Section 3: Fault Isolation
In this overview of diagnosis of scan logic and diagnosis driven failure analysis, the authors explore the world of diagnosis of digital semiconductors devices. After shortly outlining the technology behind diagnosis, the main part of this article describes key improvements to the basic diagnosis tools, discussing their merits for the failure analysis engineer. The article also describes the various requirements and other considerations that typically need to be taken into account to set up a full working scan diagnosis system. It summarizes the principles of design with embedded compression technologies. Finally, several successful industrial applications of diagnosis are presented.
Magnetic field imaging (MFI), generally understood as mapping the magnetic field of a region or object of interest using magnetic sensors, has been used for fault isolation (FI) in microelectronic circuit failure analysis for almost two decades. Developments in 3D magnetic field analysis have proven the validity of using MFI for 3D FI and 3D current mapping. This article briefly discusses the fundamentals of the technique, paying special attention to critical capabilities like sensitivity and resolution, limitations of the standard technique, sensor requirements and, in particular, the solution to the 3D problem, along with examples of its application to real failures in devices.