Localization of weak heat sources in electronic devices using highly sensitive lock-in thermography

Using lock-in thermography the temperature resolution of a Focal Plane Array (FPA) thermocamera can be improved down to 40 μK after 1000 s measuring time. This allows the detection of even weak heat sources (hot spots) in electronic devices. The technical realization of lock-in thermography is described here with typical applications to the investigations of shunts in solar cells and localization of local heat sources in ICs. Because of its high spatial resolution, its high thermal sensivity as well as its simplicity, this technique is an advantageous alternative to usual thermal testing in electronic devices.