Patents by Inventor Michael A. Ziegerhofer

Michael A. Ziegerhofer 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: 7757141
    Abstract: A method for testing integrated circuits (ICs) by automatically extending addressing for shared array built-in self-test (BIST) circuitry, includes polling a plurality of memories to determine which of the plurality of memories are sharing a first comparison tree and mapping a shared array BIST address space to each of the plurality of memories using the first comparison tree. Additionally, the method includes estimating a shared array BIST completion time corresponding to a most significant bits of a maximum total memory address size under test, reconfiguring the shared array BIST circuitry to accommodate the estimated shared array BIST completion time and testing the plurality of memories sharing the first comparison tree.
    Type: Grant
    Filed: March 26, 2008
    Date of Patent: July 13, 2010
    Assignee: International Business Machines Corporation
    Inventors: Valerie H. Chickanosky, Kevin W. Gorman, Michael R. Ouellette, Michael A. Ziegerhofer
  • Publication number: 20090327620
    Abstract: Disclosed is a semiconductor chip with a digital integrated circuit, such as a memory device (e.g., static random access memory (SRAM) arrays, dynamic random access memory (DRAM) arrays, content addressable memory (CAM) arrays, etc), that can be selectively operated in either a functional mode or in a performance screening mode. In the functional mode, a first signal supplied by an external signal generator is used to activate a first device in the circuit and, in response, a second device in the circuit outputs a data output signal. In the performance screening mode, a second signal is internally generated by an internal signal generator based on the data output signal. This second signal is then used to activate the first device in the circuit and, in response, the second device outputs the data output signal.
    Type: Application
    Filed: June 27, 2008
    Publication date: December 31, 2009
    Inventors: Igor Arsovski, David J. Wager, Michael A. Ziegerhofer
  • Publication number: 20090249146
    Abstract: A method for testing integrated circuits (ICs) by automatically extending addressing for shared array built-in self-test (BIST) circuitry, includes polling a plurality of memories to determine which of the plurality of memories are sharing a first comparison tree and mapping a shared array BIST address space to each of the plurality of memories using the first comparison tree. Additionally, the method includes estimating a shared array BIST completion time corresponding to a most significant bits of a maximum total memory address size under test, reconfiguring the shared array BIST circuitry to accommodate the estimated shared array BIST completion time and testing the plurality of memories sharing the first comparison tree.
    Type: Application
    Filed: March 26, 2008
    Publication date: October 1, 2009
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Valerie H. CHICKANOSKY, Kevin W. Gorman, Michael R. Ouellette, Michael A. Ziegerhofer
  • Publication number: 20090099828
    Abstract: Disclosed are embodiments of a design structure for reducing and/or eliminating mismatch. The embodiments sample the bias of one or more circuit sub-components that require a balanced state (e.g., sampling the bias of the cross-coupled transistors in each memory cell and/or sense amp in a memory array) before chip burn-in, by initiating a burn-in process during which an individually selected state is applied to each of the devices in the circuit. This fatigues the devices away from their preferred states and towards a balanced state. The bias is periodically reassessed during the burn-in process to avoid over-correction. By using this method both memory cell and sense-amplifier mismatch can be reduced in memory arrays, resulting in smaller timing uncertainty and therefore faster memories.
    Type: Application
    Filed: October 12, 2007
    Publication date: April 16, 2009
    Inventors: Igor Arsovski, Harold Pilo, Michael A. Ziegerhofer
  • Publication number: 20090016129
    Abstract: A design structure which enables e-fuse memory repair. The design structure uses a compressed bit string to generate another bit string based on a select value. The select value provides instructions to an encoding logic element, which generates a second bit string. For example, the select value may instruct the encoding logic to create a duplicate copy of each bit in the compressed bit string to generate a 2n-bit string. Once the fuses are programmed using the second bit string, the fuse values are read out as a third string, which is decoded by a decoding logic element according to the select value, thereby improving memory repair.
    Type: Application
    Filed: July 10, 2007
    Publication date: January 15, 2009
    Inventors: Darren Anand, Michael Ouellette, Michael Ziegerhofer
  • Publication number: 20080219069
    Abstract: Disclosed are embodiments of a method for reducing and/or eliminating mismatch. The embodiments sample the bias of one or more circuit sub-components that require a balanced state (e.g., sampling the bias of the cross-coupled transistors in each memory cell and/or sense amp in a memory array) before chip burn-in, by initiating a burn-in process during which an individually selected state is applied to each of the devices in the circuit. This fatigues the devices away from their preferred states and towards a balanced state. The bias is periodically reassessed during the burn-in process to avoid over-correction. By using this method both memory cell and sense-amplifier mismatch can be reduced in memory arrays, resulting in smaller timing uncertainty and therefore faster memories.
    Type: Application
    Filed: March 9, 2007
    Publication date: September 11, 2008
    Inventors: Igor Arsovski, Harold Pilo, Michael A. Ziegerhofer
  • Publication number: 20060239088
    Abstract: Integrated circuit memory is tested to discover defective memory elements. To replace the defective memory elements, spare memory elements are selected and a string is generated to indicate which ones of the spares replace which ones of the defective memory elements. The number of bits of the string depend upon how many of the memory elements are defective. Although a certain number of the memory elements are defective, which determines the number of the string bits, nevertheless, a number of fuses to program on the integrated circuit is determined responsive to how many fuses are available for programming relative to the number of the binary string bits. That is, if more fuses are available than a certain threshold number relative to the number of string bits (as is preferred), then more than the threshold number are programmed. If not, then only that certain threshold number of fuses are programmed.
    Type: Application
    Filed: April 26, 2005
    Publication date: October 26, 2006
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Darren Anand, Michael Ouellette, Michael Ziegerhofer