PARTICLE GENERATION IN ION IMPLANTERS

Optical elements at potential represent a serious concern for particle generation in ion implanters. Conditioning of acceleration columns is a well known phenomenon in accelerators but less well known is the fa ct that the microdischarging, which accompanies the conditioning proce ss, results in high particle production. Ad elements at voltage will e xhibit microdischarging, but careful design can greatly reduce it and control the associated particle generation. Moreover, microdischarging can be detected, so that the implanter control system can detect and interlock recipes against microdischarge generated particulate contami nation.