Patent ID: 6433553
Filing Date: 2002-08-13
Classification: G01R,H01J

Abstract:
A method of measuring an ion current in a plasma processing system for implanting ions into a target in a plasma processing chamber, said plasma processing system including first and second electrodes, wherein a voltage pulse is applied across the first and second electrodes, the method comprising:(a) electrically coupling a capacitor between the first and second electrodes to receive the voltage pulse and selecting the capacitor to have a same or nearly the same capacitance as a first capacitance between the first and second electrodes; (b) measuring a first current supplied to the first and second electrodes during the voltage pulse and providing a first current signal representative of the first current; (c) measuring a second current supplied to the capacitor during the voltage pulse and providing a second current signal representative of the second current; and (d) subtracting the second current signal from the first current signal to provide an ion current signal representative of the ion current.