A successful HDI layout starts with package escape, layer allocation and factory-approved interconnects. Detailed routing follows those decisions.
What to consider
Build a representative escape for the hardest package. Allocate ground and power copper, identify the signal layers that can actually be reached, and ask the fabricator to propose pressed materials and via geometries. Encode those values as design rules. Review the full route and return path before adding fine length tuning.
A practical review example
At the pre-layout review, bring the package pin map, initial placement, thickness limit, interfaces and quantity. At release, provide artwork, drills, stackup, impedance requirements, dimensions and a consistent revision. Separate unresolved questions from approved requirements.
Checks before release
- Resolve the construction before dense routing.
- Use specific constraints by region and net class.
- Run a final drill-span and fabrication-note reconciliation.
Connect this decision to fabrication
Use the design checklist to organize the initial discussion. Keep proposed values separate from the approved drawing and document the effect of any change on the rest of the construction.
- Use rules confirmed for the chosen factory and construction.
- Inspect return paths through every critical breakout.
- Release consistent artwork, drills, stackup and drawing revisions.
Technical references
HDI design and manufacturing overviewFabrication design guidelinesReferences checked 2 October 2026. Manufacturer data describes its stated construction and is not an HDIPCB.org manufacturing commitment.