The Phase-stepping Interferometry Algorithm And Experimental Research Of Precision Wafer Testing System

With the rapid development of IC technology, the major semiconductor manufacturers are constantly improving the production technology and expanding the production. A large number of semiconductor chips have been produced. And the corresponding quality problems have also emerged. How to detect the quality of the semiconductor chips online is an important issue for the semiconductor production process.Firstly, the article describes the measurement principle and the common measurement methods. After comparing various kinds of the measurement methods, we make a choice of an advanced measurement method which is polarization interferometer. After that, a detailed study and concluded of the interferometry have done. We think the phase-shifting interferometry is appropriate due to its broad application prospects and superior detection performance. And we have developed a program of testing the wafer.Secondly, we deeply study the phase retrieving algorithm and the phase-unwrapping algorithm. And on this basis, we propose the phase-stepping algorithm insensitive to linear phase error and the phase-unwrapping algorithm using Zernike polynomial fitting. Furthermore, we have in-depth understanding of the image pre-processing, and combined with the advanced digital image processing technology to enable information processing speed to increase.Thirdly, we have done a large number of experiments. Those demonstrate that the phase-stepping algorithm insensitive to linear phase error can eliminate some of the systematic errors, and improve the measurement accuracy. The phase- unwrapping algorithm using Zernike polynomial fitting can restrain the errors which have been produced by system noise. The algorithm of the system has a high-precision, a high accuracy of phase information processing.Finally, by using the application of MATLAB software platform, the phase- processing algorithms have been tested by a large number of experimental verification in this paper. The results demonstrate that the algorithm can effectively improve the interference in image quality,and can accurately collect, analysis, and process phase information. And also restore the object's surface microstructure with high-precision.