Patent ID: 9711375
Date: 2017-07-18
CPC Classifications: H01J,H01L

Claim:
1. A plasma processing apparatus comprising: a processing chamber disposed within a vacuum vessel and depressurized inside to generate plasma therein; a wafer stage disposed in the processing chamber to mount a wafer to be processed thereon; a first power supply which is configured to supply first power of an electric field provided from over the vacuum vessel into the processing chamber to generate the plasma, the electric field being supplied in a first frequency with repetition of a high output and a low output during processing of the wafer; a second power supply which is configured to supply second power of a second frequency to an electrode disposed within the wafer stage; a first matching unit which is disposed on a feeding path of the first power from the first power supply to the vacuum vessel and which is configured to adjust impedance between the first power supply and the plasma in the processing chamber; and a second matching unit which is disposed on a feeding path of the second power from the second power supply to the electrode of the wafer stage and which is configured to adjust an impedance between the second power supply and the plasma in the processing chamber, wherein the first power supply is configured to be capable of changing the first power of the electric field, in the processing of the wafer, in values of the high output, the low output, and a ratio between a time period over which the first power is in the high output and a time period over which the first power is in the low output, respectively; and wherein the first matching unit includes two adjustable capacitances; and a control device is configured to control the first power supply and the first matching unit to adjust the impedance between the first power supply and the plasma to a first value for first power by the two adjustable capacitances during the processing of the wafer, the first value of the impedance being determined between a load impedance at a time of the high output and at a time of the low output of the first power.