Plasma processing apparatus and plasma processing method
According to one embodiment, a plasma processing apparatus includes a processing chamber, a sample stage that is disposed inside the processing chamber and electrically divided into a plurality of regions on which a sample is placed, an electromagnetic wave introduction unit that introduces electromagnetic waves into the processing chamber, and a bias power applying unit that applies bias power to the sample stage, in which the bias power applying unit is configured to include a first radio frequency power applying unit that applies first radio frequency power to a first region out of the plurality of electrically divided regions of the sample stage, a second radio frequency power applying unit that applies second radio frequency power to a second region out of the plurality of electrically divided regions of the sample stage, and a phase adjuster that controls the first radio frequency power applying unit and the second radio frequency power applying unit to shift the phases of the first radio frequency power and the second radio frequency power by a predetermined amount.
1. A plasma processing apparatus comprising:
a processing chamber in which a sample is subject to plasma processing;
a radio frequency power source that supplies radio frequency power for generating plasma;
a sample stage that includes a first region and a second region which are electrically divided from each other and on which the sample is placed, the first region comprising a center electrode and the second region comprising a ring-shaped outer electrode disposed at an outer peripheral side of said center electrode;
a first radio frequency power source that supplies first radio frequency power to the first region;
a second radio frequency power source that supplies second radio frequency power to the second region;
a control device that controls a phase difference which is a difference between a phase of the first radio frequency power and a phase of the second radio frequency power; and
an inter-electrode circuit portion that is disposed between a first transmission path for supplying the first radio frequency power to the first region and a second transmission path for supplying the second radio frequency power to the second region,
wherein one connection portion of the inter-electrode circuit portion is connected between the sample stage and a matching unit of the first radio frequency power source,
the other connection portion of the inter-electrode circuit portion is connected between the sample stage and a matching unit of the second radio frequency power source, and
the control device controls the phase difference so that a voltage difference, which is a difference between a peak-to-peak voltage of a radio frequency voltage applied to the first region and a peak-to-peak voltage of a radio frequency voltage applied to the second region has a peak-to-peak voltage adjustment range that is greater than a peak-to-peak voltage adjustment range in an absence of the phase difference.
2. The plasma processing apparatus according to claim 1 ,
wherein the inter-electrode circuit portion includes an inductance.
3. The plasma processing apparatus according to claim 1 , further comprising:
a first monitor unit that monitors a phase of the first radio frequency power between the one connection portion and the sample stage; and
a second monitor unit that monitors a phase of the second radio frequency power between the other connection portion and the sample stage,
wherein the control device controls the phase difference based on the phase monitored by the first monitor unit, the phase monitored by the second monitor unit, and the predetermined value.
4. The plasma processing apparatus according to claim 1 ,
wherein the control device controls the phase difference such that the phase difference becomes a phase difference corresponding to the predetermined value obtained based on a correlationship between the voltage difference and the phase difference.