Mapping Electroplated Copper Thickness Across a PCB Panel

A single copper-thickness measurement cannot describe every location on a production panel. When investigating variation, build a map that preserves coordinates, feature type and measurement method. An average without that context can hide the region that controls product acceptance.

Define the measurement before collecting values

Atotech’s vPlate description connects its plating-uniformity approach with shielding and jig configuration. Its published equipment results are configuration-specific. Do not adopt them as a guaranteed thickness distribution for a different line or board pattern.

State whether the measurement represents surface copper, a hole-wall location or another specified feature. Record whether the result includes starting foil and which definition the product requirement uses.

Create a reproducible coordinate system

Choose points that represent the actual comparison question. A corner-only survey and a product-feature survey may be useful for different purposes, but they should not be presented as equivalent coverage.

Separate location effects from measurement effects

Repeat selected measurements where the method permits, and use the same definitions across panels. If different laboratories or methods disagree, resolve that comparison before assigning the difference to the plating process.

Keep raw values with the map. A color plot is useful for pattern recognition, but the chosen color scale should not conceal absolute values or change silently between trial runs.

Evaluate a controlled process comparison

1. Record the baseline panel pattern and configuration.
2. Identify the factor being changed.
3. Use the same sampling definitions for both runs.
4. Compare local results against the applicable requirements.
5. Check whether other critical features remain acceptable.

Do not assume an improvement in average surface thickness resolves a concern inside a hole. The selected acceptance feature needs its own evidence.

If the panel layout or loading arrangement changes later, revisit whether the original map still represents production. The study’s value depends on keeping the evaluated configuration connected to the released process.

For example, report the minimum, maximum and their locations alongside any average required by the review. If the acceptance requirement applies to a particular feature, show its individual result. A favorable average should not obscure a local result that falls outside the agreed requirement.

For the data-definition boundary, see base and finished copper requirements. For permitted pattern adjustments, see fabrication copper balancing; a proposed adjustment still needs appropriate product review.