Patents by Inventor Anantha R. Sethuraman

Anantha R. Sethuraman 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: 6361415
    Abstract: The present invention advantageously provides a method and apparatus for polishing a semiconductor topography by applying a liquid which is void of particles between the topography and an abrasive polishing pad surface. The semiconductor topography is rotated relative to the polishing surface to polish elevationally raised regions of the topography. The particles are fixed within the polishing surface which may comprise a polymeric material. In one embodiment, the liquid may comprise water diluted with acid. If the liquid is adjusted to have a pH between 6.0 and 7.0, the polishing process may be used to remove a silicon dioxide layer from the topography at a faster rate than a silicon nitride layer residing beneath the oxide layer. Alternately, a metal may be selectively removed from above an oxide layer if the polishing liquid has a pH between 2.0 and 5.0. In another embodiment, the liquid may be deionized water. The water does not react with the material being polished.
    Type: Grant
    Filed: January 17, 2001
    Date of Patent: March 26, 2002
    Assignee: Cypress Semiconductor Corp.
    Inventors: Anantha R. Sethuraman, William W. C. Koutny, Jr.
  • Patent number: 6302766
    Abstract: The present invention provides a method for cleaning particles from a semiconductor topography that has been polished using a fixed-abrasive polishing process by applying a cleaning solution including either (a) an acid and a peroxide or (b) an acid oxidant to the topography. According to an embodiment, a semiconductor topography is polished by a fixed-abrasive process in which the topography is pressed face-down on a rotating polishing pad having particles embedded in the pad while a liquid absent of particulate matter is dispensed onto the pad. The particles may include, e.g., cerium oxide, cerium dioxide, &agr;alumina, &ggr;alumina, silicon dioxide, titanium oxide, chromium oxide, or zirconium oxide. A cleaning solution comprising either (a) an acid and a peroxide, e.g., hydrogen peroxide, or (b) an acid oxidant is applied to the semiconductor topography after the polishing process is completed.
    Type: Grant
    Filed: September 13, 1999
    Date of Patent: October 16, 2001
    Assignee: Cypress Semiconductor Corp.
    Inventors: Anantha R. Sethuraman, William W. C. Koutny, Jr.
  • Patent number: 6232231
    Abstract: The present invention advantageously provides a substantially planarized semiconductor topography and method for making the same by forming a plurality of dummy features in a dielectric layer between a relatively wide interconnect and a series of relatively narrow interconnect. According to an embodiment, a plurality of laterally spaced dummy trenches are first etched in the dielectric layer between a relatively wide trench and a series of relatively narrow trenches. The dummy trenches, the wide trench, and the narrow trenches are filled with a conductive material, e.g., a metal. The conductive material is deposited to a level spaced above the upper surface of the dielectric layer. The surface of the conductive material is then polished to a level substantially coplanar with that of the upper surface of the dielectric layer. Advantageously, the polish rate of the conductive material above the dummy trenches and the wide and narrow trenches is substantially uniform.
    Type: Grant
    Filed: August 31, 1998
    Date of Patent: May 15, 2001
    Assignee: Cypress Semiconductor Corporation
    Inventors: Anantha R. Sethuraman, Christopher A. Seams
  • Patent number: 6218305
    Abstract: A method is provided for polishing a composite comprised of silica and silicon nitride wherein a polishing composition is used comprising: an aqueous medium, abrasive particles, a surfactant, an organic polymer viscosity modifier which increases the viscosity of the composition, and a compound which complexes with the silica and silicon nitride wherein the complexing agent has two or more functional groups each having a dissociable proton, the functional groups being the same or different.
    Type: Grant
    Filed: May 25, 2000
    Date of Patent: April 17, 2001
    Assignee: Rodel Holdings, Inc.
    Inventors: Sharath D. Hosali, Anantha R. Sethuraman, Jiun-Fang Wang, Lee Melbourne Cook, Michael R. Oliver
  • Patent number: 6200896
    Abstract: The present invention advantageously provides a method and apparatus for polishing a semiconductor topography by applying a liquid which is void of particles between the topography and an abrasive polishing pad surface. The semiconductor topography is rotated relative to the polishing surface to polish elevationally raised regions of the topography. The particles are fixed within the polishing surface which may comprise a polymeric material. In one embodiment, the liquid may comprise water diluted with acid. If the liquid is adjusted to have a pH between 6.0 and 7.0, the polishing process may be used to remove a silicon dioxide layer from the topography at a faster rate than a silicon nitride layer residing beneath the oxide layer. Alternately, a metal may be selectively removed from above an oxide layer if the polishing liquid has a pH between 2.0 and 5.0. In another embodiment, the liquid may be deionized water. The water does not react with the material being polished.
