We have studied several factors having an effect on LER in terms of resist chemistry, resist process, CD-SEM metrology, numerical aperture and sigma settings ofthe exposure tool, and the mask pattern. LER is extracted from the developed resist profile. In ArF lithography process, development and rinse process is very critical because ArF resist is relatively hydrophobic compared to KrF resist. It causes heterogeneous interaction at interface of resist and aqueous solution (developer or deionized water). We improved roughness at contact hole pattern by the introduction of wetting process prior to development. Clear and homogeneous rinsing is also needed to remove scum and swelled resist generated at development step. On the other hand, the roughness of mask pattern is one of the important factors of LER on wafer. We confirmed that this global dislocation is a potent influence but local edge roughness ofmask is insignificant to wafer LER. This dislocation ofpattern is originated from the lack of shot accuracy in E-beam writer using variable shaped beam.

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