Failure analysts occasionally find themselves faced with the problem of having one of the various defect isolation techniques indicating a defect location, and yet no defect is readily visible through the various imaging methods available. Many common conventional imaging tools, such as scanning electron microscopes (SEM), display images in shades of gray. The human eye is inherently more sensitive to changes in color rather than changes in grayscale. As a result, subtle variations in grayscale which could indicate the defect location can go unobserved unless a careful examination of the image intensities is performed. One useful way to highlight these variations is through intensity profiling where a line scan is drawn through the region under investigation and compared to an identical reference location contained within the same image. Subtle variations in the intensity profiles can then be identified and defect locations can be pinpointed to specific locations for later cross sectioning and final root cause determination. This paper discusses the application of this methodology to two case studies: a resistive short and a resistive open.

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