Feature evolution during plasma etching. II. Polycrystalline silicon etching

The effect of source power, bias power, chamber pressure, how rate, and fee d gas composition on profile evolution during polycrystalline silicon etchi ng with an oxide hardmask has been studied in a transformer-coupled plasma system. The large resultant data set provides a comprehensive look at featu re evolution as plasma parameters are varied. This data set is valuable for evaluating the importance of several proposed mechanisms for feature evolu tion and for validating computational models. Microtrench formation was fou nd to be a strong function of the plasma condition. A correlation between s idewall shape and microtrench development was observed. Profile development was found to be highly sensitive to feed gas composition. Results are cons istent with a previous study on the etching of crystalline silicon under id entical plasma conditions. (C) 2000 American Vacuum Society. [S0734-2101(00 )00901-5].