PC-based LED Epi-wafers NDT scanning system Dong Zhanmin Li Shaolin Sun Hongsan (Department of Physics, Tsinghua University, Beijing 100084, China) Abstract: A new smart LED epi-wafers nondestructive scanning system that based on PC was introduced. Using software to analyze, the measurement results of epi-wafers’ key performance parameters could be got immediately. The function of film thickness measurement was added to the system. This PC-based intelligent system could realize LED wafer nondestructive, rapid and accurate on-line scanning. Key words: Epi-wafers test; Photoluminescence; White light interference