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AUGUST 2020 I PCB007 MAGAZINE 59 different conditions were compared. The for- mation of pores, in this case, acts as an indi- cator of a disturbed initial palladium growth and potential defects in the layer formation (Figure 7). The result clearly indicates that the Pd-Core® offers a significantly improved bath sensitivity toward potential contaminations in the process. Even with a contaminated rinse, no effect on the formation of pores in the palladium layer can be seen. In comparison to the conventional pro- cess, the Pd-Core® appears more robust and can help to ease the handling of the whole ENEPIG process. Summary and Conclusion This article presented a new plating bath for electroless plating of pure palladium layers. The soldering and bonding tests that were con- ducted showed that the layer performance is at least as good as the performance of the mass production process, which is available in the market. Besides the high reliability of the sur- face finish, the new process offers significant cost savings due to its reduced precious metal content and long lifetime. Further advantag- es are the increased process robustness and reduced sensitivity to contaminations in the process. These ease process handling and help to reduce maintenance efforts. PCB007 Note: This article was originally titled "Pure Palladium Plating for ENEPIG: Improved Process Robustness for Lower Cost." References 1. R Nichols, G. Ramos, and S. Heinemann, "A Study of the Initiation Speed of the Palladium Within an Electro- less Nickel, Electroless Palladium, and Immersion Gold (ENEPIG) System With Regard to Solder Joint Reliability," TPCA IMPACT, October 2017. 2. B. Schafsteller, S. Nelle, G. Ramos, D. Tews, and M. Rosin, "ENEPIG: How the Process Characteristics Influ- ence the Layer Performance," IPC APEX EXPO, February 2020. Britta Schafsteller, global product manager for selective finishing at Atotech in Berlin, Germany. Gustavo Ramos, global product director for selective finishing at Atotech in Berlin, Germany. Dirk Tews, EL R&D manager for selective finishing at Atotech in Berlin, Germany. Dimitri Voloshyn, development engineer for selective finishing at Atotech in Berlin, Germany. Figure 7: Process sensitivity toward rinse cleanliness.