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Optics Express

Optics Express

  • Editor: C. Martijn de Sterke
  • Vol. 20, Iss. 11 — May. 21, 2012
  • pp: 12184–12190

Uncertainty improvement of geometrical thickness and refractive index measurement of a silicon wafer using a femtosecond pulse laser

Saerom Maeng, Jungjae Park, Byungsun O, and Jonghan Jin  »View Author Affiliations

Optics Express, Vol. 20, Issue 11, pp. 12184-12190 (2012)

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We have proposed a modified method to improve the measurement uncertainty of the geometrical thickness and refractive index of a silicon wafer. Because measurement resolution based on Fourier domain analysis depends on the spectral bandwidth of a light source directly, a femtosecond pulse laser having the broad spectral bandwidth of about 100 nm was adopted as a new light source. A phase detection algorithm in Fourier domain was also modified to minimize the effect related to environmental disturbance. Since the wide spectral bandwidth may cause a dispersion effect in the optical parts of the proposed interferometer, it was considered carefully through numerical simulations. In conclusion, the measurement uncertainty of geometrical thickness was estimated to be 48 nm for a double-polished silicon wafer having the geometrical thickness of 320.7 μm, which was an improvement of about 20 times that obtained by the previous method.

© 2012 OSA

OCIS Codes
(120.0120) Instrumentation, measurement, and metrology : Instrumentation, measurement, and metrology
(120.3180) Instrumentation, measurement, and metrology : Interferometry
(140.3538) Lasers and laser optics : Lasers, pulsed

ToC Category:
Instrumentation, Measurement, and Metrology

Original Manuscript: March 7, 2012
Revised Manuscript: April 19, 2012
Manuscript Accepted: May 2, 2012
Published: May 14, 2012

Saerom Maeng, Jungjae Park, Byungsung O, and Jonghan Jin, "Uncertainty improvement of geometrical thickness and refractive index measurement of a silicon wafer using a femtosecond pulse laser," Opt. Express 20, 12184-12190 (2012)

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