A microwave plasma reactor with a plurality of emitters and absorbers and a method for plasma processing a workpiece using such a microwave plasma reactor

A microwave plasma reactor comprising:

• a plasma chamber with a base, a top, and a side wall extending from the base to the top;
• a workpiece holder disposed at the base and comprising a supporting surface for supporting a workpiece;
• a gas flow system for feeding process gas into the plasma chamber and/or removing gas from the plasma chamber;
• one or more microwave generators adapted to generate microwaves at a frequency f;
• a plurality of microwave emitters each comprising an amplifier, a phase shifter and an emitting element, wherein each of the plurality of microwave emitters is connected to at least one of the one or more microwave generators, and wherein the emitting elements of the plurality of microwave emitters are mounted at the plasma chamber, and form an emitter array;
• one or more microwave absorbers configured to absorb microwaves at the frequency f, wherein each of the one or more microwave absorbers comprises an absorbing element, wherein the absorbing elements of the one or more microwave absorbers are mounted at the plasma chamber, and form an absorber array;
• and,
• an emitter control unit configured to control an amplification of the amplifier and a phase shift of the phase shifter for each or most of the plurality of microwave emitters and to generate a desired distribution of microwave power from the emitter array to one or multiple desired locations within the plasma chamber.