Methods and apparatus for non-contact thermal measurement which are
capable of providing sub micron surface thermal characterization of
samples, such as active semiconductor devices. The method obtains thermal
image information by reflecting a light from a surface of a device in
synchronous with the modulation of the thermal excitation and then
acquiring and processing an AC-coupled thermoreflective image. The method
may be utilized for making measurements using different positioning
techniques, such as point measurements, surface scanning, two-dimensional
imaging, and combinations thereof. A superresolution method is also
described for increasing the resultant image resolution, based on
multiple images with fractional pixel offsets, without the need to
increase the resolution of the image detectors being utilized. The
thermoreflective method provides a spatial resolution better than current
infrared cameras, operates within a wide temperature range, and is
capable of a thermal resolution on the order of 10 mK.degree..