Abstract
In today's electronic industry of shrinking circuit boards and shrinking semiconductor integrated circuits (IC), semiconductor companies have to be creative in providing devices with more circuitry on less silicon. Copper Bond over Active Circuit (BOAC)/Copper over Anything (COA) processes allow routing and bonding to thick top level metallization on the LinBiCMOS technology node. This paper discusses failure analysis (FA) techniques and approaches on un-passivated BOAC, and explains a generic BOAC/COA process. The approach to FA of BOAC involves package inspection-non intrusive analysis, decapsulation, die inspection, and defect identification/root cause analysis. Case studies are presented to explain the specific FA steps. Fault isolation involving BOAC requires the strategic removal of copper traces and selective analysis of the failed circuitry. Liquid crystal and micro-probing have been used effectively in failure isolation.
