US Patent 7102132 Process monitoring using infrared optical diagnostics

A method and apparatus for real-time monitoring of the substrate and the gaseous process environment in a semi-conductor process step is described. The method uses infrared spectroscopy for in-situ analysis of gaseous molecular species in the process region and characterization of adsorbed chemical species on a substrate. The process monitoring can be applied to endpoint- and fault detection in etching and deposition processes, in addition to chamber cleaning and chamber condition steps.