A through-hole pad can have different copper geometry on different layers. Looking only at the top layer can miss an undersized internal pad, an unintended shape, or a layer assignment inherited from an earlier stackup. Review the full pad stack for features whose connection depends on those layers.
Altium’s pad and via documentation distinguishes simple, top-middle-bottom, and full-stack definitions. The selected mode controls how layer-specific geometry is represented. A single diameter field does not necessarily describe the complete object.
Identify the geometry model
Record the pad number, hole definition, plating intent, layer-stack mode, and geometry on each applicable copper layer. Keep the hole and copper dimensions distinct. A drill feature and its surrounding copper serve related but different purposes.
Inspect the actual placed pad, not only its source library entry. Local edits or an incomplete library update can make the board instance differ from the library. Use the released board data as the starting point for the manufacturing review. If the library and board differ intentionally, record that approved local exception so a future library refresh does not silently restore the earlier geometry.
Check each layer relationship
| Layer condition | Review |
|---|---|
| Outer mounting layer | Fit and intended solder connection |
| Connected internal layer | Required copper connection and applicable rules |
| Unconnected layer | Clearance from unrelated copper |
| Changed stackup | Correct mapping of existing per-layer geometry |
Compare the intended connection against actual copper after fills are current. A pad may be assigned to the correct net yet have a different physical connection than the reviewer expects. Check the surrounding plane or polygon behavior as well as the pad outline.
Review changes through to fabrication data
- Compare the previous and current pad-stack definitions.
- Check all affected instances in the design.
- Run relevant clearance and connectivity checks.
- Inspect exported layers and drilling together.
- Record supplier questions or accepted construction details.
Do not substitute a generic annular-ring number for the fabricator’s review of the intended construction. The suitable design depends on the hole, plating, registration, connection, and agreed manufacturing requirements. Keep those requirements explicit without assuming that the CAD editor’s default geometry is automatically adequate.
When adding or removing copper layers, revisit full-stack definitions that reference particular layers. A visually unchanged outer pad does not demonstrate that the internal definition survived the edit correctly. Preserve an annotated layer comparison for critical connectors or other repeated through-hole features so that later library changes can be checked against a clear baseline.
Move from reading to a build-ready project
Use the fabrication and assembly checklists to prepare drawings, production files and test requirements.
Open the DFM checklist