Detecting and preventing instabilities in plasma processes
First Claim
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1. A method for reducing instabilities in a plasma-based processing system, the method comprising:
- applying power to a plasma with a power amplifier;
obtaining samples indicative of an impedance of the plasma;
determining a frequency of instability oscillations, resulting from plasma-power amplifier interaction, that are present in the plasma by analyzing the samples to identify oscillatory variations in the plasma impedance; and
altering, based upon the frequency of instability oscillations that are present, an impedance of a load that is experienced by the power amplifier to reduce any instability oscillations in the plasma, the load experienced by the power amplifier including at least an impedance of the plasma, and altering the impedance of the load includes altering a frequency of the power that is applied to the plasma by the power amplifier.
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Abstract
Systems, methods and apparatus for reducing instabilities in a plasma-based processing system are disclosed. An exemplary method includes applying power to a plasma with a power amplifier; determining whether low frequency instability oscillations are present or high frequency instability oscillations are present in the plasma; and altering, based upon whether high or low frequency instability oscillations are present, an impedance of a load that is experienced by the power amplifier, the load experienced by the power amplifier including at least an impedance of the plasma.
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Citations
12 Claims
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1. A method for reducing instabilities in a plasma-based processing system, the method comprising:
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applying power to a plasma with a power amplifier; obtaining samples indicative of an impedance of the plasma; determining a frequency of instability oscillations, resulting from plasma-power amplifier interaction, that are present in the plasma by analyzing the samples to identify oscillatory variations in the plasma impedance; and altering, based upon the frequency of instability oscillations that are present, an impedance of a load that is experienced by the power amplifier to reduce any instability oscillations in the plasma, the load experienced by the power amplifier including at least an impedance of the plasma, and altering the impedance of the load includes altering a frequency of the power that is applied to the plasma by the power amplifier. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A system for reducing instabilities in a plasma-based processing system, the system comprising:
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a power amplifier configured to apply power to a plasma processing chamber to ignite and sustain a plasma; a sensor configured to sense at least one characteristic indicative of an impedance of the plasma; a stability controller configured to obtain samples of the at least one sensed characteristic and determine a frequency of instability oscillations that are present in the plasma by analyzing the samples to identify oscillatory variations in the plasma impedance, and responsive to the frequency of instability oscillations that are present in the plasma, the stability controller controls an operating frequency of the power amplifier to control a load impedance that is experienced by the power amplifier to reduce any instability oscillations in the plasma. - View Dependent Claims (8, 9, 10)
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11. An apparatus for reducing instabilities in a plasma-based processing system, the apparatus comprising:
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a measurement component configured to provide measurements that are indicative of an impedance of the plasma; an instability detection component configured to obtain samples of the measurements, determine a frequency of instability oscillations in the plasma impedance by analyzing the samples, and provide a signal indicative of the frequency of any instability oscillations that are present in the plasma; and a frequency controller in communication with the instability detection component, the frequency controller configured to generate, based upon the frequency of any instability oscillations, a frequency control signal which controls an output frequency of an amplifier so that the frequency of power that is output by the amplifier alters an impedance of a load experienced by the amplifier so as to reduce any instabilities in the plasma-based processing system. - View Dependent Claims (12)
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Specification