A Water-Amine-Complexing Agent System for Etching Silicon

Abstract

Ternary mixtures of water, amine, and complexing agent have been found to etch silicon. The silicon etch rate has been investigated as a function of variations in both solution and material parameters. A parallel investigation has been concerned with the etching characteristics of silicon samples coated with silicon dioxide films. Applications of this etching system to semicon-ductor device t chnology has provided a tool for the chemical shaping of sili-con as well as the evaluation of protective surface films on silicon substrates. It has been found that ternary mixtures of water, amines, and complexing agents dissolve silicon, with water being a necessary and active component of the etch. Significant among the properties of these etches are the large number of parameters on which the etch rate depends and the extremely low rate of attack on silica. It has been possible to etch silicon into