Patents by Inventor Chuan Cheah

Chuan Cheah 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: 20140084431
    Abstract: A semiconductor package that includes a semiconductor die and a heat spreader thermally coupled to the semiconductor and disposed at least partially within the molded housing of the package.
    Type: Application
    Filed: October 18, 2013
    Publication date: March 27, 2014
    Applicant: International Rectifier Corporation
    Inventors: Michael A. Briere, Chuan Cheah, Kunzhong Hu
  • Patent number: 8680627
    Abstract: According to an exemplary embodiment, a stacked half-bridge package includes a control transistor having a control drain for connection to a high voltage input, a control source coupled to a common conductive clip, and a control gate for being driven by a driver IC. The stacked half-bridge package also includes a sync transistor having a sync drain for connection to the common conductive clip, a sync source coupled to a low voltage input, and a sync gate for being driven by the driver IC. The control and sync transistors are stacked on opposite sides of the common conductive clip with the common conductive clip electrically and mechanically coupling the control source with the sync drain, where the common conductive clip has a conductive leg for providing electrical and mechanical connection to an output terminal leadframe.
    Type: Grant
    Filed: October 21, 2011
    Date of Patent: March 25, 2014
    Assignee: International Rectifier Corporation
    Inventors: Eung San Cho, Chuan Cheah, Andrew N. Sawle
  • Patent number: 8674497
    Abstract: According to an exemplary embodiment, a stacked half-bridge package includes a control transistor having a control drain for connection to a high voltage input, a control source coupled to an output terminal, and a control gate for being driven by a driver IC. The stacked half-bridge package also includes a sync transistor having a sync drain for connection to the output terminal, a sync source coupled to a low voltage input, and a sync gate for being driven by the driver IC. A current carrying layer is situated on the sync drain; the control transistor and the sync transistor being stacked on one another, where the current carrying layer provides a high current connection between the sync drain and the control source.
    Type: Grant
    Filed: October 21, 2011
    Date of Patent: March 18, 2014
    Assignee: International Business Machines Corporation
    Inventors: Eung San Cho, Chuan Cheah, Andrew N. Sawle
  • Patent number: 8664754
    Abstract: One exemplary disclosed embodiment comprises a high power semiconductor package configured as a buck converter having a control transistor and a sync transistor disposed on a common leadframe pad, a driver integrated circuit (IC) for driving the control and sync transistors, and conductive clips electrically coupling the top surfaces of the transistors to substrate pads such as leadframe pads. In this manner, the leadframe and the conductive clips provide efficient grounding or current conduction by direct mechanical connection and large surface area conduction, thereby enabling a package with significantly reduced electrical resistance, form factor, complexity, and cost when compared to conventional packaging methods using wirebonds for transistor interconnections.
    Type: Grant
    Filed: April 27, 2011
    Date of Patent: March 4, 2014
    Assignee: International Rectifier Corporation
    Inventors: Eung San Cho, Chuan Cheah
  • Publication number: 20140030854
    Abstract: Some exemplary embodiments of high voltage cascoded III-nitride semiconductor package utilizing clips on a package support surface have been disclosed. One exemplary embodiment comprises a III-nitride transistor attached to a package support surface and having an anode of a diode stacked over a source of the III-nitride transistor, a first conductive clip coupled to a gate of the III-nitride transistor and the anode of the diode, and a second conductive clip coupled to a drain of the III-nitride transistor. The conductive clips are connected to the package support surface and expose respective flat portions that are surface mountable. In this manner, reduced package footprint, improved surge current capability, and higher performance may be achieved compared to conventional wire bonded packages. Furthermore, since a low cost printed circuit board (PCB) may be utilized for the package support surface, expensive leadless fabrication processes may be avoided for cost effective manufacturing.
