Method and apparatus for semiconductor wafer cleaning using high-frequency acoustic energy with supercritical fluid

A method for cleaning a wafer, comprising:

• disposing a wafer between a first plurality of transducers and a second plurality of transducers such that the first plurality of transducers are positioned above a top surface of the wafer and such that the second plurality of transducers are positioned below a bottom surface of the wafer,
• wherein the second plurality of transducers mirrors the first plurality of transducers with regard to a geometric configuration of each transducer, and
• wherein the first plurality of transducers is defined in multiple vertically separated levels such that adjacent transducers within the first plurality of transducers are disposed in different ones of the multiple vertically separated levels so as to avoid gaps between adjacent transducers within the first plurality of transducers;
• exposing the wafer to a supercritical fluid;
• and
• activating a pair of mirrored transducers defined by one transducer in the first plurality of transducers and one transducer in the second plurality of transducers so as to generate and transfer acoustic energy through the supercritical fluid to the wafer in a direction extending between the pair of mirrored transducers.

A method for cleaning a wafer, comprising:

• disposing a wafer between a first plurality of transducers and a second plurality of transducers such that the first plurality of transducers are positioned above a top surface of the wafer and such that the second plurality of transducers are positioned below a bottom surface of the wafer,
• wherein each of the first plurality of transducers is mirrored by a transducer in the second plurality of transducers to form a mirrored pair of transducers,
• wherein each transducer in both the first and second pluralities of transducers is defined to have a same surface area size facing the wafer,
• wherein the first plurality of transducers is defined in multiple vertically separated levels above the top surface of the wafer such that adjacent transducers within the first plurality of transducers are disposed in different ones of the multiple vertically separated levels above the top surface of the wafer so as to avoid gaps between adjacent transducers within the first plurality of transducers, and
• wherein the second plurality of transducers is defined in multiple vertically separated levels below the bottom surface of the wafer such that adjacent transducers within the second plurality of transducers are disposed in different ones of the multiple vertically separated levels below the bottom surface of the wafer so as to avoid gaps between adjacent transducers within the second plurality of transducers;
• exposing the wafer to a supercritical fluid;
• and
• cyclically activating each mirrored pair of transducers so as to transfer acoustic energy through the supercritical fluid to different areas the wafer, wherein each of the different areas of the wafer corresponds to activation of a different mirrored pair of transducers.