Abstract
In recent years, there have been many advances in the equipment and techniques used to isolate faults. There are many options available to the failure analyst. The available techniques fall into the categories of electrical, photonic, thermal and electron/ion beam [1]. Each technique has its advantages and its limitations. In this paper, we introduce a case of successful failure analysis using a combination of several fault localization techniques on a 0.15um CMOS device with seven layers of metal. It includes electrical failure mode characterization, front side photoemission, backside photoemission, Focused Ion Beam (FIB), Scanning Electron Microscope (SEM) and liquid crystal. Electrical characterization along with backside photoemission proved most useful in this case as a poly short problem was found to be causing a charge pump failure. A specific type of layout, often referred to as a hammerhead layout, and the use of Optical Proximity Correction (OPC) contributed to the poly level shorts.
