Design and Assessment of Phase-Shifting Algorithms in Optical Interferometer

Silicon wafers and transparent glass plates are major components in the semiconductor industry. In semiconductor devices, the surface shape and optical thickness of the wafers and glass plates are the key parameters for the optimal performance of the devices. Phase-shifting interferometry has been widely used to achieve precision measurements of these parameters. The phase-shifting algorithm significantly affects the interferometric measurement results with phase-shifting interferometry. In this review, we introduce the design and assessment of phase-shifting algorithms in the Fizeau interferometer. Section 2 categorized the phase-shifting algorithms designed by several methods in terms of their error compensation ability. Then, the optical setup of the Fizeau interferometer used for surface and thickness measurement is explained in Sect. 3. In addition, Sect. 4 explained the principle of phase extraction using phase-shifting interferometry and discussed its error sources. Moreover, design methods for the phase-shifting algorithm to eliminate error sources are introduced in Sect. 5. Finally, the error compensation abilities of designed algorithms are estimated by several methods in Sect. 6.