ELECTROMIGRATION RELIABILITY OF CU/LOW K INTERCONNECTS

The distinct EM behavior of Cu interconnects induced by the dual-damascene structure and process will be first discussed and compared with Al interconnects. The statistical approach used to study EM failure statistics and threshold current density-length products will be presented first for Cu/oxide structures, and then compared with Cu/low k structures. The impact of weak thermomechanical properties of low k dielectrics on EM reliability will be assessed based on the concept of effective elastic modulus. Finally the recent development using interfacial layer to improve Cu EM reliability will be discussed.

Dr. Paul S. Ho is the Director of the Laboratory for Interconnect and Packaging at the University of Texas at Austin. He received his B.S. degree from National Chengkung University, Taiwan, M.S. degree from the National Tsinghua University, Taiwan and Ph.D. degree from Rensselaer Polytechnic Institute. He joined the Materials Science and Engineering Department at Cornell University in 1966 and became an Associate Professor in 1972. In 1972, he joined the IBM T.J. Watson Research Center and has held a number of management positions. In 1985, he became Senior Manager of the Interface Science Department. In 1991, he joined the faculty at the University of Texas and was appointed the Cockrell Family Regents Chair in Materials Science and Engineering. His current research is in the area of materials, processing and reliability study for interconnect and packaging for microelectronics. He is a Fellow of IEEE, the American Physical Society and the American Vacuum Society.