Patents Represented by Attorney Edel M. Young
  • Patent number: 6432808
    Abstract: A method of forming a bond pad area for an integrated circuit provides FSG in the dielectric layer while at the same time minimizes bond pad lift off. The method includes forming a first dielectric layer of fluorinated silicon glass (FSG) on a substrate, then forming an FSG barrier layer on the first dielectric layer. A second, non-FSG dielectric layer is formed on the FSG barrier layer. A barrier metal layer is then formed on the second dielectric layer. Finally, a metal layer is formed on the barrier metal layer. This metal layer provides the surface for adhesion to the bonding wire. The FSG barrier layer absorbs the atoms of fluorine diffused from the first dielectric layer. In this manner, fluorine is prevented from penetrating the second dielectric layer, thereby minimizing bond pad lift off between the second dielectric layer and the barrier metal layer. In one embodiment, the FSG barrier layer includes titanium and/or aluminum.
    Type: Grant
    Filed: December 3, 1999
    Date of Patent: August 13, 2002
    Assignee: Xilinx, Inc.
    Inventors: Michael J. Hart, James Karp
  • Patent number: 6430736
    Abstract: A system and method for evolving configuration bitstreams for a programmable logic device are disclosed. A plurality of data structures having respective sets of data are established. From the sets of data, respective configuration bitstreams are generated, wherein the sets of data are mapped to positions in the bitstreams. The configuration bitstreams are then evaluated for relative suitability to meet predetermined criteria when deployed on a progammable logic device. From the relative suitability of the configuration bitstreams, next-generation data for the data structures are generated using a genetic algorithm applied to sets of data. In the various embodiments, the configuration bitstreams eliminate resource contentions, selectively eliminate asynchronous behavior, include built-in test circuits, and are relocatable. Multiple populations of configuration bitstreams can evolve in parallel over a network.
    Type: Grant
    Filed: June 17, 1999
    Date of Patent: August 6, 2002
    Assignee: Xilinx, Inc.
    Inventors: Delon Levi, Steven A. Guccione
  • Patent number: 6429698
    Abstract: A clock routing circuit is coupled to receive a primary clock signal, a secondary clock signal, and a select signal, all of which may be asynchronous with respect to one another. When the select signal is in a first state, the clock routing circuit passes the primary clock signal as an output clock signal. When the select signal transitions to a second state, the clock routing circuit waits for the primary clock signal to transition in a predetermined direction (i.e., rising edge or falling edge). Upon detecting the transition of the primary clock signal, the clock routing circuit holds the state of the output clock signal. The clock routing circuit then waits for the secondary clock signal to transition in the predetermined direction. Upon detecting the transition of the secondary clock signal, the clock routing circuit passes the secondary clock signal as the output clock signal.
    Type: Grant
    Filed: May 2, 2000
    Date of Patent: August 6, 2002
    Assignee: Xilinx, Inc.
    Inventor: Steven P. Young
  • Patent number: 6427156
    Abstract: An improved CLB architecture, wherein the use of dedicated AND gates to generate a carry chain input signal facilitates low latency multiplication and makes efficient use of four-input function generators. In one embodiment of the invention, when multiplication using a binary addition tree algorithm is used, AND gates to implement single-bit multiplication are provided within the available function generators and duplicated in a dedicated AND gate accessible outside the corresponding function generator as a carry-chain input signal. In another embodiment, carry chain multiplexers can be selectively configured as AND or OR gates to facilitate certain arithmetic or comparison functions for the outputs of a plurality of function generators.
    Type: Grant
    Filed: January 21, 1997
    Date of Patent: July 30, 2002
    Assignee: Xilinx, Inc.
    Inventors: Kenneth D. Chapman, Steven P. Young
  • Patent number: 6426534
    Abstract: Described are mask-alignment detection structures that measure both the direction and extent of misalignment between layers of an integrated circuit. Each structure includes one or more MOS transistors, each of which exhibits a threshold voltage that varies with misalignment in one dimension. The test structures are configured in mirrored pairs, so that misalignment in one direction oppositely affects the threshold voltages of the paired structures. The threshold voltages of the paired structures can therefore be compared to determine the extent and direction of misalignment. Measurements in accordance with the invention are relatively insensitive to process variations, and the structures using to take these measurements can be formed along with other features on an integrated circuit using standard processes. One embodiment of the invention may be used to measure misalignment between active implants and the windows in which active regions are formed.
