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The built-in layer constraint definition oacMinFillPatternSpacing specifies the minimum distance required between metal filler geometries and active geometries. The distance is specified in database units.
This constraint is often a recommendation rather than a hard constraint. It often conflicts with oacMinDensityConstraint and therefore must be relaxed.
| Constraint type: | oaLayerConstraint |
| Value types: | oaIntValue |
| Database types: | oaDesign, oaTech |
| Object types: | oaAppObject |
The following value types are supported by this constraint:
This oaIntValue represents the minimum spacing required between the active and the filler geometries in database units.
Units: DBU
Providing fill-to-active spacing constraints that are larger than the normal minimum spacing constraints help to improve manufacturing yield. Fundamentally, manufacturing yield is worse for metal geometries that are minimally spaced because the possibility of shorts is higher for minimally spaced geometries than it is for geometries that are spaced farther apart. By requiring that the fill metal is "more than minimum spacing" away from active metal, the yield can be improved. In some cases, very large fill-to-active spacing rules (such as ten times minimum spacing) make it impossible to meet the density rules. When this happens, the density rules generally take precedence, and you must reduce the fill-to-active spacing.
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