Precise plasma control system
Some embodiments include a plasma system comprising: a plasma chamber, an RF plasma generator, a bias generator, and a controller. The RF plasma generator may be electrically coupled with the plasma chamber and may produce a plurality of RF bursts, each of the plurality of RF bursts including RF waveforms, each of the plurality of RF bursts having an RF burst turn on time and an RF burst turn off time. The bias generator may be electrically coupled with the plasma chamber and may produce a plurality of bias bursts, each of the plurality of bias bursts including bias pulses, each of the plurality of bias bursts having an bias burst turn on time and an bias burst turn off time. In some embodiments the controller is in communication with the RF plasma generator and the bias generator that controls the timing of various bursts or waveforms.
1. A plasma system comprising:
a plasma chamber;
an RF plasma generator electrically coupled with the plasma chamber, the RF plasma generator produces a plurality of RF bursts, each of the plurality of RF bursts including RF waveforms, each of the plurality of RF bursts having an RF burst turn on time and an RF burst turn off time;
a bias generator electrically coupled with the plasma chamber, the bias generator produces a plurality of bias bursts, each of the plurality of bias bursts including bias pulses, each of the plurality of bias bursts having an bias burst turn on time and an bias burst turn off time, wherein the bias generator includes an energy recovery circuit; and
a controller in communication with the RF plasma generator and the bias generator that controls the timing of the RF burst turn on time, the RF burst turn off time, the bias turn on time, and the bias turn off time.
2. The plasma system according to claim 1 , wherein the plurality of RF bursts produce and/or drive a plasma within the plasma chamber and the plurality of bias bursts accelerate ions within the plasma.
3. The plasma system according to claim 1 , further comprising an electrode disposed within the plasma chamber, the electrode coupled with the RF plasma generator.
4. The plasma system according to claim 1 , further comprising an inductive antenna disposed within the plasma chamber, the antenna coupled with the RF plasma generator.
5. The plasma system according to claim 1 , further comprising an electrode disposed within the plasma chamber, the electrode coupled with the bias generator.
6. The plasma system according to claim 1 , wherein the RF burst turn on time precedes the bias burst turn on time by less than about 10 ms.
7. The plasma system according to claim 1 , wherein the bias burst turn on time occurs about 10 cycles of the RF waveform after the RF burst turn on time.
8. The plasma system according to claim 1 , wherein the bias burst turn on time precedes the RF burst turn off time by less than about 10 ms.
9. The plasma system according to claim 1 , wherein the difference between the RF burst turn on time and the RF burst turn off time is less than about 1 ms.
10. The plasma system according to claim 1 , wherein the difference between the bias burst turn on time and the bias burst turn off time is less than about 10 ms.
11. The plasma system according to claim 1 , wherein the bias pulses have a pulse repetition frequency greater than 1 kHz.
12. The plasma system according to claim 1 , wherein the bias pulses have a voltage greater than 1 kilovolt.
13. The plasma system according to claim 1 , wherein the RF waveforms has a frequency between 10 kHz and 100 MHz.
14. The plasma system according to claim 1 , wherein the RF waveforms has a frequency of 13.56 MHz.
15. The plasma system according to claim 1 , wherein the controller controls the timing of the RF burst turn on time, the RF burst turn off time, the bias turn on time, and the bias turn off time based on feedback from the plasma chamber.
16. The plasma system according to claim 1 , wherein the bias generator includes a bias compensation circuit.
17. The plasma system according to claim 1 , wherein the RF plasma generator comprises either a full bridge circuit or a half bridge circuit and a resonant circuit.
18. The plasma system according to claim 1 , wherein the bias generator comprises a nanosecond pulser.
19. The plasma system according to claim 1 , wherein the bias generator comprises an RF generator.
20. A method comprising:
driving a plasma chamber with an RF plasma generator with a frequency greater than 10 MHz;
pausing for a first period of time;
pulsing the plasma chamber with a bias generator with pulses having a first voltage at pulse frequency greater than 1 kHz;
pausing for a second period of time, wherein the first period of time is less than the second period of time;
stopping the driving of the RF plasma generator;
pausing for a third period of time; and
stopping the pulsing of the bias generator.
21. The method according to claim 20 , further comprising:
pausing for a fourth period of time;
driving the RF plasma generator;
pausing for the first period of time;
pulsing the bias generator with pulses having a second voltage;
pausing for the second period of time;
stopping the driving of the RF plasma generator;
pausing for the third period of time; and
stopping the pulsing of the bias generator.
22. The method according to claim 21 , wherein the second voltage is greater than the first voltage.
23. The method according to claim 20 , further comprising:
pausing for a fourth period of time;
driving the RF plasma generator;
pausing for a fifth period of time that is different than the first period of time;
pulsing the bias generator with pulses having a second voltage;
pausing for the sixth period of time that is different than the first period of time;
stopping the driving of the RF plasma generator;
pausing for the seventh period of time that is different than the first period of time; and
stopping the pulsing of the bias generator.
24. The method according to claim 20 , wherein:
the first period of time is less than about 10 ms;
the second period of time is less than about 10 ms; and
the third period of time is less than about 10 ms.