Embedded SRAM Bitmapping and Failure Analysis for Manufacturing Yield Improvement

SRAM bitmapping and failure analysis have been used as a driver for continuous yield improvement during pre-qualification manufacturing of a microcontroller. The combination of the embedded SRAM electrical failure data and failure analysis results was used to generate a pareto of failure modes and failure mechanisms and establish a correlation between the two. Bitmap trend charts can be used as a manufacturing line monitoring tool to supplement traditional in-line inspection. Identification of manufacturing issues can be obtained from bit failure information and compared with in-line inspection results to quickly identify which specific process module is responsible for a significant yield loss.