The characterisation of diffusion soldered Cu/In/Cu interconnections is presented in this work. The main feature of

S. SOMMADOSSI, W. GUST AND E. J. MITTEMEIJER

MATERIALS SCIENCE AND TECHNOLOGY

Año: 2003 vol. 19 p. 528 - 534

0267-0836

The characterisation of diffusion soldered Cu/In/Cu interconnections is presented in this work. The main feature of this joining process is the production of a bond at a low fabrication temperature, which allows high service temperatures. The interconnection is formed entirely by intermetallic phases (IPs) which form isothermally first by a liquid – solid reaction and then by a solid – solid reaction. The morphology and the growth kinetics of the IPs formed in the interconnection zone at temperatures in the range 180 – 430°C were examined by electron probe microanalysis, X-ray diffraction and transmission electron diffraction analysis. In accordance with the phase diagram, the phases Cu11In9, Cu2In and Cu7In3 (at T<310°C) and Cu2In and Cu7In3 (at T>310°C) appeared in the interconnection zone. The thickness of the IPs formed during the solid – solid reaction obeyed a parabolic growth law. The growth rate constants were calculated for the Cu2In and Cu7In3 phases. Using these values and the equilibrium concentration of the IPs, the integral interdiffusion coefficients were calculated through Wagner’s approach.