Analysis and optimization of a power distribution network in 2.5D IC with glass interposer

2.5D integration based on interposer technologies provides high density integration and high system bandwidth. Among many materials for the interposer substrate, glass could be a promising material since it provides low signal loss and its ultra-thin thickness. When chips are stacked on the glass interposer, power distribution network impedance of 2.5D IC must be estimated, analyzed and optimized since it directly affects chips performance and signal integrity. In this paper, we modeled 2.5D-power distribution network using a segmentation method and verified with 3D-EM simulation. With verified model, power distribution network impedance of 2.5D IC with glass interposer was estimated and analyzed. Also modeled 2.5D-power distribution network was optimized with decoupling capacitors. Optimization was based on the target impedance derived from the current spectrum of switching I/O. Target impedance based on the current spectrum allowed more flexible power distribution network design compared to the conventional target impedance.