Sequential lamination adds layers in stages so internal interconnects can be formed before later copper and dielectric cover them.
What to consider
Count the actual pressing operations, including core subassemblies where applicable. The two sides of a symmetric build-up can be processed together, so 2+N+2 does not automatically mean four separate outer presses. The count changes if the core needs additional sublaminations or the factory uses another qualified process.
A practical review example
In the tool’s simplified example, a multilayer core with one initial press and two symmetric build-ups yields three press steps. A purchased two-sided core changes the starting assumption. Ask the factory to confirm the real count.
Checks before release
- Separate copper-layer count from pressing operations.
- Review cumulative thermal exposure.
- Use the factory-approved process for cost and lead-time estimates.
Connect this decision to fabrication
Use the lamination guide 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.
- Ask the fabricator to confirm the complete construction in writing.
- Resolve manufacturing exceptions before tooling.
- Retain the approved drawing, stackup and inspection plan with the release.
Technical references
Fabrication design guidelinesConstruction-specific HDI capabilities and FAQReferences checked 2 October 2026. Manufacturer data describes its stated construction and is not an HDIPCB.org manufacturing commitment.