In PCB (Printed Circuit Board) design, full-board heavy copper plating can enhance current-carrying capacity, but it also brings major drawbacks, including high process complexity, elevated costs and compromised signal integrity. Against this backdrop, localized heavy copper (also referred to as integrated thick copper regions) has emerged as a critical solution, precisely balancing high-current transmission and efficient thermal management while maintaining cost control, manufacturability and signal stability.
By closely tracking PCB technology trends, Lieban has prioritised localized heavy copper processes to meet increasingly stringent downstream requirements for high current capacity, high heat dissipation, lightweight design and high reliability, positioning this technology as a key enabler in the high-voltage electrification era.
I. Core Advantages: Why Localized Heavy Copper Outperforms Copper Block Solutions
Although both localized heavy copper and attached copper blocks aim to reinforce copper layers locally, they differ fundamentally in stability, cost efficiency and design flexibility.
1. Substrate Stability: From Latent Risk to Structural Integrity
· Copper block approach: Pre-fabricated copper blocks are soldered onto reserved PCB pads. The presence of solder interfaces introduces risks of detachment, displacement or delamination under harsh conditions such as high temperature, humidity, salinity or vibration—directly undermining end-product reliability.
· Localized heavy copper: Copper thickness is increased in designated PCB areas on a one-to-one basis, forming an integrated structure with no intermediate bonding layer. Even under extreme operating conditions, structural integrity remains intact, effectively eliminating reliability risks.
2. Cost Control: From High Scrap to High Utilisation
Copper block solutions suffer from significant material waste and inventory pressure:
· CNC cutting and polishing limit material utilisation to around 60%, generating substantial copper scrap;
· Design iterations require new copper blocks, increasing tooling costs and inventory risk.
Localized heavy copper uses chemical deposition and masked electroplating to integrate thick copper directly into the PCB:
· No cutting losses, resulting in more predictable and controllable costs;
· Engineers can freely adjust copper geometry across product generations without inventory concerns, eliminating iteration-related waste.
3. Design Freedom: From Compromise to Optimisation
· Copper blocks: Require reserved space for solder pads and component clearance, forcing designers to accommodate fixed copper dimensions and often compromise original layouts.
· Localized heavy copper: Thickness and geometry are defined directly in the PCB layout, allowing precise optimisation of copper thickness, area and layer structure without sacrificing performance.
4. Thermal Performance: From Delayed Transfer to Direct Conduction
Thermal efficiency depends on heat paths and interface resistance:
· Copper blocks: Heat must pass through PCB substrate and solder layers before reaching the copper block, increasing thermal resistance and response time.
· Localized heavy copper: Integrated copper layers conduct heat directly from the source, minimising interface resistance. Thermal expansion remains synchronised with the substrate, preserving both thermal and electrical performance.
5. Assembly Compatibility: From Dimensional Constraints to Seamless Integration
· Copper blocks: Protruding structures alter PCB height and volume, often requiring additional mechanical redesign.
· Localized heavy copper: Adds minimal thickness and preserves original board dimensions, ensuring smooth downstream assembly and system integration.
II. Practical Applications: Localized Heavy Copper in High-Power Systems
Localized heavy copper has already achieved large-scale adoption in high-voltage, high-power applications.
Planar Transformers: A Benchmark for High Frequency and Power Density
In 100 kW onboard chargers (OBCs), planar transformer design prioritises compactness and thermal efficiency. Using localized heavy copper, Lieban achieved:
· 6 oz thick copper coils capable of carrying 100 A at 50 kHz, reducing volume by 60% compared with traditional enamelled wire windings;
· Direct bonding of thick copper coils to aluminium nitride ceramic substrates, reducing thermal resistance to 1.2°C/W without additional heat sinks—cutting both weight and cost.
Similarly, in automotive motor applications, traditional hand-wound stators face challenges of high cost, bulk and weight. The industry is increasingly adopting PCB-based coil designs, with localized heavy copper enabling integrated windings that support lightweight, high-reliability next-generation motors.
III. Conclusion: Localized Heavy Copper as a High-Voltage Imperative
As electrical systems evolve toward higher voltage, higher power and greater compactness, PCB current-carrying and thermal requirements have reached a new threshold. Localized heavy copper is no longer optional—it has become essential for achieving core performance targets and maintaining market competitiveness.
By combining superior stability, cost efficiency and design flexibility, localized heavy copper is driving PCB technology from standardisation toward precision engineering, laying a solid foundation for the electrified future.
Source：China Software Developer Network