Product Documentation
Virtuoso Space-based Router Command Reference
Product Version IC23.1, September 2023

Routing Vias

Vias that can be used by the router must be specified in the validRoutingVias or extendedValidRoutingVias constraint. The validRoutingVias are typically defined in the design database. The extendedValidRoutingVias constraint can only be set by running the create_derived_vias command and can include the validRoutingVias. If extendedValidRoutingVias exists, it is used for the list of valid routing vias, otherwise, validRoutingVias is used.

Types of Valid Routing Vias

The following table describes the types of valid routing vias that can be used in a design.
Via Type Description

standard vias

(Defined in the viaDefs section of the technology file). Typically, this is a set of standard vias between the poly layer and the highest metal layer. Standard vias are defined by a fixed set of parameters.

custom vias

(Defined in the viaDefs section of the technology file). Custom vias are based on cellviews that must exist in the design library.

via variants

(Can be defined in the viaDefs section of the technology file, or created using the create_via_variant command). These include variants of both standard and custom vias.

derived vias

(Created using the create_derived_vias command). Derived vias are design rule compliant for the standard vias specified in the validRoutingVias list for each route spec that is used in the cellview. You can specify the number and type of derived vias that are created based on available constraints and command settings.

Getting Via Information

To get specific information on a routing via, including cut layer and metal layer names, the number of cuts, columns, and rows, and preferred extension directions, use get_route_via_info. The information can be used to sort vias based on user-defined cost functions.

Related Topics

Preparing the Routing Environment

Determining Which Via the Router Will Use

Using Via Abstraction

Controlling Via Stacking


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