Controlling plasma processing using parameters derived through the use of a planar ion flux probing arrangement
First Claim
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1. A method for controlling a substrate processing process, said substrate processing process being configured to process a substrate using plasma in a substrate processing chamber, comprising:
- providing a PIF (planar ion flux) measurement arrangement, said PIF measurement arrangement including at least a PIF probe that has a surface exposed to a plasma sheath of said plasma while said substrate is processed by said plasma;
alternately creating a charging phase and a quiescent phase for said PIF arrangement using an energy source that is configured to provide energy to said plasma via said PIF probe;
ascertaining a time tpoint2, said time tpoint2 representing a time during said charging phase of said PIF measurement arrangement wherein a first potential difference across said plasma sheath equals to a plasma potential of said plasma;
ascertaining a time tpoint3a, said time tpoint3a representing a time during said charging phase of said PIF measurement arrangement wherein a second potential difference across said plasma sheath equals a floating potential, said floating potential representing a value of a potential difference across said plasma sheath during said charging phase when no current flows through said PIF probe; and
generating a control signal to create at least one of an alarm and a transition in said substrate processing process if a time difference between said time tpoint2 and said time tpoint3a meets a predefined condition.
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Abstract
Methods and apparatus for detecting and/or deriving the absolute values of and/or the relative changes in parameters such as the plasma potential and the ion flux using a Planar Ion Flux (PIF) probing arrangement are disclosed. The detected and/or derived values are then employed to control plasma processing processes.
40 Citations
44 Claims
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1. A method for controlling a substrate processing process, said substrate processing process being configured to process a substrate using plasma in a substrate processing chamber, comprising:
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providing a PIF (planar ion flux) measurement arrangement, said PIF measurement arrangement including at least a PIF probe that has a surface exposed to a plasma sheath of said plasma while said substrate is processed by said plasma; alternately creating a charging phase and a quiescent phase for said PIF arrangement using an energy source that is configured to provide energy to said plasma via said PIF probe; ascertaining a time tpoint2, said time tpoint2 representing a time during said charging phase of said PIF measurement arrangement wherein a first potential difference across said plasma sheath equals to a plasma potential of said plasma; ascertaining a time tpoint3a, said time tpoint3a representing a time during said charging phase of said PIF measurement arrangement wherein a second potential difference across said plasma sheath equals a floating potential, said floating potential representing a value of a potential difference across said plasma sheath during said charging phase when no current flows through said PIF probe; and generating a control signal to create at least one of an alarm and a transition in said substrate processing process if a time difference between said time tpoint2 and said time tpoint3a meets a predefined condition. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method for controlling a substrate processing process, said substrate processing process being configured to process a substrate using plasma in a substrate processing chamber, comprising:
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providing a PIF (planar ion flux) measurement arrangement, said PIF measurement arrangement including at least a PIF probe that has a surface exposed to a plasma sheath of said plasma while said substrate is processed by said plasma; alternately creating a charging phase and a quiescent phase for said PIF arrangement using an energy source that is configured to provide energy to said plasma via said PIF probe; ascertaining a time tpoint2, said time tpoint2 representing a time during said charging phase of said PIF measurement arrangement wherein a first potential difference across said plasma sheath equals to a plasma potential of said plasma; ascertaining a probe bias voltage at said time tpoint2, said probe bias voltage at said time tpoint2 representing a potential difference between said surface of said PIF probe and ground at said at said time tpoint2; and generating a control signal to create at least one of an alarm and a transition in said substrate processing process if said probe bias voltage at said time tpoint2 meets a predefined condition. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
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23. A method for controlling a substrate processing process, said substrate processing process being configured to process a substrate using plasma in a substrate processing chamber, comprising:
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providing a PIF (planar ion flux) measurement arrangement, said PIF measurement arrangement including at least a PIF probe that has a surface exposed to a plasma sheath of said plasma while said substrate is processed by said plasma; alternately creating a charging phase and a quiescent phase for said PIF arrangement using an energy source that is configured to provide energy to said plasma via said PIF probe; ascertaining a time tpoint2, said time tpoint2 representing a time during said charging phase of said PIF measurement arrangement wherein a first potential difference across said plasma sheath equals to a plasma potential of said plasma; ascertaining a probe bias voltage at said time tpoint2, said probe bias voltage at said time tpoint2 representing a second potential difference between said surface of said PIF probe and ground at said at said time tpoint2; ascertaining a time tpoint3a, said time tpoint3a representing a time during said charging phase of said PIF measurement arrangement wherein a second potential difference across said plasma sheath equals a floating potential, said floating potential representing a value of a third potential difference across said plasma sheath during said charging phase when no current flows through said PIF probe; and ascertaining a probe bias voltage at said time tpoint3, said probe bias voltage at said time tpoint3 representing a fourth potential difference between said surface of said PIF probe and said ground at said at said time tpoint3; ascertaining a difference between said probe bias voltage at said time tpoint2 and said probe bias voltage at said time tpoint3; generating a control signal to create at least one of an alarm and a transition in said substrate processing process if said difference between said difference between said probe bias voltage at said time tpoint2 and said probe bias voltage at said time tpoint3 meets a predefined condition. - View Dependent Claims (24, 25, 26, 27, 28, 29, 30, 31, 32, 33)
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34. A method for controlling a substrate processing process, said substrate processing process being configured to process a substrate using plasma in a substrate processing chamber, comprising:
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providing a PIF (planar ion flux) measurement arrangement, said PIF measurement arrangement including at least a PIF probe that has a surface exposed to a plasma sheath of said plasma while said substrate is processed by said plasma; alternately creating a charging phase and a quiescent phase for said PIF arrangement using an energy source that is configured to provide energy to said plasma via said PIF probe; ascertaining a time tpoint2, said time tpoint2 representing a time during said charging phase of said PIF measurement arrangement wherein a first potential difference across said plasma sheath equals to a plasma potential of said plasma; ascertaining a probe bias voltage at said time tpoint2, said probe bias voltage at said time tpoint2 representing a second potential difference between said surface of said PIF probe and ground at said at said time tpoint2; ascertaining a time tpoint3a, said time tpoint3a representing a time during said charging phase of said PIF measurement arrangement wherein a second potential difference across said plasma sheath equals a floating potential, said floating potential representing a value of a third potential difference across said plasma sheath during said charging phase when no current flows through said PIF probe; and ascertaining a probe bias voltage at said time tpoint3, said probe bias voltage at said time tpoint3 representing a fourth potential difference between said surface of said PIF probe and said ground at said at said time tpoint3; ascertaining a difference between said probe bias voltage at said time tpoint2 and said probe bias voltage at said time tpoint3; ascertaining an electron temperature of said plasma using said difference between said probe bias voltage at said time tpoint2 and said probe bias voltage at said time tpoint3 and a effective ion mass value; and generating a control signal to create at least one of an alarm and a transition in said substrate processing process if said electron temperature meets a predefined condition. - View Dependent Claims (35, 36, 37, 38, 39, 40, 41, 42, 43, 44)
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Specification