Design for Reliability: PCBs - DfR Solutions
Design for Reliability: PCBs - DfR Solutions
Design for Reliability: PCBs - DfR Solutions
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ENIG: Primary <strong>Reliability</strong> Risks• Black pad drivers• Phosphorus content• High levels = weak, phosphorus-richregion after soldering• Low levels = hyper-corrosion (black pad)Insufficient Phosphorous will not preventcorrosion during the highly acidicimmersion gold (IG) process.• Cleaning parameters• Gold plating parameters• Bond pad designs• Causes a drop in mechanical strength• Difficult to screen• Can be random (e.g., 1 pad out of 300)Images of Black Pad• Ni-Sn intermetallic produces a brittleinterface when used with SAC solder.Phosphorus-Rich Dark Streak© 2004 - 2007 2010
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