Die attach materials play a key role in functional performance and reliability of light-emitting diodes (LEDs). Selection of a suitable die-attach material for a particular chip structure and application depends on several considerations. These include performance (light output and thermal dissipation at operating temperature), reliability (lumen maintenance and mitigation of thermo-mechanical stresses over lifetime), packaging process (equipment, throughput and yield) and cost factors. In this study we used different die-attach materials to package lateral, vertical and flip-chip LEDs. Optical and electrical performance of the assembled packages was then characterized by junction temperature, luminous flux and efficacy measurements in an integrating sphere.
This paper discusses the effect of die-attach material properties and chip structure on LED functional outputs. The results clearly indicate that while optical characteristics of the die-attach material dominate the light output of lateral LEDs, junction temperature management is important for achieving optimal functional performance for higher power vertical and flip-chip LEDs.
This white paper sponsored by Alpha Assembly Solutions.