Wide Range and Accurate Measurement of Wafer Thickness Gauge Using Optical Spectral Analyzer

Applicability of a generic optical spectrum analyzer that is familiar with laser experiments is investigated for on-site wafer thickness measurements in the thinning process, to resolve the issues regarding mismatch in the thickness range of previous thickness measurement system. The optimizations in terms of the spectral range, the spectral resolution and the dynamic range are successfully conducted by use of the optical spectrum analyzer. Owing to both high spectral resolution and wide dynamic range in near infrared spectral measurements, full range thickness measurements for the initial thickness 775μm and the terminal thickness 1μm and nanometer order accuracy are implemented.

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Effect of waveguide optical scattering on the integrated optical spectrum analyzer dynamic range

IEEE Journal of Quantum Electronics ◽

10.1109/jqe.1978.1069811 ◽

1978 ◽

Vol 14 (6) ◽

pp. 437-443 ◽

Cited By ~ 32

Author(s):

J. Boyd ◽

D. Anderson

Keyword(s):

Optical Spectrum ◽

Dynamic Range ◽

Spectrum Analyzer ◽

Optical Scattering ◽

Optical Spectrum Analyzer ◽

Integrated Optical

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A coma-free super-high resolution optical spectrometer using 44 high dispersion sub-gratings

Scientific Reports ◽

10.1038/s41598-020-80307-z ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Hua-Tian Tu ◽

An-Qing Jiang ◽

Jian-Ke Chen ◽

Wei-Jie Lu ◽

Kai-Yan Zang ◽

...

Keyword(s):

High Resolution ◽

Spectral Resolution ◽

Wavelength Region ◽

Ultra Violet ◽

High Spectral Resolution ◽

Visible Range ◽

High Dispersion ◽

Charge Coupled Device ◽

Wide Range ◽

High Resolution Spectrometer

AbstractUnlike the single grating Czerny–Turner configuration spectrometers, a super-high spectral resolution optical spectrometer with zero coma aberration is first experimentally demonstrated by using a compound integrated diffraction grating module consisting of 44 high dispersion sub-gratings and a two-dimensional backside-illuminated charge-coupled device array photodetector. The demonstrated super-high resolution spectrometer gives 0.005 nm (5 pm) spectral resolution in ultra-violet range and 0.01 nm spectral resolution in the visible range, as well as a uniform efficiency of diffraction in a broad 200 nm to 1000 nm wavelength region. Our new zero-off-axis spectrometer configuration has the unique merit that enables it to be used for a wide range of spectral sensing and measurement applications.

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Investigation of Rayleigh-Assisted Coherent Optical Spectrum Analyzer

10.1109/ogc52961.2021.9654372 ◽

2021 ◽

Author(s):

Hong Dang ◽

Linqi Chen ◽

Huanhuan Liu ◽

Jinna Chen ◽

Luoyuan Liao ◽

...

Keyword(s):

Optical Spectrum ◽

Spectrum Analyzer ◽

Optical Spectrum Analyzer

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Differential absorption lidar measurements of water vapor by the High Altitude Lidar Observatory (HALO): Retrieval framework and validation

10.5194/amt-2021-229 ◽

2021 ◽

Author(s):

Brian J. Carroll ◽

Amin R. Nehrir ◽

Susan Kooi ◽

James Collins ◽

Rory A. Barton-Grimley ◽

...

Keyword(s):

Water Vapor ◽

High Altitude ◽

Dynamic Range ◽

Precipitable Water ◽

Spatiotemporal Variability ◽

High Spectral Resolution ◽

Atmospheric Conditions ◽

Differential Absorption ◽

Differential Absorption Lidar ◽

Wide Range

Abstract. Airborne differential absorption lidar (DIAL) offers a uniquely capable solution to the problem of measuring water vapor (WV) with high precision, accuracy, and resolution throughout the troposphere and lower stratosphere. The High Altitude Lidar Observatory (HALO) airborne WV DIAL was recently developed at NASA Langley Research Center and was first deployed in 2019. It uses four wavelengths at 935 nm to achieve sensitivity over a wide dynamic range, and simultaneously employs 1064 nm backscatter and 532 nm high spectral resolution lidar (HSRL) measurements for aerosol and cloud profiling. A key component of the WV retrieval framework is flexibly trading resolution for precision to achieve optimal data sets for scientific objectives across scales. A technique for retrieving WV in the lowest few hundred meters of the atmosphere using the strong surface return signal is also presented. The five maiden flights of the HALO WV DIAL spanned the tropics through midlatitudes with a wide range of atmospheric conditions, but opportunities for validation were sparse. Comparisons to dropsonde WV profiles were qualitatively in good agreement, though statistical analysis was impossible due to systematic error in the dropsonde measurements. Comparison of HALO to in situ WV measurements onboard the aircraft showed no substantial bias across three orders of magnitude, despite variance (R2 = 0.66) that may be largely attributed to spatiotemporal variability. Precipitable water vapor measurements from the spaceborne sounders AIRS and IASI compared very well to HALO with R2 > 0.96 over ocean and R2 = 0.86 over land.

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