Office of Technology Transfer – University of Michigan

Active Shielding of On-chip Global Intercoreaction

Technology #2354

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Dennis Sylvester
Managed By
Joohee Kim
Licensing Specialist, Physical Sciences & Engineering 734-764-8202


Wires that propagate signals between logic stages on an integrated circuit can be implemented in different widths. The chosen width for such wires in a given integrated chip has significant affects on the propagation characteristics of the signal being carried over the wires. Certain integrated circuit applications, such as clock nets, require very fast signal transition times on the wires. To achieve the required signal transition times, such applications commonly use relatively wide wires to propagate signals between logic stages. However, the use of relatively wide wires results in ringing on the wire caused by the increased inductive characteristics. To reduce the undesirable affects associated with relatively wide wires, it is typical to incorporate “shields” for the wires on the integrated circuits. While passive shielding of signaling wires on an integrated chip improves the signal propagation characteristics of the signaling wires, it does not improve the characteristics enough for certain very wide wires, such as clock nets on integrated circuits.


Researchers at the University of Michigan have developed a system for propagating an electrical voltage signal method that reduces the adverse affects associated with inductive signaling wires on integrated circuits while maintaining or improving desirable signal propagation characteristics. The system includes an elongated electrical conducting signal wire over which the electrical voltage signal is propagated, and a pair of electrical conducting shielding wires positioned parallel to and on opposite longitudinal sides of said signal wire, and a shielding signal applied to the pair of shielding wires. The shielding signal is configured to be out of phase with the electrical voltage signal. Unlike conventional (passive) shielding, this active approach speeds up signal propagation on a wire by ensuring in-phase switching of adjacent nets. Specifically, it enables lower delays and faster signal slopes without the expense of higher power consumption and slightly degraded noise properties. This technology alleviates problems associated with decreasing wire dimensions and increasing die size.

Applications and Advantages


  • Propagation of an electrical voltage signal-nl-on an integrated circuit chip
  • For densely packed wires


  • Active shielding reduces the ringing affect-nl-on the signaling wire
  • Increased integrity, reliability, and propagation-nl-speed of the signal