International Business Machines Corporation

Erik A Nelson

William R Corbin

Donald Lawrence Wheater

Jeffrey H Dreibelbis

Thomas E Obremski

John Edward Barth, Jr

Steven William Tomashot

David G Chapman

Timothy E Fiscus

Alan D Norris

Laura S Chadwick

Toshiharu Saitoh

David P Monty

Michael Richard Ouellette

Harold Pilo

Marc Douglas Knox

David A Grosch

Brian C Noble

William E Corbin, Jr

Brian Robert Kessler

Method and apparatus for margin testing integrated circuits. The method includes selecting a clock frequency, an operating temperature range and a power supply voltage level for margin testing an integrated circuit wherein one or more of the clock frequency, the operating temperature range and the power supply voltage level is outside of the normal operating conditions of the integrated circuit; applying an asynchronously time varying power supply voltage set to the selected power supply voltage level to the integrated circuit; running the integrated circuit chip at the selected clock frequency and maintaining the integrated circuit within the selected temperature range; applying a continuous test pattern to the integrated circuit; and monitoring the integrated circuit for fails.

Methods and apparatus for margin testing integrated circuits using asynchronously timed varied supply voltage and test patterns

An approach that provides reference level generation with offset compensation for a sense amplifier is described. In one embodiment, an arbitrary reference level is generated to provide an offset that compensates for device mismatch and voltage threshold of a sense amplifier.

Reference level generation with offset compensation for sense amplifier

A system for testing a DRAM includes DRAM blocks, the system further includes a processor based built-in self test system for generating a test data pattern, for each DRAM block, performing a write of the test data pattern into the DRAM block, performing a pause for a predetermined period of time, and performing a read of a resulting data pattern from the DRAM block. For each DRAM block, the performing the write of the test pattern into the DRAM block is performed before the performing the pause for the predetermined period of time, and the performing the read of the resulting data pattern from the DRAM block is performed after the performing the pause for the predetermined period of time, and at least a portion of the pause for the predetermined period of time of two or more the DRAM blocks overlap in time.

Method for testing embedded DRAM arrays

Technique to perform logic and embedded memory tests using logic scan chain testing procedures in parallel with memory built in self test (BIST). This is accomplished with a combination of voltage isolation between memory and logic segments, and isolation between logic and memory test clocks. A test algorithm is introduced to enable and disable the scan chain operation during BIST operation.

Testing logic and embedded memory in parallel

A method and system for testing an embedded DRAM that includes DRAM blocks. The method including: generating a test data pattern in a processor based BIST system, for each DRAM block, performing a write of the test data pattern into the DRAM block, performing a pause for a predetermined period of time, and performing a read of a resulting data pattern from the DRAM block; where for each DRAM block, the write of the test data pattern into the DRAM block is performed before the pause, and the read of the resulting data pattern from each DRAM block is performed after the pause; where at least a portion of the pause of two or more of the DRAM blocks overlap in time; and for each DRAM block comparing the test data pattern to the resulting data pattern.

Multiple fuse decompression serial bitstreams support an auxiliary fuseblow capability utilizing on-chip storage and providing a composite capability of embedded memory address/data failure information. A multiple repair capability has an improved compression algorithm to compress fuse data with system level soft-set redundancy, and lends itself to self-repair design, and to provide repairs for temperature sensitive fails. An instruction based tester interface in a fuse control provides shift loaded instructions in which the sequence of test and fuse repair operations is variable to provide flexibility in the manufacturing, test and repair operations.

Method and system for merging multiple fuse decompression serial bitstreams to support auxiliary fuseblow capability

A method for testing the data strobe window (DQS) and data valid window (tDV) of a memory device (e.g., a DDR-type memory device) using the window strobe of a testing system.

Method for guaranteeing a minimum data strobe valid window and a minimum data valid window for DDR memory devices

To overcome these problems, the present invention generates two window strobes and uses the two window strobes to determine if skew between two signals meets predetermined criteria. One of the window strobes is used to test one of the signals, and the other window strobe is generated relative to the first window strobe. The second window strobe tests the other signal (or signals, if they are data signals). From the tests of the two window strobes, it can be determined if the skew between the first and second signals meets predetermined criteria. In particular, the two window strobes are placed relative to each other and to the signals being tested in such a way that when both window strobes indicate passing conditions, skew between the two signals is guaranteed.

Method for testing and guaranteeing that skew between two signals meets predetermined criteria

A method and circuit for a self timed DRAM. The circuit includes interlock circuits coupled to an extension of the DRAM. The extension does not store &ldquo;real&rdquo; data but mimics the operations of the DRAM. The interlock circuits, in conjunction with the extension monitor and control read and write timings of the DRAM and self adjust these timings via feedback. To properly track DRAM cell timings, the interlock circuits and extension use the same cell design and load conditions as the DRAM. The method includes: activating a wordline and reference wordline, interlocking the sense amplifiers, column select and write back functions of the primary DRAM array by monitoring the identical reference cells and the state of the bitline in the extension DRAM array.

Self timing interlock circuit for embedded DRAM

A method and structure for the invention includes an integrated memory structure having a built-in test portion. The integrated memory structure has memory cells, bitlines and wordlines connected to the memory cells, wordline decoders connected to a plurality of the wordlines, bitline restore devices connected to the bitlines for charging the bitlines during read and write operations, and a clock circuit connected to the wordlines. During a test mode the wordline decoders simultaneously select multiple wordlines that the bitline restore devices maintain in an active state and the clock circuit maintains th multiple wordlines and the bitline restore devices in an active state for a period in excess of a normal read cycle. The invention also includes transistors which are connected to the memory cells. The transistors include bitline contacts which are stressed during the test mode.

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Waterbury, VT, United States of America

Erik A Nelson