Description
What is a copper coin PCB?
A copper coin PCB is a PCB in which a solid copper coin, or copper block, is embedded into the FR4 board under a hot component. It is also called an embedded copper coin PCB or an embedded copper block PCB. Heat-generating components are mounted directly onto the copper block, so heat has a direct metal heat path out of the hot spot instead of passing only through FR4 and thermal interfaces.
The solid copper block also gives high-current capacity where it is needed. That makes a copper coin PCB well suited to localized hot spots in power devices, DC-DC converters, RF power designs and LED designs, while the rest of the board can keep normal FR4 routing. FX PCB has mass-production experience with FR4 copper inlay and embedded-copper structures.
Copper coin PCB vs. copper core PCB
A full copper core PCB uses a copper base across the board, while a copper coin PCB embeds copper only where heat is concentrated. Choose the embedded coin when only a local hot spot needs the strongest thermal path and the rest of the design should remain a multilayer FR4 board with routing on both sides.
Traditional methods of attaching copper or heatsinks to FR4 boards typically involve thermal interfaces and the Surface Mount Technology (SMT) process. While cost-effective, this approach introduces thermal resistance and complexity. By inserting the copper coin directly into the PCB structure, the embedded copper coin method creates a near-direct heat path, improves current handling, and allows the component to stand higher power loads than standard SMT assembly alone.
Copper coin PCB specifications
The table below gives the standard FR4 capability for copper coin PCBs from FX PCB.
| Layers | 2–12 |
| Board thickness | 0.3–4.0 mm |
| Copper foil | 1–10 oz |
| Line width / space | 0.05/0.05 mm |
| Hole copper | 25–150 µm |
| Surface finishes | OSP, ENIG, ENEPIG, immersion tin, lead-free HASL |
| MOQ | 5 pcs |
Production process of embedded copper coin PCB
The production process for embedded copper coin PCBs is more complex than standard PCBs because the copper coin and the FR4 board must be bonded and laminated together without depressions, resin overflow or cracks between the copper coin and the resin.
- Inner Layer Fabrication: Circuit patterning and etching.
- Precision Routing: Milling a precise slot or cavity for the copper coin insertion.
- Coin Insertion & Cleaning: Critical steps to ensure a contaminant-free bonding surface.
- Metallization & Plating: Ensures electrical and thermal connection to the surrounding layers.
- High-Pressure Lamination: A multi-stage cycle that bonds the layers and securely embeds the coin while controlling resin flow.
- Outer Layer Fabrication: Final patterning, drilling, and finishing.
Copper Coin PCB Inner Layer Fabrication
Copper Coin PCB Outer Layer Fabrication
Frequently asked questions about copper coin PCBs
What is a copper coin PCB?
A copper coin PCB embeds a solid copper coin, or copper block, into an FR4 board under a hot component, giving a direct metal heat path and high-current capacity for a localized hot spot.
How is a copper coin PCB different from a copper core PCB?
A copper core PCB uses a copper base across the board, while a copper coin PCB embeds copper only at local hot spots. The coin design is therefore suited to multilayer FR4 boards where only part of the board needs the strongest thermal path.
Which board types and thicknesses can a copper coin PCB be combined with?
A copper coin PCB is combined with an FR4 board. The FR4 capability in the table above covers 2–12 layers and a board thickness of 0.3–4.0 mm.
What surface finishes are available?
OSP, ENIG, ENEPIG, immersion tin and lead-free HASL are available.
What is the minimum order quantity?
The minimum order quantity is 5 pcs.
What applications suit a copper coin PCB?
Localized hot spots in power devices, DC-DC converters, RF power designs and LED designs are typical applications.
How do I order a copper coin PCB?
Send your copper coin PCB requirements, including your hot-spot layout and the specification items in the table above, to FX PCB for a quote through the contact page linked below.
Request a quote for your copper coin PCB
For assembled boards, FX PCB can support the full build: as a PCBA manufacturer, FX PCB can assemble copper coin boards as well as fabricate them.
Send your copper coin PCB requirements to FX PCB for a quote. Contact FX PCB to discuss your power device, DC-DC converter, RF power or LED design.
For background on the technology, see What is a copper coin PCB?
