Patents Assigned to Alpha and Omega Semiconductor, Inc.
  • Patent number: 8587061
    Abstract: A power MOSFET device and manufacturing method thereof, includes the steps of selectively depositing a first conductive material in the middle region at the bottom of a contact trench and contacting with light-doped N-type epitaxial layer to form a Schottky junction and depositing a second conductive material at the side wall and bottom corner of the contact trench and contacting with P-type heavy-doped body region to form an ohmic junction. The first and second conductive materials can respectively optimize the performance of the ohmic contact and the Schottky contact without compromise. Meanwhile, the corner of the contact trench is surrounded by P-type heavy-doped region thereby effectively reducing the leakage currents accumulated at the corner of the contact trench.
    Type: Grant
    Filed: July 26, 2012
    Date of Patent: November 19, 2013
    Assignee: Alpha & Omega Semiconductor, Inc.
    Inventors: Yeeheng Lee, Yongping Ding, John Chen
  • Patent number: 8586414
    Abstract: A semiconductor package and it manufacturing method includes a lead frame having a die pad, and a source lead with substantially a V groove disposed on a top surface. A semiconductor chip disposed on the die pad. A metal plate connected to a top surface electrode of the chip having a bent extension terminated in the V groove in contact with at least one of the V groove sidewalls.
    Type: Grant
    Filed: December 14, 2010
    Date of Patent: November 19, 2013
    Assignee: Alpha & Omega Semiconductor, Inc.
    Inventors: Yan Xun Xue, Yueh-Se Ho, Hamza Yilmaz, Anup Bhalla, Jun Lu, Kal Liu
  • Patent number: 8569169
    Abstract: A bottom source power metal-oxide-semiconductor field-effect transistor (MOSFET) device includes a gate electrode and a source electrode formed on an initial insulation layer on a first surface of a semiconductor chip and a drain electrode formed on a second surface of the semiconductor chip. The source electrode includes a source metal, a source electrode bump formed on the source metal and a source electrode metal layer on top of the source electrode bump. A first insulation layer covers the gate electrode. A through via aligned to the gate electrode is formed from the second surface of the chip to expose a portion of the gate electrode from the second surface.
    Type: Grant
    Filed: October 13, 2011
    Date of Patent: October 29, 2013
    Assignee: Alpha & Omega Semiconductor, Inc.
    Inventors: Yueh-Se Ho, Yan Xun Xue, Ping Huang
  • Patent number: 8563417
    Abstract: The invention generally relates to a packaging method of an ultra-thin chip, more specifically, the invention relates to a method for packaging the ultra-thin chip with solder ball thermo-compression in wafer level packaging process. The method starts with disposing solder balls on metal pads arranged on the front surface of semiconductor chips that are formed at the front surface of a semiconductor wafer. The solder balls are soften by heating the wafer, a compression plate is applied with a pressure on the top ends of the solder balls thus forming a co-planar top surface at the top ends of the solder balls. A molding compound is deposited on the front surface of the wafer with the top ends of the solder balls exposed. The wafer is then ground from its back surface to reduce its thickness to achieve ultra-thin chip.
    Type: Grant
    Filed: November 22, 2011
    Date of Patent: October 22, 2013
    Assignee: Alpha & Omega Semiconductor, Inc.
    Inventors: Jun Lu, Alex Niu, Yueh-Se Ho, Ping Hoang, Jacky Gong, Yan Xun Xue, Xiaolian Zhang, Ming-Chen Lu
  • Patent number: 8563360
    Abstract: A power semiconductor device package includes a conductive assembly including a connecting structure and a semiconductor die having an aperture formed therethrough, the aperture being sized and configured to spacedly receive the connecting structure. In an alternative embodiment, a power semiconductor device package includes a conductive assembly including a connecting structure and a pair of semiconductor die disposed on either side of the connecting structure in spaced relationship thereto.
    Type: Grant
    Filed: June 8, 2009
    Date of Patent: October 22, 2013
    Assignee: Alpha and Omega Semiconductor, Inc.
    Inventors: Jun Lu, François Hébert, Kai Liu, Xiaotian Zhang
  • Patent number: 8564110
    Abstract: A power semiconductor package has an ultra thin chip with front side molding to reduce substrate resistance; a lead frame unit with grooves located on both side leads provides precise positioning for connecting numerous bridge-shaped metal clips to the front side of the side leads. The bridge-shaped metal clips are provided with bridge structure and half or fully etched through holes for relieving superfluous solder during manufacturing process.
