Patents by Inventor Fred Mitchel

Fred Mitchel has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 6261158
    Abstract: A multi-step CMP system is used to polish a wafer to form metal interconnects in a dielectric layer upon which barrier and metal layers have been formed. A first polish removes an upper portion of the metal layer using a first slurry and a first set of polishing parameters, leaving residual metal within the dielectric layer to serve as the metal interconnects. A second polish of the wafer on the same platen and polishing pad removes portions of the barrier layer using a second slurry under a second set of polishing parameters. The second polish clears the barrier layer from the upper surface of the dielectric layer, thereby forming the metal interconnect. To reduce dishing and dielectric erosion, the second slurry is selected so that the barrier layer is removed at a faster rate than the residual metal within the dielectric layer. A cleaning step may be optionally performed between the first and second polishes.
    Type: Grant
    Filed: December 16, 1998
    Date of Patent: July 17, 2001
    Assignee: SpeedFam-IPEC
    Inventors: Karey Holland, Ajoy Zutshi, Fen Dai, Yehiel Gotkis, C. Jerry Yang, Dennis Schey, Fred Mitchel, Lin Yang