Patent ID: 7432468

Claim:
A plasma processing apparatus comprising: a plurality of waveguides each having a plurality of slots; a dielectric member through which microwaves propagated via the plurality of waveguides and via the plurality of slots are transmitted; and a processing chamber in which a gas is raised to plasma by the microwaves transmitted through the dielectric member and a subject to be processed is processed with the plasma, wherein: the dielectric member is constituted with a plurality of dielectric parts that are supported by a beam, each of the plurality of dielectric parts transmitting the microwaves propagated through one or more of the plurality of waveguides and passed thereto via one or more slots in each of the waveguides; and wherein the beam projects from the bottom surface of the dielectric parts toward the subject to be processed to the extent that an electron density Ne of the plasma in the vicinity of an edge of the projected beam becomes equal to or greater than a cutoff electron density Nc of the plasma, wherein an upper limit value hc of a projected position of beam is calculated as: hc=2 1/2 ×a×(1nNo−1nNc)/ 2 π, with “No” representing the plasma electron density near the dielectric parts and “a” representing the smallest value of the interval between adjacent beams.