Patent ID: 7547635

Claim:
A method of etching openings in a dielectric layer, comprising: supporting a semiconductor substrate on a substrate support in a plasma etch reactor, the substrate having a dielectric layer and a patterned photoresist layer and/or hardmask above the dielectric layer; supplying to the plasma etch reactor an etchant gas comprising (i) a fluorocarbon gas (C x F y H z , where x≧1, y≧1, and z≧0), (ii) silane-containing gas, (iii) an optional oxygen-containing gas, and (iv) an optional inert gas; wherein the flow rate ratio of silane-containing gas to fluorocarbon gas is less than or equal to 0.1; energizing the etchant gas into a plasma state, and etching openings in the dielectric layer with increased photoresist and/or hardmask to dielectric layer selectivity and decreased photoresist distortion or striation, wherein the dielectric layer comprises an inorganic low-k material or an organic low-k material.