Crack Detection in Full Size Cz-Silicon Wafers Using Lamb Wave Air Coupled Ultrasonic Testing (LAC-UT)

Abstract

With increasing demand for solar energy, the need for reliable inspection systems has increased tremendously. In this paper, a combination of air coupled ultrasonics and Lamb waves have been utilized to frame a crack detection system. Monocrystalline and polycrystalline silicon wafers of 200 μm thickness were used for experimentation and theoretical Lamb mode dispersion curves were plotted for Lamb wave generation in these wafers. A set of defect-free and cracked samples were scanned and the results are presented in this paper. A complete laboratory based cracked detection system was developed and the demonstrated to detect cracks in silicon wafers.