What is the heaviest copper you can build?

12 oz on inner layers and 14 oz on outer layers.

Can heavy copper and fine signal traces share one board?

Yes. Mixed copper weights within a single stack-up are a standard build; the signal layers keep normal design rules while power layers carry the current.

Do heavy copper boards need a different surface finish?

Not necessarily, but HASL and ENIG are the usual choices because they tolerate the higher thermal mass during assembly.

— CAPABILITIES

Heavy Copper PCB Capability

HyperPCB manufactures heavy copper PCBs with inner layers up to 12 oz and outer layers up to 14 oz, for power conversion, busbar replacement and thermal spreading — including mixed-weight builds that carry current and signals on one board.

— SPECIFICATIONS

Capability & tolerance chart

Heavy Copper PCB Capability — standard vs advanced.
Parameter	Standard	Advanced
PCB Types	Heavy copper, thick copper, high-current, power and heavy copper multilayer boards	—
Layer Count	Up to 20 layers	—
Maximum Inner Layer Copper	Up to 12 oz	—
Maximum Outer Layer Copper	Up to 14 oz	—
Finished Board Thickness	Up to 236 mil	Thicker designs by project review
Through-Hole Aspect Ratio	Up to 14:1 on heavy copper structures	—
Mechanical Blind Via Aspect Ratio	Up to 1.2:1	—
Line Width / Spacing at 4 oz	9.84 / 9.84 mil	—
Line Width / Spacing at 6 oz	17.7 / 17.7 mil	—
Line Width / Spacing at 10 oz	23.6 / 23.6 mil inner layers	25.6 / 25.6 mil outer layers
Voltage Withstand	Up to 6000 VDC by project design and validation	—
Lamination Cycles	Multiple lamination cycles supported	—
Materials	FR-4, High Tg FR-4, halogen-free FR-4, high thermal conductivity, metal-core and heavy copper laminates	—
Special Processes	Heavy copper etching, high-current plating, resin-plugged vias, controlled-depth routing, embedded copper, edge plating	—

Etching thick copper is a different process

At 6 oz and above, sidewalls slope and fine features disappear. Line width and spacing rules therefore scale with copper weight, and we will tell you the achievable geometry for your weight rather than accepting artwork that cannot be etched. Where a design needs both, mixed-weight construction keeps signal layers fine and power layers thick.

Current, temperature rise and via design

Copper cross-section, allowable temperature rise and ambient conditions decide the build. Send the current per net and the maximum rise you can accept; we return a copper weight, trace geometry and via arrangement that meets it, plus the plating specification for high-current barrels.

— FAQ