Heavy Copper PCB Manufacturing
Heavy Copper PCBs 2oz to 10oz, Built for Power
High-current and thermal management in a single board — power supplies, inverters, EV battery management, and industrial motor drives. IPC-2152 designed, with a 1-piece MOQ.
Copper Weight Range
From 2oz to 10oz — Sized to Your Current
Choosing the right copper weight is the core decision in every heavy copper design. Each additional ounce widens current-carrying capacity and doubles as a heat spreader — so a single board handles the loads found in industrial drives, EV powertrains, and grid-tied inverters.
70μm Copper
Your entry into heavy copper: carries roughly double a 1oz trace, ideal for compact power supplies and moderate-current rails.
105μm Copper
A step up for denser power routing where 2oz runs warm — balances current headroom with achievable trace/space.
140μm Copper
The workhorse for power electronics: 2x the thermal path of 1oz, spreads heat across the board and cuts heatsink demand.
210μm Copper
Top of standard production. Routes 10–50A rails directly through the board and replaces external busbars.
350μm Copper
Custom production with extended lead times for extreme current. Above this, copper coin insertion is the reliable path.
Mixed Stackups
4–6oz power layers paired with 1oz signal layers on one board — power distribution and control logic without a separate board.
Key Advantages
Why Choose Heavy Copper PCBs
Heavy copper turns the board itself into the busbar and the heatsink. Stepping from 2oz to 6oz roughly doubles the current a 20mil trace can carry — from 3.2A to 7.8A — while spreading heat across the copper so a compact power stage runs cooler.
High Current Capacity
2oz copper at 20mil width carries 3.2A. 4oz at 20mil carries 5.5A. 6oz at 20mil carries 7.8A. Eliminate busbars and reduce connector count by routing power directly through the PCB.
Built-In Thermal Management
Heavy copper acts as a heat spreader, conducting heat away from power components. 4oz copper provides 2x the thermal conductivity path of 1oz copper. Reduce or eliminate external heatsinks.
Extreme Reliability
Thicker copper withstands higher thermal cycling stress and provides better mechanical strength at plated through-holes. Rated for -40°C to +150°C continuous operation in power electronics.
Mixed Signal/Power Layers
Combine heavy copper power layers (4-6oz) with standard signal layers (1oz) in one board. Route power and control on the same PCB, eliminating separate power distribution boards.
Heavy Copper Boards We Build
Thick copper, power panels, and the floor that makes them
Design Guidelines
DFM Best Practices for Heavy Copper
Heavy copper design lives and dies on current sizing, thermal management, and copper balance. Here is how we take a power board from trace-width math to a manufacturable, on-target result.
Current Calculation
Follow IPC-2221 standards for trace width sizing. Calculate trace width for your target current with at minimum a 20% safety margin. Always account for ambient temperature — a trace rated for 5A at 25°C may only carry 3.5A at 85°C.
Thermal Relief Design
Use thermal relief pads on power planes to balance thermal dissipation with solderability. Without thermal relief, large copper planes act as heat sinks that make hand soldering impossible and wave soldering unreliable.
Copper Balancing
Maintain equal copper distribution on top and bottom layers to prevent warpage during lamination and reflow. Add copper fills to low-copper layers. For mixed-weight stackups, balance total copper mass symmetrically about the board center.
Trace Width vs Current Tables
Reference IPC-2152 for external and internal layer calculations. Always account for temperature rise — 10°C rise is standard, 20°C for industrial, 30°C maximum. Internal traces carry approximately 50% of external trace current.
Thermal Via Arrays
Dense via arrays under power components conduct heat to inner copper planes and the opposite board side. 0.3mm vias on 1.0mm grid provide approximately 4 W/cm² thermal transfer.
Coin / Slug Insertion
Press-fit copper coins (slugs) embedded in the board provide a direct thermal path from component to heatsink. Thermal resistance below 0.5°C/W for high-power IGBTs and MOSFETs.
