Forensic characterization of thin film resistor degradation

Experienced reliability engineers and failure analysts often rely on visual aspects of degradation and destruction to reconstruct events leading up to failure of semiconductor circuit elements. Often, the resulting theories about failure causes are tested by duplication experiments. These re-creations are typically evaluated and compared using those same visual attributes. This study is intended to establish the historical basis for visual comparison of nichrome resistor failures (a Rogues gallery of broken resistors) and then debunk correlation theories with simulations and empirical failure duplication results. The results will show that various visual failure characteristics can be reproduced by an unexpectedly wide range of applied stimulus. The final appearance of a “dead” resistor does not always portray how the part was “killed”.