A RGA STUDY OF THE CROSS-CONTAMINATION OF DOPANT SPECIES AND LOW-LEVEL IMPURITIES AND THE USE OF THE RGA AS A PROCESS MONITOR IN A VARIAN-180XP

Residual gas analysis (RGA) has been used to characterize the process of a Varian 180XP. The cross-contamination from dopant species has been investigated along with low level impurities from other sources, specifically resist, pump backstreaming, and implanter parts. This effect is clearly observed using RGA to measure total and partial pressures. This study concentrates on selected ranges of energy, dose, and beam current. The study also investigates the correlation of particle events in the implanter with a RGA and an in situ particle counter. A recommendation on the use of one or both tools as process monitors is made.