Plasma processing apparatus and plasma processing method
Provided are a plasma processing apparatus with a radio-frequency power supply supplying temporally modulated intermittent radio-frequency power which can be controlled with high precision in a wide repetition frequency band, and a plasma processing method using the plasma processing apparatus. A plasma processing apparatus includes: a vacuum vessel; a plasma generating section plasma in the vacuum vessel; a stage installed in the vacuum vessel and mounted with a sample; and a radio-frequency power supply applying temporally modulated intermittent radio-frequency power to the stage, wherein the radio-frequency power supply has two or more different frequency bands and temporally modulates the radio-frequency power by a repetition frequency which has the same range of analog signals used in each of the frequency band.
1. A plasma processing apparatus, comprising:
a vacuum chamber in which a sample is plasma processed;
a first radio-frequency power supply supplying a first radio frequency power to generate a plasma;
a sample stage on which the sample is mounted;
a second radio-frequency power supply supplying a second radio-frequency power to the sample stage; and
a control device comprising an input section, a microcomputer, and a D/A converter, wherein the control device is configured to convert a repetition frequency of a pulse for time-modulating the second radio-frequency power to a first analog value corresponding to a first frequency band of the repetition frequency and a second analog value corresponding to a second frequency band of the repetition frequency, the second frequency band being wider than the first frequency band of the repetition frequency;
wherein the second radio-frequency power supply includes:
an A/D converter having a plurality of output ports thereon, the A/D converter configured to receive the first analog value and the second analog value, and to convert the first analog value and the second analog value transmitted by the control device to a first digital signal and a second digital signal, respectively, wherein the A/D converter is further configured to output the first digital signal on the first output port and to output the second digital signal on the second output port;
a signal processor constructed at least in part of hardware configured to select the first output port on which is output the first digital signal converted by the A/D converter or the second output port on which is output the second digital signal converted by the A/D converter based on a channel switching signal received by the signal processor from the control device, wherein said channel switching signal corresponds to the first and second digital signals, and wherein said channel switching signal is based on the second radio-frequency power; and
a pulse generator configured to generate pulses having a repetition frequency corresponding to the first digital signal or the second digital signal selected by the signal processor.
2. The plasma processing apparatus according to claim 1 , wherein at least one of the first and second radio-frequency power supplies includes at least as many radio-frequency power supplies as a number of the two or more different frequency bands.
3. A plasma processing apparatus, comprising:
a vacuum chamber in which a sample is plasma processed;
a first radio-frequency power supply supplying a first radio-frequency power to generate a plasma;
a sample stage on which the sample is mounted;
a second radio-frequency power supply supplying a second radio-frequency power to the sample stage;
a control device comprising an input section, a microcomputer, and a D/A converter, wherein the control device is configured to convert a repetition frequency of a pulse for time-modulating the first radio-frequency power to a first analog value corresponding to a first frequency band of the repetition frequency and a second analog value corresponding to a second frequency band of the repetition frequency, the second frequency band being wider than the first frequency band of the repetition frequency;
wherein the first radio-frequency power supply includes:
an A/D converter having a plurality of output ports thereon, the A/D converter configured to receive the first analog value and the second analog value, and to convert the first analog value and the second value transmitted by the control device to a first digital signal and a second digital signal, respectively, wherein the A/D converter is further configured to output the first digital signal on the first output port and to output the second digital signal on the second output port;
a signal processor constructed at least in part of hardware configured to select the first output port on which is output the first digital signal converted by the A/D converter or the second output port on which is output the second digital signal converted by the A/D converter based on a channel switching signal received by the signal processor from the control device, wherein said channel switching signal corresponds to the first and second digital signals, and wherein said channel switching signal is based on the first radio-frequency power; and
a pulse generator configured to generate pulses having a repetition frequency corresponding to the first digital signal or the second digital signal selected by the signal processor.
4. The plasma processing apparatus according to claim 1 , wherein the second radio-frequency power supply includes at least as many radio-frequency power supplies as a number of the two or more different frequency bands.