Make the process visible in the drawing

A finished cross-section should identify every copper layer and dielectric region, but it also needs a companion table showing how vias connect those layers. Indicate which structures are created before later layers conceal them. This makes an impossible or ambiguous connection easier to detect before tooling starts.

Altium's via documentation distinguishes layer-span definitions from dimensional properties. Apply the same separation to your release: the span tells the fabricator where the feature belongs; its dimensions and construction notes explain what must be produced.

Review the constraints as a coupled set

Do not approve a minimum track width, a minimum via diameter, and a thin dielectric independently and assume the combination is qualified. Copper thickness affects the fine-line process; dielectric construction affects drilling; landing geometry affects registration margin. The selected combination is the manufacturing requirement.

Ask reviewers to mark concerns on the actual dense region. A generic capability sheet is less useful than an agreed pad, via, and trace arrangement tied to the proposed stack.

Plan checks where they answer a question

An inspection step should identify the failure it is intended to reveal. Image inspection evaluates patterned conductors; dimensional review checks geometry; electrical testing checks connectivity under specified conditions. Structural and thermal evaluations address different questions. Combining their names in a purchase note does not define coverage.

  • Identify representative difficult structures for inspection or coupons.
  • Assign acceptance requirements and revision references explicitly.
  • State which results accompany the first article and repeat lots.
  • Resolve deviations before treating them as an accepted baseline.

Freeze a coherent production record

For an illustrative first build, retain the approved stack, manufacturing questions, final artwork, drill files, netlist, and test requirements together. If a dielectric or pad changes during review, update the electrical model and source CAD as necessary. Otherwise, the next order can silently revert to the earlier design assumption.

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

Are Gerber files alone sufficient?

They describe artwork, but do not necessarily resolve stack materials, via construction, impedance, acceptance, or assembly exposure. Supply the missing requirements explicitly.

Can a supplier choose equivalent materials?

Only within a defined substitution policy. Evaluate electrical, thermal, dimensional, and processing consequences before approving a proposed alternative.

References & further reading

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