Patents Represented by Attorney Robert A. Walsh
-
Patent number: 6496398Abstract: The present invention relates to content addressable memory (CAM), particularly, to a CAM having its memory array, which contains a plurality of memory locations, being divided into at least a first and a second memory block (100, 102), whereby the first and second memory block (100, 102) are formed by a first and second portion of each of said memory locations, respectively. The CAM further comprises a first set of compare lines (115) and a first set-of match lines (116) associated to said first memory block (100), and a second set of compare lines (117) and a second set of match lines (118) associated to said second memory block (102), and pre-charge units (112, 114) for charging said match lines before a comparison operation. The present invention provides an improved CAM which allows flagging of memory locations of which the content only partially matches a given comparison value.Type: GrantFiled: December 6, 2001Date of Patent: December 17, 2002Assignee: International Business Machines CorporationInventors: Gerhard Hellner, Rolf Sautter, Otto Martin Wagner
-
Patent number: 6492852Abstract: A delay locked loop circuit for conserving power on a semiconductor chip is provided. The circuit includes a delay chain circuit responsive to a clock input signal for generating an output clock signal having a selectively adjustable delay at an output circuit; a feedback loop circuit connects to and controls said delay chain circuit; and a pre-divider circuit connected to said delay chain circuit, wherein said pre-divider circuit is configured to disable the delay chain circuit when the output clock signal is inactive and the memory device is in an idle state (i.e., all banks closed).Type: GrantFiled: March 30, 2001Date of Patent: December 10, 2002Assignee: International Business Machines CorporationInventor: Timothy E. Fiscus
-
Patent number: 6489223Abstract: Different symmetrical and asymmetrical devices are formed on the same chip using non-critical block masks and angled implants. A barrier is selectively formed adjacent one side of a structure and this barrier blocks dopant implanted at an angle toward the structure. Other structures have no barrier or have two barriers. Source and drain engineering can be performed for LDD, halo, and other desired implants.Type: GrantFiled: July 3, 2001Date of Patent: December 3, 2002Assignee: International Business Machines CorporationInventors: Terence B. Hook, Randy W. Mann
-
Patent number: 6487691Abstract: A Reed-Solomon decoder that can correct t errors or fewer which includes: a syndrome calculation circuit for calculating syndromes Sj (J=0, 1, . . . , 2t−1) using the first codeword Yi (i=0, 1, . . . , n−1) (so-called received codeword) that may include errors; and a coefficient calculation circuit for, by using the syndromes Sj, calculating coefficients &Lgr;k (k=1, . . . , e) of an error-locator polynomial. The coefficients &Lgr;k correspond in number to e estimated errors (e≦t<n). The syndromes Sj, calculating coefficients Er1 (1=0, . . . , ê) (ê can be as small as O(e)) of an error polynomial, and the coefficients Er1 correspond in number to the e estimated errors.Type: GrantFiled: September 22, 1999Date of Patent: November 26, 2002Assignee: International Business Machines CorporationInventors: Yasunao Katayama, Sumio Morioka
-
Patent number: 6487701Abstract: A system and method are described for separating the bulk connections for FETs on a semiconductor wafer from the supply rails, testing the wafer to determine if a shift in the threshold voltage, VT, of certain devices within the wafer, as defined by the bulk-wells, can remove an AC defect in the IC circuit, and tailoring the voltage or voltages applied to the bulk nodes, post-manufacture, such that the integrated circuit meets its performance targets or is sorted to a more valuable performance level. The method requires generating a gate level netlist of the IC's circuitry and performing timing calculations on these circuit netlists using static timing analyses, functional delay simulations, circuit activity analyses, and functional performance testing. The failures are then correlated to respective IC circuits, worst case slack circuits are investigated, and proposed changes to the threshold voltages are employed in the hardware.Type: GrantFiled: November 13, 2000Date of Patent: November 26, 2002Assignee: International Business Machines CorporationInventors: Alvar A. Dean, Jerry D. Hayes, Joseph A. Iadanza, Emory D. Keller, Sebastian T. Ventrone
-
Patent number: 6483350Abstract: A sense-amplifying circuit 10 which comprises a pair of inverters (TP0, TN0, TP1 and TN1), wherein an output of each inverter is connected to an input of the other inverter, drains of sensing transistors TN2 and TN3 are respectively connected to each source of the pair of inverters in series, the gates of both sensing transistors TN2 and TN3 are connected to differential input signal lines 12 and 14, and the sources of both sensing transistors TN2 and TN3 are connected through a common node with a transistor TN4, which works not only as a constant current source but also as an operation switch for the sense-amplifying circuit.Type: GrantFiled: September 10, 1999Date of Patent: November 19, 2002Assignee: International Business Machines CorporationInventors: Hisatada Miyatake, Yotaro Mori, Masahiro Tanaka
-
Patent number: 6477615Abstract: In a CAM having valid cells, an idle word is detected and outputted by using the data in the valid cells and an address encoder. A detection circuit of an idle word for a content addressed memory having valid cells 15, which includes a unit 19 for supplying the output (valid 16) of the valid cell 15 to an address encoder 18 in response to an idle word detection signal IWD.Type: GrantFiled: January 26, 2000Date of Patent: November 5, 2002Assignee: International Business Machines CorporationInventor: Masahiro Tanaka
