JPH0318025A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To make it possible po remove an insulating film without damages such as scraping of the surface of a substrate and causing of crystal defects by using a silicon oxide film containing carbon as impurities as an interlayer insulating film between wirings, and forming a protecting film on the surface of a silicon substrate in dry etching. CONSTITUTION:A silicon oxide film 12 containing carbon as impurities is deposited on a silicon substrate 11. A pattern 13 of a photoresist film is formed on the silicon oxide film. Then, the silicon oxide film 12 is removed by dry etching, and a pattern is formed. At this time, particles 14 of carbon incorporated in the silicon oxide film 12 as impurities flow out into the atmosphere of the system, and polymerization reaction occurs. Thus, macromolecular-state protecting film 15 containing carbon is formed on the surface of the silicon substrate 11. When the macromolecular-state protecting film 15 is deposited on the surface of the silicon substrate 11 in this way, the etching selecting ratio between the silicone oxide film 12 and the silicon subsstrate 11 as a ground can be improved. Thus, the interlayer insulating film can be selectively removed without damages on the surface of the silicon substrate.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a semiconductor having an interlayer insulating film on one main surface of a silicon substrate that can be removed by a dry etching process without damaging the silicon substrate during contact formation. The present invention relates to a method of manufacturing the device.

Conventionally, as shown in FIG. 2, after forming a silicon oxide film 42 as an interlayer insulating film on one main surface of a silicon substrate 41 (a
), a pattern is formed with the photoresist film 43 (b), and the silicon oxide film 42 is further removed by dry etching using a gas such as CHF3 to form a pattern (c), and after the photoresist film 43 is removed (d ), aluminum wiring 4
A method (e) of forming 6 is known.

Problems to be Solved by the Invention Conventionally, as shown in FIG. 2, when removing a silicon oxide film 22 used as an interlayer insulating film by dry etching,
The etching selectivity between the silicon oxide film and the underlying silicon substrate has been determined by conditions such as the pressure in the etching gas reaction system and RF power (applied high frequency power). However, in this case, the dry etching selectivity (SiO2/Si) between the silicon substrate 21 and the silicon oxide film 22
The problem is that when the silicon oxide film 22 is removed by dry etching, the silicon substrate 2l is also damaged by being scraped off at the same time.

An object of the present invention is to realize a semiconductor device including an insulating film that can be removed with a high selectivity with respect to the underlying silicon substrate.

Means for Solving the Problems In order to achieve the above object, the present invention uses a silicon oxide film containing carbon as an impurity in place of the conventional silicon oxide film as an interlayer insulating film.

In dry etching using fluorocarbon-based gases, a polymeric protective film is deposited on the silicon substrate surface during the dry etching process to improve the etching selectivity between the silicon oxide film and the underlying silicon substrate. This is well known. This is because carbon and fluorine contained in the etching gas cause a polymerization reaction on the silicon substrate surface. At this time, it is also known that when the C/F ratio of the etching gas is high, the reaction rate of the polymerization reaction increases.

With the configuration of the present invention, carbon contained in the silicon oxide film flows out into the reaction system during the dry etching process. Therefore, the C/F ratio of the reaction system becomes high, and the polymerization reaction of the polymeric protective film on the surface of the underlying silicon substrate is promoted.

This protective film protects the silicon substrate surface from dry etching, improves the etching selectivity between the silicon oxide film and the silicon substrate, and prevents damage to the underlying silicon substrate surface. Only the film can be removed.

EXAMPLES Hereinafter, examples of the present invention will be described with reference to the drawings.

FIG. 1 shows a first embodiment of the present invention. First, a silicon oxide film 12 containing carbon as an impurity is deposited on a silicon substrate 11 by the CVD method (a). Next, a pattern 13 of a photoresist film is formed on the silicon oxide film 12 (b).

Next, the silicon oxide film 12 is removed by dry etching to form a pattern. At this time, carbon particles 14 contained as impurities in the silicon oxide film 12 flow out into the atmosphere of the system, cause a polymerization reaction, and form a polymeric protective film 15 containing carbon on the silicon substrate surface. (C).

Next, the photoresist film 13 and the protective film 15 are removed by ashing, cleaning, etc. (d).

Furthermore, aluminum wiring 16 is formed on the silicon substrate and silicon oxide film by sputtering or the like (e).

By the above method, an interlayer insulating film formed using a known technique can be selectively removed without damaging the silicon substrate surface.

In the above embodiment, an insulating film is formed on a silicon substrate, but the silicon substrate may be a polycrystalline silicon film. In addition, we have assumed that silicon oxide containing carbon as an impurity is formed in the interlayer insulating film. Silicon oxide containing oxides may also be used.

Effects of the Invention As described above, the present invention uses a silicon oxide film containing carbon as an impurity for the interlayer insulating film of wiring, thereby forming a protective film on the silicon substrate surface during the dry etching process and scraping the silicon substrate surface. , it is possible to remove the insulating film without causing damage such as crystal defects.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional process flow diagram of an embodiment for realizing a cross-sectional structure according to the present invention, and FIG. 2 is a cross-sectional process flow diagram of a conventional example. 11...Silicon substrate, 12...Silicon oxide film containing carbon as an impurity, 13...
Photoresist film, 14... Carbon particles leaked into the reaction system during the dry etching process, 15... Protective film deposited during the dry etching process, 16... Aluminum wiring, 21 ...Shinocon board, 22...
・Silicon oxide film, 23... Photoresist film, 24... Silicon particles removed by etching, 25... Silicon substrate portion damaged during dry etching, 26 ...Aluminum wiring.

Claims (3)

[Claims] (1) A step of depositing a silicon oxide film containing carbon as an impurity on one main surface of a silicon substrate as an interlayer insulating film for wiring, and a step of patterning a photoresist on the silicon oxide film containing carbon as an impurity. and a step of patterning a silicon oxide film containing carbon as an impurity by dry etching. (2) The method for manufacturing a semiconductor device according to claim 1, wherein the interlayer insulating film is a silicon oxide film containing oxides of carbon and phosphorus as impurities. (3) The method of manufacturing a semiconductor device according to claim 1, wherein the interlayer insulating film is a silicon oxide film containing oxides of carbon, phosphorus, and boron as impurities.