JPH0458245A - Mask for forming fine pattern and production thereof - Google Patents

Abstract

PURPOSE:To improve quality by providing negative resist films in the parts where the light shielding films of a transparent substrate are not formed. CONSTITUTION:The production of the mask for forming fine patterns is executed by applying and forming the negative resist films 3 of 5,000Angstrom film thickness on the surface of the light shielding films 2 formed on the surface of the transparent substrate 1. The films 3 are then irradiated and exposed with light of 300 to 400nm wavelength and 20 to 30mW/cm<2> illuminance from the side of the transparent substrate 1 where the light shielding films 2 and the films 3 are not formed. The light absorptive films 3 are formed in the parts of the wide aperture patterns 2a of the light shielding films 2 when the films 3 are subjected to dip developing. The films 3 are, however, not opened in the parts of the narrow aperture patterns 2b and, therefore, the negative resist films 3 are removed by the development processing and nothing is left therein. The mask is then used for a 5:1 reduction stepper and the positive resist film 6 formed on the surface of a material to be exposed, for example, a semiconductor wafer 5, is exposed by the g ray single wavelength light at 40 to 50mj/cm intensity and is developed by an aq. soln. of 2.38% TMAH, by which the positive resist film 6 is patterned.

Description

Detailed Description of the Invention [Summary] In a mask for fine pattern formation having an open pattern of a light shielding film with different dimensions, the present invention relates to an improvement in making the amount of light transmitted through the open pattern uniform. The purpose of the present invention is to provide a mask for forming a fine pattern and a method for manufacturing the same, which makes it possible to uniformly expose a resist film formed on the surface of an object to light in one exposure even when the dimensions of the pattern are different. [1] ]A transparent substrate that transmits visible light or ultraviolet rays,
In the pattern forming mask in which a light shielding film that does not transmit visible light or ultraviolet rays is formed, a negative resist film is provided on a portion of the transparent substrate where the light shielding film is not formed.

[2] The method for manufacturing a mask for forming a fine pattern according to claim 1, comprising: applying a negative resist film to the surface of the light shielding film formed on the transparent substrate; A step of irradiating the entire surface with a light beam of a wavelength to which the negative resist film is sensitive from a surface on which no resist film is formed, and developing the negative resist a to selectively expose only the resist film in the areas where the distance between the light shielding films is wide. and selectively removing only the portions of the resist film where the spacing between the light shielding films is narrow.

[Industrial application field]

The present invention relates to an improvement in a fine pattern forming mask having open patterns of light-shielding films having different dimensions, in which the amount of light passing through the open patterns is made equal.

2. Description of the Related Art In the photolithography process of recent semiconductor device manufacturing processes, a technique for forming fine patterns with accurate dimensions is required.

When open patterns with different dimensions are formed on the same mask, and when exposing a resist film formed on the surface of an object to exposure in a single exposure, if the open pattern is narrow, the surface of the resist film will be Since the intensity of the imaging light becomes extremely weak, if the optimum exposure amount for the resist film is set to the amount of light that passes through a wide aperture pattern, the amount of light that passes through a narrow aperture pattern will be insufficient and the resist film will not be exposed (or vice versa). If the amount of light transmitted through a narrow open pattern is set as the optimum exposure amount for the resist film, the amount of light transmitted through a wide open pattern becomes excessive, and the dimension of the resist film exposed to light becomes too large.

In order to prevent such problems, it is necessary to improve the resolution of the projection exposure equipment and the resolution characteristics of the resist formed on the exposed object. When exposing a resist film formed on the surface of an object to be exposed by -degree exposure, open patterns with different dimensions are formed.
There is a need for a mask for forming a fine pattern and a method for manufacturing the same, which allows the amount of light that passes through a wide open pattern to be approximately equal to the amount of light that passes through a narrow open pattern.

[Conventional technology]

A conventional mask for forming fine patterns will be explained in detail with reference to FIG.

As shown in FIG. 4, a conventional mask for forming fine patterns has a light-shielding film 12 formed on the surface of a transparent substrate 11 with open patterns having different dimensions.

