A plasma etching equipment is designed and constructed for experimentation, and this plasma method has been used sucessfully to etch micrometer geometries on films of $SiO_2$ and Si. The effects of the power, the pressure and the gas composition on the etching are studied, and the results are summarized graphically. Etch rate for PR(AZ 1350J), $SiO_2$ and Si in a plasma of $O_2$ and $CF_4$ are measured. $CF_4$ plasma used for Si etching are unacceptable for very fine pattern features because of isotropic image and carbon contamination. Selectivities for Si/PR, $SiO_2$/PR and Si/$SiO_2$ are 5, 0.5 and 12 at 0.5 torr and 200 W, respectively.
