Cadence PCB Best Practices

Working with Backdrilling Backdrilling October 2019 16 Product Version 17.4-2019 © 1999-2020 All Rights Reserved. Figure 1-6 Must Not Cut Layer surface inside minimum pin plating depth Automatic layer pair shift allows backdrill outside min pin plating depth. Tip The backdrill code stops the backdrill at the layer before the Must Not Cut Layer (Connection Layer) called the To Layer preserving the adjacent dielectric layer. Fabrication vendor could backdrill further into the adjacent dielectric layer to remove as much electrical stub as possible, without compromising the Must Not Cut Layer.

• 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