Copper-Core MCPCB With Thermal Vias for High-Power COB LED Modules

Abstract

To improve thermal performance of high-power chip-on-board multichip LED module, a copper-core metal core printed circuit board (MCPCB) substrate with copper filled microvias is introduced. As a reference, the performance is compared with alumina module with the same layout by means of thermal simulations and measurements. Up to 55% reduction in the thermal resistance from the LED source to the bottom of the substrate is demonstrated. The excellent performance of the Cu MCPCB module is due to copper-filled microvias under the blue LED chips that occupy the majority of the multichip module. The conclusion was verified by measuring increased thermal resistances of red chips without thermal vias on the Cu MCPCB module. However, as the blue LEDs dominate the thermal power of the module, they also dominate the module thermal resistance. The thermal resistance was demonstrated to correspond with the number of vias as lower thermal resistance was measured on modules with larger number of vias. The Cu MCPCB was processed in standard PCB manufacturing and low cost material, FR4, was utilized for the electrical insulation. Thus, the solution is potentially cost-effective despite the higher cost of copper in comparison with aluminum that is the most commonly used MCPCB core material.