Deep-ultraviolet scatterometry for nanoparticle detection

摘要

The detection of surface particles is an important part of contamination control in semiconductor manufacturing. However, the minimum particle size required to be detected has been becoming smaller as integrated-circuit geometries shrink. Current visible-light detection systems can detect particles down to around 50 nm in polytyrene-latex-equivalent size and so are adequate for current geometries, but in the near future even particles as small as around 20 nm in diameter will become significant contaminants. This is beyond the capability of current visible-light scanners, but previous work has shown that deep ultraviolet scattering by such particles should be sufficient to enable their detection. Consequently we have constructed a deep/vacuum ultraviolet scatterometer capable of measuring scattering from semiconductor samples.