A tool for analog/RF BIST evaluation using statistical models of circuit parameters

International audienceTesting analog integrated circuits is expensive in terms of both test equipment and time. To reduce the cost, Design-For-Test techniques (DFT) such as Built-In Self-Test (BIST) have been developed. For a given Circuit Under Test (CUT), the choice of a suitable technique should be made at the design stage as a result of the analysis of test metrics such as test escapes and yield loss. However, it is very hard to carry out this estimation for analog/RF circuits by using fault simulation techniques. Instead, the estimation of parametric test metrics is made possible by Monte Carlo circuit-level simulations and the construction of statistical models. These models represent the output parameter space of the CUT in which the test metrics are defined. In addition, models of the input parameter space may be required to accelerate the simulations and obtain higher confidence in the DFT choices. In this work, we describe a methodological flow for the selection of most adequate statistical models and several techniques that can be used for obtaining these models. Some of these techniques have been integrated into a Computer-Aided Test (CAT) tool for the automation of the process of test metrics estimation. This estimation is illustrated for the case of a BIST solution for CMOS imager pixels that requires the use of advanced statistical modeling techniques