Innovative tin electrolyte combining high technical standards with significant cost saving potentials

Abstract

A new MSA based, fluoroborate-free and foam reduced pure tin electrolyte, Niveostan ™*, has been developed to combine excellent technical performance with significant cost saving potentials. It consists of one additive only which can be easily analyzed by UV. The additive includes already an anti-oxidant to suppress the Sn (IV) formation during processing.The electrolyte provides a unique deposit that exhibits, due to smooth morphology and the large crystal grain size, a lower tendency to whisker formation compared to other electrolytes. In a FIB study this morphology as well as the intermetallic phase creation has been investigated on copper base materials. The electrolyte shows a superior high CD performance and an excellent solderability even after severe storage conditions and a high and reliable reflow performance through its "Big-grained Flat Morphology". The electrolyte also allows cost savings with respect to additive consumption, tin and MSA concentration. The tin and MSA concentrations during operation are comparably low in high speed application and allow significant savings in the overall running costs. The additive is very stable as shown in HPLC and Mass spectrometer analysis and mainly consumed by drag-out. The additive includes already an antioxidant to suppress the Sn (IV) formation very efficiently during processing as shown in a benchmark analysis. Furthermore the electrolyte can be used at room temperature even for high speed application due to its excellent HCD performance.