Failure analysis engineers apply a combination of conventional static fault isolation tools such as OBIRCH, PEM, or lock-in thermography (LIT) to detect simple short defects. However, if the defect is located in a complex circuit, analysis can be more challenging. Laser voltage probing and imaging (LVx) is widely used but will have difficulty in localizing a defect in the backend layers. The combination of LVx and LIT can resolve complex short cases that either of these techniques alone cannot easily do. This paper introduces the thermal effect of LVx and applications of LIT for functional analysis, and it describes and provides case histories for complementary fault isolation procedures for detecting defects in metal layers and transistors.