A high-speed whitelight scanning interferometer using On-The-Fly imaging and parallel processing

Abstract

White light scanning interferometer is one of effective optical measurement systems for high-precision industries. However, its major disadvantages are the slow image-capturing speed for the interferogram acquisition and the high computational cost for the peak-detecting signal process. Here, first a new image acquiring method to reduce the image capturing time is proposed, which is called ‘On-The-Fly imaging system’. During a vertical scanning motion of whitelight scanning interferometer, 2D images of interference fringe are sequentially acquired at a series of given vertical positions without conventional stepwise motions. Second, to reduce the calculation time, a parallel computing method to link multiple PCs is proposed. These two methods were implemented for high-speed WSI and evaluated for on-line inspection to Semiconductor manufacturing process.