Plasma etching of copper films at low temperature

摘要

Experimental verification of a low temperature ( < 20℃), reactive plasma etch process for copper films is presented. The plasma etch process, proposed previously from a thermochemical analysis of the Cu-Cl-H system, is executed in two steps. In the first step, copper films are exposed to a Cl_2 plasma to preferentially form CuCl_2, which is volatilized as Cu_3Cl_3 by exposure to a H_2 plasma in the second step. Plasma etching of thin films (9 nm) and thicker films (400 nm) of copper has been performed; chemical composition of sample surfaces before and after etching has been determined by X-ray photoelectron and flame atomic absorption spectroscopies.