-
Patent number: 6467053Abstract: A Synchronous DRAM memory test assembly that converts a normal PC or Workstation with a synchronous bus into a memory tester. The test assembly may be split into two segments: a diagnostic card and an adapter card to limit mechanical load on the system socket as well as permit varying form factors. This test assembly architecture supports memory bus speeds of 66 MHz and above, and provides easy access for a logic analyzer. The test assembly supports Registered and Unbuffered Synchronous DRAM products. The test assembly permits good and questionable synchronous modules to be compared using an external logic analyzer. It permits resolution of in-system fails that occur uniquely in system environments and may be otherwise difficult or impossible to replicate.Type: GrantFiled: June 28, 1999Date of Patent: October 15, 2002Assignee: International Business Machines CorporationInventors: Brian J. Connolly, Steven A. Grundon, Bruce G. Hazelzet, Mark W. Kellogg, James R. Mallabar
-
Patent number: 6458020Abstract: A recirculation mechanism is used to force slurry toward the center of a platen used for chemical-mechanical polishing. The recirulator captures the slurry that would otherwise be flung from a rotating platen because of centrifugal force. The captured slurry is forced upwardly away from the surface of the platen and toward the center of the platen to recycle the slurry.Type: GrantFiled: November 16, 2001Date of Patent: October 1, 2002Assignee: International Business Machines CorporationInventors: Jeffrey A. Brigante, Thomas L. Conrad, David J. Fontaine, Rock Nadeau, Paul H. Smith, Jr., Theodore G. van Kessel
-
Patent number: 6458634Abstract: A method of substantially reducing charge build-up in a SOI device is provided. The method includes depositing a dielectric material on a surface of a semiconductor structure which includes at least silicon-on-insulator (SOI) devices therein. Next, a first conductive material is deposited on the dielectric material and then holes are drilled through the conductive material and the dielectric insulating material. Each hole is filled with a second conductive material, and thereafter selective portions of the first conductive material are removed to form contact pads for further probing. The method is especially useful in focused ion beam (FIB) drilling.Type: GrantFiled: April 18, 2001Date of Patent: October 1, 2002Assignee: International Business Machines CorporationInventor: Keith C. Stevens
-
Patent number: 6455336Abstract: A design and burn-in technique that effectively reduces power consumption during burn-in for devices with high power consumption as a result of shrinking voltages, high instantaneous current, subthreshold leakage and high currents at stress conditions. Three methods of reducing power consumption during burn-in are disclosed in detail: (1) completely separate power grids, (2) isolated grids during burn-in, and (3) isolated grids for MTCMOS used during burn-in. Each technique provides a method of segmenting the power supply of a chip and controlling which segment of the chip is stressed based on which segment is ‘powered on’. Those segments not being stressed are ‘shutoff’ so as to reduce power consumption.Type: GrantFiled: August 27, 2001Date of Patent: September 24, 2002Assignee: International Business Machines CorporationInventors: Zachary E. Berndlmaier, Mark R. Bilak, Norman J. Rohrer
-
Patent number: 6452832Abstract: To provide a DRAM circuit capable of achieving a high speed write operation even when the write operation is accompanied with a write masking operation, and a method of controlling the same. A DRAM circuit of the present invention has a novel column switch for connecting a bit line pair and a data line pair via a sense amplifier. The novel column switch has a function to separate a bit line pair corresponding to a selected data line pair during the write mask operation. As a result, even if the column switch is made to be ON before the it line pair is sufficiently amplified by the sense amplifier, there is no fear that data on the bit line pair is destroyed due to a malfunction of the sense amplifier, thus making it possible to achieve a high speed write operation without depending on whether the write masking operation in the DRAM circuit is performed or not.Type: GrantFiled: February 19, 2001Date of Patent: September 17, 2002Assignee: International Business Machines CorporationInventor: Kohji Hosokawa
-
Patent number: 6452848Abstract: A programmable data generator for generating input test data to be applied to a semiconductor memory array is disclosed. In an exemplary embodiment of the invention, the data generator includes a programmable address scramble register which has a plurality of storage locations associated therewith. The plurality of storage locations corresponds to array address bits associated with an address generator. A first exclusive OR (XOR) logic structure is coupled to the address generator and the address scramble register, wherein the first XOR logic structure generates an address-dependent, data scramble output signal that ultimately determines a data pattern to be applied to the memory array.Type: GrantFiled: September 12, 2001Date of Patent: September 17, 2002Assignee: International Business Machines CorporationInventors: Thomas E. Obremski, Jeffrey H. Dreibelbis, Peter O. Jakobsen
-
Patent number: 6445744Abstract: A highspeed bus architecture featuring low signal levels, differential sensing, and zero net current over a four wire transmission line cluster. The bus system comprises a system for transmitting n bits of data and includes an encoding system for receiving the n bits of data and outputting m signals wherein the m signals have a zero net current, m transmission lines for carrying the m signals, and a decoding system for receiving the m signals and converting the m signals back into n bits of data, using differential amplifiers.Type: GrantFiled: January 4, 1999Date of Patent: September 3, 2002Assignee: International Business Machines CorporationInventors: Timothy Jay Dell, Wilbur David Pricer
