Method for estimating the early failure rate of semiconductor devices

According to one embodiment of the invention, a method for estimating the failure rate of semiconductor devices includes obtaining accelerated stress duration data for a plurality of semiconductor devices, determining which of the semiconductor devices fail, classifying the defects for the failed semiconductor devices, determining a distribution model for the accelerated stress duration data, determining a set of parameters for the distribution model, determining a relative proportion of each defect classification to the total number of defect classifications, determining temperature and voltage acceleration factors for each defect classification, identifying actual operating conditions for the semiconductor devices, comparing the actual operating conditions for the semiconductor device with the distribution model, and determining a defect ratio for the semiconductor devices at the actual operating conditions for a predetermined time period based on the comparison.