Profile control is required when etching silicon for trench isolation or capacitor applications. Trench profile control is often obtained by using etch chemistries and conditions that result in deposition of passivation material on the newly exposed sidewalls of the trenches during etch. The sidewall passivation material must then be removed before further processing of the trench structures. An effective trench clean is critical to the quality of the interface between the monocrystalline silicon sidewall of the trench and subsequently grown / deposited layers. Current practice for trench clean often involves dilute BF wet etch. Inherent in this approach is the assumption that the sidewall passivation material is SiOx with x-2. The composition, thickness and etch rate of the sidewall passivation material are important variables to consider for development and optimization of any trench clean process. In this work, several analytical techniques (SEM, Auger, TEM) were applied to characterize the sidewall passivation material produced in a magnetically-enhanced single wafer trench etch tool. The results suggest that variation of etch conditions can affect not only the shape and thickness but also the composition of the passivation material deposited during trench etch.

Date Published: 30 January 1990
PDF: 16 pages
Proc. SPIE 1185, Dry Processing for Submicrometer Lithography, (30 January 1990); doi: 10.1117/12.978056

Published in SPIE Proceedings Vol. 1185:
Dry Processing for Submicrometer Lithography
James A. Bondur; Alan R. Reinberg, Editor(s)