THE EVOLUTION OF INTERCONNECTION TECHNOLOGY AT IBM

Advances in interconnection technology have played a key role in allowing continued improvements in integrated circuit density, performance, and cost. IBM contributions to interconnection technology over approximately the last ten generations of semiconductor products are reviewed. The development of a planar, back-end-of-line (BEOL) technology, used in IBM DRAM, bipolar, and CMOS logic products since 1988, has led to a threefold increase in the number of wiring levels, aggressive wiring pitches at all interconnection levels, and high-leverage design options such as stacked contacts and vias. Possible future BEOL technologies are also discussed, with emphasis on the use of higher-conductivity wiring and lower-dielectric-constant insulators. It is expected that their use will result in higher performance and reliability. Applications include future, lower-power devices as well as more cost-effective, higher-performance versions of present-day designs.