Electromagnetic wave supply mechanism and plasma processing apparatus

A plasma processing apparatus, comprising:

• a processing container;
• an electromagnetic wave supply mechanism configured to supply an electromagnetic wave into the processing container serving as a load;
• and
• a radio-frequency power source configured to generate the electromagnetic wave,
• wherein the electromagnetic wave supply mechanism includes a first branch circuit provided downstream of the radio-frequency power source and configured as a waveguide, the first branch circuit including a first waveguide having an input end, a plurality of second waveguides having respective output ends, and a branch point at which the first waveguide is branched into the plurality of second waveguides corresponding to n branches (where n is an integer equal to or greater than 2),
• wherein each of the output ends is connected to the load or an input end of a second branch circuit subsequent to the first branch circuit, and
• wherein, in the first branch circuit, when a total number of the output ends seen from the branch point is n, lengths of the second waveguides from the branch point to the n output ends differ from each other by m×λ/2+(λ/2)/n (where m is 0 or a positive integer).