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Virtuoso XL Layout Editor User Guide

10

Preparing Your Design for Routing in the Virtuoso XL Layout Editor

This chapter explains how the Virtuoso® XL layout editor (Virtuoso XL) processes connectivity information and presents several ways to prepare your design for routing. This chapter discusses the following topics:

Understanding Connectivity on page 344

Selecting Layers on page 346

Connecting Nets on page 348

Checking Connectivity with Flight Lines on page 353

Checking Connectivity with Markers on page 353

Defining Physical Vias on page 356

Using the Virtuoso Compactor on a Routed Design on page 361

For information about how to use the Virtuoso custom router to route your design, see the

Virtuoso Custom Placement and Routing Preparation Guide.

For information about running the router, see the Online Help (available in PDF format in your router installation hierarchy).

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Virtuoso XL Layout Editor User Guide

Preparing Your Design for Routing in the Virtuoso XL Layout Editor

Understanding Connectivity

Virtuoso XL accepts only connections

On layers that have been defined in thetechnology file as lxExtractLayers (and on no other layers)

Between two touching shapes or instance pins on the same layers

Between two touching shapes or instance pins on different layers if the layers have been defined in the technology file as equivalentLayers or one of them is defined as a viaLayer

Between two layers by means of a contact instance having a pin on each layer and both pins on the same terminal

M1_M2

metal1

via with pin on metal1 and pin on metal2 on same terminal

metal2

In the technology file:

metal1 and metal2 are lxExtractLayers

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Preparing Your Design for Routing in the Virtuoso XL Layout Editor

Between two layers by means of a via

metal1

via layer

metal2

In the technology file:

metal1 and metal2 are lxExtractLayers via layer is set to viaLayers

Note: By default, Virtuoso XL uses symbolic vias defined in the technology file. You can also definephysical vias using the Virtuoso layout editor if you need shapes not supported by the symbolic via.

When a connection occurs between wires inside an instance, the connectivity extractor checks connectivity for as many levels of hierarchy as specified in theLayout XL Options form.

Cell boundary

Valid connection

Pin A

 

Valid connection

if wires are on the same net and extraction level is set

to greater than 0.

If the wire touches an internal net not

connected to any instance pin, it creates a short

and generates a marker.

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