric pressure discharge plasma such as oxygen plasma can be used.

In addition, the gaseous environment at the time of discharge must contain oxygen. Specifically, the gas atmosphere preferably contains 10 mol% or more of oxygen, more preferably 50 mol% or more. Since oxygen is consumed by plasma treatment, oxygen can also be injected into the gas environment. In this case, the oxygen flow rate is generally preferably from 1 to 1,000 sccm, more preferably from 10 to 200 sccm. The gas atmosphere may contain a gas other than oxygen, but the content of the gas which impedes the improvement of the hydrophilicity of the photoresist surface by the plasma treatment is preferably as small as possible.

The pressure of the gas atmosphere at the time of discharge is preferably from 1 to 1,000 Pa, more preferably from 5 to 500 Pa. At the time of discharge, the temperature of the substrate is preferably -80 to 100 ° C, more preferably -20 to 60 ° C.

The output power of the antenna at the time of discharge is preferably 10 to 5,000 W, more preferably 100 to 2,000 W.

Such plasma treatment can be performed by, for example, an NE-5000 type plasma etching apparatus (trade name, manufactured by ULVAC Co., Ltd.).

It is considered that by performing such a plasma treatment, the surface of the photoresist pattern is modified, and the functional groups present on the surface, especially the carboxyl group (-COOH) or the hydroxyl group (-OH), are increased in density. As a result, the hydrophilicity of the surface is improved, and it is considered that the reaction with a polymer containing a crosslinkable group (hereinafter simply referred to as "polymer") can be promoted. That is, by bringing the surface of the resist pattern into contact with the polymer containing a crosslinkable group, the functional group present on the surface of the resist pattern reacts with the crosslinkable group contained in the polymer to form a surface of the resist pattern. Covered layer. The coating layer functions as a "heat-resistant film which is called "thermal relaxation" when the photoresist pattern is prevented from being heated" and "a protective film which prevents the photoresist from being eluted from the plating solution when the surface is subjected to a plating treatment" .

The photoresist pattern after the plasma treatment is applied, followed by contact with a composition for forming a coating layer containing a polymer and a solvent. Here, the crosslinkable group means a group which can be bonded to a functional group existing on the surface of the resist pattern to bond. Moreover, the functional groups present on the surface of the photoresist pattern can be generated or increased by plasma treatment. However, in general, the carboxyl group or the hydroxyl group is increased by the plasma treatment, and therefore the crosslinkable group is preferably a group which can react with a carboxyl group or a hydroxyl group.

Since most of the basic groups can react with the carboxyl group, a basic group can be exemplified as the crosslinkable group which can react with the carboxyl group. More specifically, it is preferably included a crosslinkable group of an oxazoline skeleton, a pyrrolidone skeleton, a diallylamine skeleton or an amine group, more preferably included An oxazoline skeleton. On the other hand, the hydroxyl group has high reactivity with an epoxy group, an oxypropylene group or an isocyanate group, and it is preferred to contain such a crosslinking group. These crosslinkable groups may be present in the side chain of the polymer or may be present in the main chain.

When the crosslinkable group is present in the side chain of the polymer, the polymer backbone may be any. For example, any structure such as a polyethylene structure, a polyester structure, a polyamine structure, a polydecane structure, or a polyoxymethane structure may be employed. also, An oxazoline skeleton or a cyclic amine or the like may also be incorporated in the main chain. As specific examples of such polymers, the following can be cited:

Here, n represents the number of degrees of polymerization.

Further, the polymer is not limited thereto, and for example, hydrogen of the polymer exemplified herein may be substituted with an alkyl group having a carbon number of about 1 to 10 or a carbon number of the alkyl group.

Among such polymers, a representative thereof can be produced by polymerizing a polymerizable monomer containing a crosslinkable group. Any polymerizable monomer may be used, but it is preferred to carry out addition polymerization by cleavage of an unsaturated bond. The reason for this is that the polymerization reaction by the addition polymerization hardly reacts with the crosslinkable group contained in the monomer. Further, such a monomer may contain an optional substituent, and in order to avoid reaction with a crosslinkable group, it is preferred to contain no acid group, and particularly preferably a carboxyl group. For example, ethylene can be cited The oxazoline, vinylpyrrolidone, vinylimidazole, allylamine, diallylamine, etc. are not limited thereto, and any substituent may be used. More specifically, a polymerizable monomer such as the following may be used:

Further, when a polymerizable monomer containing a crosslinkable group is polymerized, a copolymerizable monomer which does not contain a crosslinkable group can be used in combination to form a copolymer. As such a monomer, vinyl alcohol, an acrylate, a methacrylate, etc. are mentioned.

