Evaluation of the impact of mechanical stress on CMOS device mismatch

Mechanical stress occurs during packaging and front-end processing. The impact of mechanical stress on device mismatch is investigated. A measurement set-up is presented which uses a beam bending technique to apply mechanical stress. The characterization of mismatch is based on a test macro for the extraction of pair mismatch and long distance mismatch. It is found that the device characteristics change when stress is applied dependent on the device orientation with respect to the stress direction. 0.18 /spl mu/m, 0.25 /spl mu/m, and 0.50 /spl mu/m technologies are investigated. No major impact is observed on the pair-mismatch of directly neighboring devices and on the long distance mismatch due to mechanical stress.