Indirect endpoint detection by chemical reaction and chemiluminescence

Abstract

Detection of the endpoint for removal of a target film overlying a stopping film by removing the target film with a process that selectively generates a chemical reaction product (for example ammonia when polishing a wafer with a nitride film in a slurry containing KOH) with one of the stopping film and the target film, converting the chemical reaction product to a separate product, producing excited molecules from the separate product, and monitoring the level of light emitted from the excited molecules as the target film is removed.

Dependencies are inferred from the claim text.