Solid-state Reactions And Stress Evolutions Between Snag And Ni(p) Thin Films

摘要

Phase transformations in SnAg-Ni_(80)P_(20) films were studied ex situ in parallel with in situ measurements of the corresponding transformation-induced stresses. Layered formation of Ni_3Sn_4 and Ni_3P phases at an early stage of a reaction between SnAg and Ni_(80)P_(20) films resulted in a tensile stress similar to the stress evolution in Sn-Ni_(80)P_(20) films, despite the additional formation of Ag_3Sn phase. Ag_3Sn phase did not significantly affect the degree of stress evolution because of its islandlike and sporadic formation on the top surface of the Ni_3Sn_4 layer. Isothermal annealing showed that compressive stress, which was induced by the dominant formation of Ni_3Sn_4, developed after an initial evolution of tensile stress.