| dc.description.abstract | This study presents a ＂Single-shot Polarization Interferometric Surface Profilometry Technique＂ that enables precise measurement of the surface topography of a test object. It addresses the limitations encountered in existing semiconductor surface profilometry, such as complex system architecture and restricted measurement range. The proposed technique leverages the polarization interference phenomenon between the reflected light from the test object and a reference surface to perform surface profilometry, eliminating the need for additional electro-optic modulators. When polarization interference occurs, the polarization states of the two reflected beams become orthogonal, and the phase variation in the interference image encodes the topographical information. Through the introduced polarization interference phase-unwrapping algorithm, the phase distribution of the test object can be determined, and by utilizing the surface profilometry equation, the corresponding surface topography can be calculated.
The measurement system developed in this study combines ＂polarization interference＂ with a ＂polarization camera,＂ creating a non-common-path measurement system. This design not only enables the test object to generate interference images but also effectively reduces the complexity of the setup. Simultaneously, it captures the intensity signals from four different polarization directions. In this measurement system, the optical characteristics of the reflecting mirror and the polymer phase retarder are exploited to project the reflected beams onto the imaging system, forming four orthogonal polarization interference images. Compared to phase-shifting interferometry techniques, the proposed system performs surface profilometry without the need for phase modulators or devices that alter the phase difference of the interference images. It only requires the acquisition of a single interference image to calculate the surface topography of the test object, making it suitable for measuring the surface topography of continuously curved surfaces and polished materials with various reflective properties.
In the measurement experiments, the developed measurement technique successfully captured the surface topography distribution of different flat mirrors and silicon carbide wafer samples. The technique′s capability to measure wafer topography was verified by altering the wafer′s position and tilting angle. The system′s resolution was found to reach 11.12 nm, with a maximum detection range of a 60 mm diameter. | en_US |