Disclosed herein is a method of pattern etching a layer of a silicon-containing dielectric material. The method employs a plasma source gas including CF.sub.4 to CHF.sub.3, where the volumetric ratio of CF.sub.4 to CHF.sub.3 is within the range of about 2:3 to about 3:1; more typically, about 1:1 to about 2:1. Etching is performed at a process chamber pressure within the range of about 4 mTorr to about 60 mTorr. The method provides a selectivity for etching a silicon-containing dielectric layer relative to photoresist of 1.5:1 or better. The method also provides an etch profile sidewall angle ranging from 88.degree. to 92.degree. between said etched silicon-containing dielectric layer and an underlying horizontal layer. in the semiconductor structure. The method provides a smooth sidewall when used in combination with certain photoresists which are sensitive to 193 nm radiation.