Patents by Inventor William L. Hofer

William L. Hofer 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).

  • Publication number: 20020142593
    Abstract: A plasma etching machine comprises a process chamber defining an interior region and including a bottom wall having an aperture and a block disposed in the aperture and including a longitudinally extending bore. A shaft extends through the bore and includes a spider push rod extending longitudinally therethrough. An internally cooled chuck is coupled to the shaft and disposed in the interior region and cooperates with the shaft to define a chamber. A spider is disposed in the chamber and is coupled to the push rod. A lift mechanism is coupled to the shaft and the push rod so that the spider pushes up on a wafer in response to actuation of the lift mechanism. A wafer clamping mechanism is coupled to the push rod if a mechanical clamp is used. In the case of electrostatic clamp the bias applied to the chuck is coupled with the use of a rotational roller to allow the bias to be applied to the chuck for the duration of the etch process. A RF source is needed for ionization of the gas.
    Type: Application
    Filed: February 22, 2000
    Publication date: October 3, 2002
    Inventors: Rodney C. Langley, David R. Johnson, William L. Hofer