Patents Represented by Attorney, Agent or Law Firm Mark A. Littman & Assoc. P.A.
  • Patent number: 6468439
    Abstract: A process for the etching of multiple layers of at least two different metals comprisies: forming a resist pattern over a first layer of metal, said resist pattern having a pattern of openings therein, applying a first etch solution onto said resist pattern so that at least some etch solution contacts exposed areas of the first layer of metal, etching away the majority of the depth of the first metal in exposed areas of metal in the first layer of metal, applying a second etch solution onto the resist pattern the second etch solution having a rate of etch towards the first metal as compared to the first etch solution that is at least 20% less than the millimeter/minute rate of etch of the first etch solution at the same etch solution temperature, removing the second etch solution from said resist pattern after at least the first metal layer has been etched sufficiently to expose areas of a second metal layer underlying the first metal layer by forming an etched first metal layer, and applying a third etch so
    Type: Grant
    Filed: November 1, 1999
    Date of Patent: October 22, 2002
    Assignee: BMC Industries, Inc.
    Inventors: Donald A. Whitehurst, Paul D. Wyatt, Charles Ring, Michael J. Dufresne, Jose F. Brenes, Bruce A. Finger, Dave R. Zeipelt