Applied Physics

Crowding of Electrons Breaks the Links

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Science  11 May 2001:
Vol. 292, Issue 5519, pp. 1025
DOI: 10.1126/science.292.5519.1025a

Although the voltages applied to thin metal wires that connect integrated circuits in chips are small, the voltage drops across short distances can lead to high electric fields. These applied fields can cause electromigration of metal atoms, which can ultimately thin and break the wire. This problem is likely to be exacerbated as circuit dimensions continue to shrink. Localized crowding of current around the defective regions in the wire has been thought to accelerate deterioration, but this cause has so far lacked strong experimental evidence. Yongsunthon et al. used a magnetic field microscope to probe the current density along a 10-μm-wide gold wire decorated with small notches along its length. About 70% of the current was concentrated within a very short region (about 1 μm) in the vicinity of the notch edges. Although it is not clear from this work whether electromigration can be prevented, the results may provide clues for controlling its extent. — ISO

Appl. Phys. Lett.78, 2661 (2001).

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