    Type: Application
    Filed: September 26, 2013
    Publication date: January 30, 2014
    Applicant: International Rectifier Corporation
    Inventors: Chuan Cheah, Dae Keun Park
  • Patent number: 8629566
    Abstract: A multichip module has a substrate, which receives several flip chip and for other semiconductor die on one surface and has vias extending through the substrate from the flip chip bottom electrodes to solder ball electrodes on the bottom of the substrate. Passive components are also mounted on the top of the substrate and are connected to further vias which extend to respective ball contacts at the substrate bottom. In one embodiment, the bottom surfaces and electrodes of the die are insulated and their tops (and drain electrodes) are connected by a moldable conductive layer. In another embodiment the top surface of the substrate is covered by an insulation cap, which may be finned for improved thermal properties. The passives are upended to have their longest dimension perpendicular to the substrate surface and are between the fin valleys.
    Type: Grant
    Filed: September 26, 2005
    Date of Patent: January 14, 2014
    Assignee: International Rectifier Corporation
    Inventors: Bharat Shivkumar, Chuan Cheah
  • Patent number: 8564124
    Abstract: A semiconductor package that includes a semiconductor die and a heat spreader thermally coupled to the semiconductor and disposed at least partially within the molded housing of the package.
    Type: Grant
    Filed: March 7, 2007
    Date of Patent: October 22, 2013
    Assignee: International Rectifier Corporation
    Inventors: Michael A. Briere, Chuan Cheah, Kunzhong Hu
  • Patent number: 8546849
    Abstract: Some exemplary embodiments of high voltage cascoded III-nitride semiconductor package utilizing clips on a package support surface have been disclosed. One exemplary embodiment comprises a III-nitride transistor attached to a package support surface and having an anode of a diode stacked over a source of the III-nitride transistor, a first conductive clip coupled to a gate of the III-nitride transistor and the anode of the diode, and a second conductive clip coupled to a drain of the III-nitride transistor. The conductive clips are connected to the package support surface and expose respective flat portions that are surface mountable. In this manner, reduced package footprint, improved surge current capability, and higher performance may be achieved compared to conventional wire bonded packages. Furthermore, since a low cost printed circuit board (PCB) may be utilized for the package support surface, expensive leadless fabrication processes may be avoided for cost effective manufacturing.
    Type: Grant
    Filed: February 1, 2012
    Date of Patent: October 1, 2013
    Assignee: International Rectifier Corporation
    Inventors: Chuan Cheah, Dae Keun Park
  • Publication number: 20130228794
    Abstract: According to an exemplary embodiment, a stacked half-bridge package includes a control transistor having a control drain for connection to a high voltage input, a control source coupled to an output terminal, and a control gate for being driven by a driver IC. The stacked half-bridge package further includes a sync transistor having a sync drain for connection to the output terminal, a sync source coupled to a low voltage input, and a sync gate for being driven by the driver IC. The control and sync transistors are stacked on opposite sides of a common conductive leadframe with the common conductive leadframe electrically and mechanically coupling the control source with the sync drain. The common conductive leadframe thereby serves as the output terminal.
    Type: Application
    Filed: April 19, 2013
    Publication date: September 5, 2013
    Applicant: International Rectifier Corporation
    Inventors: Eung San Cho, Chuan Cheah, Andrew N. Sawle
  • Patent number: 8497573
    Abstract: In one implementation, a high power semiconductor package is configured as a buck converter including a control transistor, a sync transistor, a driver integrated circuit (IC) for driving the control and sync transistors, and a conductive clip extending from a sync drain on a top surface of the sync transistor to a control source on a top surface of the control transistor. The conductive clip may also connect to substrate pads such as a leadframe pad for current input and output. In this manner, the conductive clip provides an efficient connection between the control source and the sync drain by direct mechanical connection and large surface area conduction, thereby enabling a package with significantly reduced electrical resistance, form factor, complexity, and cost.
    Type: Grant
    Filed: April 27, 2011
    Date of Patent: July 30, 2013
    Assignee: International Rectifier Corporation
    Inventors: Eung San Cho, Chuan Cheah
  • Patent number: 8497574
    Abstract: In one implementation, a high power semiconductor package is configured as a buck converter including a control transistor and a sync transistor disposed on a leadframe, a flip chip driver integrated circuit (IC) for driving the control and sync transistors, and conductive clips electrically coupling the top surfaces of the transistors to substrate pads such as leadframe pads. The source of the control transistor is electrically coupled to the drain of the sync transistor using the leadframe and one of the transistor conductive clips. In this manner, the leadframe and the conductive clips provide efficient current conduction by direct mechanical connection and large surface area conduction, thereby enabling a package with significantly reduced electrical resistance, form factor, complexity, and cost.
