Silicon nitride has been extensively used as a hard mask for the local oxidation of silicon (LOCOS) for the processing of CMOS devices. Plasma etching is an ideal etch process for patterning the silicon nitride. An optimized etch process was developed for silicon nitride using the LAM-490 plasma etcher. A designed experiment was created, executed, and analyzed. The parameters investigated were SF6 flow, He flow, pressure, power, and electrode gap. The responses examined were silicon nitride uniformity, silicon nitride etch rate, silicon nitride to oxide selectivity and silicon nitride to photoresist selectivity. Through analysis of the experimental results optimal factor settings were determined. A recipe was created on the LAM-490 with the optimal factor settings and endpoint detection was incorporated into the optimal recipe.
"Development of Silicon Nitride Etch Process,"
Journal of the Microelectronic Engineering Conference: Vol. 12
, Article 8.
Available at: http://scholarworks.rit.edu/ritamec/vol12/iss1/8