A BIST-based solution for the diagnosis of embedded memories adopting image processing techniques

This paper proposes a new solution for the diagnosis of faults in embedded RAMs, currently under evaluation within STMicroelectronics. The proposed scheme uses dedicated circuitry added to the BIST selecting the failure data, and the ATE test program to schedule the data extraction flow. Testing is possible through a standard IEEE 1149.1 TAP, and allows the access to multiple cores with a P1500 compliant solution. The approach aims at implementing a low-cost solution to diagnose embedded RAMs with the goal of minimizing the ATE costs and the time required to extract the diagnostic information. In our approach, the ATE drives the diagnostic scheme and is dedicated to the classification of faults, only, allowing adopting low-cost equipment. The proposed solution allows a scalable extraction of test data, whose amount is proportional to the available testing time. In order to accelerate the fault classification, image processing techniques have been applied The Hough transform has been adopted to analyze the bitmap representing the faulty cells. Preliminary experimental results show the advantages of the proposed approach in terms of time required to complete a diagnostic process.