Patents by Inventor Joe Ko
Joe Ko 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).
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Patent number: 5817577Abstract: A method for eliminating the antenna effect in the manufacture of an integrated circuit in a silicon substrate, wherein there are contact pad areas at the periphery of the integrated circuit and interconnection lines connecting the contact pad areas with the integrated circuit. This is achieved by grounding the contact pad areas to the silicon substrate; processing in a plasma environment that would normally produce electrical charge build-up at the gate oxide of the integrated circuit, but wherein the grounded contact pad areas eliminates the charge build-up; and disabling the grounding of the contact pad areas to retrieve the functioning of the integrated circuit.Type: GrantFiled: November 5, 1996Date of Patent: October 6, 1998Assignee: United Microelectronics Corp.Inventor: Joe Ko
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Patent number: 5716874Abstract: A method of fabricating an EPROM memory increases a coupling ratio and reduces lateral diffusion by forming a gate oxide layer and a coupling insulator individually. A substrate is provided with a field oxide layer to isolate a predetermined active area. A gate oxide layer is formed on the substrate. On the field oxide layer and the gate oxide layer, a polysilicon layer is deposited and defined, whereby a portion of this polysilicon layer and gate oxide layer form a gate electrode. Using the gate electrode as a mask, the substrate is implanted with impurities to provide source and drain electrodes. A dielectric layer is formed on polysilicon layer. A contact window (via) is formed in a predetermined area of dielectric layer. An insulator is deposited and defined by etching, on dielectric layer and the contact window. On the insulator and dielectric layer, a metal contact layer is deposited and defined to cover the insulator.Type: GrantFiled: February 20, 1996Date of Patent: February 10, 1998Assignee: United Microelectronics CorporationInventors: Joe Ko, Gary Hong, Chih-Hung Lin
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Patent number: 5686321Abstract: The invention relates to an improved MOSFET device structure for use in ultra large scale integration and the method of forming the device structure. A local punchthrough stop region is formed directly under the gate electrode using ion implantation. The local punchthrough stop region reduces the expansion of the depletion region in the channel and thereby increases the punchthrough voltage. The local punchthrough stop region is self-aligned with the gate electrode and source/drain region so that critical spacings are maintained even for sub micron devices. The source and drain junction capacitances are also reduced. The invention can be used in either N channel or P channel MOSFET devices. The invention can be used with a conventional source/drain structure as well as a double doped drain structure and a light doped drain structure.Type: GrantFiled: May 6, 1996Date of Patent: November 11, 1997Assignee: United Microelectronics Corp.Inventors: Joe Ko, Chih-Hung Lin
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Patent number: 5654569Abstract: A method of forming a retarded double diffused drain structure, and the resultant retarded double diffused drain structure, for a field effect transistor are described. A silicon substrate with field isolation regions and a gate structure is provided. A layer of photoresist is formed on the field isolation region, the silicon substrate, and the gate structure. The photoresist is patterned to expose the silicon substrate and the gate structure, but covers an area of the silicon substrate that is offset from the field isolation regions. A first ion implant is performed in a vertical direction in exposed regions of the silicon substrate, with suitable dopant having a high doping concentration. The photoresist is removed. A second ion implant is performed in a vertical direction in the silicon substrate, with suitable dopant with higher doping concentration than the first ion implant, in regions between the field isolation regions and the gate structure. The substrate is heated to drive in both the dopants.Type: GrantFiled: August 30, 1996Date of Patent: August 5, 1997Assignee: United Microelectronics CorporationInventor: Joe Ko
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Patent number: 5646062Abstract: An improved semiconductor structure forms a series of FETs that are each connected between an input pad and ground for protecting the semiconductor device from an electrostatic discharge that may appear at the pad. Diffusions form alternate drain and source regions and are spaced apart at the surface of the device. Gate electrodes are located over the substrate between the diffusions so that the drain diffusion on one side of a gate also forms the drain for the FET on the one side and the source diffusion on the other side also forms the source diffusion for an FET on the other side. The electrical connection between the pad and the drain diffusions is formed by connections through the overlying insulation to a midpoint in the drain diffusion. Electrical connections between the gate and ground are formed by extending the conductive pattern that forms the gate. An electrical connection is made between the source diffusion and the gate electrode by a buried contact technique.Type: GrantFiled: January 19, 1995Date of Patent: July 8, 1997Assignee: United Microelectronics CorporationInventors: Lee Chung Yuan, Joe Ko
