JPH05326503A - Forming method of line pattern - Google Patents

Abstract

PURPOSE:To enable fine line pattern, hardly formed by photolithography, to be formed easily. CONSTITUTION:After the formation of a pattern 13 on a substrate 11 in the first step, a side wall forming film 14 is formed as if covering the pattern 13 later to form a sidewall 15 out of the sidewall forming film 14 on the sidewall of the pattern 13. Next, the pattern 13 is removed in the second step. Resultantly, the remaining sidewall 15 is to become a wire pattern 16. Besides, the other step to remove the upper part only of the wire pattern 16 can be performed. Otherwise, after the formation of another sidewall outside the sidewall forming film 14, the sidewall forming film 14 is etched away and then the pattern 13 and the other sidewall are removed so as to form the title wire pattern.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a line pattern for forming a semiconductor device, and more particularly to a method for forming a line pattern having a fine line width.

[0002]

2. Description of the Related Art The width of a line pattern used in a semiconductor device is
As semiconductor devices become highly integrated, they are being downsized. Particularly in forming a transistor having a short gate length, it is required to reduce the line pattern width. As a method of forming a narrow line pattern, there is an exposure method using i-line (wavelength is 364 nm) as a method using ultraviolet light exposure. In this case, a line pattern having a width of 0.4 μm to 0.5 μm is obtained.

In the excimer laser exposure method using an excimer laser beam as an exposure light source, a line pattern having a width of about 0.30 μm can be formed. Also, a line pattern having a width of 0.25 μm to 0.3 μm can be formed by a lithography technique that combines the multilayer resist method and the excimer laser exposure method. In order to form a line pattern with a finer width (for example, 0.2 μm or less), direct writing with an electron beam must be performed.

[0004]

However, in the next-generation transistors, a gate length of about 0.1 μm is required. Therefore, it cannot be realized by the i-line exposure method, the excimer laser exposure method, the lithography technique that combines the multilayer resist method and the excimer laser exposure method, and the like. In addition, direct drawing with an electron beam takes a very long time and is not suitable for mass production technology.

An object of the present invention is to provide a method for forming a line pattern which is excellent in easily forming a line pattern having a fine width.

[0006]

The present invention is a method made to achieve the above object. That is, as the first method, in the first step, after forming the pattern on the substrate, the sidewall forming film is formed so as to cover the pattern, and then the side wall forming film portion formed on the side wall of the pattern is formed. The sidewall forming film in other portions except for is removed to form sidewalls on the sidewalls of the pattern. Then, in a second step, the line pattern is formed by removing the pattern and leaving the sidewall. Alternatively, as a second method, a step of removing the upper portion of the line pattern is performed after performing the second step.

As a third method, in the first step,
After forming the pattern on the substrate, forming the first film so as to cover the pattern, and then forming the second film on the surface of the first film, and then the side of the pattern on the side of the first film. A first sidewall is formed of the second film in the portion. Then second
In the step of, the first side wall of the pattern is removed by using the first side wall as an etching mask and removing the first film of the part other than the part of the first film between the first side wall and the pattern. Then, a second sidewall is formed of the first film. Then, in a third step, the pattern and the second sidewall are removed, leaving only the second sidewall.
Then, in a fourth step, a portion of the second sidewall covered with the first sidewall and the upper portion of the second sidewall are removed to form a line pattern.

As a fourth method, in the first step, after forming a pattern on a substrate, a first film is formed so as to cover the pattern, and then a flat surface is formed on the surface of the first film. After the formation of the second film having the pattern, the second film is removed until the height is almost the same as the pattern. Next, in a second step, the first film on the pattern is removed to expose the pattern, and in a third step, the pattern and the second film are removed. Then, in a third step, the line pattern is formed by removing the portion of the first film and the upper portion of the first film which were covered with the second film.

[0009]

In the method of forming a line pattern according to the first to third methods, the line pattern is formed by utilizing the side wall or the second side wall, so that the line pattern is formed in a self-aligned manner. Therefore, since the width of the line pattern is determined by the film thickness of the sidewall forming film or the film thickness of the first film, the line pattern is formed with a width of about 0.1 μm or less.

In the line pattern forming method according to the fourth method, the second film is removed to a height substantially equal to the pattern, so that the remaining second film is removed from the first side of the third method. Similar to a wall. Therefore,
Since the width of the line pattern is determined by the film thickness of the first film, the line pattern is formed to have a width of about 0.1 μm or less.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described with reference to the forming process diagram shown in FIG. The first step shown in (1) of FIG. 1 is performed. In this step, for example, a silicon oxide film 12 is formed as a film for forming a pattern on the substrate 11 by a normal chemical vapor deposition method. Then, the portion indicated by the chain double-dashed line of the silicon oxide film 12 is removed by ordinary photolithography and etching, and the pattern 13 is formed by the remaining silicon oxide film 12.

