Voltage Contrast Application on 1M SRAM Single Bit Failure Analysis

A single bit failure is the most common and the most difficult failure mode to analyze in a Static Random Access Memory (SRAM). As chip feature sizes decrease, the difficulties compound. Traditional failure analysis techniques are often ineffective, particularly for high temperature operating life (HTOL) failures, because HTOL failures are most often caused by subtle physical defects. A new analysis approach, using Focused Ion Beam (FIB) cross-sectioning combined with FIB passive voltage contrast (PVC), greatly enhances the analysis success rate. In this paper, we outline the use of these new techniques and apply them to a technologically important problem.