Impact of PCB decoupling on device electromigration performance

As power consumption of modern SOC or FPGA devices continues to increase, meeting electro migration (EM) requirement becomes a significant challenge. The required number of I/O and power balls increases as the device performance and power increase. However, the available package balls are limited and the number of ground or power balls is often not increased compared to the device performance causing a major EM bottleneck. To accurately capture the maximum current on package balls, we need to perform EM analysis with the local currents instead of traditional average current which assumes that all balls are electrically tied. To further improve the accuracy of EM analysis, we study the impact of PCB decoupling location to package ball current density for the first time. Our study shows that PCB layout has a big impact on the ball current distribution and the issue needs to be addressed from both design and application perspective.