Plasma Cleaning and Etching Using Quartz Bell Jar with SnO2 Transparent Thin-Film Heater in CHF3–SiO2 Mocrowave Etching System

Abstract

A thermally controllable quartz bell jar with a SnO2 transparent thin-film heater was developed. The heating effect of the quartz bell jar on plasma cleaning and etching was investigated in a CHF3–SiO2 microwave etching system. By means of quartz bell jar heating, plasma polymer deposition on the inside wall of the quartz bell jar was decreased, the plasma-cleaning time was shortened and the SiO2/poly-Si selectivity was increased. In the reaction chamber, etching and plasma polymerization take place on the reaction chamber wall as well as on the wafer. The concentration distribution of radicals and ions in the plasma is dependent on these reactions. Accordingly, control of the reaction chamber wall temperature is important both to improve the etching characteristics and to prevent time fluctuation of the etching characteristics.