Side-by-side comparison between infrared and thermoreflectance imaging using a thermal test chip with embedded diode temperature sensors

A side-by-side comparison between thermoreflectance imaging (TR) and infrared (IR) imaging is made using a specially designed thermal test chip with an embedded diode sensor array. IR thermal imaging is commonly used in industry. However, due to the infrared wavelength and the diffraction limit, IR has limited spatial resolution for chip level thermal characterization. In this paper we compare the spatial, thermal, and temporal resolutions of IR and TR methods and verify the results with integrated diode temperature sensors in the test chip. Thermoreflectance imaging showed higher spatial resolution, temporal resolution, and temperature accuracy on the metal heater. Infrared imaging showed to be less accurate on the metal without any coating to improve the emissivity. The TR measurement on the diode was within 1.7% of the diode reading, while the IR measurement was within 6%.