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一、引言由于在金属中加上电流应力而使金属原子迁移的现象称为电迁移。最近对薄膜迁移的研究甚多,而且正在改进。然而随着器件性能的提高和小型化的要求,这种迁移现象已成为不能忽视的。再者,金属和硅或二氧化硅,与PSG的反应也成为使器件退化的原因之一。二、质量束流的概念 N=N_oexp(-E_a/kT) N为在常温下金属原子处于激励状态的数目。当金属上加上电流应力时,电子与原子碰撞,使原子沿着电子流的方向流动。此时原子虽也受到电场的反向作用力qZE(Z即原子的带电数),然而它比电子方向的力要小。因而原子受到两个方向的力之和如下式所示:
I. INTRODUCTION The phenomenon of metal atoms migrating due to the addition of current stress in the metal is called electromigration. There has been a lot of research on thin film migration recently and it is improving. However, with the enhancement of device performance and the requirement of miniaturization, such a phenomenon of migration has become an issue that can not be neglected. Furthermore, the reaction of metals with silicon or silicon dioxide with PSG has also been one of the causes of device degradation. Second, the concept of mass beam N = N_oexp (-E_a / kT) N is the number of excited atoms in the metal at room temperature. When a metal is subjected to a current stress, the electrons collide with the atoms, causing the atoms to flow in the direction of the electron flow. At this time, although the atom is also affected by the reverse force of the electric field qZE (Z is the number of charged atoms), however, it is smaller than the force in the electron direction. Thus the sum of the forces exerted by the atoms in two directions is given by: