Patents Assigned to Alpha and Omega Semiconductor, Inc.
  • Patent number: 9006870
    Abstract: A stacked multi-chip packaging structure comprises a lead frame, a first semiconductor chip mounted on the lead frame, a second semiconductor chip flipped-chip mounted on the lead frame, a metal clip mounted on top of the first and second semiconductor chips and a third semiconductor chip stacked on the meal clip; bonding wires electrically connecting electrodes on the third semiconductor chip to the first and second semiconductor chips and the pins of the lead frame; plastic molding encapsulating the lead frame, the chips and the metal clip.
    Type: Grant
    Filed: July 31, 2013
    Date of Patent: April 14, 2015
    Assignee: Alpha & Omega Semiconductor Inc.
    Inventors: Xiaotian Zhang, Hua Pan, Ming-Chen Lu, Jun Lu, Hamza Yilmaz
  • Patent number: 8981539
    Abstract: A power semiconductor device comprises a lead frame unit, a control die, a first MOSFET die and a second MOSFET die, wherein the lead frame unit comprises at least a die paddle for mounting the first and second MOSFET dies, a first pin and a second pin for connecting to top electrodes of the first and second MOSFET dies, a first row of carrier pins and a second row of carrier pins disposed in-line with the first and second pins respectively for the control die to mount thereon.
    Type: Grant
    Filed: June 10, 2013
    Date of Patent: March 17, 2015
    Assignee: Alpha & Omega Semiconductor, Inc.
    Inventors: Yan Xun Xue, Hamza Yilmaz
  • Patent number: 8969950
    Abstract: A MOSFET device and fabrication method are disclosed. The MOSFET has a drain in chip plane with an epitaxial layer overlay atop. The MOSFET further comprises: a Kelvin-contact body and an embedded Kelvin-contact source; a trench gate extending into the epitaxial layer; a lower contact trench extending through the Kelvin-contact source and at least part of the Kelvin-contact body defining respectively a vertical source-contact surface and a vertical body-contact surface; a patterned dielectric layer atop the Kelvin-contact source and the trench gate; a patterned top metal layer. As a result: a planar ledge is formed atop the Kelvin-contact source; the MOSFET device exhibits a lowered body Kelvin contact impedance and, owing to the presence of the planar ledge, a source Kelvin contact impedance that is lower than an otherwise MOSFET device without the planar ledge; and an integral parallel Schottky diode is also formed.
    Type: Grant
    Filed: November 29, 2011
    Date of Patent: March 3, 2015
    Assignee: Alpha & Omega Semiconductor, Inc.
    Inventor: Ji Pan
  • Patent number: 8952509
    Abstract: The present invention discloses a stacked dual MOSFET package structure and a preparation method thereof. The stacked dual MOSFET package structure comprises a lead frame unit having a die paddle, a first lead and a second lead; a first chip flipped and attached on a top surface of a main paddle of the die paddle; a second chip attached on a bottom surface of the main paddle; and a metal clip mounted on the back of the flipped first chip and electrically connecting an electrode at the back of the first chip to the first lead. A top surface of a metal bump arranged on each electrode at the front of the second chip, a bottom surface of the die pin of the die paddle, a bottom surface of a lead pin of the second lead, and a bottom surface of the first lead are located on the same plane.
    Type: Grant
    Filed: September 19, 2013
    Date of Patent: February 10, 2015
    Assignee: Alpha & Omega Semiconductor, Inc.
    Inventors: Hamza Yilmaz, Yueh-Se Ho, Yan Xun Xue, Jun Lu, Xiaotian Zhang, Zhi Qiang Niu, Ming-Chen Lu, Liang Zhao, YuPing Gong, GuoFeng Lian
  • Patent number: 8952669
    Abstract: An average inductor valley current mode voltage control device for a DC/DC converter comprises a sample-hold inductor valley voltage unit receiving at least two inductor valley currents of at least two consecutive cycles produced by the inductor and then converting the at least two inductor valley currents into an average inductor valley voltage; and a reference voltage generation unit connected to the sample-hold inductor valley voltage unit and a transistor switch of the DC/DC converter and receiving a voltage two times of an external voltage corresponding to two times of an average inductor current produced by the inductor, wherein a reference voltage is generated by subtracting the average inductor valley voltage from the voltage two times of the external voltage for control of the switching of the transistor switch of the DC/DC converter while a peak inductor current is stabilized at a designated value.
    Type: Grant
    Filed: November 30, 2012
    Date of Patent: February 10, 2015
    Assignee: Alpha & Omega Semiconductor, Inc.
    Inventor: Yung-I Chang
  • Patent number: 8937356
    Abstract: An electrostatic discharge (ESD) protection circuit includes a triggering diode that includes a junction between a P-grade (PG) region and an N-well. The PG region has a dopant profile equivalent to a P-drain dopant profile of a PMOS transistor having a breakdown voltage represented by V whereby the triggering diode for conducting a current when a voltage greater than the breakdown voltage V is applied. In an exemplary embodiment, the dopant profile of the PG region includes two dopant implant profiles that include a shallow implant profile with a higher dopant concentration and a deep implant profile with a lower dopant concentration.
