Atomistic Investigation on the Fracture Property Relationships in Copper/Double-Walled Carbon Nanotubes Composites for Application in Through Silicon Via

초록

Copper-carbon nanotube composites have attracted increasing interest for application in through silicon vias, a semiconductor packaging technology, due to their synergistic properties. In this study, in order to contribute to the conservative design of copper/carbon nanotube-based materials for semiconductor packaging applications, atomistic simulations were performed to conduct tensile tests on a half-cracked copper composite reinforced with double-walled carbon nanotubes. Double-walled carbon nanotubes of varying chiralities were embedded within the copper matrix to examine the influence of nanotube structure on mechanical performance. Stress-strain responses and effective Young's moduli of the composites were quantified and compared with predictions from the rule of mixtures. Results indicate that the incorporation of double-walled carbon nanotubes effectively delays crack propagation, highlighting the reinforcing role of nanoscale inclusions. Fracture-related properties were further evaluated through surface energy calculations, estimating fracture toughness and failure strength using the Griffith energy balance. These estimates were validated against failure strengths derived from direct stress-strain measurements. Critical energy release rates in the vicinity of the double-walled carbon nanotubes were determined via a two-specimen approach, with the atomic cross-section approximated as a rectangular continuum for quantitative analysis. The resulting surface energies and energy release rates of both the nanocomposites and individual constituents partially conformed to the rule of mixtures. These findings provide atomistic insights into the conservative mechanical design of copper/double-walled carbon nanotube nanocomposites, offering a perspective to enhanced fracture resistance and reliability in three-dimensional semiconductor interconnecting architectures.

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