BUILDING IN RELIABILITY FOR SILVER DIE ATTACHED LIGHT-EMITTING-DIODES

In this paper, we present a failure analysis and reliability case hist ory of light emitting diodes (LEDs), used in a fibre optics transmitte r product, bonded using silver die attach epoxy. The observed failure mode was a reduction in light output of the transmitter device due to increased forward voltage after pulsed, high current operation which w as attributed to the electrical degradation of the silver die attach e poxy. Steps taken to design in reliability into the product involved e xperimental design to optimize the die attach process, evaluation of m ore robust epoxies which can withstand accelerated high temperature an d high current burn-in conditions, and the use of an improved die back -contact metallization system. Reliability performance of the die atta ch system was predicted and extrapolated to actual field application a nd burn-in conditions.