Virtuoso XL Layout Editor User Guide

Preparing Your Design for Routing in the Virtuoso XL Layout Editor

Connecting Nets

To create paths that make the required connections between each device in the layout, you can use

■The layout window Create – Path command

The Create – Path command highlights the net you are wiring in both the schematic and the layout.

■Design shapes created by the layout editor: the Create – Rectangle, Create –

Polygon, Create – Pin, and Create – Conics commands, which connect two or more design elements.

Create – Rectangle

Create – Path

Create – Conics – Ellipse

Create – Polygon

■The Virtuoso custom router

For information about using the router, see the Virtuoso Custom Placement and

Routing Preparation Guide.

Creating Paths

To create paths follow these steps.

1.From the layout window, choose Create – Path.

2.In the layout window, click where you want the first point of the path. Virtuoso XL highlights the corresponding net in the schematic and the layout.

Note: You cannot start a path where there is a short.

Virtuoso XL Layout Editor User Guide

Preparing Your Design for Routing in the Virtuoso XL Layout Editor

3. Continue clicking points to draw the path.

Virtuoso XL creates the path using the layer of the shape where you click first. If you click where there is no shape, Virtuoso XL uses the layer selected in the LSW.

The default width of the path is the minWidth layer property defined in thetechnology file.

4.To change the width of the path, press F3 to open the Create Path options form and change the path width on the form.

To erase the segments you draw, press the Back Space key.

If you try to start a path or a shape where there is already a path or a shape on more than one layer, a dialog box appears that shows you what layers are active and asks you to choose one.

5.To complete the path, press Return on the last point.

Note: Do not double-click to end a path. If you have set the layout window Design – Options – Display command to x-first or y-first snap modes, the double-click might make a notch in the path, which triggers an error message and can cause errors in mask layout.

6.To change the current entry layer, choose a different layer in the LSW.

The current entry layer in the LSW is updated. The path you create uses the new layer.

Virtuoso XL Layout Editor User Guide

Preparing Your Design for Routing in the Virtuoso XL Layout Editor

Connecting Nets with Path Stitching

You can draw a path that switches from one layer to another, automatically placing an appropriate contact at the point where the layer changes. This is often called “pathstitching.” To perform path stitching, follow these steps.

1. While the Create – Path command is active, press F3.

Virtuoso XL Layout Editor User Guide

Preparing Your Design for Routing in the Virtuoso XL Layout Editor

The Create Path form appears.

2.To drop a via from the current layer to a new layer and change the current layer, choose a different layer in the Change To Layer cyclic field.

3.Change any other options as required.

4.On the layout window, click where you want the via placed.