The molecular weight of the polymer containing such a crosslinkable group is not particularly limited, and is preferably from 500 to 1,000,000, more preferably from 1,000 to 500,000, based on the weight average molecular weight. Here, the weight average molecular weight means one measured by a gel permeation chromatography (GPC) based on polystyrene standards.

The coating layer forming composition used in the present invention is obtained by dissolving such a polymer in a solvent such as water. At this time, the concentration of the polymer in the coating composition for forming a coating layer is higher by the viewpoint that the crosslinking density formed between the polymer and the surface of the resist pattern is higher. On the other hand, if the concentration is too high, problems such as dissolution of the photoresist pattern occur. Therefore, the polymer content of the coating layer-forming composition is generally 0.05 to 20% by weight, preferably 0.1 to 10% by weight based on the total weight of the coating layer-forming composition.

Further, the coating layer forming composition used in the present invention contains water as a solvent in addition to the above polymer. As the water to be used, it is preferred to remove organic impurities, metal ions, or the like by distillation, ion exchange treatment, filter treatment, various adsorption treatments, etc., and it is particularly preferably pure water.

The composition for forming a coating layer used in the present invention may be adjusted by adjusting a pH by adding a pH adjusting agent as needed; as such a pH adjusting agent, an acid or a base may be used. These acids or bases sometimes have the effect of improving the solubility of the respective components. The acid or base to be used can be arbitrarily selected within the range not impairing the effects of the present invention, and examples thereof include hydrochloric acid, sulfuric acid, nitric acid, sulfonic acid, amines, and ammonium salts. In the present invention, in order to make the polymer contain a crosslinkable group, most of them are Alkaline. Therefore, in order to adjust the pH, it is preferred to use an acid as an additive. Here, when a carboxylic acid is used as the acid, it reacts with the crosslinkable group contained in the polymer, and is applied to the developed photoresist pattern, and also has a possibility of not reacting with the carboxyl group present on the surface of the photoresist. Therefore, it is preferred to use no carboxylic acid. Therefore, in terms of acid, it is preferred to use hydrochloric acid, sulfuric acid, nitric acid or sulfonic acid.

When the pH of the composition for forming a coating layer is adjusted by using such an acid or the like, it is preferably from 2 to 10, more preferably from 3 to 9, from the viewpoint of stability of the composition and reaction rate.

The coating layer forming composition used in the present invention may further contain a surfactant. The surfactant can be preferably used by improving the wettability of the photoresist surface produced by the composition for forming a coating layer and adjusting the surface tension to improve pattern collapse or pattern peeling. As the surfactant, a nonionic surfactant, a cationic surfactant, an anionic surfactant, an amphoteric surfactant, or the like can be used. Among these, the nonionic surfactant is preferred because it has an effect of improving the stability of the composition. These surfactants can also be used in combination of two or more types as needed. When the surfactant is used, the content thereof is preferably 0.005 to 1% by weight, and more preferably 0.01 to 0.5% by weight based on the total weight of the coating layer-forming composition.

Further, a thermal acid generator may be added to the composition for forming a coating layer. The thermal acid generator includes, for example, a volatile amine and an acid salt, and has a function of coating the composition, drying it, and volatilizing the amine by heating to increase the acid concentration on the surface of the resist pattern. When the coating layer-forming composition containing a thermal acid generator is applied to a photoresist pattern, when the carboxyl group on the surface of the photoresist is blocked by a base, the alkali generated by the heating can be used to remove the alkali. Then, the free carboxyl group and the crosslinkable group can be promoted, for example The reaction of an oxazoline group. That is, the crosslinking reaction between the surface of the resist pattern and the polymer containing a crosslinkable group can be further promoted by adding a thermal acid generator. As a specific example of such a thermal acid generator, a salt containing p-toluenesulfonic acid and triethylamine can be exemplified.

