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 into embedded RAMs, currently under evaluation within STMicroelectronics. The proposed scheme uses dedicated circuitry embedded in a BIST wrapper, and an ATE test program to schedule the data extraction flow and to analyze the gathered information. Testing is performed exploiting a standard IEEE 1149.1 TAP, which allows the access to multiple memory cores with a P1500 compliant solution. The approach aims at implementing a low-cost solution to diagnose embedded RAMs with the goal to minimize the ATE costs and the time required to extract the diagnostic information. In our approach, the ATE drives the diagnostic scheme and performs the classification of faults, allowing the adoption of low-cost equipments. The proposed solution allows a scalable extraction of test data, whose amount is proportional to the available testing time. In order to accelerate fault classification, image processing techniques have been applied. The Hough transform has been adopted to analyze the bitmap representing the faulty cells. Experimental results show the advantages of the proposed approach in terms of time required to complete the diagnostic process.