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Patent number: 5602049Abstract: An improved SRAM cell having ultra-high density and methods for fabrication are described. Each SRAM cell, according to the present invention, has its own buried structure, including word lines (i.e., gate regions) and bit lines (i.e., source/drain regions), thus increasing the cell ratio of channel width of cell transistor to that of pass transistor to keep the data stored in the cell transistor more stable without increasing the area per cell. In addition, according to the present invention, the field isolation between active regions is not field oxide but blankly ion-implanted silicon substrate. Therefore, SRAM cells can be densely integrated due to the absence of bird's beak encroachment. Since the present invention has more planar topography, it is easily adapted to the VLSI process, which is always restricted by the limit of resolution of photolithography, thus increasing the degree of integration.Type: GrantFiled: October 4, 1994Date of Patent: February 11, 1997Assignee: United Microelectronics CorporationInventors: Jemmy Wen, Joe Ko
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Patent number: 5576557Abstract: An electrostatic discharge (ESD) circuit for protecting a semiconductor integrated circuit (IC) device is disclosed. One ESD circuit is located between each I/O buffering pad that connects to one lead pin and the internal circuitry of IC. The ESD circuit is connected to both power terminals. The ESD circuit comprises first and second low-voltage-trigger SCRs (LVTSCRs), each having an anode, a cathode, an anode gate and a cathode gate. The anode and anode gate of the first SCR are connected to a first power terminal, the cathode of the first SCR is connected to its I/O buffering pad, and the cathode gate of the first SCR is connected to the second power terminal. The ESD circuit further comprises a PMOS transistor having drain, source, gate, and bulk terminals. The PMOS transistor's gate, source and bulk terminals are connected to the first power terminal, the PMOS transistor drain terminal is connected to the cathode gate of the first SCR.Type: GrantFiled: April 14, 1995Date of Patent: November 19, 1996Assignee: United Microelectronics Corp.Inventors: Ming-Dou Ker, Chung-Yu Wu, Hun-Hsien Chang, Chung-Yuan Lee, Joe Ko
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Patent number: 5574302Abstract: This invention describes a diving channel device structure and a method of forming the diving channel device structure using deep vertical trenches formed in a silicon substrate crossing shallow vertical trenches formed in the same silicon substrate. The deep vertical trenches are filled with a first heavily doped polysilicon to form the sources and drains of field effect transistors. The shallow vertical trenches are filled with a second highly doped polysilicon to form the gates of the transistors. The device structure provides reduced drain and source resistance which remains nearly constant when the device is scaled to smaller dimensions. The device structure also provides reduced leakage currents and a plane topography. The device structure forms a large effective channel width when the device is scaled to smaller dimensions.Type: GrantFiled: August 24, 1995Date of Patent: November 12, 1996Assignee: United Microelectronics CorporationInventors: Jemmy Wen, Water Lur, Joe Ko
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Patent number: 5565700Abstract: A new surface counter-doped lightly doped source and drain integrated circuit field effect transistor device is described. A gate silicon oxide layer is formed on the silicon substrate. A layer of polysilicon is deposited over the gate silicon oxide layer and etched to form a gate electrode structure. A first ion implantation is performed at a tilt angle to form lightly doped drain regions in the semiconductor substrate wherein the lightly doped drain regions are partially overlapped by the gate electrode structure. A second ion implantation is performed at a larger tilt angle and lower energy than the first ion implantation wherein the second ion implantation counter-dopes the surface of the lightly doped drain regions to form a very lightly doped drain layer thus making the lightly doped drain regions buried regions.Type: GrantFiled: April 20, 1995Date of Patent: October 15, 1996Assignee: United Microelectronics CorporationInventors: Jih W. Chou, Joe Ko, Chun Y. Chang
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Patent number: 5565369Abstract: A method of forming a retarded double diffused drain structure, and the resultant retarded double diffused drain structure, for a field effect transistor are described. A silicon substrate with field isolation regions and a gate structure is provided. A layer of photoresist is formed on the field isolation region, the silicon substrate, and the gate structure. The photoresist is patterned to expose the silicon substrate and the gate structure, but covers an area of the silicon substrate that is offset from the field isolation regions. A first ion implant is performed in a vertical direction in exposed regions of the silicon substrate, with suitable dopant having a high doping concentration. The photoresist is removed. A second ion implant is performed in a vertical direction in the silicon substrate, with suitable dopant with higher doping concentration than the first ion implant, in regions between the field isolation regions and the gate structure. The substrate is heated to drive in both the dopants.Type: GrantFiled: August 7, 1995Date of Patent: October 15, 1996Assignee: United Microelectronics CorporationInventor: Joe Ko
