A new industrial tool combining VUV spectroscopic ellipsometry and grazing X-ray reflectance to characterize 157 nm structures

Multilayer structures for 157 nm lithography show thinner and thinner layer thickness and are more and more sensitivity to the interface and surface roughness. The metrology of this kind of structure becomes very difficult to achieve with only one single characterization method like spectroscopic ellipsometry as thickness and optical indices are strongly correlated for all optical characterization methods. SOPRA has developed recently an R&D instrument combining spectroscopic ellipsometry and grazing X-ray reflectance and shown that it is very useful for characterizing very thin films. In this paper, we present the next version of this instrument which includes automatic wafer handling, automatic adjustment, mapping stage and control software. Some results related to 157 nm lithography are also presented.