Patents by Inventor Ilwoong Koo

Ilwoong Koo 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: 9783884
    Abstract: Methods of decreasing the dose per pulse implanted into a workpiece disposed in a process chamber are disclosed. According to one embodiment, the plasma is generated by a RF power supply. This RF power supply may have two different modes, a first, referred to as continuous wave mode, where the RF power supply is continuously outputting a voltage. This mode allows creation of the plasma within the process chamber. During the second mode, referred to as pulsed plasma mode, the RF power supply outputs two different power levels. The platen bias voltage may be a more negative value when the lower RF power level is being applied. This pulsed (or multi-setpoint) plasma also assists in reducing dopant deposition on the wafer during the time when CW plasma is on but the bias voltage pulse is in the off-state. In a further embodiment, a delay is introduced between the transition to the pulsed plasma mode and the initiation of the implanting process.
    Type: Grant
    Filed: February 28, 2014
    Date of Patent: October 10, 2017
    Assignee: Varian Semiconductor Equipment Associates, Inc.
    Inventors: Ilwoong Koo, Jun Lee, Aseem K. Srivastava
  • Patent number: 9142438
    Abstract: Methods of clamping and declamping a wafer from a platen are disclosed. The platen comprises one or more electrodes, which are electrically biased to electrostatically clamp the wafer to the platen. The electrode is biased to a first voltage where the wafer may be processed. Thereafter, one or more voltages are subsequently applied to the electrodes. In some embodiments, each subsequent voltage is less than the previously applied voltage. In other embodiments, one or more of the subsequent voltages may be greater than the previously applied voltage. This sequence of voltage may reduce the likelihood that the wafer will stick or adhere to the platen during the removal process.
    Type: Grant
    Filed: April 29, 2013
    Date of Patent: September 22, 2015
    Assignee: Varian Semiconductor Equipment Associates, Inc.
    Inventors: Ilwoong Koo, Sung-Hwan Hyun
  • Publication number: 20140272182
    Abstract: Methods of decreasing the dose per pulse implanted into a workpiece disposed in a process chamber are disclosed. According to one embodiment, the plasma is generated by a RF power supply. This RF power supply may have two different modes, a first, referred to as continuous wave mode, where the RF power supply is continuously outputting a voltage. This mode allows creation of the plasma within the process chamber. During the second mode, referred to as pulsed plasma mode, the RF power supply outputs two different power levels. The platen bias voltage may be a more negative value when the lower RF power level is being applied. This pulsed (or multi-setpoint) plasma also assists in reducing dopant deposition on the wafer during the time when CW plasma is on but the bias voltage pulse is in the off-state. In a further embodiment, a delay is introduced between the transition to the pulsed plasma mode and the initiation of the implanting process.
    Type: Application
    Filed: February 28, 2014
    Publication date: September 18, 2014
    Inventors: Ilwoong Koo, Jun Lee, Aseem K. Srivastava