Misorientation-driven rotation mechanisms of the Cu nanoparticle with substrate during sintering: A molecular dynamics study

Y Shu and H Wan and H Cao and CQ Gui and Y Zhang and RQ Cheng, MATERIALS SCIENCE IN SEMICONDUCTOR PROCESSING, 200, 109927 (2025).

DOI: 10.1016/j.mssp.2025.109927

Copper (Cu) nanoparticle sintering technology is recognized as a promising approach for achieving low-temperature interconnections in advanced materials. However, the rotational behavior of Cu nanoparticles on substrates during the sintering process remains poorly understood. This study employs molecular dynamics simulations to investigate the misorientation-driven rotation mechanisms of Cu nanoparticles during sintering, focusing on the effects of initial misorientation angles, temperatures, and nanoparticle sizes. The results reveal that Cu nanoparticles tend to rotate at the smallest possible angle to align with the substrate's crystallographic orientation. The rotational behavior exhibits central symmetry around an initial misorientation angle of 45 degrees. Stress heterogeneity at the sintering neck initiates dislocation motion, which facilitates rotation and minimizes the system's energy. Both thermal and size effects significantly influence rotation behavior, with non-isothermal sintering proving more effective than isothermal processes, and smaller particles showing faster reorientation than larger ones. This study provides valuable insights into the sintering mechanisms of metal nanoparticles and offers guidance for optimizing low-temperature interconnection processes.

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