JPS60113473A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To form the end of a mask pattern to a required width by compensating the end for its taper at the time of etching by a method wherein this pattern is made wider than the required width in the neighborhood of the end part. CONSTITUTION:A field oxide film 2 is so formed as to surround the element- forming region of an Si substrate, and the source and drain are formed in the surface part of the substrate surrounded thereby at a required distance from each other. A gate oxide film 5 is formed on the substrate, and a polycrystalline layer 6 is formed thereon. At the end of a photo resist mask 7 where a gate electrode is to be formed, the width is kept large by etching the layer 6; accordingly, the end part of the gate electrode is compensated for its taper due to over-etching.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an improvement in a method for manufacturing a semiconductor device by etching through a mask pattern.

The following will explain the case of manufacturing a MOS transistor (MO8T) as an example.

[Prior art]

FIG. 1 is a sectional view showing the steps of forming a gate in manufacturing a conventional MO8T, and FIG. 2 is a plan view thereof. A field oxide film (2) is formed so as to surround the element formation region of the silicon substrate (1), and sources (3) are formed on the surface of the silicon substrate (1) surrounded by this film at a required distance from each other.
A gate oxide film (5) was formed on the silicon substrate (1) including the drain (4), and a polysilicon layer (6) to become a gate electrode was further formed on the gate oxide film (5). Later, this polysilicon layer (6) is etched to form a photoresist mask (7) for forming a gate electrode.

As is well known, the method for forming the photoresist mask (7) is to deposit a photoresist film on the entire surface of the polysilicon layer (6), and then expose it to light using a mask of a desired pattern.
After development, a photoresist mask with the same pattern as the above mask (power can be obtained).

The MO8T is completed by etching the polysilicon layer (6) through this photoresist mask (7) to form a gate electrode (6a) as shown in the plan view of FIG. Of course, the source (3) and drain (4) are formed by forming the gate electrode (6a), removing the gate oxide film (5) other than directly below it, and then diffusing impurities thereon. There is also.

Now, in this conventional method, a photoresist mask (
When etching the polysilicon layer (6) through the polysilicon layer (6), the edge of the gate electrode (6a) becomes thinner than the mask pattern as shown in FIG. The gate length in this area is shortened.

FIG. 4 is a plan view showing a conventional method to avoid this problem, in which the photoresist mask in which the gate electrode is to be formed is extended far beyond the channel region of the MO8T, and at its end a polysilicon layer (6) is formed. This method is designed to prevent overetching from affecting the channel region even if overetching occurs in the MO8T as shown in the figure.
There is a problem that the area on the wafer for forming the wafer becomes large.

[Summary of the invention]

This invention has been made in view of the above points, and provides a method for manufacturing a semiconductor device that can form a pattern of a desired width in a desired portion without increasing the area of the wafer whose edges become thin due to overetching. It is something.

[Embodiments of the invention]

FIG. 5 is a plan view showing the stage of forming an etching mask according to an embodiment of the present invention, in which the same reference numerals as in the conventional example indicate the same parts. In this embodiment, the polysilicon layer (6) is etched to form the gate electrode. A photoresist mask (
7) Prevent the gate length of the formed gate electrode from becoming short by widening the width at the end as shown in the figure and compensating for the thinning caused by teno-over etching at the end of the gate electrode. I can do it.

In the above embodiment, the case of forming a MO8T gate electrode has been described, but the present invention can also be applied to forming wiring in other semiconductor devices.

〔Effect of the invention〕

As explained above, in the present invention, in the method of manufacturing a semiconductor device in which a portion is formed by etching through a mask having a desired pattern, the width at the end of the pattern is made wider, so that the portion is made larger than necessary. It is possible to compensate for the thinning of the end portion during etching and form the portion to the required width without increasing the length.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing the steps of forming a gate in the conventional MO8T manufacturing process, FIG. 2 is a plan view thereof, FIG. This figure is a plan view showing the step of forming an etching mask in a conventional improved method, and FIG. 5 is a plan view showing the step of forming an etching mask in an embodiment of the present invention. In the figure, (6) is a polysilicon layer, (6a) is a gate electrode, and (7) is a photoresist mask. Note that the same reference numerals in the drawings indicate the same or equivalent parts.0 Agent: Masuo Oiwa N'>4 Showa year: To the Commissioner of the Japan Patent Office1, Indication of case: Japanese Patent Application No. 58-2211082, Title of invention: Semiconductor Device manufacturing method 3, relationship with the case of the person making the amendment Patent applicant address 2-2-3 Marunouchi, Chiyoda-ku, Tokyo Name
(601) Mitsubishi Electric Co., Ltd. Representative Hitoshi Katayama Hachibu 4, Agent Address 2-2-3 Marunouchi 2-chome, Chiyoda-ku, Tokyo Target Kakuen 6, Contents of Amendment (1) Figures 1 and 1 of the drawings Figures 2, 4, and 5 are corrected as shown in the attached figures. 7. One or more drawings showing Figure 1, Figure 2, Figure 5, and Figure 5 after the catalog of attached documents has been corrected.

Claims (3)

[Claims] (1) In a method for manufacturing a semiconductor device, which includes a step of etching through a mask having a desired pattern to form a constituent portion thereof having a desired width, the pattern of the mask is made wider than the required width near the end thereof. A method for manufacturing a semiconductor device, characterized in that: (2) The method of manufacturing a semiconductor device according to claim 1, wherein the semiconductor device is an MO8 type semiconductor device, and the component formed by etching is a gate electrode. (3) The method for manufacturing a semiconductor device according to claim 1 or 2, wherein the mask is a photoresist mask.