微型化器件中多晶Cu晶向排布对其受压力学特性的影响仿真研究

Simulation on influence of crystal orientation arrangement of polycrystalline Cu on its compressive mechanical properties in miniaturized devices

为系统研究多晶Cu材料晶向排布对其受压力学特性的影响,通过采用晶体塑性有限元的方法模拟了不同晶向Cu的纳米压痕试验过程.仿真结果表明,从受力变形特点来看,当载荷为几何对称压入时,对称于压入面的两对滑移系呈现对称滑移,对应于各个方向的滑移系产生的塑性变形也呈现对称分布;当压入模式为非对称压入时,不同滑移面的各个滑移系产生的塑性应变均不对称;从受力响应来看,压入方向越趋向于垂直于密排面{111},压入载荷水平越高,在压入深度从100 nm增加至500 nm过程中,伴随压入方向与密排面夹角从0°增加至54.732°,压入载荷从5.090 mN增加至5.674 mN.上述结论对Cu晶向择优和微互连设计具有重要的指导意义,有利于微互连结构可靠性的提升.

The nanoindentation test of Cu with different crystal orientations was simulated by the crystal plastic finite element method to systematically study the influence of the crystal orientation arrangement of Cu on its compressive mechanical properties.The simulation results show that there is a significant correlation between compressive mechanical properties and crystal orientation of Cu.When the press-in mode is symmetric,the two pairs of slip systems symmetrical to the press-in surface show symmetrical slip,and the plastic deformation corresponding to the slip systems in all directions also shows symmetrical distribution.When the press-in mode is asymmetric,the plastic strain produced by each slip system of different slip surfaces is asymmetric.In addition,with the press-in direction tending to be perpendicular to the dense packing surface{111},the press-in load gradually increases.With the increase of the press-in depth from 100 nm to 500 nm,the angle between the press-in direction and the dense surface increases from 0°to 54.732°,and the press-in load increases from 5.090 mN to 5.674 mN.The result is instructive for the selection of Cu crystal orientation and the design of the micro-interconnection,which is beneficial for the improvement of the reliability of the micro-interconnection.