Reliability evaluation of a flash RAM using step-stress test results

This paper presents a reliability evaluation on an ASIC (application specific integrated circuit) flash RAM using an accelerated life test. The accelerated stress applied on the life test is a combination of temperature and humidity using a step-stress profile. Reliability assessment is conducted by using the Peck combination model to quantify the acceleration factors, and convert the operation cycles at various high temperature and humidity conditions to the equivalent cycles at normal operation condition. The Weibull analysis is also conducted based on the cumulative equivalent test time for each PCB. Mean time to failure (MTTF) and the cumulative failure probabilities were calculated for one-year operation, five-year operation, and the 40000 power on- and-off cycles of design specification. The technique of the accelerated life test and reliability assessment presented in this paper can be used in other similar programs and reliability assessment.