US Patent 7666689 Method to remove circuit patterns from a wafer

A method holds wafers that contain patterned structures using a particle blasting tool. Next, the method directs particles at the patterned structures, such that the particles contact the patterned structures with a predetermined velocity and remove the patterned structures. This process of directing the particles at the wafer is controlled to stop directing the particles when substantially all of the patterned structures are removed from the wafer. This process also comprises selecting the particles to have a size equal to or less than 3 microns. For example, the particles can comprise aluminum oxide, silicon oxide, cerium, and/or a plastic. By maintaining the particle size equal to 3 microns or less, the blasting produces a substantially smooth wafer surface, thereby omitting the need for subsequent wafer polishing. Further, the wafers produced by such processing do not exhibit the highly stress lattice and fragile nature of wafers processed by wet processing.