Patents by Inventor Madhur Bobde

Madhur Bobde 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: 11869967
    Abstract: An improved inverted field-effect-transistor semiconductor device and method of making thereof may comprise a source layer on a bottom and a drain disposed on a top of a semiconductor substrate and a vertical current conducting channel between the source layer and the drain controlled by a trench gate electrode disposed in a gate trench lined with an insulating material. A heavily doped drain region is disposed near the top of the substrate surrounding an upper portion of a shield trench and the gate trench. A doped body contact region is disposed in the substrate and surrounding a lower portion of the shield trench. A shield electrode extends upward from the source layer in the shield trench for electrically shorting the source layer and the body region wherein the shield structure extends upward to a heavily doped drain region and is insulated from the heavily doped drain region to act as a shield electrode.
    Type: Grant
    Filed: August 12, 2021
    Date of Patent: January 9, 2024
    Assignee: ALPHA AND OMEGA SEMICONDUCTOR INTERNATIONAL LP
    Inventors: Sik Lui, Madhur Bobde, Lingpeng Guan, Lei Zhang
  • Publication number: 20230420340
    Abstract: A semiconductor package includes a lead frame, a chip, and a molding encapsulation. The lead frame comprises a die paddle, a first plurality of leads, additional one or more leads, a second plurality of leads, a first tie bar, a second tie bar, a third tie bar, and a fourth tie bar. A respective end surface of each lead of the first plurality of leads, the additional one or more leads, and the second plurality of leads is plated with a metal. A respective end surface of the first tie bar, the second tie bar, the third tie bar, and the fourth tie bar is not plated with the metal. A method for fabricating a semiconductor package includes the steps of providing a lead frame array, mounting a chip, forming a molding encapsulation, applying a trimming process, applying a plating process, and applying a singulation process.
    Type: Application
    Filed: June 28, 2022
    Publication date: December 28, 2023
    Applicant: ALPHA AND OMEGA SEMICONDUCTOR INTERNATIONAL LP
    Inventors: Yan Xun Xue, Madhur Bobde, Long-Ching Wang, Xiaoguang Zeng
  • Patent number: 11784141
    Abstract: A semiconductor package comprises a semiconductor substrate, a first metal layer, an adhesive layer, a second metal layer, a rigid supporting layer, and a plurality of contact pads. A thickness of the semiconductor substrate is equal to or less than 50 microns. A thickness of the rigid supporting layer is larger than the thickness of the semiconductor substrate. A thickness of the second metal layer is larger than a thickness of the first metal layer. A method comprises the steps of providing a device wafer; providing a supporting wafer; attaching the supporting wafer to the device wafer via an adhesive layer; and applying a singulaton process so as to form a plurality of semiconductor packages.
    Type: Grant
    Filed: October 5, 2022
    Date of Patent: October 10, 2023
    Assignee: ALPHA AND OMEGA SEMICONDUCTOR INTERNATIONAL LP
    Inventors: Jun Lu, Long-Ching Wang, Madhur Bobde, Bo Chen, Shuhua Zhou
  • Patent number: 11776994
    Abstract: A silicon carbide MOSFET device and method for making thereof are disclosed. The silicon carbide MOSFET device comprises a substrate heavily doped with a first conductivity type and an epitaxial layer lightly doped with the first conductivity type. A body region of a second conductivity type opposite the first is formed in epitaxial layer and an accumulation mode region of the first conductivity type is formed in the body region and an inversion mode region of the second conductivity type formed in the body region. The accumulation mode region is located between the inversion mode region and a junction field effect transistor (JFET) region of the epitaxial layer.
    Type: Grant
    Filed: February 16, 2021
    Date of Patent: October 3, 2023
    Assignee: Alpha and Omega Semiconductor International LP
    Inventors: David Sheridan, Arash Salemi, Madhur Bobde
  • Patent number: 11756993
    Abstract: An apparatus comprising an insulated gate bipolar transistor and a super junction metal-oxide semiconductor field effect transistor wherein the insulated gate bipolar transistor and the super-junction metal-oxide semiconductor field effect transistor are electrically and optionally structurally coupled.
    Type: Grant
    Filed: May 4, 2022
    Date of Patent: September 12, 2023
    Assignee: Alpha and Omega Semiconductor (Cayman) Ltd.
