Current Density Calculation Using Rectilinear Region Splitting Algorithm for Very Large Scale Integration Metal Migration Analysis.

摘要

In Very Large Scale Integration (VLSI) chips, metal migration(MM) is an important problem from the reliability standpoint. Furthermore, as the feature size is scaled down, MM becomes an even greater problem because of the higher current densities that would exist in the power and ground busses. Because of the complexity of VLSI power busses, there exists a need for a computer-aided design tool to correctly predict the likely failure site(s). This thesis deals with a primitive splitting algorithm that calculates current density waveforms efficiently. These waveforms are used to find the Median Time to Failure (MTF), a major parameter of concern in predicting MM. This algorithm has been motivated by examining the equipotential plots obtained through finite-element method analysis of simple regions. It has been successfully implemented and tested, and some examples are described. Keywords: Metal migration; Electromigration; Current density calculation; Power bus modeling. (JHD)