本論文提出以掃描式白光干涉技術量測光學薄膜之厚度、折射率以及色散常數。薄膜反射光譜可藉由白光干涉圖之傅立葉振幅而推得，並利用基因演算法反推薄膜光學常數。在未知的薄膜特性，利用基因演算法以全域式之搜尋方法，求得最佳的數值解。並針對在量測傅立葉振幅可能造成之誤差來源，包括波數精準性以及光源在時間和空間上的變化，進行研究和改善。隨著誤差的減少和演算法的改進，量測光學薄膜厚度和折射率的結果與橢圓偏振儀比較，其差異皆在 1%以內。搭配白光干涉儀量測大範圍的反射振幅和單點薄膜之特性，可以快速重建二維的薄膜厚度，並且延伸至量測多層膜之厚度。A method to measure thin film thickness, refractive index and dispersion constants based on white light interferometry is described. The thin film property is retrieved from the Fourier amplitude of the white light correlogram and genetic algorithms with elitism to avoid falling into the local minimum due to the parameter convergence and maintain the capability to search the global minimum solution. Besides, the sources of errors in Fourier amplitude, which include the accuracy of wave-number, light source variation in time, and illumination non-uniformity, are investigated. With all these errors reduced, the film thicknesses and refractive indices of four samples measured by white light interferometry are within 1% of the ellipsometry results. As the accuracy of measurement improved, the amplitude based method could be capable to measure thickness profiler of thin-film as well as multi-layer films.