    Type: Grant
    Filed: May 24, 2012
    Date of Patent: October 22, 2013
    Assignee: Alpha & Omega Semiconductor, Inc.
    Inventors: Yan Xun Xue, Yueh-Se Ho, Hamza Yilmaz, Jun Lu, Lei Shi, Liang Zhao, Ping Huang
  • Patent number: 8563361
    Abstract: A WLCSP method comprises: depositing a metal bump on bonding pads of chips; forming a first packaging layer at front surface of wafer to cover metal bumps while forming an un-covered ring at the edge of wafer to expose the ends of each scribe line located between two adjacent chips; thinning first packaging layer to expose metal bumps; forming a groove on front surface of first packaging layer along each scribe line by cutting along a straight line extended by two ends of scribe line exposed on front surface of un-covered ring; grinding back surface of wafer to form a recessed space and a support ring at the edge of the wafer; depositing a metal layer at bottom surface of wafer in recessed space; cutting off the edge portion of wafer; and separating individual chips from wafer by cutting through first packaging layer, the wafer and metal layer along groove.
    Type: Grant
    Filed: July 12, 2012
    Date of Patent: October 22, 2013
    Assignee: Alpha & Omega Semiconductor, Inc.
    Inventors: Yan Xun Xue, Hamza Yilmaz, Yueh-Se Ho, Jun Lu, Ping Huang, Lei Shi, Lei Duan, Yuping Gong
  • Patent number: 8558276
    Abstract: A low voltage transient voltage suppressing (TVS) device supported on a semiconductor substrate supporting an epitaxial layer thereon. The TVS device further includes a bottom-source metal oxide semiconductor field effect transistor (BS-MOSFET) comprises a trench gate surrounded by a drain region encompassed in a body region disposed near a top surface of the semiconductor substrate wherein the drain region interfaces with the body region constituting a junction diode and the drain region encompassed in the body region on top of the epitaxial layer constituting a bipolar transistor with a top electrode disposed on the top surface of the semiconductor functioning as a drain/collector terminal and a bottom electrode disposed on a bottom surface of the semiconductor substrate functioning as a source/emitter electrode.
    Type: Grant
    Filed: June 17, 2009
    Date of Patent: October 15, 2013
    Assignee: Alpha and Omega Semiconductor, Inc.
    Inventor: Madhur Bobde
  • Patent number: 8519520
    Abstract: A semiconductor package method for co-packaging high-side (HS) and low-side (LS) semiconductor chips is disclosed. The HS and LS semiconductor chips are attached to two opposite sides of a lead frame, with a bottom drain electrode of the LS chip connected to a top side of the lead frame and a top source electrode of the HS chip connected to a bottom side of the lead frame through a solder ball. The stacking configuration of HS chip, lead frame and LS chip reduces the package size. A bottom metal layer covering the bottom of HS chip exposed outside of the package body provides both electrical connection and thermal conduction.
    Type: Grant
    Filed: November 22, 2011
    Date of Patent: August 27, 2013
    Assignee: Alpha & Omega Semiconductor, Inc.
    Inventors: YuPing Gong, Yan Xun Xue, Liang Zhao
  • Patent number: 8519525
    Abstract: A semiconductor encapsulation comprises a lead frame further comprising a chip carrier and a plurality of pins in adjacent to the chip carrier. A plurality of grooves opened from an upper surface of the chip carrier partially dividing the chip carrier into a plurality of chip mounting areas. A bottom portion of the grooves is removed for completely isolate each chip mounting area, wherein a width of the bottom portion of the grooves removed is smaller than a width of the grooves. In one embodiment, a groove is located between the chip carrier and the pins with a bottom portion of the groove removed for isolate the pins from the chip carrier, wherein a width of the bottom of the grooves removed is smaller than a width of the grooves.
    Type: Grant
    Filed: July 29, 2010
    Date of Patent: August 27, 2013
    Assignee: Alpha & Omega Semiconductor, Inc.
