Define the electrical and mechanical requirements
Record board dimensions, interfaces, critical electrical behavior and environmental needs. Discuss stack-up, controlled impedance and relevant material properties with the fabricator and design team. A familiar material name alone may not adequately define performance for a demanding application.
Connect package choice to assembly and inspection
Fine-pitch and bottom-terminated packages can introduce placement, soldering, inspection and rework challenges. Consider test coverage and access alongside the footprint. Review the manufacturer’s capability for the actual geometry and process rather than relying on a broad package-size claim.
Evaluate complexity against demonstrated need
Blind or buried vias, via-in-pad structures, rigid-flex construction and unusual materials may solve real design constraints, but they also change fabrication and assembly considerations. Document why the technology is needed and which alternatives were evaluated. Avoid adding complexity without a corresponding product benefit.
Release a complete fabrication specification
Communicate the agreed stack-up, material requirements, surface finish, tolerances and special notes in the fabrication package. Keep the specification aligned with assembly, test and mechanical requirements. Resolve engineering questions before allowing a supplier to make an assumption that changes the design intent.
At a glance
| CHOICE | INFLUENCES | REVIEW WITH |
|---|---|---|
| Stack-up and material | Signal, thermal and mechanical behavior | Design team and fabricator |
| Surface finish | Assembly compatibility and handling | Fabricator and assembler |
| Interconnect structure | Routing, fabrication and reliability | Design and manufacturing engineering |
| Component package | Placement, joints, inspection and rework | Assembly and test engineering |
A practical checklist
- State the performance requirement first.
- Agree stack-up and material specifications.
- Review package and inspection compatibility.
- Document special fabrication requirements.
- Align mechanical, fabrication and assembly files.
- Approve changes before material commitment.
Assign an owner to each open item and keep the decision with the project revision. A checked box should point to a document, approval or piece of evidence; it should not simply indicate that a topic was discussed.
A common mistake to avoid
Allowing an “equivalent” material or surface finish without reviewing the relevant properties and process effects. Equivalence should be defined by the product requirements and approved by the responsible engineering team.
Put the guidance to work
Start with the RFQ preparation checklist, keep component information in the BOM template, and compare evidence using the supplier scorecard. Confirm project-specific requirements with your design team and manufacturing partner.
Explore the related manufacturing scope or return to the PCB Technology guide hub.