Copper metallization for high performance silicon technology

The increasingly rapid transition of the electronics industry to high-densi ty, high-performance multifunctional microprocessor Si technology has preci pitated migration to new materials alternatives that can satisfy stringent requirements. One of the recent innovations has been the substitution of co pper for the standard aluminum-copper metal wiring in order to decrease res istance and tailor RC delay losses in the various hierarchies of the wiring network. This has been accomplished and the product shipped only since the fall of 1998, after more than a decade of intensive development. Critical fabrication innovations include the development of an electroplating proces s for the copper network, dual-damascence chem-mech polishing (CMP), and ef fective liner material for copper diffusion barrier and adhesion promotion. The present copper technology provides improved current-carrying capabilit y by higher resistance to electromigration, no device contamination by copp er migration, and the performance enhancement analytically predicted. This success of the shift to copper will accelerate the industry movement to fin er features and more complex interconnect structures with sufficient device density and connectivity to integrate full systems on chips. The next inno vation will be the introduction of low-dielectric constant material that, i n combination with copper, will create added excitement as the industry lea rns how to utilize this new capability.