Creating a Shield Constraint

To create a shield constraint and set the associated shielding net:

1. Choose Window – Assistants – Routing.
   Alternatively, right-click anywhere on the layout window menu bar and choose Assistants – Routing.
   The Routing assistant is displayed.
2. Click Routing Constraint Manager on the Routing assistant toolbar.
3. Select the net on which you want to add the shield constraint from the Net column in the Nets tab.
   If you select multiple nets and apply a shielding constraint, a consistency check warning message is displayed in the CIW.
   
   
4. Click Apply Shield Constraint Group on the Routing Constraint Manager toolbar. Alternatively, right-click and choose Add to Constraint – Shield Constraint Group – <ShieldCGname>.
   You can also right-click and choose Create Constraint…– Shield Constraint Group. This lets you to either use the existing shield constraint group or create a new one.
   The shield constraint is added to the selected nets. You can now adjust the shield nets.
   
   Before shielding is created, ensure that geometric power mesh shapes exist. Therefore, use supply routing before routing with shields or manually create trunks on power ground nets.
5. To adjust shield nets, double-click the shield constraint group on a net.
   The Edit Occurrence form appears. You can either edit the shield constraint group for all occurrences or for selected occurrence.
   
   
   
6. Ensure that All Occurrences is selected. This is the default option. Selecting All Occurrences affects all constraints that are using this shield constraint.
7. Click OK.
   The Shield Process Rule Override Editor form appears.
   
   
8. Expand Shield Width/Space and the Advanced Shield sections to view the options.
9. Change the minimum width and minimum spacing to 0.1um for the metal layers.
10. Click OK.
    You have defined the shield constraint on the selected nets and adjusted the shield nets.

Related Topics

Loading Routing Constraints

Creating and Deleting a Constraint Group

Editing a Constraint

Selecting Nets in Navigator

Setting up a Constraint on a Net

Adding and Removing a Net from a Constraint Group

Shield Process Rule Override Editor Form