Etching characteristics of Au thin films using inductively coupled Cl-2/Ar plasma

Abstract

In this study, An thin films were etched with a Cl-2/Ar gas combination using inductively coupled plasma. The etch properties were measured for different gas mixing ratios of Cl-2/(Cl-2+Ar) while the other process conditions were fixed at a rf power of 700 W, a dc bias voltage of -150 V, a chamber pressure of 15 mTorr and a substrate temperature of 30 degreesC. The highest etch rate of the An thin film was 3500 Angstrom/min and the selectivity of An to SiO2 was 4.4 at a Cl-2/(Cl-2+Ar) gas mixing ratio of 0.2. The surface reaction of the etched An thin films was investigated using x-ray photoelectron spectroscopy (XPS) analysis. There is a chemical reaction between Cl and An. Au-Cl is hard to remove from the surface because of its high melting point. The etching products can be sputtered by Ar ion bombardment. We obtained the clean and steep profile.