Improved topography measurement with a high dynamic range using phase difference sensing technology.
Opt Lett
; 48(17): 4657-4660, 2023 Sep 01.
Article
em En
| MEDLINE
| ID: mdl-37656579
ABSTRACT
Phase difference sensing technology (PDST) is employed for topography measurement, and two interference structures are proposed to achieve upper-limit adjustment and high resolution in the measurement range a dual-wavelength system with a single Fabry-Perot (FP) cavity and a single-wavelength system with dual FP cavities. The phase difference between the two interference signals is determined by an elliptic fitting algorithm (EFA), and this change in phase difference is utilized to characterize the step height. Experimental results indicate that the measurement upper-limit can be adjusted to either 410â
µm, 187â
µm, or 108â
µm by varying the wavelength difference in the dual-wavelength system, which gives a measurement error of 2.96%. In contrast, while offering a measurement resolution of 3.47â
nm, the single-wavelength system exhibits a measurement error of 5.38%. The proposed method is capable of satisfying the measurement requirements during micro-electromechanical system (MEMS) processing with proficiency.
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MEDLINE
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En
Ano de publicação:
2023
Tipo de documento:
Article