Patents Assigned to Purusar Corporation
  • Patent number: 4867799
    Abstract: A method is set forth of treating a surface of an object to remove impurities. The object is positioned within a treating chamber with the surface exposed. Ammonia vapor is contacted with water vapor and/or hydrogen peroxide vapor adjacent to the surface to provide a hot mixture comprising at least ammonia and ammonium hydroxide. The hot mixture is impinged on the surface. The contacting is immediately prior to and/or simultaneous with the impinging. Resist is quickly stripped from the surfaces of semiconductors by this method. And, the stripping is very complete. Group I and Group II metals are also removed.
    Type: Grant
    Filed: September 10, 1987
    Date of Patent: September 19, 1989
    Assignee: Purusar Corporation
    Inventor: Thomas J. Grebinski
  • Patent number: 4778536
    Abstract: A method is set forth of treating the surface of an object such as a semiconductor wafer to remove impurities. In particular, the method serves to strip resist in a short period of time, of the order of 30 seconds. The object is positioned with the surface exposed within a treating chamber. Water vapor is contacted with sulfur trioxide vapor adjacent the surface to provide a hot mixture comprising sulfur trioxide, water and sulfuric acid. The hot mixture is impinged onto the surface. The contacting is immediately prior to and/or simultaneous with the impinging. Photoresist is quickly and efficiently removed in accordance with this process. Energy requirements are relatively low since the components are easily vaporized.
    Type: Grant
    Filed: September 10, 1987
    Date of Patent: October 18, 1988
    Assignee: Purusar Corporation
    Inventor: Thomas J. Grebinski
  • Patent number: 4695327
    Abstract: A surface of an object, e.g., a semiconductor wafer, is treated to remove impurities, including those in microrecesses having minimum dimensions of ten microns or less. The object is positioned in a sealed chamber which has a limited number of potential spaceborne nucleation centers and is at a treating temperature, T. A condensable solvent is introduced into the chamber until its pressure is close to but below its vapor pressure at the temperature, T. This condition is maintained until a plurality of molecular layers of the solvent is adsorbed in the microrecesses. Then, the pressure of the solvent is increased to at least unity whereat it condenses in the microrecesses. Impurities can be removed from the microrecesses in this manner thus improving product quality.
    Type: Grant
    Filed: June 13, 1985
    Date of Patent: September 22, 1987
    Assignee: Purusar Corporation
    Inventor: Thomas J. Grebinski