Patent ID: 6222321
Filing Date: 2001-04-24
Classification: H01J,H05H

Abstract:
A circuit that causes at least two substantially constant currents to flow to at least two electrodes in a plasma chamber, comprising:a first power source that generates a substantially constant supply of a first direct current, said first power source having an output lead coupled to a first electrode, and a common return lead coupled to a circuit common;a second power source that generates a substantially constant supply of a second direct current, said second power source having an output lead coupled to a second electrode and a common return lead coupled to a circuit common;a first switch coupled between said first electrode and said circuit common that, when closed, causes current to flow from said second power source through said plasma chamber from said second electrode to said first electrode and shunts current from said first power source to said circuit common;a second switch coupled between said second electrode and said circuit common that, when closed, causes current to flow from said first power source in a second direction through said plasma chamber from said first electrode to said second electrode, and shunts current from said second power source to said circuit common.