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Patent number: 5559352Abstract: A method of forming an ESD protection device with reduced breakdown voltage, simultaneously with an integrated circuit which includes FET devices, and the resultant device structure, are described. A silicon substrate is provided on which there are field oxide regions, gates, and active regions. A first ion implant of a conductivity-imparting dopant is performed in a vertical direction into the active regions of the ESD protection device and the FET devices. A first insulating layer is formed over the ESD protection device and the FET devices, and over the field oxide regions. The first insulating layer is patterned to create spacers adjacent to the gates of both the ESD protection device and the FET devices. A second ion implant of a conductivity-imparting dopant with higher concentration than dopant from the first ion implant is performed into active regions of both the ESD protection device and the FET devices.Type: GrantFiled: December 12, 1994Date of Patent: September 24, 1996Assignee: United Microelectronics CorporationInventors: Chen-Chiu Hsue, Joe Ko
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Patent number: 5518941Abstract: This invention provides a method of forming a field implant channel stop region and a device using a field implant channel stop region to improve isolation between devices in integrated circuits using field effect transistors. The field implant channel stop region is formed without the use of an extra mask or extra masking steps by means of either a large angle tilted ion implant beam or a higher energy normally directed ion implant beam. The field implant channel stop region is formed with the mask used to form the light doped drain region in place. The field implant channel stop region forms a local increase in the doping level in the device well thereby forming the channel stop region.Type: GrantFiled: September 26, 1994Date of Patent: May 21, 1996Assignee: United Microelectronics CorporationInventors: Chih-Hung Lin, Joe Ko
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Patent number: 5514623Abstract: A multi-level conductive interconnection for an integrated circuit is formed in a silicon substrate, wherein there are large contact pad areas at the periphery of the interconnection. A patterned layer of a polysilicon layer is formed on the substrate to act as a first contact to the integrated circuit. An insulating layer is formed over the polysilicon layer, and openings to the polysilicon layer are formed through the insulating layer. A first layer of metal is formed on the insulator such that the metal electrically connects to the polysilicon through the openings, and also forms large contact pad areas. The first metal is patterned to form an electrical break between the large contact pad areas and the integrated circuit. This break prevents electrical damage to the integrated circuit due to charge build-up during subsequent processing in a plasma environment. A second insulating layer is formed and patterned to provide openings for vias to the first metal layer.Type: GrantFiled: February 13, 1995Date of Patent: May 7, 1996Assignee: United Microelectronics CorporationInventors: Joe Ko, Bill Hsu
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Patent number: 5484743Abstract: The invention relates to a method of forming an improved MOSFET device structure for use in ultra large scale integration devices. A local self-aligned anti-punchthrough region is formed directly under the gate electrode using ion implantation. The local anti-punchthrough region reduces the expansion of the depletion region in the channel and thereby increases the punchthrough voltage. The local anti-punchthrough region is self-aligned with the gate electrode and source/drain region so that critical spacings are maintained even for sub micron devices. Channel mobility is not degraded and the source and drain junction capacitances are reduced. The invention can be used in either N channel or P channel MOSFET devices, and in either LDD (light doped drain) or non-LDD devices.Type: GrantFiled: February 27, 1995Date of Patent: January 16, 1996Assignee: United Microelectronics CorporationInventors: Joe Ko, Chen-Chiu Hsue
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Patent number: 5473169Abstract: A complementary-SCR electrostatic discharge protection circuit in a silicon substrate, coupling to I/O pads for bypassing electrostatic current of positive or negative polarity respect to power supply voltages V.sub.DD and V.sub.SS. The circuit comprises a first SCR and a second SCR each having an anode, a cathode, an anode gate and a cathode gate. The circuit of the present invention preferably includes a finger type layout structure for providing a larger capacity to bypass electrostatic current. It is also characterized by a base-emitter shorting design to avoid a V.sub.DD -to-V.sub.SS latch-up effect.Type: GrantFiled: March 17, 1995Date of Patent: December 5, 1995Assignee: United Microelectronics Corp.Inventors: Ming-Dou Ker, Chung-Yu Wu, Chung-Yuan Lee, Joe Ko
