The effects of development parameter on line edge roughness in sub-0.20 /spl mu/m line patterns

As a pattern size decreases, CD control gets more important. However, the line edge roughness consumes the error budget of critical dimension and has obstructed the development of the high contrast resist to extend the resolution limit of KrF lithography. To investigate the effect of the development parameter on line edge roughness, we observed the profile of the exposed and developed top surface. In the early state of development, the protrusion and extraction of clusters affect dominantly on surface roughness. And then the effect of intrinsic aggregate gradually gets larger as the development time increases. For this reason the linewidth fluctuation decreased as development time increased. The clusters/aggregates are extracted in full dissolution of surrounding polymers and partially dissolved, then these partially dissolved clusters/aggregates are precipitated in DI rinse and rebond on patterns.