minExtensionEdge

Specifies the minimum extension of shapes on layer1 past shapes on layer2. Typically, layer1 is a metal layer and layer2 is a cut layer. The specified extension is typically larger than minExtension and minDualExtension values. The larger minExtensionEdge value is required only if the following conditions are met:

• The extension is only required if the metal enclosing the cut has width >= width, a parallel metal edge that is less than parallelEdgeWithin user units away with a parallel run length > parallelEdgeLength.
• The extension may be required only for cut shapes of particular cut classes, identified by their via width and height/length.
• For some processes, the rule does not apply if there is an extra cut and may require the extra cut to be less than or equal to oaDistanceWithin user units away.
• For some processes, the rule does not apply if there are two edges on either side of the metal shape that have parallel run length > parallelEdgeLength and within parallelEdgeWithin, parallel to the enclosing metal edge.

minExtensionEdge Quick Reference

Constraint Type	Layer pair
Value Types	Value
Database Types	Design, Technology
Scope	design, foundry
Category	Extension
Group Operators	AND, OR

Value Type

Value

Represents the overhang of layer1 past layer2, in user units.

Required Parameters

None

Optional Parameters

cutClass	Specifies that the constraint applies only to a cut class of the given dimensions. Type: DualValue
twoSides	Specifies that if the overhang on the layer above the cut layer of a via cut is less than or equal to the value of the constraint, the entire opposite edge must also have overhang less than or equal to the constraint value. Cannot be specified with width or minSpanLength. Type: BoolValue
endOfLineWidth	Specifies that if this parameter is set and both overhangs are less than or equal to the value of the constraint, the overhang edges cannot be end-of-line edges with a length less than this parameter value. Applies only if twoSides is true. Type: Value
exceptConcaveCornerWithin
	Specifies that if this parameter is set and both overhangs are less than or equal to the value of the constraint, there must not be a concave corner on the above metal layer within this distance of the opposite overhang edges. Applies only if twoSides is true. Type: Value
cutToMetalSpacing	Specifies that if this parameter is set and both overhangs are less than or equal to the value of the constraint, the distance between the cut edge to a different net wire on the above metal layer must be greater than or equal to this value. Applies only if twoSides is true. Type: Value
width	Specifies that the constraint applies only if any edge of the cut layer is enclosed by metal that is greater than or equal to this width (minWidth). Cannot be specified with twoSides or minSpanLength. Type: Value
parallelEdgeWidth	Specifies that the constraint applies only if the parallel neighbor metal is greater than or equal to this value in width (parWidth). Can only be used with width. Type: Value
maxWidth	Specifies that the width of the wire containing the via cut must be greater than or equal to width and less than this maxWidth value, and all the corresponding enclosure edge rules that meet the parallel and within conditions are applied to the cut. If any one of the minExtensionEdge constraints for a given set of layers specify maxWidth, then all of them must have maxWidth. Can only be used with width. Type: Value
minSpanLength	Specifies that the width of the wire does not affect whether the constraint applies; instead, the enclosure edge rule applies if the span length of the wire containing the cut via in the direction perpendicular to the parallel run length is greater than or equal to this value. Cannot be specified with the width or twoSides parameter. Type: Value
maxSpanLength	Specifies that the enclosure rule applies if the span length of the wire containing the cut via in the direction perpendicular to the parallel run length is greater than or equal to minSpanLength and less than this value. If any one of the minExtensionEdge constraints for a given set of layers specifies maxSpanLength, then all of them must have maxSpanLength. Can only be used with minSpanLength. Type: Value
parallelEdgeLength	Specifies that the constraint applies when the parallel edge length (parLength) of the enclosing metal edge to another metal edge is greater than this value. Required except if twoSides is specified. Cannot be used with twoSides. Type: Value
parallelEdgeWithin	Specifies that the constraint applies when the distance (parWithin) between a parallel metal edge and the enclosing metal edge is less than this value. Required except if twoSides is specified. Cannot be used with twoSides. Type: Value
parallelEdgeMinWithin
	Specifies that the constraint applies only if the parallel neighbor metal edge is greater than or equal to this distance away. Applies only with parallelEdgeWithin. Type: Value
exceptExtraCut	Specifies that the constraint does not apply when there is another via cut in the same metal intersection, if set to true. Cannot be used with twoSides. Type: BoolValue
oaDistanceWithin	Specifies that the constraint does not apply if exceptExtraCut is set to true and there is another via cut less than this distance from the first via cut (extraCutWithin). Applies only with exceptExtraCut. Type: Value
exceptTwoEdges	Specifies that the constraint does not apply if the enclosing metal edges have parallel metal edges longer than parallelEdgeLength that are less than parallelEdgeWithin away on opposite sides. Cannot be used with twoSides. Type: BoolValue
exceptWithin	Specifies that the exceptTwoEdges parameter applies only if the edges on opposite sides are greater than this value away. Applies only when exceptTwoEdges is true. Type: Value
includeCorner	Specifies that the constraint applies to the corner of the cut, using Euclidian measurement. Cannot be used with twoSides. Type: BoolValue

