The SEM as a Defect Analysis Tool for Semiconductor Memories

Defect and failure analysis of semiconductor memories is discussed, with emphasis on the use of the SEM in the voltage contrast mode as an analysis tool. The 4100, a 256 bit bipolar memory, was chosen as a vehicle for this study. Voltage contrast micrographs of defects and cell operation in this die demonstrate the usefulness of this technique for quickly locating and analyzing failures in large ordered memory arrays. Voltage contrast micrographs of the 4102, a 16 bit associative memory, are included to demonstrate extension of the technique to multi-level metallization structures.