Patent ID: 7307726

Claim:
A method for ellipsometric measurement of a sample with spatial resolution under polarising microscope forming a picture of the sample, wherein: the sample is irradiated by an illuminating beam linearly polarised via an aperture diaphragm, the light reflected by the sample is analysed by a polarizer/analyser, characterised by the relative orientation φ of its polarisation direction relative to that of the polarizer, the intensity reflected is modulated by the relative rotation of the polarisation of the illuminating beam and of the polarizer-analyser, characterised in that: the aperture diaphragm of the illuminating beam is a ring centred on the axis of the beam delineating a single angle of incidence, the average reflected flux φ M (x,y) and its modulation amplitude φ m (x,y) are measured simultaneously at each point of the picture obtained of the sample, the measurements φ M (x,y) and φ m (x,y) are processed in order to deduce therefrom simultaneously at each point of the sample two combinations of the ellipsometric parameters ψ(x,y) and Δ(x,y) and of the reflection coefficient |r s | 2 (x,y) on the basis of the formulae: 1 2 ⁢  r s  2 ⁢ ( 1 + tan 2 ⁢ ψ ) = ϕ M ⁢ ⁢ and ⁢ ⁢ 1 2 ⁢  r s  2 ⁢ ( tan 2 ⁢ ψ - 2 ⁢ ⁢ tan ⁢ ⁢ ψcos ⁢ ⁢ Δ ) = ϕ m the measurements φ M (x,y) and φ m (x,y) are processed in order to deduce therefrom the combination sin(2ψ) cos of the single ellipsometric parameters ψ(x,y) and Δ(x,y) on the basis of the formula: φ m =φ M (1−sin( 2 ψ) cos Δ).