JP2002174899A - Film for forming resist pattern and resist pattern forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a high precision resist pattern. SOLUTION: The film for forming a resist pattern by ionizing radiation lithography has at least one upper layer on a resist layer formed on a substrate and a composition in the upper layer contains an amphiphilic polymer selected from polyvinyl alcohol, polyvinylamine, polyallylsulfonic acid, cellulose, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a resist pattern forming film for fine processing and a method of forming a resist pattern, and more particularly to a method of forming a resist pattern used in ionizing radiation lithography.

[0002]

2. Description of the Related Art In the manufacture of semiconductor devices, resist patterns are formed by photolithography using ultraviolet rays. However, in the manufacture of fine semiconductor devices or photomasks, electron beams, X-rays, etc. Lithography using ionizing radiation that causes physical and chemical changes in materials has been used. A resist pattern used in lithography using ionizing radiation, unlike a resist used in conventional photolithography, requires characteristics specific to ionizing radiation lithography.

[0003] In particular, in ionizing radiation lithography, a resist material layer is formed of a plurality of layers. For example, in lithography using an electron beam, the thickness of a resist is reduced in order to prevent a reduction in resolution due to electron scattering. However,
If the thickness of the resist is reduced, the resistance during the etching process becomes insufficient.Therefore, an electron beam resist layer is formed on the polymer organic compound layer formed on the substrate, and the pattern is formed by exposure to the electron beam. After the formation, there has been proposed a method of forming a resist pattern having a sufficient thickness by etching a lower polymer organic compound layer based on a pattern formed by an electron beam.

In addition, when irradiating with an electron beam, a charge-up phenomenon occurs in which the resist is charged, and it is inevitable that a pattern formed on the resist is displaced. It has been practiced to form a conductive film on a resist film to prevent electrification by an electron beam. Positive electron beam resists such as polymethyl methacrylate used as electron beam resists have high resolution but low sensitivity, so they should be formed from a chemically amplified resist and multiple layers of a protective film. Accordingly, high sensitivity is maintained while maintaining high resolution.

[0005] For example, the present applicant has disclosed in
No. 93, an electron beam resist formed from a plurality of layers is formed by exposing a predetermined region of a photosensitive organic film applied on a substrate which is insoluble in water in an unexposed state. In the method of forming a latent image and forming a pattern made of a photosensitive organic film by performing a development process, after forming a second organic film made of a water-soluble polymer on the photosensitive organic film applied on the substrate, A developing treatment is performed, and when the second organic film is coated, a surfactant or an organic solvent is contained in the aqueous solvent to enhance the wettability to the previously applied photosensitive organic film. This is to form a resist composed of a plurality of layers which has made good adhesion at the interface between the previously applied layer and the layer applied thereon.

[0006]

However, when a protective film or a conductive layer for preventing charge-up is formed on a chemically amplified resist layer, a layer having good adhesion to a lower layer is formed. When a surfactant or the like is contained for the purpose of performing, the surfactant or the like penetrates or diffuses into the inside of the chemically amplified resist layer, thereby adversely affecting the characteristics of the chemically amplified resist layer, and causing the resist pattern to be formed. It became clear that there were major problems in terms of accuracy, stability, and the like. SUMMARY OF THE INVENTION It is an object of the present invention to form a resist layer that can be formed without adversely affecting a previously formed layer in an electron beam resist formed of a plurality of layers.

[0007]

According to the present invention, there is provided a resist pattern forming film for use in ionizing radiation lithography, wherein at least one upper layer is formed on a resist layer formed on a substrate. This is a resist pattern forming film containing an amphiphilic polymer. The upper layer is the above-described resist pattern forming film, which is a layer having at least one of a photosensitive layer, a conductive layer, a protective layer, and an antireflection film. In the method of forming a resist pattern, on the resist layer formed on the substrate, after forming an upper layer using an upper layer forming composition containing an amphiphilic polymer, the resist pattern is exposed and developed by ionizing radiation lithography to form a resist pattern. This is a method for forming a resist pattern to be formed. The upper layer is a photosensitive layer, a conductive layer, a protective layer,
The method for forming a resist pattern is a layer having at least one function of an antireflection film.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION According to the present invention, in forming a resist pattern used for forming a fine pattern, an amphiphilic polymer compound comprising a hydrophilic group and a hydrophobic group is used for forming a second layer. The mixing prevents the layer formed as the first layer from being affected by the application of the second layer.

