Simultaneous Measurement of Temperature and Strain in Electronic Packages Using Multiframe Super-Resolution Infrared Thermography and Digital Image Correlation

Abstract

For microelectronic components and systems, reliability under thermomechanical stress is of critical importance and relies on accurate mapping of surface hotspots and temperature gradients. One method of non-invasively acquiring this data is through infrared (IR) thermography. However, IR thermography is often limited by the typically low resolution of such cameras. Additionally, the surface finish preparations required to infer physical deformation using digital image correlation (DIC) interferes with the ability to measure the temperature with IR thermography, which prefers a uniform high emissivity. This work introduces a one-shot technique for the simultaneous measurement of surface temperature and deformation using multiframe super-resolution-enhanced IR imaging combined with digital image correlation (DIC) analysis. Multiframe super-resolution processing uses several sub-pixel shifted images to extract a single higher-resolution image. Measurement of physical deformation is incorporated using a test sample with a black background and low-emissivity speckle features. Through processing and filtering, data from the black surface regions used for surface temperature mapping are separated from the speckle features used to track deformation with DIC. This method allows DIC to be performed on the IR images, yielding a deformation field consistent with applied tensioning. While both the low- and super-resolution data sets can be successfully processed with DIC, super-resolution helps reduce noise in the extracted deformation fields. As for temperature measurement, using super-resolution is shown to allow for better removal of the speckle features, as quantified by a lower mean deviation from the spatial moving average.