Routing Via Style

Rule category: Routing

Rule classification: Unary

Summary

This rule specifies the routing via diameter and hole size.

Constraints

Default constraints for the Routing Via Style rule.

• Via Diameter– specifies constraint range values to be adhered to with respect to the diameters of vias placed when routing the board. The following individual values are definable:
  • Minimum – the minimum permissible value for the via diameter.
  • Maximum – the maximum permissible value for the via diameter.
  • Preferred – the preferred value for the via diameter.
• Via Hole Size– specifies constraint range values to be adhered to with respect to the hole sizes of vias placed when routing the board. The following individual values are definable:
  • Minimum – the minimum permissible value for the via hole size.
  • Maximum – the maximum permissible value for the via hole size.
  • Preferred – the preferred value for the via hole size.

How Duplicate Rule Contentions are Resolved

All rules are resolved by the priority setting. The system goes through the rules from highest to lowest priority and picks the first one whose scope expression matches the object(s) being checked.

Rule Application

The Preferred via attributes are used by the Autorouter.

The Minimum and Maximum via attributes are obeyed by the Online DRC and Batch DRC. They also determine the range of permissible values that can be used during interactive routing, when you press the * shortcut key to toggle routing signal layers, or when you press the / shortcut key to connect to a plane layer. Press the Tab key while routing to change a value within its defined range. If a value is entered outside of its range, a dialog will appear alerting you to this fact. You will be prompted to either continue, in which case the value will automatically be clipped, or cancel and change the value yourself.

Notes

In order to control the size of blind and buried vias, individual rules can be set up targeting the different layer pairs. For example, to control the via size for blind vias between the top layer and mid layer 1, the following scope (Full Query) can be used:

(StartLayer = 'Top Layer') and (StopLayer = 'Mid-Layer1')

To control the via size for buried vias between mid layer 2 and mid layer 3, the following scope would be used:

(StartLayer = 'Mid-Layer2') and (StopLayer = 'Mid-Layer3')

Alternatively, instead of creating individual rules, you can expand the one rule query using ORs as follows:

((StartLayer = 'Top Layer') and (StopLayer = 'Mid-Layer1')) or((StartLayer = ' Mid-Layer2') and (StopLayer = 'Mid-Layer3'))