Investigation of self-heating phenomenon in small geometry vias using scanning Joule expansion microscopy

This paper reports the use of a novel thermometry technique, scanning Joule expansion microscopy (SJEM), to study the steady state and dynamic thermal behaviour of small geometry W-plug vias under sinusoidal and pulsed current stress for the first time. The spatial distribution of the temperature rise surrounding a sub-micron via has been determined and the corresponding temperature contour image has been extracted. The thermal time constant of the via structure has been determined from the measured AC frequency dependence of the temperature rise. Furthermore, the average (DC) and peak temperature rise under pulsed stress condition has been estimated from the measured first harmonic temperature rise.