Backside Infrared Imaging of Integrated Circuits Using Refraction-Assisted Illumination

Abstract This article demonstrates a simple and robust backside illumination method for infrared imaging of ICs. The technique uses oblique illumination, which removes surface noise components while providing bright-field illumination under the surface, and requires only modest if any polishing of the backside of the substrate. As the examples in the article show, it can be implemented with a standard microscope with IR optics, yielding high contrast, high resolution images without the need for complex lenses, AR coatings, or sophisticated scanning electronics.