Cadence PCB Best Practices

Working with Backdrilling Backdrilling October 2019 42 Product Version 17.4-2019 © 1999-2020 All Rights Reserved. Tip Once the layers pairs are regenerated backdrill will be out of date. Select the Backdrill button to regenerate backdrill data for pins/vias using the new layer pairs. ■ With the BACKDRILL_LAYER_PAIR_ADJUSTMENT environment variable set, the following message is displayed. Select the OK button to continue. Reviewing the backdrill analysis log, the Remaining Stub Len column reports the distance from the shifted Must Not Cut Layer to the actual connection layer. To Layer Must Not Cut Layer Plunges To Layer Must Not Cut Layer Plunges LAYER_7_P LAYER_6 10 LAYER_7_P LAYER_6 21 LAYER_6 LAYER_5 11

• Cover
• Contents
• Backdrilling
• Introduction
• Licensing
• Prerequisites
• Backdrill Commands, Properties, Parameters, and Subclasses
• Terminology
• Net Identification
• Applying the BACKDRILL_MAX_PTH_STUB Property in Constraint Manager
• Stub Calculation
• Pin Plating Restrictions
• Applying the Minimum Pin Plating Property
• Pressfit Connectors
• Backdrill Exclusions
• User Overrides
• Fabrication Vendor Backdrill requirements (Reference Only)
• Setup and Analysis User Interface
• Initially Launching the Backdrill Setup and Analysis Dialog Box
• Prior to executing Backdrill
• Padstack Parameters Tab of the Backdrill Setup and Analysis Form
• Flag Codes tab of the Backdrill Setup and Analysis form
• Final Backdrill Steps – Executing Backdrill
• Manufacturing Stub Length Analysis (Drill Parameters Tab)
• Effects of Setting a Manufacturing Stub Length:
• Layer Pairs tab feedback – Depth column yellow cells:
• Backdrill Canvas Display Controls
• Backdrill Data Show Element visibility (Pins/Vias)
• DRC and Shape Voiding
• Board Testability
• NC Drill and Legend Output
• Enabling Backdrill Output
• NC Backdrill Legends
• Legend Customization
• Backdrill Cross Section Chart Display