Surface science issues in plasma etching

Abstract

Pattern transfer by plasma-based etching is one of several key processes required for fabricating silicon-based integrated circuits. We present a brief review of elementary plasma-etching processes on surfaces and within integrated-circuit microstructures—and an overview of recent work in our laboratory on plasma-etching aspects of the formation of self-aligned contacts to a polysilicon layer through a SiO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> layer and a Si <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> N <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</inf> etch-stop layer. The work illustrates the richness of associated surface science issues that must be understood and controlled in order to most effectively achieve plasma-based pattern transfer.