SCMOS Layout Rules - CAP_TOP_METAL
for SCMOS_DEEP (and SUBM)



The CAP_TOP_METAL layer is used exclusively for the construction of metal-to-metal capacitors. The bottom plate of the capacitor is one of the regular metal layers, as specified below. CAP_TOP_METAL is the upper plate of the capacitor; it is sandwiched physically between the bottom plate metal and the next metal layer above, with a thin dielectric between the bottom plate and the upper (CAP_TOP_METAL) plate.

The CAP_TOP_METAL can only be contacted from the metal above; the bottom plate metal can be contacted from below or above (subject, in either case, to rule 28.5), and/or by bottom metal extending outside of the capacitor region (rule 28.7). Use of all (legal) upward vias within that region should be maximized. CAP_TOP_METAL must always be contained entirely within the bottom plate metal.


Process Bottom Plate Top Plate Top Plate Contact
TSMC_025 METAL4 CAP_TOP_METAL VIA4 and METAL5
TSMC_018 METAL5 CAP_TOP_METAL VIA5 and METAL6


Rule Description Lambda
SCMOS SUBM DEEP
28.1 Minimum Width, Capacitor n/a 40 45
28.2 Minimum Spacing (2 capacitors sharing a single bottom plate) n/a 12 14
28.3 Minimum bottom metal overlap (including dummy shapes) n/a 4 5
28.4 Minimum overlap of via n/a 3 3
28.5 Minimum spacing to bottom metal via n/a 4 5
28.6 Minimum bottom metal overlap of its via n/a 2 2
28.7 Rule applicability region extends beyond bottom plate n/a 25 25
28.8 Minimum width, dummy shapes (having no vias) n/a 4 5
28.9 Minimum bottom plate to other bottom plate metal n/a 8 9
28.10 Minimum via separation, on CAP_TOP_METAL n/a 20 23
28.11 Minimum (upward) via separation on bottom metal n/a 40 45
28.12 Maximum CAP_TOP_METAL width and length n/a 30 um
28.13 Maximum bottom metal plate width and length n/a 35 um
28.14 No vias from bottom plate downward, directly under top plate CAP_TOP_METAL; dummy metal shapes under capacitor region, discouraged.
28.15 No active or passive circuitry under capacitor region