In short
Review HDI and multilayer PCB suppliers by the stackup, microvia route, impedance plan, manufacturing limits and inspection evidence for your design.
Define the stackup before asking who can build it
“HDI capability” is too broad to qualify a supplier. Share the actual layer count, dielectric targets, sequential-lamination structure, microvia locations, via-fill needs, line and space, copper weight, finished thickness and impedance requirements. Ask the fabricator to mark which items fit its routine process and which need engineering review or a different route.
Discuss the via and lamination sequence
A fine-pitch breakout may require laser microvias, stacked or staggered structures, multiple lamination cycles and specific plating controls. These choices affect yield, cost and inspection access. Ask for a proposed build sequence and identify any structures that need reliability testing or design changes. Do not compare supplier capability by a single minimum feature size divorced from the rest of the stackup.
For controlled impedance, agree the calculation inputs, material tolerances, coupon design, target and acceptance window before fabrication. Ask whether the supplier will provide an as-built stackup and measurement results. If a laminate must be substituted, the electrical impact and approval route need to be resolved before release.
Use a first build to confirm repeatability
Request DFM feedback on annular ring, registration, microvia-to-pad, aspect ratio, copper balance and panel handling. For a pilot, identify cross-section, electrical-test, impedance and other records needed for the design. A prototype can demonstrate feasibility, but repeat orders still need material continuity, change control and agreed inspection.
Compare quotations using the same revision, material, lamination sequence, inspection and delivery scope. A lower price is not comparable if it assumes a different stackup or removes evidence that the project needs.
Start with the HDI PCB and multilayer PCB pages, then bring your stackup and fabrication data to a project-specific review.
FAQ
Common questions
What is the first file an HDI PCB supplier needs?+
A controlled stackup and fabrication package showing layers, dielectric targets, via structures, material, copper, finish and any impedance requirements.
Does a minimum line-width claim prove my board is manufacturable?+
No. Feasibility depends on the complete stackup, registration, via and plating route, material and the supplier’s process for the proposed quantity.
What should I request from a pilot build?+
Agree the applicable DFM disposition, as-built stackup, impedance measurements, electrical test and cross-section or reliability evidence for the design.
Technical references
Sources used for this guide
These sources explain the standards, materials or process details discussed above. Check the current revision when applying them to a new design.