    Type: Grant
    Filed: May 1, 2000
    Date of Patent: July 30, 2002
    Assignee: Xilinx, Inc.
    Inventors: Kevin T. Look, Shih-Cheng Hsueh
  • Patent number: 6425077
    Abstract: A system and method for reading back data from a programmable logic device (PLD). A clock offset table having one or more clock offset values is constructed. Each clock offset value indicates a relative clock cycle at which a selected bit read from the device is saved and sent to a host computer. The data is read from the PLD at a rate of one bit per readback clock cycle, and the readback clock cycles are counted as the bits are read from the device. When the count of readback clock cycles equals an offset, the bit is selected and saved.
    Type: Grant
    Filed: May 14, 1999
    Date of Patent: July 23, 2002
    Assignee: Xilinx, Inc.
    Inventors: Thach-Kinh Le, Chakravarthy K. Allamsetty, Carl H. Carmichael, Arun K. Mandhania, Donald H. St. Pierre, Jr., Conrad A. Theron
  • Patent number: 6420885
    Abstract: A handler interface apparatus for low-temperature semiconductor device testing that includes a bracket and a handler board. The bracket including an outer frame, an inner frame connected to the outer frame by one or more arms, and a cover plate positioned over a central opening of the inner frame. When the handler board is mounted onto the bracket, conductors extending through the handler board from a device contactor pad are enclosed in a chamber formed by the handler board, the inner frame and the cover plate. The handler board is then mated to the test pins of a device tester, which extend through openings located between the inner frame, the outer frame, and the arms of the bracket. During low temperature testing, dry gas is pumped into the chamber through conduits formed in the arms of the bracket to prevent the condensation of moisture on the conductors located in the chamber. In a second disclosed embodiment, a cover plate is attached directly to a handler board.
    Type: Grant
    Filed: February 10, 2000
    Date of Patent: July 16, 2002
    Assignee: Xilinx, Inc.
    Inventor: Toby Alan Fredrickson
  • Patent number: 6393714
    Abstract: Described are mask-alignment detection structures that measure both the direction and extent of misalignment between layers of an integrated circuit using resistive elements for which resistance varies with misalignment in one dimension. Measurements in accordance with the invention are relatively insensitive to process variations, and the structures using to take these measurements can be formed along with other features on an integrated circuit using standard processes. One embodiment of the invention may be used to measure misalignment between two conductive layers. Other embodiments measure misalignment between diffusion regions and conductors and between diffusion regions and windows through which other diffusion regions are to be formed. A circuit in accordance with one embodiment includes row and column decoders for independently selecting mask-alignment detection structures to reduce the number of test terminals required to implement the detection structures.
    Type: Grant
    Filed: February 25, 2000
    Date of Patent: May 28, 2002
    Assignee: Xilinx, Inc.
    Inventors: Kevin T. Look, Shih-Cheng Hsueh
  • Patent number: 6393591
    Abstract: The Internet is used to test an integrated circuit chip that is provided with boundary scan circuitry and plugged into a circuit board at a customer's location. A host computer at the manufacturer's location runs a web page server having the ability to remotely test a customer's chip. The process is initiated by the customer connecting the circuit board to his own computer and logging onto the web site. The customer transmits customer identification and other data to the web server, which then transmits a downloader program and a JAVA program script to the customer's computer. The customer's computer then uses the downloader program to transmit high and low level device data describing the functionality of the chip to the host computer, which then generates and transmits a set of suitable test vectors to the customer's computer.
    Type: Grant
    Filed: February 12, 1999
    Date of Patent: May 21, 2002
    Assignee: Xilinx, Inc.
    Inventors: Jesse H. Jenkins, IV, Walter H. Edmondson
  • Patent number: 6384627
    Abstract: A method of configuring an FPGA lookup table to implement both exact and relative matching comparators is disclosed. Examples of exact matching of two variables, exact matching of a variable to a constant, relative matching (greater than) of a variable to a constant, and combined exact and relative matching are discussed. Use of the comparator to trigger a logic analyzer to collect data is discussed.
    Type: Grant
    Filed: February 16, 2001
    Date of Patent: May 7, 2002
    Assignee: Xilinx, Inc.
