Claims
- 1. A method for measuring a refractive index of an uppermost thin film of multilayered thin films formed on a substrate comprising the steps of:
- (a) irradiating a P-polarized monochromatic light and an S-polarized monochromatic light on said multilayered thin films at a predetermined angle of incidence;
- (b) measuring intensities of said P-polarized and S-polarized monochromatic lights reflected on said multilayered thin films;
- (c) determining respectively a reflectance R.sub.p of said reflected P-polarized monochromatic light and a reflectance R.sub.s of said reflected S-polarized monochromatic light on the basis of said measured intensities of said P-polarized and S-polarized monochromatic lights;
- (d) determining a phase change 2.beta..sub.p of said irradiated P-polarized monochromatic light, which phase change 2.beta..sub.p is caused during double transversals of said irradiated P-polarized monochromatic light in said uppermost thin film, as a function of said refractive index of said uppermost thin film n.sub.2 by using a known wavelength of said P-polarized monochromatic light .lambda., said predetermined angle of incidence .theta..sub.1 a known refractive index of said substrate n.sub.s, known refractive indices of thin films other than said upper most thin film n.sub.3, n.sub.4 . . . n.sub.m, known thicknesses of said films other than said uppermost thin film d.sub.3, d.sub.4 . . . d.sub.m, and said determined reflectance R.sub.p, to thereby obtain a function of 2.beta..sub.p =P(n.sub.2);
- (e) determining a phase change 2.beta..sub.s of said irradiated S-polarized monochromatic light, which phase change 2.beta..sub.s is caused during double traversals of said irradiated S-polarized monochromatic light in said uppermost thin film, as a function of said refractive index of said uppermost thin film n.sub.2 by using said wavelength .lambda., said predetermined angle of incidence .theta..sub.1, said refractive index n.sub.s, said refractive indices n.sub.3, n.sub.4 . . . n.sub.m, said thicknesses d.sub.3, d.sub.4 . . . d.sub.m and said determined reflectance R.sub.s, to thereby obtain a function of 2.beta..sub.s =S(n.sub.2); and
- (f) determining a value of n.sub.2 which satisfies the following equation as a value of said refractive index of said uppermost thin film, P(n.sub.2)=S(n.sub.2).
- 2. An apparatus for measuring a refractive index of an uppermost thin film of multilayered thin films formed on a substrate comprising:
- means for irradiating a P-polarized monochromatic light and an S-polarized monochromatic light on said multilayered thin films at a predetermined angle of incidence;
- light detecting means disposed on a n optical path of said P-polarized and S-polarized monochromatic lights for receiving said P-polarized and S-polarized monochromatic lights reflected on said multilayered thin films, and for issuing respectively a first signal representing an intensity of said received P-polarized monochromatic light and a second signal representing an intensity of said received S-polarized monochromatic light; and
- calculation means electrically connected to said light detecting means for receiving said first and second signals to thereby determine a reflectance R.sub.p of said P-polarized monochromatic light and a reflectance R.sub.s of said S-polarized monochromatic light on the basis of said received first and second signals, for determining a phase change 2.beta..sub.p of said irradiated P-polarized monochromatic light, which phase change 2.beta..sub.p is caused during double transversals of said irradiated P-polarized monochromatic light in uppermost thin film, as a function of said refractive index of said uppermost thin film n.sub.2 by using a known wavelength of said P-polarized monochromatic light .lambda., said predetermined angle of incidence .theta..sub.1, a known refractive index of said substrate n.sub.s, known refractive indices of thin films other than said uppermost thin film n.sub.3, n.sub.4 . . . n.sub.m, known thicknesses of said thin films other than said uppermost thin film d.sub.3, d.sub.4 . . . d.sub.m, and said determined reflectance R.sub.p, to thereby obtain a function of 2.beta..sub.p =P(n.sub.2), for determining a phase change 2.beta..sub.s of said irradiated S-polarized monochromatic light, which phase change 2.beta..sub.s is caused by during double traversals of said irradiated S-polarized monochromatic light in said uppermost thin film, as a function of said refractive index of said uppermost thin film n.sub.2 by using said wavelength .lambda., said predetermined angle of incidence .theta..sub.1, said refractive index n.sub.s, said refractive indices n.sub.3, n.sub.4 . . . n.sub.m, said thicknesses of d.sub.3, d.sub.4 . . . d.sub.m and said predetermined reflectance R.sub.s, to thereby obtain a function of 2.beta..sub.s =S(n.sub.2), and for determining a value of n.sub.2 which satisfies the following equation as a value of said refractive index of said uppermost thin film, P(n.sub.2)=S(n.sub.2).
Priority Claims (3)
Number |
Date |
Country |
Kind |
63-25128 |
Feb 1988 |
JPX |
|
63-228199 |
Sep 1988 |
JPX |
|
63-228200 |
Sep 1988 |
JPX |
|
CROSS-REFERENCES TO RELATED APPLICATION
This application is a Continuation-in-part application of U.S. Ser. No. 07/256,991 filed on Oct. 13, 1988, now allowed.
Non-Patent Literature Citations (1)
Entry |
Ruiz-Urbieta et al., "Methods for Determining Film Thickness and Optical Constants of Films and Substrates", J. Opt. Soc. Amer., vol. 61, pp. 351-359, 3/1971. |
Continuation in Parts (1)
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Number |
Date |
Country |
Parent |
256991 |
Oct 1988 |
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