JPS62143052A - Mask - Google Patents

Abstract

PURPOSE:To correct the exposure width changing widely and narrowly due to the height of a resist film by reducing or expanding the pattern width of a mask corresponding to the height of the resist film stuck at the surface of a semiconductor wafer. CONSTITUTION:In accordance with the height of the surface of an applied resist film 4, a reducing part 2a is formed to the mask pattern corresponding to a high part 4a, an expanding part 2b is formed to the mask pattern corresponding to a low part 4b, and the correction is executed. Thus, the resist pattern formed actually can be formed as the pattern of the desired constant width. Consequently, when the resist pattern is used and wiring, etc., are formed, the occurrence of the shorting at the division of the disconnection, adjoining wiring, etc., can be prevented and the semiconductor device with a high reliability can be manufactured.

Description

[Detailed Description of the Invention] (Technical Field) The present invention relates to a technique that is effective when applied to masks used in the manufacture of semiconductor devices. Note that the mask referred to herein also includes a so-called reticle used for reduction exposure. It is something that can be done.

[Background technology]

In the so-called wafer process of the manufacturing process of semiconductor devices, masks are used to form circuit elements on a semiconductor substrate such as silicon (Si) and to form wiring for establishing conduction of the circuit elements. Ru.

The above-mentioned mask is generally formed by covering a transparent substrate such as quartz glass with a light-shielding film made of chromium (Cr) or the like in a predetermined pattern.

Incidentally, semi-quadram wafers are often formed with multiple layers of electrodes, wiring, etc., and the surface of such a semiconductor wafer is generally not uniform in height.

When further forming wiring, etc. on the surface of a semiconductor wafer that has heights and depressions on its surface as described above, it is necessary to deposit a resist film on the surface and transfer a mask pattern to the resist film. be exposed.

However, if there are elevations and depressions on the surface of the semiconductor wafer, there will inevitably be elevations and depressions in the resist film. Therefore, the distance from the mask pattern to the surface of the resist film varies depending on the location. Therefore, when using a normal mask with a linear mask pattern formed on the assumption that the surface of the resist film is flat, even if the width of the pattern is constant, the resist film will be damaged due to light diffraction phenomenon. The pattern 11 that is exposed to light will vary in width depending on the location. As a result, the inventors have discovered that the wiring may be disconnected or short-circuited, which poses a problem in reliability.

Regarding masks, please refer to Kogyo Kenkyukai Co., Ltd., 1982.
It is explained on pages 103 and below of the November 1981 issue of "Electronic Materials", published on November 15, 2015.

[Purpose of the invention]

An object of the present invention is to provide a technique that allows an accurate pattern to be transferred to a resist film attached to a semiconductor wafer surface even if the surface of the semiconductor wafer has heights and depressions.

The above and other objects and novel features of the present invention will become apparent from the description of this specification and the accompanying drawings.

[Summary of the invention]

A brief overview of typical inventions disclosed in this application is as follows.

That is, by shrinking or expanding a mask pattern formed on a mask in accordance with the height of a resist film deposited on the surface of a semiconductor wafer, the resist film is exposed using the mask, and then developed to remove the resist. When forming a pattern, the actual resist pattern can be accurately formed with a predetermined width by being able to correct the wide and narrow changes during exposure due to the height of the resist film.

〔Example〕

FIG. 1 is a partial plan view showing an enlarged part of a mask pattern formed on a mask according to an embodiment of the present invention, and FIG. 2 is a schematic diagram of the surface state of a semiconductor wafer to which the mask pattern is exposed. It is an enlarged partial sectional view showing. Moreover, FIG. 3 is a schematic cross-sectional view showing the mask of this example.

The mask of this embodiment has a mask pattern 2 made of a light-shielding film made of chromium (Cr) or the like having a predetermined shape on a transparent substrate 1 made of glass or the like.
is formed by adhesion. This mask is used to form a resist pattern by exposing the resist film 4 deposited on the surface of the semiconductor wafer 3 as shown in FIG. 2 and transferring the mask pattern. The formed resist pattern is used, for example, to form a wiring made of aluminum or the like having a certain width.

