The development of an inspection system for defects in silicon crystal growth

This study presents an inspection system to detect the growth defects of silicon crystals that comprise a CCD camera, an LED light source, and power modulation. The defects on multicrystalline silicon can be observed clearly while the silicon wafer were irradiated by the red LED light at a small lighting angle (i.e., 20–30°). However, the growth defects on monocrystalline silicon wafer were difficult to observe because of it low image intensity. And then, the growth defects image was significantly enhanced when the wafer was illuminated by a white LED (WLED) and rotated at a specific angle (i.e., 23°). The experimental results showed that the WLED illumination system made the growth defects more easily observable than did other LED sources (i.e., red, blue, and green LEDs). In addition, the proposed inspection system can be used for on-line fast detection for quality control of monocrystalline silicon wafer.