Optical Emission Spectroscopy was implemented for determining the endpoint of film removal through detecting shifts in plasma emission intensity during an etch process. A preliminary procedure has been developed for detecting endpoint with the factory nitride and oxide etch processes at RIT. In conjunction with the development of an endpoint process, the minimum sensitivity for the OES endpoint system was investigated. A minimum of 0.5% exposed nitride versus resist area is required for accurately detecting endpoint on Nitride, while 5% open area is necessary for Oxide.
Miller, Keith R.
"Optical Emission Spectroscopy for Plasma Etch Endpoint Detection,"
Journal of the Microelectronic Engineering Conference: Vol. 11
, Article 5.
Available at: http://scholarworks.rit.edu/ritamec/vol11/iss1/5