The invention provides an arc
coating apparatus having a steering
magnetic field source comprising steering conductors disposed along the short sides of a rectangular target behind the target, and a magnetic focusing
system disposed along the long sides of the target in front of the target which confines the flow of
plasma between magnetic fields generated on opposite long sides of the target. The
plasma focusing
system can be used to deflect the
plasma flow off of the working axis of the
cathode. Each steering conductor can be controlled independently. In a further embodiment, electrically independent steering conductors are disposed along opposite long sides of the
cathode plate, and by selectively varying a current through one conductor, the path of the arc spot shifts to widen an
erosion corridor. The invention also provides a plurality of internal anodes, and optionally a surrounding
anode for deflecting the
plasma flow and preserving a high
ionization level of the plasma. The invention also provides a shield at
floating potential, restricting the
cathode spot from migrating into selected regions of the target
evaporation surface outside of the desired
erosion zone. The shield may be positioned immediately above the region of the
target surface in the vicinity of the
anode, protecting the
anode from deposition of cathodic evaporate and providing better distribution of cathodic evaporate over the substrates to be coated. The invention further provides correcting magnets adjacent to the short sides of the target, to move the arc spot between the long sides.