Method of forming gate electrode in semiconductor device

Details Method of forming gate electrode in semiconductor device Method of forming gate electrode in semiconductor device

1999-12-14

2001-12-25

Wilczewski, Mary (Department: 2822)

Semiconductor device manufacturing: process

Coating with electrically or thermally conductive material

Insulated gate formation

C438S592000

Reexamination Certificate

active

06333250

ABSTRACT:

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 a tungsten gate electrode.
2. Description of the Related Art
In general, a polysilicon layer is used for a gate electrode material of a MOSFET. However, as high integration of a semiconductor device, the line width of the gate electrode is significantly reduced. Therefore, in case of a polysilicon gate electrode, it is difficult to obtain low resistivity required for the high integration device. Accordingly, a tungsten layer has been researched as the gate electrode material, recently.
In case of a tungsten gate electrode, gate re-oxidation process is generally performed after forming a tungsten gate electrode, for improving the reliability of a gate insulating layer. However, when performing the gate re-oxidation process, the side wall of a tungsten layer
5
is excessively oxidized due to its fast oxidation rate, to occur abnormal oxidation of the tungsten layer
5
, as shown in
FIG. 1
, thereby deteriorating properties and reliability of a device. In
FIG. 1
, reference numbers
1
,
2
,
3
and
4
indicate a semiconductor substrate, a gate oxide layer, a polysilicon layer and a diffusion barrier layer, respectively. Furthermore, reference numbers
6
and
7
indicate a mask pattern used for etch barrier and a thermal oxidation layer grown by abnormal oxidation, respectively.
To solve the above problem, a method of forming a tungsten gate electrode using a spacer, is suggested. Referring to
FIG. 2
when performing etch process to form a gate electrode, the tungsten layer
5
and the diffusion barrier layer
4
are etched and a spacer
8
is then formed on the side wall of the etched tungsten layer
5
and diffusion barrier layer
4
. Therefore, when performing subsequent gate re-oxidation process, abnormal oxidation is not occurred on side wall of the tungsten layer
5
.
Thereafter, as not shown in
FIG. 2
, the polysilicon layer
3
and the gate oxide layer
2
are etched to form a gate electrode. Next, LDD ion implantation and gate re-oxidation processes are performed, respectively.
As described above, when performing gate re-oxidation process, abnormal oxidation is not occurred on side of the tungsten layer
5
by the spacer
8
. However, since the width of the gate electrode increases due to the spacer
6
, it is difficult to apply high integration semiconductor device required for a gate electrode with fine line width.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a method of forming a gate electrode in a semiconductor device which can prevent abnormal oxidation of a tungsten layer without increasing the line width of the gate electrode by etching a tungsten layer and a diffusion barrier layer to the width of a spacer prior to forming the spacer, for solving the problems in the conventional art.
To accomplish this above object, a method of forming a gate electrode in a semiconductor device according to the present invention includes steps of: forming a gate oxide layer, a polysilicon layer, a diffusion barrier layer, a metal layer and a mask layer on a semiconductor substrate, in sequence; patterning the mask layer, the metal layer and the diffusion barrier layer to the first width; patterning the mask layer, the metal layer and the diffusion barrier layer having the first width to a second width by wet etching; forming a spacer on the side walls of the mask layer, the metal layer and the diffusion barrier layer having the second width; and patterning the polysilicon layer and the gate oxide layer using the mask layer and the spacer as an etch barrier.
According to the present invention, since a spacer is formed on the sides a metal layer and a diffusion barrier layer after etching the metal layer and the diffusion barrier layer to the width of the spacer, it is possible to obtain a gate electrode with fine line width and abnormal oxidation is not occurred on the sides of the metal layer.


REFERENCES:
patent: 4404732 (1983-09-01), Andrade
patent: 4740826 (1988-04-01), Chatterjee
patent: 4929567 (1990-05-01), Park et al.
patent: 5071788 (1991-12-01), Joshi
patent: 5112765 (1992-05-01), Cederbaum et al.
patent: 5116774 (1992-05-01), Huang et al.
patent: 5212400 (1993-05-01), Joshi
patent: 5599725 (1997-02-01), Dorleans et al.
patent: 5633522 (1997-05-01), Dorleans et al.
patent: 5688706 (1997-11-01), Tseng
patent: 5789312 (1998-08-01), Buchanan et al.
patent: 5858867 (1999-01-01), Hsia et al.
patent: 5925918 (1999-07-01), Wu et al.
patent: 5998290 (1999-12-01), Wu et al.
patent: 6037228 (2000-03-01), Hsu
patent: 6075274 (2000-06-01), Wu et al.
patent: 6107171 (2000-08-01), Tsai
patent: 6165883 (2000-12-01), Hiura
patent: 6235621 (2001-05-01), Jung et al.
patent: 6236093 (2001-05-01), Hiura
patent: 55030867 (1980-03-01), None
patent: 60015920 (1985-01-01), None
patent: 61241974 (1986-10-01), None
patent: 01125985 (1989-05-01), None
patent: 01175257 (1989-07-01), None
patent: 01187871 (1989-07-01), None
patent: 01207971 (1989-08-01), None
patent: 01207972 (1989-08-01), None
patent: 01207973 (1989-08-01), None
patent: 01251758 (1989-10-01), None
patent: 02007552 (1990-01-01), None
patent: 02026074 (1990-01-01), None
patent: 02077162 (1990-03-01), None
patent: 02129917 (1990-05-01), None
patent: 04336468 (1992-11-01), None
patent: 07263680 (1995-10-01), None
patent: 10135452 (1998-05-01), None

Affiliated with

Also associated with

Rating

Method of forming gate electrode in semiconductor device does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Method of forming gate electrode in semiconductor device, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method of forming gate electrode in semiconductor device will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2587651