Copper interconnect: migration or bust

"Moore's Law" is losing momentum due to the skyrocketing cost of capital equipment, shortened product life, diminishing returns and tougher technical challenges. Fundamental changes in technology, manufacturing and asset management are required to keep the momentum going. The introduction of copper interconnects is an example of a technology change in wiring required for the next few generation technology nodes. New interconnect schemes and materials are needed to drive the performance and improve the reliability of next generation ICs. Due to its low resistivity, high electromigration resistance and likely "lower" processing cost, copper has been identified as the best candidate to replace aluminum. Better performance is obtained when Cu is combined with "low-k" dielectrics and optimized design. Low-resistivity copper allows use of fewer interconnect layers for logic circuitry. Consequently, compared to the existing metallization scheme, Cu wiring offers the best combination in performance/reliability and cost of ownership requirements. However, there are also potential drawbacks and serious processing challenges to be addressed.