Patent ID: 7196793

Claim:
An extremely-thin-film measurement and thin-film measurement method for analyzing spectroscopic data acquired from a spectroscopic ellipsometer using best-local-minimum-calculation (BLMC), said method comprising: a spectrum measurement step wherein incident light is cast onto a thin film on a substrate which is to be measured while changing the wavelength of the incident light as a parameter in order to obtain the Ψ E (λ i ) and Δ E (λ i ) spectrums for each wavelength λ i , which represent the change in polarization between the incident light and the reflected light; a step for assuming the complex refractive index (N 0 (n 0 , k 0 )) of said substrate, the complex refractive index (N (n, k)) of said film, based upon the dispersion formula, a plurality of film thicknesses within a plausible range, and a plurality of incident angles within a plausible range; a step for performing fitting for the parameters of the dispersion formula (DSP) based upon combinations of said incident angle and said film thickness; a first analyzing step for selecting fitting results obtained based upon a model formed of a combination of said film thickness and said incident angle, which exhibits the minimal difference between the Ψ M (λ i ) and Δ M (λ i ) obtained by said fitting and said measured Ψ E (λ i ) and Δ E (λ i ); and a second analyzing step for performing fitting for the film thickness and the dispersion formula with the incident angle obtained in said first analyzing step being fixed.