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The built-in oacMinArea layer constraint specifies the minimum metal area required for non-rectangular polygon shapes in database units squared. Minimum area rules most often apply to via contacts, especially for stacked vias.
To specify the minimum area allowed for rectangular shapes on a layer, use the oacMinRectArea constraint.
| Constraint type: | oaLayerConstraint |
| Value types: | oaIntValue |
| Database types: | oaDesign, oaTech |
| Object types: | oaAppObject |
The following value types are supported by this constraint:
that represents the minimum area in database units squared
Units: DBU Square
As technologies continue to shrink, a certain minimum width and minimum total area must be maintained in order to keep the metal layer from disappearing completely during the etching process. Previous technologies used special vias that were large enough to maintain the minimum amount of area required to prevent overetching. Now the overlaps are getting so small that the actual area used can be too small to prevent overetching. Using this process rule guarantees a minimum amount of total area required to prevent the etching from completely dissolving the metal layer.
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