JPS6217870B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a semiconductor device that prevents disconnection of wiring.

A conventional device of this type has a two-layer polycrystalline silicon film structure formed on a relatively thick silicon oxide film, as shown in FIG. FIG. 1a is a plan view, and FIG. 1b is a sectional view taken along the dotted line AA' in FIG. 1a.

In both FIGS. 1a and 1b, 1 is a relatively thick silicon oxide film formed on a silicon substrate, and 2 is a polycrystalline silicon film formed on a relatively thick silicon oxide film 1. (hereinafter referred to as a first polycrystalline silicon film), 3 is a relatively thin silicon oxide film that insulates between the two layers of polycrystalline silicon films, and 4 is a relatively thick silicon oxide film 1 and a relatively thin silicon oxide film 3. This is a polycrystalline silicon film (hereinafter referred to as a second polycrystalline silicon film) formed in the second polycrystalline silicon film.

However, in FIG. 1b, after forming the first polycrystalline silicon film 2, the relatively thick silicon oxide film 1 is partially etched away using the first polycrystalline silicon film 2 as a mask, and then the relatively thick silicon oxide film 1 is removed by corrosion. An example will be shown in which a silicon oxide film 3 and a second polycrystalline silicon film 4 are formed.

In the two-layer polycrystalline silicon film structure formed in this way, a cavity 5 is formed in the silicon oxide film 3 along the edge of the first polycrystalline silicon film 2 before forming the second polycrystalline silicon film 4. ing.

Therefore, when forming the second polycrystalline silicon film 4, this second polycrystalline silicon film 4 is
If the first polycrystalline silicon film 2 is bent at an acute angle from the edge as shown in FIG. As a result, the portion of the second polycrystalline silicon film 4 corresponding to the acute angle portion 6 is largely side-etched, and a cavity 7 is generated as shown in FIG. 1b. Then, there is a problem that the second polycrystalline silicon film 4 is disconnected.

This invention was made in order to solve the problems of the conventional ones as described above, and the second polycrystalline silicon film 4 is separated from the edge of the first polycrystalline silicon film 2 by an acute angle. It is an object of the present invention to provide a semiconductor device that can prevent disconnection of the second polycrystalline silicon film 4 by causing bending.

Embodiments of the semiconductor device of the present invention will be described below with reference to the drawings. FIG. 2 is a plan view showing the configuration of one embodiment, and in this FIG.
The polycrystalline silicon film 4 is a second polycrystalline silicon film.

As shown in FIG. 2, the first polycrystalline silicon film 2
A second polycrystalline silicon film 4 formed on the top with a silicon oxide film 3 interposed therebetween in a substantially orthogonal state is perpendicular to the edge of the first polycrystalline silicon film 2 by an allowance l (l: more than μ) for mask alignment. The second polycrystalline silicon film 4 is bent at an acute angle from the first polycrystalline silicon film 2 using this margin l.

With this shape, the portion of the second polycrystalline silicon film 4 corresponding to the edge of the first polycrystalline silicon film 2 will not have an acute angle portion 6 as shown in FIG.
Accordingly, stagnation of liquid or gas during etching is eliminated, and breakage of the second polycrystalline silicon film 4 at the edge of the first polycrystalline silicon film 2 can be prevented.

Therefore, as shown in FIG. 1b, if there is a cavity 5 that penetrates inside the edge of the first polycrystalline silicon film 2 before forming the second polycrystalline silicon film 4, or if the second polycrystalline silicon film 4 is This is particularly effective when the corrosion removal of the silicon film 4 requires a long manufacturing time.

In the above embodiment, the case of a two-layer polycrystalline silicon film structure was explained, but the same applies to the case of wiring made of aluminum or the like.

Furthermore, the same applies to the case where a step is formed, which does not require a two-layer wiring, but in which a cavity 5 extending inside as shown in FIG. 1B is formed.

As described above, according to the semiconductor device of the present invention, after extending the second polycrystalline silicon film from the edge of the second polycrystalline silicon film by a predetermined margin of mask misalignment, the second polycrystalline silicon film is Since the film is bent at an acute angle with respect to the first polycrystalline silicon film, there is an effect that disconnection of wiring can be prevented without increasing the number of masks.

[Brief explanation of the drawing]

FIG. 1a is a plan view showing a conventional semiconductor device, FIG. 1b is a sectional view taken along the dotted line A-A' in FIG. FIG. 2 is a plan view of one embodiment. 1... Relatively thick silicon oxide film, 2... Polycrystalline silicon film, 3... Relatively thin silicon oxide film, 4...
Polycrystalline silicon film, 5... Cavity penetrated inside,
6...Acute angle part. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Scope of Claims] 1. In a semiconductor device having two layers of polycrystalline silicon films, upper and lower, the upper polycrystalline silicon film formed to cross the lower polycrystalline silicon film is Extend at right angles from the edge of the membrane by a certain amount of mask misalignment,
A semiconductor device characterized in that the upper polycrystalline silicon film is bent at an acute angle from the extended end with respect to the lower polycrystalline silicon film. 2. The semiconductor device according to claim 1, wherein the margin for the predetermined mask misalignment is 1 μ or more.