Patents Examined by Victor A. Mandalla, Jr.
  • Patent number: 6919639
    Abstract: Electromigration can be reduced in a copper-based metallization of an integrated circuit that includes a first copper-containing via that electrically connects an underlying conductive line and an overlying copper-containing line through an intervening insulating layer. Electromigration can be reduced by forming at least a second copper-containing via that electrically connects the underlying conductive line and the overlying copper-containing line through the intervening insulating layer, in parallel with the first copper-containing via. Multi-vias can provide redundancy to reduce early failure statistics. Moreover, since current is distributed among the vias, the electromigration driving force can be reduced and local Joule heating, in voids at the via interface, also may be reduced. Accordingly, even if via voids are formed, the structure may not fail by catastrophic thermal runaway due to Joule heating.
    Type: Grant
    Filed: October 15, 2002
    Date of Patent: July 19, 2005
    Assignee: The Board of Regents, the University of Texas System
    Inventors: Paul S. Ho, Ki-Don Lee, Ennis Ogawa, Hideki Matsuhashi