DEFECT DENSITY EVALUATION METHOD
Original Publication Date: 1989-Aug-01
Included in the Prior Art Database: 2001-Nov-05
In evaluating the defect density.of epitaxial layers, it is desirable to determine a focal point on the wafer surface as well as accurately defining a known unit of area in which defect density may be calculated. Prior art methods of measuring defect density have included using epitaxial defects and surface particulates as a focal point and then employing the objective lens field of view to determine area. Another prior art method in- cludes employing a template of lint-free paper having a cutout of known area and disposing the template on the surface of a wafer and counting defects within the cutout. However, this method generates particles and also requires that epitaxial defects be employed as focal points.