JPH05144812A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To provide the manufacturing method for a semiconductor device on which a metal film is formed on the upper part and the side wall of an aluminum or aluminum alloy wiring in an excellent controllable manner. CONSTITUTION:An aluminum film 13 and a titanium film 14 are successively formed on the oxide film 12 formed on a silicon substrate 11. Then, after an oxide film 15 has been formed, the oxide film 15, the titanium film 14 and the aluminum film 13 are etched successively using the wiring mask formed by photolithography. A TiW film 106 is formed thereon. The TiW film 16 is left on the side wall of the aluminum wiring 13 by conducting an overall etching treatment. Consequently, as an oxide film 15 is formed on the titanium film 14, the titanium film 14 is not exposed to etching when the TiW film 16 is etched.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a semiconductor device, and more particularly to a method for manufacturing a semiconductor device obtained by improving a method for forming metal wiring.

[0002]

2. Description of the Related Art Since the miniaturization of wiring has been advancing along with the high integration of semiconductor devices, aluminum
Wiring made of a silicon alloy has been problematic due to defects due to electromigration and stress migration. As a countermeasure, a structure in which a metal film is formed on the upper and side walls of a wiring made of an aluminum-silicon alloy is described in, for example, JP-A-60-193362 and JP-A-62-66628.

FIG. 3 shows a manufacturing process of this conventional semiconductor device. Here, a conventional method of manufacturing a semiconductor device will be described with reference to FIG. First, as shown in FIG. 3A, an aluminum film 33 and a titanium film 34 are sequentially formed on an oxide film (insulating film) 32 formed on a silicon substrate 31 by a sputtering method. Then, using a wiring mask (not shown) formed by photolithography (exposure technique), the titanium film 34 and the aluminum film 33 are sequentially etched to form a wiring pattern (see FIG. 3B). Next, a titanium film 35 is formed so as to cover the formed wiring pattern (see FIG. 3C). And
The entire surface of the substrate is etched back so that the titanium films 34 and 35 are left on the upper portions and the side walls of the aluminum wiring 33 (see FIG. 3D). As a result, the aluminum wiring 3
The top and side walls of 3 can be coated with titanium films 34 and 35.

[0004]

In the above-mentioned conventional technique, the metal film 35 shown in FIG. 3D (hereinafter referred to as "metal film 2") is left on the side wall of the aluminum wiring 33 during etching. Further, the metal film 34 (hereinafter referred to as “metal film 1” here) formed on the aluminum wiring 33 is exposed to etching. Metal film 1 and metal film 2
Even if the metal films made of different materials are used and the metal film 2 can be etched with a large etching selection ratio with respect to the metal film 1, there is an inconvenience that the reduction of the metal film 1 due to etching is unavoidable.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for manufacturing a semiconductor device, which is capable of improving the disadvantages of the prior art and forming a metal film for covering the upper portion and the side wall of a metal wiring with good controllability. is there.

[0006]

In the method of manufacturing a semiconductor device according to the present invention, a first conductive film and a second conductive film are sequentially formed on an insulating film formed on a semiconductor substrate, and a second conductive film is formed. A mask material film is formed on the conductive film, the mask material film, the second conductive film, and the first conductive film are sequentially etched with the same mask pattern to form a wiring pattern, and then the formed wiring is formed. A method of forming a third conductive film so as to cover the pattern and thereafter performing anisotropic etching so that the third conductive film is left on the sidewall of the first conductive film is adopted.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG.

FIG. 1 is a process diagram of a semiconductor manufacturing method according to an embodiment of the present invention. Here, a method of manufacturing a semiconductor device will be described with reference to FIG.

First, as shown in FIG. 1A, a first conductive film having a thickness of 0.6 μm is formed on an oxide film 12 as an insulating film formed on the surface of a silicon substrate 11 as a semiconductor substrate. An aluminum film 13 and a titanium film 14 as a second conductive film having a thickness of 0.1 μm are sequentially formed by a sputtering method. Further, an oxide film 15 as a mask material film is formed on the titanium film 14.

Next, a wiring pattern is formed by sequentially etching the oxide film 15, the titanium film 14, and the aluminum film 13 using a wiring mask (which is a mask at the time of etching) not shown formed by photolithography. (See FIG. 3B).

Then, T as a third conductive film having a thickness of 0.1 μm is formed so as to cover the formed wiring pattern.
The iW film 16 is formed by the sputtering method (see FIG. 3c).

Thereafter, by etching back the entire surface of the substrate so that the TiW film 16 is left on the side wall of the aluminum film 13, a desired wiring structure as shown in FIG. 3D is obtained.

According to this embodiment described above, since the oxide film 15 is formed on the titanium film 14, TiW
During the etching of the film 16, the titanium film 14 is not exposed to the etching and therefore the aluminum wiring 1
3 It is possible to almost certainly prevent the reduction of the titanium film 14 on the upper part, and thereby the metal film can be formed on the upper part and the side wall of the aluminum wiring with good control.

[0014]

Application Example FIG. 2 shows an application example of the present invention.
This application example corresponds to the aluminum film 13 in the above embodiment.
It is characterized in that a titanium film 17 is formed underneath. As a result, in this application example, the aluminum film, that is, the aluminum wiring 13 is connected to the barrier metal (titanium film
5, a structure surrounded by the TiW film 16 and the titanium film 17) can be obtained.

[0015]

As described above, according to the present invention, on the second conductive film (metal film) formed in close contact with the upper part of the metal wiring formed of the first conductive film (usually an aluminum film). Since a mask material film (protective film) is formed on the surface, when anisotropic etching is performed to leave the metal film on the sidewall of the metal wiring,
The metal film formed in close contact with the upper portion of the metal wiring is not etched. For this reason, it is possible to provide an unprecedented excellent method of manufacturing a semiconductor device in which the metal film on the metal wiring can be formed with good control.

[Brief description of drawings]

FIG. 1 is an explanatory view showing a process of an embodiment of a semiconductor manufacturing method of the present invention.

FIG. 2 is an explanatory diagram showing an application example of the present invention.

FIG. 3 is an explanatory view showing steps of a conventional semiconductor manufacturing method.

[Explanation of symbols]

 11 Silicon substrate as a semiconductor substrate 12 Oxide film as an insulating film 13 Aluminum film as a first conductive film 14 Titanium film as a second conductive film 15 Oxide film as a mask material film 16 As a third conductive film TiW film

Claims (1)

[Claims] 1. A first conductive film and a second conductive film are sequentially formed on an insulating film formed on a semiconductor substrate, and a mask material film is formed on the second conductive film. The mask material film, the second conductive film, and the first conductive film are sequentially etched from above with the same mask pattern to form a wiring pattern, and then a third wiring pattern is formed so as to cover the formed wiring pattern. A method of manufacturing a semiconductor device, comprising forming a conductive film, and thereafter performing anisotropic etching so as to leave the third conductive film on a sidewall of the first conductive film.