Defect Detection Faces Smaller, Deadlier Hurdles

An endemic disadvantage of smaller nodes has been that, as device architectures shrink, defects and particles on the previous node that were unimportant have the potential to become device killers. This, in turn, has device makers demanding greater capability to detect increasingly smaller defects and particles. Although the race between detection capability and shrinking defects has basically been going on since our industry's beginning, now, and in the not-so-distant future, formidable hurdles in the shape of 3-D architectures and fundamental limits challenge inspection, measurement and test platform technology. Immersion lithography will make life difficult for defect detection. Most new defects are large and generally well understood, such as immersion litho-related ones like bubbles, watermarks, etc." These can be controlled to the same extent as with dry lithography, because their sources are known. Paradoxically, because of immersion lithography's higher resolution, smaller defects are emerging.