Patent ID: 7816626

Claim:
A method for severing a disk of brittle material comprising the steps of: forming a crack by introducing thermomechanical stresses by a laser, which crack extends from the upper side of the disk at least into the disk toward the underside and in direction of the desired severing lines; fixing the disk by its underside to a supporting surface of a workpiece holder; moving a laser beam on the upper side or free surface of the disk along the desired severing lines relative to the disk; cooling the disk along the desired severing lines; and carrying out the cooling from the underside of the disk before the application of the laser beam in that the supporting surface of the workpiece holder is cooled and the cooling persists at least until the disk is cooled over its thickness; wherein the cooling is carried out by a means for cooling being provided in the workpiece holder; wherein said means for cooling are cooling channels or grooves through which liquid or gaseous coolant flows and which are arranged under the supporting surface; and wherein said cooling channels are arranged in a pattern identical to a pattern of the planned severing lines, so that the cooling is localized in a narrowly confined manner along the desired severing lines.