21 August 2014 Three-dimensional step–height measurement using sinusoidal wavelength scanning interferometer with four-step phase-shift method
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Abstract
A sinusoidal wavelength scanning interferometer with the four-step phase-shift method is demonstrated for a three-dimensional profile measurement. The interference phase-shift signal generated by the sinusoidal wavelength scanning contains information about optical path difference covering a nm-μm scale structure. The interference phase-shift signal was obtained by the four-step phase-shifting method. The sinusoidal wavelength shifting with a frequency of approximately 180 Hz and tunable range of 5.7 nm was performed by the Littman–Metcalf external resonator-type tunable laser with a center of 772.1 nm. The full-field surface profile measurement was conducted by a charge coupled device image sensor with an accuracy on a nm scale. The surface profiles of gauge blocks with a step height up to about 10  μm were successfully measured with a surface profile irregularity of 3.8×10−2   μm . The deviations of two measured surfaces of upper and lower steps were estimated to be 1.6×10−2  μm and 3.1×10−2   μm , respectively.
© 2014 Society of Photo-Optical Instrumentation Engineers (SPIE)
Samuel Choi, Samuel Choi, Shouhei Takahashi, Shouhei Takahashi, Osami Sasaki, Osami Sasaki, Takamasa Suzuki, Takamasa Suzuki, } "Three-dimensional step–height measurement using sinusoidal wavelength scanning interferometer with four-step phase-shift method," Optical Engineering 53(8), 084110 (21 August 2014). https://doi.org/10.1117/1.OE.53.8.084110 . Submission:
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