-
Patent number: 6441632Abstract: A spring probe (pogo pin) contactor for testing semiconductor devices with pogo pins within a spring probe contactor is disclosed. The contactor device has a plurality of pogo pins extending therefrom for testing the semiconductor device. A surface of the spring pogo pin contactor has an array of apertures for receiving each pogo pin for contacting of the plurality of contacts on the device under test in order to make contact with and compress the pogo pins. A three piece assembly is used to accurately position the pogo pins for ease of construction and repair.Type: GrantFiled: April 9, 2001Date of Patent: August 27, 2002Assignee: International Business Machines CorporationInventors: George C. Correia, Howard F. Garcia
-
Patent number: 6438051Abstract: A stabilized direct sensing memory architecture which provides Process, Voltage and Temperature (PVT) compensation in a memory array to a direct sense circuit to increase the manufacturing yield thereof, and to extend the operating voltage and temperature ranges thereof independent of manufacturing tolerances. A single-ended sense amplifier structure has a common source NFET amplifier with an adjustable current source load provided by a PFET. The PFET current source is automatically adjusted to place the NFET amplifier in an operating range to provide maximum amplification of a small signal superimposed on a bitline precharge voltage. A mimic bias generator circuit provides this operating point adjustment, and realizes a direct, single-ended sensing operation using a small number of transistors.Type: GrantFiled: May 31, 2001Date of Patent: August 20, 2002Assignee: International Business Machines CorporationInventors: John A. Fifield, Wing K. Luk, Daniel W. Storaska
-
Patent number: 6428300Abstract: A method of encapsulating a workpiece, particularly a microelectronic device, to achieve a very thin encapsulating layer and reduce the finished device size. The method includes positioning the workpiece in the mold cavity of a mold capable of reducing its volume while the mold compound is in a liquid state from a first volume, where mold compound may be easily added without creating voids, to a second smaller volume which defines the finished workpiece size. The second volume is below the size which would permit the void-free encapsulation of the workpiece in a conventional thermosetting plastic transfer molding machine. The mold may be opened in two stages to prevent damage to thin molded microelectronic devices by opening the perimeter of the mold first while the molded device is still being supported by large molding surfaces. The invention also includes the mold used in the method.Type: GrantFiled: June 7, 2001Date of Patent: August 6, 2002Assignee: International Business Machines CorporationInventors: John J. Lajza, Jr., Charles R. Ramsey, Robert M. Smith
-
Patent number: 6429730Abstract: A semiconductor circuit for providing decoupling capacitance to an integrated circuit voltage supply that includes a decoupling capacitance comprised of an array of memory cells connected in series at a node and a source of biasing voltage connected to the array of memory cells at the node for maintaining the voltage level at the node lower than the voltage level of the voltage supply.Type: GrantFiled: May 31, 2001Date of Patent: August 6, 2002Assignee: International Business Machines CorporationInventors: Russell J. Houghton, Christopher P. Miller
-
Patent number: 6426904Abstract: Wafer test and burn-in is accomplished with state machine or programmable test engines located on the wafer being tested. Each test engine requires less than 10 connections and each test engine can be connected to a plurality of chips, such as a row or a column of chips on the wafer. Thus, the number of pads of the wafer that must be connected for test is substantially reduced while a large degree of parallel testing is still provided. The test engines also permit on-wafer allocation of redundancy in parallel so that failing chips can be repaired after burn-in is complete. In addition, the programmable test engines can have their code altered so test programs can be modified to account for new information after the wafer has been fabricated. The test engines are used during burn-in to provide high frequency write signals to DRAM arrays that provide a higher effective voltage to the arrays, lowering the time required for burn-in.Type: GrantFiled: March 9, 2001Date of Patent: July 30, 2002Assignee: International Business Machines CorporationInventors: John E. Barth, Claude L. Bertin, Jeffrey H. Dreibelbis, Wayne F. Ellis, Wayne J. Howell, Erik L. Hedberg, Howard L. Kalter, William R. Tonti, Donald L. Wheater
-
Patent number: 6426657Abstract: The present invention provides a single-ended signal detection circuit (sense-amplifier) which exhibits a little power consumption and performs a high speed operation. A sense-amplifying circuit (100) detects a signal on one signal line to amplify the detected signal. A sensing switch composed of first and second switches (13, 14), each of which is connected to a source terminal of the sense-amplifying circuit and to a constant current source (15), the first switch being connected to a signal line (10) and the second switch being connected to a reference potential (Vref), wherein a driving force of the first switch is larger than that of the second switch.Type: GrantFiled: October 14, 1999Date of Patent: July 30, 2002Assignee: International Business Machines CorporationInventors: Hisatada Miyatake, Yotaro Mori, Masahiro Tanaka