TDDB Data Generation for Fast Lifetime Projections Based on V-Ramp Stress Data

Reduced failure rates required by the industry lead to increased costs and time loss for the chip manufacturer since the efforts for continuous process improvements, qualification, screening, and increased test coverage are generally not paid by the customer. However, related costs can be reduced by improved/accelerated reliability testing methods and an approach to a knowledge-based and application-specific qualification and process monitoring strategy. One example of saving time (and costs) during gate oxide reliability testing is given in this paper, showing that time-dependent dielectric breakdown (TDDB) data for lifetime extrapolation and quality assessment can be generated from linear ramped voltage test (RVT) data with high accuracy. Given the parameter of the RVT stress profile, the concept of equivalence is successfully applied to convert stress time data at each ramp stress level to corresponding accumulated equivalent ages at any one stress level. Taking into account these ages until breakdown, failure probabilities with the model parameters of the stress-life relationship being the only fitting parameters can directly be computed and converted to TDDB failure distributions.