Patent ID: 8323420

Claim:
A method for removing material from a semiconductor wafer, comprising: maintaining a pressure within a volume within which a semiconductor wafer resides to be sufficient to maintain a precursor fluid to a non-Newtonian fluid in a liquid state, wherein the precursor fluid is a liquid having a propellant material in a liquid state, and wherein the precursor fluid includes one or more hydrotropes for controlling a size of micelles within the non-Newtonian fluid, wherein the one or more hydrotropes bind to surfaces of the micelles, and wherein the non-Newtonian fluid has a viscosity that changes with an applied shear force; applying the precursor fluid on the semiconductor wafer while maintaining the precursor fluid and propellant material therein in the liquid state, wherein the precursor fluid is disposed proximate to a photoresist crust material to be removed from the semiconductor wafer; allowing the precursor fluid to penetrate through the photoresist crust material to reach vacant regions that underlie the photoresist crust material; and reducing the pressure in the volume to cause the propellant material in the precursor fluid to transform from the liquid state into a gaseous state so as to cause the precursor fluid to transform into the non-Newtonian fluid, whereby an expansion of the precursor fluid during the transformation causes the non-Newtonian fluid to apply mechanical force to the photoresist crust material from within the vacant regions that underlie the photoresist crust material so as to remove the photoresist crust material from the semiconductor wafer.