Patents by Inventor Christopher L. Chua

Christopher L. Chua 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: 6621141
    Abstract: Patterned ground planes are formed between out-of-plane microcoil structures and underlying integrated circuits (ICs). Each out-of-plane coil includes a series of loops extending from base (contact) pads formed on a dielectric layer (e.g., thick IC passivation, or BCB formed on thin passivation). Losses due to capacitive coil-to-substrate coupling are minimized using a central ground plane structure located under the base pads of the microcoil. Magnetic losses are reduced by forming a low-resistance ground plane structure including end portions located outside of the ends of the microcoil. The low-resistance ground plane can be slotted to reduce the loop size of eddy current pathways. The low-resistance ground plane is formed from one or more of the top IC metal layers, copper pads formed between the IC passivation and the dielectric, portions of the metal used to form the microcoil, or combinations thereof.
    Type: Grant
    Filed: July 22, 2002
    Date of Patent: September 16, 2003
    Assignee: Palo Alto Research Center Incorporated
    Inventors: Koenraad F. Van Schuylenbergh, Christopher L. Chua, David K. Fork
  • Patent number: 6606235
    Abstract: A new type of high-Q variable capacitor includes a substrate, a first electrically conductive layer fixed to the substrate, a dielectric layer fixed to a portion of the electrically conductive layer, and a second electrically conductive layer having an anchor portion and a free portion. The anchor portion is fixed to the dielectric layer and the free portion is initially fixed to the dielectric layer, but is released from the dielectric layer to become separated from the dielectric layer, and wherein an inherent stress profile in the second electrically conductive layer biases the free portion away from the a dielectric layer. When a bias voltage is applied between the first electrically conductive layer and the second electrically conductive layer, electrostatic forces in the free portion bend the free portion towards the first electrically conductive layer, thereby increasing the capacitance of the capacitor.
    Type: Grant
    Filed: May 23, 2002
    Date of Patent: August 12, 2003
    Inventors: Christopher L. Chua, Eric Peeters, Koenraad F. Van Schuylenbergh, Donald L. Smith
  • Patent number: 6582989
    Abstract: An out-of-plane micro-structure which can be used for on-chip integration of high-Q inductors and transformers places the magnetic field direction parallel to the substrate plane without requiring high aspect ratio processing. The photolithographically patterned coil structure includes an elastic member having an intrinsic stress profile. The intrinsic stress profile biases a free portion away from the substrate forming a loop winding. An anchor portion remains fixed to the substrate. The free portion end becomes a second anchor portion which may be connected to the substrate via soldering or plating. Alternately, the loop winding can be formed of two elastic members in which the free ends are joined in mid-air. A series of individual coil structures can be joined via their anchor portions to form inductors and transformers.
    Type: Grant
    Filed: December 7, 2001
    Date of Patent: June 24, 2003
    Assignee: Xerox Corporation
    Inventors: David K. Biegelsen, Christopher L. Chua, David K. Fork
  • Patent number: 6567448
    Abstract: A III-V compound light emitter is integrated with Si-based actuators. The proposed devices take advantage of the superior optical properties of III-V compounds and the superior mechanical properties of Si, as well as mature fabrication technologies of Si-Micro-Electro-Mechanical Systems (MEMS). The emitter can be a light emitting diode (LED), a vertical cavity surface emitting laser (VCSEL) or an edge emitting laser.
    Type: Grant
    Filed: December 11, 1998
    Date of Patent: May 20, 2003
    Assignee: Xerox Corporation
    Inventors: Decai Sun, Ross D. Bringans, Christopher L. Chua, Philip D. Floyd, Eric Peeters, Joel A. Kubby, Alex T. Tran
  • Patent number: 6549691
    Abstract: An optical cross switch including an improved system to align optical components is described. The system utilizes a highly transmissive sensor positioned in the optical path of an optical signal to determine the precise position of the optical signal. A feedback loop uses output from the highly transmissive sensor to readjust elements that maintains the optical signal in a desired position. The current system is particularly suitable for use in an optical cross switch.
    Type: Grant
    Filed: November 8, 2000
    Date of Patent: April 15, 2003
    Assignee: Xerox Corporation
    Inventors: Robert A. Street, Eric Peeters, Michel A. Rosa, Jeng Ping Lu, Christopher L. Chua
  • Patent number: 6548908
    Abstract: A passive semiconductor device structure is made using planar lateral oxidation to define a buried oxidized semiconductor structure such as a passive waveguide, microlens or DBR mirror stack.
    Type: Grant
    Filed: December 27, 1999
    Date of Patent: April 15, 2003
    Assignee: Xerox Corporation
    Inventors: Christopher L. Chua, Philip D. Floyd, Thomas L. Paoli, Decai Sun
  • Publication number: 20030067009
    Abstract: Semiconductor devices in an optoelectronic integrated circuit are electrically isolated from each other by using planar lateral oxidation to oxidize a buried semiconductor layer vertically separating the semiconductor devices.