    Inventors: Yan Xun Xue, Anup Bhalla, Jun Lu
  • Patent number: 8502509
    Abstract: A power conversion system and power control method for reducing cross regulation effect uses a voltage feedback adjustment circuit to modulate an error signal fed back from an output voltage so as to predict the energy of an output corresponding to its load states. While the energy delivered to an output terminal with its load remaining the same does not change, the energy delivered to an output terminal with its load changing is adjusted accordingly. The power conversion system thus effectively reduces the cross regulation effect and obtains excellent steady system output and transient response.
    Type: Grant
    Filed: August 7, 2012
    Date of Patent: August 6, 2013
    Assignee: Alpha & Omega Semiconductor, Inc.
    Inventors: Jean-shin Wu, Ke-Horng Chen
  • Patent number: 8497160
    Abstract: A solder-top enhanced semiconductor device is proposed for packaging. The solder-top device includes a device die with a top metal layer patterned into contact zones and contact enhancement zones. At least one contact zone is electrically connected to at least one contact enhancement zone. Atop each contact enhancement zone is a solder layer for an increased composite thickness thus lowered parasitic impedance. Where the top metal material can not form a uniform good electrical bond with the solder material, the device die further includes an intermediary layer sandwiched between and forming a uniform electrical bond with the top metal layer and the solder layer. A method for making the solder-top device includes lithographically patterning the top metal layer into the contact zones and the contact enhancement zones; then forming a solder layer atop each of the contact enhancement zones using a stencil process for an increased composite thickness.
    Type: Grant
    Filed: July 27, 2012
    Date of Patent: July 30, 2013
    Assignee: Alpha & Omega Semiconductor, Inc.
    Inventors: François Hébert, Anup Bhalla, Kai Liu, Ming Sun
  • Patent number: 8486803
    Abstract: A chip-scale packaging method, with bottom and side of a semiconductor chip encapsulated, includes the following steps: attaching backside of a thinned semiconductor wafer to a dicing tape; separating individual chips by cutting from front side of the wafer at scribe line but not cut through the dicing tape; flipping and attaching the wafer onto a top surface of a double-sided tape, then removing the dicing tape; attaching bottom surface of the double-sided tape on a supporting plate; filling the space between adjacent chips and covering the whole wafer backside with a molding material; flipping the whole structure and remove the supporting plate; placing solder balls at corresponding positions on electrodes of each chip and performing backflow treatment; finally separating individual chip packages by cutting through molding material at the space between adjacent chip packages with molding material encapsulating the bottom and side of each individual semiconductor chip.
    Type: Grant
    Filed: October 13, 2011
    Date of Patent: July 16, 2013
    Assignee: Alpha & Omega Semiconductor, Inc.
    Inventors: Ping Huang, Ruisheng Wu, Lei Duan, Yi Chen, Yuping Gong
  • Patent number: 8481368
    Abstract: The invention relates to a semiconductor package of a flip chip and a method for making the semiconductor package. The semiconductor chip comprises a metal-oxide-semiconductor field effect transistor. On a die paddle including a first base, a second base and a third base, half-etching or punching is performed on the top surfaces of the first base and the second base to obtain plurality of grooves that divide the top surface of the first base into a plurality of areas comprising multiple first connecting areas, and divide the top surface of the second base into a plurality of areas comprising at least a second connecting area. The semiconductor chip is connected to the die paddle at the first connecting areas and the second connecting area.
    Type: Grant
    Filed: April 21, 2011
    Date of Patent: July 9, 2013
    Assignee: Alpha & Omega Semiconductor, Inc.
    Inventors: Yan Xun Xue, Yueh-Se Ho, Hamza Yilmaz, Jun Lu
  • Patent number: 8482048
    Abstract: A bypass capacitor is directly integrated on top of a MOSFET chip. The capacitor comprises multi layers of conductive material and dielectric material staking on top of each other with connection vias through dielectric layer for connecting different conductive layers. The method of integrating the bypass capacitor comprises repeating steps of depositing a dielectric layer, forming connection vias through the dielectric layer, depositing a conductive layer and patterning the conductive layer.
    Type: Grant
    Filed: November 16, 2010
    Date of Patent: July 9, 2013
    Assignee: Alpha & Omega Semiconductor, Inc.
