
IC DfM for Devices and Products 101
Maximum tolerance contours for fully enclosed contacts (e.g., hot aluminum)
would require minimum DRC space checks between the landing pads. For bor-
derless contacts, a DRC needs to prevent an electrical short to the adjacent con-
necting lines.
Cell optimization based on simulation and tolerance contours should help
increase layout density, especially to verify aggressive OPC (scaling of the k
1
factor in the Rayleigh equation down to very low values). For near-wavelength
photolithography, linear shrink of the cell by about 30% (cell area reduction
by 50%) may be possible by applying aggressive OPC to scalab ...