Light shielding film 1 having open patterns with different dimensions as described above
When the resist film formed on the surface of the object to be exposed is exposed to light using the fine pattern forming mask on which No. 2 is formed, the amount of light that passes through the wide open pattern is set as the optimum exposure amount for the resist film. The amount of light that passes through the narrow open pattern is insufficient and the resist film is not exposed. Conversely, if the amount of light that passes through the narrow open pattern is set as the optimum exposure amount for the resist film, the amount of light that passes through the wide open pattern becomes excessive and the resist film is damaged. The exposed dimensions become too large.

In order to prevent such problems, efforts have been made to improve the resolution of projection exposure equipment and the resolution characteristics of the resist formed on the exposed object, but both have reached their limits.
It has become difficult to control the dimensions of a pattern formed on a resist film on the surface of an exposed object.

[Problem to be solved by the invention]

In the conventional fine pattern forming mask described above, a resist film is formed on the surface of the exposed object by -degree exposure using a fine pattern forming mask on which a light shielding film having open patterns with different dimensions is formed. When exposing the resist film, if the amount of light that passes through the wide aperture pattern is set as the optimum exposure amount for the resist film, the amount of light that passes through the narrow aperture pattern will be insufficient and the resist film will not be exposed. If the amount of light is set to the optimum exposure amount for the resist film, the amount of light transmitted through the wide open pattern becomes excessive, and there is a problem in that the dimension of the resist film exposed to light becomes too large due to light diffraction.

Due to the above-mentioned circumstances, the uninvented invention makes it possible to uniformly expose the resist film formed on the surface of the object to be exposed by one exposure even if the dimensions of the open patterns of the light-shielding film formed on the transparent substrate are different. The purpose of this paper is to clarify the fine pattern forming mask and its manufacturing method.

[Means to solve the problem]

The fine pattern forming mask of the present invention is a pattern forming mask in which a light shielding film that does not transmit visible light or ultraviolet rays is formed on a transparent substrate that transmits visible light or ultraviolet rays, in which the light shielding film of the transparent substrate is formed. The method for manufacturing a mask for forming a fine pattern of the present invention includes the steps of: applying a negative resist film on the surface of the light shielding film formed on the transparent substrate; A step of irradiating the entire surface of the transparent substrate with a light beam having a wavelength to which the negative resist film is sensitive from a surface on which the light shielding film and the negative resist film are not formed, and developing the negative resist film so that the distance between the light shielding films is wide. The method is configured to include a step of selectively leaving only a portion of the resist film, and selectively removing only a portion of the resist film where the distance between the light shielding films is narrow.

[Effect]

That is, in the present invention, a light-absorbing negative resist film is formed on the wide open pattern of the light shielding film formed on the transparent substrate, and no negative resist film is formed on the narrow open pattern, so that the amount of light transmitted through the narrow open pattern is reduced. Even if this is the optimum exposure amount for the resist film formed on the surface of the exposed object, in a wide open pattern, the light is absorbed by this light-absorbing negative resist film and the amount of light decreases, and no diffraction of light rays occurs. The resist film is exposed evenly in both the wide open pattern and the narrow open pattern, making it possible to form a fine pattern with accurate dimensions.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS A fine pattern forming mask and a manufacturing method thereof according to an embodiment of the present invention will be explained in detail below with reference to FIGS. 1 to 3.

FIG. 1 is a side sectional view showing a mask for forming a fine pattern according to an embodiment of the present invention, in which the surface of a transparent substrate 1 made of quartz with a thickness of 3 to 4 cm is coated with a film of chromium and chromium oxide. A light shielding film 2 for 600 people is formed, and a wide opening pattern 2a and a narrow opening pattern 2b form the light shielding film 2.
is formed between.

Although nothing is formed on the narrow opening pattern 2b, a light-absorbing negative resist 113 is formed on the wide opening pattern 2a.

A method of manufacturing a mask for forming a fine pattern according to an embodiment of the present invention will be explained in the order of steps with reference to FIG.

