Advanced packaging methods for high-power LED modules

Abstract

LED luminaires are already beyond retrofit systems, which are limited in heat dissipation due to the old fitting standards. Actual LED luminaries are based on new LED packages and modules. Heat dissipation through the first and second level interconnect is a key issue for a successful LED package. Therefore the impact of known bonding technologies as gluing and soldering and new technologies like sintering and transient liquid phase soldering were analyzed and compared. A realized hermetic high power LED package will be shown as example. The used new techniques result in a module extremely stable against further assembly processes and harsh operating conditions.

Effect of (Ni, Au)3Sn4 growth on the thermal resistance of Au-20 wt% Sn solder/ENIG joint in flip-chip LED packages

“…The IMCs formed using Au-20 wt% Sn solder on the phase diagram are Au 5 Sn, AuSn, AuSn 2 , AuSn 4 . 25,26) Au has interstitial diffusion with Sn, and the diffusion rate is very fast. Therefore, diffusion proceeds in the Au-20 wt% Sn interfacial reaction, and phase transitions occur in the order of AuSn, AuSn 2 and AuSn 4 .…”