JPH05283378A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To obtain an etching pattern where the width of wiring and the diameter of a hole are in accord with the dimension at design, in the etching process using a photoresist pattern. CONSTITUTION:When forming a photoresist pattern on a film 2 to be etched, and etching the film 2 to be etched, with the photoresist pattern 3 as a mask, a protective film 5 with a required thickness is stacked on the photoresist pattern 3 and the film 2 to be etched, and this protective film 5 and the film 2 to be etched are etched at the same time. Since the protective film 5 is left on the side of the photoresist pattern 3, the side etching of the film 2 to be etched is suppressed, and the error in etching dimension by side etching is suppressed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a semiconductor device, and more particularly to improvement of an etching process.

[0002]

2. Description of the Related Art In a conventional semiconductor device etching process, as shown in FIG. 4A, first, a photoresist pattern 23 is patterned on an aluminum film 22 of a silicon wafer 21 which is a film to be etched. Then
As shown in FIG. 4B, this photoresist pattern 23
Using the mask as a mask, the aluminum film 22 is etched by the etching gas plasma 26 of BCl ₃ and Cl ₂ to obtain the aluminum wiring 27.

[0003]

In such a conventional etching process, side etching is caused by etching, the line width of the formed aluminum wiring 27 becomes narrower than that of the photoresist pattern 23, and etching according to design dimensions is performed. There was a problem that the pattern could not be obtained. Further, in the case of forming holes by etching, there is a problem that a fine etching pattern having a resolution higher than that of the photoresist cannot be obtained by side etching and the hole diameter becomes larger than the designed size. An object of the present invention is to provide a method of manufacturing a semiconductor device, which can obtain an etching pattern having a wiring width and a hole diameter as designed.

[0004]

According to the present invention, a photoresist pattern is formed on a film to be etched, and when the film to be etched is etched using the photoresist pattern as a mask, the photoresist pattern and the film to be etched are formed. A protective film having a required film thickness is deposited on the protective film and the film to be etched is simultaneously etched.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings. FIG. 1 is a sectional view showing a first embodiment of the present invention in the order of manufacturing steps. First, as shown in FIG. 1A, a photoresist pattern 3 is patterned on an aluminum film 2 of a silicon wafer 1. Then, as shown in FIG. 1 (b), C
A CF ₂ polymer protective film 5 is deposited on the photoresist pattern 3 and the aluminum film 2 by a gas plasma 4 of HF ₃ .

Thereafter, as shown in FIG. 1 (c), BCl ₃ ,
The protective film 5 and the aluminum film 2 are etched with an etching gas plasma 6 of Cl ₂ to form an aluminum wiring 7. By this etching, since the protective film 5 is left on the side surface of the photoresist pattern 3, the etching of the aluminum film 2 is suppressed by the thickness thereof. Therefore, even if side etching occurs in the aluminum film 2, the width dimension of the aluminum wiring 7 does not become smaller than the width of the photoresist pattern 3.

FIG. 2 is a sectional view showing the second embodiment of the present invention in the order of manufacturing steps, and here shows an example in which a hole is opened. First, as shown in FIG. 2A, the silicon wafer 1
A photoresist pattern 13 is formed on the first SiO ₂ film 12. Then, as shown in FIG. 2B, C
Photoresist pattern 1 with HF ₃ gas plasma 14
3 and a protective film 15 of CF ₂ polymer is deposited on the SiO ₂ film 12.

Then, as shown in FIG. 2C, CF ₄ , C
Protective film 1 with etching gas plasma 16 of HF ₃ and Ar
5 and the SiO ₂ film 12 are etched. By this etching, the protective film 15 becomes the photoresist pattern 13.
Since it is left on the side surfaces of the SiO ₂ film 12,
Of the photoresist pattern 13 is suppressed.
Holes 17 with smaller diameter dimensions are obtained.

By properly setting the thickness of the protective film, the side etching amount of the film to be etched can be appropriately adjusted depending on the thickness of the protective film left after etching. For example, as shown in FIG. 3, in the conventional technique, the protective film thickness is 0Å, so the side etching amount is 0.2 μm.
However, when the protective film thickness is 3000 Å, the side etching amount becomes 0 μm, and the etching pattern according to the design dimension can be obtained.

[0010]

As described above, according to the present invention, etching is performed after depositing a protective film on a photoresist pattern, so that the protective film suppresses side etching of the film to be etched. Therefore, by appropriately adjusting the thickness of the protective film, it is possible to obtain an etching pattern having a line width or a hole diameter as designed.

[Brief description of drawings]

FIG. 1 is a sectional view showing a first embodiment of the present invention in the order of manufacturing steps.

FIG. 2 is a sectional view showing a second embodiment of the present invention in the order of manufacturing steps.

FIG. 3 is a diagram showing a relationship between a film thickness of a protective film and a side etching amount.

FIG. 4 is a cross-sectional view showing a conventional manufacturing method in the order of steps.

[Explanation of symbols]

 1 Silicon wafer 2 Aluminum film 3 Photoresist pattern 5 Protective film 7 Aluminum wiring

Claims (1)

[Claims] 1. A method of manufacturing a semiconductor device, comprising: forming a photoresist pattern on a film to be etched; and etching the film to be etched using the photoresist pattern as a mask. A method of manufacturing a semiconductor device, comprising: depositing a protective film having a required film thickness on top of the film; and simultaneously etching the protective film and the film to be etched.