Olympus USPM-RU-W Series Operation Manual page 88

loaded spectral reflection factor value data and the spectral reflection factor value data R
measured with the materials coated.
(2) Fourier transform method: [FFT]
This method is used to calculate film thickness from the periodicity of the measured
spectral reflection factor value data. Film thickness can be obtained with noise minutely
influenced when it is difficult to detect peaks and valleys in a peak-valley method. This
method is effective for the analysis of single- and multi-layer films. The number of layers
for layer setting must be set to the number of layers for the sample to be treated. Set the
refractive index of each layer for layer setting when obtaining physical film thickness. As
in a peak-valley method, however, this method cannot be used when two or more peaks
and valleys do not exist in the analysis range.
(3) Curve fit method: [FIT]
This method is used to calculate film thickness by presuming the film configuration so
that the difference between the measured spectral reflection factor value data and the
reflection factor value data calculated based on a certain film configuration is the
minimum. Film thickness can be obtained even when two or more peaks and valleys do
not exist in [Range]. This method is effective for the analysis of single- and multi-layer
films. The number of layers, the thickness of layers, an extinctive index, and a refractive
index must be set for layer setting. Since they are used as the initial values of analysis,
the analysis result may vary depending on the setting. This method does not guaranteed
absolute values because it has local solutions.
PV8959-F4E005
1 R
n
c
1 R
: Refractive index of coat materials
n
c
: Refractive index of substrate
n
b
......... (6-4)
n
b
35