| 摘要 |
An apparatus for detecting the presence of charged particulate matter in the exhaust line of a semiconductor processing system includes at least two electrodes (10, 12) mounted in the exhaust line. A high voltage power supply (16) maintains an electric field nearly equal to the breakdown field between the first and the second electrodes (10, 12). When charged particulate matter (14) passes through the electric field between the two electrodes (10, 12), the electric field is perturbed so that a transient current pulse flows in a circuit coupled to the two electrodes (10, 12). A pulse current monitoring circuit (18) detects the transient current associated with the passage of the charged particulate matter (14). In some circumstances, it is necessary to precharge the exhausted particulate matter before passing it by the electrodes (10, 12). <IMAGE> |
