Physical vapor deposition plasma reactor with arcing suppression

A physical vapor deposition plasma reactor, comprising:

• a vacuum chamber including a sidewall, a ceiling and a retractable wafer support pedestal near a floor of the chamber, and a vacuum pump coupled to the chamber, said pedestal having an internal electrode and a grounded base with a conductive annular flange extending from said base, said base and said flange being retractable with said pedestal;
• a metal sputter target at said ceiling and a D.C. source coupled to said sputter target and capable of exciting a target-sputtering plasma near said target;
• an RF plasma source power generator coupled to said wafer support pedestal and having a frequency suitable for exciting kinetic electrons;
• an RF plasma bias power generator coupled to said internal electrode and having a frequency suitable for accelerating ions from said wafer-sputtering plasma across a plasma sheath near said wafer support pedestal;
• a removable shield adjacent said sidewall and plural compressible conductive tabs dispersed at generally uniform intervals on said annular flange and in contact with a bottom edge of said shield whenever said retractable wafer support pedestal is in an unretracted position, each of said uniform intervals being less than a wavelength corresponding to the frequency of said RF plasma source power generator;
• and
• wherein each of said compressible conductive tabs comprises a hollow cylinder formed of a metal layer and has a cylindrical axis parallel to a workpiece support plane of said workpiece support pedestal.