Further, as the composition for forming a coating layer, an organic solvent other than water may be used as a co-solvent. The organic solvent has the effect of adjusting the surface tension of the rinsing liquid, and sometimes improves the wettability to the resist surface. Moreover, when the solubility of the polymer used is low in water, the solubility can also be improved. The organic solvent which can be used at this time is selected from organic solvents which are soluble in water. Specific examples thereof include alcohols such as methanol, ethanol, isopropanol and tertiary butanol, glycols such as ethylene glycol and diethylene glycol, ketones such as acetone and methyl ethyl ketone, methyl acetate and acetic acid. Esters such as ethyl ester and ethyl lactate, dimethylformamide, dimethyl hydrazine, methyl cellosolve, celecoxib, butyl acesulfame, celecoxib acetate, A solvent such as alkyl cyanoacetate, propylene glycol alkyl ether, propylene glycol alkyl ether acetate, butyl carbitol, carbitol acetate, tetrahydrofuran or the like.

However, such organic solvents sometimes dissolve or denature the photoresist constituting the pattern, and therefore need to be limited to a small amount when used. Specifically, the content of the organic solvent is generally 15% or less, preferably 7% or less, based on the total weight of the composition for forming a coating layer.

The coating layer forming composition used in the present invention may further contain a bactericide, an antibacterial agent, a preservative, and/or an antifungal agent. These agents are used to prevent bacteria or fungi from multiplying in the rinse solution over time. this Examples include alcohols such as phenoxyethanol and isothiazolone. BESTCIDE (trade name), marketed by Japan's Soda Co., Ltd., is a particularly effective preservative, anti-fungal agent and fungicide. Typically, these agents do not affect the performance of the coating layer-forming composition, and the content thereof is generally 1% by weight or less, preferably less than 0.1% by weight based on the total weight of the coating layer-forming composition. Further, it is preferably 0.001% by weight or more.

The coating layer forming composition thus prepared is brought into contact with the plasma-treated resist pattern. The contact method is not particularly limited, and the resist pattern may be immersed in the coating layer forming composition, or the coating layer forming composition may be applied to the resist surface by a coating method such as spin coating, spray coating or slit coating.

The time during which the coating layer forming composition is brought into contact with the resist surface varies depending on the type or concentration of the polymer contained in the coating layer forming composition, the temperature at the time of contact, and the like, but is generally 1 to 600 seconds, preferably. It is 5~300 seconds.

The photoresist pattern can be cleaned after being in contact with the coating layer forming composition. Excess polymer remaining on the surface of the photoresist can be removed by such cleaning. If this type of cleaning is not carried out, the alkalinity of the remaining polymer will dissolve the photoresist pattern and care should be taken. The cleaning is generally carried out with water, but water containing a surfactant or an organic solvent may also be used as required.

The photoresist pattern which is cleaned after contact with the coating composition for forming a coating layer may be further heated. Through this heating, the reaction of the surface of the photoresist pattern with the polymer can be promoted, and a stronger photoresist pattern can be formed. Such The heating temperature in the heat treatment is preferably 40 to 120 ° C, more preferably 60 to 100 ° C. The heating time is also 10 to 300 seconds, preferably 30 to 120 seconds.

By treating the surface of the photoresist pattern by such a method, the heat resistance of the photoresist pattern can be improved.

Pattern forming method

Next, a method of forming the pattern of the present invention will be described. The pattern forming method of the present invention forms a photoresist pattern by photolithography, and then processes it by the surface treatment method of the photoresist pattern.

First, the photoresist composition is applied onto the surface of a substrate such as a substrate or a glass substrate which has been subjected to pretreatment by a conventional coating method such as a spin coating method to form a photoresist composition layer. The anti-reflection film may also be formed by coating under the photoresist before coating the photoresist composition. Through such an anti-reflection film, the cross-sectional shape and the exposure margin can be improved.

Any of the conventional photoresist compositions can also be used in the pattern forming method of the present invention. When a representative example of the resist composition which can be used in the pattern forming method of the present invention is exemplified, the positive type may, for example, include a quinonediazide-based sensitizer and an alkali-soluble resin, and a chemically amplified resist composition. The negative type may be, for example, a polymer compound containing a photosensitive group such as polyvinyl cinnamate, an aromatic azide compound, or an azide compound containing a cyclized rubber and a diazide compound, and the like. A diazo resin, a photopolymerizable composition containing an addition polymerizable unsaturated compound, a chemically amplified negative type resist resin composition, or the like.

