Abstract: The amount of dust particles deposited on a semiconductor wafer during plasma etching or CVD in manufacturing a semiconductor integrated circuit is decreased by second plasma generating electrode 28 disposed around a lower electrode 15 in a plasma etching chamber 4a. High frequency voltage is applied to the second plasma generating electrode 18 just before the stop of plasma discharge to form a sub-plasma of high density along the outer periphery of the lower electrode 15, there is formed a sub-potential distribution acting to push out negatively charged dust particles stagnating near the main surface of a semiconductor substrate 7 toward the outer periphery of the wafer. The negatively charged dust particles thus pushed out from the vicinity of the main surface of the wafer 7 are moved to the second plasma generating electrode 28 and exhausted by a vacuum pump through an exhaust port 25.

Abstract: Disclosed is an etching method and an apparatus for performing an etching by alternately and repeatedly switching an average thickness of an ion sheath and an average energy of etching ions between two different values. Since the etchant absorption to the surface of an article to be etched and the etching by ions are effectively performed, it is possible to reduce the influence of an aspect ratio on an etching depth, and hence to perform the etching with an equal depth even if the width of the opening is changed.