Patents by Inventor Ravindran Periasamy

Ravindran Periasamy 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: 5472550
    Abstract: An apparatus for processing a substrate surface in a process chamber wherein during chemical or physical altering of the substrate surface a laser beam is projected inside the processing chamber and along a trajectory which does not contact the substrate surface in order to capture particles by means of the photophoretic effect, particles which would otherwise impinge upon and contaminate the substrate surface.
    Type: Grant
    Filed: June 13, 1994
    Date of Patent: December 5, 1995
    Assignee: Research Triangle Institute
    Inventor: Ravindran Periasamy
  • Patent number: 5439513
    Abstract: A device for controlling the motion of particles suspended in a gas stream is provided, including a pipe, through which at least a fraction of the gas stream flows, a source of AC voltage, a source of DC voltage, and a plurality of electrode sets positioned within the pipe in series, generating an inhomogeneous electric field to cause the particles suspended in the gas stream to concentrate into a narrow axial region in the center of the pipe. Each electrode set includes a first pair of opposed hyperboloidally shaped electrodes connected to the AC voltage source and a second pair of opposed hyperboloidally shaped electrodes connected to the DC voltage. The first and second pairs of opposed electrodes are positioned at spaced apart intervals around the circumference of the pipe to define an opening through which at least a fraction of the gas stream flows. The electrode sets are positioned within the pipe in series such that the gas stream flows through the openings defined by each successive electrode set.
    Type: Grant
    Filed: May 31, 1994
    Date of Patent: August 8, 1995
    Assignee: Research Triangle Institute
    Inventors: Ravindran Periasamy, David S. Ensor, Robert P. Donovan
  • Patent number: 5366559
    Abstract: A method for processing a substrate surface in a process chamber wherein during chemical or physical altering of the substrate surface a laser beam is projected inside the processing chamber and along a trajectory which does not contact the substrate surface in order to capture particles by means of the photophoretic effect, particles which would otherwise impinge upon and contaminate the substrate surface.
    Type: Grant
    Filed: May 27, 1993
    Date of Patent: November 22, 1994
    Assignee: Research Triangle Institute
    Inventor: Ravindran Periasamy
  • Patent number: 5229171
    Abstract: An apparatus and method including a droplet coating generator for generating a stream of electrically charged coating droplets within an evacuable chamber towards a substrate positioned within the evacuable chamber. A piezoelectric vibrator and orifice plate coupled thereto generate the stream of coating droplets. The coating droplets are urged to move in a sweeping motion across the substrate by at least one pair of opposing spaced apart electrodes powered by an electrical power supply. A uniform coating is thus produced while the evacuable chamber is maintained at subatmospheric pressure as required during typical semiconductor processing. Multiple applications of a photoresist coating may be applied by the coating apparatus without requiring that the evacuable chamber be repeatedly vented and pumped down to subatmospheric pressure.
    Type: Grant
    Filed: December 23, 1991
    Date of Patent: July 20, 1993
    Assignee: Research Triangle Institute
    Inventors: Robert P. Donovan, Ravindran Periasamy, Anthony C. Clayton, David S. Ensor