The invention relates to a method of processing a workpiece having a first surface, a second surface opposite the first surface, and a third surface extending between the first and second surfaces. The method comprises forming modified regions inside the workpiece so as to create openings in the workpiece. The openings extend to at least one of the first surface, the second surface and the third surface. The method further comprises, after forming the modified regions inside the workpiece, introducing a liquid medium into at least some of the openings and, after introducing the liquid medium into the at least some of the openings, applying an external stimulus to the liquid medium so as to increase the volume of the medium. Moreover, the invention relates to a workpiece processing system for performing this method.