JPH02270347A - Manufacture of semiconductor device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to improvements in microfabrication technology for semiconductor devices having two-layer wiring.

[Prior Art] FIGS. 2(a) to 2(e) are cross-sectional views showing the steps of a conventional method for manufacturing a semiconductor device.

In the figure, (5) is a semiconductor substrate, (4) is a first Al wiring, and (2) is an interlayer oxide film, which is a resist (1).

and a pattern is formed. Also, (7) is layer (7)
is a polymer generated during anisotropic dry etching of the interlayer oxide film (2), and (8) is a disconnection of the second Al film that occurs when forming the second Al wiring (6).

Next, the effect will be explained. As shown in FIG. 2(a), a first Al wiring (4) and an interlayer oxide film (2) are formed on a semiconductor substrate (5), and a resist (1) is patterned.

Next, as shown in FIG. 2(b), by anisotropic dry etching, the interlayer oxide film (
2) is processed to form a through hole. here,
Over-etching is performed to prevent the interlayer oxide film (2) from remaining, but at this time, the underlying Al wiring (4) is scraped off by the fluorine thread etching gas, leaving a polymer (4) on the side wall of the through hole. 7) is formed.

Next, FIG. 2(C) is a cross section after removing the resist (1) with oxygen plasma, but the polymer (7) is not removed at all and remains as a residue.

FIG. 2(d) is a cross-sectional view of the second Al wiring (6) formed, and since polymer (7) remains in the through hole, disconnection (8) of the second Al film occurs.

[Problem to be solved by the invention] Since the conventional semiconductor device is configured as described above,
When forming a through hole by anisotropic dry etching, the first Al wiring on the base is etched by the fluorine thread gas, and a polymer, which is a fluoride containing Al, is formed on the side wall of the through hole. The second Al
There were problems such as disconnection during wiring film formation.

This invention was made in order to solve the above-mentioned problems, and when forming a through hole by anisotropic dry etching, it eliminates the generation of polymer that adheres to the side wall of the through hole and makes it easier to use in the next process. An object of the present invention is to obtain a method for manufacturing a semiconductor device that prevents disconnection of the second Al film.

[Means for Solving the Problems] A method for manufacturing a semiconductor device according to the present invention is characterized in that amorphous silicon is provided on the 181st wiring, and through holes are formed in an overlying plasma oxide film or the like by anisotropic dry etching. In the case of forming by etching, the amorphous silicon is used as a stopper film in anisotropic dry etching.

[Function] In the method of manufacturing a semiconductor device according to the present invention, amorphous silicon is provided on the first Al wiring, and a through hole for the purpose of bonding with the second Al wiring is formed in a plasma oxide film, which is an interlayer insulating film, by anisotropic drying. When forming by etching, by using the amorphous silicon mentioned above as a stopper film in anisotropic dry etching, the generation of polymer generated during dry etching can be prevented and reliable A12 layer wiring technology can be achieved. obtain.

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings. 1st
Figures (a) to (e) are cross-sectional views showing the steps of a method for manufacturing a semiconductor device. In the figure (1) and (2).

(4) to (6) are the same as those shown in the conventional example shown in FIG. 2, so their explanation will be omitted. (3) is amorphous silicon.

Next, the effect will be explained. As shown in FIG. 1(a), a first Al wiring (4), amorphous silicon (3), and an interlayer oxide film (2) are formed on a semiconductor substrate (5), and a resist (1) is patterned.

Next, as shown in FIG. 1(b), the interlayer oxide film (2) is etched using the resist (1) as a mask material by anisotropic dry etching.
) is processed to form a through hole. Here, over-etching is performed to prevent the interlayer oxide film (2) from remaining, but the amorphous silicon (3) serves as an etching stopper film, and the sidewalls of the through-holes are coated with aluminum-containing polymer. There is no generation of

Next, the resist (1) was removed using oxygen plasma, and the result is shown in FIG. 1(C).

Figure 1(d) shows the amorphous silicon (3) in the through-hole area selectively removed by isotropic dry etching, and the underlying first Al wiring (4) is rarely etched. Therefore, no polymer is generated.

Next, FIG. 1(e) is a cross-sectional view of the second Al wiring (6) formed, and good step coverage of the second Al wiring (6) can be obtained.

In the above embodiment, amorphous silicon (1) was used as a stopper during anisotropic etching of the interlayer oxide film (2)
3) was used, but similar effects can be obtained with other materials such as Ti or TiN.

[Effects of the Invention] As described above, according to the present invention, amorphous silicon is configured as a stopper source in anisotropic etching of an interlayer oxide film. This has the effect of eliminating the generation of polymer adhering to the sidewalls, preventing disconnection of the second Al film in the next step, and providing a highly reliable semiconductor device.

[Brief explanation of drawings]

1(a) to 1(e) are cross-sectional views showing steps of a method for manufacturing a semiconductor device according to an embodiment of the present invention, and FIGS. 2(a) to 2(e)
(d) is a cross-sectional view showing the steps of a conventional semiconductor device manufacturing method. In the figure, (1) is the resist, (2) is the interlayer oxide film, (
3) is amorphous silicon, (4) is the first Al wiring,
(5) is a semiconductor substrate, and (6) is a second Al wiring. In addition, in the figures, the same reference numerals indicate the same or equivalent parts.

Claims (1)

[Claims] In a semiconductor device having two-layer Al wiring, amorphous silicon is provided on the first Al wiring, and a through hole for the purpose of bonding with the second Al wiring is formed in the plasma oxide film, which is an interlayer insulating film, by anisotropic dry etching. In the semiconductor device, the amorphous silicon is used as a stopper film in anisotropic dry etching, and the second Al wiring is formed after selectively removing the amorphous silicon in the through-hole portion in the next step. manufacturing method.