Plasma processing

Patent Granted A microwave plasma processing apparatus 100 allows microwaves, passed through a plurality of slots 37, to be transmitted through a plurality of dielectric parts 31 supported by beams 26, raises a gas to plasma with the transmitted microwaves and processes a substrate G with the plasma. The beams 26 are made to project out toward the substrate so as to ensure that the plasma electron density Ne around the ends of the beams 26 is equal to or greater than a cutoff plasma electron density Nc.