非接觸式電容位移感測器之晶片厚度量測儀器的應用已經有數十年，以非接觸式電容原理設計的精密測量厚度(平坦度)儀器。非接觸式之特點為無磨擦、無損磨和無惰性，且還具有信噪比大、靈敏度高、頻響寬、非線性小、精度穩定性佳等優點，但在使用上有其限制，其限制在於量測超高阻矽晶片特別是〖10〗^5Ω-cm以上之晶片，量測上會有數值誤差值異常現象。非接觸式電容位移感測器之靜電場於量測超高阻(〖10〗^5Ω-cm以上)矽晶片高功率Power裝置晶片通常使用超高阻晶片，以往量測CZ與FZ長晶法成長的超高阻矽晶棒切割之矽晶片，需經過退火RTA(Rapid Thermal Annealing)熱處理程序將矽晶棒內部之摻雜分布更均勻外，經快速退火熱處理程序將阻抗數值降低至低於〖10〗^5Ω-cm，才能透過非接觸式電容感測器厚度(平坦度)量測儀器，量測得準確的平坦度數據，本研究利用光導效應提高導電率，降低其阻抗使超高阻阻抗數值降低至低於〖10〗^5Ω-cm，使得非接觸式電容位移感測器晶片厚度(平坦度)量測儀器，量測數值得到改善其準確性，本研究使用波長廣佈可見光範圍之鹵素燈及指向性高強度集中的可見光雷射光來照射量測區域之矽晶片表面，讀取其數據，實驗結果準確性及穩定性皆有顯著的改善。;Non-contact capacitive disposition sensor on thickness measurement equipment applications have many years then use the non-contact capacitive principle to designed measurement thickness (flatness) gauge. Contactless of features is without friction, non -destructive and non- inertness characteristics. It also has high signal-noise ratio and high sensitive and bandwidth wide, non-linear is small, precision stability better and more benefits. But the still has its limitations, it is limited to a very high resistivity wafer especially it over resistivity 〖10〗^5Ω-cm measurement will have a value is not accurate. Because when non-contact capacitive disposition sensor of the electrostatic field will be pass through the wafer surface on the ultra-high resistivity wafer ( > resistivity 〖10〗^5Ω-cm) would cause measurement is not correct. And high-power device chip typically use FZ within phosphorus atomic or through NTD technology replace silicon to phosphorus for ultra-high resistivity wafer. As well known the high resistivity silicon wafer must be through rapid thermal annealing (RTA) process to uniform inside dopants then also reduce resistivity. So measure it will be accurately. This research used the photo conductive effect to enhance conductivity then reduce the resistivity < 〖10〗^5Ω-cm and improve non-contact capacitive displacement sensors measurement of thickness more accurately. This study used halogen lamp in visible wavelength range and used directive, high intensity, visible laser light irradiating the measurement area of the wafer surface to improve the accuracy and stability of the results.