Electromigration(EM) failure can be occurred in the via because of the high aspect ratio of Via and the high stress in the via. The theoretical and experimental study is developed in detail. The different via structures are designed and the simulation and accelerate test is operated. The result shows the current density and electric field in the via is decreased apparently and reliability is improved by use the structures, so it is considered of the practical means for improving the copper via interconnect reliability. Finally, two optimized via structures are advanced based on the result of experiments and simulations. The two structures are instructive for the design and manufacture.