Patents by Inventor Sudarshan Lal

Sudarshan Lal 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: 5955150
    Abstract: Proposed is a technique for determining the suitability of use of a material for an electroless plating operation. A solution including the material is subject to an anodic linear sweep voltammetric measurement. The resulting anodic peak is compared with that of a control solution in order to evaluate the potential of the material for poisoning a factory plating bath.
    Type: Grant
    Filed: March 25, 1997
    Date of Patent: September 21, 1999
    Assignee: Lucent Technologies Inc.
    Inventor: Sudarshan Lal
  • Patent number: 5523001
    Abstract: A method for treating the waste stream resulting from electroless plating operations such as copper electroless plating. The waste stream is simultaneously treated with hydrogen peroxide and UV light to bring the level of contaminants below the discharge limit. In one embodiment, the waste stream is also diluted with rinse water from the plating process.
    Type: Grant
    Filed: December 30, 1994
    Date of Patent: June 4, 1996
    Assignee: AT&T Corp.
    Inventors: Eugene P. Foeckler, Jr., Sudarshan Lal
  • Patent number: 5501777
    Abstract: Disclosed is a method for testing solder mask material for suitability with an electroless plating process. The Emix potential of the electroless bath is measured. A test substrate including the mask material is then immersed in an electrolyte, and a constant potential at least equal to the Emix potential is applied to a pair of electrodes also immersed in the electrolyte. The test substrate is then inspected to determine adherence of the mask material.
    Type: Grant
    Filed: December 30, 1994
    Date of Patent: March 26, 1996
    Assignee: AT&T Corp.
    Inventors: Donald Dinella, Sudarshan Lal, Kim L. Morton, David A. Nicol
  • Patent number: 5472585
    Abstract: Disclosed is a method for removal of contaminants and replenishment of an electroless copper plating solution in order to allow reuse of the solution. Copper oxide is dissolved in the spent solution and this is followed by an electrodialysis which removes formate and carbonate ions.
    Type: Grant
    Filed: November 30, 1994
    Date of Patent: December 5, 1995
    Assignee: AT&T Corp.
    Inventors: Donald Dinella, Sudarshan Lal, David A. Nicol
  • Patent number: 5384153
    Abstract: Disclosed is a method of monitoring electroless plating solutions. The solutions are used to plate a light-transmitting medium. Measurements are made to determine the time it takes for light transmission through the medium to be reduced to a certain level. This measurement can be used to determine whether articles will be sufficiently plated by the solutions.
    Type: Grant
    Filed: March 10, 1993
    Date of Patent: January 24, 1995
    Assignee: AT&T Corp.
    Inventors: Alfred J. Grady, Jr., Sudarshan Lal, Mary J. Mitchell, Yutaka Okinaka, Craig G. Smith, Harvey S. Trop, Chwan-Tsann Wang
  • Patent number: 5127991
    Abstract: This invention is a process for etching copper sheets on insulating boards for use in fabricating multilayer printed circuit boards. The improvement resides in adding to a standard copper etching solution certain alkyltrimethyl ammonium chlorides with alkyl chain lengths ranging from 6 to 20 carbon atoms in amounts sufficient to yield intermediate kinetics behavior. Of special interest are dodecyltrimethyl ammonium chloride, hexadecyltrimethyl ammonium chloride and octadecyltrimethyl ammonium chloride present in an amount of from 0.01 to 1.0 wt %. A silicon-based antiforming agent may be added in amounts of from 0.05 to 2.0 wt. % to prevent an unacceptably large amount of foam from occurring during etching. With this formulation, the rate is mass transport controlled at low rates and almost independent of mass transport at high rates due to the inhibition of the surface reaction rate.
    Type: Grant
    Filed: June 3, 1991
    Date of Patent: July 7, 1992
    Assignee: AT&T Bell Laboratories
    Inventors: Sudarshan Lal, Craig G. Smith
  • Patent number: 4330376
    Abstract: A process is provided for inhibiting the rate of corrosion of titanium metal surfaces from attack by strong acid media in which at least a portion of the titanium metal surface is coated with rhodium metal to provide a treated metal surface which is substantially impervious to corrosion by strong acid media. The article so prepared appears to be uniquely impervious to corrosion by strong acid media and is also claimed herein.
    Type: Grant
    Filed: July 17, 1980
    Date of Patent: May 18, 1982
    Assignee: Atlantic Richfield Company
    Inventors: Sudarshan Lal, Richard V. Porcelli
  • Patent number: 4238551
    Abstract: A process is provided for inhibiting the rate of corrosion of titanium metal surfaces from attack by strong acid media in which at least a portion of the titanium metal surface is coated with rhodium metal to provide a treated metal surface which is substantially impervious to corrosion by strong acid media. The article so prepared appears to be uniquely impervious to corrosion by strong acid media and is also claimed herein.
    Type: Grant
    Filed: March 5, 1979
    Date of Patent: December 9, 1980
    Assignee: Halcon Research & Development Corporation
    Inventors: Sudarshan Lal, Richard V. Porcelli