    Type: Grant
    Filed: April 27, 2011
    Date of Patent: July 30, 2013
    Assignee: International Rectifier Corporation
    Inventors: Eung San Cho, Chuan Cheah
  • Patent number: 8426952
    Abstract: According to an exemplary embodiment, a stacked half-bridge package includes a control transistor having a control drain for connection to a high voltage input, a control source coupled to an output terminal, and a control gate for being driven by a driver IC. The stacked half-bridge package further includes a sync transistor having a sync drain for connection to the output terminal, a sync source coupled to a low voltage input, and a sync gate for being driven by the driver IC. The control and sync transistors are stacked on opposite sides of a common conductive leadframe with the common conductive leadframe electrically and mechanically coupling the control source with the sync drain. The common conductive leadframe thereby serves as the output terminal.
    Type: Grant
    Filed: October 21, 2011
    Date of Patent: April 23, 2013
    Assignee: International Rectifier Corporation
    Inventors: Eung San Cho, Chuan Cheah, Andrew N. Sawle
  • Patent number: 8399912
    Abstract: Some exemplary embodiments of a III-nitride power device including a HEMT with multiple interconnect metal layers and a solderable front metal structure using solder bars for external circuit connections have been disclosed. The solderable front metal structure may comprise a tri-metal such as TiNiAg, and may be configured to expose source and drain contacts of the HEMT as alternating elongated digits or bars. Additionally, a single package may integrate multiple such HEMTs wherein the front metal structures expose alternating interdigitated source and drain contacts, which may be advantageous for DC-DC power conversion circuit designs using III-nitride devices. By using solder bars for external circuit connections, lateral conduction is enabled, thereby advantageously reducing device Rdson.
    Type: Grant
    Filed: February 1, 2011
    Date of Patent: March 19, 2013
    Assignee: International Rectifier Corporation
    Inventors: Chuan Cheah, Michael A. Briere
  • Publication number: 20120280245
    Abstract: Some exemplary embodiments of high voltage cascoded III-nitride semiconductor package with a stamped leadframe have been disclosed. One exemplary embodiment comprises a III-nitride transistor having an anode of a diode stacked atop a source of the III-nitride transistor, and a stamped leadframe comprising a first bent lead coupled to a gate of the III-nitride transistor and the anode of the diode, and a second bent lead coupled to a drain of the III-nitride transistor. The bent leads expose respective flat portions that are surface mountable. In this manner, reduced package footprint, improved surge current capability, and higher performance may be achieved compared to conventional wire bonded packages. Furthermore, since multiple packages may be assembled at a time, high integration and cost savings may be achieved compared to conventional methods requiring individual package processing and externally sourced parts.
    Type: Application
    Filed: February 1, 2012
    Publication date: November 8, 2012
    Applicant: INTERNATIONAL RECTIFIER CORPORATION
    Inventors: Chuan Cheah, Dae Keun Park
  • Publication number: 20120280246
    Abstract: Some exemplary embodiments of high voltage cascaded III-nitride semiconductor package with an etched leadframe have been disclosed. One exemplary embodiment comprises a III-nitride transistor having an anode of a diode stacked over a source of the III-nitride transistor, and a leadframe that is etched to form a first leadframe paddle portion coupled to a gate of the III-nitride transistor and the anode of the diode, and a second leadframe paddle portion coupled to a drain of the III-nitride transistor. The leadframe paddle portions enable the package to be surface mountable. In this manner, reduced package footprint, improved surge current capability, and higher performance may be achieved compared to conventional wire bonded packages. Furthermore, since multiple packages may be assembled at a time, high integration and cost savings may be achieved compared to conventional methods requiring individual package processing and externally sourced parts.
