Indirect endpoint detection by chemical reaction and chemiluminescence
AssigneeInternational Business Machines Corporation
InventorsLeping Li, James Albert Gilhooly, Clifford Owen Morgan, III, William Joseph Surovic, Cong Wei
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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.
Claims5
An apparatus for detecting the endpoint for removal of a target film overlying a stopping film by a chemical-mechanical polishing process using a polishing slurry, the apparatus comprising:
- an extractor for extracting a chemical reaction product as a gas from the slurry, the chemical reaction product being selectively generated in a chemical reaction with one of the stopping film and the target film and dissolved in the slurry during the process;
- a converter for converting the chemical reaction product to a separate product;
- means for producing excited molecules from the separate product;
- and
- a monitor for monitoring the level of light emitted from the excited molecules as the target film is removed.
Dependencies are inferred from the claim text.