Issue link: https://iconnect007.uberflip.com/i/992528
30 PCB007 MAGAZINE I JUNE 2018 The plating mechanism and extended plat- ing time required to achieve approximate 100 nm gold thickness cannot satisfy corrosion ex- pectation. Gold plating into the pinhole is a demonstration that the plating process is pref- erential to the dissolution process in the case of SA-Au (Figure 7). The SA-Au process has not led to major lo- calized corrosion. The electron has resulted in preferential plating in pinhole rather than nick- el dissolution. Basic Assembly Data The previous section demonstrated that anomalous defects can be improved by apply- ing an electroless gold with autocatalytic char- acteristics. However, a cost effective, function- al performance is the litmus test for fabricators and OEMs. Form factor and bandwidth upgrades have rendered soldering as a significant consider- ation in the electronics assembly field. Good solder joint reliability (SJR) is the prime es- sential requirement. A recognized simulation tool for BDA/flip chip reliability is high speed shear testing (HSS). The target is to define the quality of a solder joint, specifically in terms of ductility. This is a method to assess resis - tance to impact. Figure 8 demonstrates that there is no sta- Figure 7: A representation of a pinhole post semi- autocatalytic electroless gold plating. Figure 8: HSS results by lifetime for semi-autocatalytic and reduction-assisted gold baths. 7