Semiconductor device manufacturing: process – Coating with electrically or thermally conductive material – To form ohmic contact to semiconductive material
Reexamination Certificate
1997-11-06
2001-02-06
Niebling, John F. (Department: 2812)
Semiconductor device manufacturing: process
Coating with electrically or thermally conductive material
To form ohmic contact to semiconductive material
C438S628000, C438S629000, C438S630000, C438S644000, C438S648000, C438S649000, C438S654000, C438S655000, C438S656000, C438S669000, C438S672000, C438S674000, C438S675000, C438S677000, C438S685000
Reexamination Certificate
active
06184130
ABSTRACT:
BACKGROUND OF THE INVENTION
(1) Field of the Invention
The invention relates to a method of metallization in the fabrication of integrated circuits, and more particularly, to a method of tungsten plug metallization in the manufacture of integrated circuits.
(2) Description of the Prior Art
Tungsten-plug metallization is widely used in the art for vertical interconnects of various metal layers in integrated circuit fabrication. A conventional tungsten chemical vapor deposition (W-CVD) process is illustrated in
FIG. 1. A
contact hole is opened in a dielectric layer
14
overlying a semiconductor substrate
10
. A glue layer
18
is deposited over the dielectric layer and within the contact opening. Typically, the glue layer, which is used as a nucleation layer for the CVD tungsten, comprises titanium nitride, 500 to 1500 Angstroms in thickness, with a thin titanium underlayer, 100 to 500 Angstroms, for adhesion. A tungsten layer
22
is then deposited by CVD and etched back, as shown in
FIG. 2
, to form the tungsten plug. However, this process if associated with high complexity and cost, high via resistance, and poor controllability of particulation. Moreover, the continuous scaling down of the contact hole size causes great difficulty in filling the contact hole.
U.S. Pat. No. 5,286,675 to Chen et al teaches a procedure for forming tungsten plugs including the conventional Ti/TiN as the glue layer and the use of reactive ion etching (RIE) to remove the tungsten layer to form the plug. U.S. Pat. No. 5,397,742 to Kim shows the use of a TiSi
2
glue layer overlying a Ti/TiN layer which is etched away after the tungsten plug is formed in order to remove tungsten residue.
SUMMARY OF THE INVENTION
A principal object of the present invention is to provide an effective and very manufacturable method of tungsten plug metallization.
Another object of the invention is to provide a method of tungsten plug metallization with reduced cost and complexity.
Yet another object is to provide a method of tungsten plug metallization with reduced glue layer thickness.
A still further object of the invention is to provide a method of tungsten plug metallization having improved contact resistance.
Yet another object is to provide a method of tungsten plug metallization using a silicide as a combined ohmic contact and glue layer.
Yet another object of the invention is to provide a method of tungsten plug metallization with reduced cost and complexity using a silicide as a combined ohmic contact and glue layer.
In accordance with the objects of this invention a new method of tungsten plug metallization using a silicide glue layer is achieved. Semiconductor device structures are provided in and on a semiconductor substrate. An insulating layer is provided covering the semiconductor device structures wherein a contact opening is made through the insulating layer to one of the semiconductor device structures. A silicide layer is deposited conformally over the surface of the insulating layer and within the contact opening as a combined ohmic contact and glue layer. In a first embodiment, a tungsten layer is deposited overlying the silicide layer. The tungsten layer not within the contact opening is removed to complete the formation of the tungsten plug metallization. In a second embodiment, the silicide layer not within the contact opening is selectively removed and a tungsten layer is selectively deposited overlying the silicide layer within the contact opening to complete formation of the tungsten plug metallization in the fabrication of an integrated circuit.
Also in accordance with the objects of this invention, an integrated circuit device having tungsten plug metallization using a silicide glue layer is described. Semiconductor device structures are formed in and on a semiconductor substrate. An insulating layer covers the semiconductor device structures. A patterned metal layer overlies the insulating layer. A tungsten plug extends through the insulating layer connecting the patterned metal layer with one of the semiconductor device structures. A silicide layer lies between the tungsten plug and the insulating layer and between the tungsten plug and the one of the semiconductor device structures wherein the silicide layer acts as an ohmic contact and glue layer.
REFERENCES:
patent: 5023201 (1991-06-01), Stanasolovich et al.
patent: 5030588 (1991-07-01), Hosaka
patent: 5183782 (1993-02-01), Onishi et al.
patent: 5286675 (1994-02-01), Chen et al.
patent: 5397742 (1995-03-01), Kim
patent: 5604158 (1997-02-01), Cadien et al.
Chen Hsueh-Chung
Ku Tzu-Kun
Lou Chine-Gie
Ackerman Stephen B.
Industrial Technology Research Institute
Niebling John F.
Pike Rosemary L.S.
Saile George O.
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