Wet Surface Treatment By Usage of a Liquid Bath Containing Energy Limited Bubbles

An upwardly directed gradient of dropping temperatures is controllably and sustainably created in a wet treatment tank between a cooled and face down workpiece (e.g., an in-process semiconductor wafer) and a lower down heat source. A thermal fluid upwell containing thermally collapsible bubbles is directed from the heat source to the face down workpiece. In one class of embodiments, bubble collapse energies and/or bubble collapse locations are controlled so as to avoid exposing delicate features of the to-be-treated surface to damaging forces. For example, rapid collapse of the thermally collapsible bubbles is caused to occur at a predefined safe distance away from the delicate work face of the workpiece so that the delicate work face is not damaged and yet treatment effective kinetic energies are coupled from the collapsing bubbles to the work face. In one class of embodiments the wet treatment includes ultracleaning of the work face. Cleaning fluids that are essentially free of predefined contaminates are upwelled to the to-be-cleaned surface and potentially contaminated after-flows are convectively directed away from the workpiece so as to prevent recontamination of the workpiece.