Surface Roughening of Direct-Bond-Aluminum Substrate Exposed to Large △T (>300oC) Cycling

摘要

Direct-bond-aluminum (DBA) substrates for power module packaging are being considered as a betterrnalternative to direct-bond-copper (DBC) substrates because they have a longer temperature-cyclingrnlife. In our attempt to use DBA substrates for high temperature module packaging, we subjected DBArnsubstrates to a large temperature cycling between -55℃ and 250℃. Although no delamination of aluminumrnfrom base ceramic was found, we observed significant roughening on the substrate surface.rnThe surface roughness was measured by a contact profilometer and found to increase by over 10rntimes after several hundreds of cycles. This significant surface roughening may pose a concern onrndie-attach reliability for high-temperature applications.