Chemical and Biomolecular Engineering, Department of


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CleiLents, L.D., Busse, J. E., and Mehta, J., "Reaction Mechanisms and Rate Limitations in Dry Etching of Silicon Dioxide with Anhydrous Hydrogen Fluoride," Semiconductor Fabrication; Technology and Metrology, ASTM STP 990, Dinesh C. Gupta, editor, American Society for Testing and Materials, 1989.


Copyright 1989 by ASTM International. Used by permission.


A novel dry etching process for silicon dioxide has been developed. This process, carried out at ambient temperature and pressure, uses anhydrous hydrogen fluoride, water vapor in a nitrogen carrier, and a unique processing sequence to achieve etch rates of about 200A/second, with 5 percent or better uniformity.

The overall reaction is a complicated sequence of surface hydration and surface fluorlnation by adsorption, reaction, and product desorptlon. This paper presents two proposed reaction mechanisms and describes how experimental data from a laminar flow reactor were used to evaluate the mechanisms.