三维封装电迁移Cu互连线的多物理场模拟仿真

With the development of three-dimensional package interconnects decreasing their sizes into sub-micro levels, problems such as high current density, high-stress, and difficulty heat dissipation have become more and more serious. The phenomenon of atomic-scale migration fai-lure has gradually become a reliability problem that cannot be ignored in VLSI. Copper has a lower resistivity than aluminum and has better electromigration resistance. It is a new generation of reliable interconnect material, but there are still insufficient studies on atomic migration of copper interconnects. The present analytical mode of the electromigration reliability is mainly aimed at the single metal wire at a constant temperature. Although this method is relatively simple to calculate, it has little significance for the guiding of the actual situation. The main reasons are as follows: 1. It is the temperature gradient that exists in high-density integrated circuits in reliability. 2. The three-dimensional structure of the interconnection line has an important influence on the distribution of the temperature and electrical current of the interconnect. These parameters seriously affect the electromigration resistance of metal atoms. This work proposes a new modeling method of electromigration simulation, and establishes a classic three-dimensional Cu interconnect structure through COMSOL multiphysics software. The temperature, current density and stress distribution by a finite element simulation were carried out and better data simulation results were obtained. The results show that the current in the metal interconnection has serious siltation phenomenon on the inner side of the right angle, and the electromigration is most intense at the turning point of the interconnection line; the high temperature area is located between the inner and outer sides of the right angle, and the degree of thermal migration increases with the increase of temperature; the high-stress area is mainly at the outer edge of the interconnection line, but the stress migration accounts for a relatively small proportion of the overall electromigration, which can be ignored. In addition, the electromigration resistance of Cu is generally better than that of Ag, as Cu is an exceptional high-density integrated circuit conductor material.