Effect of target grain size on target sputter etching morphology and performance

Abstract

In this paper, three large scalar high-purity solid copper targets with different grain sizes are sputtered under the same experimental conditions. The sputter etching mechanism of grains on the target surface and the influence of target grain size on the sputter etching morphology were observed. Moreover, the target voltage of the three targets has also been measured. The results reveal that the sputtering of the grain on the target surface is extending from the grain boundary to the grain interior. Targets with different grain sizes show different target voltages depending on the sputter etching morphology. The target with a small grain size has a uniform and dense morphology with connected pits and bulges and a slight “black slump.” This morphology renders a higher target voltage than ones with larger grain sizes, which is due to the recapture of secondary electrons on the surface of the target.