Interfacial Reaction and Wetting Behavior Between Pt and Molten Solder

Abstract

Platinum does not oxidize easily, and has slow reaction rates with Sn-based solders. Due to these two positive attributes, a single platinum layer has the potential to replace both the oxidation protection layer and the diffusion barrier layer in the underbump metallurgy of flip-chip devices. To evaluate this potential further, the dissolution rate and the wetting properties of Pt were investigated in this study. It was found that Pt did have a dissolution rate less than half that of Ni, currently the most popular barrier layer material. The wetting properties of Pt were not as good as those of Ni but were nevertheless still acceptable for industrial applications. In short, as far as the dissolution and the wetting characteristics are concerned, Pt is an effective top surface layer for use in underbump metallurgy.

Wettability and interfacial reactions between the molten Sn–3.0 wt%Ag–0.5 wt%Cu solder (SAC305) and Ni–Co alloys

“…Eutectic and near eutectic Sn-Ag-Cu solders are promising lead free solders [14][15][16][17][18]. Past research explores the wetting properties [5,6,[18][19][20][21][22][23][24][25][26][27][28][29][30][31] and interfacial reactions [14][15][16][17][18] between Sn-Ag-Cu solders and various substrates, but not for Sn-Ag-Cu/Ni-Co systems. In this study, the Wilhelmy type wetting balance method determines the wetting properties [32].…”