Plasma processing apparatus and plasma processing method
A controller disclosed herein drives, in a first step, a high frequency generating source at a first energy condition, and drives, in a second step, a high frequency generating source at a second energy condition. Prior to a switching time of the first step and the second step, the controller switches gas species supplied from the gas supply system into the processing container, and sets a gas flow rate in an initial period just after the switching to be larger than a gas flow rate in a stabilization period after lapse of the initial period.
1. A plasma processing apparatus, comprising:
a processing container;
a gas supply system configured to supply a gas into the processing container;
a high frequency generating source configured to introduce high frequency waves for plasma generation into the processing container;
an automatic pressure control valve configured to adjust exhaust efficiency of the gas within the processing container; and
a controller configured to control the gas supply system and the high frequency generating source,
wherein the controller is configured to drive, in a first step, the high frequency generating source at a first energy condition with a first gas and a first radio-frequency (RF) power, and to drive, in a second step, the high frequency generating source at a second energy condition with a second gas and a second RF power, and
wherein, in transitioning from the first step to the second step, the controller is configured to perform a gas switching from the first gas to the second gas right before the transitioning from the first step to the second step, and
in the gas switching, the controller is configured to set a gas flow rate of the first gas to zero and to set an initial gas flow rate of the second gas in an initial period right after the gas switching to be larger than a regular gas flow rate of the second gas after lapse of the initial period, wherein the regular gas flow rate of the second gas is substantially larger than zero, and wherein the controller is further configured to open the automatic pressure control valve to a first angle to reduce a pressure in the processing container in the gas switching and open the automatic pressure control valve to a second angle, which is smaller than the first angle, before lapse of the initial period.
2. The plasma processing apparatus of claim 1 , further comprising an exhaust efficiency adjusting unit configured to adjust exhaust efficiency of the gas within the processing container,
wherein the controller is configured to control the exhaust efficiency adjusting unit to increase the exhaust efficiency in the initial period to be higher than the exhaust efficiency after lapse of the initial period.
3. The plasma processing apparatus of claim 1 , wherein the transitioning from the first step to the second step is performed without an intermediate time period.
4. The plasma processing apparatus of claim 1 , wherein the first RF power is larger than zero.
5. A plasma processing apparatus, comprising:
a processing container;
a gas supply system configured to supply a gas into the processing container;
a high frequency generating source configured to introduce high frequency waves for plasma generation into the processing container;
an exhaust efficiency adjusting unit configured to adjust exhaust efficiency of the gas in the processing container; and
a controller configured to control the gas supply system and the exhaust efficiency adjusting unit,
wherein, upon performing a first step with a first set pressure and a second step with a second set pressure, the second set pressure being different from the first set pressure in the processing container, the controller is configured to set, based on the second set pressure and a set flow rate of the gas supplied from the gas supply system, a target value of exhaust efficiency of the exhaust efficiency adjusting unit which has a correlation with values of the second set pressure and the set flow rate, and to control the exhaust efficiency adjusting unit such that an actual exhaust efficiency becomes the target value of the exhaust efficiency,
wherein the controller performs a feedforward control on the exhaust efficiency adjusting unit based on the target value of the exhaust efficiency adjusting unit in a period for transitioning from the first step to the second step, and performs a feedback control on an actual pressure detected by a pressure sensor after the period for the transitioning from the first step to the second step so as to open the exhaust efficiency adjusting unit to a first angle to reduce a pressure in the processing container when transitioning from the first step to the second step and open the exhaust efficiency adjusting unit to a second angle, which is smaller than the first angle. before the second step is ended.