Etch characteristics of Cr by using Cl-2/O-2 gas mixtures with electron cyclotron resonance plasma

We investigated the etch characteristics of chromium films by using Cl-2/O- 2 gas mixtures with electron cyclotron resonance plasma. In order to examin e the chemical etch characteristics of Cl-2/O-2 gas plasma, we examined the etch rate with various gas mixing ratios. By X-ray photoelectron spectrosc opy (XPS), the surface reaction on the chromium films during the etch was e xamined. At the same time, the plasma characteristics were examined by opti cal emission spectroscopy. From XPS analyses, it was confirmed that a chrom ium oxychloride (CrClxOy) layer was formed on the surface by the etch using Cl-2/O-2 gas mixtures. We observed a new characteristic emission line at 5 17 nm during the etch of chromium films with Cl-2/O-2 gas mixtures, using o ptical emission spectroscopy. It was found that the peak intensity of this emission line had a similar behavior to the etch rate. It was proposed that the emission line of 517 nm should result from chromium compounds with the oxidation state of Cr3+. (C) 2001 The Electrochemical Society.