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Proceedings Paper

High-density plasma etching of aluminum copper on titanium tungsten
Author(s): Kim Dang
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Paper Abstract

A multi-step high density plasma etch process, based on chlorine and sulfur hexafluoride chemistry (SF6), for LRC single wafer metal etcher was developed, characterized and optimized to anisotropically etch the metal stack which consists of a thin titanium tungsten ARC, hot deposited aluminum copper over titanium tungsten. The titanium tungsten used in the metal structure presents unique constraints on etch selectivity to underlying film while simultaneously requiring clearing metal stringers. The etching was further complicated by lateral etching of aluminum copper (AlCu) during titanium tungsten (TiW) etch and overetch steps. With the help of design-of-experiment techniques, multi-variable factorial experiments were conducted to determine the optimum processes for the bulk metal etch, barrier metal layer etch and overetch steps. Characterization parameters include the metal etch rate, etch selectivity, CD line-width, metal resistance and plasma charging damages. Special attention was paid to the overetch window since the metal quality is very sensitive to the overetch conditions. Insufficient overetch may leave metal stingers or metal shorts. Excessive overetch may cause severe CD undercutting and great loss of TEOS oxide under-layer.

Paper Details

Date Published: 3 September 1999
PDF: 12 pages
Proc. SPIE 3882, Process, Equipment, and Materials Control in Integrated Circuit Manufacturing V, (3 September 1999); doi: 10.1117/12.361318
Show Author Affiliations
Kim Dang, Motorola, Inc. (United States)

Published in SPIE Proceedings Vol. 3882:
Process, Equipment, and Materials Control in Integrated Circuit Manufacturing V
Anthony J. Toprac; Kim Dang, Editor(s)

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