Patent ID: 9161428
Filing Date: 2015-10-13
Classification: H01J,H05H

Abstract:
1. A plasma reactor for processing a workpiece, comprising: a vacuum chamber comprising a ceiling and a side wall, a workpiece support pedestal in said chamber having a workpiece support surface, and plural coil antennas; plural impedance matches and plural RF power amplifiers coupled to respective ones of said plural coil antennas through respective ones of said plural impedance matches, one of said plural RF amplifiers being a reference RF amplifier; a clock signal source coupled to said reference RF power amplifier, and respective phase shifters coupled between said clock signal source and at least respective ones of the RF power amplifiers other than said reference RF amplifier, each of said phase shifter having a phase shifter control input; plural RF sensor probes, respective ones of the plural RF sensor probes coupled or adjacent to respective ones of said plural RF coil antennas, one of said RF sensor probes being a reference RF sensor probe; respective phase detectors each having a phase detector output and a respective pair of phase detector inputs, one phase detector input in each of said respective pair of phase detector inputs being coupled to a respective one of said plural RF sensor probes other than the reference RF sensor probe, the other phase detector input in each of said respective pair of phase detector inputs being coupled to said reference RF sensor probe; a user interface having a plurality of user interface outputs defining a user-selected phase difference between said reference RF sensor probe and a respective one of the remaining RF sensor probes; and a feedback controller stage coupled to (a) respective ones of said phase detector outputs and (b) respective ones of said user interface outputs, said feedback controller stage further comprising respective controller outputs coupled to respective ones of said phase shifter control inputs.