    Inventors: Bradley K. Fross, Edward S. McGettigan
  • Patent number: 6378122
    Abstract: A system and method for evolving configuration bitstreams for a programmable logic device are disclosed. A plurality of data structures having respective sets of data are established. From the sets of data, respective configuration bitstreams are generated, wherein the sets of data are mapped to positions in the bitstreams. The configuration bitstreams are then evaluated for relative suitability to meet predetermined criteria when deployed on a programmable logic device. From the relative suitability of the configuration bitstreams, next-generation data for the data structures are generated using a genetic algorithm applied to sets of data. In the various embodiments, the configuration bitstreams eliminate resource contentions, selectively eliminate asynchronous behavior, include built-in test circuits, and are relocatable. Multiple populations of configuration bitstreams can evolve in parallel over a network.
    Type: Grant
    Filed: June 17, 1999
    Date of Patent: April 23, 2002
    Assignee: Xilinx, Inc.
    Inventors: Delon Levi, Steven A. Guccione
  • Patent number: 6376131
    Abstract: A reticle that is modified to prevent bridging of the masking material (e.g., chrome) between portions of the lithographic mask pattern during an integrated circuit fabrication process. According to a first aspect, the modification involves electrically connecting the various portions of the lithographic mask pattern that balance charges generated in the portions during fabrication processes. In one embodiment, sub-resolution wires that extend between the lithographic mask pattern portions facilitate electrical conduction between the mask pattern portions, thereby equalizing dissimilar charges. In another embodiment, a transparent conductive film is formed over the lithographic mask pattern to facilitate conduction. In accordance with a second aspect, the modification involves separating the various portions of the lithographic mask pattern into relatively small segments by providing sub-resolution gaps between the various portions, thereby minimizing the amount of charge that is generated on each portion.
    Type: Grant
    Filed: April 4, 2000
    Date of Patent: April 23, 2002
    Assignee: Xilinx, Inc.
    Inventors: Jae Cho, Zhi-Min Ling, Xin X. Wu
  • Patent number: 6373279
    Abstract: A fast, space-efficient lookup table (LUT) for programmable logic devices (PLDs) in which the write decoder, read decoder and memory block of the LUT are modified to improve performance while providing a highly efficient layout. Both the write decoder and the read decoder are controlled by LUT input signals, and data signals are transmitted directly to each memory circuit of the memory block (i.e., without passing through the write decoder). Each memory circuit includes an inverter circuit connected between the memory cell and the output terminal of the memory circuit. The write decoder includes NOR gates that generate select signals used to address individual memory circuits during write operations. The read decoder includes a multiplexing circuit made up of a series of 2-to-1 multiplexers that are directly controlled by the input signals received from the interconnect resources of the PLD.
    Type: Grant
    Filed: May 5, 2000
    Date of Patent: April 16, 2002
    Assignee: Xilinx, Inc.
    Inventors: Trevor J. Bauer, Steven P. Young, Richard A. Carberry
  • Patent number: 6373779
    Abstract: A dedicated block random access memory (RAM) is provided for a programmable logic device (PLD), such as a field programmable gate array (FPGA). The block RAM includes a memory cell array and control logic that is configurable to select one of a plurality of write modes for accessing the memory cell array. In one embodiment, the write modes include a write with write-back mode, a write without write-back mode, and a read then write mode. The control logic selects the write mode in response to configuration bits stored in corresponding configuration memory cells of the PLD. The configuration bits are programmed during configuration of the PLD. In one variation, the control logic selects the write mode in response to user signals. In a particular embodiment, the block RAM is a dual-port memory having a first port and a second port. In this embodiment, the first and second ports can be independently configured to have different (or the same) write modes.
    Type: Grant
    Filed: May 19, 2000
    Date of Patent: April 16, 2002
    Assignee: Xilinx, Inc.
    Inventors: Raymond C. Pang, Steven P. Young
  • Patent number: 6369608
    Abstract: Method and apparatus for preconditioning and in-use conditioning of transistors formed on a semiconductor-on-insulator structure is described. More particularly, transistors of a programmable logic device (PLD), such as a field programmable gate array (FPGA), are preconditioned to take advantage of charge accumulation owing to a “floating body” effect. This preconditioning takes a form of switching transistors on and off prior to customer operation. Accordingly, semiconductor-on-insulator transistors accumulate charge during this switching period, so when customer operation takes place, transistor switching times are less variable over a period of operation of the PLD. Additionally, a design process and implementation is described for identification and in-use conditioning of transistors that may need conditioning during customer operation to control switching time variability.