    Inventors: Madhur Bobde, Lingpeng Guan, Karthik Padmanabhan, Bum-Seok Suh
  • Patent number: 11749716
    Abstract: A semiconductor device includes a semiconductor body having a base region incorporating a field stop zone where the base region and the field stop zone are both formed using an epitaxial process. Furthermore, the epitaxial layer field stop zone is formed with an enhanced doping profile to realize improved soft-switching performance for the semiconductor device. In some embodiments, the enhanced doping profile includes multiple doped regions with peak doping levels where a first doped region adjacent to a first side of the field stop zone has a first peak doping level that is not higher than a last peak doping level of a last doped region adjacent to the base region. The epitaxial layer field stop zone of the present invention enables complex field stop zone doping profiles to be used to obtain the desired soft-switching characteristics in the semiconductor device.
    Type: Grant
    Filed: May 4, 2021
    Date of Patent: September 5, 2023
    Assignee: Alpha and Omega Semiconductor (Cayman) Ltd.
    Inventors: Lei Zhang, Karthik Padmanabhan, Lingpeng Guan, Jian Wang, Lingbing Chen, Wim Aarts, Hongyong Xue, Wenjun Li, Madhur Bobde
  • Patent number: 11721665
    Abstract: A wafer level chip scale semiconductor package comprises a device semiconductor layer, a backside metallization layer, a film laminate layer, and a metal layer. The device semiconductor layer comprises a plurality of metal electrodes disposed on a front surface of the device semiconductor. Each side surface of the backside metallization layer is coplanar with a corresponding side surface of the device semiconductor layer. Each side surface of the metal layer is coplanar with a corresponding side surface of the film laminate layer. A surface area of a back surface of the backside metallization layer is smaller than a surface area of a front surface of the metal layer.
    Type: Grant
    Filed: May 20, 2022
    Date of Patent: August 8, 2023
    Assignee: ALPHA AND OMEGA SEMICONDUCTOR INTERNATIONAL LP
    Inventors: Yan Xun Xue, Madhur Bobde, Long-Ching Wang, Bo Chen
  • Publication number: 20230238440
    Abstract: A device and a method of making the device comprising, a semiconductor substrate layer and an epitaxial layer formed on the semiconductor substrate. One or more trenches are formed in the epitaxial layer, each trench having a pair of opposing sidewalls, wherein a distance between the opposing sidewalls is greater near a bottom of the trench than near a top of the trench, wherein the bottom of the trench is closer to the semiconductor substrate layer than the top.
    Type: Application
    Filed: January 21, 2022
    Publication date: July 27, 2023
    Inventors: Madhur Bobde, Sik Lui, Lei Zhang, Xiaobin Wang
  • Patent number: 11699627
    Abstract: A method comprises the steps of providing a wafer; applying a redistribution layer, grinding a back side of the wafer; depositing a metal layer; and applying a singulation process. A semiconductor package comprises a metal-oxide-semiconductor field-effect transistor (MOSFET), a redistribution layer, and a metal layer. The MOSFET comprises a source electrode, a gate electrode, a drain electrode and a plurality of partial drain plugs. The source electrode, the gate electrode, and the drain electrode are positioned at a front side of the MOSFET.
    Type: Grant
    Filed: February 26, 2021
    Date of Patent: July 11, 2023
    Assignee: ALPHA AND OMEGA SEMICONDUCTOR INTERNATIONAL LP
    Inventors: Yan Xun Xue, Long-Ching Wang, Hongyong Xue, Madhur Bobde, Zhiqiang Niu, Jun Lu
  • Patent number: 11594613
    Abstract: A lateral super junction JFET is formed from stacked alternating P type and N type semiconductor layers over a P-epi layer supported on an N+ substrate. An N+ drain column extends down through the super junction structure and the P-epi to connect to the N+ substrate to make the device a bottom drain device. N+ source column and P+ gate column extend through the super junction but stop at the P-epi layer. A gate-drain avalanche clamp diode is formed from the bottom the P+ gate column through the P-epi to the N+ drain substrate.
    Type: Grant
    Filed: June 13, 2021
    Date of Patent: February 28, 2023
    Assignee: Alpha and Omega Semiconductor, Ltd.
