METHOD FOR ACHIEVING ULTRA-HIGH SELECTIVITY WHILE ETCHING SILICON NITRIDE

摘要

Provided are methods for selectively etching silicon nitride on a semiconductor substrate by providing silicon to a plasma to achieve high etch selectivity of silicon nitride to silicon-containing materials. The methods include a step of providing silicon from a solid or fluidic silicon source or both. The solid silicon source may be in upstream of a substrate or in a remote plasma generator, such as at or near a showerhead of a process chamber. A silicon gas source may flow to the plasma during etching.