    Type: Grant
    Filed: January 18, 2001
    Date of Patent: April 9, 2002
    Assignee: Xillinx, Inc.
    Inventors: Austin H. Lesea, Robert J. Francis
  • Patent number: 6366117
    Abstract: It is sometimes desirable to encrypt a design for loading into a PLD so that an attacker may not learn and copy the design as it is being copied into the PLD. According to the invention, the encrypted design is decrypted by a key or keys within the PLD that are preserved when power is removed by either being stored in nonvolatile memory or by being backed up with a battery that switches into operation when the power is removed from the PLD.
    Type: Grant
    Filed: November 28, 2000
    Date of Patent: April 2, 2002
    Assignee: Xilinx, Inc.
    Inventors: Raymond C. Pang, Jennifer Wong, Scott O. Frake, Jane W. Sowards, Venu M. Kondapalli, F. Erich Goetting, Stephen M. Trimberger, Kameswara K. Rao
  • Patent number: 6366128
    Abstract: Described are systems for producing differential logic signals. These systems can be adapted for use with different loads by programming one or more programmable elements. One embodiment includes a series of driver stages, the outputs of which are connected to one another. The driver stages turn on successively to provide increasingly powerful differential amplification. This progressive increase in amplification produces a corresponding progressive decrease in output resistance, which reduces the noise associated with signal reflection. The systems can be incorporated into programmable IOBs to enable PLDs to provide differential output signals.
    Type: Grant
    Filed: September 5, 2000
    Date of Patent: April 2, 2002
    Assignee: Xilinx, Inc.
    Inventors: Atul V. Ghia, Suresh M. Menon, David P. Schultz
  • Patent number: 6363517
    Abstract: A system and method for evolving configuration bitstreams for a programmable logic device are disclosed. A plurality of data structures having respective sets of data are established. From the sets of data, respective configuration bitstreams are generated, wherein the sets of data are mapped to positions in the bitstreams. The configuration bitstreams are then evaluated for relative suitability to meet predetermined criteria when deployed on a programmable logic device. From the relative suitability of the configuration bitstreams, next-generation data for the data structures are generated using a genetic algorithm applied to sets of data. In the various embodiments, the configuration bitstreams eliminate resource contentions, selectively eliminate asynchronous behavior, include built-in test circuits, and are relocatable. Multiple populations of configuration bitstreams can evolve in parallel over a network.
    Type: Grant
    Filed: June 17, 1999
    Date of Patent: March 26, 2002
    Assignee: Xilinx, Inc.
    Inventors: Delon Levi, Steven A. Guccione
  • Patent number: 6363519
    Abstract: A system and method for evolving configuration bitstreams for a programmable logic device are disclosed. A plurality of data structures having respective sets of data are established. From the sets of data, respective configuration bitstreams are generated, wherein the sets of data are mapped to positions in the bitstreams. The configuration bitstreams are then evaluated for relative suitability to meet predetermined criteria when deployed on a programmable logic device. From the relative suitability of the configuration bitstreams, next-generation data for the data structures are generated using a genetic algorithm applied to sets of data. In the various embodiments, the configuration bitstreams eliminate resource contentions, selectively eliminate asynchronous behavior, include built-in test circuits, and are relocatable. Multiple populations of configuration bitstreams can evolve in parallel over a network.
    Type: Grant
    Filed: June 17, 1999
    Date of Patent: March 26, 2002
    Assignee: Xilinx, Inc.
    Inventors: Delon Levi, Steven A. Guccione
  • Patent number: 6362650
    Abstract: One or more columns of multi-function tiles are positioned between CLB tiles of the FPGA array. Each multi-function tile includes multiple function elements that share routing resources. In one embodiment, a multi-function tile includes a configurable, dual-ported RAM and a multiplier that share routing resources of the multi-function tile. The RAM includes first and second input ports coupled to first and second input data buses, respectively, and includes first and second output ports coupled to first and second output data buses, respectively. The multiplier includes first and second operand ports coupled to receive operands from the first and second input data buses, and in response thereto provides a product. In one embodiment, the most significant bits (MSBs) of the product are selectively provided to the first output data bus using bus multiplexer logic, and the least significant bits (LSBs) of the product are selectively provided to the second output data bus using bus multiplexer logic.
    Type: Grant
    Filed: May 18, 2000
    Date of Patent: March 26, 2002
    Assignee: Xilinx, Inc.
    Inventors: Bernard J. New, Steven P. Young