Browse Prior Art Database

Selective and Directional Etching of Polysilicon and WSi(2)

IP.com Disclosure Number: IPCOM000049453D
Original Publication Date: 1982-Jun-01
Included in the Prior Art Database: 2005-Feb-09
Document File: 2 page(s) / 47K

Publishing Venue

IBM

Related People

Bennett, RS: AUTHOR [+2]

Abstract

This article relates generally to the etching of polysilicon and silicide in a flexible diode reactor and more specifically to the selective and directional etching of polysilicon and tungsten silicide in a flexible diode reactor without undercutting during overetching and without the use of a toxic and/or corrosive etching gas.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 59% of the total text.

Page 1 of 2

Selective and Directional Etching of Polysilicon and WSi(2)

This article relates generally to the etching of polysilicon and silicide in a flexible diode reactor and more specifically to the selective and directional etching of polysilicon and tungsten silicide in a flexible diode reactor without undercutting during overetching and without the use of a toxic and/or corrosive etching gas.

These etch characteristics are obtained by dividing RF power in a flexible diode reactor and using CCl(2)F(2) as the etching gas.

If reactive ion etching (RIE) in CCl(2)F(2) is carried out, etching is directional but not selective (n polysilicon to silicon dioxide etch rate ratio is only 2 to 1). If plasma etching in CCl(2) F(2) is carried out, etching is selective but not directional.

In the present process, directional etching with an n/+/ polysilicon to silicon dioxide etch rate ratio of 15 to 1 may be obtained by dividing RF power between the two electrodes of a flexible diode reactor similar to that shown in the figure.

Etching is carried on 2-1/4 inch wafers which are recessed in the aluminum substrate electrode. The latter is coated with resist. CC1(2) F(2) is introduced into the reactor at 5 sccm to provide a pressure of 25 millitorr. One hundred and forty watts of RF power is applied to a 12-inch diameter perforated top electrode and 60 watts of RF power is applied to a 12-inch diameter water cooled substrate electrode.

The following etch rates have been obtained under t...