Here, as a quinonediazide sensitizer used in a positive photoresist composition containing a quinonediazide-based sensitizer and an alkali-soluble resin For example, 1,2-benzopyrenediazide-4-sulfonic acid, 1,2-naphthoquinonediazide-4-sulfonic acid, 1,2-naphthoquinonediazide-5- can be exemplified. A sulfonic acid, an ester of such a sulfonic acid, or a guanamine, and the like, and examples of the alkali-soluble resin may, for example, be a phenol resin, a polyvinyl phenol, a polyvinyl alcohol, a copolymer of acrylic acid or methacrylic acid, or the like. The phenolic resin may be one or more selected from the group consisting of phenols such as phenol, o-cresol, m-cresol, p-cresol, and xylenol, and one or more kinds of aldehydes such as formaldehyde and trioxane. The resin is preferred.

Further, in the case of the chemically amplified resist composition, either of a positive type and a negative type can be used in the pattern forming method of the present invention. The chemically amplified photoresist is irradiated with radiation to generate an acid, and the chemical change caused by the action of the acid of the acid causes a change in the solubility of the radiation irradiated portion to the developer to form a pattern, and examples thereof include radiation. An acid generating compound which generates an acid upon irradiation, and an acid-sensitive group-containing resin which decomposes in the presence of an acid to form an alkali-soluble group such as a phenolic hydroxyl group or a carboxyl group, and includes an alkali-soluble resin and a crosslinking agent. Acid generator.

The photoresist composition layer formed on the substrate is pre-baked, for example, on a hot plate to remove the solvent in the photoresist composition, thereby forming a photoresist film having a thickness of generally about 0.5 to 2.5 μm. The prebaking temperature varies depending on the solvent or photoresist composition used, but is generally carried out at a temperature of from 20 to 200 ° C, preferably from about 50 to 150 ° C.

Subsequently, the photoresist film is made of a high-pressure mercury lamp, a metal halide lamp, an ultra-high pressure mercury lamp, a KrF excimer laser, an ArF excimer laser, a soft X-ray irradiation device, a cathode ray illuminator, and the like, depending on the demand. The mask is exposed.

After the exposure, and baking is performed as needed, the photoresist pattern is formed by development by, for example, paddle development. Development of the photoresist is usually carried out using an alkaline developer. As the alkaline developing solution, an aqueous solution or an aqueous solution of, for example, sodium hydroxide, tetramethylammonium hydroxide (TMAH) or the like can be used. After the development process, it is cleaned as needed.

In the pattern forming method of the present invention, the surface resisting method of the photoresist is applied to the developed photoresist pattern obtained in this manner to treat the surface of the resist pattern. The application of the surface treatment method may be followed by development of the photoresist pattern, or after temporarily storing the developed photoresist pattern or the like.

The invention is illustrated by the following examples:

Example 1

On the ruthenium substrate, a positive-type photoresist composition (AZ40XT-11D (trade name) manufactured by AZ Electronic Materials Co., Ltd.) corresponding to the i-line exposure was applied by a spin coater at 2,600 rpm, and was 125 ° C / 360 sec. The baking treatment was carried out under conditions to prepare a substrate having a photoresist film having a film thickness of 25 to 27 μm. The obtained substrate was exposed to light at 350 to 400 mJ by an i-ray exposure apparatus (MA200e type (trade name) manufactured by Suss Microtec Co., Ltd.), and heated at 105 ° C for 75 seconds. Subsequently, development was carried out for 2.3 seconds with a 2.38% TMAH aqueous solution at 23 ° C, and rinsed with deionized water to prepare a developed photoresist substrate having a line pattern. As a result of observing the line pattern obtained here by a scanning electron microscope, the cross-sectional shape was rectangular. Further, for the developed photoresist substrate, the oxygen flow rate is 100 sccm, and the antenna output power is After the oxygen plasma treatment was carried out for 20 seconds under conditions of 1000 W, the composition for forming a coating layer in which the polymer P8 was dissolved in water at a concentration of 0.5% by weight was immersed for 20 seconds, and then washed with deionized water and dried.

Next, the heat resistance of the obtained photoresist substrate was evaluated. The obtained photoresist substrate was heated at 120 ° C for 120 seconds, and the cross-sectional shape of the line pattern was observed by a scanning electron microscope. As a result, the change in the cross-sectional shape of the line pattern caused by almost no heating is maintained in a rectangular shape.

