Thickness measurement using scanned attenuated total reflection technique

An improved method for determining the thin film thickness in terms of the variation of reflectivity in Attenuated Total Reflection (ATR) is proposed. In which, the correlation of the difference of thin film thickness (Ad) and reflectivity (R) is derived on the basis of Fresnel's formula. in addition, a scanning unit is specially designed to scan the laser beam and detector synchronously. Experimental results indicate that the measurement accuracy is not affected by small fluctuation of the incident angle and the reflectivity change. Moreover, possible applications of this technique in developing the displacement sensor with high sensitivity are also suggested.