minViaExtension

Specifies the minimum extension of a shape on layer1 over a shape on layer2 for the following cases:

The layer1 extension on three sides must be greater than or equal to a given value and the extension on the remaining side must be greater than or equal to a second value.
The extension of two opposite sides must be greater than or equal to a given value, and for the remaining two sides, the extension of one side must be greater than or equal to a second value and the extension of the other side must be greater than or equal to a third value.
A different minimum extension is required for a diagonal edge compared with non-diagonal edges.

minViaExtension Quick Reference

Constraint Type	Layer pair (non-symmetric)
Value Types	`ValueArrayValue`
Database Types	Design, Technology
Scope	design, foundry
Category	Via Construction

Value Type

minViaExtension constraints have a ValueArrayValue that represents the minimum extensions required for the viaExtensionType parameter.

minViaExtension ValueArrayValue by viaExtensionType

viaExtensionType ValueArrayValue

viaExtensionType	ValueArrayValue
`oneThree`	{`Value` `Value`} where the first value is the minimum extension for three sides and the second value is the minimum extension for the fourth side.
`oneOneTwo`	{`Value` `Value` `Value`} where the first value is the minimum extension for two opposite sides, and the second and third values are the minimum extensions for the other two sides.
`diagonal`	{`Value` `Value`} where the first value is the minimum extension for non-diagonal edges and the second is the minimum extension for diagonal edges. {`Value` `Value` `Value`} where the first value is the minimum extension for three sides, the second value is the minimum extension for the fourth side, and the third value is the minimum extension for diagonal edges. {`Value` `Value` `Value` `Value`} where the first value is the minimum extension for two opposite sides, the second and third values are the minimum extensions for the other two non-diagonal sides, and fourth value applies to any diagonal edges.

oneThree

{Value Value} where the first value is the minimum extension for three sides and the second value is the minimum extension for the fourth side.

oneOneTwo

{Value Value Value} where the first value is the minimum extension for two opposite sides, and the second and third values are the minimum extensions for the other two sides.

diagonal

{Value Value} where the first value is the minimum extension for non-diagonal edges and the second is the minimum extension for diagonal edges.

{Value Value Value} where the first value is the minimum extension for three sides, the second value is the minimum extension for the fourth side, and the third value is the minimum extension for diagonal edges.

{Value Value Value Value} where the first value is the minimum extension for two opposite sides, the second and third values are the minimum extensions for the other two non-diagonal sides, and fourth value applies to any diagonal edges.

Parameters

viaExtensionType (StringAsIntValue, required) specifies the type of minimum via extension that the constraint represents, as given in Table .

minViaExtension Types

String	Value	Description
`oneThree`	0	Layer1 extension on three sides must be >= x and the fourth side must be y.
`oneOneTwo`	1	Extension on two opposite sides must be >= x, a third side must be >= y and the fourth side must be >= z.
`diagonal`	2	The layer1 extension to the diagonal edge must be >= w and to the non-diagonal edges >= x.

Examples of minViaExtension Types

Examples

The following example sets the minimum via extension for Metal3 over Via2. Three sides must have a minimum extension of 0.04 and the fourth side has a minimum extension of 0.06.

set_constraint_parameter -name viaExtensionType -StringAsIntValue oneThree
set_layerpair_constraint -group foundry -layer1 Metal3 -layer2 Via2 \
-constraint minViaExtension -hardness hard -ValueArrayValue { 0.04 0.06}

The following example sets the minimum via extension for Metal3 over Via3. Two opposite sides must have a minimum extension of 0.04, and the two remaining sides must have a minimum extension of 0.06 and 0.08.

set_constraint_parameter -name viaExtensionType -StringAsIntValue oneOneTwo
set_layerpair_constraint -group foundry -layer1 Metal3 -layer2 Via3 \
-constraint minViaExtension -hardness hard -ValueArrayValue { 0.04 0.06 0.08}

The following example sets the minimum via extension for Metal4 over Via3. Two opposite sides must have a minimum extension of 0.04, and two remaining non-diagonal sides must have a minimum extension of 0.05 and 0.06. Any diagonal edges must have a minimum extension of 0.07.

set_constraint_parameter -name viaExtensionType -StringAsIntValue diagonal
set_layerpair_constraint -group foundry -layer1 Metal4 -layer2 Via3 \
-constraint minViaExtension -hardness hard -ValueArrayValue { 0.04 0.05 0.06 0.07}

Virtuoso Space-based Router Constraint Reference
Product Version IC23.1, June 2023