Patents Assigned to Wacker-Chemtronic Gesellschaft fur Elecktronik-Grundstoffe mbH
  • Patent number: 5351446
    Abstract: Ingot-type semiconductor single crystals having diameters of more than 200 m can be sawed into thin wafers using an annular saw if the crystal is fed towards the cutting edge of the annular saw while rotating around its longitudinal axis. The method includes having a wafer sawed out in this way until a residual joint is created between a wafer and the end face of the ingot. Ingot and wafer are finally separated by means of a residue separation technique which leaves behind various central material projections on the ingot and the wafer. Particularly suitable for residue separation are torsion separation and separation by a wire saw. This procedure reliably prevents the frequently observable, uncontrollable breaking-off of the wafer in the final phase of the annular sawing if this is exclusively used as the method of separation.
    Type: Grant
    Filed: September 1, 1992
    Date of Patent: October 4, 1994
    Assignee: Wacker-Chemtronic Gesellschaft fur Elecktronik-Grundstoffe mbH
    Inventor: Karlheinz Langsdorf