Various techniques exist for detecting and analyzing defects in products of all kinds. Ideally, every unit produced would be analyzed for defects. Unfortunately, it is often extremely expensive to analyze every single one. Therefore, most defect detection and analysis systems analyze only a sample of all units produced.
As an example, a particular area where defect analysis is very important is the production of integrated circuits. Because of the relatively complex process required to produce and package integrated circuits, opportunities for defects are significant. However, testing of integrated circuits can be very expensive, and thus often only a sampling of the chips are tested.
Within the area of integrated circuit production, significant defect problems arise in connection with bond wires that connect the integrated circuit chip to the pins that allow connection with other circuit components. These bond wires are typically hair-thin conductors, such as gold, copper, aluminum, or other materials. A discontinuity in any of these bond wires can render an integrated circuit completely inoperable, and unless every single chip is tested, most defects will go undetected until the products using them fail.
The need to analyze defects in all units, rather than in just a random sample of units, is particularly apparent for products that will be used in safety-sensitive applications, such as airplanes. For example, the failure of an integrated circuit in a computer-controlled jet aircraft can cause dangerous malfunctions within the aircraft.