Via Header Functions

Via header objects hold information that is common to all vias referring to a specific viaDef. Via header objects reside in cellviews and are created and automatically managed by the database system. Users can only access via headers and their attributes but are not allowed to change them. Based on the two types of via definitions available in the technology database, there are two types of via headers: standard viaHeaders and custom viaHeaders. Standard viaHeaders contain information common to all standard vias in a route that refer to a specific standard via definition. Custom viaHeaders contain information common to all custom vias in a route that refer to a specific custom via definition in the technology database.

If the master cellview associated with a viaDef is custom parameterized, custom viaHeaders are further classified as via superHeaders or via subHeaders. Via superHeaders represent all of the instances of a Pcell master, regardless of parameter settings. Via subHeaders represent all of the instances that have one specific set of parameter values. Every custom via of a Pcell has one subHeader, which, in turn, has one superHeader. CustomViaHeaders for instances that are not Pcells are neither via subHeaders nor via superHeaders. Standard viaHeaders always have a fixed set of parameters associated with them and thus always fall into either the superHeader or subHeader category.

This topic provides a list of Cadence® SKILL functions related to via header.

Only the functions listed here are supported for public use. All other functions, regardless of their name or prefix, and undocumented aspects of the functions described below, are private and are subject to change at any time.

Related Topics

dbFindViaHeaderByName