Plasma processing based on bias supply reporting
A generator to provide a source waveform, and a controller configured to receive a signal indicative of power reflected to the generator, receive timing information from a bias supply, and provide a report of the impedance based upon the bias waveform information.
1 . A system comprising:
a generator to provide a first waveform; and
a controller configured to:
receive a signal indicative of power reflected to the generator;
receive timing information from a bias supply, wherein the timing information is indicative of when a ramp of a bias waveform of the bias supply is occurring; and
provide a report indicative of the power reflected to the generator during the ramp of the bias waveform based upon the timing information.
2 . The system of claim 1 further comprising at least one sensor to provide the signal indicative of the power reflected to the generator.
3 . The system of claim 1 wherein the controller comprises an input port to receive the signal indicative of the power reflected to the generator from an external sensor.
4 . The system of claim 1 wherein the signal indicative of the power reflected to the generator comprises a measured parameter indicative of a plasma impedance presented to the generator via a match network.
5 . The system of claim 1 , wherein the generator comprises a radio frequency amplifier and the controller comprises a processor and a non-transitory computer-readable storage medium comprising instructions embodied thereon, the instructions are executable by the processor, and the instructions comprise instructions for adjusting the first waveform applied by the radio frequency amplifier based upon the signal indicative of the power reflected to the generator while a ramp voltage provided by the bias supply is occurring or providing the report of the power reflected to the generator while the ramp voltage is occurring.
6 . The system of claim 1 , wherein:
the signal indicative of the power reflected to the generator comprises one or more of:
a measured magnitude of plasma impedance;
a measured reflection coefficient of power reflected;
a measured voltage standing wave ratio (VSWR);
a measured forward power;
a measured delivered power;
a measured voltage;
a measured current; and
a measured phase.
7 . A system comprising:
a bias supply configured to apply a bias waveform, the bias waveform comprising a peak voltage and a ramp voltage;
a generator to apply a first waveform; and
at least one controller configured to:
receive an impedance indicator indicative of an impedance coupled to the generator;
receive timing information from the bias supply, wherein the timing information is indicative of when a ramp of a bias waveform of the bias supply is occurring; and
provide a report of the impedance during the ramp of the bias waveform based upon the timing information.
8 . The system of claim 7 wherein:
the at least one controller is configured to direct the bias supply to adjust a slope of the ramp voltage of the bias waveform to induce the impedance coupled to the generator to be constant, or approximately constant, during an application of the ramp voltage.
9 . The system of claim 7 , wherein:
the at least one controller is configured to determine a non-fluctuating portion of the impedance indicator and to direct the generator to control the non-fluctuating portion to be constant, or approximately constant, during an application of the ramp voltage of the bias waveform.
10 . The system of claim 7 , wherein:
the at least one controller is further configured to extract a non-fluctuating portion of the impedance indicator.
11 . The system of claim 7 , wherein:
the at least one controller is further configured to direct the bias supply to control a duration of the ramp voltage based on the impedance indicator.
12 . The system of claim 7 , wherein:
the impedance indicator comprises one or more of:
a measured magnitude of plasma impedance;
a measured reflection coefficient of power reflected;
a measured voltage standing wave ratio (VSWR);
a measured forward power;
a measured delivered power;
a measured voltage;
a measured current; and
a measured phase.
13 . The system of claim 7 wherein the bias supply is further configured to provide an asymmetric periodic voltage waveform, comprising:
a first section that begins with a first negative voltage, followed by an increase to the peak voltage, followed by a decrease to a second negative voltage; and
a second section that begins with the second negative voltage and includes the ramp voltage between the second negative voltage and a third negative voltage.
14 . A non-transitory computer-readable storage medium comprising instructions embodied thereon, wherein the instructions are executable by a processor and/or capable of programming a field programmable gate array, the instructions comprising instructions for:
providing a bias waveform with a bias supply, wherein the bias waveform includes a peak voltage and a ramp voltage;
applying radio frequency power with a source generator;
receiving a signal indicative of power reflected to the source generator;
receiving timing information from the bias supply, wherein the timing information is indicative of when the ramp voltage is occurring;
obtaining, using the timing information, a measure of the power reflected to the source generator while the ramp voltage is occurring; and
controlling the radio frequency power based upon the measure of the power reflected to the source generator while the ramp voltage is occurring.
15 . The non-transitory computer-readable storage medium of claim 14 wherein the instructions comprise instructions to provide a report of the power reflected to the source generator while the ramp voltage is occurring.
16 . The non-transitory computer-readable storage medium of claim 14 wherein the instructions comprise instructions to provide a report of the power reflected to the source generator based on measurements over an entire cycle of the bias waveform.
17 . The non-transitory computer-readable storage medium of claim 14 wherein the instructions comprise instructions to control the ramp voltage of the bias waveform based on the power reflected to the source generator.
18 . The non-transitory computer-readable storage medium of claim 14 , wherein
the power reflected to the source generator is a measured parameter indicative of a plasma impedance presented to the source generator; and
the power reflected to the source generator is measured during application of the ramp voltage.
19 . The non-transitory computer-readable storage medium of claim 14 , wherein the instructions comprise instructions for:
adjusting a slope of the ramp voltage to induce the power reflected to the source generator to be constant, or approximately constant, during an application of the ramp voltage.
20 . The non-transitory computer-readable storage medium of claim 14 , wherein the instructions comprise instructions for:
extracting a non-fluctuating portion of the power reflected to the source generator corresponding with an application of the ramp voltage; and
adjusting a slope of the ramp voltage to induce the non-fluctuating portion of the power reflected to the source generator to be constant, or approximately constant, during an application of the ramp voltage.