Accurate Memory Bitmapping based on Built-in Self-Test: Challenges and Solutions

Bitmapping commonly refers to the localization of memory defects prior to physical inspection. With the pervasive use of embedded memories in modern silicon-on-chips (SoC), memory built-in self-tests (MBIST) become the only means to access and evaluate the memory cells. In the event of a failure, the accuracy of defect isolation depends heavily on the quality of MBIST diagnostic to acquire the correct failing details. Although the workflow to enable diagnostic is well established, challenges exist during actual implementations leading to errors in localization. Based upon the authors’ experiences, this paper seeks to highlight possible areas of concern and describe solutions to overcome them.