In the conventional formation of a resist pattern, a surfactant or an organic solvent is contained in an aqueous solvent when a second organic substance film is applied. In particular, the addition of a surfactant had a great effect to make the coating of the second organic film uniform. The hydrophilic groups of the surfactant used together with the aqueous solvent include -COOH, -SiOH , -COOR, -OC
OR, -NH _3, -NH ₄ ^+, and examples of the organic solvent, ethyl alcohol, methyl alcohol, isopropyl alcohol, butyl alcohol, dimethyl ethanol amine, acetone was used. However, since these surfactants diffuse and penetrate into the already applied first layer, it is inevitable that they adversely affect the properties of the first layer.

For example, in a chemically amplified resist, if an acid is present in the resist, the reaction is accelerated, and if a base is present, the generated acid is deactivated. A commonly used surfactant plays a role of an acid or a base, and the influence of the surfactant on a chemically amplified resist cannot be avoided. Therefore, in the present invention, in the application of the second layer, by mixing an amphiphilic polymer that performs the same action as a surfactant, the application characteristics of the second layer requiring an aqueous solvent are improved, and This is to prevent the influence on the chemically amplified resist by infiltration into the first layer formed earlier.

Examples of the amphiphilic polymer that can be used in the present invention include polyvinyl alcohol, cellulose, polyamylamine, polyvinylamine, and polyvinyl sulfonic acid having the following structure.

[0012]

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The amphiphilic polymer of the present invention preferably has a weight average molecular weight of 1,000 to 200,000, more preferably 5,000 to 50,000. The amphiphilic polymer is used in an amount of 1 to 100 parts by weight of the coating composition.
It is preferably 0 to 50 parts by weight.

[0014]

The present invention will be described below with reference to examples. Example 1 A chemically amplified positive resist (RE515CP manufactured by Hitachi Chemical Co., Ltd.) was applied on a photomask substrate, and a first layer having a thickness of 500 nm after drying was formed. Next, a polyethynylalkanesulfonic acid-containing conductive polymer material (ESA manufactured by Showa Denko KK) was formed on the first layer as a conductive layer forming composition.
1 part by weight of polyvinyl sulfonic acid having a weight average molecular weight of 1,000, 2,000 and 10,000 was mixed and applied to 100 parts by weight of PACER100) to form a second layer having a thickness of 50 nm after drying. After exposure with an electron beam, develop with a tetramethylammonium developer,
The amount of reduction in the resist film was measured and evaluated using an optical interference film thickness meter (Lambda Ace manufactured by Dainippon Screen), and the evaluation results are shown in Table 1.

Comparative Example 1 Evaluation was made in the same manner as in Example 1 except that polyvinyl sulfonic acid was not added to the coating composition for the second layer. The evaluation results are shown in Table 1.

[0016]

[Table 1] Sulfonic acid molecular weight Remaining film amount of resist film (%) Example 1 1000 80 2000 90 10000 100 Comparative Example 1 No addition 100

[0017]

According to the method for forming a resist pattern of the present invention, an organic solvent or a surfactant is used as a coating composition for forming an upper layer when a resist pattern is formed using a resist formed of a plurality of layers. Instead, since a specific substance is used, it is possible to form a resist pattern with good pattern accuracy and good stability. And
A high-precision resist pattern can be manufactured also in the production of a light-shielding pattern made of a metal thin film of chromium or the like in the photomask described above, the production of a pattern in a phase shift photomask, the formation of a resist pattern on a semiconductor substrate, and the like.

Continued on the front page F term (reference) 2H025 AA01 AA02 AA09 AA19 AB16 AC05 AC06 AD03 BE00 BE10 BG00 CB04 CB07 CB41 CB42 CB45 CB51 DA02 DA11 DA34 DA38 2H097 CA16 LA10 5F056 DA02 DA08 DA30

Claims (4)

[Claims] 1. A film for forming a resist pattern by ionizing radiation lithography, wherein a resist layer formed on a substrate has at least one upper layer, and the composition in the upper layer contains an amphiphilic polymer. Characteristic film for resist pattern formation. 2. The method according to claim 1, wherein the upper layer is a photosensitive layer, a conductive layer, a protective layer,
The resist pattern forming film according to claim 1, wherein the film has at least one function of an antireflection layer. 3. A method for forming a resist pattern, comprising:
On the resist layer formed on the substrate, after forming an upper layer using an upper layer forming composition containing an amphiphilic polymer, forming a resist pattern by exposure and development by ionizing radiation lithography A method of forming a resist pattern. 4. The method according to claim 1, wherein the upper layer is a photosensitive layer, a conductive layer, a protective layer,
4. The method for forming a resist pattern according to claim 3, wherein the layer has at least one function of an antireflection layer.