Filter circuit and plasma processing apparatus

A plasma processing apparatus, comprising:

• a processing container;
• and
• a filter circuit provided in a first power feed line for feeding power to an electrode exposed to an electromagnetic wave for generating plasma within the processing container,
• wherein the filter circuit includes:
• a housing made of a conductor and including an input port and an output port, each of the input port and the output port formed with an outer conductor and an inner conductor, wherein the housing is at ground potential together with the outer conductor of the input port and the outer conductor of the output port and is configured such that an internal space, in a plane view, has an area that extends in a first direction and in a second direction orthogonal to the first direction;
• a partition portion made of a conductor and connected to the housing to partition the internal space;
• and
• a second power feed line provided within the housing and insulated from the housing,
• wherein the second power feed line includes:
• an input-side conductor, which is the inner conductor of the input port;
• an output-side conductor, which is the inner conductor of the output port;
• an antenna portion connected to the input-side conductor and the output-side conductor and extending into the internal space so as to be stacked with the partition portion;
• and
• an antenna base configured to connect the input-side conductor, the output-side conductor, and the antenna portion, and
• wherein the internal space has a dimension in the second direction from the antenna base and a dimension in the first direction from the antenna base larger than the dimension in the second direction from the antenna base.