Generation of electromigration ground rules utilizing Monte Carlo simulation methods

A novel method is presented for determining ground rule limits for the maximum current allowed in a metal line based on the electromigration and process parameters. A Monte Carlo technique is utilized to simulate the distribution of metal width, metal thickness, and electromigration properties to determine the maximum current allowed for a given failure criterion. In linewidths of less than 6 μm, the Monte Carlo method doubles the allowed current compared to the worst-case linewidth approach. Thus, increased currents are allowed in metal lines without sacrificing predetermined reliability goals. It is also demonstrated that the accuracy of the Monte Carlo simulation is based on the number of iterations executed. Specifically, it is shown that the accuracy of the simulation is dependent on the number of outer loop iterations performed