Patents by Inventor Christopher W. Burkhart

Christopher W. Burkhart 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: 5425803
    Abstract: An apparatus and a method for delivering a liquid are disclosed. The liquid contained in a vessel is subjected to a pressurized gas. Any pressurized gas dissolved in the liquid is removed in a degas module by passing the liquid through a gas permeable tube subjected to a pressure differential. Then the liquid is dispensed by a liquid mass flow controller.
    Type: Grant
    Filed: July 5, 1994
    Date of Patent: June 20, 1995
    Assignee: Novellus Systems, Inc.
    Inventors: Bart J. van Schravendijk, Christopher W. Burkhart, Tito H. Santiago, Charles E. Pomeroy, Jeffrey W. Lind
  • Patent number: 5374594
    Abstract: A suitable inert gas such as argon or a mixture of inert and reactive gases such as argon and hydrogen is introduced onto the backside of wafers being processed in a CVD reactor during the deposition of tungsten or other metals, metal nitrides and silicides, to avoid deposition of material on the backside of the wafers being processed. Each process station includes a gas dispersion head disposed over a platen. A vacuum chuck including a number of radial and circular vacuum grooves in the top surface of the platen is provided for holding the wafer in place. A platen heater is provided under the platen. Backside gas is heated in and about the bottom of the platen, and introduced through a circular groove in the peripheral region outside of the outermost vacuum groove of the vacuum chuck. Backside gas pressure is maintained in this peripheral region at a level greater than the CVD chamber pressure.
    Type: Grant
    Filed: January 22, 1993
    Date of Patent: December 20, 1994
    Assignee: Novellus Systems, Inc.
    Inventors: Everhardus P. van de Ven, Eliot K. Broadbent, Jeffrey C. Benzing, Barry L. Chin, Christopher W. Burkhart
  • Patent number: 5238499
    Abstract: A suitable inert gas such as argon or a mixture of inert and reactive gases such as argon and hydrogen is introduced onto the backside of wafers being processed in a CVD reactor during the deposition of tungsten or other metals, metal nitrides and silicides, to avoid deposition of material on the backside of the wafers being processed. Each process station includes a gas dispersion head disposed over a platen. A vacuum chuck including a number of radial and circular vacuum grooves in the top surface of the platen is provided for holding the wafer in place. A platen heater is provided under the platen. Backside gas is heated in and about the bottom of the platen, and introduced through a circular groove in the peripheral region outside of the outermost vacuum groove of the vacuum chuck. Backside gas pressure is maintained in this peripheral region at a level greater than the CVD chamber pressure.
    Type: Grant
    Filed: March 25, 1991
    Date of Patent: August 24, 1993
    Assignee: Novellus Systems, Inc.
    Inventors: Everhardus P. van de Ven, Eliot K. Broadbent, Jeffrey C. Benzing, Barry L. Chin, Christopher W. Burkhart
  • Patent number: 5230741
    Abstract: A suitable inert gas such as argon or a mixture of inert and reactive gases such as argon and hydrogen is introduced onto the backside of wafers being processed in a CVD reactor during the deposition of tungsten or other metals, metal nitrides and silicides, to avoid deposition of material on the backside of the wafers being processed. Each process station includes a gas dispersion head disposed over a platen. A vacuum chuck including a number of radial and circular vacuum grooves in the top surface of the platen is provided for holding the wafer in place. A platen heater is provided under the platen. Backside gas is heated in and about the bottom of the platen, and introduced through a circular groove in the peripheral region outside of the outermost vacuum groove of the vacuum chuck. Backside gas pressure is maintained in this peripheral region at a level greater than the CVD chamber pressure.
    Type: Grant
    Filed: July 16, 1990
    Date of Patent: July 27, 1993
    Assignee: Novellus Systems, Inc.
    Inventors: Everhardus P. van de Ven, Eliot K. Broadbent, Jeffrey C. Benzing, Barry L. Chin, Christopher W. Burkhart
  • Patent number: 4575069
    Abstract: A sheet handling path extending from an entrance location to an exit location is provided by a small diameter rotatable roller and several parallel transversely spaced flexible belts. At the exit location, several deflector arms mounted on an actuator shaft initially deflect the leading portion of an exiting sheet towards the forward wall of an underlying receiving tray. An exit roller may also be provided at the exit location. After the leading edge of a sheet has reached the forward wall and the sheet has started to form a buckle, the deflector arms are rotated to a remote position permitting the sheet to be translated rearwardly by friction between the overlying flexible belts and the sheet until a trailing edge of the sheet springs clear of the belts and settles under its own weight into the receiving tray.
    Type: Grant
    Filed: May 13, 1983
    Date of Patent: March 11, 1986
    Assignee: Qume Corporation
    Inventor: Christopher W. Burkhart
  • Patent number: 4459844
    Abstract: A portable leak detector is disclosed for use with, say, helium as a tracer gas. The leak detector includes an improved separation chamber, an air pump for pumping the sample gas, a high vacuum spectrometer, and a small and lightweight evacuation pump. The separation chamber is formed by an air-tight enclosure which has an inlet duct, an outlet duct, and a tubular separation membrane extending between manifolds connected to the ducts. Gas samples are collected by a gas sampling probe and pumped by an air pump into the inlet duct of the separation chamber, through multiple parallel tubes of the tubular membrane material, and out the outlet duct of the separation chamber where it is exhausted. The multiple tubes are formed of a selectively-permeable membrane material such as Tefzel which permits the rapid diffusion of helium therethrough but which has relatively low permeability for other gases contained in the gas sample.
    Type: Grant
    Filed: June 17, 1982
    Date of Patent: July 17, 1984
    Assignee: Smith & Denison
    Inventor: Christopher W. Burkhart