    Inventors: Madhur Bobde, Lingpeng Guan, Anup Bhalla, Hamza Yilmaz
  • Publication number: 20230045954
    Abstract: A trench metal-oxide-semiconductor field-effect transistor (MOSFET) device comprises an active cell area including a plurality of superjunction trench power MOSFETs formed in an epitaxial layer. Each MOSFET includes source and body regions and a contact trench formed between first and second gate trenches. A region of the epitaxial layer between the gate trenches extends to the top surface of the epitaxial layer. An insulated gate electrode is formed in each gate trench. At least a portion of the contact trench extends from a top surface of the epitaxial layer to a depth that is shallower than the bottom of the body region.
    Type: Application
    Filed: November 1, 2022
    Publication date: February 16, 2023
    Inventors: Yi Su, Madhur Bobde
  • Publication number: 20230049581
    Abstract: An improved inverted field-effect-transistor semiconductor device and method of making thereof may comprise a source layer on a bottom and a drain disposed on a top of a semiconductor substrate and a vertical current conducting channel between the source layer and the drain controlled by a trench gate electrode disposed in a gate trench lined with an insulating material. A heavily doped drain region is disposed near the top of the substrate surrounding an upper portion of a shield trench and the gate trench. A doped body contact region is disposed in the substrate and surrounding a lower portion of the shield trench. A shield electrode extends upward from the source layer in the shield trench for electrically shorting the source layer and the body region wherein the shield structure extends upward to a heavily doped drain region and is insulated from the heavily doped drain region to act as a shield electrode.
    Type: Application
    Filed: August 12, 2021
    Publication date: February 16, 2023
    Inventors: Sik Lui, Madhur Bobde, Lingpeng Guan, Lei Zhang
  • Publication number: 20230021687
    Abstract: A semiconductor package comprises a semiconductor substrate, a first metal layer, an adhesive layer, a second metal layer, a rigid supporting layer, and a plurality of contact pads. A thickness of the semiconductor substrate is equal to or less than 50 microns. A thickness of the rigid supporting layer is larger than the thickness of the semiconductor substrate. A thickness of the second metal layer is larger than a thickness of the first metal layer. A method comprises the steps of providing a device wafer; providing a supporting wafer; attaching the supporting wafer to the device wafer via an adhesive layer; and applying a singulaton process so as to form a plurality of semiconductor packages.
    Type: Application
    Filed: October 5, 2022
    Publication date: January 26, 2023
    Applicant: ALPHA AND OMEGA SEMICONDUCTOR INTERNATIONAL LP
    Inventors: Jun Lu, Long-Ching Wang, Madhur Bobde, Bo Chen, Shuhua Zhou
  • Patent number: 11538933
    Abstract: A trench metal-oxide-semiconductor field-effect transistor (MOSFET) device comprises an active cell area including a plurality of superjunction trench power MOSFETs, and a Schottky diode area including a plurality of Schottky diodes formed in the drift region having the superjunction structure. Each of the integrated Schottky diodes includes a Schottky contact between a lightly doped semiconductor layer and a metallic layer.
    Type: Grant
    Filed: September 30, 2020
    Date of Patent: December 27, 2022
    Assignee: ALPHA AND OMEGA SEMICONDUCTOR (CAYMAN) LTD.
    Inventors: Yi Su, Madhur Bobde
  • Patent number: 11508819
    Abstract: A method for forming a superjunction power semiconductor device includes forming multiple epitaxial layers of a first conductivity type on a semiconductor substrate and implanting dopants of a second conductivity type into each epitaxial layer to form a first group of implanted regions in a first region and a second group of implanted regions in a second region in each epitaxial layer. The multiple epitaxial layers are annealed to form multiple columns of the second conductivity type having slanted sidewalls across the first to last epitaxial layers. The columns include a first group of columns formed by the implanted regions of the first group and having a first grading and a second group of columns formed by the implanted regions of the second group and having a second grading, where the second grading is less than the first grading.
    Type: Grant
    Filed: May 6, 2021
    Date of Patent: November 22, 2022
    Assignee: Alpha and Omega Semiconductor (Cayman) Ltd.
