Abstract
Soft defects—failures that manifest only under specific voltage, temperature, or frequency conditions—require specialized fault isolation techniques for accurate characterization. This paper demonstrates thermal response failure localization using scanning electron microscope (SEM) nanoprobing with an integrated thermal stage. While nanoprobing typically serves as the final step in fault isolation failure analysis (FIFA), thermal nanoprobing is essential for characterizing temperature-dependent parametric defects by enabling measurements at both passing and failing temperatures. We present three case studies: a "worse at cold" failure reproduction, a parametric root cause identification through thermal characterization, and a complex thermal failure that was uniquely isolatable through thermal nanoprobing. These cases illustrate the technique's effectiveness in analyzing temperature-dependent defects that occur outside room temperature conditions.