    Type: Application
    Filed: October 25, 2002
    Publication date: April 10, 2003
    Applicant: Xerox Corporation
    Inventors: Christopher L. Chua, Philip D. Floyd, Thomas L. Paoli, Decai Sun
  • Patent number: 6545335
    Abstract: Semiconductor devices in an optoelectronic integrated circuit are electrically isolated from each other by using planar lateral oxidation to oxidize a buried semiconductor layer vertically separating the semiconductor devices.
    Type: Grant
    Filed: December 27, 1999
    Date of Patent: April 8, 2003
    Assignee: Xerox Corporation
    Inventors: Christopher L. Chua, Philip D. Floyd, Thomas L. Paoli, Decai Sun
  • Publication number: 20030057533
    Abstract: A hybrid structure or device is provided wherein carried on a single substrate is at least one micro-spring interconnect having an elastic material that is initially fixed to a surface of the substrate, an anchor portion which is fixed to the substrate surface and a free portion. The spring contact is self-assembling in that as the free portion is released it moves out of the plane of the substrate. Also integrated on the substrate is a sensor having an active layer and contacts. The substrate and sensor may be formed of materials which are somewhat partially transparent to light at certain infrared wavelengths. The integrated sensor/spring contact configuration may be used in an imaging system to sense output from a light source which is used for image formation. The light source may be a laser array, LED array or other appropriate light source. The sensor is appropriately sized to sense all or some part of light from the light source.
    Type: Application
    Filed: December 21, 1999
    Publication date: March 27, 2003
    Inventors: FRANCESCO LEMMI, CHRISTOPHER L. CHUA, PING MEI, JENGPING LU, DAVID K. FORK, HARRY J. MCINTYRE
  • Patent number: 6534249
    Abstract: Several methods and structures for improving the yield of out-of-plane micro-device structures including springs and coils are described. Structures and methods for adjusting the coil diameter after spring release, if necessary, are also disclosed. In one method the radius of curvature of the released elastic members is controlled by depositing a layer of a reflow material and reflowing the layer after release. The high yield structures may be used in numerous electronic applications such as filter circuits.
    Type: Grant
    Filed: February 9, 2001
    Date of Patent: March 18, 2003
    Assignee: Xerox Corporation
    Inventors: David K. Fork, Christopher L. Chua
  • Publication number: 20030030965
    Abstract: A new type of high-Q variable capacitor includes a substrate, a first electrically conductive layer fixed to the substrate, a dielectric layer fixed to a portion of the electrically conductive layer, and a second electrically conductive layer having an anchor portion and a free portion. The anchor portion is fixed to the dielectric layer and the free portion is initially fixed to the dielectric layer, but is released from the dielectric layer to become separated from the dielectric layer, and wherein an inherent stress profile in the second electrically conductive layer biases the free portion away from the a dielectric layer. When a bias voltage is applied between the first electrically conductive layer and the second electrically conductive layer, electrostatic forces in the free portion bend the free portion towards the first electrically conductive layer, thereby increasing the capacitance of the capacitor.
    Type: Application
    Filed: May 23, 2002
    Publication date: February 13, 2003
    Applicant: Xerox Corporation
    Inventors: Christopher L. Chua, Eric Peeters, Koenraad F. Van Schuylenbergh, Donald L. Smith
  • Publication number: 20030027081
    Abstract: An out-of-plane micro-structure which can be used for on-chip integration of high-Q inductors and transformers places the magnetic field direction parallel to the substrate plane without requiring high aspect ratio processing. The photolithographically patterned coil structure includes an elastic member having an intrinsic stress profile. The intrinsic stress profile biases a free portion away from the substrate forming a loop winding. An anchor portion remains fixed to the substrate. The free portion end becomes a second anchor portion which may be connected to the substrate via soldering or plating. A series of individual coil structures can be joined via their anchor portions to form inductors and transformers.
    Type: Application
    Filed: May 23, 2002
    Publication date: February 6, 2003
    Applicant: Xerox Corporation
    Inventors: Christopher L. Chua, Francesco Lemmi, Koenraad F. Van Schuylenbergh, Jeng Ping Lu, David K. Fork, Eric Peeters, Decai Sun, Donald L. Smith, Linda T. Romano
  • Publication number: 20030010615
    Abstract: Efficient methods are disclosed for fabricating spring structures in which a passive, conductive coating is deposited onto the spring structure after release. A release layer is deposited on a substrate and then a spring metal layer is formed thereon. A first mask is then used to etch the spring metal layer to form a spring metal finger. A second (release) mask is then deposited that defines a release window used to remove a portion of the release layer and release a free end of the spring metal finger. The second mask is also used as a mask during the subsequent directional deposition of a conductive coating material on the cantilevered tip of the finger. The second mask is then stripped, and the residual coating deposited thereon is lifted off. The resulting spring structure includes conductive coating on the upper surface and front edge of the finger tip.
