I.What is Heavy Copper PCB

Heavy copper PCB or sometimes called thick copper circuit board is a printed circuit board (PCB) characterized by a thicker copper foil bonded on a glass epoxy substrate, usually thicker than the commonly used standard (such as 35μm) to achieve a sufficiently thick copper plating in the hole. This circuit board is used in circuit designs that require higher current carrying capacity and lower resistance and inductance values to reduce the generation of noise voltage. Heavy copper PCB is generally referring to the PCB with 3oz copper thickness, when the layout space is limited and not able to improve the current carrying ability by increasing line width, using heavy copper PCB can effectively meet the requirement of current carrying and improve the heat dissipation of PCB.

II.Advantages of Heavy Copper PCB

1. Carry big current

Heavy copper PCB can carry enough current within limited space, effectively improve the power density of circuit board.

• Excellent Heat Dissipation

Heavy copper PCB can transfer the heat better, thus improve the heat dissipation performance, ensure the normal working temperature of PCB and electronic components, which is very important for high power and heat-prone circuit

• Increased Mechanical Strength

Thick copper layer can improve the mechanical strength of PCB and make it more stable and durable.

• High Reliability

Increased copper thickness makes the circuit board can bear the thermal strain under higher load. Therefore, heavy copper PCB can help to control, convert or distribute electric power more reliably and effectively.

III.Applications of Heavy Copper PCB

1. Power Supply Equipment
2. Power supply module: used for server power supply and industrial power supply. The heavy copper layer can carry big current and reduce generating heat.
3. Inverter, like solar inverter and wind energy inverter. The heavy copper circuit can bear high current and effectively dissipate heat.
4. Automotive Electronics
5. Electric vehicle: used for battery management system(BMS) and motor controller
6. Traditional vehicles: used for engine control unit(ECU) and power supply distribution system
7. Industrial Control
8. Motor drive: used for high power motor drive and controller
9. PCL: used for industrial automation control system with high power
10. Communication Equipment: communication station with high power radio frequency module and power modules
11. Medical equipment: medical equipment has high requirements for reliability and heat dissipation, heavy copper PCB can meet such requirements, for example, medical imaging equipment, healing equipment and life supporting equipment.
12. Consumer Goods: in the consumer goods area, heavy copper PCB is mainly used for high power goods, like air conditioner, refrigerator, micro oven

IV. Points Need to Pay Attention When Designing Heavy Copper PCB

Since heavy copper PCB needs to bear a higher load and current and is used under serious conditions, the correct design of heavy copper PCB is of great importance. Here are some points when designing heavy copper PCB;

1. Current carrying capacity design

• Choose a suitable copper thickness that can work for your board according to the current, for example, 3oz/ft2 or more.
• Calculate the line width according to the IPC-2152 standard to ensure the board can carry the current without generating too much heat.
• Increase quantity and dimension of via to carry higher current and lower resistance.
• Optimize the layout to avoid overheating due to improper arrangement.

2. Thermal management

• Thermal release design: add more thermal vias to conduct the heat to other layers or heat sinks and use a large area of copper for better heat dissipation.
• Proceed with thermal simulation during the design process, recognize the hot area, and optimize the circuit layout.
• Component layout: load the high heat generation components, for example, power MOSFET and transformer, to the area with nice heat dissipation performance. The heat-sensitive components should be away from high heat-generating components.
• Heat dissipation base material: the base material must withstand high temperatures, and the tg value should be over 130℃ if using FR4. Or use high thermal conductivity material, like metal base or ceramic material.

3. Signal integrity

• Impedance control: the thickness of heavy copper PCB will influence the impedance, the line width and space should be calculated accurately.
• Reduce crosstalk: Increase the signal line space, avoid long parallel lines, and use the ground plane to isolate high-frequency signals
• High-frequency signal layout: keep the high-frequency signal paths as short as possible to reduce reflections and losses, and use differential pair routing to reduce noise.

4. Mechanical strength and reliability

• Laminating process: the laminating process of heavy copper PCB is complex, and the bonding strength between the layers needs to be ensured to avoid the delamination issue due to uneven copper thickness.
• Board thickness: the heave copper layer will increase the total thickness of the PCB, the designer needs to consider the assembly and mechanical strength.
• Bending and stress: better avoid too many vias in the heavy copper area to reduce mechanical stress and add reinforcement design at the PCB border and assembly holes.

5. Component and circuit Layout

• High-power components layout: the high-power components should do a centralized layout for better heat dissipation and current management. The high-power components should stay away from sensitive signal components.
• Power source and ground plane: when designing a multilayer PCB, the complete power source and ground plane are designed to reduce noise and circuit loop impedance.
• Optimize layout: keep the high current paths as short as possible to reduce resistance and power loss. Use a star or net wiring to ensure the circuit distribution is even.

6. Cost Control

• Choose material: choose cost-effective base material and copper if the board can meet the performance requirement.
• Optimize design and layout to reduce layer count and board size to lower the manufacturing cost.
• Manufacturing process: The designer should have close communication with PCB suppliers to understand their capabilities, choose the proper manufacturing process, and avoid over-design.

V. The Future of Heavy Copper PCB

The future development prospects of thick copper PCB are very broad, mainly benefiting from the growing demand in electric vehicles, 5G communications, new energy and industrial automation. At the same time, material innovation, manufacturing process improvement and design tool upgrade will promote the further development of thick copper PCB technology. Despite the cost and technical challenges, the core position of thick copper PCB in high-power electronic devices is irreplaceable and will play an important role in more fields in the future.

Jerico PCB has nearly 20 years of experience supporting our customers with PCB and PCBA fabrication service, heavy copper PCB fabrication is also our advantage. With advantages in technology, process, quality and service, we can maintain competitiveness in the heavy copper PCB market and meet customer needs. If you have any heavy copper PCB project and want to find a suitable partner, Jerico PCB is here for you.

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