Abstract: A method and apparatus for megasonic cleaning of semiconductor wafers. The wafer is positioned so that the surface to be cleansed is parallel to and faces the radiating surface of a quartz or similar resonator which receives sonic waves through a liquid medium from a transducer. The sonic waves striking the wafer are preferably at about a 5° to 30° offset angle from a normally directed wave to the plane of the wafer. The layered medium is gasified and serves to couple the transducer to the resonator. A layer of degasified cleaning fluid is positioned between the resonator and the wafer.

Abstract: A method and apparatus for megasonic cleaning of substrates by placing the wafers in the far-field megasonic zone to eliminate sonic-induced damage to highly sensitive small-scale device structures that occurs in the near-field megasonic zone. Folded acoustic beam paths are defined by at least one reflector to achieve sufficient path length to the wafers. A reciprocally rotating reflector may be used to sweep the acoustic beam across the substrate surfaces.