1. A method of forming a device comprising: providing a substrate containing at least a partially formed device thereon, wherein the device comprises at least one defect site; acquiring a pixilated image of the defect site selected, wherein each pixel comprises a grey level value (GLV); eliminating surrounding noises of the defect site; identifying a point of the image as the center of the defect; performing a plurality of iterations to exclude outer edge pixels surrounding the center of the defect image; and categorizing the defect as a killer defect or a non-killer defect.