Hong-Yi LI, Zhi-Yong TAN, Wen-Jian WAN, Jun-Cheng CAO. Non-destructive thickness measurement with micron level accuracy based on a 4.3-THz quantum-cascade laser[J]. Journal of Infrared and Millimeter Waves, 2024, 43(3): 354
- Journal of Infrared and Millimeter Waves
- Vol. 43, Issue 3, 354 (2024)
Fig. 1. Terahertz homodyne detection system：（a） Schematic of the terahertz light path；（b） Photos of the experimental setup
Fig. 2. The measured terahertz beam spot including both the reference light and the interference fringes
Fig. 3. Schematic diagram of the optical path when the terahertz beam passes through the sample
Fig. 4. Theoretical curves of transmission phase （φ） changing with sample rotation angle （θ） under different thickness （T） conditions
Fig. 5. Thickness measurement results of silicon wafers numbered 1 （a），2 （b），and 3 （c） based on optical microscopes，as well as the measured length of a 1 mm standard microscale plate （d）
Fig. 6. Experimental results of transmission phase （φ） with the rotation angle （θ） after the terahertz light passes through the wafer （1+2） and the wafer （1+2+3）
Fig. 7. Variation of the calculated RMSE with the fitting thickness：（a） wafer （1+2）；（b） wafer （1+2+3）
Fig. 8. Experimental （solid circle） and fitting （solid line） transmission phase with different rotation angle
|
Table 1. The nominal value and measurement results of the thicknes of different silicon wafers
Set citation alerts for the article
Please enter your email address
© Copyright 2018-2021 | Chinese Laser Press. All Rights Reserved 沪ICP备15018463号-20