The future of interconnection technology

Continuing advances in interconnection technology are seen as essential to continued improvements in integrated circuit performance. The recent introduction of copper metallization, dual-damascene processing, and fully articulated hierarchical wiring structures, along with the imminent introduction of low-dielectric-constant insulating materials, indicates an accelerating pace of innovation. Nevertheless, some authors have argued that such innovations will sustain chip-level performance improvements for only another generation or two. In light of this pessimism, current trends and probable paths in the future evolution of interconnection technology are reviewed. A simple model is developed and used to estimate future wiring requirements and to examine the value of further innovations in materials and architecture. As long as current trends continue, with memory arrays filling an increasing fraction of the total area of high-performance microprocessor chips, wiring need not be a performance limiter for at least another decade. Alternative approaches, such as optical interconnections on chip, have little to offer while the incremental elaboration of the traditional wiring systems is still rapidly advancing.