Phase Equilibria of the Sn-Ag-Cu-Ni Quaternary System at the Sn-Rich Corner

Authors: Chen, Sinn-Wen; Chang, Cheng-An

Source: Journal of Electronic Materials, Volume 33, Number 10, 1 October 2004 , pp. 1071-1079(9)

Publisher: Springer

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Abstract:

Knowledge of phase equilibria of the Sn-Ag-Cu-Ni quaternary system at the Sn-rich corner is important for the understanding of the interfacial reactions at the Sn-Ag-Cu/Ni contacts, which are frequently encountered in recent microelectronic products. Various Sn-Ag-Cu-Ni alloys were prepared and equilibrated at 250°C. The alloys were then quenched and analyzed. The phases were determined by metallography, compositional analysis, and x-ray diffraction (XRD) analysis. No quaternary phases were found. The isoplethal sections at 60at.%Sn, 70at.%Sn, 80at.%Sn, and 90at.%Sn at 250°C are determined. The phase equilibrium relationship was proposed based on the quaternary experimental results and the 250°C isothermal sections of the four constituent ternary systems, Sn-Ag-Cu, Sn-Ag-Ni, Sn-Cu-Ni, and Cu-Ag-Ni. Because there are no ternary phases in all these three systems, all the compounds are in fact binary compounds with various solubilities of the other two elements.

Keywords: PB-FREE SOLDERS; PHASE EQUILIBRIUM; SN-AG-CU-NI

Document Type: Research article

Publication date: 2004-10-01