Method of forming a patterned tungsten damascene interconnect

Details Method of forming a patterned tungsten damascene interconnect Method of forming a patterned tungsten damascene interconnect

2002-12-12

2004-08-24

Kielin, Erik (Department: 2813)

Semiconductor device manufacturing: process

Coating with electrically or thermally conductive material

To form ohmic contact to semiconductive material

C438S628000, C438S629000, C438S648000, C438S675000, C438S685000

Reexamination Certificate

active

06780764

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention generally relates to a method for forming a semiconductor device, and more particularly, the present invention relates to a method for forming titanium and titanium nitride for using as adhesion layer.
This application is a counterpart of Japanese application Serial Number 14439/2000, filed Jan. 24, 2000, the subject matter of which is incorporated herein by reference.
2. Description of the Related Art
In general, as high-integration advances, tungsten interconnection utilized tungsten has been a focus of constant attention because step coverage is fine.
FIG.
1
A through
FIG. 1D
are cross-sectional views showing a method for forming a semiconductor device according to a conventional art. As shown in
FIG. 1A
, an insulating film
2
having a contact hole
3
is formed on a silicon substrate
1
. A part of the silicon substrate
1
is exposed from the contact hole
3
.
As shown in
FIG. 1B
, using CVD (Chemical Vapor Deposition) technique, a titanium film
4
is formed on the insulating film
2
and the exposed silicon substrate
1
surface. Here, the CVD technique is carried out introducing titanium tetrachloride and hydrogen gas. Then, the titanium film
4
is treated with nitrogen plasma ion. Therefore, the nitrogen plasma ion is generated using ammonia, and the titanium film
4
reacts with the nitrogen plasma ion. Then, a titanium nitride film
5
is formed on the plasma treated titanium film
4
using the CVD technique. Here, the CVD technique is carried out introducing titanium tetrachloride and ammonia gas.
As shown in
FIG. 1C
, for decreasing low resistance, the titanium nitride film
5
is annealed in the atmosphere of ammonia. Then, a tungsten film
6
is formed on the annealed titanium nitride film
5
. Then, the tungsten film
6
is etched back. As a result, the tungsten film
6
is buried in the contact hole
3
.
As described above, the plasma treating of ammonia is carried to increase adhesion between the titanium film
4
and a titanium nitride film.
However, since the plasma treating of ammonia has a high nitriding speed for titanium, the titanium film is completely converted the titanium nitride film. Besides, the silicon substrate
1
surface under the titanium film is also nitridized. Therefore, a silicon nitride is formed on the silicon substrate
1
surface. As a result, a contact resistance of the tungsten interconnection in a contact hole, is increased.
It is desired to decrease a contact resistance of the tungsten interconnection in a contact hole.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a method for forming a semiconductor device that can decrease a contact resistance of the tungsten interconnection in a contact hole.
According to one aspect of the present invention, for achieving the above object, there is provided a method for forming a semiconductor device comprising: providing a semiconductor substrate; forming an insulating film having a opening; forming a titanium film so as to extend from the semiconductor substrate in the opening to the insulating film surface; plasma treating the titanium film with a mixed gas of hydrogen and nitrogen; and forming a titanium nitride on the titanium film.


REFERENCES:
patent: 5279857 (1994-01-01), Eichman et al.
patent: 5308655 (1994-05-01), Eichman et al.
patent: 5591672 (1997-01-01), Lee et al.
patent: 5975912 (1999-11-01), Hillman et al.
patent: 6051281 (2000-04-01), Kobayashi et al.
patent: 6136690 (2000-10-01), Li
patent: 6309966 (2001-10-01), Govindarajan et al.

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