Examples

Example 1: minExtensionEdge

set_layerpair_constraint -constraint minDualExtension \
  -layer1 Metal1 -layer2 V1 -DualValue ( 0.0 0.05)

set_constraint_parameter -name width -Value 0.2
set_constraint_parameter -name parallelEdgeLength -Value 0.25
set_constraint_parameter -name parallelEdgeWithin -Value 0.11
set_layerpair_constraint -constraint minExtensionEdge \
  -layer1 Metal1 -layer2 V1 -Value 0.05

Requires an extension of 0.02 user units only if both of the following conditions are true:

• The V1 via is enclosed by Metal1 greater than or equal to 0.2 in width.
• There is a Metal1 edge less than 0.11 user units away from the enclosing metal with a parallel run length greater than 0.25 user units.
  
  

Example 2: minExtensionEdge with exceptTwoEdges

set_constraint_parameter -name width -Value 0.2
set_constraint_parameter -name parallelEdgeLength -Value 0.5
set_constraint_parameter -name parallelEdgeMinWithin -Value 0.08
set_constraint_parameter -name parallelEdgeWithin -Value 0.10
set_constraint_parameter -name exceptTwoEdges -BoolValue true
set_constraint_parameter -name exceptWithin -Value 0.12
set_layerpair_constraint -constraint minExtensionEdge \
  -layer1 Metal1 -layer2 V1 -Value 0.05

Requires an extension of 0.05 user units only if the V1 via is enclosed by Metal1 metal greater than or equal to 0.2 in width and there is a Metal1 edge greater than or equal to 0.08 and less than 0.11 user units away with a parallel run length greater than 0.5 user units, except when the enclosing metal edges have parallel metal edges longer than 0.5 that are greater than 0.12 away on opposite sides.

Example 3: minExtensionEdge with parallelEdgeWidth and includeCorner

set_constraint_parameter -name width -Value 0.2
set_constraint_parameter -name parallelEdgeLength -Value 0.5
set_constraint_parameter -name parallelEdgeWithin -Value 0.10
set_constraint_parameter -name parallelEdgeWidth  -Value 0.2
set_constraint_parameter -name includeCorner -BoolValue true
set_layerpair_constraint -constraint minExtensionEdge \
  -layer1 Metal1 -layer2 V1 -Value 0.05

Requires an extension of 0.05 user units, including corners, only if the V2 via is enclosed by Metal2 metal greater than or equal to 0.2 in width and there is a Metal2 edge less than 0.1 user units away with a parallel run length greater than 0.5 user units and the parallel neighbor metal is greater than or equal to 0.2 in width.

Example 4: minExtensionEdge with twoSides and endOfLineWidth

set_constraint_parameter -name endOfLineWidth -Value 0.15
set_constraint_parameter -name twoSides -BoolValue true
set_layerpair_constraint -constraint minExtensionEdge \
  -layer1 Metal1 -layer2 V1 -Value 0.02

Specifies that if an overhang on the layer above the cut layer of a via is less than 0.02 user units, then the entire opposite edge must also have an overhang less than or equal to 0.02, and the overhang edges cannot be end-of-line edges less than 0.15 user units in length.

Example 5: minExtensionEdge with twoSides, exceptConcaveCornerWithin and cutToMetalSpacing

set_constraint_parameter -name exceptConcaveCornerWithin -Value 0.05
set_constraint_parameter -name twoSides -BoolValue true
set_constraint_parameter -name cutToMetalSpacing -Value 0.07
set_layerpair_constraint -constraint minExtensionEdge \
  -layer1 Metal1 -layer2 V1 -Value 0.02

Specifies that if an overhang on Metal1 shape past a cut on V1 is less than 0.02 user units, then the entire opposite edge must also have an overhang less than or equal to 0.02. Additionally, there must not be a concave corner on Metal1 within 0.05 user units of those overhangs, and the spacing of a cut edge fulfilling the overhang requirement to a different net wire on Metal2 must be at least 0.07.

Example 6: minExtensionEdge with minSpanLength, parallelEdgeLength, and parallelEdgeWithin

set_constraint_parameter -name minSpanLength -Value 0.2
set_constraint_parameter -name parallelEdgeLength -Value 0.1
set_constraint_parameter -name parallelEdgeWithin -Value 0.09
set_layerpair_constraint -constraint minExtensionEdge \
  -layer1 Metal1 -layer2 V1 -Value 0.02

Specifies that the minimum enclosure edge depends on the span length of the Metal1 wire containing the V0 cut shape in the direction perpendicular to the parallel run length.

Related Topics

Extension Constraints

check_extension

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