I/O Interface Latchup Analysis Using Optical and Electrical Testing

Latchup has long been a concern for CMOS technologies and is becoming more of an issue with the reduction of transistor dimensions and spacing. Although many techniques for avoiding the risk of latchup have been developed, they generally apply to specific technologies and are not portable to others. In light of the problem, IBM engineers conducted an in-depth evaluation of the structures most sensitive to latchup ignition and the many possible triggering mechanisms. In this article, they describe the work they performed along with the findings and provide practical guidelines on how to minimize latchup regardless of the IC technology involved.