关键词: 热机械应力, 有限元分析, 可靠性优化

Abstract: This study employed finite element simulation to establish a thermo-mechanical coupling model, systematically examining the effects of ceramic substrate material, pad geometric parameters, lead layout, copper cladding distribution, and substrate thickness on the stress at the capacitor soldering root. The results indicate that the key factor leading to the 56.8% increase (178.9 MPa) in stress at the capacitor soldering root on the AlN-AMB substrate is the significant 104.5% difference in the coefficient of thermal expansion (CTE) between AlN ceramic (CTE=4.4×10^-6/K) and the BaTiO₃ capacitor (CTE~9.0×10^-6/K), compared to Al₂O₃-DBC substrates (CTE=7.0×10^-6/K). By optimizing the capacitor pad size, the optimal design parameters determined in this study reduced the stress at the capacitor root by 40.5% (to 106.5 MPa). Furthermore, through rational layout of the conductors and the positional relationship of the copper-clad areas, the stress on the capacitor root can be further effectively reduced. The reliability prediction model established in this study provides a theoretical basis for the design of AlN copper-clad substrates for high-reliability hybrid integrated circuit substrates.

Key words: thermo-mechanical stress, finite element analysis, reliability optimization