High Reliability Pb-Free Printed Circuit Board Assembly
The solderability and reliability of SnAgCu and SnAgCuSbBiNi lead-free solders were assessed against SnPbAg solder on a range of PCB finishes. A novel solderability test has been developed to assess the solder system’s ability to realign when a deliberately inaccurate solder stencil printing process was applied. This has shown to be an excellent way to compare PCB finishes and solders, as well as define process parameters. Electroless Nickel Immersion Gold (ENIG) finish proved to give the best solderability and the optimum process parameters were also found. SnPbAg solder has shown superior thermal cycling performance compared to SnAgCu.
Daizhong Su, Qingbin Zhang and Shifan Zhu
S.D.T. Weller et al., "High Reliability Pb-Free Printed Circuit Board Assembly", Key Engineering Materials, Vol. 450, pp. 9-12, 2011