18 August 1997 Phase-shifting interferometer for surface inspection
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Proceedings Volume 3185, Automatic Inspection and Novel Instrumentation; (1997) https://doi.org/10.1117/12.284036
Event: ISMA '97 International Symposium on Microelectronics and Assembly, 1997, Singapore, Singapore
A phase-shifting Twyman-Green interferometer has been constructed. Using three consecutively captured interferograms, the phase profile of a reflective surface can be determined. Results using various fringe processing techniques are compared. These methods include uniform averaging, Gaussian mask and spin filtering. For simulated fringes superimposed with random noise and fixed-pattern noise, it has been observed that a combination of weighted averaging and spin filtering could generate the best results. The computerized system has been applied to the measurement of the form errors of a silicon wafer and a cosmetic mirror, respectively. The root-mean-square error of the wafer is determined to be 11.13 nm.
© (1997) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Siu Chung Tam, Siu Chung Tam, Beng-Yew Low, Beng-Yew Low, Hock-Chuan Chua, Hock-Chuan Chua, Anthony Tung Shuen Ho, Anthony Tung Shuen Ho, Wah-Peng Neo, Wah-Peng Neo, } "Phase-shifting interferometer for surface inspection", Proc. SPIE 3185, Automatic Inspection and Novel Instrumentation, (18 August 1997); doi: 10.1117/12.284036; https://doi.org/10.1117/12.284036

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