ELECTROMIGRATION RESISTANCE OF TIWN CU/TIWN INTERCONNECTIONS/

The present paper describes the activation energy for electromigration damage (EMD) of the Cu multilayer interconnection. The Cu multilayer (TiWN/Cu/TiWN) interconnections (width similar to 0.7 mu m) were fabri cated by the Ar-sputtering method. The electromigration (EM) resistanc e measurements were carried out on a wafer level. The AlCu multilayer (TiN/AlCu/TiN/Ti) interconnections were also prepared by the conventio nal process, and EM resistance was evaluated by the same method. A cur rent density applied to the interconnection was in the range of 16 to 24 MA/cm(2). After the EM test, voids were formed in the Cu layer of t he TiWN/Cu/TiWN multilayer, and the Cu hillocks were formed at the ano de side. The activation energies for electromigration damage (EMD) of the Cu and AlCu interconnections were 0.97 and 0.62 eV, respectively, The activation energies and medium time to failures (MTF) of Cu and Al Cu showed that the lifetime of the Cu interconnections at 110 degrees C was about three orders of magnitude longer than that of AlCu.