Effects of Die-Attach Material and Ambient Temperature on Properties of High-Power COB Blue LED Module

With the increasing demand of high-power light-emitting diode (LED), multichip modules have made great progress. A die-attach layer as the first-level packaging has a most significant impact on the thermal performance of a power module. In this paper, we introduce a novel die-attach material, nano silver paste, which can be used for connecting multichips on the substrate. This nano silver paste has a higher melting temperature and thermal/electrical conductivity than the conventional Sn3Ag0.5Cu solders and silver epoxy films. In addition, Al₂O₃ ceramic substrates were used to form a high-power LED chip-on-board architecture because of their high thermal conductivity and low coefficient of thermal expansion. Recently, because of their ability to emit high brightness, LED packages are being exploited for the automotive, aircraft, space exploration, nuclear industries, and in most cases are exposed to harsh environments. Therefore, the performance and stability of LED packages will be the key to assuring the reliability of LED modules. In this paper, the properties of the LED modules bonded separately with nano silver, Sn3Ag0.5Cu, and silver epoxy and operating under various ambient temperatures from 27°C to 100°C were determined. The test results showed that the nano silver paste is a very promising die-attach material for high-power multichip modules packaging.