    Inventors: Madhur Bobde, Karthik Padmanabhan, Lingpeng Guan
  • Patent number: 11495548
    Abstract: A semiconductor package comprises a semiconductor substrate, a first metal layer, an adhesive layer, a second metal layer, a rigid supporting layer, and a plurality of contact pads. A thickness of the semiconductor substrate is equal to or less than 50 microns. A thickness of the rigid supporting layer is larger than the thickness of the semiconductor substrate. A thickness of the second metal layer is larger than a thickness of the first metal layer. A method comprises the steps of providing a device wafer; providing a supporting wafer; attaching the supporting wafer to the device wafer via an adhesive layer; and applying a singulation process so as to form a plurality of semiconductor packages.
    Type: Grant
    Filed: December 30, 2020
    Date of Patent: November 8, 2022
    Assignee: ALPHA AND OMEGA SEMICONDUCTOR INTERNATIONAL LP
    Inventors: Jun Lu, Long-Ching Wang, Madhur Bobde, Bo Chen, Shuhua Zhou
  • Publication number: 20220278009
    Abstract: A method comprises the steps of providing a wafer; applying a redistribution layer, grinding a back side of the wafer; depositing a metal layer; and applying a singulation process. A semiconductor package comprises a metal-oxide-semiconductor field-effect transistor (MOSFET), a redistribution layer, and a metal layer. The MOSFET comprises a source electrode, a gate electrode, a drain electrode and a plurality of partial drain plugs. The source electrode, the gate electrode, and the drain electrode are positioned at a front side of the MOSFET.
    Type: Application
    Filed: February 26, 2021
    Publication date: September 1, 2022
    Applicant: ALPHA AND OMEGA SEMICONDUCTOR INTERNATIONAL LP
    Inventors: Yan Xun Xue, Long-Ching Wang, Hongyong Xue, Madhur Bobde, Zhiqiang Niu, Jun Lu
  • Publication number: 20220278076
    Abstract: A wafer level chip scale semiconductor package comprises a device semiconductor layer, a backside metallization layer, a film laminate layer, and a metal layer. The device semiconductor layer comprises a plurality of metal electrodes disposed on a front surface of the device semiconductor. Each side surface of the backside metallization layer is coplanar with a corresponding side surface of the device semiconductor layer. Each side surface of the metal layer is coplanar with a corresponding side surface of the film laminate layer. A surface area of a back surface of the backside metallization layer is smaller than a surface area of a front surface of the metal layer.
    Type: Application
    Filed: May 20, 2022
    Publication date: September 1, 2022
    Applicant: ALPHA AND OMEGA SEMICONDUCTOR INTERNATIONAL LP
    Inventors: Yan Xun Xue, Madhur Bobde, Long-Ching Wang, Bo Chen
  • Patent number: 11430762
    Abstract: A semi-wafer level packaging method comprises the steps of providing a wafer; grinding a back side of the wafer; forming a metallization layer; removing a peripheral ring; bonding a first tape; applying a dicing process; bonding a second tape; removing the first tape; bonding a supporting structure; bonding a third tape; removing the second tape; and applying a singulation process. A semi-wafer level packaging method comprises the steps of providing a wafer; attaching a carrier wafer to the wafer; grinding a back side of the wafer; forming a metallization layer; applying a dicing process; bonding a supporting structure; removing the carrier wafer; bonding a tape; and applying a singulation process.
    Type: Grant
    Filed: December 30, 2020
    Date of Patent: August 30, 2022
    Assignee: ALPHA AND OMEGA SEMICONDUCTOR INTERNATIONAL LP
    Inventors: Yan Xun Xue, Madhur Bobde, Long-Ching Wang, Bo Chen
  • Publication number: 20220262896
    Abstract: A silicon carbide MOSFET device and method for making thereof are disclosed. The silicon carbide MOSFET device comprises a substrate heavily doped with a first conductivity type and an epitaxial layer lightly doped with the first conductivity type. A body region of a second conductivity type opposite the first is formed in epitaxial layer and an accumulation mode region of the first conductivity type is formed in the body region and an inversion mode region of the second conductivity type formed in the body region. The accumulation mode region is located between the inversion mode region and a junction field effect transistor (JFET) region of the epitaxial layer.
    Type: Application
    Filed: February 16, 2021
    Publication date: August 18, 2022
    Inventors: David Sheridan, Arash Salemi, Madhur Bobde