Improvement of sample-cooling in electron cyclotron resonance plasma etching machine

摘要

For reliable and reproducible fabrication process of low T_C superconducting integrated circuits, we have improved a colling efficiency between a 3-in. -diam wafer and a substrate holder in an electron cyclotron resonance (ECR) plasma etching machine. We have obtained a high cooling efficiency by improving a substrate holder structure and adjusting flow rate of cooling He gas. Under the sufficient cooling of the wafer, we investigated variation in etching rate across the wafer and etching selectivities.