Electron beam plasma source with profiled magnet shield for uniform plasma generation

A plasma reactor for processing a workpiece, comprising:

• a processing chamber comprising a chamber ceiling and a chamber side wall and an electron beam opening in said chamber side wall, a workpiece support pedestal in said processing chamber having a workpiece support surface facing said chamber ceiling and defining a workpiece processing region between said workpiece support surface and said chamber ceiling, said electron beam opening facing said workpiece processing region;
• an electron beam source chamber comprising a source enclosure, said source enclosure defining an electron beam propagation path along a longitudinal direction extending into said workpiece processing region;
• an electromagnet surrounding said source chamber, said source enclosure and said electron beam opening extending along a transverse direction that is non-parallel to said longitudinal direction;
• and
• a shield disposed between said source chamber and said electromagnet, said shield having an edge defining a shield length, said edge having a profile corresponding to a distribution of said shield length along said transverse direction.