Method of detecting arc discharges in a plasma process
AssigneeHUETTINGER Elektronik GmbH + Co. KG
InventorsMarkus Winterhalter, Peter Wiedemuth
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Abstract
An arc discharge detection device is used for detecting arc discharges in a plasma process. The arc discharge detection device includes a comparator to which an instantaneous signal and a reference value are supplied. The reference value is formed by a setting means from an extreme value of the signal. The extreme value is determined by an extreme value detection device within a predetermined time period, and the comparator changes the state of an arc discharge detection signal when the comparison between the reference value and an instantaneous value of the signal shows that an arc discharge has occurred.
Claims12
A method of detecting arc discharges in a plasma process, the method comprising:
- determining, using detection circuitry, an extreme value of a signal within a predetermined time period, the extreme value corresponding to a minimum or maximum value of the signal during the predetermined time period;
- comparing a sensed value of the signal, or a value proportional thereto, with the extreme value to determine a difference therebetween;
- and
- detecting an arc discharge based on the difference exceeding a predetermined deviation;
- wherein the signal is proportional to an output voltage or an output current of a DC supply, and wherein filtering is performed for rising and falling signal values using different time constants.
Dependencies are inferred from the claim text.