Techniques to improve critical dimension width and depth uniformity between features with different layout densities

Abstract

Techniques to improve CD width and depth uniformity between features with different layout densities are provided. In one aspect, a method of forming a contact structure includes: patterning features in different regions of a dielectric at different layout densities whereby, due to etch loading effects, the features are patterned to different depths in the dielectric and have different bottom dimensions; depositing a sacrificial spacer into/lining the features whereby some of the features are pinched-off by the sacrificial spacer; opening up the sacrificial spacer at bottoms of one or more of the features that are not pinched-off by the sacrificial spacer; selectively extending the one or more features in the dielectric, such that the one or more features have a discontinuous taper with a stepped sidewall profile; removing the sacrificial spacer; and filling the features with a conductive material to form the contact structure. A contact structure is also provided.

Dependencies are inferred from the claim text.