Heavy‑copper Copper Based PCB for high‑current power modules

Copper Based PCB (copper-based printed circuit board) is a high-performance special PCB that uses a copper plate as the core substrate. Its structure is similar to that of aluminum-based PCB, generally consisting of three layers:
◈ Circuit Layer: Surface copper foil, used for circuit layout and component soldering to realize electrical connection.
◈ Insulating and Thermally Conductive Layer: The intermediate layer between the circuit layer and the copper substrate, which needs to balance three core properties: high thermal conductivity, reliable electrical insulation and stable bonding performance.
◈ Copper Substrate Layer: The core base material is high-purity copper or copper alloy. It is the core part of heat conduction and mechanical support, with extremely high thermal conductivity.
The design purpose of copper-based PCB is to solve the heat dissipation problem of ultra-high-power electronic devices, which is a higher-level heat dissipation PCB scheme than aluminum-based PCB.

Main Applications of Copper Based PCB

Copper-based PCB is aimed at scenarios with extremely high heat flux density and harsh heat dissipation requirements, and its application scope is more targeted than aluminum-based PCB, mainly including:
◈ High-power power electronics: High-power IGBT modules, high-frequency induction heating equipment, high-power inverters and rectifiers. These devices generate huge heat during operation, and copper substrates can quickly export heat to avoid device burnout.
◈ Aerospace and military electronics: High-power radar modules, satellite communication power supplies, missile-borne electronic components, etc. These fields have strict requirements on heat dissipation efficiency and environmental adaptability, and copper-based PCB can meet the high reliability requirements under extreme conditions.
◈ High-power semiconductor devices: Test boards for high-power chips, semiconductor laser driver boards, etc. It can ensure the stable operation of high-power devices during testing and working.
◈ Special industrial equipment: High-power ultrasonic equipment, high-frequency welding machines, industrial microwave equipment, etc. These equipment have high power density and require efficient heat dissipation solutions.

Advantages and Disadvantages of Copper Based PCB

◈ Advantages
● Ultra-high thermal conductivity: The thermal conductivity of pure copper is about 401 W/m·K, which is far higher than that of aluminum alloy (about 200 W/m·K) and FR-4 substrate (about 0.2 W/m·K). It can quickly transfer a large amount of heat generated by high-power devices, with the best heat dissipation effect among metal-based PCBs.
● Excellent thermal stability: Copper has a high melting point (1083°C) and stable thermal performance. It is not easy to deform or oxidize under high-temperature working conditions, and can maintain the structural integrity of the circuit board for a long time.
● Strong mechanical strength: Copper substrate has high hardness and rigidity, good resistance to impact and vibration, and is suitable for harsh working environments such as aerospace and industrial fields.
● Good compatibility with high-power devices: It can be perfectly matched with high-power components such as IGBT and MOSFET, reduce the thermal resistance between the device and the substrate, and improve the service life of the device.

◈ Disadvantages
● High cost: Copper is more expensive than aluminum, and the processing of copper-based PCB requires more precise processes (such as anti-oxidation treatment, cutting and drilling). The overall cost is much higher than that of aluminum-based PCB and FR-4 PCB, which is not suitable for low-cost applications.
● Heavy weight: The density of copper (8.96 g/cm³) is much higher than that of aluminum (2.7 g/cm³). The copper-based PCB is heavier under the same size, which limits its application in lightweight equipment such as consumer electronics.
● Easy to oxidize: The surface of copper is easy to form an oxide layer in the air, which will affect the welding performance and thermal conductivity of the substrate. Therefore, it is necessary to do a good job in surface anti-oxidation treatment (such as plating nickel, gold or organic coating), which increases the processing procedure.
● Difficult processing: Copper has high hardness and toughness, and it is easy to cause tool wear during drilling and cutting. Special processing equipment and processes are required, which increases the difficulty of production and the reject rate.
● Limited structural design: Similar to aluminum-based PCB, it is mostly designed as single-layer or double-layer board, and it is difficult to make multi-layer complex circuits, which cannot meet the needs of high-density wiring scenarios.