    Type: Grant
    Filed: April 5, 2011
    Date of Patent: January 20, 2015
    Assignee: Alpha Omega Semiconductor Inc.
    Inventor: Shekar Mallikarjunaswamy
  • Patent number: 8933550
    Abstract: A semiconductor package for power converter application comprises a low-side MOSFET chip and a high-side MOSFET chip stacking one over the other. The semiconductor package may further enclose a capacitor whereas the capacitor may be a discrete component or an integrated component on chip level with the low-side MOSFET. The semiconductor package may further comprise a PIC chip to provide a complete power converter on semiconductor chip assembly package level.
    Type: Grant
    Filed: April 9, 2012
    Date of Patent: January 13, 2015
    Assignee: Alpha & Omega Semiconductor, Inc.
    Inventors: Yan Xun Xue, Anup Bhalla, Jun Lu
  • Patent number: 8933518
    Abstract: A stacked power semiconductor device includes vertical metal oxide semiconductor field-effect transistors and dual lead frames packaged with flip-chip technology. In the method of manufacturing the stacked power semiconductor device, a first semiconductor chip is flip chip mounted on the first lead frame. A mounting clips is connected to the electrode at back side of the first semiconductor chip. A second semiconductor chip is mounted on the second lead frame, which is then flipped and stacked on the mounting clip.
    Type: Grant
    Filed: January 4, 2013
    Date of Patent: January 13, 2015
    Assignee: Alpha & Omega Semiconductor, Inc.
    Inventors: Yan Xun Xue, Yueh-Se Ho, Lei Shi, Jun Lu, Liang Zhao
  • Patent number: 8933545
    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: April 18, 2013
    Date of Patent: January 13, 2015
    Assignee: Alpha & Omega Semiconductor, Inc.
    Inventors: Yuping Gong, Yan Xun Xue
  • Patent number: 8933549
    Abstract: A dual-leadframe multi-chip package comprises a first leadframe with a first die pad, and a second leadframe with a second die pad; a first chip mounted on the first die pad functioning as a high-side MOSFET and second chip mounted on the second die pad functioning as a low-side MOSFET. The package may further comprises a bypass capacity configured as a third chip mounted on the first die pad or integrated with the first chip. The package may further comprise a three-dimensional connecting plate formed as an integrated structure as the second die pad for electrically connecting a top contact area of the first chip to a bottom contact area of the second chip. A top connecting plate connects a top contact area of the second chip and a top contact area of the third chip to an outer pin of the first leadframe.
    Type: Grant
    Filed: December 13, 2013
    Date of Patent: January 13, 2015
    Assignee: Alpha & Omega Semiconductor, Inc.
    Inventors: Kai Liu, Lei Shi, Jun Lu, Anup Bhalla
  • Patent number: 8884600
    Abstract: A variable reference voltage generation unit used in DC/DC converter includes a sample-hold valley inductor current unit electrically connected to a reference voltage generation unit. The sample-hold valley inductor current unit receives the valley inductor current and converts it into the valley voltage. The reference voltage generation unit receives and converts a current signal two times of a designated current into a voltage signal two times of a designated voltage. The voltage signal two times of reference voltage is then subtracted by the valley voltage to produce the new reference voltage to compare with an inductor voltage for controlling the switching of a switching transistor of the DC/DC convertor.
    Type: Grant
    Filed: December 13, 2011
    Date of Patent: November 11, 2014
    Assignee: Alpha & Omega Semiconductor, Inc.
    Inventor: Yung-I Chang
  • Patent number: 8877555
    Abstract: Preparation methods of forming packaged semiconductor device, specifically for flip-chip vertical power device, are disclosed. In these methods, a vertical semiconductor chip is flip-chip attached to a lead frame and then encapsulated with plastic packing materials. Encapsulated chip is then thinned to a predetermined thickness. Contact terminals connecting the chip with external circuit are formed by etching at least a bottom portion of the lead frame connected.
    Type: Grant
    Filed: November 16, 2012
    Date of Patent: November 4, 2014
    Assignee: Alpha & Omega Semiconductor, Inc.
    Inventors: Lei Shi, Yan Xun Xue, Yuping Gong
  • Patent number: 8866267
    Abstract: A semiconductor device with substrate-side exposed device-side electrode (SEDE) is disclosed. The semiconductor device has semiconductor substrate (SCS) with device-side, substrate-side and semiconductor device region (SDR) at device-side. Device-side electrodes (DSE) are formed for device operation. A through substrate trench (TST) is extended through SCS, reaching a DSE turning it into an SEDE. The SEDE can be interconnected via conductive interconnector through TST. A substrate-side electrode (SSE) and a windowed substrate-side passivation (SSPV) atop SSE can be included. The SSPV defines an area of SSE for spreading solder material during device packaging. A device-side passivation (DSPV) beneath thus covering the device-side of SEDE can be included. A DSE can also include an extended support ledge, stacked below an SEDE, for structurally supporting it during post-wafer processing packaging.
