The invention relates to a method of processing a substrate, having a first surface with a device area and a second surface opposite the first surface, wherein the device area has a plurality of devices formed therein. The method comprises applying a pulsed laser beam to the substrate from the side of the second surface, in a plurality of positions along the second surface, so as to form a plurality of hole regions in the substrate, each hole region extending from the second surface towards the first surface. Each hole region is composed of a modified region and a space in the modified region open to the second surface. The method further comprises grinding the second surface of the substrate, where the plurality of hole regions has been formed, to adjust the substrate thickness.