JPS63151027A - Pattern formation - Google Patents

Abstract

PURPOSE:To make it possible to form tapered parts without changing dry etching conditions, by combining resists having different contrasts, forming patterns, forming the tapered parts for the upper resist pattern, and transferring the pattern by the dry etching. CONSTITUTION:First resist 3 having good contrast is formed on a first film 1, which is a film to be etched and formed on a substrate 2. Thereafter, second resist 4 having poor contrast is formed. Then, a first resist pattern 3' and a second resist pattern 4' are formed. At this time, the second pattern 4' is formed so as to have tapered parts. When etching is performed by an anisotropic etching method, the first film 1 is vertically etched. A first film pattern 1' having tapered parts on its upper part can be formed by transfer when further etching is performed. Thereafter, the first resist pattern 3' is removed, and then a second film 5 is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a pattern forming method, and more particularly to a resist pattern forming method for taper etching by dry etching.

2. Description of the Related Art With the miniaturization of semiconductor devices, anisotropic dry etching technology has been used to form patterns.

An example of dry etching using a conventional resist pattern forming method is shown in FIGS.

The first film 1 (s i , 310
A radiation-sensitive resin film 11 (hereinafter referred to as resist) is formed on the main surface of the substrate 2 on which 2°PoLySi, A1, etc.) is formed (FIG. 2A) by a spin coating method or the like.

Next, a resist pattern 11' is formed using a predetermined method (FIG. 2B).

Next, using this resist pattern 11' as a mask, the first film 1 is etched using an anisotropic dry etching method to form a first film pattern 1' (FIG. 2C).
.

Thereafter, after removing the resist pattern 3', a second film 6 is formed (FIG. 2D).

Problems to be Solved by the Invention When the pattern is formed by the method described above, the first film pattern 1' is formed in a very vertical shape.

When the second film 5 is formed in this state, the first film pattern 1
It becomes difficult to form the second film 5 in the groove formed by '. This phenomenon varies depending on the relationship between the width and depth of the groove, but nowadays, as patterns become finer, the decrease in width is greater than the decrease in depth. It is difficult to uniformly form the film 4 in the groove.

Therefore, in recent years, a method has been commonly used in which the dry etching conditions are changed midway through and the upper part of the pattern is tapered to improve the coverage of the second film. In addition to problems such as poor reproducibility and decreased selectivity with respect to the underlying layer, etching conditions had to be selected individually depending on the type of film to be etched, resulting in very poor workability.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a method for forming a resist pattern that can form a taper in the upper part of the pattern without changing the dry etching conditions.

Means for Solving the Problems In order to solve the above problems, the present invention forms a resist pattern by combining resists with different contrast properties, and forms a taper in the upper resist pattern. A pattern having a tapered upper part is formed by transferring the shape of the resist pattern onto the film to be etched by dry etching.

Function: By the method of the present invention, a tapered pattern can be formed regardless of dry etching conditions.

Embodiment FIGS. 1A to 1E show an embodiment in which pattern formation is performed by the method of the present invention.

First, a first resist 3 with good contrast (high γ value indicating the contrast of the resist) is formed on the main surface of the substrate 2 on which the first film 1, which is the film to be etched, is formed, using a spin coating method or the like. After that, a second resist 4 having poor contrast (low γ value) is formed (FIG. 1A).

Next, a first resist pattern 3' and a second resist pattern 4' are formed by a predetermined method.

At this time, the second resist pattern 4' with poor contrast
is formed with a taper (Fig. 1B).

Next, when etching is performed using an anisotropic dry etching method using the first resist pattern 3' and the second resist pattern 4' as masks, the taper of the second resist pattern 4' is transferred to the first resist pattern. Since the etching shape of the first film 1 is determined by the shape of the first resist pattern 3', the first film 1 is etched vertically (FIG. 1C).

When etching is further performed, the shape of the first resist pattern 3' to which the taper of the second resist pattern 4' has been transferred is transferred, and a first film pattern 1' having a taper at the top can be formed. (Figure 1D)
.

Thereafter, after removing the resist pattern 3' of the tube 1, a second film 5 is formed (FIG. 1E).

By forming a pattern using the above method, a taper can be formed at any angle by arbitrarily selecting the γ value of the resist, regardless of the dry etching conditions and regardless of the type of film to be etched. I can do it.

The depth of the taper can also be arbitrarily selected by controlling the thickness of the resist through the selection ratio between the film to be etched and the resist.

Effects of the Invention As described above, by using the method of the present invention, a pattern having a taper at the top can be formed regardless of the dry etching conditions or the type of film to be etched, and its industrial value is big.

[Brief explanation of the drawing]

1A to 1E are process cross-sectional views of an embodiment of pattern formation using the method of the present invention, and FIGS. 2A to 2D are process cross-sectional views of an embodiment of pattern formation using the conventional method. DESCRIPTION OF SYMBOLS 1...First film, 2...Substrate, 3'...
...First resist pattern, 4'...
- Second resist pattern, 6... Second film. Name of agent: Patent attorney Toshio Nakao and 1 other person 1st
Figure 1 - 2 ~ - 1 wholesale 3 - 1 tea 4 - 1 fu 2/1'' Figure 1 5---''g, pnyl pod Figure 2

Claims (1)

[Claims] (1) A step of forming a first radiation-sensitive resin pattern with good contrast on the main surface of the substrate, a step of forming a second radiation-sensitive resin pattern having an arbitrary taper, and a step of forming the first radiation-sensitive resin pattern on the main surface of the substrate. A pattern forming method comprising the steps of performing anisotropic dry etching using a radiation sensitive resin pattern and a second radiation sensitive resin pattern as a mask.