Patents by Inventor Alan E. Walter

Alan E. Walter 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: 6348101
    Abstract: An object is treated by contacting it with an organic solvent and then removing the organic solvent by directly displacing it with a fluid comprising a drying vapor (e.g., isopropyl alcohol or IPA vapor) such that substantially no liquid droplets of organic solvent are left on the surfaces of the object to evaporate after the direct displacement of the organic solvent with the fluid.
    Type: Grant
    Filed: September 26, 2000
    Date of Patent: February 19, 2002
    Assignee: CFMT, Inc.
    Inventor: Alan E. Walter
  • Patent number: 6143087
    Abstract: An object is treated by contacting it with an organic solvent and then removing the organic solvent by directly displacing it with a fluid comprising a drying vapor (e.g., isopropyl alcohol or IPA vapor) such that substantially no liquid droplets of organic solvent or drying vapor are left on the surfaces of the object to evaporate after the direct displacement of the organic solvent with the fluid.
    Type: Grant
    Filed: February 19, 1999
    Date of Patent: November 7, 2000
    Assignee: CFMT, Inc.
    Inventor: Alan E. Walter
  • Patent number: 4984597
    Abstract: Object surfaces such as semiconductor wafers which are suspended in a rinsing fluid may be dried by replacing the rinsing fluid, such as water, with a drying vapor by directly displacing the water from the surfaces at such a rate that substantially no liquid droplets are left on the surfaces after replacement of the water with drying vapor. Preferably, the drying vapor is miscible with water and forms a minimum-boiling azeotrope with water, such as isopropanol. The drying vapor is then purged with a stream of dry, inert, noncondensable gas such as nitrogen. A vaporizer with automatic refill mechanism produces saturated drying vapor which may then be flashed to a superheated vapor prior to contacting the surfaces, which preferably are at the same temperature as the vapor. Preferably, no liquid is removed by evaporation, and the drying takes place in an enclosed, hydraulically full system which does not require movement or handling of the surfaces between rinsing and drying steps.
    Type: Grant
    Filed: November 3, 1989
    Date of Patent: January 15, 1991
    Assignee: CFM Technologies Research Associates
    Inventors: Christopher F. McConnell, Alan E. Walter
  • Patent number: 4917123
    Abstract: Contamination of wafers is reduced by an enclosed full-flow method and apparatus for the cleaning and other wet processing of semiconductor wafers. Process fluids flow sequentially and continuously past the wafers such that the processing does not require movement or operator handling of the wafers between processing steps. The vessel containing the wafers is hydraulically full during each process step. Wafers may be cleaned using a hot corrosive fluid, such as sulfuric acid; rinsed using high purity water at high flow rates; and dried using a drying fluid such as isopropanol. In addition, chemical reagents such as dilute hydrofluoric acid or hydrogen peroxide may be precisely mixed in situ and applied to the wafer surface for a precisely controlled period, by injecting concentrated reagent into rinse water purified by multipass filtration.
    Type: Grant
    Filed: October 3, 1988
    Date of Patent: April 17, 1990
    Assignee: CFM Technologies Limited Partnership
    Inventors: Christopher F. McConnell, Alan E. Walter
  • Patent number: 4911761
    Abstract: Object surfaces such as semiconductor wafers which are suspended in a rinsing fluid may be dried by replacing the rinsing fluid, such as water, with a drying vapor by directly displacing the water from the surfaces at such a rate that substantially no liquid droplets are left on the surfaces after replacement of the water with drying vapor. Preferably, the drying vapor is miscible with water and forms a minimum-boiling azeotrope with water, such as isopropanol. The drying vapor is then purged with a stream of dry, inert, non-condensable gas such as nitrogen. A vaporizer with automatic refill mechanism produces saturated drying vapor which may then be flashed to a superheated vapor prior to contacting the surfaces, which preferably are at the same temperature as the vapor. Preferably, no liquid is removed by evaporation, and the drying takes place in an enclosed, hydraulically full system which does not require movement or handling of the surfaces between rinsing and drying steps.
    Type: Grant
    Filed: April 20, 1988
    Date of Patent: March 27, 1990
    Assignee: CFM Technologies Research Associates
    Inventors: Christopher F. McConnell, Alan E. Walter
  • Patent number: 4899767
    Abstract: A system for the fluid treatment of semiconductor wafers includes a treatment vessel having opposed first and second ports, and means for holding wafers in a flow path therebetween. A flow segment comprising in sequence, a first vent, a first valve, an inlet, a second valve and a second vent extends between the first and the second port so as to constitute, together with the vessel, a closed fluid loop.A fluid delivery system for the delivery of a sequence of high purity treatment fluids to a treatment vessel includes a measuring tank having opposed ports and configured for plug flow between the ports, and a metering pump having its inlet connected to a said port for withdrawing metered amounts of fluid from the tank. A plurality of reservoirs of treatment fluid are each connected via a respective associated valve to one of the said ports.
    Type: Grant
    Filed: December 12, 1988
    Date of Patent: February 13, 1990
    Assignee: CFM Technologies, Inc.
    Inventors: Christopher F. McConnell, Alan E. Walter
  • Patent number: 4795497
    Abstract: A method for the fluid treatment of semiconductor wafers includes a treatment vessel having opposed first and second ports, and means for holding wafers in a flow path therebetween. A flow segment comprising in sequence, a first vent, a first valve, an inlet, a second valve and a second vent extends between the first and the second port so as to constitute, together with the vessel, a closed fluid loop.Preferably, the first and second ports are top and bottom ports, with a flow path extending vertically therebetween. The loop is maintained hydraulically full, whereby filling the vessel with a treatment fluid at the inlet, flushes a preceding treatment fluid from the system. A sequence of treatment fluids of differing densities may be provided at the inlet, and a vent and a valve are controlled to fill the loop from the bottom, in the event the treatment fluid is denser than the preceding fluid, or from the top, in the event the fluid is lighter than the preceding fluid.
    Type: Grant
    Filed: December 4, 1985
    Date of Patent: January 3, 1989
    Inventors: Christopher F. McConnell, Alan E. Walter
  • Patent number: 4778532
    Abstract: Contamination of wafers is reduced by an enclosed full-flow method and apparatus for the cleaning and other wet processing of semiconductor wafers. Process fluids flow sequentially and continuously past the wafers such that the processing does not require movement or operator handling of the wafers between processing steps. The vessel containing the wafers is hydraulically full during each process step. Wafers may be cleaned using a hot corrosive fluid, such as sulfuric acid; rinsed using high purity water at high flow rates; and dried using a drying fluid such an isopropanol. In addition, chemical reagents such as dilute hydrofluoric acid or hydrogen peroxide may be precisely mixed in situ and applied to the wafer surface for a precisely controlled period, by injecting concentrated reagent into rinse water purified by multipass filtration.
    Type: Grant
    Filed: August 13, 1985
    Date of Patent: October 18, 1988
    Assignee: CFM Technologies Limited Partnership
    Inventors: Christopher F. McConnell, Alan E. Walter
  • Patent number: 4633893
    Abstract: An improved apparatus for enclosed flow-line semiconductor wafer treatment includes a wafer-containing vessel and a mechanism for imparting plug-flow to a treatment fluid flowing into the vessel. One plug-flow imparting mechanism includes a flow-expansion input element and a fixed helical flow-diverting surface. Another mechanism incorporates a rotating flow diverting surface.
    Type: Grant
    Filed: June 24, 1985
    Date of Patent: January 6, 1987
    Assignee: CFM Technologies Limited Partnership
    Inventors: Christopher F. McConnell, Alan E. Walter