Sources of variation in piezoresistive stress sensor measurements

Piezoresistive stress sensors are widely used to characterize semiconductor die stresses. Packaging stresses induce a small change in resistance in the sensors and they are highly sensitive to factors such as temperature and processing conditions. Thus, accurate stress prediction requires calibration and knowledge of all sources of variation in the resistance response of the sensors. This paper quantifies the effect of process variations and demonstrates that die level tracability is critical to ensure accurate stress prediction.