Apparatus and method for reducing particle contamination in an etcher

摘要

An apparatus and a method for reducing particle contamination by a polymeric film in a plasma etcher are described. In the apparatus for dry etching a wafer, a wafer holder and a ring member positioned juxtaposed to the holder are provided wherein the ring member is used to confine a plasma cloud generated in the chamber cavity onto an exposed surface of the wafer. The ring member has surface areas that is substantially exposed to the chamber interior, the surface areas are roughened to a depth between about 1 mum and about 10 mum between peaks and valleys formed in the roughened surfaces by either a sand-blasting method or by a chemical etching method. When the sand-blasting method is utilized to roughen the surface of the ring member, i.e., a focus ring in a reactive ion etching apparatus, particles having a mesh size between 200 mesh and 80 mesh may be suitably used. The roughened surfaces on the focus ring improve adhesion between a polymeric film necessarily produced during the plasma etching process for sidewall passivation and the surface of the quartz focus ring such that polymer film does not flake-off to form contaminants for the wafer positioned in the etch chamber.