Enhancement of Reactivity in Au Etching by Pulse-Time-Modulated Cl2 Plasma

In Al, Au and Pt metal etching processes, low etching rate and low etching selectivity are serious problems. To achieve a breakthrough in these problems, metal etching by pulse-time-modulated plasma was investigated. In particular, the Au etching rate was increased significantly in the pulsed plasma even when the ion energy decreases. However, an increase in the etching rate cannot be observed in Al etching. As a result, it is speculated that the increase in the Au etching rate is caused by the increase in the evaporation rate of Au etching products, which results from the injection of negative ions.