HDI can improve usable routing area and shorten interconnects, while increasing process complexity and the need for construction-specific validation.
What to consider
The gain comes from where copper and holes can be placed. Smaller capture lands can create breakout channels and short microvias can remove unused stubs. Neither benefit guarantees a complete high-speed channel or a reliable thermal-cycling result. Cost depends on the actual process, quantity and yield, rather than the HDI label.
A practical review example
An eight-layer conventional design might fit into a smaller HDI outline without reducing its layer count. The appropriate benefit metric is the completed product size and validated performance, not a marketing claim about fewer layers.
Checks before release
- State the size or routing benefit in measurable terms.
- Compare process and inspection burden.
- Use product-level thermal and electrical verification.
Connect this decision to fabrication
Use the stackup planner 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.
- Prove the package escape on a small routing study.
- Compare complete constructions using the same reliability requirements.
- Resolve the fabrication process before locking the layout.
Technical references
HDI construction types and definitionsHDI design and manufacturing overviewReferences checked 2 October 2026. Manufacturer data describes its stated construction and is not an HDIPCB.org manufacturing commitment.