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Patent number: 5460987Abstract: This invention describes a diving channel device structure and a method of forming the diving channel device structure using deep vertical trenches formed in a silicon substrate crossing shallow vertical trenches formed in the same silicon substrate. The deep vertical trenches are filled with a first heavily doped polysilicon to form the sources and drains of field effect transistors. The shallow vertical trenches are filled with a second highly doped polysilicon to form the gates of the transistors. The device structure provides reduced drain and source resistance which remains nearly constant when the device is scaled to smaller dimensions. The device structure also provides reduced leakage currents and a plane topography. The device structure forms a large effective channel width when the device is scaled to smaller dimensions.Type: GrantFiled: December 27, 1994Date of Patent: October 24, 1995Assignee: United Microelectronics CorporationInventors: Jemmy Wen, Water Lur, Joe Ko
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Patent number: 5434108Abstract: A method of subjecting an integrated circuit, having electrically grounded elements and large first metal regions on its surface which are connected to device structures, to a plasma process, is described. Large first metal regions are connected to the electrically grounded elements. The integrated circuit is placed in a chamber for accomplishing the plasma process. The integrated circuit is subjected to the plasma process such that the connecting of the large first metal regions to the electrically grounded elements prevents damage to the device structures. The integrated circuit is removed from the chamber. Finally, the large first metal regions are disconnected from the electrically grounded elements.Type: GrantFiled: September 22, 1993Date of Patent: July 18, 1995Assignee: United Microelectronics CorporationInventors: Joe Ko, Chen-Chiu Hsue
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Patent number: 5393701Abstract: A multi-level conductive interconnection for an integrated circuit is formed in a silicon substrate, wherein there are large contact pad areas at the periphery of the interconnection. A patterned layer of a conductive polysilicon is formed on the substrate to act as a first conductive contact to the integrated circuit. An insulating layer is formed over the polysilicon layer, and openings to the polysilicon layer are formed through the insulating layer. A first layer of metal is formed on the insulator such that the metal electrically connects to the polysilicon through the openings, and also forming large contact pad areas. The first metal is patterned to form an electrical break between the large contact pad areas and the integrated circuit. This break prevents electrical damage to the integrated circuit due to charge build-up during subsequent processing in a plasma environment. A second insulating layer is formed and patterned to provide openings for vias to the first metal layer.Type: GrantFiled: April 8, 1993Date of Patent: February 28, 1995Assignee: United Microelectronics CorporationInventors: Joe Ko, Bill Hsu
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Patent number: 5393693Abstract: A method of forming field oxide isolation regions for submicron technology using oxygen implantation is described. A first insulating layer is formed over a silicon substrate. A second insulating layer is formed over the first insulating layer. A first opening is formed in the first and second insulating layers. Sidewall spacers are formed on the vertical surfaces of the first and second insulating layers, within the first opening, to define a second, smaller opening. A portion of the silicon substrate is removed in the region defined by the second, smaller opening, to form an etched region of the silicon substrate. The sidewall spacers are removed. Oxygen is implanted into the etched region of the silicon substrate and into the region of the silicon substrate under the former location of the sidewall spacers. A portion of the polycrystalline silicon in and above the etched region of the silicon substrate. The field oxide isolation region is formed by heating.Type: GrantFiled: June 6, 1994Date of Patent: February 28, 1995Assignee: United MicroElectronics CorporationInventors: Joe Ko, Chih-Hung Lin
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Patent number: 5374565Abstract: A method of forming an ESD protection device with reduced junction breakdown voltage, simultaneously with an integrated circuit which includes FET devices, and the resultant device structure, are described. A silicon substrate is provided on which there are field oxide regions, gates, and active regions. A first ion implant of a conductivity-imparting dopant is performed in a vertical direction into the active regions of the ESD protection device and the FET devices. A first insulating layer is formed over the ESD protection device and the FET devices, and over the field oxide regions. The first insulating layer is patterned to create spacers adjacent to the gates of both the ESD protection device and the FET devices. A second ion implant of a conductivity-imparting dopant with higher concentration than dopant from the first ion implant is performed into active regions of both the ESD protection device and the FET devices.Type: GrantFiled: October 22, 1993Date of Patent: December 20, 1994Assignee: United Microelectronics CorporationInventors: Chen-Chiu Hsue, Joe Ko