Thereafter, as shown in FIG. 1B, a sidewall forming film 14 made of, for example, polycrystalline silicon is formed in a state of covering the pattern 13 by, for example, an ordinary chemical vapor deposition method. Then, by a normal etch-back process, the remaining sidewall forming film 14 (the portion indicated by the chain double-dashed line) except the sidewall forming film 14 formed on the sidewall of the pattern 13 is removed, whereby the sidewall of the pattern 13 is removed. Sidewalls 15 are formed on.

Then, the second step shown in FIG. 1C is performed. In this step, the pattern 13 (the portion indicated by the chain double-dashed line) is removed by ordinary etching to leave the side wall 15, and thus the side wall 15 is removed.
The line pattern 16 is formed. The line pattern 16 formed by the above method is formed in a rectangular shape on the surface of the substrate 11. Therefore, a desired line pattern (not shown) can be obtained by removing the line pattern 16 in an unnecessary portion by usual photolithography and etching.

In the method of forming a line pattern according to the first embodiment, the line pattern 16 is formed by the side wall 15, so that the line pattern 16 is formed in a self-aligned manner.
Therefore, the width of the line pattern 16 can be determined by the film thickness of the sidewall forming film 14,
It becomes possible to form the line pattern 16 having a width of about 0.1 μm or less.

Next, a second embodiment will be described with reference to the forming process diagram shown in FIG. The same components as those described in the first embodiment are designated by the same reference numerals. After completing the steps described in the first embodiment, as shown in the figure, for example, the substrate 1
The upper portion 17 (the portion indicated by the chain double-dashed line) of the line pattern 16 is removed by anisotropic etching in which the etching proceeds in the direction perpendicular to 1.

In the above etching step, unnecessary line patterns 16 are removed by ordinary photolithography and etching to remove a desired line pattern (not shown).
It is also possible to do after obtaining.

In the method of forming a line pattern according to the second embodiment, since the upper portion 17 of the line pattern 16 is removed,
The upper part of the line pattern 16 is rounded. Therefore, when a film is formed on the line pattern 16, the formed film has good coverage.

Next, a third embodiment will be described with reference to the forming process diagram shown in FIG. The first step shown in FIG. 3A is performed. In this step, the pattern 32 is formed on the substrate 31 in the same manner as the method of forming the pattern (13) described in the first embodiment. Then, a first film 33 made of, for example, polycrystalline silicon is formed in a state of covering the pattern 32 by, for example, a normal chemical vapor deposition method. Then, the second film 34 is formed on the surface of the first film 33 by a normal chemical vapor deposition method. After that, the portion indicated by the chain double-dashed line of the second film 34 is removed by a normal etchback process, and the side wall of the first film 33 on the side wall of the pattern 32 is covered with the second film 34. The first sidewall 35 is formed.

Then, a second step shown in FIG. 3B is performed. In this step, the portion indicated by the chain double-dashed line of the first film 33 is removed by normal anisotropic etching using the first sidewall 35 as an etching mask, and the first sidewall 33 is covered with the first sidewall. A second sidewall 36 made of the film 33 is formed.

Subsequently, a third step shown in FIG. 3C is performed. In this step, the pattern 32 (the portion indicated by the two-dot chain line) and the second sidewall 36 (the portion indicated by the one-dot chain line) are removed by normal etching, and only the second sidewall 36 is removed. Leave.

Thereafter, a fourth step shown in FIG. 3 (4) is performed. In this step, the portion of the second sidewall 36 (two-dot chain line) covered by the first sidewall (35) is anisotropically etched so that the etching proceeds substantially perpendicularly to the substrate 31. Part indicated with),
The upper portion 37 of the second sidewall 36 (the portion indicated by the alternate long and short dash line) is removed. Then, the line pattern 38 is formed.

In the method of forming a line pattern according to the third embodiment, the first film 33 is etched with the first side wall 35 and the pattern 32 sandwiching the first film 33, so that the first film 33 is formed. Second side wall 3
The upper portion of 6 is rounded. Further, since the line pattern 38 is formed by anisotropically etching the second sidewall 36, the line pattern 38 is formed in a self-aligned manner. Therefore, the width of the line pattern 38 can be determined by the film thickness of the first film 33, so that the line pattern 38 having a width of about 0.1 μm or less can be formed.

The line pattern 38 formed by the above method is formed in a rectangular shape on the surface of the substrate 31. Therefore,
A desired line pattern (not shown) is obtained by removing the line pattern 38 in an unnecessary portion by usual photolithography and etching. In addition, after forming the second sidewall 36 in the third step, the unnecessary portion of the second sidewall 36 is removed, and then the fourth step is performed to form a desired line pattern (not shown). It is also possible to obtain.

Next, a fourth embodiment will be described with reference to the forming process diagram shown in FIG. The first step shown in FIG. 4A is performed. In this step, the pattern 42 is formed on the substrate 41 in the same manner as the method of forming the pattern (13) described in the first embodiment. Then, a first film 43 made of, for example, polycrystalline silicon is formed in a state of covering the pattern 42 by, for example, a normal chemical vapor deposition method. Then, a second film 44 made of a planarizing layer is formed on the surface of the first film 43 by a normal chemical vapor deposition method. Then, the second film 44 is subjected to a normal etch-back process until the second film 44 has a height equivalent to that of the pattern 42.
The portion indicated by the two-dot chain line in 4 is removed.

