Plasma Quest ECR Etcher, pquest (contaminated)
Plasma Quest (pquest) is an ECR plasma etcher primarily used for etching GaAs. It only accepts 4-inch wafers.
To aid in process performance, chemistries are segregated on a biweekly schedule, where "chlorine" runs for 10 days and "fluorine" runs for 4 days. On "chlorine" days, fluorine chemistries and chuck temperature above 50 C are prohibited. On "fluorine" days, all standard chemistries, including chlorine, and chuck temperatures above 50 C are allowed. The clock restarts with "chlorine" immediately following a chamber clean (scheduled for alternative Fridays.)