Reliability Evaluation for a Wet-Plated Electrode with a Al/Al2O3/Cu Insulated Metal Substrate

The heat sink in LED chips has been a major challenge for high-power LED module design. Elevated chip temperatures cause adverse effects on LED performance, lifetime, and color. An insulated metal substrate (IMS) is the commonly used substrate and has good thermal performance and low cost. This study used an aluminum IMS with good heat radiation efficiency to solve these problems. The most traditional IMS technique is electrochemical anodization. There are various methods to form electrical conductors on anodized aluminum. In this study, the anodization process was performed on an aluminum substrate using a phosphoric acid electrolyte to form the AAO layer. This investigation confirmed that electroless Ni-P plating for seed layers could be used to substitute for the Cu-sputtering process. Our evaluation of the reliability of the different thicknesses of aluminium anodic oxidation and the electro-plated Cu electrode revealed that the maximum peel strength was 1.6 kgf/cm and it was obtained at an anodizing time of 1000 minutes. The TCT, the solder shock test and the solderability test showed that the substrates were not delaminated. †(Received October 15, 2012)