JPH0330332A - Pattern forming method - Google Patents

Abstract

PURPOSE:To suppress side etching effectively and to obtain a pattern having the approximately designed width by providing dummy masks at large spaces between the patterns when a pattern mask is provided. CONSTITUTION:When a pattern mask 3a is provided, dummy masks 3b and 3c are provided at the large spaces between patterns. Namely, the pattern 3a covers a part corresponding to a specified pattern. The dummy masks 3b and 3c cover parts where the large spaces remain between the patterns. When the Al thin film at an unmasked part is removed by reacting ion etching, an Al pattern 2a and dummy patterns 2b and 2c are formed. Side etching is hard to progress at the Al pattern 2a since there are the dummy masks 3b and 3c. The pattern width that is the approximately the mask width is obtained. Thus, the pattern having the approximately designed width can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a pattern forming method, and particularly to a pattern forming method made of a metal thin film.

[Conventional technology]

As a pattern made of a metal thin film, there is an Af pattern in a semiconductor device, for example, an AN pattern 22 for wiring formed on the surface of an insulating base material 21, as shown in FIG.

In this case, the insulating base material 21 is exemplified by a substrate in which an insulating layer is formed on a semiconductor layer.

One of the conventional methods for forming this AI (aluminum) pattern 22 is the following method.

First, AN thin IIl was applied to the entire surface of the insulating base material 21! (metal thin film). Next, a portion of this Al thin film corresponding to a predetermined pattern is covered with a pattern mask, and then the unmasked portion of the Al thin film is subjected to RIE (reactive ion etching + ReacLi), which is one of the dry etching methods.
selectively removed by a ve ton etching method. In this way, the Al pattern 22 is completed. When this RIE method is used, there is an advantage that the pattern width can be made narrower than when a wet etching method is used.

[Problem to be solved by the invention]

However, if there is a large empty space between patterns, there is a problem that the line width of the pattern in the vicinity becomes much smaller than the needle setting value, resulting in low reliability. As shown in FIG. 5, in the case of the pattern 22 near a large empty space, etching progresses to the bottom of the pattern mask 23 (side etching), resulting in a thin pattern.

In view of the above circumstances, it is an object of the present invention to provide a pattern forming method that can effectively suppress side etching when forming a pattern made of a metal thin film using dry etching.

[Means to solve the problem]

In order to solve the above problem, in the pattern forming method of the present invention, when applying a pattern mask, a dummy mask is applied in areas where there is a large empty space between patterns.

Metal in this invention? As an lJ film, AI! Examples include, but are not limited to, a thin film, a copper thin film, a gold thin film, a platinum thin film, etc.

Further, as the mask, for example, one formed using a photosensitive resist material or the like may be used, but the mask is not limited thereto.

Examples of the dry etching method include RIE (Reactive ion etching).
Examples include, but are not limited to, the ``Ching'' method and the like.

[For production]

In the pattern forming method according to the present invention, even if there is a large empty space between patterns, side etching is difficult to proceed because a dummy pattern is provided there.
A pattern with a width approximately as designed can be obtained.

Furthermore, since the dummy mask is formed at the same time as the pattern mask, there is virtually no change in labor or cost, and implementation is extremely easy.

〔Example〕

Hereinafter, one embodiment of the pattern forming method according to the present invention will be described in detail with reference to the drawings.

First, as shown in FIGS. 1(a) and (b), an insulating base material 1
AIt thin 1 on the entire surface! ! ! (Metal thin film) 2 is formed, and then a mask 3 is formed using a photosensitive resist material or the like. The mask 3 consists of a pattern mask 3a and dummy masks 3b and 3c, and these masks 3a% 3 bs
As mentioned above, all of 3c are formed at the same time. The pattern mask 3a is Al1111m! 2
dummy mask 3.
b and 3c are formed to cover large empty spaces between patterns.

After forming the mask 3, the unmasked portions of the AJ thin film are subjected to RIE (reactive ion etching), which is a dry etching method.
ng) method.

Then, as shown in FIG. 2, an AI pattern 2a and dummy Al patterns 2b and 2c are formed. A1
Since the pattern 2a includes the dummy masks 3b and 3c, side etching is difficult to proceed as shown in FIG. 3, and the pattern width is approximately equal to the width of the mask.

Note that the shape of the dummy mask is not limited to that of the embodiment, and any shape that allows light to pass through may be used as appropriate, and the dummy Al pattern may be removed thereafter as necessary.

〔Effect of the invention〕

As described above, in the pattern forming method according to the present invention, when applying a pattern mask, a dummy mask is also applied in areas with large empty spaces between patterns, so dry etching is used to form a metal thin film. Even when forming a pattern, side etching can be effectively suppressed, and a pattern having a width substantially as designed can be obtained.

[Brief explanation of drawings]

FIGS. 1(a) and 1(b) are drawings showing a base material with a pattern mask and a dummy mask in an example of the pattern forming method of the present invention, and FIG. 1(a) is a plan view, and FIG. b) is a partial cross-sectional view. FIG. 2 is a plan view showing the pattern obtained by this example, and FIG.
FIG. 4 is a partial cross-sectional view for explaining the state immediately after dry etching in the above-mentioned example, and FIG.
FIG. 5 is a partial sectional view for explaining the state immediately after dry etching in this conventional method. 1...Insulating base material (base material) 2...Total bending thin film (, l
thin film) 2a...AN pattern 2b, 2C...
Dummy Aβ pattern 3a...pattern mask
3b, 3c...dummy mask

Claims (1)

[Claims] 1. A pattern forming method in which a portion of a metal thin film formed on the surface of a base material corresponding to a predetermined pattern is covered with a pattern mask, and unmasked portions of the metal thin film are selectively removed by dry etching. A pattern forming method characterized in that when applying a dummy mask, a dummy mask is applied to areas with large empty spaces between patterns.