Method of etching a layer in a semiconductor device

Details Method of etching a layer in a semiconductor device Method of etching a layer in a semiconductor device

1998-03-31

2001-03-13

Utech, Benjamin L. (Department: 1765)

Semiconductor device manufacturing: process

Chemical etching

Combined with coating step

C438S702000, C438S706000, C438S710000, C438S714000, C438S719000

Reexamination Certificate

active

06200902

ABSTRACT:

BACKGROUND OF THE INVENTION
The present invention relates to a method of forming a semiconductor device, and more particularly to a method of dry etching a silicon layer to make a groove.
It is a well-known etching method to etch a polysilicon layer by using a resist as a mask. Recently, it has become a requirement to complete the etching more quickly. The polysilicon layer is therefore etched using the resist as a mask by using an etching gas which has low selectivity against the resist to remove the polysilicon quickly as a first etching step before the resist is completely removed from polysilicon. As such, a resist is etched at the same time as the polysilicon. Then, as a second step, the polysilicon is etched with using the remaining resist as a mask by using an etching gas which has high selectivity against the resist. As such in the second step, the polysilicon is etched almost without etching the resist. Thus etching is achieved by the two step process etching. However, during the first etching step, the etching of the resist results in particulate etched resist which is re-deposited (settles) on the surface of the polysilicon. Therefore a problem occurs in that the polysilicon is not properly etched to the desired shape because of the re-deposited resist found on the polysilicon as a result of the first etching step just prior to the second etching step, acting as a mask to the second etching step.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a method of etching a polysilicon layer properly and efficiently to a desired shape regardless of any re-deposited resist existing on the polysilicon layer.
An etching method according to the present invention comprising the steps of: etching with a first etching gas a first portion of a layer and a resist film, using the resist film as a mask, thereby forming an re-deposited etched particulate resist film, which is caused by etching said resist film, on a surface of said layer; removing said re-deposited etched particulate resist film by using a second etching gas, and etching a second portion of said layer by using a third etching gas.
An etching method for a silicon layer according to the present invention is directed in one embodiment having one portion of a polysilicon layer formed over a substrate and another portion of a polysilicon layer buried into a groove. As a first step, the first portion of the polysilicon layer (other than the another portion in the groove) is etched by a dry etching method using a Cl
2
/HBr-based gas. Next, as a second step, a etched resist particulate film having accumulated in the groove by etching at the first step is etched by a dry etching method using a Cl
2
/HBr/O
2
-based gas. Then, as a third step, the remaining another portion of the polysilicon layer in the groove is etched by a dry etching method using an HBr/O
2
-based gas.


REFERENCES:
patent: 5017977 (1991-05-01), Richardson
patent: 5297082 (1994-03-01), Lee
patent: 5413966 (1995-05-01), Schoenborn
patent: 5414287 (1995-05-01), Hong
patent: 5522966 (1996-06-01), Komura et al.
patent: 5568422 (1996-10-01), Fujiwara
patent: 5698072 (1997-12-01), Fukada
patent: 5843226 (1998-12-01), Zhao et al.
patent: 5-243188 (1993-09-01), None
patent: 6-029257 (1994-02-01), None
patent: 7-335614 (1995-12-01), None
patent: 8-306672 (1996-11-01), None
patent: 9-069511 (1997-03-01), None

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