Scattering Bars (SBs) are sub-resolution, phase or chrome bar-like features placed near the edges of patterns on the reticle. Anti-scattering bars (ASBs) are simply the inverse of SBs and are embedded into the pattern. SBs and ASBs alter the slope of the aerial images of isolated and semi-isolated lines to better match those of densely-nested lines. SBs help maintain adequate depth of focus across pitch to help reduce aberration effects and CD dispersion.
Calibre® OPCsbar™ can add, simulate and verify SBs, while retaining the design hierarchy. Users can implement SBs with Calibre OPCsbar or with a custom Calibre script. Calibre OPCsbar has a sophisticated, priority-based “cleanup” option to help decide which SBs to keep when they overlap.