Arc detection
An arc detection system for a plasma generation system includes a radio frequency (RF) sensor that generates first and second signals based on a respective electrical properties of (RF) power that is in communication with a plasma chamber. A correlation module generates an arc detect signal based on the first and second signals. The arc detect signal indicates whether an arc is occurring in the plasma chamber and is employed to vary an aspect of the RF power to extinguish the arc.
1. An arc detection system for a plasma generation system, comprising:
a radio frequency (RF) sensor that generates first and second signals based on a respective electrical properties of RF power that is in communication with a plasma chamber; and
an analysis module that:
determines an estimation of the RF power based on correlating the first and second signals that is in communication with the plasma chamber for a period based on the first and second signals,
determines a derivative of the estimation of the RF power for the period,
determines whether an arc is occurring in the plasma chamber by comparing an absolute value of the derivative of the estimation of the RF power with a variable threshold, and
if the absolute value of the derivative of the estimation of the RF power is greater than the variable threshold, generates an arc detect signal and determines an estimated energy of the arc based on the first and second signals,
wherein the arc detect signal is employed to vary an aspect of the RF power to extinguish the arc.
2. The arc detection system of claim 1 , wherein the variable threshold is adjusted by a user of the plasma generation system.
3. The arc detection system of claim 1 , wherein the variable threshold is automatically adjusted based on operating conditions of the plasma generation system.
4. The arc detection system of claim 1 , wherein the analysis module stores a plurality of estimations of the RF power for a period.
5. The arc detection system of claim 4 , wherein the variable threshold is automatically adjusted based on at least one of a maximum value of the plurality of estimations of the RF power and a standard deviation of the plurality of estimations of the RF power.
6. The arc detection system of claim 1 , wherein, if the absolute value of the derivative of the estimation of the RF power is equal to the variable threshold, the analysis module generates the arc detect signal and determines the estimated energy of the arc based on the first and second signals.
7. The arc detection system of claim 1 , further comprising a control module that employs the arc detect signal to vary the aspect of the RF power to extinguish the arc.
8. The arc detection system of claim 7 , further comprising an RF generator in communication with a power amplifier control module, wherein the power amplifier control module employs the arc detect signal to modify the RF power output by the RF generator to extinguish the arc without input from the control module.
9. The arc detection system of claim 8 , wherein the power amplifier control module varies the RF power output for an extinguishing period to extinguish the arc without input from the control module based on the arc detect signal.
10. The arc detection system of claim 9 , wherein, if the absolute value of the derivative of the estimation of the RF power is greater than the variable threshold, the analysis module determines an amount by which the absolute value of the derivative of the estimation of the RF power exceeds the variable threshold.
11. The arc detection system of claim 10 , wherein the power amplifier control module varies the RF power output based on the amount.
12. The arc detection system of claim 11 , wherein the power amplifier control module determines the extinguishing period based on the amount.
13. The arc detection system of claim 10 , wherein the power amplifier control module determines the extinguishing period based on the amount.
14. The arc detection system of claim 10 , wherein the variable threshold is automatically adjusted based on operating conditions of the plasma generation system.