X-Ray Diffraction Topography-Differential Omega Scanning Technique

Abstract

The Differential Omega Scanning Technique (DOST) was developed to improve topographs obtained from silicon wafers which generally possess process induced flexure during the manufacture of semiconductors products. A commercially available Lang camera has been electronically instrumented to provide an automatic adjustment of omega motion of the specimen on the goniometer axis. The position of the specimen relative to the primary beam (theta) is continually altered by DOST to assure maximum, or near maximum, diffraction intensity with changes of flexure of the wafer as the specimen is scanned. The resulting topographs have near complete images and appear to have improved quality. Using techniques developed within the x-ray laboratory, routine acceptable topographs are obtained in only the time required to scan the diameter of the specimen one time.