Magnetic Microscopy is a non-destructive contactless technique for defect localization.
When a current flows inside a conductor, it generates a magnetic field. By measuring the field, it is possible to reconstruct the path followed by the currents, and consequently localize any defects. The tool used is a Neocera MAGMA C20, which is equipped with a SQUID, the most sensitive magnetic sensor currently available. Thanks to its high sensitivity, it is possible to generate a map of very weak currents at long distances.
Magnetic Microscopy has many advantages over other Failure Analysis techniques. As the magnetic field is not perturbed by non-ferromagnetic materials, such as those commonly used in the semiconductor industry, we can produce a map of the currents without de-processing the device. There is therefore no risk of losing the defect by de-packaging the component in the localization stage. The Magnetic Microscopy imaging technique is also strongly linked to the electrical behaviour of the device, so the exact location of the electrical failure can be identified. Finally, at Intraspec Technologies we have developed the technique so that we can also reconstruct the current paths, and hence localize defects in 3D components.