Define qualification before requesting credentials

List the critical characteristics of the design: via arrangement, materials, tolerances, surface requirements and expected assembly exposure. Identify which are routine for the supplier and which require development or additional review. This focuses the discussion on the actual manufacturing risk.

ISO's supply chain guidance treats quality management information as a tool in supplier selection. Verify the scope and identity of any claimed certification, then assess how the supplier's controls apply to this job. Do not infer a particular HDI capability from a general management system certificate.

Ask for evidence with a relevant comparison

Request examples or test summaries that can be shared without exposing another customer's confidential design. Ask how their geometry, material system and process history compare with your construction. A relevant anonymized example can be more useful than a glossy photograph of an unrelated advanced board.

Review who owns fabrication engineering, which operations occur at the proposed site and how external processes are controlled. Record the scope being evaluated so a later site or subcontractor change is visible.

Examine the response to problems

Discuss how deviations are requested, nonconforming results are contained and corrective actions are verified. Ask what records accompany delivery and how they connect to lot identity. These practical controls determine whether your team can make a timely decision when an unexpected result appears.

  • Compare the proposed construction with demonstrated experience.
  • Confirm site, process and external operation responsibilities.
  • Agree on reports, sampling and traceability requirements.
  • Define notification and approval rules for meaningful changes.

Keep approval proportional and current

A supplier may be suitable for one construction and unproven for another. Record the approved scope and any conditions, such as an additional first build review. Avoid a single permanent approved label that hides the difference between established and newly introduced technology.

Revisit the assessment when the project, manufacturing site or construction changes materially. Use delivery and technical performance records to improve the evaluation, while distinguishing communication problems, design ambiguity and actual manufacturing failures.

DESIGN NOTE / SCHEMATIC

Adjacent-layer access, one connection at a time

Signal copper

Dielectric · geometry + material

Reference copper

Core or build-up dielectric

Signal copper

Illustrative only. Copper thickness, dielectric construction and via spans require a reviewed stackup.

Common questions

Does a quality certificate prove an HDI process is qualified?

No. Verify its scope, then examine construction specific process and test evidence. Management system certification and a particular board's performance are different questions.

Must a supplier reveal other customers' designs?

No. Ask for permitted anonymized evidence, relevant test summaries or an agreed evaluation build. Protect confidentiality while still requesting a meaningful technical comparison.

References & further reading

Method & assumptions · General design guidance. Validate the proposed construction and acceptance criteria for your project.