Patent ID: 8283255

Claim:
A method for etching features in a silicon layer, comprising forming a hard mask layer over the silicon layer, wherein the hard mask layer is silicon-based, wherein the forming the hard mask layer comprises: forming a first layer over the silicon layer, wherein the first layer is Si 3 N 4 ; and forming a second layer over the first layer, wherein the second layer is SiO 2 ; forming a photoresist layer over the hard mask layer; opening the hard mask layer; and stripping the photoresist layer, comprising providing a stripping gas; forming a plasma with the stripping gas by providing a high frequency RF power with a frequency greater than or equal to 27 MHz and a low frequency RF power with a frequency less than 20 MHz, wherein the low frequency RF power has a power less than 50 watts; and stopping the stripping gas when the photoresist layer is stripped.