Patents by Inventor Seyed Jafar Jafarian-Tehrani

Seyed Jafar Jafarian-Tehrani 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).

  • Publication number: 20040061448
    Abstract: A method tests a plasma processing system having a chamber, an RF power source, and a matching network. An RF power signal is generated from the RF power source to the chamber without igniting any plasma within the chamber. The voltage of the RF power signal, the current of the RF power signal, and the phase of the RF power signal, received by the chamber is measured while holding other parameters affecting the chamber constant. A value representative of an impedance of the chamber is computed based on the voltage, the current, and the phase. The value is then compared with a reference value to determine any defects in the plasma processing system. The reference value is representative of the impedance of a defect-free chamber.
    Type: Application
    Filed: January 13, 2003
    Publication date: April 1, 2004
    Applicant: Lam Research Corporation, a Delaware Corporation
    Inventors: Armen Avoyan, Seyed Jafar Jafarian-Tehrani
  • Patent number: 6563076
    Abstract: A plasma reactor system with controlled DC bias for manufacturing semiconductor wafers and the like. The reactor system includes a plasma chamber, a plasma generating coil and a chuck including a chuck electrode. The chuck supports a workpiece within the chamber. The plasma reactor system further includes a pair of generators, one of which supplies a radio frequency signal to the plasma generating coil. The second generator delivers a RF signal which to the chuck electrode and acts to control DC bias at the workpiece. Peak voltage sensor circuitry and set point signal circuitry controls the power output of the generator, and a matching network coupled between the generator and the first electrode matches the impedance of the RF signal with the load applied by the plasma. DC bias determines the energy with which plasma particles impact the surface of a workpiece and thereby determines the rate at which the process is performed.
    Type: Grant
    Filed: April 25, 2000
    Date of Patent: May 13, 2003
    Assignee: Lam Research Corporation
    Inventors: Neil Benjamin, Scott Baldwin, Seyed Jafar Jafarian-Tehrani
  • Patent number: 6509542
    Abstract: A plasma reactor system with controlled DC bias for manufacturing semiconductor wafers and the like. The reactor system includes a plasma chamber, a plasma generating coil and a chuck including a chuck electrode. The chuck supports a workpiece within the chamber. The plasma reactor system further includes a pair of generators, one of which supplies a radio frequency signal to the plasma generating coil. The second generator delivers a RF signal which to the chuck electrode and acts to control DC bias at the workpiece. Peak voltage sensor circuitry and set point signal circuitry controls the power output of the generator, and a matching network coupled between the generator and the first electrode matches the impedance of the RF signal with the load applied by the plasma. DC bias determines the energy with which plasma particles impact the surface of a workpiece and thereby determines the rate at which the process is performed.
    Type: Grant
    Filed: April 25, 2000
    Date of Patent: January 21, 2003
    Assignee: LAM Research Corp.
    Inventors: Neil Benjamin, Scott Baldwin, Seyed Jafar Jafarian-Tehrani
  • Patent number: 5824606
    Abstract: A method in a plasma processing system for modifying a phase difference between a first radio frequency (RF) signal and a second RF signal. The first RF signal is supplied by a first RF power source to a first electrode and the second RF signal is supplied by a second RF power source to a second electrode of a plasma processing system. The second RF power source is coupled to the first RF power source as a slave RF power source in a master-and-slave configuration. The method includes the step of ascertaining a phase difference between a phase of the first RF signal and a phase of the second RF signal. The method further includes the step of comparing the phase difference with a phase control set point signal to output a control signal to the second RF power source, whereby the second RF power source, responsive to the control signal, modifies the phase of the second RF signal to cause the phase difference to approximate a phase difference value represented by the phase control set point signal.
    Type: Grant
    Filed: March 29, 1996
    Date of Patent: October 20, 1998
    Assignee: Lam Research Corporation
    Inventors: Robert D. Dible, Stephen G. Bradley, Seyed Jafar Jafarian-Tehrani
  • Patent number: 5812361
    Abstract: An electrostatic chuck system having an electrostatic chuck for securely holding a wafer on a surface of the electrostatic chuck. The electrostatic chuck system comprises a wafer bias sensor coupled to a first portion of the electrostatic chuck for sensing an alternating current signal at the first portion. The wafer bias sensor outputs, responsive to the alternating current signal, a direct current voltage level representative of a direct current bias level of the wafer. The electrostatic chuck system further comprises a variable electrostatic chuck power supply coupled to the wafer bias sensor. The variable electrostatic chuck power supply provides a first potential level to the first portion of the electrostatic chuck.
    Type: Grant
    Filed: March 29, 1996
    Date of Patent: September 22, 1998
    Assignee: Lam Research Corporation
    Inventors: Phillip Lawrence Jones, Seyed Jafar Jafarian-Tehrani, Boris V. Atlas, David R-Chen Liu, Ken Edward Tokunaga, Ching-Hwa Chen
  • Patent number: 5708250
    Abstract: An r.f. excited vacuum plasma processor has a workpiece held in place by a monopolar or bipolar electrostatic chuck having an electrode that develops peak r.f. voltages over a wide amplitude range. A chuck DC power supply source is connected to the chuck. An r.f. peak detecting circuit coupled with the electrode is part of a circuit for controlling the DC voltage applied by the chuck power supply to the chuck. The control circuit supplies an unamplified replica of a DC voltage derived by the peak detecting circuit to the chuck DC power supply source via a DC circuit including only passive elements so the level of the DC voltage applied to the chuck varies in response to variations in the peak amplitude of the r.f. voltage. The peak detector includes at least several series connected diodes having electrodes polarized in the same direction or two stacks of series connected diodes.
    Type: Grant
    Filed: March 29, 1996
    Date of Patent: January 13, 1998
    Assignee: Lam Resarch Corporation
    Inventors: Neil Benjamin, Seyed Jafar Jafarian-Tehrani, Max Artusy