Synchronization between an excitation source and a substrate bias supply
Systems and methods for plasma processing are disclosed. A method includes applying pulsed power to a plasma processing chamber with an excitation source during a first processing step with a first duty cycle and applying, during the first processing step, an asymmetric periodic voltage waveform to a substrate support to produce a first plasma sheath voltage between a substrate and a plasma. Pulsed power is applied to the plasma processing chamber with the excitation source during a second processing step with a second duty cycle and during the second processing step, a different asymmetric periodic voltage waveform is applied to the substrate support to produce a different plasma sheath voltage between the substrate and the plasma.
1. A method for plasma processing, the method comprising:
applying pulsed RF power to a plasma processing chamber with an excitation source at a plurality of pulsing levels each having a frequency and a duty cycle; and
applying, synchronously during the plurality of pulsing levels, an asymmetric periodic voltage waveform with a bias supply to affect a control of a plasma sheath voltage during each of the plurality of pulsing levels.
2. The method of claim 1 , wherein the asymmetric periodic voltage waveform is applied synchronously during the plurality of pulsing levels to produce a constant plasma sheath voltage that is a same magnitude for each of the plurality of pulsing levels.
3. The method of claim 1 , wherein the asymmetric periodic voltage waveform is applied synchronously during the plurality of pulsing levels to produce a time-varying plasma sheath voltage for one or more of the plurality of pulsing levels.
4. The method in claim 1 , wherein the asymmetric periodic voltage waveform is applied synchronously during the plurality of pulsing levels to produce a constant plasma sheath voltage that is a different magnitude for each of the plurality of pulsing levels.
5. The method of claim 1 , wherein the asymmetric periodic voltage waveform is applied synchronously during the plurality of pulsing levels to produce a time-varying plasma sheath voltage for one or more of the plurality of pulsing levels.
6. The method of claim 1 wherein the asymmetric periodic voltage waveform is applied synchronously during the plurality of pulsing levels with a positive or negative time offset with respect to each of the plurality of pulsing levels.
7. The method of claim 3 wherein the asymmetric periodic voltage waveform is applied synchronously during the plurality of pulsing levels with a positive or negative time offset with respect to each of the plurality of pulsing levels.
8. The method of claim 4 where the asymmetric periodic voltage waveform is applied synchronously during the plurality of pulsing levels with a positive or negative time offset with respect to each of the plurality of pulsing levels.
9. The method of claim 5 where the asymmetric periodic voltage waveform is applied synchronously during the plurality of pulsing levels with a positive or negative time offset with respect to each of the plurality of pulsing levels.
10. A plasma processing system, the system comprising:
a bias supply configured to apply and modify an asymmetric periodic voltage waveform to a substrate support to modify a plasma sheath voltage between the plasma and a substrate within a plasma processing chamber; and
at least one controller configured to:
applying pulsed RF power to a plasma processing chamber with an excitation source at a plurality of pulsing levels each having a frequency and a duty cycle; and
applying, synchronously during the plurality of pulsing levels, an asymmetric periodic voltage waveform with a bias supply to affect a control of a plasma sheath voltage during each of the plurality of pulsing levels.
11. The plasma processing system of claim 10 , wherein the at least one controller is configured to control the bias supply to apply the asymmetric periodic voltage waveform synchronously during the plurality of pulsing levels to produce a constant plasma sheath voltage that is a same magnitude for each of the plurality of pulsing levels.
12. The plasma processing system of claim 10 , wherein the at least one controller is configured to control the bias supply to apply the asymmetric periodic voltage waveform synchronously during the plurality of pulsing levels to produce a time-varying plasma sheath voltage for one or more of the plurality of pulsing levels.
13. The plasma processing system of claim 10 , wherein the at least one controller is configured to control the bias supply to apply the asymmetric periodic voltage waveform synchronously during the plurality of pulsing levels to produce a constant plasma sheath voltage that is a different magnitude for each of the plurality of pulsing levels.
14. The plasma processing system of claim 10 , wherein the at least one controller is configured to control the bias supply to apply the asymmetric periodic voltage waveform synchronously during the plurality of pulsing levels to produce a time-varying plasma sheath voltage for one or more of the plurality of pulsing levels.
15. The plasma processing system of claim 10 , wherein the at least one controller is configured to control the bias supply to apply the asymmetric periodic voltage waveform synchronously during the plurality of pulsing levels with a positive or negative time offset with respect to each of the plurality of pulsing levels.
16. A non-transitory computer-readable medium comprising instructions stored thereon, for execution by a processor, or for configuring a field programmable gate array, to perform plasma processing, the instructions including instructions to:
apply pulsed RF power to a plasma processing chamber with an excitation source at a plurality of pulsing levels each having a frequency and a duty cycle; and
apply, synchronously during the plurality of pulsing levels, an asymmetric periodic voltage waveform with a bias supply to affect a control of a plasma sheath voltage during each of the plurality of pulsing levels.
17. The non-transitory computer-readable medium of claim 16 , wherein the asymmetric periodic voltage waveform is applied synchronously during the plurality of pulsing levels to produce a constant plasma sheath voltage that is a same magnitude for each of the plurality of pulsing levels.
18. The non-transitory computer-readable medium of claim 16 , wherein the asymmetric periodic voltage waveform is applied synchronously during the plurality of pulsing levels to produce a time-varying plasma sheath voltage for one or more of the plurality of pulsing levels.
19. The non-transitory computer-readable medium in claim 16 , wherein the asymmetric periodic voltage waveform is applied synchronously during the plurality of pulsing levels to produce a constant plasma sheath voltage that is a different magnitude for each of the plurality of pulsing levels.
20. The non-transitory computer-readable medium of claim 16 , wherein the asymmetric periodic voltage waveform is applied synchronously during the plurality of pulsing levels to produce a time-varying plasma sheath voltage for one or more of the plurality of pulsing levels.
21. The non-transitory computer-readable medium of claim 16 , wherein the asymmetric periodic voltage waveform is applied synchronously during the plurality of pulsing levels with a positive or negative time offset with respect to each of the plurality of pulsing levels.