Diagnostic Method For Locating The Wafer Position In A Crystal
Original Publication Date: 1979-Aug-01
Included in the Prior Art Database: 2005-Feb-20
The position that a wafer occupied in the original as-grown crystal can be determined by means of this method. All crystals are processed so that they have one or more fiducial flats ground into the surface., A notch 1 is ground or scribed across the flat 2 of crystal 3, as shown in Fig. 1. The location of the wafer 4 in the crystal can be determined by measuring the distance, d, of notch 1 from the edge 5 of flat 1, as shown in Fig. 2. The length from the end of crystal 3 is then calculated by simple trigonometry. This variable notch seed/tail wafer identification method is used as a diagnostic tool for engineering purposes.