The effects of rapid thermal annealing treatment upon the microstructural parameters of the electromigration resistance of electroplated Cu films were determined by using scanning electron microscopy, atomic force microscopy and X-ray diffraction analysis. Electron backscattered diffraction patterns were used to characterize the texture of the Cu thin films. It was found that the electromigration resistance of the electroplated Cu film increased upon increasing the annealing temperature from 200 to 500C. It was noted that N was more favorable than vacuum as a rapid thermal annealing atmosphere, since a N atmosphere offered a lower resistivity and smoother film surface. Also the dependence of the bamboo structure upon the annealing temperature and the line-width of the Cu interconnect was considered. If the line-width was 0.25μ, a bamboo structure was obtained by rapid thermal annealing at above 500C. On the other hand, if it was less than 0.1μm, rapid thermal annealing at any temperature above 200C resulted in a bamboo structure.

Electromigration Resistance-Related Microstructural Change with Rapid Thermal Annealing of Electroplated Copper Films. D.Kwon, H.Park, C.Lee: Thin Solid Films, 2005, 475[1-2], 58-62