Matching network characterization using variable impedance analysis
Embodiments of a method of calculating the equivalent series resistance of a matching network using variable impedance analysis and matching networks analyzed using the same are provided herein. In one embodiment, a method of calculating the equivalent series resistance of a matching network includes the steps of connecting the matching network to a load; measuring an output of the matching network over a range of load impedances; and calculating the equivalent series resistance of the matching network based upon a relationship between the measured output and the load resistance. The load may be a surrogate load or may be a plasma formed in a process chamber.
1. A method for characterizing a matching network, comprising:
connecting the matching network to a load;
measuring an output of the matching network over a range of load impedances to obtain a plurality of measured outputs; and
calculating the equivalent series resistance of the matching network based upon a relationship between the plurality of measured outputs and a corresponding plurality of load resistance resistances over the range of load impedances.
2. The method of claim 1 , wherein the load is a variable impedance surrogate load.
3. The method of claim 2 , wherein the surrogate load comprises a tunable circuit capable of generating a desired range of impedances.
4. The method of claim 1 , wherein the load is a plasma formed in a process chamber.
5. The method of claim 4 , further comprising:
varying the impedance of the plasma by selectively controlling parameters of the process chamber.
6. The method of claim 5 , wherein the selectively controlled parameters comprise at least one of temperature, power, frequency, resistance, or pressure.
7. The method of claim 5 , further comprising:
determining whether the matching network needs repair or replacement by comparing the calculated equivalent series resistance of the matching network to a previously determined range of acceptable equivalent series resistance values.
8. The method of claim 1 , further comprising:
evaluating the condition of the matching network based upon the calculated effective resistance.
9. The method of claim 1 , wherein the step of calculating the equivalent series resistance further comprises:
generating a linear regression plot of the plurality of matching network measured outputs versus the corresponding plurality of load resistance.
10. The method of claim 1 , wherein the step of calculating the equivalent series resistance further comprises:
determining a polynomial expression describing the plurality of matching network measured outputs as a function of the corresponding plurality of load resistance.
11. The method of claim 1 , wherein each measured output of the matching network is current.
12. The method of claim 1 , wherein each measured output of the matching network is a metric proportional to current.
13. The method of claim 1 , wherein the range of load impedances spans across a tuning space for the matching network.
14. A method for characterizing a matching network, comprising:
connecting the matching network to a variable impedance surrogate load;
measuring an output of the matching network over a range of load impedances to obtain a plurality of measured outputs;
calculating the equivalent series resistance of the matching network based upon a relationship between the plurality of measured outputs and a corresponding plurality of load resistances over the range of load impedances; and
evaluating the condition of the matching network based upon the calculated effective resistance.
15. The method of claim 14 , wherein the calculating step further comprises:
generating a linear regression plot of the plurality of matching network measured outputs versus the corresponding plurality of load resistances.
16. The method of claim 14 , wherein the step of calculating the equivalent series resistance further comprises:
determining a polynomial expression describing the plurality of matching network measured outputs as a function of the corresponding plurality load resistance.
17. The method of claim 14 , wherein each matching network measured output is current or a metric proportional to current.
18. The method of claim 14 , wherein the evaluating step further comprises:
comparing the calculated equivalent series resistance to a predetermined acceptable resistance level.
19. The method of claim 18 , further comprising:
accepting, rejecting, and/or grouping the matching network in response to the comparing step.