スパッタリングプラズマ中の銅原子密度の位置分解発光分光による測定およびそのターゲット−基板間距離による変化

Abstract

The copper atomic density within the sputter plasma and its dependence on Target-Substrate (T-S) distance has been investigated using the optical emission spectroscopy (OES). It has been understood that the atomic density of copper can be evaluated from the intensity ratio of two emission lines at 510.6 nm and 324.8 nm both from Cu neutral. At high atomic density environment, the intensity ratio I510/I324 becomes larger because the 324.8 nm emission is absorbed by the environmental copper atoms at ground state. In this study, we changed the T-S distance within 3575 mm, and measured the optical emission from the side along the line fixed at 1 cm away from the target surface. At pressures larger than 5 Pa, the intensity ratio increased by increasing the T-S distance, which denoted the increase of atomic density between the target and the substrate holder. It should originate from the diffusion-like atomic transport in which the substrate holder worked as the absorbing boundary.