A reliable wire bond connection for integrated circuit devices is an important gauge in assuring a high-quality product. In comparison to pure copper wires, which are used for low-cost assembly but have oxidation problems, Palladium Coated Copper (PCC) bond wires were used to increase wire robustness, provide an advantage in applications at high temperatures, and meet criteria for good loop stiffness and hardness. However, decapsulated samples have been rejected by reliability engineering, and rework has been needed because wire discoloration was mistakenly identified as oxidized bond wires creating delays in producing the Failure Analysis (FA) result as well as wasting unnecessary resources in the process. The wrong callout happens 47.8% of the time. Through the investigation of chemical compositions, the topography of materials, and the evaluation of bond strength distribution, with some use of statistical analysis tools, this study explains how the issue was resolved. As a consequence, the wrong callout was effectively eliminated.

High temperature gold/tin eutectic (80 Au/ 20 Sn) solder is used in manufacturing for multiple reasons. These motives may include the ability to post solder a part/device without reflow, high temperature field applications, and allow soldering to thick Au layers without the possibility of precipitating AuSn4 brittle intermetallics. In the following military case, Au/Sn eutectic was employed because of high temperature service and the guarantee of no occurrence of gold embrittlement when soldering to the thick Au outer plating. The Au was plated over an electroplated nickel (Ni) layer on a Kovar (iron/nickel/cobalt) housing. The soldering resulted in an extremely poor bond strength of a duroid circuit to the Kovar housing. The results showed contamination in the supplier’s electroplated Ni bath caused the plating to have poor bond strength. The failure occurred within the Ni plating layer.