Patent ID: 6476912
Filing Date: 2002-11-05
Classification: G01B,G01N

Abstract:
A method of measuring a surface form of a semiconductor thin film formed at a surface of a semiconductor substrate, comprising:developing a plurality of models of the semiconductor thin film, the developing of each model comprising preparing a graph representing a relationship between tan &phgr; and measurement wavelengths and a graph representing a relationship between cos &Dgr; and measured wavelengths for said semiconductor film thin, using spectroellipsometry, whereby tan &phgr; is a ratio of an amplitude reflection coefficient of a first polarized light component to an amplitude reflection coefficient of a second polarized light component, and cos &Dgr; is a phase difference between the first polarized light component and the second polarized light component, during the spectroellipsometry; optimizing film thickness of said semiconductor thin film by optimizing a coefficient in a Cauchy model function on a premise that five film layers are laminated on said surface of said semiconductor substrate and values for film thicknesses T1, T2, T3, and T4 and void rates V1, V2, V3 and V4 respectively corresponding to a first layer, a second layer, a third layer and a fourth layer of the five film layers of said semiconductor thin film starting from a side toward said semiconductor thin film surface are ascertained, by fitting the optimized film thickness in said graph representing the relationship between tan &phgr; and measurement wavelengths and said graph representing the relationship between cos &Dgr; and measurement wavelengths; and substituting the values ascertained for film thicknesses T1, T2, T3 and T4 and void rates V1, V2, V3 and V4 in the following expression to calculate a total void rate X X=(T1Ã—V1+T2Ã—V2+T3Ã—V3)/(T1+T2+T3), â€ƒand determining the surface form of said semiconductor thin film based upon a correlation between the total void rate X of each model and a measured total void rate of said semiconductor thin film.