Patents Assigned to VLSI Technology, Inc.
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Patent number: 5899707Abstract: An antifuse structure and method for making the antifuse structure having a doped antifuse layer is disclosed. The doped antifuse layer is preferably deposited over a lower electrode. A barrier layer may then be formed over the doped antifuse layer and an upper electrode may subsequently be deposited over the barrier layer. The method of depositing the doped antifuse layer includes: (a) providing a chemical vapor deposition reactor having a support chuck for supporting a partially fabricated silicon wafer; (b) powering up the chemical vapor deposition reactor and heating the partially fabricated silicon wafer; (c) selecting a dopant species for the antifuse layer (e.g, n-type or p-type); (d) introducing a gaseous mixture of a silane compound and the selected dopant species into the chemical vapor deposition reactor with the aid of a neutral species; and (e) depositing the antifuse layer over the lower electrode.Type: GrantFiled: August 20, 1996Date of Patent: May 4, 1999Assignee: VLSI Technology, Inc.Inventors: Ivan Sanchez, Landon B. Vines
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Patent number: 5898711Abstract: Secure operations within an integrated circuit are protected. In order to perform the protection a plurality of single event upset detectors are distributed within the integrated circuit. The single event upset detectors include bit-registers. Each of the plurality of the single event upset detectors is monitored for a single event upset. When a single event upset in any of the single event upset detectors is detected, an error condition is indicated.Type: GrantFiled: May 15, 1997Date of Patent: April 27, 1999Assignee: VLSI Technology, Inc.Inventor: Mark Leonard Buer
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Patent number: 5898479Abstract: A focus evaluation technique for photolithography equipment is disclosed. This technique includes providing a substrate having a photoresist coating for treatment by the equipment. The equipment is activated to focus a first part of a image on a region of the surface and defocus a second part of the image relative to the region. The region is tilted relative to an image plane defined by the equipment. This activation is repeated for each of a number of spaced-apart regions along the surface. The substrate is processed to provide a pattern for each of the regions corresponding to the first and second parts. The equipment is characterized from the pattern for each of the regions. This characterization may result from inspection of the pattern relative to reference marks provided for each region. Focus information for the equipment which accounts for lens heating may be determined from this inspection.Type: GrantFiled: July 10, 1997Date of Patent: April 27, 1999Assignee: VLSI Technology, Inc.Inventors: Walter Bryan Hubbard, Rosanna Kirk
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Patent number: 5896299Abstract: The invention relates to a computer implemented process for fixing hold time violations in hierarchical designs of electronic circuits. The process comprises the steps of:1) synthesizing a RTL-HDL type description of the circuit to form a synthesized design,2) synthesizing a clock tree and adding it to the synthesized design produced in step 1,3) optimizing the synthesized design resulting from step 2, and fixing upper-bounded timing constraints by using a real clock timing (latency and skew) and worst case conditions,4) fixing lower-bounded timing violations in the optimized synthesized design resulting from step 3, using a real clock timing, using best case conditions,5) re-fixing possible upper-bounded timing constraints newly created and possible upper-bounded timing constraints increased in step 4,6) fixing post-layout upper-bounded timing violations.Type: GrantFiled: October 13, 1995Date of Patent: April 20, 1999Assignee: VLSI Technology, Inc.Inventors: Arnold Ginetti, Fran.cedilla.ois Silve, Jean-Michel Fernandez
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Patent number: 5895245Abstract: A method for preparing a semiconductor substrate and a polysilicon gate for subsequent silicide formation. In one embodiment, the present invention performs an oxide etch to remove oxide from source and drain diffusion regions of the semiconductor substrate and from the top surface of the polysilicon gate. Next, the present invention subjects the semiconductor substrate and the polysilicon gate to an ashing environment. In the present invention, the ashing environment is comprised of H.sub.2 O vapor, and a gaseous fluorocarbon or a fluorinated hydrocarbon gas. In so doing, contaminants introduced into the source and drain diffusion regions of the semiconductor substrate and into the top surface of the polysilicon gate during the oxide etch are removed. Next, the present invention performs a semiconductor wafer surface clean step. The semiconductor wafer surface clean step provides a semiconductor wafer surface which is substantially similar to a virgin silicon surface.Type: GrantFiled: June 17, 1997Date of Patent: April 20, 1999Assignee: VLSI Technology, Inc.Inventors: Ian Robert Harvey, Xi-Wei Lin, Ramiro Solis
