| abstract |
A method for selectively etching a substrate is described. The method includes preparing a substrate comprising a silicon nitride layer overlying a silicon-containing contact region, and patterning the silicon nitride layer to expose the silicon-containing contact region using a plasma etching process in a plasma etching system. The plasma etching process uses a process composition having as incipient ingredients a process gas containing C, H and F, and a non-oxygen-containing additive gas, wherein the non-oxygen-containing additive gas includes H, or C, or both H and C, and excludes a halogen atom. |