Experimental modeling of the etch characteristics of polysilicon in CCl4/He/O2 plasmas

The objective is to obtain a comprehensive set of statistical models for a variety of process data which accurately represent the behavior of a specific piece of equipment under a wide range of etch conditions. In particular, this study focuses on the control of etch rate, uniformity, and selectivity of n⁺-doped polysilicon in a CCl₄/He/O₂ plasma generated by a Lam Research Autotech 490 single-wafer system operating at 13.56 MHz. These responses were monitored under the variation of six input parameters: RF power, pressure, electrode spacing, and the three gas flows. These parameters are fitted to quadratic response surface models. Although the models obtained are generated for a specific process running on a specific piece of equipment, the methodology outlined is general enough to be applied to many semiconductor manufacturing processes