Selective Formation of a SnO2 Cap Layer, Its Growth Behavior, and Oxidation Resistance

Abstract

In this paper, we propose a new method of cap-layer formation. The cap layer of SnO2 is formed by the displacement plating of Sn, followed by the oxidation of the plated Sn. An excellent plating selectivity was found between Cu and SiO2, but not with SiOCH. The SnO2 layer of 90 nm thickness showed a good oxidation resistance of the underlying Cu after heat treatment at 480 °C in air (PO2=105 Pa). In contrast, the SnO2 layers of 6 and 9 nm thickness showed oxidation resistance at 400 °C in Ar+10 ppm O2 (PO2=1 Pa), but not in Ar+1000 ppm O2 (PO2=100 Pa).