Plasma processing apparatus

1. A plasma processing apparatus comprising:

a processing chamber where plasma processing is performed on a sample;

a radio frequency power supply that supplies radio frequency power to generate plasma;

a sample stage on which the sample is placed;

a gas supply unit that supplies a gas to the processing chamber; and

a gas supply plate arranged on an upper portion of the processing chamber, a plurality of gas holes that supply a gas into the processing chamber being provided in the gas supply plate,

wherein the gas supply unit includes

a first pipe that supplies a first gas as a gas for etching process to the processing chamber, the first pipe having a first air-driven valve arranged thereon and which is a normally closed type air-driven valve;

a second pipe that supplies a second gas as a gas for etching process to the processing chamber, the second pipe having a second air-driven valve arranged thereon and which is a normally closed type air-driven valve;

a third pipe through which a third gas as a gas for deposition process flows, the third pipe being coupled to the second pipe, and the third pipe having a third air-driven valve arranged thereon which is a normally closed type air-driven valve; and

a fourth air-driven valve arranged on the second pipe, the fourth air-driven valve being a normally open type air-driven valve configured to prevent the third gas from flowing in a direction toward a supply source of the second gas,

wherein the second pipe is coupled to an inlet side of the processing chamber such that the second gas is supplied to the processing chamber from a height between the gas supply plate and the sample stage, and

wherein the third pipe is coupled to the second pipe at a point disposed between the fourth air-driven valve and a coupling location of the second pipe to the inlet side of the processing chamber.

2. The plasma processing apparatus according to claim 1 , wherein the fourth air-driven valve is arranged on a position close to the processing chamber with respect to the second air-driven valve.

3. The plasma processing apparatus according to claim 1 , wherein the control device is further configured to control the first air-driven valve and the second air-driven valve such that the second air-driven valve is opened when the first air-driven valve is opened, and the second air-driven valve is closed when the first air-driven valve is closed.

4. The plasma processing apparatus according to claim 3 ,

wherein the control device is configured to supply the first gas to the processing chamber and to close the fourth air-driven valve when the third gas is supplied to the processing chamber, and

wherein the first gas is an inert gas.

5. The plasma processing apparatus according to claim 1 , further comprising a 3-position spring return center exhaust type 5-port solenoid valve that controls air that drives the second air-driven valve and the third air-driven valve.

6. The plasma processing apparatus according to claim 1 , further comprising an air circuit that controls air that drives the first air-driven valve and the fourth air-driven valve,

wherein the air circuit includes a logic circuit unit that configures a logic circuit that establishes open/close conditions for the first air-driven valve and the fourth air-driven valve.

7. The plasma processing apparatus according to claim 6 , wherein the first air-driven valve and the fourth air-driven valve are opened and closed via a pilot valve in response to air supplied from the logic circuit.

8. The plasma processing apparatus according to claim 4 ,

wherein the first pipe is coupled to the processing chamber such that the first gas is supplied to the processing chamber via the gas supply plate.

9. The plasma processing apparatus according to claim 8 , further comprising a magnetic field forming mechanism that forms a magnetic field inside the processing chamber,

wherein the radio frequency power is radio frequency power of a microwave.