Achromatic spectroscopie ellipsometer with high spatial resolution

摘要

The invention concerns an achromatic spectroscopic ellipsometer for analysing small regions of a sample ( 1 ) over a wide range of wavelengths from ultraviolet (UV) to infrared (IR). The spectroscopic ellipsometer contains a light source ( 2 ) emitting a light beam ( 3 ). The light beam ( 3 ) goes through a polarisation state generator section ( 4 ) before being focused at an incidence angle q by a first parabolic mirror ( 5 ) to a small spot on sample ( 1 ). A second parabolic mirror ( 6 ) collects the reflected beam ( 16 ) and connects said beam to an analysing section ( 7 ). The reflected beam ( 16 ) emerges from the analysing section ( 7 ) to go to means ( 8 ) for detecting and analysing a spectroscopically said beam. According to the invention, the light beam ( 3 ) through the polarisation state generator section ( 4 ) up to the first parabolic mirror ( 5 ) and the light beam from the second mirror ( 6 ) through the analysing section ( 7 ) are parallel enabling achromatism. The incidence angle q is largely varied without shifting of the location of the small spot on the sample surface.