New technique to reconstruct effective 3D profile from tilt images of CD-SEM

This study presents a new and unique method to reconstruct 3D profile from tilt images of SEM for semiconductor device pattern called 'Inverse Stereo Matching'. This method is based on 'the shape from shading' and it’s more stable than the conventional stereo matching method in case of low S/N in sidewall of tilt images, and it is able to reconstruct gradual change of sidewall shape that is difficult for the conventional stereo matching to reconstruct in detail. Additionally, this study presents a new method using 'MPPC Indices' to compensate errors of local shape in reconstruction 3D profile caused by the particular characteristic of secondary electron.