Correlation of gate oxide reliability and product tests on leading edge DRAM technology

摘要

A detailed comparison between lifetime predictions from reliability measurements and the failure rates in standard product tests was done to verify existing reliability methods and justify the use of scribe line test structures to evaluate the actual product lifetimes. Two independent sets of samples were studied by high constant voltage stress of multi transistor test structures in the scribe line and by HTOL test, which stresses directly the gate oxide of the product at voltages close to use conditions. A detailed analysis of the resulting failure distributions yielded very good agreement between the two tests and confirmed the validity of the lifetime predictions of the reliability assessment.