Hybrid matching network topology
The present disclosure relates to plasma generation systems which utilize plasma for semiconductor processing. The plasma generation system disclosed herein employs a hybrid matching network. The plasma generation system includes a RF generator and a matching network. The matching network includes a first-stage to perform low-Q impedance transformations during high-speed variations in impedance. The matching network includes a second-stage to perform impedance matching for high-Q impedance transformations. The matching network further includes a sensor coupled to the first-stage and the second-stage to calculate the signals that are used to engage the first and second-stages. The matching network includes a first-stage network that is agile enough to tune each state in a modulated RF waveform and a second-stage network to tune a single state in a RF modulated waveform. The plasma generation system also includes a plasma chamber coupled to the matching network.
1. A method, comprising:
determining a presence of RF waves that exceeds a first pre-determined threshold;
calculating a first value representing a magnitude and phase relationship of voltage and current;
based on the first value, tuning a second-stage matching network of a hybrid matching network;
calculating a second value representing an impedance from the calculated magnitude and phase relationship of the voltage and current; and
based on the second value, tuning a first-stage matching network of the hybrid matching network.
2. The method of claim 1 , further comprising allowing for the simultaneous execution of parallel control loops, the parallel control loops being associated with the first-stage matching network and the second-stage matching network, which simultaneous execution directs the first-stage matching network and the second-stage matching network of the hybrid matching network to achieve shorter system tuning times.
3. The method of claim 1 , wherein, when the first-stage matching network is disengaged, the first-stage matching network functions as a filter.
4. The method of claim 1 , further comprising configuring a state of a plurality of switch terminals within the first-stage matching network as part of engaging the first-stage matching network.
5. The method of claim 1 , wherein the first-stage matching network is engaged when an input impedance to the second-stage matching network enters a tunable range of the first-stage matching network.
6. The method of claim 1 , wherein operation of the first-stage matching network and the second-stage matching network occurs either independently, simultaneously, or sequentially.
7. The method of claim 1 , wherein the tuning of the second stage matching network is offset relative to a characteristic impedance of a system in order to optimize a secondary tuning goal.
8. The method of claim 7 , wherein the secondary tuning goal is to minimize a transformation Q of the first stage matching network.
9. The method of claim 7 , wherein the secondary tuning goal is to increase or decrease the Q of an entire hybrid matching system.
10. The method of claim 7 , wherein the secondary tuning goal is to maximize a usable tuning range of the first stage matching network.
11. A method, comprising:
determining a presence of a plurality of radio frequency (RF) waves that exceed a first pre-determined threshold;
calculating a first value representing a magnitude and phase relationship of forward power and reflected power;
based on the first value, tuning a second-stage matching network of a hybrid matching network;
calculating a second value representing an impedance from the calculated magnitude and phase relationship of the forward power and the reflected power; and
based on the second value, tuning a first-stage matching network of the hybrid matching network.
12. The method of claim 11 , further comprising allowing for the simultaneous execution of parallel control loops, the parallel control loops being associated with the first-stage matching network and the second-stage matching network, which simultaneous execution directs the first-stage matching network and the second-stage matching network of the hybrid matching network to achieve shorter system tuning times.
13. The method of claim 11 , wherein, when the first-stage matching network is disengaged, the first-stage matching network functions as a filter.
14. The method of claim 11 , further comprising configuring a state of a plurality of switch terminals within the first-stage matching network as part of engaging the first-stage matching network.
15. The method of claim 11 , wherein the first-stage matching network is engaged when an input impedance to the second-stage matching network enters a tunable range of the first-stage matching network.
16. The method of claim 11 , wherein operation of the first-stage matching network and the second-stage matching network occurs either independently, simultaneously, or sequentially.
17. The method of claim 11 , wherein tuning of the second stage matching network is offset relative to a characteristic impedance of a system in order to optimize a secondary tuning goal.
18. The method of claim 17 , wherein the secondary tuning goal is to minimize a transformation Q of the first stage matching network.
19. The method of claim 17 , wherein the secondary tuning goal is to increase or decrease the Q of an entire hybrid matching system.
20. The method of claim 17 , wherein the secondary tuning goal is to maximize a usable tuning range of the first stage matching network.