Semiconductor device manufacturing: process – Chemical etching – Vapor phase etching
Reexamination Certificate
1999-09-28
2001-04-10
Booth, Richard (Department: 2812)
Semiconductor device manufacturing: process
Chemical etching
Vapor phase etching
C438S724000, C438S743000, C438S744000, C438S637000, C438S638000, C438S639000, C438S640000
Reexamination Certificate
active
06214744
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method for manufacturing a semiconductor device where a contact hole is perforated in an insulating layer formed on a refractory metal layer.
2. Description of the Related Art
In a prior art method for manufacturing a semiconductor device, an insulating layer is formed on a refractory metal layer, and a contact hole is perforated in the insulating layer by a dry etching process using CF
4
gas. This will be explained later in detail.
In the prior art method, however, the etching rate ratio of the insulating layer to the refractory metal layer by the dry etching process using CF
4
gas is not sufficiently large. Therefore, the refractory metal layer is overetched. As a result, an electrode or a connection layer deposited on the refractory metal layer is easily separated therefrom, which increases a contact resistance therebetween.
In addition, if the power of the dry etching process is increased to increase the above-mentioned etching ratio, the throughput is decreased.
On the other hand, assume that an insulating layer is formed on active regions of a semiconductor substrate. In this case, when the insulating layer is overetched, the active regions of the semiconductor substrate are exposed to CF
3
+
ions which causes damage thereof.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a dry etching process exhibiting a high etching ratio of an insulating layer to an refractory metal layer in a method for manufacturing a semiconductor device.
According to the present invention, in a method for manufacturing a semiconductor device, an insulating layer is formed on a refractory metal layer, and a contact hole is perforated in the insulating layer by a dry etching process using an etching gas. The etching gas includes one of:
a mixture gas of fluorocarbon and hydrogen;
a mixture gas of hydrofluorocarbon and hydrogen;
a gas of hydrofluorocarbon; and
a fluorocarbon gas except for CF
4
.
The refractory metal layer is preferably made of tungsten, tungsten alloy, molybdenum or molybdenum alloy. Such tungsten alloy is titanium tungsten, tungsten silicide, tungsten nitride or the like, and such molybdenum alloy is molybdenum nitride, molybdenum titanium or the like. Also, the refractory metal layer can be made of two or more layers.
The insulating layer is preferably made of silicon oxide, silicon nitride or silicon oxide nitride.
The fluorocarbon gas is aliphatic hydrocarbon gas where hydrogen is replaced by fluorine, such as CF
4
gas, C
2
F
6
gas or C
3
F
8
gas. The flow rate ratio of H
2
gas to fluorocarbon gas plus H
2
gas is about 10 to 50 percent, and preferably, 30 to 40 percent.
The hydrofluorocarbon gas is aliphatic hydrocarbon gas where hydrogen is replaced by a part of fluorine, such as CHF
3
gas, CH
2
F
2
gas or C
2
HF
5
gas.
The fluorocarbon gas except for CH
4
is preferably C
3
H
8
gas.
REFERENCES:
patent: 4522681 (1985-06-01), Gorowitz et al.
patent: 4582563 (1986-04-01), Hazuki et al.
patent: 5702982 (1997-12-01), Lee et al.
patent: 62-150889 (1987-07-01), None
patent: 64-24466 (1989-01-01), None
patent: 2-280326 (1990-11-01), None
patent: 4-291925 (1992-10-01), None
patent: 6-112229 (1994-04-01), None
Booth Richard
Hayes Soloway Hennessey Grossman & Hage PC
NEC Corporation
Zarneke David A.
LandOfFree
Method for manufacturing semiconductor device capable of... 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 for manufacturing semiconductor device capable of..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method for manufacturing semiconductor device capable of... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2541796