Mechanics and thermal behavior of Cu-Sn solder reinforced by skeleton intermetallic compounds: Insights from molecular dynamics and experiments

HB Li and KX Shang and J Shen and DJ Luo and Q Chen, MATERIALS TODAY COMMUNICATIONS, 49, 114065 (2025).

DOI: 10.1016/j.mtcomm.2025.114065

Ensuring high thermal and mechanical performance is vital for electronic packaging in wide-bandgap semiconductor devices. This study proposes a Cu-Sn-based solder reinforced by a skeleton-like intermetallic compound (IMC) network, formed via transient liquid-phase diffusion bonding. Molecular dynamics simulations and experiments reveal that the IMC skeleton enhances properties by hindering dislocation motion and refining the microstructure. A 30 vol% IMC structure improves thermal conductivity by 3.56 times compared to pure Sn. Experimentally, the 20 wt% Cu solder joint shows the highest shear strength of 38.75 MPa, while 10 wt% Cu achieves the highest thermal conductivity of 163.68 W/m & sdot;K. Moreover, joints with >= 20 wt% Cu maintain structural integrity at 300 degrees C, indicating strong high-temperature reliability. These findings provide both theoretical insights and practical guidance for designing high-performance, lead-free interconnect materials suitable for next-generation power electronics operating under harsh conditions.

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