Plasma processing apparatus

A plasma processing apparatus comprising:

• a processing chamber in which a sample is subjected to plasma-processing;
• a radio frequency power source that supplies radio frequency power for generating plasma;
• a sample stage on which the sample is placed;
• a first flat plate arranged above the sample stage and having a first plurality of through holes each disposed only in a peripheral area portion of the first flat plate so as to not overlap with the sample stage in a plan view;
• a second flat plate arranged between the first flat plate and the sample stage and facing the first flat plate and having a second plurality of through holes, wherein each of the second plurality of through holes is disposed only in a central area portion of the second flat plate that is inside of and does not overlap with the first plurality of through holes disposed at the peripheral area portion of the first flat plate in the plan view;
• and
• a gas supply port arranged on a side surface of the processing chamber between the first flat plate and the second flat plate to supply gas, wherein the first flat plate and the second flat plate are spaced apart from each other and from the sample stage, the first plurality of through holes of the first plate and the second plurality of through holes of the second plate that do not overlap at the peripheral area portion of the first flat plate or at the central area portion of the second flat plate in the plan view, and the gas supply port are arranged to control a gas flow of the supplied gas to cause an etching distribution of a flow of radicals across a surface of the sample to be uniform.