Research On Wavefront Character And Reconstrution Based On Lateral Shearing Interference

Along with the advance of circuit chips' integration, lithography, which has become a key technique in the manufacturing process of LSI and GSI, has had a significant impact on the development of micro-electronics industry. The aberration of lithography imaging lens is a crucial factor that causes the degradation of image quality, so qualitative research and quantitative measure of the second optical aberrations is of great significance. The lateral shearing interferometer is an important optical interferometer for testing aberrations. It has a lower requirment on measuring conditions than other interferometers because it doesn't need a reference wavefront when measuring. What's more, it is not sensitive to disturbance factors, such as airstreams, temperature, etc, and can measure large-diameter optical components. Thus, the lateral shearing interferograms obtained by measuring aberrations are studied.In this paper, the interferometry technology such as the interferometers used to measure the aberrations, the phase-measuring technology and the common wavefront reconstruction methods are summarized, and furthermore qualitative analysis and quantitative measurement of the aberrations are studied. In order to analyze aberrations qualitatively, a diffract model of centro-symmetrical optical system has been constituted to simulate the diffract pattern of primary aberrations and second aberrations. Then diffract pattern's character of each aberration has been analyzed, and the typical pattern with the value's change is given. In addition, under the principle of optical interference, the parallel light lateral shearing interferograms of primary aberrations and second aberrations are simulated, and the character interferograms of each aberration are analyzed. The results of such analysis can provide evidence for judging which kinds of optical aberrations the optical components have.For the quantitative measure, the wavefronts are reconstructed by using the Zernike polynomial. The shearing interferogram of many optical aberrations is simulated, and has been added with the average noise of different intensity to get the connection of each optical aberration's solving error and noise. And in order to improve the calculation speed, a method for getting optical aberrations has been deduced theoretically and been proved effectively through the ideal instances.