| 摘要 |
The thickness t and refractive index n of an incremental thin film layer deposited on a base stack of layers are determined, where the characteristic matrix M of the base stack is <IMAGE> by directing light at a first wavelength toward the layer and the base stack, measuring the reflectance of the first wavelength light from the layer and the base stack, directing light at a second wavelength toward the layer and the base stack, and measuring the reflectance of the second wavelength light from the layer and the base stack. The measured values of reflectance for each wavelength are then substituted in the relationship <IMAGE> where B1=M11Cos phi -(M21/n) Sin phi , B2=Ns(M12Cos phi +(M22/n) Sin phi ), C1=Ns(M22Cos phi -M12nSin phi ), C2=M11nSin phi +M21Cos phi , phi =2 pi nt/ lambda , Ns is the refractive index of the substrate, and lambda is the wavelength at which the reflectance is measured. The thickness t and the refractive index n are determined by solving the two reflectance equations.
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