The modified Beckmann–Kirchhoff scattering theory for surface characteristics in-process measurement

This paper focuses on how the scattering theory can be applied to the analysis of the surface characteristics in an in-process optical measurement. The mean scattered intensity distributions from a surface without and with the additional layers are presented based on the modified Beckmann–Kirchhoff scattering theory. The results show that the introduction of the additional layers only affects rough surfaces. The light scattered from a rough surface under the additional layers seems to be scattered from a bare rough surface with a different surface parameter in the small angle approximation. The experiment is conducted with pixel gray value measurement along the main direction of light scattering stripe to verify the theoretical analysis. The experimental curves can well fit the proposed model, which testifies the correction of the modified Beckmann–Kirchhoff scattering theory.