Dependence of ECR Plasma Etching Characteristics on Sub Magnetic Field and Substrate Position

Abstract

By using an ECR plasma etching system equipped with a sub magnetic coil, the dependences of etching characteristics on sub magnetic field and substrate position of polyimide film etching are investigated. A bowing-free etching profile, etching rate of more than 1 µm/min, and etching rate uniformity of ±5% on a 6 inches diameter substrate are achieved at the ECR position under O₂/SF₆ etching gas pressure of 5×10^-4 Torr. Etching characteristics at the ECR position are explained by collimated ions, extremely high ion current density and uniform ion current compared with the off-ECR position.