Therefore, if the resist pattern is not formed with an accurate constant width, the wiring itself cannot be formed with a constant width.

Incidentally, the resist film 4 is exposed to light by placing a mask at a predetermined position above the semiconductor wafer 3 and by irradiating light from above the mask. Therefore, if the surface of the resist film 4 is flat, the distance between the mask pattern and the mask pattern is constant, so simply forming a pattern with a constant width will cause the transferred resist pattern to also have a constant width. can be formed.

However, as shown in FIG. 2, many electrodes and interconnections 5 are made of silicon dioxide (SiO□) near the surface of the semiconductor wafer 3.
It is formed by stacking many layers electrically isolated by an insulating film made of the like.

Therefore, the surface of the insulating film 6 located at the top layer is not flat, and has a high part and a low part as shown in FIG. Therefore, the resist film 4 deposited on the insulating film 6
Also, a high portion 4a and a low portion 4b are inevitably present.

When there are heights and depressions on the surface of the resist film 4 as described above, the distance between the mask pattern and the surface of the resist film differs depending on the location. Therefore, when exposing a mask pattern of a certain width,
The resist pattern is formed to be wide in the high portion 4a and narrow in the low portion 4b. This is understood to be due to the fact that the longer the distance, the larger the exposed area becomes due to the phenomenon of light diffraction.

Therefore, as in the mask of this embodiment, depending on the height of the surface of the applied resist film 4, the mask pattern corresponding to the high part 4a has a reduced part 2a, and the mask pattern corresponding to the low part 4b has an extended part. 2b and perform its correction. By doing so, the resist pattern that is actually formed can be formed as a pattern with a desired constant width.

As explained above, by using the mask of this embodiment, the unevenness of the surface of the semiconductor wafer 3 inevitably affects the surface of the resist film 4 deposited on the surface, and the surface has high and low points. Even if such a pattern occurs, it is possible to always form a pattern with the desired exact dimensions.

Therefore, when wiring or the like is formed using the resist pattern, it is possible to prevent disconnections or short circuits between adjacent wirings, etc., and it is possible to manufacture a highly reliable semiconductor device.

In addition, in forming the mask in this embodiment, information on the height of the surface of the entire semiconductor wafer 3 is obtained by actually measuring or theoretically calculating the height of the surface of the semiconductor wafer 3, and based on the information. This can be achieved by designing a pattern based on this.

〔effect〕

(1) By reducing or expanding the pattern width of the mask in accordance with the height of the resist film deposited on the surface of the semiconductor wafer, the resist film is exposed using the mask, and then developed to resist the resist film. When forming a pattern, the resist pattern can be accurately formed with a predetermined width by being able to correct the wide and narrow changes during exposure due to the height of the resist film.

(2) According to (11) above, electrodes, wiring, etc. can be accurately formed on the semiconductor wafer, and therefore electrical defects caused by short circuits, disconnections, etc. can be prevented.

(3) According to (2) above, it is possible to improve the reliability of the semiconductor.

Although the invention made by the present inventor has been specifically explained above based on Examples, it goes without saying that the present invention is not limited to the Examples and can be modified in various ways without departing from the gist thereof. Nor.

For example, in the embodiment, the application is shown to be applied to a semiconductor wafer with clear high and low parts, but the mask pattern is not limited to this, and the width continuously changes in consideration of the slightly changing height. Needless to say, it may also form a .

[Brief explanation of drawings]

FIG. 1 is a partial plan view showing an enlarged part of a mask pattern formed on a mask according to an embodiment of the present invention, and FIG. 2 is a schematic diagram showing the surface state of a semiconductor wafer to which the mask pattern is exposed. The enlarged partial sectional view, FIG. 3, is a schematic sectional view showing the mask of this embodiment. 1... Transparent substrate, 2... Mask pattern, 2a...
- Reduction part, 2b... Expansion part, 3... Semiconductor wafer,
4... Resist film, 4a... High part, 4b... Low part, 5... Wiring, 6... Insulating film. Cut' Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] 1. A mask whose pattern width is reduced or expanded in accordance with the height of a resist film deposited on a semiconductor wafer.