Copper Coin PCB : A Solution for Heat Dissipation

In the fast-evolving electronics industry, devices are becoming smaller, faster, and more powerful, while also coming in a compact size. Power is no longer a problem, but packing the device into a smaller form factor presents a serious challenge. Whether we are working on a power converter, LED lighting module, automotive ECU, or 5G communication device, the excessive heat reduces performance. It shortens the component lifespan. This is where Copper Coin-Embedded PCBs become a smart, modern solution for better heat dissipation. Embedding a solid copper slug directly into the PCB acts as a heat sink, transferring the heat flux rapidly away from the critical devices. In this discussion, we will explore what copper coin-exposed boards are, their function, manufacturing process, and the benefits and applications.

What is Embedded Copper Technology?

Copper Inlay is a method to cool the PCB copper coin or chip, in which a raised part is built. Most PCB materials, such as FR4, are low-conductivity materials for heat dissipation. The Incorporation of copper gives a short, low-resistance path for heat transfer through the outer layer or to a heatsink. This reduces part temperatures and increases the product life cycle. It is great for compact, high-power, and heat-sensitive electronic designs.

What is Copper Coin PCB?

A copper Coin-Inserted PCB is a printed wiring board in which a copper (coin or slug) is incorporated into the board in the heat-generation components. This copper coin will enable direct thermal coupling to the other side of the PCB (or heatsink), providing rapid, low-loss heat transfer.

For conventional PCBs, heat spreading is facilitated by copper layers and thermal vias. The issue is that FR4 does not transfer heat very well (~0.3 W/m·K), whereas copper can conduct heat at 401 W/m · K. This significant contrast makes copper coins very useful for thermal imaging.

Why Heat Dissipation is a Critical Concern

Because every device comes with a conversion efficiency, if the conversion is 90% efficient, then 10% of energy is dissipated as heat. That’s why MOSFETs & IGBTs are hot to the touch, and even a BGA processor or a power IC can get hot! And they need an active cooling unit to faster dissipate the heat. Circuit miniaturisation involves more components in less space, generating internal heat within the PCB. If the board cannot dissipate this heat rapidly:

• Components exceed safe operating temperatures.
• Device performance becomes unstable.
• Solder joints weaken over time.
• Product reliability and lifetime drop significantly

This makes smarter thermal management a necessity rather than an option.

Why Use Copper Coins in PCBs?

As electronics continue to push higher power density, thermal control becomes increasingly crucial. Copper coins are chosen because they maximise heat transfer efficiency, keep PCB size very small without large external heatsinks, and are perfect for running high-wattage and high-frequency devices with precision. Copper coins offer a vertical heat conduction path that is far superior to conventional PCB thermal techniques.

How Copper Coin-Embedded PCBs Work

It’s a simple idea, just put a copper slug under the device that needs thermal spreading (power IC, MOSFET, LED, and BGA). Keep the copper coin flush with the surface or raised to contact a nearby heatsink or the chassis itself.

Working Principle Breakdown:

This provides a direct path, reducing heat resistance and allowing increased performance under extreme loads.

Copper Coin-Embedded PCB Fabrication Method:

High-precision milling and controlled bonding are required for making a copper coin PCB. The process generally includes:

1. Board Pre-Processing: Inner layers are prepared, leaving a cavity location for the coin.

2. Cavity Milling: A slot or pocket is milled with strict tolerances for a precise coin fit.

3. Coin insertion: A flat or step copper coin is placed into the cavity consciously.

4. Bonding / Filling: A resin, solder, or press-fit encapsulation attaches the coin and eliminates air gaps.

5. Surface treatment: ENIG, OSP, or HASL surface finish for enhanced solderability and oxidation resistance.

6. Testing: X-ray and thermal performance testing ensure bond integrity & heat conduction.

This image can be most effectively sited just after the description of a process in order to clarify the meaning for users.

Structure and Types of Copper Coins Used in PCBs

During PCB fabrication, copper coins are inserted into precisely machined slots within the board and positioned directly beneath high-power components to create an efficient, low-thermal-resistance heat-conduction pathway. Copper coin integration is generally classified into two configurations:

• Embedded Copper Coin PCB: In this method, the copper is inserted into a routed cavity and laminated into place during PCB lamination. The coin is bonded to the PCB stack with strong mechanical adhesion and very low thermal resistance. This is a favourite technique when both structural strength and thermal performance are high.

• Buried Copper Coin PCB: In this configuration, the copper coin is placed into a milled recess and encapsulated using prepreg layers during the lamination cycle. The coin remains fully enclosed within the PCB structure. Although it offers similar thermal advantages, it is typically selected when the copper must remain internal and not exposed to the outer surface.

Copper coins can be manufactured in multiple geometries, such as T, L, stepped, or other customised profiles to increase heat-transfer contact area and optimise performance in space-constrained PCB layouts.

Advantages and Applications of Copper Coin-Embedded PCBs

The Copper coin PCB provides better heat transfer as well as anti-voltage reduction, and it adds a unique temperature drop (5-10°C) with the assurance of the anti-break feature, enabling longer product life. Their heat path construction outside the PCB surface helps avoid the need for bulky heatsinks, preserving design flexibility and a cooler working environment, and also saves costs for devices where space, airflow, or noise is a concern. They may also be used as cheaper alternatives to solid metal-core PCBs.

Due to these advantages, copper coin technology has been adopted in high-power LED, automotive ECU, motor drivers, 5G telecom hardware, power electronics, industrial control systems, GPU/BGA boards, and RF/microwave devices.

Design Considerations

When developing copper coin PCBs, the following are the things engineers need to take into account:

• The right size coin in diameter, shape, and thickness
• Proper insulation distance from high-speed signal traces
• Coin material plating to reduce oxidation
• Avoiding air gaps for the best thermal conductivity
• Flatness control to ensure component soldering quality

It is highly recommended to consult with the PCB manufacturer during the early stages of the process.

Conclusion:

With the increased performance being packed into smaller footprints, heat dissipation has become a primary design issue for electronic systems. Copper Coin-Embedded PCBs provide a smart, reliable, and highly efficient thermal solution at the PCB level. They enable fast heat transfer directly from the source. By minimising thermal resistance and preventing components from conducting heat to each other, this technology extends product life, increases system efficiency, and ensures reliable operation. With advanced capabilities in manufacturing copper coin PCBs, JLCPCB offers engineers a reliable and affordable solution to enhance heat dissipation at the board level.