Many defects in ICs generate excessive heat during operation due to the power dissipation associated with the excess current flow at the defect site. Several thermal detection techniques have been used for failure analysis:
         i) liquid-crystal imaging, which relies on the presence of a thermal sensing film placed on the sample to provide an evidence of thermal activity.
         ii) fluorescent microthermal imaging (FMI). Similar to liquid-crystal imaging, this method also relies on the presence of a thermal sensing film placed on the sample.
         iii) infrared (IR) thermography, which is a non-contact thermal mapping technique.

Based on blackbody theory, Figure 4910 (a) shows that even for objects at 2000 K, there is only a small portion of the radiated energy in the visible portion of the spectrum. The majority of the information relating to the object's temperature is well into the infrared region. In the semiconductor industry, only few devices operate at such high temperatures. Figure 4910 (b) shows the temperatures around and slightly above room temperature with the particular interest between 300 and 350 K. It is clear that most of the energy is emitted at wavelengths greater than 5 µm, which is in the infrared region. Then, for such thermal analysis, the detector needs to be sensitive well into the infrared range.

(a)	(b)

[1] Paiboon Tangyunyong and Christian Schmidt, Thermal Defect Detection Techniques, Sandia National Laboratories is a multimission laboratory managed and operated by National Technology & Engineering Solutions of Sandia, LLC, a wholly owned subsidiary of Honeywell International Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525.