Method for determining incident angle in measurement of refractive index and thickness

摘要

A method for determining a measured incident angle of a monochromatic light for measurement is applied in the measurement of a refractive index and a thickness of a thin film of a single layer formed on a substrate having a known complex refractive index. This method comprises the steps of measuring a first energy reflection ratio of an S- polarized light or a P-polarized light by a measured sample at various angles of incident of the monochromatic light having a certain wavelength used in the measurement; calculating a second energy reflection ratio of the S- polarized light or the P-polarized light when the monochromatic light is incident to the substrate within an incident medium having a certain refractive index, the second energy reflection ratio being calculated by using the complex refractive index and the refractive index of the incident medium as a function of the incident angle; calculating a second angle satisfying an equation in which the first and second reflection ratios are equal to each other with respect to the S-polarized light or the P-polarized light; and setting an angle except for this second angle as the measured incident angle. The other two incident angle determining methods are shown.