    Type: Application
    Filed: July 11, 2001
    Publication date: January 16, 2003
    Applicant: Xerox Corporation
    Inventors: David K. Fork, Christopher L. Chua
  • Publication number: 20020187662
    Abstract: An out-of-plane micro-structure which can be used for on-chip integration of high-Q inductors and transformers places the magnetic field direction parallel to the substrate plane without requiring high aspect ratio processing. The photolithographically patterned coil structure includes an elastic member having an intrinsic stress profile. The intrinsic stress profile biases a free portion away from the substrate forming a loop winding. An anchor portion remains fixed to the substrate. The free portion end becomes a second anchor portion which may be connected to the substrate via soldering or plating. Alternately, the loop winding can be formed of two elastic members in which the free ends are joined in mid-air. A series of individual coil structures can be joined via their anchor portions to form inductors and transformers.
    Type: Application
    Filed: May 20, 2002
    Publication date: December 12, 2002
    Applicant: Xerox Corporation
    Inventors: David K. Biegelsen, Christopher L. Chua, David K. Fork
  • Patent number: 6455340
    Abstract: A method is provided for fabricating a nitride based resonant cavity semiconductor structure with a first distributed Bragg reflector on a sapphire substrate, a second substrate bonded to the first distributed Bragg reflector, the sapphire substrate removed by laser-assisted epitaxial lift-off, and fabricating a second Bragg reflector on the semiconductor structure opposite the first distributed Bragg reflector. The nitride based resonant cavity semiconductor structure can be a VCSEL, LED or photodetector, or a combination of said devices.
    Type: Grant
    Filed: December 21, 2001
    Date of Patent: September 24, 2002
    Assignee: Xerox Corporation
    Inventors: Christopher L. Chua, Michael A. Kneissl, David P. Bour
  • Publication number: 20020125980
    Abstract: An out-of-plane micro-structure which can be used for on-chip integration of high-Q inductors and transformers places the magnetic field direction parallel to the substrate plane without requiring high aspect ratio processing. The photolithographically patterned coil structure includes an elastic member having an intrinsic stress profile. The intrinsic stress profile biases a free portion away from the substrate forming a loop winding. An anchor portion remains fixed to the substrate. The free portion end becomes a second anchor portion which may be connected to the substrate via soldering or plating. Alternately, the loop winding can be formed of two elastic members in which the free ends are joined in mid-air. A series of individual coil structures can be joined via their anchor portions to form inductors and transformers.
    Type: Application
    Filed: December 7, 2001
    Publication date: September 12, 2002
    Applicant: Xerox Corporation
    Inventors: David K. Biegelsen, Christopher L. Chua, David K. Fork
  • Patent number: 6439898
    Abstract: A method and apparatus for interconnecting at least two devices. Each of the interconnected devices includes a contact structure for electrically and/or physically interconnecting the devices. Preferably, the contact structure for at least one of the devices includes a spring contact. An adhesive, such as a UV-curable adhesive, is applied to at least a portion of one of the devices, and once the adhesive is applied, the devices are assembled, i.e., brought into sufficient proximity so that the contact structures interconnect the devices. The adhesive can be applied directly to contact structures of one of the devices and/or can be applied to other portions of the devices so that the adhesive flows around the contact structures during assembly. The adhesive is then cured to bond the devices together.
    Type: Grant
    Filed: February 28, 2001
    Date of Patent: August 27, 2002
    Assignee: Xerox Corporation
    Inventors: Christopher L. Chua, David K. Fork, Patrick G. Kim, Linda Romano
  • Publication number: 20020110761
    Abstract: Several methods and structures for improving the yield of out-of-plane micro-device structures including springs and coils are described. In one method the elastic members have graded perforations for controlling rate of release. In another method and structure, a layout enables the contact landing area to be increased. The high yield structures may be used in numerous electronic applications such as filter circuits.
    Type: Application
    Filed: February 9, 2001
    Publication date: August 15, 2002
    Applicant: Xerox Corporation
    Inventors: David K. Fork, Christopher L. Chua, Koenraad F. Van Schuylenbergh, Noble M. Johnson, David K. Biegelsen
  • Publication number: 20020110758
    Abstract: Several methods and structures for improving the yield of out-of-plane micro-device structures including springs and coils are described. Structures and methods for adjusting the coil diameter after spring release, if necessary, are also disclosed. In one method the radius of curvature of the released elastic members is controlled by depositing a layer of a reflow material and reflowing the layer after release. The high yield structures may be used in numerous electronic applications such as filter circuits.
    Type: Application
    Filed: February 9, 2001
    Publication date: August 15, 2002
    Applicant: Xerox Corporation
    Inventors: David K. Fork, Christopher L. Chua
  • Patent number: 6429417
    Abstract: A system to align optical components is described. The system utilizes a highly transmissive sensor positioned in the optical path of an optical signal to determine the precise position of the optical signal. A feedback loop uses output from the highly transmissive sensor to readjust elements that maintains the optical signal in a desired position. The current system is particularly suitable for use in an optical cross switch.
    Type: Grant
    Filed: November 8, 2000
    Date of Patent: August 6, 2002
    Assignee: Xerox Corporation
    Inventors: Robert A. Street, Eric Peeters, Michel A. Rosa, Jeng Ping Lu, Christopher L. Chua