Examples 2 to 13 and Comparative Examples 1 to 4

The presence or absence of the oxygen plasma treatment, the presence or absence of the treatment of the coating layer-forming composition, the type of the polymer, the polymer concentration of the coating layer-forming composition, the presence or absence of the co-solvent, and the immersion time were repeated and Example 1 was repeated. The conditions of the change and the results obtained are shown in Table 1. Further, the structures of the polymers used are as follows, and their weight average molecular weights are shown in Table 1. Here, polyacrylic acid (PA) is conveniently described in one of the polymers containing a crosslinkable group, but it is a polymer which does not contain a crosslinkable group. Further, when a cosolvent is used, the blending ratio is such that the content of the cosolvent is 5% by weight based on the total weight of the water and the cosolvent as the main solvent.

In addition, when the heat resistance was evaluated, it was observed by an electron microscope.

The shape of the photoresist profile is classified as follows:

I: initial shape (Fig. 1 (I))

A: Almost no deformation by the initial shape I (Fig. 1(A))

B: It can be seen that the initial shape I is slightly deformed (Fig. 1 (B))

C: It can be seen that relative to the initial state I, significant deformation due to thermal relaxation (p.

1 (C))

*THF: tetrahydrofuran

Example 14 and Comparative Example 5-7

The photoresist composition was changed to a photoresist composition corresponding to KrF exposure (DX 6270P (trade name) manufactured by AZ Electronic Materials Co., Ltd.), and Example 1 (Example 14) was repeated. In addition, the presence or absence of the oxygen plasma treatment and the presence or absence of the treatment for the coating layer-forming composition were repeated, and Example 14 (Comparative Examples 4 to 6) was repeated. Further, the heating temperature at the time of heat resistance evaluation was set to 180 °C. The conditions of the change and the results obtained are shown in Table 2.

Example 15 and Comparative Examples 8 to 10

The photoresist composition was changed to a resist composition corresponding to ArF exposure (AX1120P (trade name) manufactured by AZ Electronic Materials Co., Ltd.), and Example 1 (Example 15) was repeated. In addition, the presence or absence of the oxygen plasma treatment and the presence or absence of the treatment for the coating layer forming composition were repeated, and Example 15 (Comparative Examples 8 to 10) was repeated. The conditions of the change and the results obtained are shown in Table 3.

Fig. 1 is an electron micrograph of a cross-sectional shape of a photoresist pattern of Examples and Comparative Examples of the present invention.

Claims (11)

A surface treatment method for developing a photoresist pattern, characterized in that the surface of the photoresist pattern after development is subjected to plasma treatment in an oxygen-containing gas atmosphere, and the surface of the photoresist pattern and the polymer are contained The coating layer forming composition is contacted with a solvent having a crosslinkable group capable of reacting with a functional group existing on the surface of the resist pattern to bond. The method of claim 1, wherein the plasma treatment is carried out in a gas atmosphere containing oxygen at a concentration of 10% or more. The method of claim 1 or 2, wherein the aforementioned functional group is a carboxyl group or a hydroxyl group. The method of any one of claims 1 to 3, wherein the crosslinkable group contained in the aforementioned polymer comprises An oxazoline skeleton, a pyrrolidone skeleton, a diallylamine skeleton or an amine group. The method of any one of claims 1 to 3, wherein the crosslinkable group contained in the polymer comprises an epoxy group, an oxypropylene group or an isocyanate group. The method according to any one of claims 1 to 5, wherein the coating layer forming composition contains water as a solvent. The method of claim 6, wherein the coating forming composition further contains an organic solvent as a solvent. The method according to any one of claims 1 to 7, wherein the pH of the coating composition for coating is from 2 to 10. The method according to any one of claims 1 to 8, wherein the surface of the photoresist pattern is brought into contact with the coating layer forming composition and then heated. A pattern forming method comprising the steps of: coating a photoresist composition on a substrate to form a photoresist composition layer, exposing the photoresist composition layer, and developing the exposed photoresist composition layer by exposure The liquid is developed to form a photoresist pattern, and the surface of the photoresist pattern is subjected to a plasma treatment in an oxygen-containing gas atmosphere, and then the surface of the photoresist pattern is brought into contact with a coating layer forming composition containing a polymer and a solvent. Wherein the polymer has a crosslinkable group which is bondable with a functional group present on the surface of the photoresist pattern. A composition for forming a coating layer for forming a coating layer for forming a heat-resistant coating layer on a surface of a photoresist pattern in contact with a surface of a developed photoresist pattern which is subjected to plasma treatment in an oxygen-containing gas atmosphere And a polymer comprising a polymer and a solvent, wherein the polymer has a crosslinkable group which is bondable with a functional group present on the surface of the photoresist pattern.