Patents by Inventor Ratan K. Choudhury

Ratan K. Choudhury 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: 6303995
    Abstract: Disclosed is an integrated circuit structure having one or more metal lines thereon with metal line sidewall retention structures formed on the sides of the metal lines. The metal line sidewall retention structures comprise a material sufficiently hard to inhibit lateral distortion or expansion of portions of the metal line during subsequent processing or use of the metal line. The metal line sidewall retention structures are formed by anisotropically etching a layer of a material sufficiently hard to inhibit lateral distortion or expansion of portions of the metal line after formation of a layer of such a material over and around the sides of the metal lines.
    Type: Grant
    Filed: January 11, 1996
    Date of Patent: October 16, 2001
    Assignee: LSI Logic Corporation
    Inventors: Ashok K. Kapoor, Ratan K. Choudhury
  • Patent number: 6109775
    Abstract: Disclosed is the formation of additional lines, either dummy lines or active lines, in an electrically conductive pattern of lines to provide more uniform loading for either etching or chemical/mechanical polishing of a layer of electrically conductive material from which the pattern of lines is formed. Also disclosed is the use of additional or dummy vias to balance the loading during etching of the vias, as well as to provide stress relief for underlying metal in regions or areas having a low density of vias. Further disclosed is the use of a working grid on the integrated circuit structure to analyze the spacing of lines or vias for the above effects.
    Type: Grant
    Filed: September 8, 1997
    Date of Patent: August 29, 2000
    Assignee: LSI Logic Corporation
    Inventors: Prabhakar P. Tripathi, Keith Chao, Ratan K. Choudhury, Gauri C. Das, Nicholas K. Eib, Ashok K. Kapoor, Thomas G. Mallon
  • Patent number: 5789783
    Abstract: A first metal layer is formed on a substrate of an integrated circuit and electrically interconnects a microelectronic device and an Input/Output (I/O) pad. A second metal layer is insulated from the first metal layer by a dielectric layer, and is connected directly only to the pad. A plurality of vias are formed through the dielectric layer, and electrically interconnect the first and second metal layers such that current can flow between the device and the pad through both metal layers and the vias. A higher scale of circuit integration is made possible by reducing the widths of the metal layers without reducing their combined current carrying capacity. An Electrostatic Discharge (ESD) protection device is connected to one or both of the first and second metal layers such that current can flow from the pad to the protection device during an ESD event through both metal layers and the vias.
    Type: Grant
    Filed: April 2, 1996
    Date of Patent: August 4, 1998
    Assignee: LSI Logic Corporation
    Inventors: Ratan K. Choudhury, Ashok K. Kapoor, Satish Menon
  • Patent number: 5614437
    Abstract: A method for manufacturing an ohmic contact on a semiconductor device, as disclosed herein, includes a first step of etching a via through a non-conductive layer formed over a partially fabricated version of the semiconductor device. This step exposes a region of a device element such as a source, gate electrode, etc. Next, an ohmic contact layer including tantalum and silicon is deposited over the partially fabricated device and in the vias by sputtering in an argon atmosphere. Thereafter, and in the same processing apparatus, a barrier layer including a tantalum silicon nitride is deposited over the ohmic contact layer. Then an aluminum alloy metallization layer is directly deposited on the partially fabricated device at a temperature of at least 650.degree. C. At this deposition temperature, the metallization layer conformally fills the via, thereby producing a stable, uniform contact.
    Type: Grant
    Filed: January 26, 1995
    Date of Patent: March 25, 1997
    Assignee: LSI Logic Corporation
    Inventor: Ratan K. Choudhury
  • Patent number: 5525837
    Abstract: A method for manufacturing an ohmic contact on a semiconductor device, as disclosed herein, includes a first step of etching a via through a non-conductive layer formed over a partially fabricated version of the semiconductor device. This step exposes a region of a device element such as a source, gate electrode, etc. Next, an ohmic contact layer including tantalum and silicon is deposited over the partially fabricated device and in the vias by sputtering in an argon atmosphere. Thereafter, and in the same processing apparatus, a barrier layer including a tantalum silicon nitride is deposited over the ohmic contact layer. Then an aluminum alloy metallization layer is directly deposited on the partially fabricated device at a temperature of at least 650.degree. C. At this deposition temperature, the metallization layer conformally fills the via, thereby producing a stable, uniform contact.
    Type: Grant
    Filed: June 5, 1995
    Date of Patent: June 11, 1996
    Assignee: LSI Logic Corporation
    Inventor: Ratan K. Choudhury