Electrical Engineering
      and Computer Sciences

Electrical Engineering and Computer Sciences


UC Berkeley


2009 Research Summary

An Air-Corridor Interconnect Structure

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Jemin Park and Chenming Hu

Samsung and ERSO Chair fund

We propose a novel mostly-air interconnect structure. Every metal line is surrounded by an air arch on the sides and overhead. It is supported on the bottom by a series of solid dielectric beams. The vias are also surrounded by air sheaths. The arch of an air gap not only has lower effective capacitance but also higher stability of structure. Raphael simulation shows that the total capacitance is reduced by about 45% and the RC delay is decreased about 55%. The effective dielectric constant can be reduced to about 1.7 using existing dielectric with k = 2.9.

Figure 1
Figure 1: 3D structures of our BEOL process with air gap: (a) tilt view of the structure; (b) front view of the structure; and (c) side view of the structure

B. Shieh, K. C. Saraswat, J. P. McVittie, S. List, S. Nag, M. Islamraja, and R. H. Havemann, "Air-Gap Formation During IMD Deposition to Lower Interconnect Capacitance," Electron Device Letters, Vol. 19, No. 1, January 1998.
M. B. Anand, M. Yamada, and H. Shibata, "Use of Gas as Low-k Interlayer Dielectric in LSI's: Demonstration of Feasibility," Electron Device, Vol. 44, No. 11, November 1997.
C.-Hui Chen, Y.-K. Fang, C.-S. Lin, C.-W. Yang, and T.-C. Hsieh, "A Novel Multi-level Interconnect Scheme with Air as Low K Inter-Metal Dielectric for Ultradeep Submicron Application," Solid-State Electrons, Vol. 45, 2001, pp. 199-203.
RAPHAEL User Manual, Synopsys, Mountain View, CA.