Surface Chemical Reaction Model of Silicon Dioxide Film Etching by Dilute Hydrogen Fluoride Using a Single Wafer Wet Etcher

摘要

A surface chemical reaction model of silicon dioxide film etching by hydrogen fluoride aqueous solution using a single wafer wet etcher was numerically evaluated taking into account the Langmuir-type rate theory and the transport phenomena. The surface reaction process was assumed to consist of three steps, such as (i) hydrogen fluoride adsorption at the silicon dioxide surface, (ii) chemical reaction of silicon dioxide with hydrogen fluoride and (Hi) desorption of the by-product from the surface. The rate constants determined by calculation which could reproduce the silicon dioxide etching rate obtained by experiment. The rate limiting step was additionally evaluated.