Al-Cu wafer-level bonding microscopic mechanism and its strength study

YQ Ren and YX Wang and BH Lin and HY Li and ZK Wang and BQ Xu and QW Xu and YP Zheng and ZJ Qi and W Shen and Y Liu and Y Cai and CL Sun, JAPANESE JOURNAL OF APPLIED PHYSICS, 64, 065503 (2025).

DOI: 10.35848/1347-4065/adde06

Aluminum-copper (Al-Cu) wafer-level bonding technology is an essential process in the micro-nano manufacturing of electronic packaging; however, research is scarce on the micro-mechanisms of Al-Cu bonding. This paper uses molecular dynamics simulations and experimental methods to study the atomic diffusion behavior, bonding interface, and bonding strength of Al-Cu wafer-level bonding. The results indicate that increasing the bonding temperature from 700 to 750 K facilitates adequate atomic diffusion, leading to intimate contact at the bonding interface and a significant increase in the thickness of the transition layer, with the bonding strength exceeding 71.7 MPa. The microscopic deformation mechanism of Al-Cu bonded specimens during the tensile process was analyzed. In this study, high-strength Al-Cu wafer-level bonding samples were successfully prepared, and the bonding quality was significantly improved.

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