Fabrication and thermal analysis of flip-chip light-emitting diodes with different numbers of Au stub bumps

The thermal performance of flip-chip (FC) light-emitting diodes (LEDs) with different numbers of Au stub bumps has been investigated by using thermosonic bonder. The LEDs were mounted on the aluminium nitride (AlN) sub-mounts which have superior thermal conductivity (230 W/mK), and the high power Chip-on-Plate (COP) package was proposed to be used for our measurement. In order to understand the thermal performance of the high power FC-LEDs, the experimental measurement and finite-element model (FRM) numerical simulation have been used. It is found that the thermal performance of our 1 × 1 mm2 FC-LEDs can only be improved when using at least 6 Au stub bumps as interconnected metals. Moreover, the surface temperature of FC-LEDs is significantly reduced while using 20 Au stub bumps.