Thermal expansion mismatches can stress microvia interfaces and internal connections. Qualification should represent the manufacturing and service exposures that matter for the product.
What to consider
Define assembly reflow, allowed rework and the expected operating environment before selecting a test plan. Test temperature, cycle count, monitoring and failure criteria must come from the relevant project requirements and agreed standards. A generic cycle count copied from another product does not establish suitability.
A practical review example
When a prototype changes to a thicker production stackup or a different resin system, assess whether existing test data still applies. Record the construction revision with the test report.
Checks before release
- Identify relevant thermal exposures.
- Monitor the appropriate electrical structures.
- Review failures and deviations before release.
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.
- Specify acceptance and thermal exposure before requesting a quotation.
- Match coupon structure and process history to production.
- Review deviations and failure evidence with the responsible engineer.
Technical references
Historical IPC microvia reliability warning (2019)Fabrication design guidelinesReferences checked 2 October 2026. Manufacturer data describes its stated construction and is not an HDIPCB.org manufacturing commitment.