金属互连电迁移噪声的分形特征

为了研究金属互连电迁移失效机理并寻找新的电迁移表征参量，应用分形理论，通过电子扩散轨迹分形维数，将电迁移噪声时间序列分形维数与晶粒间界分形维数相联系，确定了噪声时间序列分形维数在电迁移演变中的变化趋势.研究结果表明，在金属互连电迁移前期，晶粒间界形貌越来越复杂，致使噪声时间序列的分形维数逐渐增大；成核后，由于空位凝聚成空洞，晶粒间界形貌变得较成核前规则，致使噪声时间序列的分形维数减小；成核时刻是其折点.实验结果证明理论分析的正确性，噪声时间序列的分形维数可望作为金属互连电迁演变的表征参量.

Fractal character of noise in electromigration in metel interconnection

Based on fractal theory , through the fractal dimension of electro-diffusion, the dimensions of noise time series and grain boundary are corelated. The change of noise dimension is shown to be useful for studying the damage mechanism and determining the parameters for electromigration. The picture of grain boundary becomes complicated in the early period of electromigration, but after the voids are informed, it becomes more regular. So the fractal dimension of time series increases during the early stage of electromigration and goes down after the voids are informed. The theoretical analysis is confirmed by experiment, the dimension of noise time series may be a new characteristic parameter for metallic interconnection electromigration.