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Proceedings Paper

High-pressure CVD tungsten-stud formation using RIE cluster processes
Author(s): Hung Y. Ng; D. J. Dichauzi
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Paper Abstract

The use of CVD tungsten for filling of contacts and vias has been reported in many multilevel interconnection technology applications. W-stud formation is done by blanket tungsten deposition and subsequent either etchback or chemical-mechanical polishing (CMP). This paper presents the integration of both tungsten deposition and etchback processes in a commercial cluster tool, as compared to W-stud formation by CMP. Tungsten films were deposited at a high pressure of 70 Torr to fill high aspect ratio (3.5) contact holes without voids. Tensile stress of 10E9 dynes/cm2 measured for these films was higher by almost a factor of 2 than the low pressure tungsten films deposited at 0.85 Torr. A composite W film, deposited by both high and low pressure regime, has been utilized to have both advantages of via-filled characteristic and low film stress. A multistep RIE process had been used with the majority of W removed using a SF6/Cl2 plasma and the remaining W was then removed with Cl2/O2 to minimize the microloading phenomenon. The maximum W- plug recess, observed at the edge of the wafers, is only 0.1 micrometers . Electrical test results of W contact studs formed by clustered processes are compared to W-stud formation by CMP.

Paper Details

Date Published: 16 April 1993
PDF: 12 pages
Proc. SPIE 1803, Advanced Techniques for Integrated Circuit Processing II, (16 April 1993); doi: 10.1117/12.142929
Show Author Affiliations
Hung Y. Ng, IBM Thomas J. Watson Research Ctr. (United States)
D. J. Dichauzi, Genus, Inc. (United States)

Published in SPIE Proceedings Vol. 1803:
Advanced Techniques for Integrated Circuit Processing II
James A. Bondur; Gary Castleman; Lloyd R. Harriott; Terry R. Turner, Editor(s)

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