Apparatus for controlling matching network of a vacuum plasma processor and memory for same

摘要

A load including a plasma discharge in a vacuum plasma processing chamber is matched to an r.f. source that supplies sufficient power to the discharge to maintain the discharge. A matching network connected between the source and a plasma excitation component of the chamber includes first and second variable reactances. A microprocessor causes the value of the first reactance to be varied while the value of the other reactance stays constant until power reflected from the load to output terminals of the source is minimized. The microprocessor causes the value of the second reactance to then be varied while the value of the first reactance stays constant until reflected power is minimized. The reactance values are alternately changed until the reflected minimum power does not change, at which time there is a match. To initiate the discharge, the microprocessor causes the value of the one reactance to change while the value of the other reactance stays constant.