Feature evolution during plasma etching. II. Polycrystalline silicon etching

The effect of source power, bias power, chamber pressure, flow rate, and feed gas composition on profile evolution during polycrystalline silicon etching with an oxide hardmask has been studied in a transformer-coupled plasma system. The large resultant data set provides a comprehensive look at feature evolution as plasma parameters are varied. This data set is valuable for evaluating the importance of several proposed mechanisms for feature evolution and for validating computational models. Microtrench formation was found to be a strong function of the plasma condition. A correlation between sidewall shape and microtrench development was observed. Profile development was found to be highly sensitive to feed gas composition. Results are consistent with a previous study on the etching of crystalline silicon under identical plasma conditions.

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