Electrical characterization of multi-layer BGA packages for high speed, high switching activity applications

With ever-increasing requirement for package performance, multi-layer BGA packages are gradually moving into mainstream. This trend represents a major challenge in package characterization because of the difficulty in modeling the complex interaction between signal traces and power/ground planes in a multi-layer package. An accurate package model encompassing both signal and power/ground is especially critical for performance evaluation in applications where a large number (hundreds) of output drivers switch simultaneously at high speed (over 200 MHz clock speed). There thus exists a need for a novel approach to create models for multi-layer packages with acceptable accuracies to predict their performance in high end applications, and yet with reasonable complexities not to overwhelm the model parameter extraction and subsequently the simulation software. This paper presents results of simulations to evaluate performance of a multi-layer BGA package in a high speed, high switching activity application. Different modeling methodologies and model circuit topologies are employed to generate models with different complexities and accuracies. The major difference between these models would be in the amount of embedded inductive coupling information. These models are then used in system simulations to generate different performance parameters for comparison of accuracy. The die power/ground bus model and the package model are altered to evaluate different schemes to enhance system performance