Temperature measurements on metallic lines under current stresses by laser probing and correlation with electromigration tests at wafer level

Wafer-level monitoring of electromigration is widely investigated. For this purpose, test structures with specific geometrical features have been proposed allowing very accelerated tests; they are called `SWEAT' structures. The aim of this contribution is to present a method for the study of the thermal behavior of such devices. Laser probing offers a contactless investigation method with excellent lateral resolution, compared with the classical IR thermography. This method allows us to determine the temperature profile along the SWEAT structure axis. Electromigration data (i.e., failure location) are presented and interpreted based on the knowledge of the temperature along the structure.