JPH06120166A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To prepare a semiconductor device which can suppress the generation of a void due to a TiN film of the upper layer of an Al-Si-Cu film, or, to be specific, to provide the forming of wiring. CONSTITUTION:A PSG film 4 is formed into 2 a pattern on a semiconductor substrate 5, a TiN film is deposited, and, after heat treatment in a nitrogen atmosphere, an Al film 6 is deposited. Next, a TiN film is deposited and subjected to heat treatment in a nitrogen atmosphere. Because the TiN film of the uppermost layer is completely nitrified through heat treatment, the generation of a void in the Al film 6 side wall due to an unreacted Ti is suppressed, and the wiring of a semiconductor device of high reliability is obtained.

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 a method of forming wiring of a semiconductor device formed on a semiconductor substrate.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 3, a semiconductor device has been used as a light antireflection film at the time of patterning an Al thin film having a predetermined film thickness in order to electrically connect the semiconductor elements. The TiN film and the Al thin film and the Ti and TiN films which suppress the reaction between the Al thin film and the semiconductor substrate.

A PSG film 4 is patterned on a semiconductor substrate 5, and two layers of a Ti film 1 and a TiN film 2 are formed so as to come into contact with the semiconductor substrate 5 through a contact hole provided in the PSG film 4. Wiring having a structure is formed (FIG. 3A). After that, heat treatment is performed in an N ₂ atmosphere (FIG. 3B), the Al—Si—Cu film 6 is deposited (FIG. 3C), and then the TiN film 7 is deposited (FIG. 3).
(D)).

Conventional TiN / Al-Si-Cu / TiN
Ti / T under the Al-Si-Cu film in the Ti / Ti film
The i film was used to suppress the reaction between the Al-Si-Cu film and the semiconductor substrate (contact). Also Al-
The TiN film on the upper layer of the Si-Cu film is used as an antireflection film when patterning the Al-Si-Cu film, and the uppermost TiN film is not heat-treated.

[0005]

In the wiring formed by the conventional method of manufacturing a semiconductor device, the diameter of the Al-Si-Cu film, which is caused by the unreacted Ti in the upper layer of the Al-Si-Cu film, is about the same. There is a problem in that minute voids of 10 to 100 nm are generated and the reliability of the Al-Si-Cu film as a wiring material is significantly deteriorated.

It is an object of the present invention to form Ti when connecting wirings for connecting integrated circuit elements formed on a semiconductor substrate.
It is an object of the present invention to provide a method for manufacturing a semiconductor device capable of suppressing the generation of voids on the side walls of Al—Si—Cu due to unreacted Ti that has not been converted to N.

[0007]

A method of manufacturing a semiconductor device according to a first aspect of the present invention is a method of forming wirings for connecting integrated circuit elements formed on a semiconductor substrate, wherein the wiring is formed on the semiconductor substrate. A step of forming a contact hole in the insulating film, and a step of forming a wiring having a two-layer structure including a Ti film as a first layer film and a TiN film as a second layer film so as to be in contact with the semiconductor substrate through the contact hole. And 2
A step of heat-treating the semiconductor substrate on which the wiring of the layer structure is formed in a nitrogen atmosphere, and Al--Si--Cu as a third layer film
Film, a step of forming a TiN film as a fourth layer film on the second layer film, and a step of heat-treating the semiconductor substrate on which the wiring of the four-layer structure is formed in a nitrogen atmosphere.

A method of manufacturing a semiconductor device according to a second aspect of the present invention is a method of forming a wiring for connecting an integrated circuit element formed on a semiconductor substrate, wherein the insulating film formed on the semiconductor substrate is formed. A step of forming a contact hole, a step of forming a wiring having a two-layer structure composed of a Ti film as a first layer film and a TiN film as a second layer film so as to contact the semiconductor substrate through the contact hole, and two layers It is characterized in that it has a step of heat-treating a semiconductor substrate on which a wiring having a structure is formed in a nitrogen atmosphere, and a step of forming an Al-Si-Cu film as a third layer and a WSi film as a fourth layer film. It

[0009]

DETAILED DESCRIPTION OF THE INVENTION Reference will now be made to the drawings of the present invention. Figure 1
FIG. 6A is a cross-sectional view of the semiconductor substrate shown in order of steps for explaining the method for manufacturing the semiconductor device according to the embodiment of the present invention.

