Shin-Etsu Handotai Co., Ltd.

Unity Semiconductor Corporation

Kevin Quinquinet

Philippe Gastaldo

Susumu Kuwabara

A method includes: determining height Z1 of a focus by an optical microscope having autofocus function which uses irradiation light of wavelength λ0 to adjust the focus; determining a wavelength λ1 of irradiation light used for obtaining observation image of second thin film; obtaining observation image of second thin film by using irradiation light of the wavelength λ1, while altering heights of the focus with the Z1 as reference point; calculating standard deviation of reflected-light intensity distribution within the observation image, obtaining height Z2 of the focus corresponding to a peak position where standard deviation is greatest, and calculating a difference ΔZ between Z1 and Z2; correcting the autofocus function with ΔZ as a correction value; and using the corrected autofocus function to adjust the focus, obtaining the observation image of the second thin film, and calculating the film thickness distribution from the reflected-light intensity distribution within the observation image.

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Villard Bonnot, France

Kevin Quinquinet