High Current and Thick Copper PCBs for Power Electronics Applications
Aspocomp manufactures heavy copper PCBs (thick copper PCBs) designed for applications requiring high current capacity, efficient heat dissipation and long-term reliability.
With capability up to 6 oz (210 µm) copper on inner layers and 8 oz (280 µm) on outer layers, our boards support demanding power electronics applications in automotive, industrial and defense sectors.
What is a heavy copper PCB?
A heavy copper PCB is a printed circuit board that uses significantly thicker copper layers than standard PCBs.
While standard boards typically use 1–2 oz copper (35–70 µm), heavy copper PCBs are generally defined as boards with 3 oz (105 µm) or more copper thickness.
This increased copper thickness enables:
- Higher current-carrying capacity
- Lower electrical resistance
- Improved heat dissipation
- Greater mechanical strength
Heavy copper PCBs are widely used in power electronics, where current levels and thermal loads exceed the limits of standard PCB designs.
Typical use cases for heavy copper PCBs
Heavy copper PCBs are essential in applications with high current and thermal demands.
Industrial power electronics
Motor drives, welding equipment and high-current control systems.
Defense & aerospace
Radar power systems, ruggedized converters and mission-critical electronics.
Renewable energy systems
Solar inverters and wind turbine power control systems.
Key benefits of heavy copper PCBs
| Benefit | Description |
| High current capacity | Thick copper traces can carry high currents (tens to hundreds of amps) with minimal temperature rise. |
| Improved thermal performance | Copper acts as a built-in heat spreader, reducing hotspots and improving heat dissipation. |
| Mechanical strength | Thick copper enhances structural integrity and resistance to thermal cycling. |
| Compact power design | Enables integration of power and control circuits on a single PCB. |
| Reduced resistance | Lower conductor resistance improves efficiency in high-power circuits. |
Technical capabilities – Heavy copper PCB manufacturing
| Feature | Specification |
| PCB Type | Heavy copper PCB, thick copper PCB |
| Inner Layer Copper | Up to 210 µm (6 oz) |
| Outer Layer Copper | Up to 280 µm (8 oz) |
| Layer Count | Up to 40+ layers |
| Board Thickness | 0.3 – 6.0 mm |
| Aspect Ratio | High aspect ratio capability |
| Surface Finishes | ENIG, ImAg, ImSn, ENEPIG, HASL |
| Materials | Standard FR-4, high-Tg, hybrid constructions |
| Certifications | ISO9001, ISO14001, AS9100 |
Aspocomp supports design optimization for heavy copper PCB layouts, including trace width, spacing and thermal performance.
Heavy copper PCB manufacturing process
Manufacturing thick copper PCBs requires specialized process control.
- Engineering and DFM review
Design rules are adapted for thick copper, including trace width and spacing. - Imaging and etching
Specialized etching processes control undercutting and maintain trace geometry. - Advanced lamination
High-flow prepregs are used to fill gaps between thick copper features. - Copper plating
Through-hole plating ensures reliable interconnections under thermal stress. - Final inspection and testing
Cross-section analysis verifies copper thickness and structural integrity.
Heavy copper PCB challenges – and how we solve them
| Challenge | Aspocomp solution |
| Trace undercutting during etching | Optimized etching chemistry and process control |
| Resin voids between thick copper features | High-flow prepregs and controlled lamination cycles |
| Solder mask thinning | Specialized coating techniques for uniform coverage |
| Thermal stress on vias | Robust plating processes for high reliability |
| Design complexity | Engineering support through NPI team |
When do you need a heavy copper PCB?
Heavy copper PCB is ideal when:
- High current (>10–20 A per trace) must be carried
- Power electronics require efficient heat dissipation
- Thermal cycling conditions are demanding
- Mechanical robustness is critical
Standard PCB may be sufficient when:
- Current levels are low
- Fine-pitch routing is required (<100 µm)
- Thermal loads are moderate
Heavy copper PCB vs standard PCB
| Feature | Heavy copper PCB | Standard PCB |
| Copper thickness | 3–8 oz (105-280 µm) | 1–2 oz (35-70 µm) |
| Current capacity | Very high | Limited |
| Thermal performance | Excellent | Moderate |
| Mechanical strength | High | Standard |
| Trace resolution | Lower (wider traces required) | High (fine pitch possible) |
| Applications | Power electronics, EV systems | General electronics |
Frequently asked questions
What is a heavy copper PCB?
A PCB with copper thickness typically above 3 oz (105 µm), designed for high current and thermal performance.
How much current can a heavy copper PCB carry?
Depending on trace width and copper thickness, heavy copper PCBs can carry tens to hundreds of amperes.
Why are design rules different for thick copper PCBs?
Thicker copper affects etching behavior and requires wider traces and spacing to maintain manufacturability.
Can heavy copper and standard copper be combined?
Yes, hybrid designs allow high-current and signal layers to coexist on the same PCB.
Engineering Expertise
Content reviewed by the Aspocomp NPI Team – specialists in heavy copper PCB manufacturing and power electronics applications.
Aspocomp has extensive experience in producing high-reliability PCBs for demanding industries. Our expertise in heavy copper processing, lamination and plating ensures reliable performance even under extreme electrical and thermal stress.
Power Your High-Current Design with Heavy Copper PCBs
Our engineers support:
- heavy copper PCB design
- thermal optimization
- manufacturability analysis
- material selection