First, as shown in FIG. 1A, a PSG film 4 is formed on a semiconductor substrate 5 by patterning.
A wiring having a two-layer structure of the Ti film 1 and the TiN film 2 is formed so as to come into contact with the semiconductor substrate 5 through the contact hole provided in the SG film 4.

Thereafter, as shown in FIG. 1B, heat treatment is performed in an N ₂ atmosphere. Then, as shown in FIG.
The Al-Si-Cu film 6 is deposited. Next, as shown in FIG. 1D, a TiN film 2 is deposited, and then heat treatment (600 ° C. or less, 30 seconds or more) is performed in an N ₂ atmosphere at a temperature at which Al does not melt.

In the first embodiment described above, after the TiN films of four layers are deposited, the heat treatment is performed in the N ₂ atmosphere which has not been conventionally performed, so that unreacted Ti that is not completely nitrided is eliminated. Diameter 10-100 with unreacted Ti
This has the effect that minute voids of nm are unlikely to occur on the side wall of the Al-Si-Cu film 6.

2A to 2D are cross-sectional views of a semiconductor substrate, which are shown in the order of steps for explaining a method of manufacturing a semiconductor device according to another embodiment of the present invention. As shown in FIG. 2A, the PSG film 4 is patterned on the semiconductor substrate 5.
Semiconductor substrate 5 through the contact hole provided in G film 4
A wiring having a two-layer structure of a Ti film 1 and a TiN film 2 is formed so as to come into contact with. Then, as shown in FIG. 2B, heat treatment is performed in an N ₂ atmosphere. Then Fig. 2
As shown in (c), an Al-Si-Cu film 6 is deposited. Next, as shown in FIG. 2D, a WSi film is deposited.

In the second embodiment, since the WSi film is used for the fourth layer, there is an effect that voids due to Ti do not occur on the side wall of the Al-Si-Cu film 6 and that the Al loss resistance is strong. .

[0015]

As described above, according to the present invention, A
Since the upper layer of the 1-Si-Cu film is a TiN film or a WSi film that has been heat-treated in an N ₂ atmosphere, unreacted Ti that has not been converted to TiN causes the occurrence of voids on the side walls of Al-Si-Cu. Has the effect of being suppressed. In the TiN structure of the uppermost layer that has not been heat-treated in the conventional N ₂ atmosphere, the occurrence rate of voids occurs with a probability of about 50%, but with the above structure, it can be suppressed to zero.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a semiconductor substrate shown in order of steps for explaining an embodiment of the present invention.

FIG. 2 is a vertical cross-sectional view of a semiconductor substrate shown in the order of steps for explaining another embodiment of the present invention.

FIG. 3 is a vertical cross-sectional view of a semiconductor substrate, which is shown in order of steps for explaining a conventional method for manufacturing a semiconductor device.

[Explanation of symbols]

 1 Ti film 2 TiN film 3 WSi film 4 PSG film 5 Semiconductor substrate 6 Al-Si-Cu film

Claims (2)

[Claims] 1. A method for forming a wiring for connecting an integrated circuit element formed on a semiconductor substrate, the method comprising: forming a contact hole in an insulating film formed on the semiconductor substrate; and a semiconductor through the contact hole. A step of forming a two-layer structure wiring made of a Ti film as a first layer film and a TiN film as a second layer film so as to be in contact with the substrate, and a semiconductor substrate having the two-layer structure wiring formed thereon is heat-treated in a nitrogen atmosphere. And a step of forming an Al—Si—Cu film as a third layer film and a TiN film as a fourth layer film on the second layer film, and a semiconductor substrate on which the wiring of the four-layer structure is formed in a nitrogen atmosphere. And a step of performing heat treatment therein. 2. A method of forming a wiring for connecting an integrated circuit element formed on a semiconductor substrate, the method comprising: forming a contact hole in an insulating film formed on the semiconductor substrate; and a semiconductor through the contact hole. A step of forming a two-layer structure wiring made of a Ti film as a first layer film and a TiN film as a second layer film so as to be in contact with the substrate, and a semiconductor substrate having the two-layer structure wiring formed thereon is heat-treated in a nitrogen atmosphere. And a step of forming an Al-Si-Cu film as the third layer and a WSi film as the fourth layer film.