US Patent 8083891 Plasma processing apparatus and the upper electrode unit

In a plasma processing apparatus that executes plasma processing on a semiconductor wafer placed inside a processing chamber by generating plasma with a processing gas supplied through a gas supply hole at an upper electrode (shower head) disposed inside the processing chamber, an interchangeable insert member is inserted at a gas passing hole at a gas supply unit to prevent entry of charged particles in the plasma generated in the processing chamber into the gas supply unit. This structure makes it possible to fully prevent the entry of charged particles in the plasma generated inside the processing chamber into the gas supply unit.