Patents by Inventor Subramoney V. Iyer

Subramoney V. Iyer 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: 6146250
    Abstract: Vibrating and oscillating rates can be dynamically changed during polishing to achieve an optimal polishing process. A semiconductor device substrate (34) has a first layer with a first film (12) and a second film (10) that overlies the first film (12), where the first film (12) is harder and underlies the second film (10). In one embodiment, the substrate (34) is placed over a first region (66) of a polishing pad (60). The second film (10) is polished at a first vibrating and oscillating rates over the first region (66). An endpoint signal is received when the first film (12) is reached. The substrate (34) is moved to a second region (62) of the polishing pad (60) that is closer to the edge of the pad and has a higher feature density compared to the first region (66). Polishing is performed at a second vibrating and oscillating rates that are different from the first vibrating and oscillating rates to remove the first film (10).
    Type: Grant
    Filed: July 15, 1999
    Date of Patent: November 14, 2000
    Assignee: Motorola, Inc.
    Inventors: Rajan Nagabushnam, Subramoney V. Iyer
  • Patent number: 6012970
    Abstract: Vibrating and oscillating rates can be dynamically changed during polishing to achieve an optimal polishing process. A semiconductor device substrate (34) has a first layer with a first film (12) and a second film (10) that overlies the first film (12), where the first film (12) is harder and underlies the second film (10). In one embodiment, the substrate (34) is placed over a first region (66) of a polishing pad (60). The second film (10) is polished at a first vibrating and oscillating rates over the first region (66). An endpoint signal is received when the first film (12) is reached. The substrate (34) is moved to a second region (62) of the polishing pad (60) that is closer to the edge of the pad and has a higher feature density compared to the first region (66). Polishing is performed at a second vibrating and oscillating rates that are different from the first vibrating and oscillating rates to remove the first film (10).
    Type: Grant
    Filed: January 15, 1997
    Date of Patent: January 11, 2000
    Assignee: Motorola, Inc.
    Inventors: Rajan Nagabushnam, Subramoney V. Iyer
  • Patent number: 6001726
    Abstract: A method for forming a contact structure (10) which enables the use of ultra-shallow source/drain junctions begins by forming source and drain regions (14) and gate electrode (16). The source and drain regions (14) and the gate electrode (16) are silicided to form silicide regions (20). A conductive tungsten nitride etch stop layer (22) is formed overlying the silicide regions (20). Contact plug regions (28) are then formed to contact to the etch stop layer (22) and silicided regions (20). At this point, all of the silicide regions (20) are electrically short circuited. To remove this electric short circuit, an isotropic etch process comprising hydrogen peroxide, ammonium hydroxide, and water is used to remove portions of the tungsten nitride regions which are between the individual contact portions (28) in a self-aligned manner.
    Type: Grant
    Filed: March 24, 1997
    Date of Patent: December 14, 1999
    Assignee: Motorola, Inc.
    Inventors: Rajan Nagabushnam, Rajeev Bajaj, Ram Venkataraman, Shyam Mattay, Subramoney V. Iyer
  • Patent number: 5665202
    Abstract: A process for polish planarizing a fill material (40) overlying a semiconductor substrate (30) includes a multi-step polishing process. In one embodiment, a second planarization layer (42) is deposited over a fill material (40) and a portion of the fill material (40) is removed leaving a remaining portion (44). The pad pressure of a CMP apparatus (20) is adjusted such that a first pressure is generated during the polishing process. Then, the remaining portion (44) is removed, while operating the CMP apparatus (20) at a second pad pressure. The selectivity of the polishing process is maintained by reducing the pad pressure during the second polishing step. In a second embodiment, after the first polishing step is performed, the remaining portion (44) is removed by an etching process using a portion (46) of second planarization layer (42).
    Type: Grant
    Filed: November 24, 1995
    Date of Patent: September 9, 1997
    Assignee: Motorola, Inc.
    Inventors: Chitra K. Subramanian, Asanga H. Perera, James D. Hayden, Subramoney V. Iyer