Veils-free DRY (ICP) etching of gold films with a vertical sharp sidewall

This paper presents a new method of dry etching for thin Au films in a dual frequency inductively coupled plasma (ICP) system on Si substrates to prevent veils of etched Au particles over the sidewall and to obtain vertical sharp sidewalls of patterned Au films. After optimizing ICP system process parameters, deposition of a thin Ti film on top of the Au film has been examined on the redeposition of etched Au particles over the sidewalls. The results show that depositing a thin Ti film on top of the Au film can prevent the redeposition of etched Au particles on the sidewall, and also a vertical sharp sidewall of the Au film can be obtained even if a thicker Au film with realization of this new method. Depending on the results of this work, we propose a new method that eliminates the redeposition of the etched Au particles on the sidewall for obtaining a vertical sharp sidewall of Au film with the dry Au etch process