A new machine for the automatic position-dependent orientation measurement of at-cut quartz wafers

A new X-ray machine has been designed which allows the automatic cutting-angle measurement at a nearly arbitrary number of inspection points along the surface of large AT-cut quartz wafers and the corresponding sorting of these wafers. The measurement is based on the /spl Omega/-Scan Method combined with a laser-reflection registration and provides additionally the amount of the XX' miscutting angle and data about the surface topography. Sorting criteria to be qualified by the user may be all these values as well as their spreads or standard deviations. The sorting part of the machine will be specified for the actual wafer dimensions. Capacity (up to a few thousand wafers) and cycle time (e.g., 1 minute per wafer) depend on the wafer size and the number of inspection points.