Combining the determination of single and mutual, preset preserving, impedance loads with advances in single and double sensor calibration techniques in the application of single and pairwise calibration of sensors
AssigneeAdvanced Energy Industries, Inc.
InventorFrederick Winter
Life of this patent
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Abstract
This disclosure describes systems, methods, and apparatus for calibrating sensors used by a match network during tuning of power delivery to a plasma processing chamber. The calibration can include self-calibration of two sensors in isolation relative to a self-load, and Relative or Absolute mutual calibration of both sensors used together across a mutual load. The mutual calibration can determine errors between the two sensors after they are each calibrated in isolation, and this additional calibration provides previously unrealized tuning accuracy.
Claims20
A match network configured for impedance matching a radio frequency power generator to a plasma processing chamber, the match network comprising:
- a match input;
- an output;
- and
- a plasma return input;
- a first sensor coupled to a first electrical path between the match input and the output;
- a second sensor coupled to a second electrical path between the plasma return input and a ground connection;
- a memory storing a first calibration matrix, K1, a second calibration matrix, K2, and a modified second calibration matrix, K2′;
- a controller configured to monitor power delivery to the plasma processing chamber via the first and second sensors, wherein data from the first or second sensor is calibrated via the first calibration matrix, K1, and data from the second or first sensor, respectively, is calibrated via the modified second calibration matrix, K2′,
- wherein the modified second calibration matrix, K2′, accounts for errors between the first and second sensors when the first and second sensors are calibrated by measuring current and voltage at the output and the plasma return input with a mutual load coupled between the first and second sensors.
A match network configured for impedance matching a radio frequency power generator to a plasma processing chamber, the match network comprising:
- a match input;
- an output;
- and
- a plasma return input;
- a first sensor coupled to a first electrical path between the match input and the output;
- a second sensor coupled to a second electrical path between the plasma return input and a ground connection;
- a memory storing a first calibration matrix, K1, a second calibration matrix, K2, a first modified calibration matrix, K1′, and a second modified calibration matrix, K2′;
- a controller configured to monitor power delivery to the plasma processing chamber via the first and second sensors, wherein data from the first sensor is calibrated via a first modified calibration matrix, K1′, and data from the second sensor is calibrated via a second modified calibration matrix, K2′,
- wherein the modified first calibration matrix, K1′, and the modified second calibration matrix, K2′, account for errors between the first and second sensors when the first and second sensors are individually calibrated via a reference sensor and a self-load, and then mutually calibrated against each other via (1) measurements of current and voltage at the match output by the first sensor and the reference sensor or (2) measurements of current and voltage at the plasma return input by the second sensor and the reference sensor.
Dependencies are inferred from the claim text.