The Development Of Real-time Wafer Curvature Measuring Instrument

Because of the existing commercial real-time curvature measuring instrument can not use in the epitaxy on Si squares patterned substrates, a real-time curvature measuring instrument to know more about stress change during the GaN epitaxy growth process on Si patterned substrates is designed and made. The curvature change of wafer during silicon squares patterned substrate epitaxy growth process was obtained at the first time.The problem of the real-time curvature measuring instrument used on Si squares patterned substrates is explained first, and this real-time curvature measuring instrument’s measuring principle and system architecture are introduced. Based on the measuring principle and system architecture, the measurement instrument hardware and software are designed and developed. Then this paper introduces the design scheme and components performance of each hardware function module(including the light path secton, mechanical transmission section and circuit section). Developping of the real-time curvature measuring instrument on the Visual Basic as platform is taken in detailed description. Program design ideas of the stepping motor control section and data fitting section are introduced emphatically. Finally, practical application of the real-time curvature measuring instrument in experiment and production is introduced. The measuring precision is reach to2km-1and it’s no less precision than the similar commercial instrument.From the commissioning and testing result, the real-time curvature measuring instrument successfully assemble in Thomas Swan CCS MOCVD. It’s provide quantifiable data to optimizing epitaxy growth process, tracking stress variation of epitaxy film and improving the uniformity of wavelength.This project supported by national key technology support program (2011BAE32B01), National863plan (2011AA03A101) and Natural Science Foundation of China (61040060) and (51072076).