Mechanism of microweld formation and breakage during Cu-Cu wire bonding investigated by molecular dy

• 作 者: Beikang Gu Shengnan Shen Hui Li
• 机 构: School of Power and Mechanical Engineering,Wuhan University,Wuhan 430072,China;School of Power and M
• 出 处: 中国物理B（英文版）
• 发表日期: 2022年1期
• 关键词: Cu-Cu wire bonding bonding mechanism atomic stress molecular dynamics simulation

Currently,wire bonding is the most popular first-level interconnection technology used between the die and package terminals,but even with its long-term and excessive usage,the mechanism of wire bonding has not been completely eval-uated.Therefore,fundamental research is still needed.In this study,the mechanism of microweld formation and breakage during Cu-Cu wire bonding was investigated by using molecular dynamics simulation.The contact model for the nanoin-dentation process between the wire and substrate was developed to simulate the contact process of the Cu wire and Cu substrate.Elastic contact and plastic instability were investigated through the loading and unloading processes.Moreover,the evolution of the indentation morphology and distributions of the atomic stress were also investigated.It was shown that the loading and unloading curves do not coincide,and the unloading curve exhibited hysteresis.For the substrate,in the loading process,the main force changed from attractive to repulsive.The maximum von Mises stress increased and shifted from the center toward the edge of the contact area.During the unloading process,the main force changed from repulsive to attractive.The Mises stress reduced first and then increased.Stress concentration occurs around dislocations in the middle area of the Cu wire.