METHOD AND DEVICE FOR DETECTING ARCS

摘要

An arc detecting method and a device are provided to accurately detect arcs at high speed if several reference values are determined in advance. A method for detecting arcs during a plasma process for supplying an output signal of an AC(Alternating Current) generator as power is composed of steps for determining time(t1-t5) indicating that the output signal as an evaluation signal or a signal related to the output signal is over a reference value(R1-R4) in a positive half-wave(30) of the evaluation signal or below the reference value in a negative half-wave of the evaluation signal; deciding following time(t6-t10) indicating that the evaluation signal is below the reference value in the same half-wave of the positive half-wave of the evaluation signal or over the reference value in the negative half-wave of the evaluation signal; deciding at least one time interval(I1-I5) by using at least one of the times; repeating the first, second, and third steps for following half-wave(31) of the evaluation signal; comparing time intervals corresponding to each other; and generating an arc detection signal if the time intervals are different from each other over a pre-determined allowable limit value(T).