    Type: Grant
    Filed: May 28, 2010
    Date of Patent: October 21, 2014
    Assignee: Alpha & Omega Semiconductor, Inc.
    Inventors: Tao Feng, Anup Bhalla
  • Patent number: 8865523
    Abstract: A method of making a semiconductor packaged device comprises mounting onto a lead frame a bottom of a molded semiconductor chip having a first plastic package body covering a top face of a semiconductor chip, encapsulating the lead frame and the semiconductor chip with a second plastic package body with top surfaces of conductive contact bodies electrically connected to electrodes on the top surface of the semiconductor chip exposed and plating conductive pads on a top surface of the assembly structure to provide external electrical connections to the electrodes through the conductive contact bodies.
    Type: Grant
    Filed: March 15, 2013
    Date of Patent: October 21, 2014
    Assignee: Alpha & Omega Semiconductor, Inc.
    Inventors: Yueh-Se Ho, Yan Xun Xue, Jun Lu, Lei Shi, Liang Zhao, Ping Huang
  • Patent number: 8853003
    Abstract: A method for forming a wafer level chip scale (WLCS) package device with a thick bottom metal comprising the step of attaching a lead frame comprising a plurality of thick bottom metals onto a back metal layer of a semiconductor wafer including a plurality of semiconductor chips having a plurality of bonding pads formed on a front surface of each chip, each thick bottom metal is aligned to a central portion of each chip; a plurality of back side cutting grooves are formed along the scribe lines and filled with a package material, the package material are cut through thus forming a plurality of singulated WLCS package devices.
    Type: Grant
    Filed: September 1, 2012
    Date of Patent: October 7, 2014
    Assignee: Alpha & Omega Semiconductor, Inc.
    Inventor: Yan Xun Xue
  • Patent number: 8841167
    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: July 26, 2013
    Date of Patent: September 23, 2014
    Assignee: Alpha & Omega Semiconductor, Inc.
    Inventors: Yuping Gong, Yan Xun Xue, Liang Zhao
  • Patent number: 8796858
    Abstract: A virtually substrate-less composite power semiconductor device (VSLCPSD) and method are disclosed. The VSLCPSD has a power semiconductor device (PSD), a front-face device carrier (FDC) made out of a carrier material and an intervening bonding layer (IBL). Both carrier and IBL material can be conductive or non-conductive. The PSD has back substrate portion, front semiconductor device portion with patterned front-face device metallization pads and a virtually diminishing thickness TPSD. The FDC has patterned back-face carrier metallizations contacting the front-face device metallization pads, patterned front-face carrier metallization pads and numerous parallelly connected through-carrier conductive vias respectively connecting the back-face carrier metallizations to the front-face carrier metallization pads. The FDC thickness TFDC is large enough to provide structural rigidity to the VSLCPSD.
    Type: Grant
    Filed: June 4, 2012
    Date of Patent: August 5, 2014
    Assignee: Alpha & Omega Semiconductor, Inc.
    Inventors: Tao Feng, Yueh-Se Ho
  • Patent number: 8785296
    Abstract: A packaging method with backside wafer dicing includes the steps of forming a support structure at the front surface of the wafer then depositing a metal layer on a center area of the backside of the wafer after grinding the wafer backside to reduce the wafer thickness; detecting from the backside of the wafer sections of scribe lines formed in the front surface in the region between the edge of the metal layer and the edge of the wafer and cutting the wafer and the metal layer from the wafer backside along a straight line formed by extending a scribe line section detected from the wafer backside.
    Type: Grant
    Filed: February 14, 2012
    Date of Patent: July 22, 2014
    Assignee: Alpha & Omega Semiconductor, Inc.
    Inventors: Yan Xun Xue, Ping Huang, Yueh-Se Ho
  • Patent number: 8778735
    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: June 29, 2013
    Date of Patent: July 15, 2014
    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: 8748268
    Abstract: Method for fabricating MOSFET integrated with Schottky diode (MOSFET/SKY) is disclosed. Gate trench is formed in an epitaxial layer overlaying semiconductor substrate, gate material is deposited therein. Body, source, dielectric regions are successively formed upon epitaxial layer and the gate trench. Top contact trench (TCT) is etched with vertical side walls defining Schottky diode cross-sectional width SDCW through dielectric and source region defining source-contact depth (SCD); and partially into body region by total body-contact depth (TBCD). A heavily-doped embedded body implant region (EBIR) of body-contact depth (BCD)<TBCD is created into side walls of TCT and beneath SCD. An embedded Shannon implant region (ESIR) is created into sub-contact trench zone (SCTZ) beneath TCT floor. A metal layer is formed in contact with ESIR, body and source region. The metal layer also fills TCT and covers dielectric region thus completing the MOSFET/SKY with only one-time etching of its TCT.
    Type: Grant
    Filed: December 20, 2012
    Date of Patent: June 10, 2014
    Assignee: Alpha to Omega Semiconductor, Inc.
    Inventors: Ji Pan, Daniel Ng, Sung-Shan Tai, Anup Bhalla