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THE CONTROL OF PLASMA ETCH SELECTIVITIES VIA OXYGEN ADDITION TO CHLORINE-BASED PLASMAS

IP.com Disclosure Number: IPCOM000005534D
Original Publication Date: 1984-Apr-01
Included in the Prior Art Database: 2001-Oct-12
Document File: 2 page(s) / 55K

Publishing Venue

Motorola

Related People

Francine Y. Robb: AUTHOR

Abstract

It has been found that the addition of oxygen to a chlorine plasma affects the etch rate ratios of polysilicon-to-titanium silicide-to-silicon dioxide as shown in the attached figure. High etch rate ratios are required in applications where it is necessary to etch polysilicon down to thin gate oxide, or where polysillcon must be etched while titanium silicide is exposed. The mechanism for the etch rate differences of the various materials is thought to be related to their varying oxidation affinities. Thus the etch rate of an easily oxidized material, such as a titanium containing compound, would be lower due to "oxide" formation than a less easily oxidized material such as silicon.

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MOTOROLA Technical Developments Volume 4 April 1984

THE CONTROL OF PLASMA ETCH SELECTIVITIES VIA OXYGEN ADDITION TO CHLORINE- BASED PLASMAS

by Francine Y. Robb

   It has been found that the addition of oxygen to a chlorine plasma affects the etch rate ratios of polysilicon-to-titanium silicide-to-silicon dioxide as shown in the attached figure. High etch rate ratios are required in applications where it is necessary to etch polysilicon down to thin gate oxide, or where polysillcon must be etched while titanium silicide is exposed. The mechanism for the etch rate differences of the various materials is thought to be related to their varying oxidation affinities. Thus the etch rate of an easily oxidized material, such as a titanium containing compound, would be lower due to "oxide" formation than a less easily oxidized material such as silicon.

'9 Motorola, Inc. 1984 28

[This page contains 15 pictures or other non-text objects]

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MOIOROLA Technical Developments Volume4 April 1984

S-I&L; WAFER PLASMA ETCHER

TOTAL FLOW = 100 SCCM

1 WATT PER CM 2 / 200 KHz

UNDOPED

m2-i

ETCH RATE

A/MINUTE

6000

6000 - -I \

4000 -

2000 -

-------------__

1 I I I I I 1
0.01 0.02 0.03 0.44 4.45 4.06 0.07

02 /Cl 2 FLOW RATE RATIO

C Motorola, Inc. 1984 29

[This page contains 17 pictures or other non-text objects]