REACTIVE ION ETCHING IN THE GASEOUS ELECTRONICS CONFERENCE RF REFERENCE CELL

This paper describes the results of using the GEC reference cell as a reactive ion etcher. Silicon wafers with layers of polysilicon and sil icon dioxide on crystaline silicon patterned with photoresist have bee n investigated with fluorine and chlorine chemistries. Scanning electr on microscopy (SEM), profilometry, and refraction techniques were used to determine the etch parameters such as etch rate, uniformity and se lectivity. The discharges are in general monitored by measuring the op tical emission spectroscopy and the bias voltages. For fluorine chemis tries, etch rates ranged from 5 nm/min to 177 nm/min, and for chlorine chemistries, etch rates ranged from 25 nm/min to 90 nm/min. Depending upon the discharge and chemistry conditions, similar etch rates and e tch patterns of different GEC cells were obtained. Etch rates and rela tive fluorine concentrations obtained from a commercial etcher were co mpared to the GEC reference cell and were found to be similar although the GEC cell generally gave lower etch rates than the commercial etch er.