Smoothing of Diamond-Turned Copper Surfaces Using Ion Beams with Aid of Planarizing Film

We investigate ion beam etching that uses a planarizing film for smoothing copper surfaces with nm-order roughness. Copper surfaces were cut using a turning machine with a single-crystal diamond tool to prepare mirror surfaces as workpieces. Then, the surfaces were coated with photoresist, and etched using ion beams with an appropriate incidence angle. As a result, tool marks exhibited on the turned surfaces were removed, and the surfaces with a smoothness of nm order were further improved by the ion beam process.