JPS6362353A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To prevent wire breakdown when a contact electrode is formed on an electrode hole, by forming the electrode hole in two steps, in which a hole is provided in a second silicon oxide film with the first pattern of a photoresist film and a hole is provided in a phosphorus glass film and in a first silicon oxide film with the second pattern of the photoresist film. CONSTITUTION: On a semiconductor substrate 21, a first silicon oxide film 22, a phosphorus glass film 23 and a second silicon oxide film 24 are formed. A first etching hole 26 is formed in the second silicon oxdie film 24 by a photoetching method using the first pattern of a photoresist film 25. Thereafter, a second etching bole 27 is formed in the phosphorus glass film 23 and the first silicon oxide film 22 by a photoetching method using the second pattern of a photoresist film 25'. Then the cross sectional area of an electrode hole becomes gradually large toward the outlet from the bottom part. A metal film 28 is formed on the electrode hole and the three films. The three films in the vicinity of the outlet of the electrode hole have obtuse angle. Therefore, wire breakdown does not occur.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for manufacturing a semiconductor device in which the semiconductor device is provided with a triple layer consisting of a silicon oxide film, a phosphorous glass film, and a silicon oxide film.

BACKGROUND OF THE INVENTION With the development of thin film deposition technology using chemical reactions, triple-layered films for semiconductor devices have come into use. However, when forming holes for forming electrodes in the triple layer film by etching, due to the large difference in etching speed between the phosphorous glass film and the silicon oxide film, the cross section of the electrode holes formed by etching was as shown in Figure 3. The top layer of silicon oxide film protrudes like an eave. If this shape is adopted, the electrode wiring formed by the vapor deposition method will be disconnected. In FIG. 3, 1 is a semiconductor substrate, 2 is a first silicon oxide film, 3 is a phosphorous glass film, 4 is a second silicon oxide film,
5 is an electrode hole, and 6 is a metal film for electrode (wiring).

Problems to be Solved by the Invention An object of the present invention is to provide an improved method for manufacturing a semiconductor device that does not cause the above-mentioned disconnection.

Means for Solving the Problems The present invention provides a first silicon oxide film on the surface of a semiconductor substrate,
a step of sequentially forming a phosphorous glass film and a second silicon oxide film, forming a first pattern of a photoresist film on the second silicon oxide film, and forming the second silicon oxide film according to the same pattern; selectively removing the phosphorous glass film to expose the phosphorus glass film, forming a second pattern of a photoresist film on the exposed phosphorus glass film, and following the same pattern, removing the phosphorus glass film and the first silicon oxide film; selectively removing a film to expose the surface of the semiconductor substrate to form an electrode hole; A method for manufacturing a semiconductor device, comprising a step of forming a metal film on a surface of a semiconductor substrate.

According to the present invention, the electrode hole is first opened in the second silicon oxide film by the first pattern of the photoresist film, and then the electrode hole is opened in the phosphorous glass film and the first silicon oxide film by the second pattern of the photoresist film. Since it is formed in two steps during the process of opening into the membrane, the side slope of the electrode hole is relaxed, and there is no disconnection when a contact electrode is formed on this electrode hole.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described in detail with reference to embodiments shown in the accompanying drawings.

FIG. 1 is a sectional view of a semiconductor device having a Pn junction formed according to the present invention, and FIGS. 2a and 2b are process sectional views illustrating the manufacturing process thereof. In carrying out the present invention, first, as shown in FIG. 2a, a first silicon oxide film 22. Phosphorous glass film 23. A second silicon oxide film 24 is prepared. These films are formed by conventionally known methods such as thermal oxidation, sputtering, chemical vapor deposition (CVD), and vapor deposition. A first etching opening 26 is formed in this second silicon oxide film 24 by a well-known photoetching method using a first pattern of a photoresist film 25. Thereafter, as shown in FIG. 2, the phosphor glass film 23. A second etching opening 27 is formed in the first silicon oxide film 22 by a well-known photoetching method using a second pattern of a photoresist film 25'. As a result, the electrode hole consisting of the first etching opening 26 and the second etching opening 27 has a so-called pincer shape in which the cross-sectional area gradually increases from the bottom toward the exit. After that,
The semiconductor device shown in the first figure is formed by forming an electrode metal film 28 in the electrode holes and selected locations on the three Mgl by, for example, vapor deposition. Metal film 28
Because the triple membrane near the exit of the electrode hole has an obtuse angle,
There is no risk of wire breakage.

According to this embodiment, the number of steps is increased, which may seem disadvantageous, but the increase in the number of steps does not pose a problem as a whole, since disconnections in wiring can be significantly reduced.

Effects of the Invention According to the present invention, when forming an electrode hole in an insulating film having a triple-layer structure, first, a first pattern of a photoresist film is applied to the second silicon oxide film as the uppermost layer. , a first etching opening with a large diameter is formed, and then a second pattern of a photoresist film is formed on the phosphorous glass film as the next layer and the first silicon oxide film as the bottom layer. Then, a second etched opening with a smaller diameter is formed.
The electrode hole is in the shape of a dovetail with a gently sloped side surface. Therefore, when a contact electrode is formed in the electrode hole, there is no disconnection at the upper surface of the opening, thereby improving the manufacturability and quality of the semiconductor device.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a semiconductor device formed by implementing the present invention, FIGS. 2a and 2b are sectional views in order of the manufacturing process thereof,
FIG. 3 is a sectional view of a conventional semiconductor device. 21... Semiconductor substrate, 22... First silicon oxide film, 23... Phosphorus glass film, 24...
...Second silicon oxide film, 25.25'...
...Photoresist film, 26...First opening,
27...Second opening, 28...Metal film for electrode. Name of agent: Patent attorney Toshio Nakao and one other person Figure 1

Claims (1)

[Claims] a step of sequentially forming a first silicon oxide film, a phosphorous glass film, and a second silicon oxide film on the surface of the semiconductor substrate; forming a first pattern of a photoresist film on the second silicon oxide film; selectively removing the second silicon oxide film to expose the phosphorous glass film according to the pattern; forming a second photoresist film on the second silicon oxide film and the exposed phosphorous glass film; forming a pattern, and selectively removing the phosphorous glass film and the first silicon oxide film to expose the semiconductor substrate surface and forming an electrode hole according to the pattern;
a silicon oxide film, a metal film on a selected surface portion of the phosphorous glass film, and on the surface of the semiconductor substrate exposed by the electrode hole.