Patents Examined by Reenna Aurora
  • Method and apparatus for monitoring a metal layer during chemical mechanical polishing
    Patent number: 6924641
    Abstract: A sensor for monitoring a conductive film in a substrate during chemical mechanical polishing generates an alternating magnetic field that impinges a substrate and induces eddy currents. The sensor can have a core, a first coil wound around a first portion of the core and a second coil wound around a second portion of the core. The sensor can be positioned on a side of the polishing surface opposite the substrate. The sensor can detect a phase difference between a drive signal and a measured signal.
    Type: Grant
    Filed: May 19, 2000
    Date of Patent: August 2, 2005
    Assignee: Applied Materials, Inc.
    Inventors: Hiroji Hanawa, Nils Johansson, Boguslaw Swedek, Manoocher Birang