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Patent number: 5896550Abstract: Versatility of access to a register set within a direct memory access (DMA) controller is increased. The DMA controller controls direct memory access transfers to and from a main memory. When a first control field in a configuration register has a first value, normal operating access is provided to a register set within the DMA controller. The register set provides control and status of the direct memory access transfers to and from the main memory. When the first control field in the configuration register has a second value special access is provided to the register set. The special access allows storage and restoration of a state of a DMA transfer.Type: GrantFiled: April 3, 1997Date of Patent: April 20, 1999Assignee: VLSI Technology, Inc.Inventors: Omer Lem Wehunt, Jeffrey M. Lavin
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Patent number: 5896514Abstract: Within a single integrated circuit, a bus operates in accordance with a bus protocol. The bus protocol includes a first control signal which, when not implemented within a single integrated circuit, is implemented using a pull-up resistor and tri-state gates within functional blocks attached to the bus. A first functional block includes a first input line for receiving an input component of the first control signal, and includes first logic means for generating a first output component of the first control signal. A second functional block includes a second input line for receiving the input component of the first control signal, and includes second logic means for generating a second output component of the first control signal. A logic block includes first logic for generating the input component of the first control signal. The first logic utilizes the first output component and the second output component to generate the input component of the first control signal.Type: GrantFiled: August 23, 1997Date of Patent: April 20, 1999Assignee: VLSI Technology, Inc.Inventor: David Gerard Spaniol
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Patent number: 5895469Abstract: The present invention relates to a system and a method for reducing access times for retrieving audio samples. The system uses a wave table cache. The wave table cache allows devices such as a Digital Signal Processor (DSP) to retrieve audio samples in a linear fashion from the wave table cache at a rate much faster than individually fetching the required portions of the audio sample from the main memory of the system. The DSP may then use the audio samples to generate signals to create sounds based on the audio samples.Type: GrantFiled: March 8, 1996Date of Patent: April 20, 1999Assignee: VLSI Technology, Inc.Inventors: Gregg D. Lahti, Gary D. Hicok, Scott E. Harrow
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Patent number: 5894280Abstract: A digital to analog converter (DAC) offset autocalibration system in a digital synthesizer integrated circuit. The present invention includes a DAC coupled to a filter. The input of the DAC accepts digital values for conversion to an analog signal. The output of the DAC is coupled to the input of the filter. The filter smoothes the analog signal received from the DAC. A switch is coupled to the filter output to receive the analog signal. A comparator is coupled to the switch. The input of the comparator receives the analog signal from the filter output via the switch. An autocalibration control circuit is coupled to the output of the comparator, to the switch, and to the DAC. The autocalibration control circuit is adapted to input a value to the DAC in order to determine an offset correction from the output of the comparator and adjust the analog signal using the offset correction.Type: GrantFiled: February 5, 1997Date of Patent: April 13, 1999Assignee: VLSI Technology, Inc.Inventors: Bernard Ginetti, Philippe Gaglione
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Patent number: 5892155Abstract: A fixture for use with a wire pull tester that tests the strength of a bond between an electrical contact of a semiconductor device and a wire affixed to the electrical contact. The fixture comprises a device support, a mounting surface provided on the device support, and a port provided at the mounting surface. The device support may include a height adjustment mechanism. The mounting surface may be configured to engage a surface of the semiconductor device and includes a port with which an air pressure differential is produced to maintain engagement between the mounting surface and the semiconductor device surface.Type: GrantFiled: August 11, 1997Date of Patent: April 6, 1999Assignee: VLSI Technology, Inc.Inventor: Fredrick James Vanderlip