Power/Signal Isolation
Maintain minimum 15mil clearance between power traces and signal traces. Use dedicated ground planes between power and signal layers. Creepage and clearance per IPC-2221 for working voltages.
Controlled Etch & Compensation
Thick copper requires controlled etching to manage lateral undercutting. Trace width compensation is applied to your artwork so finished dimensions land on target — 12mil min at 4oz, 15mil min at 6oz.
Technical Specifications
Manufacturing Capabilities & Stackup
Copper weights run 2oz (70μm), 3oz (105μm), 4oz (140μm), 6oz (210μm), and 10oz (350μm) custom, with inner and outer layers independently specified. Current capacity follows IPC-2221: 2oz external carries 1.8A at 10mil, 3.2A at 20mil, 7.0A at 50mil; 4oz external carries 3.1A / 5.5A / 12.0A. Internal traces carry roughly 50% less due to reduced convection.
Minimum trace/space widens with copper weight — 8/8mil at 2oz, 10/10mil at 3oz, 12/12mil at 4oz, 15/15mil at 6oz — to absorb lateral etch undercut. Each ounce adds roughly 35μm per layer, so a 4-layer board at 4oz on all layers adds 0.56mm; a standard 1.6mm board may grow to 2.0mm or 2.4mm.
Thermal and power features go beyond thick traces: thermal via arrays (0.3mm vias on 1.0mm grid, ~4 W/cm²), copper coin insertion (below 0.5°C/W for IGBTs and MOSFETs), edge plating for busbars (2–3x the current of an equal-width surface trace), and HASL / OSP / ENIG finishes — HASL preferred for large power pads, ENIG for mixed signal/power boards with fine-pitch parts.
Applications
Where Heavy Copper PCBs Excel
Heavy copper earns its place wherever sustained high current meets thermal cycling — power conversion, EV electrification, grid infrastructure, and industrial motion.
EV Battery & BMS
Battery management systems, cell balancing, and pack interconnect boards for electric vehicles and energy storage.
Grid & Substation Power
Power distribution boards, busbar replacement PCBs, and switchgear control for industrial and grid-tied power.
EV Powertrain & Drives
On-board chargers, traction inverters, and motor driver boards carrying high-current PWM to power stages.
Industrial Control
Variable frequency drives, servo controllers, and robotic power stages that survive continuous high-current cycling.
The Difference
Why Heavy Copper at AtlasPCB
The hard part of heavy copper isn't laying down thick copper — it's holding trace geometry, copper balance, and thermal paths through an aggressive etch. Our process is built around that.
Up to 6oz Standard
Standard production to 6oz (210μm) with 10oz+ available as custom tooling — no busbars needed for 10–50A rails.
Thermal Engineering
Thermal via arrays, copper coins, and edge plating designed in to shed dissipation from IGBTs and MOSFETs.
Etch Compensation
Specialized etch chemistry and trace width compensation deliver finished dimensions on target despite undercut.
IPC-2221 / 2152 DFM
Every design reviewed for current capacity, copper balance, and creepage before production. No surprises.
FAQ
Common Questions About Heavy Copper PCBs
Standard production supports up to 6oz (210μm) copper. 10oz (350μm) and above is available as custom production with extended lead times. For extreme current requirements above 10oz, consider copper coin insertion as an alternative to full heavy copper layers.
2oz copper adds approximately 20-30% over standard 1oz boards. 4oz adds 60-80%. 6oz can double the cost or more. The primary cost drivers are extra copper material, longer etching cycles, and tighter process control. Mixed copper stackups (heavy power + standard signal) optimize cost.
Yes. Mixed copper weight stackups are common for power electronics. A typical configuration uses 4oz on outer power layers and 1oz on inner signal layers, or vice versa. We verify stackup symmetry to prevent warpage and confirm trace/space minimums for each copper weight.
Thick copper requires controlled etching to manage lateral undercutting. At 4oz, expect 12mil minimum trace/space. At 6oz, expect 15mil minimum. We use specialized etch chemistry and extended process times. Trace width compensation is applied to your artwork to account for undercut and deliver finished dimensions on target.
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