The thermal stress in metal conductor layers strongly influences the reliability of high-power electrical modules. We evaluated the stress behavior of copper paste films, which were sintered on alumina substrates, during repeated thermal cycles. The thermal cycle tests were performed from room temperature to 500 °C, which was lower than the sintering temperature. As the number of cycles increased, there was an increase in the temperature at which the compressive stress reached a maximum during heating and there was an increase in the tensile stress during cooling. However, the magnitude of increase reduced as the number of thermal cycles increased. On the other hand, the stress-change rates in the elastic region remained unchanged though the films were subjected to the thermal cycles. We surmised that these changes were owing to an increase in the dislocation density due to plastic deformation, grain refinement due to the increase in the dislocation density, and restoration processes in the copper paste films.
Thermal Stress Dislocation Density Sinter Temperature Thermal Cycle Creep Deformation
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This work was supported by Council for Science, Technology and Innovation (CSTI), Cross-ministerial Strategic Innovation Promotion Program (SIP), “Next-generation power electronics/Consistent R&D of next-generation SiC power electronics” (funding agency: NEDO).
M. Yamagiwa, Packaging technologies of power module for hybrid electric vehicles and electric vehicles (recent developments and future issues). Ceram. Jpn. 45, 432 (2010). (in Japanese)Google Scholar
S. Fukuda, K. Shimada, N. Izu, W. Shin, K. Hirao, M. Sandou, N. Murayama, Residual stress in copper paste films on alumina substrates. J. Mater. Sci. Mater. Electron. 26, 4823 (2015)CrossRefGoogle Scholar
T.-Y.J. Hsu, Z. Wang, Cyclic stress–strain response and microstructure evolution of polycrystalline Cu under pure compressive cyclic loading condition. Mater. Sci. Eng. A 615, 302 (2014)CrossRefGoogle Scholar
P.A. Flinn, D.S. Gardner, W.D. Nix, Measurement and interpretation of stress in aluminum-based metallization as a function of thermal history. IEEE Trans. Electron Devices 34, 689 (1987)CrossRefGoogle Scholar
G.G. Stoney, The tension of metallic films deposited by electrolysis. Proc. R. Soc. Lond. A 82, 172 (1909)CrossRefGoogle Scholar
J. Jiang, T.B. Britton, A.J. Wilkinson, Evolution of intragranular stresses and dislocation densities during cyclic deformation of polycrystalline copper. Acta Mater. 94, 193 (2015)CrossRefGoogle Scholar
T. Hasegawa, S. Karashima, Y. Ikeuchi, High-temperature creep rate and dislocation structure in a dilute copper-aluminium alloy. Acta Metal. 21, 887 (1973)CrossRefGoogle Scholar
M.D. Thouless, J. Gupta, J.M.E. Harper, Stress development and relaxation in copper films during thermal cycling. J. Mater. Res. 8, 1845 (1993)CrossRefGoogle Scholar
T. Onishi, H. Fujii, T. Yoshikawa, J. Munemasa, T. Inoue, A. Miyagaki, Effects of the high-pressure annealing process on the reflow phenomenon of copper interconnections for large scale integrated circuits. Thin Solid Films 425, 265 (2003)CrossRefGoogle Scholar
T. Kajiura, M. Tsukamoto, A. Yamamoto, Recovery and recrystallization processes in oxygen-free copper after cold-rolling. J. Jpn. Inst. Metals Mater. 78, 126 (2014). (in Japanese)CrossRefGoogle Scholar
S. Kuroda, T.W. Clyne, The quenching stress in thermally sprayed coatings. Thin Solid Films 200, 49 (1991)CrossRefGoogle Scholar