Mound defect modeling in yield forecasts

Although the majority of defects found in manufacturing lines have predominantly two-dimensional effects, there are many situations in which 2-D defect models do not suffice, e.g., tall layer bulks, residual resist flakes, and extraneous materials embedded in the IC. In this paper a more general model based on mound defects is presented. Both catastrophic and soft effects of mound defects are investigated. The defect model is based on the geometrical properties that result from the interaction between IC and defect size in two coordinate spaces: x-y and z. The approach to model catastrophic effects is a natural extension to the concept of critical areas, namely, the extraction of critical volumes. The simplicity of the extraction method makes it suitable for inclusion in common layout editing tools. Through the course of this work hints to the origins of mound defects will be given, conditions to capture critical volumes will be developed, realistic layout results will be shown, and a yield model taking into account these new kind of defects will be presented