    Type: Grant
    Filed: January 22, 1998
    Date of Patent: March 13, 2001
    Assignee: Cypress Semiconductor Corporation
    Inventors: Anantha R. Sethuraman, William W. C. Koutny, Jr.
  • Patent number: 6132637
    Abstract: A composition is provided for polishing a composite comprised of silica and silicon nitride comprising: an aqueous medium, abrasive particles, a surfactant, and a compound which complexes with the silica and silicon nitride wherein the complexing agent has two or more functional groups each having a dissociable proton, the functional groups being the same or different.
    Type: Grant
    Filed: May 1, 1998
    Date of Patent: October 17, 2000
    Assignee: Rodel Holdings, Inc.
    Inventors: Sharath D. Hosali, Anantha R. Sethuraman, Jiun-Fang Wang, Lee Melbourne Cook, Michael R. Oliver
  • Patent number: 6042741
    Abstract: A composition is provided for polishing a composite comprised of silica and silicon nitride comprising: an aqueous medium, abrasive particles, a surfactant, and a compound which complexes with the silica and silicon nitride wherein the complexing agent has two or more functional groups each having a dissociable proton, the functional groups being the same or different.
    Type: Grant
    Filed: March 10, 1998
    Date of Patent: March 28, 2000
    Assignee: Rodel Holdings, Inc.
    Inventors: Sharath D. Hosali, Anantha R. Sethuraman, Jiun-Fang Wang, Lee Melbourne Cook
  • Patent number: 6001269
    Abstract: A process is provided for polishing a composite comprised of an insulating layer, a metal and titanium in which the composite is polished in a standard polishing machine using an aqueous slurry comprising submicron abrasive particles, an iodate, and a peroxide. Another process is provided in which peroxide is added to the aqueous slurry only when a titanium or titanium nitride layer is being polished. Further the invention also comprises the addition of a base to the slurry stream exiting the polishing machine to bring the pH of the used slurry to about 7 or higher.
    Type: Grant
    Filed: May 20, 1997
    Date of Patent: December 14, 1999
    Assignee: Rodel, Inc.
    Inventors: Anantha R. Sethuraman, Lee Melbourne Cook, Huey-Ming Wang, Guangwei Wu
  • Patent number: 5972124
    Abstract: The present invention provides a method for cleaning particles from a semiconductor topography that has been polished using a fixed-abrasive polishing process by applying a cleaning solution including either (a) an acid and a peroxide or (b) an acid oxidant to the topography. According to an embodiment, a semiconductor topography is polished by a fixed-abrasive process in which the topography is pressed face-down on a rotating polishing pad having particles embedded in the pad while a liquid absent of particulate matter is dispensed onto the pad. The particles may include, e.g., cerium oxide, cerium dioxide, .alpha. alumina, .gamma. alumina, silicon dioxide, titanium oxide, chromium oxide, or zirconium oxide. A cleaning solution including either (a) an acid and a peroxide, e.g., hydrogen peroxide, or (b) an acid oxidant is applied to the semiconductor topography after the polishing process is completed.
    Type: Grant
    Filed: August 31, 1998
    Date of Patent: October 26, 1999
    Assignee: Advanced Micro Devices, Inc.
    Inventors: Anantha R. Sethuraman, William W. C. Koutny, Jr.
  • Patent number: 5756398
    Abstract: An aqueous slurry is provided which is useful for the chemical-mechanical polishing of substrates containing titanium comprising: water, submicron abrasive particles, an oxidizing agent, and a combination of complexing agents comprising a phthalate compound and a compound which is a di- or tri-carboxylic acid with at least one hydroxyl group in an alpha position relative to one of the carboxyl groups.
    Type: Grant
    Filed: March 17, 1997
    Date of Patent: May 26, 1998
    Assignee: Rodel, Inc.
    Inventors: Jiun-Fang Wang, Anantha R. Sethuraman, Lee Melbourne Cook
  • Patent number: 5738800
    Abstract: A composition is provided for polishing a composite comprised of silica and silicon nitride comprising: an aqueous medium, abrasive particles, a surfactant, and a compound which complexes with the silica and silicon nitride wherein the complexing agent has has two or more functional groups each having a dissociable proton, the functional groups being the same or different.
    Type: Grant
    Filed: February 19, 1997
    Date of Patent: April 14, 1998
    Assignee: Rodel, Inc.
    Inventors: Sharath D. Hosali, Anantha R. Sethuraman, Jiun-Fang Wang, Lee Melbourne Cook