Method of and apparatus for detecting and controlling in situ cleaning time of vacuum processing chambers
First Claim
1. A method of ending a cleaning process of a vacuum workpiece processing chamber evacuated to a vacuum condition comprising terminating the cleaning process in response to detecting a substantial change in flow rate of gas evacuated from the chamber.
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Accused Products
Abstract
The end of a cleaning process of a vacuum workpiece processing chamber evacuated to a constant pressure vacuum condition is controlled. The chamber is cleaned by exciting a cleaning gas to a plasma state by a field including an electric component. The process is terminated in response to detection of a substantial decrease in the time rate of change of pressure in a foreline of a vacuum pump evacuating the chamber after the plasma electrical impedance has been stabilized. The substantial decrease signals that the chamber is clean. A horn in the chamber that excites the gas to a plasma is indicated as being clean when the plasma electrical impedance is stable. The indication of plasma impedance stabilization is derived by monitoring horn DC bias voltage, or one or both variable reactances of a matching network connected between the horn and an r.f. excitation source for the horn.
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Citations
39 Claims
- 1. A method of ending a cleaning process of a vacuum workpiece processing chamber evacuated to a vacuum condition comprising terminating the cleaning process in response to detecting a substantial change in flow rate of gas evacuated from the chamber.
- 3. A method of ending a cleaning process of a vacuum workpiece processing chamber evacuated to a vacuum condition, the chamber being cleaned by exciting a cleaning gas to a plasma state by a field including an electric component, the method comprising terminating the cleaning process in response to detecting a substantial change in the flow rate of gas evacuated from the chamber after the plasma electrical impedance has been stabilized.
- 20. Apparatus for controlling cleaning of a vacuum workpiece processing chamber evacuated to a vacuum condition, the chamber being cleaned by exciting a cleaning gas to a plasma state by a field including an electric component, the apparatus comprising a sensor for the flow rate of gas evacuated from the chamber, and a controller responsive to the sensor and at least one electrical parameter associated with the plasma impedance for controlling the flow of the cleaning gas to the chamber and the power to the electrode.
- 30. Apparatus for controlling cleaning of a vacuum workpiece processing chamber evacuated to a vacuum condition comprising a sensor for the flow rate of gas evacuated from the chamber, and a controller responsive to the sensor for controlling the power to the electrode and the flow of an etching cleaning agent to the evacuated chamber, the controller turning off power to the electrode and causing the etching cleaning agent to stop flowing to the chamber in response to a substantial change in the flow rate detected by the sensor.
- 32. A method of detecting when a cleaning process of a vacuum workpiece processing chamber evacuated to a vacuum condition has been completed, comprising detecting a substantial change in the flow rate of gas evacuated from the chamber while an etching cleaning agent is being applied to the chamber and the chamber is being evacuated.
- 35. Apparatus for detecting when a cleaning process of a vacuum workpiece processing chamber evacuated to a vacuum condition has been completed, comprising a sensor for the flow rate of gas evacuated from the chamber, and a monitor responsive to the sensor for detecting a substantial change in the flow rate sensed by the sensor while an etching cleaning agent is being applied to the chamber and the chamber is being evacuated.
- 38. A computer storage medium for activating a computer for controlling ending of a cleaning process of a vacuum workpiece processing chamber evacuated to a vacuum condition, the computer being responsive to a signal indicative of a function of flow rate of gas evacuated from the chamber, the storage medium comprising stored signals for commanding the computer to terminate the cleaning process in response to the signal indicating to the computer that there is a substantial change in the flow rate of gas evacuated from the chamber.
Specification