Then, the second step shown in FIG. 4B is performed. In this process, by the usual etch back process,
The portion of the first film 43 on the pattern 42 indicated by the chain double-dashed line is removed. Then, the upper surface of the pattern 42 is exposed.

Subsequently, the third step shown in FIG. 4C is performed. In this step, the pattern 42 (the portion indicated by the chain double-dashed line) and the second film 44 are formed by normal etching.
(The portion indicated by the one-dot chain line) is removed.

Thereafter, a fourth step shown in FIG. 4 (4) is performed. In this step, the portion of the first film 43 covered with the second film (44) is anisotropically etched so that the etching proceeds in a direction substantially perpendicular to the substrate 41.
(The part indicated by the chain double-dashed line) and the upper part of the first film 43 (1
(Dashed line) and are removed. Then, the remaining first film 43 becomes the line pattern 45.

In the method of forming a line pattern according to the fourth embodiment, the second film 44 is removed to a height substantially the same as that of the pattern 42, so that the remaining second film 44 becomes a third film.
The same function as the second sidewall (35) described in the above embodiment. Therefore, since the line pattern 45 is formed in a self-aligned manner, the width of the line pattern 45 is equal to that of the first film 4.
It is determined by the film thickness of 3. Therefore, the line pattern 45
Is formed to have a width of about 0.1 μm or less.

The line pattern 45 formed by the above method is formed in a rectangular shape on the surface of the substrate 41. Therefore, a desired line pattern (not shown) can be obtained by removing the line pattern 45 in an unnecessary portion by usual photolithography and etching. It is also possible to remove the unnecessary portion of the first film 43 after the third step and then perform the fourth step to obtain a desired line pattern (not shown).

[0030]

As described above, according to the present invention,
Since the line pattern is formed using the film formed on the sidewall of the pattern, the line pattern is formed in a self-aligned manner. Therefore, the width of the line pattern can be determined by the film thickness of the sidewall forming film formed on the side wall of the pattern or the film thickness of the first film. Therefore, a line pattern having a width of about 0.1 μm or less can be formed. Therefore, for example, a transistor having a very short gate length can be formed, and high integration of the transistor can be further advanced.

[Brief description of drawings]

FIG. 1 is a diagram illustrating a forming process according to a first embodiment.

FIG. 2 is a diagram illustrating a forming process according to a second embodiment.

FIG. 3 is a diagram illustrating a forming process according to a third embodiment.

FIG. 4 is a diagram illustrating a forming process according to a fourth embodiment.

[Explanation of symbols]

 11 Substrate 13 Pattern 14 Sidewall Forming Film 15 Sidewall 16 Line Pattern 17 Top of Line Pattern 31 Substrate 32 Pattern 33 First Film 34 Second Film 35 First Sidewall 36 Second Sidewall 37 Second Upper part of sidewall 38 Line pattern 41 Substrate 42 Pattern 43 First film 44 Second film 45 Line pattern

Claims (4)

[Claims] 1. After forming a pattern on a substrate, a side wall forming film is formed in a state of covering the pattern, and then a part of the side wall forming film other than the side wall forming film formed on the side wall of the pattern is formed. A first step of removing the sidewall formation film to form a sidewall on the sidewall of the pattern; and a second step of removing the pattern and leaving the sidewall to form a line pattern with the sidewall. And a step of forming a line pattern. 2. The method for forming a line pattern according to claim 1, wherein after the first step and the second step, a step of removing only an upper portion of the line pattern is performed. And a method of forming a line pattern. 3. After forming a pattern on a substrate, a first film is formed so as to cover the pattern, and then the first film is formed.
A second step of forming a second film on the surface of the film, and then forming a first sidewall of the second film on a side portion of the first film on the side wall side of the pattern, Using the first sidewall as an etching mask,
A portion of the first film other than the portion of the first film between the first sidewall and the pattern is removed, and a second film of the first film is formed on a sidewall of the pattern. A second step of forming sidewalls; a third step of removing the pattern and the second sidewalls, leaving only the second sidewalls; and a step of being covered with the first sidewalls. The method of forming a line pattern, comprising: performing a fourth step of forming a line pattern by removing the second side wall and the upper portion of the second side wall of the existing portion. 4. After forming a pattern on a substrate, a first film is formed so as to cover the pattern, and then the first film is formed.
Forming a second film having a flat surface on the surface of the first film, and then removing the second film until the second film has substantially the same height as the pattern; and the first step on the pattern. A second step of exposing the pattern by removing the second film, a third step of removing the pattern and the second film, and a step of covering the second film in the second step. And a fourth step of forming a line pattern with the remaining first film by removing the portion of the first film and the upper portion of the first film that were left open. Forming method.