Antenna Generation for MUSTJOIN and MUSTJOINALLPORTS Terminals

Abstract Generator computes the antenna data for a given layer. The antenna parameters for some of these layers are defined in the LEF technology file. The main antenna calculation is performed at the end of the Extract step, where Abstract Generator computes antenna data.

During antenna calculation when extraction is performed using the Extract step, a single island of overlapping or connected shapes is created for each terminal. In this island, all shapes are connected as per the layer connectivity model. Antenna numbers are calculated according to shapes in the island, which depends on their connectivity to other shapes.

If some preexisting constraints are preventing all the shapes to be connected, you can use either the MUSTJOIN setting or the MUSTJOINALLPORTS property to connect all the shapes from outside. These settings let the router connect all the shapes from outside when no space is available for the metal shapes inside the cellview.

Virtuoso Abstract Generator User Guide
Product Version IC23.1, November 2023