Solder bumps are frequently the sites of defects that cause continuity failures in ceramic flip chip packages. In concurrent technology the solder bump is a multi-layered structure containing several interfaces. Conventional c-SAM imaging alone cannot delineate subtle bump defects. In this article we present experimental results that document the nature of interface defects in multi-layered solder bumps as well as their acoustic signatures. The acoustic signatures obtained from defective bumps are contrasted with the signals obtained from pristine bumps and the sensitive nature of these signatures to defects is highlighted.