New LITESURF plating for the mitigation of whisker risks in press-fit applications

Due to restrictions on lead usage often resulting in the use of pure tin deposits, coupled with global miniaturization, the unpredictable risks of Sn whisker growth rises, especially in highly stressed coating applications. The ability to prevent whisker growth is particularly important for the growing implementations of solderless press-fit pin connections, where although very beneficial, produce high stress gradient conditions on the compliant pin's coating, leading to higher risks of whisker induced failures. Therefore, TE Connectivity has developed a new production level tin-whisker free technology through the application of an electroplated Bismuth (Bi) based deposit (LITESURF), tailored for reliable press-fit pin connections with the ability to accommodate for further miniaturization trends. In this work we discuss the properties of LITESURF plating and its universal use in various PCBs (iSn, iAg and OSP) along with how it is a promising tin alternative for press-fit applications, which can reduce the risk of whisker growth related failures by orders of magnitude.