Phase Equilibria of the Sn–Ni–Si Ternary System and Interfacial Reactions in Sn–(Cu)/Ni–Si Couples
- First Online:
Interfacial reactions in Sn/Ni–4.5 wt.%Si and Sn–Cu/Ni–4.5 wt.%Si couples at 250°C, and Sn–Ni–Si ternary phase equilibria at 250°C were investigated in this study. Ni–Si alloys, which are nonmagnetic, can be regarded as a diffusion barrier layer material in flip chip packaging. Solder/Ni–4.5 wt.%Si interfacial reactions are crucial to the reliability of soldered joints. Phase equilibria information is essential for development of solder/Ni–Si materials. No ternary compound is present in the Sn–Ni–Si ternary system at 250°C. Extended solubility of Si in the phases Ni3Sn2 and Ni3Sn is 3.8 and 6.1 at.%, respectively. As more Si dissolves in these phases their lattice constants decrease. No noticeable ternary solubility is observed for the other intermetallics. Interfacial reactions in solder/Ni–4.5 wt.%Si are similar to those for solder/Ni. Si does not alter the reaction phases. No Si solubility in the reaction phases was detected, although rates of growth of the reaction phases were reduced. Because the alloy Ni–4.5 wt.%Si reacts more slowly with solders than pure Ni, the Ni–4.5 wt.%Si alloy could be a potential new diffusion barrier layer material for flip chip packaging.
KeywordsSn–Ni–Si phase equilibria flip chip packaging
Unable to display preview. Download preview PDF.
- 1.J.H. Lau, Flip Chip Technologies (New York: McGraw-Hill, 1996), pp. 25–59.Google Scholar
- 10.M. Hansen, in Constitution of Binary Alloys, McGraw-Hill, NewYork, 1959, 1965, 1969.Google Scholar
- 12.P. Nash and A. Nash, Binary Alloy Phase Diagrams, 2nd ed., Vol. 3, ed. B. Thaddeus and Massalski (Materials Park: ASM International, 1991), p. 2859.Google Scholar
- 17.R.W. Olesinski and G.J. Abbaschian, Binary Alloy Phase Diagrams, 2nd ed., Vol. 3, ed. B. Thaddeus and Massalski (Materials Park: ASM International, 1984), pp. 3361–3362.Google Scholar
- 22.JCPDS # 65-1315.Google Scholar
- 23.JCPDS # 65-3521.Google Scholar