Reactive Ion Etching of Thin Gold Films

Abstract

Reactive ion etching of thin gold films using chlorine , carbon tetrafluoride , carbon tetrachloride , and a mixture of these gases was investigated. Etch rates were studied by changing the etching gas composition, pressure, and power in a parallel‐plate reactive ion etcher. Reactive ion etching of gold using or yields a low etch rate and a carbon residue formation on etched surfaces. The introduction of to the did not improve the etch rate. However, the addition of to was found to etch the carbon residue and significantly enhance the etch rate of gold. The etch rate of gold varies from 30 Å/min using a chlorine plasma to 990 Å/min using a mixture of and . For a mixture of and , the etch rate of gold was found to be twice the etch rate of positive photoresist, suggesting that positive photoresist is a practical mask for most applications involving the reactive ion etching of thin gold films.