Thermal Structure Engineering for Thick Copper PCBs: Paths, Vias & Spreading

While thick copper inherently improves thermal conductivity, effective heat management in power PCBs requires deliberate thermal architecture. This paper moves beyond simple conduction to focus on designing continuous, low-resistance thermal paths. We analyze the role of internal copper planes as spreaders, the optimization of thermal via diameter, density, and fill materials, and the critical interfaces between the device, PCB pad, and external heat sinking solutions. The goal is to minimize thermal gradients and prevent hotspot-induced failure.

• Conduction-Dominated Cooling: Why heat flows through copper, not dielectric.
• Thermal Path Design: Creating continuous vertical and lateral paths from heat source to sink.
• Internal Planes as Spreaders: Optimizing plane layer location and copper weight.
• Thermal Via Engineering: Comparing via diameter, plating thickness, density, and filled vs. unfilled performance.
• Interface Management: Thermal pad design, direct copper contact, and thermal interface materials (TIMs).
• Heat Sink Integration: Attachment methods and minimizing contact resistance.
• Gradient & Stress Management: Mitigating warpage and delamination from CTE mismatch.