    Type: Application
    Filed: February 1, 2012
    Publication date: November 8, 2012
    Applicant: INTERNATIONAL RECTIFIER CORPORATION
    Inventors: Chuan Cheah, Dae Keun Park
  • Publication number: 20120280247
    Abstract: Some exemplary embodiments of high voltage cascoded III-nitride semiconductor package utilizing clips on a package support surface have been disclosed. One exemplary embodiment comprises a III-nitride transistor attached to a package support surface and having an anode of a diode stacked over a source of the III-nitride transistor, a first conductive clip coupled to a gate of the III-nitride transistor and the anode of the diode, and a second conductive clip coupled to a drain of the III-nitride transistor. The conductive clips are connected to the package support surface and expose respective flat portions that are surface mountable. In this manner, reduced package footprint, improved surge current capability, and higher performance may be achieved compared to conventional wire bonded packages. Furthermore, since a low cost printed circuit board (PCB) may be utilized for the package support surface, expensive leadless fabrication processes may be avoided for cost effective manufacturing.
    Type: Application
    Filed: February 1, 2012
    Publication date: November 8, 2012
    Applicant: International Rectifier Corporation
    Inventors: Chuan Cheah, Dae Keun Park
  • Patent number: 8253224
    Abstract: A copper strap for a semiconductor device package having a contact electrically connected to a die electrode, a leg portion electrically connected to a lead frame, a web portion positioned between the contact and the leg portion and connected to the leg portion and a connection region connecting the web portion to the contact. The contact includes a body having a plurality of formations, each of the plurality of formations having a concavity and an opposing convexity positioned to generally face the die electrode.
    Type: Grant
    Filed: November 12, 2010
    Date of Patent: August 28, 2012
    Assignee: International Rectifier Corporation
    Inventors: Kunzhong Hu, Chuan Cheah
  • Publication number: 20120181624
    Abstract: According to an exemplary embodiment, a stacked half-bridge package includes a control transistor having a control drain for connection to a high voltage input, a control source coupled to a common conductive clip, and a control gate for being driven by a driver IC. The stacked half-bridge package also includes a sync transistor having a sync drain for connection to the common conductive clip, a sync source coupled to a low voltage input, and a sync gate for being driven by the driver IC. The control and sync transistors are stacked on opposite sides of the common conductive clip with the common conductive clip electrically and mechanically coupling the control source with the sync drain, where the common conductive clip has a conductive leg for providing electrical and mechanical connection to an output terminal leadframe.
    Type: Application
    Filed: October 21, 2011
    Publication date: July 19, 2012
    Applicant: INTERNATIONAL RECTIFIER CORPORATION
    Inventors: Eung San Cho, Chuan Cheah, Andrew N. Sawle
  • Publication number: 20120181674
    Abstract: According to an exemplary embodiment, a stacked half-bridge package includes a control transistor having a control drain for connection to a high voltage input, a control source coupled to an output terminal, and a control gate for being driven by a driver IC. The stacked half-bridge package further includes a sync transistor having a sync drain for connection to the output terminal, a sync source coupled to a low voltage input, and a sync gate for being driven by the driver IC. The control and sync transistors are stacked on opposite sides of a common conductive leadframe with the common conductive leadframe electrically and mechanically coupling the control source with the sync drain. The common conductive leadframe thereby serves as the output terminal.
    Type: Application
    Filed: October 21, 2011
    Publication date: July 19, 2012
    Applicant: INTERNATIONAL RECTIFIER CORPORATION
    Inventors: Eung San Cho, Chuan Cheah, Andrew N. Sawle
  • Publication number: 20120181681
    Abstract: According to an exemplary embodiment, a stacked half-bridge package includes a control transistor having a control drain for connection to a high voltage input, a control source coupled to an output terminal, and a control gate for being driven by a driver IC. The stacked half-bridge package also includes a sync transistor having a sync drain for connection to the output terminal, a sync source coupled to a low voltage input, and a sync gate for being driven by the driver IC. A current carrying layer is situated on the sync drain; the control transistor and the sync transistor being stacked on one another, where the current carrying layer provides a high current connection between the sync drain and the control source.
    Type: Application
    Filed: October 21, 2011
    Publication date: July 19, 2012
    Applicant: INTERNATIONAL RECTIFIER CORPORATION
    Inventors: Eung San Cho, Chuan Cheah, Andrew N. Sawle