Methods and apparatus for controlling plasma in a plasma processing system
First Claim
1. A method for processing a substrate in a plasma processing chamber having an electrode, said plasma processing chamber having a plurality of RF power supplies coupled to provide a plurality of RF signals to said electrode, comprising:
- pulsing a first one of said plurality of RF power supplies to generate a base RF pulsing signal,wherein said pulsing the first one of said plurality of RF power supplies is performed during the processing of the substrate,wherein said base RF pulsing signal pulses between a high power level and a low power level at a first pulsing frequency, wherein said base RF pulsing signal represents a first RF signal of said plurality of RF signals having a lowest pulsing frequency among pulsing frequencies of said plurality of RF signals, said lowest pulsing frequency being different from an RF frequency of said base RF pulsing signal;
sending a control signal to a second one of said plurality of RF power supplies, wherein said control signal is generated proactively in a manner that does not require sensing, during the processing of said substrate, of a change in one or more chamber parameters due to said pulsing of said first one of said plurality of RF power supplies; and
pulsing the second one of said plurality of RF power supplies, responsive to said control signal, between a first predefined power level and a second predefined power level different from said first predefined power level to generate a non-base pulsing RF signal, wherein said non-base pulsing RF signal represents a second RF signal of the plurality of RF signals, wherein said pulsing the second one of said plurality of RF power supplies is performed during the processing of the substrate, wherein the first and second predefined power levels are predetermined during a calibration operation that occurs before the processing of the substrate to reduce a chance of occurrence of a disturbance in plasma impedance, the disturbance caused when the base RF signal pulses between the high power level and the low power level.
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Abstract
Methods and apparatus for processing a substrate in a multi-frequency plasma processing chamber are disclosed. The base RF signal pulses between a high power level and a low power level. Each of the non-base RF generators, responsive to a control signal, proactively switches between a first predefined power level and a second predefined power level as the base RF signal pulses. Alternatively or additionally, each of the non-base RF generators, responsive to a control signal, proactively switches between a first predefined RF frequency and a second predefined RF frequency as the base RF signal pulses. Techniques are disclosed for ascertaining in advance of production time the first and second predefined power levels and/or the first and second predefined RF frequencies for the non-base RF signals.
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Citations
29 Claims
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1. A method for processing a substrate in a plasma processing chamber having an electrode, said plasma processing chamber having a plurality of RF power supplies coupled to provide a plurality of RF signals to said electrode, comprising:
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pulsing a first one of said plurality of RF power supplies to generate a base RF pulsing signal, wherein said pulsing the first one of said plurality of RF power supplies is performed during the processing of the substrate, wherein said base RF pulsing signal pulses between a high power level and a low power level at a first pulsing frequency, wherein said base RF pulsing signal represents a first RF signal of said plurality of RF signals having a lowest pulsing frequency among pulsing frequencies of said plurality of RF signals, said lowest pulsing frequency being different from an RF frequency of said base RF pulsing signal; sending a control signal to a second one of said plurality of RF power supplies, wherein said control signal is generated proactively in a manner that does not require sensing, during the processing of said substrate, of a change in one or more chamber parameters due to said pulsing of said first one of said plurality of RF power supplies; and pulsing the second one of said plurality of RF power supplies, responsive to said control signal, between a first predefined power level and a second predefined power level different from said first predefined power level to generate a non-base pulsing RF signal, wherein said non-base pulsing RF signal represents a second RF signal of the plurality of RF signals, wherein said pulsing the second one of said plurality of RF power supplies is performed during the processing of the substrate, wherein the first and second predefined power levels are predetermined during a calibration operation that occurs before the processing of the substrate to reduce a chance of occurrence of a disturbance in plasma impedance, the disturbance caused when the base RF signal pulses between the high power level and the low power level. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A method for processing a substrate in a plasma processing chamber having an electrode, said plasma processing chamber having a plurality of RF power supplies coupled to provide a plurality of RF signals to said electrode, comprising:
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pulsing a first one of said plurality of RF power supplies to generate a base RF pulsing signal, wherein said pulsing the first one of said plurality of RF power supplies is performed during the processing of the substrate, wherein said base RF pulsing signal pulses between a high power level and a low power level at a first pulsing frequency, wherein said base RF pulsing signal represents a first RF signal of said plurality of RF signals having a lowest pulsing frequency among pulsing frequencies of said plurality of RF signals, said first pulsing frequency being different from an RF frequency of said base RF pulsing signal; sending a control signal to a second one of said plurality of RF power supplies, wherein said control signal is generated proactively in a manner that does not require sensing, during the processing of said substrate, of a change in one or more chamber parameters due to said pulsing of said first one of said plurality of RF power supplies; and switching an RF frequency output by the second one of said plurality of RF power supplies, responsive to said control signal, between a first predefined RF frequency and a second predefined RF frequency different from said first predefined RF frequency to generate a non-base pulsing RF signal, wherein said non-base pulsing RF signal represents a second RF signal of the plurality of RF signals, wherein said switching the RF frequency output by the second one of said plurality of RF power supplies is performed during the processing of the substrate, wherein the first and second predefined frequencies are predetermined during a calibration operation that occurs before the processing of the substrate to reduce a chance of occurrence of a disturbance in plasma impedance, the disturbance caused when said base RF pulsing signal pulses between the high power level and the low power level. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
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25. A method comprising:
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pulsing a low frequency signal between two power levels, wherein said pulsing of the low frequency signal is performed during processing of a substrate; pulsing a high frequency signal between two levels, the high frequency signal having a frequency higher than a frequency of the low frequency signal, wherein said pulsing of the high frequency signal is performed during the processing of the substrate, wherein said pulsing of the high frequency signal is synchronous to the pulsing of the low frequency signal, wherein the two levels of the high frequency signal include a predefined first level and a predefined second level, wherein the predefined first and second levels of the high frequency signal are defined during a calibration operation that occurs before the processing of the substrate to reduce a chance of occurrence of a disturbance in plasma impedance, the disturbance caused when the low frequency signal pulses between the two power levels. - View Dependent Claims (26, 27, 28, 29)
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Specification