First, as shown in FIG. 2(a), a 5,000-thickness negative resist [3] is applied to the surface of a light-shielding film 2 formed on the surface of a transparent substrate l.

Next, as shown in FIG. 2(b), a wavelength of 300 to 400 nm and a brightness of 20 to 30 mW/cd are applied to the negative resist film 3 from the side of the transparent substrate 1 on which the light shielding film 2 and the negative resist film 3 are not formed. When the negative resist film 3 is immersed and developed after being irradiated with light of Since the negative resist film 3 is not exposed to light in some areas, the negative resist film 3 is removed by the development process and nothing remains.

The mask manufactured in this way is used in a 5:l reduction projection exposure apparatus, and a positive resist film 6 is formed on the surface of an object to be exposed, for example, a semiconductor wafer 5, as shown in FIG. 3 using G-line single wavelength light. Exposure at an intensity of 40-50mJ10f,
The positive resist film 6 is patterned by developing with a 38% AH2 aqueous solution.

In the mask of the present invention, the light that passes through the wide opening pattern 2a is absorbed by the negative resist film 3.
Even if the narrow aperture pattern 2b is exposed with the optimal exposure amount, the pattern formed on the positive resist film 6 formed on the semiconductor wafer 5 by the light transmitted through the wide aperture pattern 2a and converged by the projection lens 4 will be affected by the light. It is possible to prevent the size from increasing due to diffraction.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, a negative resist film with an extremely simple structure is provided on the wide open pattern of the light shielding film, so even if the optimum light amount is exposed for the narrow open pattern, the wide open pattern cannot be exposed. It has the advantage that light diffraction does not occur and it is possible to pattern the resist film with accurate dimensions of wide open pattern and narrow open pattern with -degree exposure, and it is expected to have a significant quality improvement effect. It is possible to provide a mask for forming fine patterns and a method for manufacturing the same.

[Brief explanation of drawings]

FIG. 1 is a sectional side view showing a mask for forming a fine pattern according to an embodiment of the present invention; FIG. 2 is a sectional side view showing a method for manufacturing a mask for forming a fine pattern according to an embodiment of the present invention in order of steps; FIG. 3 is a diagram showing a state in which projection exposure is performed using a mask for forming a fine pattern according to an embodiment of the present invention, and FIG. 4 is a side sectional view showing a conventional mask for forming a fine pattern. In the figure, 2 is a transparent substrate, 2 is a light-shielding film, 2a is a wide open pattern, 2b is a narrow open pattern, 3 is a negative resist film, 4 is a projection lens, 5 is a semiconductor wafer, and 6 is a positive resist film. Flea according to the present invention - Side cross section of the National Army 1 showing the mask for forming fine patterns according to the embodiment Tal ill light film (2) and negative resist film (3)
Formation of tJ43 (Fig. yama) Exposure of negative resist l1l (3) and me side cross-sectional view showing the manufacturing method of a mask for forming a fine pattern according to an embodiment of the present invention in the order of steps Fig. 182 Side showing a conventional mask for forming a fine pattern Cross-sectional view Figure 4

Claims (1)

[Scope of Claims] [1] A transparent substrate (1) that transmits visible light or ultraviolet rays;
), a pattern forming mask in which a light shielding film (2) that does not transmit visible light or ultraviolet rays is formed, a negative resist film ( 3) A mask for forming a fine pattern, characterized by comprising: [2] The method for manufacturing a mask for forming a fine pattern according to claim 1, comprising the step of applying a negative resist film (3) on the surface of the light shielding film (2) formed on the transparent substrate (1). , irradiating the entire surface of the transparent substrate (1) with a light beam having a wavelength to which the negative resist film (3) is sensitive, from the surface on which the light shielding film (2) and the negative resist film (3) are not formed; The resist film (3) is developed to form the light shielding film (2).
selectively leaving only the negative resist film (3) in the areas where the spacing is wide, and selectively removing only the negative resist film (3) in the areas where the spacing between the light shielding film (2) is narrow; A method for manufacturing a mask for forming a fine pattern, characterized by the following.