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Patent number: 5892978Abstract: An apparatus and method for minimizing bus traffic by combining write operations is disclosed. The present invention detects the occurrence of consecutive byte updates to a common 32-bit block. This is accomplished by using comparators to examine the addresses of consecutive write operations. If it is determined that the consecutive write operations are indeed to a common 32-bit block, they are combined. The address of the next write operation is also, similarly checked. All of the writes into that particular block are combined in a write combine register. The contents of this register is then transferred to a write buffer. When bus access is granted, the combined byte updates stored in the write buffer are issued in a single memory write cycle to the bus, thereby minimizing the number of write cycles actually required to transfer the data.Type: GrantFiled: July 24, 1996Date of Patent: April 6, 1999Assignee: VLSI Technology, Inc.Inventors: Gabriel R. Munguia, Ned D. Garinger, Nicholas J. Richardson
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Patent number: 5892694Abstract: A method and implementing system includes transmitting a sampled and digitized source analog signal which is sampled for transmission at a rate of FT, to a receiving device and converting the received signal by a first sample rate converter circuit which is effective to multiply the sample rate FT by a first factor "N". The converted signal is then processed by a receiver sampler circuit and applied to a second sample rate converter circuit operating at a rate of a receiver frequency FR. The second sample rate converter circuit is effective to divide the processed signal by a second factor "M". The signal is then processed by a digital to analog converter and filtered to filter out the spurious components and provide a reproduction of the source analog signal.Type: GrantFiled: May 1, 1997Date of Patent: April 6, 1999Assignee: VLSI Technology, Inc.Inventor: Stefan Ott
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Patent number: 5889389Abstract: The present invention is a micro-electromechanical voltage shifter. According to one embodiment, the voltage shifter of the present invention comprises a capacitor and micro-electromechanical means for changing a capacitance of the capacitor. The capacitor is initially charged and then electrically isolated. When the capacitance is altered, potential difference across the capacitor is shifted accordingly. In one embodiment of the present invention, the micro-electromechanical means includes a gear wheel driven by a micro-motor. The gear wheel preferably includes a plurality of teeth protruding along a circumference of the gear wheel. Further, the gear wheel is positioned next to the capacitor and configured to move the teeth into and out of a gap between the capacitor plates. As the teeth is preferably made of dielectric material, the voltage across the capacitor is changed as a tooth enters or leaves the gap. In another embodiment, the teeth may be made of a conducting material.Type: GrantFiled: January 28, 1998Date of Patent: March 30, 1999Assignee: VLSI Technology, Inc.Inventors: Subhas Bothra, Jayarama N. Shenoy
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Patent number: 5884052Abstract: The present invention comprises a smart retry system for a PCI (peripheral component interconnect) agent in a PCI bus system. The system of the present invention includes an initiator PCI agent and a retry delay register coupled to the initiator PCI agent. The initiator PCI agent is adapted to couple to a PCI bus to communicate with a target PCI agent, via the PCI bus, by initiating a data transaction. The retry delay register is coupled to the PCI agent and the PCI bus. The retry delay register is adapted to receive a delay input via the PCI bus. The delay input describes a latency period of the target PCI agent, wherein the latency period is the amount of the delay. The retry delay register couples the delay input to the initiator PCI agent such that the initiator PCI agent initiates a retry at the expiration of the latency period of the target PCI agent in order to efficiently execute an access to the target PCI agent.Type: GrantFiled: July 14, 1997Date of Patent: March 16, 1999Assignee: VLSI Technology, Inc.Inventors: Peter Chambers, Ken Jaramillo
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Patent number: 5882998Abstract: Disclosed is a semiconductor fuse structure having a low power programming threshold and anti-reverse engineering characteristics. The fuse structure includes a substrate having a field oxide region. A polysilicon strip that has an increased dopant concentration region lies over the field oxide region. The fuse structure further includes a silicided metallization layer having first and second regions lying over the polysilicon strip. The first region has a first thickness, and the second region has a second thickness that is less than the first thickness and is positioned substantially over the increased dopant concentration region of the polysilicon strip. Preferably, the first region of the silicided metallization layer has a first side and a second side located on opposite sides of the second region, and the resulting fuse structure is substantially rectangular in shape. Therefore, the semiconductor fuse structure can be programmed by breaking the second region.Type: GrantFiled: April 3, 1998Date of Patent: March 16, 1999Assignee: VLSI Technology, Inc.Inventors: Harlan Lee Sur, Jr., Subhas Bothra, Xi-Wei Lin, Martin H. Manley, Robert Payne
