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Proceedings Paper

New method for end-point detection in reactive ion etching of polysilicon
Author(s): Shahid Aslam; Naresh C. Das; Peter K. Shu
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Paper Abstract

Reactive ion etching (RIE) is commonly used, as a process tool, for the etching of polysilicon, silicon dioxide, silicon nitride and other thin film deposits. One of the key requirements of the etching process is the accurate end-point detection of the process. There exist a number of process monitoring techniques for end-point detection, these however are costly to install and maintain. In response to this requirement, a new method for end-point detection of polysilicon topography etching in single wafer plasma reactive ion etcher is presented here, which incurs no added costs. The method is based upon experimental results correlating polysilicon etching end-point with the increase in the cathodic self-bias voltage developed across the substrate. It is shown that the end-point of polysilicon topography etching can be found by monitoring the first derivative of the self- bias voltage with time. Using this method it has been demonstrated that accurate end-point detection of polysilicon etching can be obtained with a residue free field, near- vertical polysilicon profile and critical dimension loss of less than 0.05 micrometer.

Paper Details

Date Published: 25 August 1997
PDF: 6 pages
Proc. SPIE 3213, Process, Equipment, and Materials Control in Integrated Circuit Manufacturing III, (25 August 1997); doi: 10.1117/12.284623
Show Author Affiliations
Shahid Aslam, Hughes STX (United States)
Naresh C. Das, Hughes STX (United States)
Peter K. Shu, NASA Goddard Space Flight Ctr. (United States)

Published in SPIE Proceedings Vol. 3213:
Process, Equipment, and Materials Control in Integrated Circuit Manufacturing III
Abe Ghanbari; Anthony J. Toprac, Editor(s)

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