Dynamic and static thermal study of micromachined heaters: the advantages of visible and near-infrared thermography compared to classical methods

We report on the dynamic and static thermal characterization of microsystems using a visible and near-infrared (NIR) thermography system based on a low-cost standard CCD sensor. The interest of this method is that it is possible to obtain a true spatial resolution better than 500 nm, which is necessary in high spatial resolution applications (microsystem applications). Another interesting point of this optical method is that the temperature error versus the emissivity error is always very low (compared to infrared thermography). We show, in this study, that this behavior originates in the high sensitivity of Planck's law in this wavelength range (compared to infrared range). Thus, we demonstrate the principal advantages of this method for micromachined heater application. Thermal measurements (in dynamic and static modes) were performed on micro-heaters commonly used in microsystems, platinum- and silicon-based micromachined heaters. The results show the capability of the method in terms of the thermal resolution and spatial resolution as well as the capacity to quickly obtain static and dynamic thermal images of the studied sample