| Project/Area Number |
09650041
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Applied optics/Quantum optical engineering
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| Research Institution | Tohoku University |
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Principal Investigator |
YAMAMOTO Masaki Tohoku University, Research Institute for Scientific Measurements, Professor, 科学計測研究所, 教授 (00137887)
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| Project Period (FY) |
1997 – 1998
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| Project Status |
Completed (Fiscal Year 1998)
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| Budget Amount *help |
¥3,400,000 (Direct Cost: ¥3,400,000)
Fiscal Year 1998: ¥1,300,000 (Direct Cost: ¥1,300,000)
Fiscal Year 1997: ¥2,100,000 (Direct Cost: ¥2,100,000)
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| Keywords | spectroscopic ellipsometer / alignment method / perfect cireular polarization / back face reflection / refractive index inhomogeneity / ellipsometry / polarimetry / high accuracy measurement / 高正確度測走 / エキシマレーザー / KrFレーザー / ArFレーザー |
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| Research Abstract |
This project aims to achieve overall accuracy of 0.1% of a rotating analyser ellipsometer (RE) by developing an alignment method to achieve 0.02% precision with production and use of a perfect circular polarization.
Sources of errors in ellipsometry measurements have been attributed to those of instrumental and also of non-instrumental, i.e., the overlapping effect of back reflection and the inappropriate modelling of computer analysis. Procedures were developed for separately detecting the instrumental errors of various origins, which relies upon that in the ideally aligned RE, the output signal should be composed solely of DC component for the perfect circular polarization. In this condition, the residual AC components of the rotation frequency should be attributed to a small winding of a beam combined with uneven detector sensitivity caused by small deviation at the polarizing prism, partial obstruction in the optical path, or other mechanical origin synthesizing to the rotation of the analyser. Other polarization-related origins such as a polarization sensitivity of the analyser prism result in the AC components of doubled frequency. For the correction of imperfect characteristics of the quarter-wave plate, a new method has been developed to measure the phase shift and the relative amplitude transmittance without dismounting the plate. With these corrections, the residual errors estimated by zone extinction differences were reduced to a level of 1/20.
The effects of the back reflection errors and of inhomogeneity of a refractive index normal to the thin film surface have been studied in the measured data. The back reflection error was found to be proportional to the residual elliptically at the reflection conditions of perfect linear polarizations observed periodically as a function of a wavelength. At these condition, the inhomogeneity error was able to be measured quantitatively as the deviations of the azimuthal angles from hose with a bare substrate.
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