SELECTIVE ETCH PROCESS FOR SILICON NITRIDE

摘要

A method for selectively etching a substrate (25, 140, 150, 300, 310, 510) is described. The method includes preparing a substrate (25, 140, 150, 300, 310, 510) comprising a silicon nitride layer (180, 320) overlying a silicon-containing contact region (172, 343), and patterning the silicon nitride layer (180, 320) to expose the silicon-containing contact region (172, 343) using a plasma etching process in a plasma etching system (1, 1 a, 1 b, 1 c, 1 c', 1 d, 1 e, 1f). 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.