Monitoring a discharge in a plasma process
First Claim
1. A method of monitoring a discharge in a plasma process, the method comprising:
- detecting a first signal profile of a plasma supply signal in a first time range of a first time period of the plasma supply signal, the plasma supply signal being a periodically changing signal supplied to the plasma process;
detecting a second signal profile of the plasma supply signal in a second time range of a second time period of the plasma supply signal, points that the second time range is located in the second time period corresponding to points that the first time range is located in the first time period;
determining a threshold by carrying out a calculation from the first signal profile, a minimum time difference, and a minimum signal amplitude difference, such that the threshold has the minimum time difference in a time direction and the minimum signal amplitude difference in a signal amplitude direction; and
in response to determining that a difference between the first signal profile and the second signal profile is beyond the threshold, generating an identification signal that indicates a state or error in the plasma process.
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Accused Products
Abstract
Devices and methods for monitoring a discharge in a plasma process are provided. An example method includes detecting at least a first signal path of at least one plasma supply signal within at least a first time range within at least one period of the plasma supply signal, detecting at least a second signal path of the at least one plasma supply signal within at least a second time range which is at the point corresponding to the first time range in at least one other period of the plasma supply signal, and generating an identification signal if the second signal path deviates by at least a distance from the first signal path. The distance has a minimum time difference and a minimum signal amplitude difference. The method enables to identify arcs in a very reliable and very rapid manner.
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Citations
24 Claims
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1. A method of monitoring a discharge in a plasma process, the method comprising:
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detecting a first signal profile of a plasma supply signal in a first time range of a first time period of the plasma supply signal, the plasma supply signal being a periodically changing signal supplied to the plasma process; detecting a second signal profile of the plasma supply signal in a second time range of a second time period of the plasma supply signal, points that the second time range is located in the second time period corresponding to points that the first time range is located in the first time period; determining a threshold by carrying out a calculation from the first signal profile, a minimum time difference, and a minimum signal amplitude difference, such that the threshold has the minimum time difference in a time direction and the minimum signal amplitude difference in a signal amplitude direction; and in response to determining that a difference between the first signal profile and the second signal profile is beyond the threshold, generating an identification signal that indicates a state or error in the plasma process. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A plasma discharge monitor for monitoring a discharge in a plasma process, the monitor comprising:
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a signal detector configured to receive a plasma supply signal that is a periodically changing signal supplied to the plasma process, the signal detector being operable to; detect a first signal profile of the plasma supply signal in a first time range of a first time period of the plasma supply signal, and detect a second signal profile of the plasma supply signal in a second time range of a second time period of the plasma supply signal, points that the second time range is located in the second time period corresponding to points that the first time range is located in the first time period; and an identification signal generator configured to; determine a threshold by carrying out a calculation from the first signal profile, a minimum time difference, and a minimum signal amplitude difference, such that the threshold has the minimum time difference in a time direction and the minimum signal amplitude difference in a signal amplitude direction, and generate an identification signal in response to determining that a difference between the first signal profile and the second signal profile is beyond the threshold, the identification signal indicating a state or error in the plasma process. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18)
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19. A plasma process system comprising:
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a power generator configured to supply power to a plasma process with a periodically changing output signal of the power generator as a plasma supply signal; and a plasma discharge monitor for monitoring a discharge in the plasma process, comprising; a signal detector operable to; detect a first signal profile of the plasma supply signal in a first time range of a first time period of the plasma supply signal, and detect a second signal profile of the plasma supply signal in a second time range of a second time period of the plasma supply signal, points that the second time range is located in the second time period corresponding to points that the first time range is located in the first time period; and an identification signal generator operable to; determine a threshold by carrying out a calculation from the first signal profile, a minimum time difference, and a minimum signal amplitude difference, such that the threshold has the minimum time difference in a time direction and the minimum signal amplitude difference in a signal amplitude direction, and generate an identification signal in response to determining that a difference between the first signal profile and the second signal profile is beyond the threshold, wherein the identification signal indicates a state or error in the plasma process. - View Dependent Claims (20, 21)
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22. A method of monitoring a discharge in a plasma process, the method comprising:
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detecting a first signal profile of a plasma supply signal in a first time range of a first time period of the plasma supply signal, the plasma supply signal being a periodically changing signal supplied to the plasma process; detecting a second signal profile of the plasma supply signal in a second time range of a second time period of the plasma supply signal, points that the second time range is located in the second time period corresponding to points that the first time range is located in the first time period; establishing a reference profile from the first signal profile based on a threshold by carrying out a calculation from the first signal profile, a minimum time difference, and a minimum signal amplitude difference, such that the reference profile has the minimum time difference as a first minimum difference from the first signal profile in a time direction and the minimum signal amplitude difference as a second minimum difference from the first signal profile in a signal amplitude direction; in response to determining that the second signal profile reaches the reference profile, determining that a difference between the first signal profile and the second signal profile is beyond the threshold; and in response to determining that the difference between the first signal profile and the second signal profile is beyond the threshold, generating an identification signal that indicates a state or error in the plasma process.
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23. A method of monitoring a discharge in a plasma process, the method comprising:
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detecting a first signal profile of a plasma supply signal in a first time range of a first time period of the plasma supply signal, the plasma supply signal being a periodically changing signal supplied to the plasma process; detecting a second signal profile of the plasma supply signal in a second time range of a second time period of the plasma supply signal, points that the second time range is located in the second time period corresponding to points that the first time range is located in the first time period; selecting a plurality of selection points of the second signal profile; for each of the selection points, placing a respective geometric shape around the selection point, the respective geometric shape having a first dimension representing a minimum time difference in a time direction and a second dimension representing a minimum signal amplitude difference in a signal amplitude direction; comparing the second signal profile with the respective geometric shapes with the first signal profile; in response to determining that a portion of the first signal profile is outside of one of the respective geometric shapes, determining that a difference between the first signal profile and the second signal profile is beyond a threshold; and in response to determining that the difference between the first signal profile and the second signal profile is beyond the threshold, generating an identification signal that indicates a state or error in the plasma process.
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24. A plasma discharge monitor for monitoring a discharge in a plasma process, the monitor comprising:
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a signal detector configured to receive a plasma supply signal that is a periodically changing signal supplied to the plasma process, the signal detector being operable to; detect a first signal profile of the plasma supply signal in a first time range of a first time period of the plasma supply signal, and detect a second signal profile of the plasma supply signal in a second time range of a second time period of the plasma supply signal, points that the second time range is located in the second time period corresponding to points that the first time range is located in the first time period; and an identification signal generator configured to; establish a reference profile from the first signal profile based on a threshold by carrying out a calculation from the first signal profile, a minimum time difference, and a minimum signal amplitude difference, such that the reference profile has the minimum time difference as a first minimum difference from the first signal profile in a time direction and the minimum signal amplitude difference as a second minimum difference from the first signal profile in a signal amplitude direction; determine that a difference between the first signal profile and the second signal profile is beyond the threshold in response to determining that the second signal profile reaches the reference profile; and generate an identification signal in response to determining that the difference between the first signal profile and the second signal profile is beyond the threshold, the identification signal indicating a state or error in the plasma process.
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Specification