Atomistic simulation of mechanical behavior of Cu/Cu3Sn solder interface with Kirkendall void under shear and tensile deformation

• Published in: Applied physics. A, Materials science & processing Materials science & processing, 2023-04, Vol.129 (4), Article 255
• Main Authors: Wu, Cheng-Da, Liu, Kai-Wei, Cheng, Po-Chien
• Format: Article
• Language: English
• Subjects: Applied physics; Characterization and Evaluation of Materials; Collapse; Condensed Matter Physics; Deformation; Deformation effects; Edge dislocations; Machines; Manufacturing; Materials science; Mechanical properties; Molecular dynamics; Nanotechnology; Optical and Electronic Materials; Physics; Physics and Astronomy; Plastic deformation; Processes; Shear bands; Shear stress; Shearing; Simulation; Solders; Surfaces and Interfaces; Tensile deformation; Tensile strain; Tensile strength; Tensile stress; Tensile tests; Thin Films
• ISSN: 0947-8396; 1432-0630
• DOI: 10.1007/s00339-023-06558-5

The effects of a Kirkendall void at the nanoscale on the mechanical behavior of a Cu/Cu 3 Sn solder interface under shear and tensile tests, respectively, are studied using molecular dynamics simulations. The simulation results show that for a solder interface without a Kirkendall void under tension, fracture is induced by a collapse of the interface, and that for a solder interface without a Kirkendall void under shearing, plastic deformation is dominated by shear bands. A shear band propagates through a small void (radius ≤ 3 nm) but is stopped by a large void (radius = 4 nm) or neighboring dislocations. For a solder interface with a Kirkendall void under tension, a collapse of the solder interface occurs faster with increasing void radius. When the void is far away from the solder interface, fracture is dominated by a competition between a collapse of the solder interface and void deformation and growth. A solder interface has the maximum shear and tensile strength when a pre-existing void (radius = 1 nm) locates at the interface. For a solder interface with a Kirkendall void, the ultimate shear stress, tensile stress, and tensile strain decrease with increasing initial void radius.