minWireExtension (oacMinWireExtension)

Description

The built-in layer constraint definition oacMinWireExtension specifies the minimum distance a wire must continue past a via cut. The distance is specified in database units.

Wire extensions are specified from the center of the via cut to the inside edge of the wire shape. The contraint definition applies to both cut layers, the one below and the one above.

Constraint at a Glance

Constraint type:	oaLayerConstraint
Value types:	oaIntValue
Database types:	oaDesign, oaTech
Object types:	oaRoute, oaScalarNet, oaBusNetBit, oaAppObject

Values

The following value types are supported by this constraint:

oaIntValue
This value represents the minimum wire extension in database units.

Units: DBU

Parameters

The following parameters are supported by this constraint:

Name	Value Type	Units	Default	Description
coincidentAllowed oacCoincidentAllowedParamType	oaBooleanValue	Boolean	False	When the coincidentAllowed parameter is specified and is true, then shapes can either meet the minimum extension or their edges can be coincident. If the parameter is false or is not specified, then the edges must meet the minimum extension specified and cannot be coincident.
distance oacDistanceConstraintParamType	oaIntValue	DBU	None	If the distance parameter is specified, the constraint is applied only if there are additional neighboring geometries on layer one (the extended layer) that are located within the value given by the distance parameter to the extension beyond the via cut.

Examples

Manufacturing Reasons

Extension rules ensure that the necessary overlaps are maintained to provide good connections after manufacturing. These kinds of constraints are common for metal shapes over cuts. If the process shifts the metal layer, the metal might uncover the cut and the resulting connection would not be clean. Providing the minimum extensions of the metal past the cut ensures that with the process variations and differences, the correct connections are maintained.