    Inventors: Yan Xun Xue, Anup Bhalla, Hamza Yilmaz, Jun Lu
  • Patent number: 8476752
    Abstract: A package structure for DC-DC converter disclosed herein can reduce the number of encapsulated elements as a low-side MOSFET chip can be stacked above the high-side MOSFET chip of a first die pad, through die pads of different thicknesses or interposers with joint parts of different thicknesses; moreover, it further reduces the size of the entire semiconductor package as a number of bond wires are contained in the space between the controller and the low-side MOSFET chip. Moreover, electrical connection between the top source electrode pin and the bottom source electrode pin of the low-side MOSFET chip is realized with a metal joint plate, such that when the DC-DC converter is sealed with plastic, the metal joint plate can be exposed outside to improve the thermal performance and effectively reduce the thickness of the semiconductor package.
    Type: Grant
    Filed: June 12, 2012
    Date of Patent: July 2, 2013
    Assignee: Alpha & Omega Semiconductor, Inc.
    Inventors: Yueh-Se Ho, Yan Xun Xue, Jun Lu
  • Patent number: 8466060
    Abstract: A thin and stackable power MOSFET (SP-MOSFET) and method are proposed. The SVP-MOSFET includes semiconductor substrate with bottom drain metal layer. Formed atop the semiconductor substrate are trenched gate regions and source-body regions. A patterned gate metal layer and source-body metal layer respectively contact trenched gate regions and source-body regions. At least one of through substrate drain via (TSDV), through substrate gate via (TSGV), through substrate source via (TSSV) is provided. The TSDV, formed through semiconductor substrate and in contact with drain metal layer, has top drain contacting pad and bottom drain contacting pad for making top and bottom contacts thereto. Similarly the TSGV, formed through semiconductor substrate and in contact with gate metal layer, has top gate contacting pad and bottom gate contacting pad. Likewise the TSSV, formed through semiconductor substrate and in contact with source-body metal layer, has top source contacting pad and bottom source contacting pad.
    Type: Grant
    Filed: April 30, 2010
    Date of Patent: June 18, 2013
    Assignee: Alpha & Omega Semiconductor, Inc.
    Inventor: Tao Feng
  • Patent number: 8456141
    Abstract: A boost converter for high power and high output voltage applications includes a low voltage controller integrated circuit and a high voltage, vertical, discrete field effect transistor, both of which are packed in a single package on separate electrically isolated die pads.
    Type: Grant
    Filed: September 1, 2011
    Date of Patent: June 4, 2013
    Assignee: Alpha & Omega Semiconductor, Inc.
    Inventors: Allen Chang, Wai-Keung Peter Cheng
  • Patent number: 8450152
    Abstract: A double-side exposed semiconductor device includes an electric conductive first lead frame attached on top of a thermal conductive but electrical nonconductive second lead frame and a semiconductor chip flipped and attached on top of the first lead frame. The gate and source electrodes on top of the flipped chip form electrical connections with gate and source pins of the first lead frame respectively. The flipped chip and center portions of the first and second lead frames are then encapsulated with a molding compound, such that the heat sink formed at the center of the second lead frame and the drain electrode at bottom of the semiconductor chip are exposed on two opposite sides of the semiconductor device. Thus, heat dissipation performance of the semiconductor device is effectively improved without increasing the size of the semiconductor device.
    Type: Grant
    Filed: July 28, 2011
    Date of Patent: May 28, 2013
    Assignee: Alpha & Omega Semiconductor, Inc.
    Inventors: Yuping Gong, Yan Xun Xue
  • Publication number: 20130119393
    Abstract: A vertical conduction nitride-based Schottky diode is formed using an insulating substrate which was lifted off after the diode device is encapsulated on the front side with a wafer level molding compound. The wafer level molding compound provides structural support on the front side of the diode device to allow the insulating substrate to be lifted off so that a conductive layer can be formed on the backside of the diode device as the cathode electrode. A vertical conduction nitride-based Schottky diode is thus realized. In another embodiment, a protection circuit for a vertical GaN Schottky diode employs a silicon-based vertical PN junction diode connected in parallel to the GaN Schottky diode to divert reverse bias avalanche current.
    Type: Application
    Filed: November 11, 2011
    Publication date: May 16, 2013
    Applicant: ALPHA AND OMEGA SEMICONDUCTOR INC.
    Inventors: TingGang Zhu, Anup Bhalla, Ping Huang, Yueh-se Ho