Investigation on the Influence of Nickel Contamination of Plated Through Hole (PTH) Solder Joint Integrity

Abstract

An investigation was conducted to examine the validity of current industry maximum nickel contamination limits, which are established to ensure plated through hole solder joint integrity, for SnPb and SAC305 solder baths. Test vehicles were processed using three levels of nickel contamination for each solder: 0.01 wt.%, 0.02 wt.%, 0.05 wt.% for SnPb solder and 0.05 wt.%, 0.07 wt. %, 0.10 wt.% for SAC305 solder. The test vehicles were subjected to thermal cycle testing in accordance with the IPC-9701 specification. Based on this testing, the authors recommend that the allowable nickel contamination levels listed in the IPC-J-STD-001 specification (Table 3-1, Maximum Limits of Solder Bath Contaminant) be 0.05 wt.% for SnPb Assembly, 0.05 wt.% for SnPb Preconditioning, and 0.10 wt.% for SAC305 Pb-free Assembly.