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Patent number: 5883011Abstract: A method of removing an inorganic antireflective coating from a semiconductor substrate and a method of forming an integrated circuit (IC) are provided. In the former method, a sacrificial layer is formed over a semiconductor substrate, the layer being selectively removable from the substrate and compatible with photolithography. An inorganic antireflective coating such as SiON is then formed over the sacrificial layer. Thereafter, the sacrificial layer is removed from the substrate to lift the coating off the substrate. Preferred materials for the sacrificial layer include TiN, tetraethyl orthosilicate-based silicon oxide, spin-on-glass (SOG) such as hydrogen silsesquioxane and methyl silsesquioxane, and porous polymeric materials. In the latter method, a patterned layer of photoresist material is formed over the anitreflective coating.Type: GrantFiled: June 18, 1997Date of Patent: March 16, 1999Assignee: VLSI Technology, Inc.Inventors: Xi-Wei Lin, Satyendra Sethi, Henry Lee
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Patent number: 5882982Abstract: A shallow trench isolation structure and method for forming such structure. In one embodiment, the semiconductor device isolating structure of the present invention includes a trench formed into a semiconductor substrate. A cross-section of the trench has a first sidewall sloping inwardly towards the center of a substantially planar bottom surface, and a second sidewall sloping inwardly towards the center of the substantially planar bottom surface. Additionally, a cross section of the trench has a first rounded bottom trench corner at an interface of the first sidewall and the substantially planar bottom surface, and a second rounded bottom trench corner at an interface of the second sidewall and the substantially planar bottom surface.Type: GrantFiled: January 16, 1997Date of Patent: March 16, 1999Assignee: VLSI Technology, Inc.Inventors: Jie Zheng, Calvin Todd Gabriel, Suzanne Monsees
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Patent number: 5882997Abstract: A resistive load structure and method for making a resistive load structure for an integrated circuit includes the use of an amorphous silicon "antifuse" material. The resistive load structure can be used in an SRAM cell to provide a load to counteract charge leakage at the drains of two pull-down transistors and two pass transistors of the SRAM cell. The resistive load structure is advantageously formed by depositing an amorphous silicon pad over a conductive via, and the resistance of the resistive load structure is controlled by adjusting the thickness of the amorphous silicon pad and varying the diameter of the underlying conductive via.Type: GrantFiled: October 21, 1997Date of Patent: March 16, 1999Assignee: VLSI Technology, Inc.Inventors: Harlan Lee Sur, Jr., Subhas Bothra
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Patent number: 5880519Abstract: Disclosed is a method for making a passivation coated semiconductor structure. The method includes providing a substrate having a metallization line patterned over the substrate. The metallization line defining at least one interconnect feature having a first thickness, and depositing a first silicon nitride barrier layer having a second thickness over the substrate and the metallization line. The method further including applying an oxide material over the first silicon nitride barrier layer that overlies the substrate and the metallization line. The oxide application includes a deposition component and a sputtering component, and the sputtering component is configured to remove at least a part of an edge of the first silicon nitride layer. The edge is defined by the metallization line underlying the first silicon nitride layer.Type: GrantFiled: May 15, 1997Date of Patent: March 9, 1999Assignee: VLSI Technology, Inc.Inventors: Subhas Bothra, Ling Q. Qian
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Patent number: 5880006Abstract: A method for forming a semiconductor structure on an active area mesa with minimal loss of field oxide deposited in isolation trenches adjacent the mesa. The trench insulating material is protected by an etch barrier layer having at least a partial resistance to etchants used in further device processing steps. The barrier layer may also be deposited over the surface of the substrate to protect it from damage during device processing. The barrier layer may be removed by an etchant having a selectivity for the barrier layer over that of the surrounding device elements. Final processing of the device may be completed once the barrier layer is removed.Type: GrantFiled: May 22, 1998Date of Patent: March 9, 1999Assignee: VLSI Technology, Inc.Inventors: Xi-Wei Lin, Henry Lee, Ian R. Harvey