International Business Machines Corporation

Siemens Aktiengesellschaft

Silicon Access Networks, Inc.

Kabushiki Kaisha Toshiba

Silicon Access Technology, Inc.

Hing Wong

Toshiaki Kirihata

John Kenneth DeBrosse

Jack Allan Mandelman

John Edward Cronin

Bozidar Krsnik

Pai-Hung Pan

Brian J Machesney

Yohji Watanabe

Juhan Kim

Jeffrey P Gambino

Louis L Hsu

Steven J Holmes

Edmund Juris Sprogis

Wayne Frederick Ellis

Bomy A Chen

Matthew R Wordeman

Gerhard Mueller

Subramani Kengeri

Michael D Armacost

Johann Alsmeier

Mark A Jaso

Paul E Bakeman, Jr

Hans-Oliver Joachim

Ali Massoumi

Michael M Armacost

A memory architecture is disclosed that employs multiple column redundancies which provide multiple options for replacing a defective global odd or even bit line. Each column memory has two multiplexers, one for selecting a global odd bit line and another for selecting a global even bit line. Two or more column redundancies are coupled to each of the multiplexer in the column memory. In a first embodiment, the global odd and even bit lines are connected through odd and even sense amps in a regular column. In a second embodiment, the global odd bit line in a regular column connects through odd sense amps, while the global even bit line in the regular column connects through even sense amps. In a third embodiment, two or more sets of redundancy columns are commonly coupled to a left adjacent regular column and a right adjacent regular column.

Structure and method of a column redundancy memory

The invention discloses a low-power ternary CAM by utilizing four encoded comparand datalines, C,, C,, C,, and C,in a twin ternary cell. The twin ternary cell is a composite of two ternary CAM bits. The two binary CAM bits are coded so that only one of four comparand datalines is toggled during a compare operation. The encoded data is stored and used for comparison. In one embodiment, the four possible states for the 2 bit comparands are coded as 0001, 0010, 0100, and 1000.

Structure and method of an encoded ternary content addressable memory (CAM) cell for low-power compare operation

The present invention discloses a parallel test circuit and method for testing even bit line and odd bit line in a memory block simultaneously. The parallel test circuit comprises an even test circuit for testing an even bit line and an odd test circuit for testing an odd bit line. The parallel test circuit also includes a write circuit for writing data to a bit line, a read circuit including a data sense amp, an output buffer, and a comparator. Furthermore, the present invention provides the capability to conduct disturbance test in neighboring even and odd cells.

Parallel test circuit and method for wide input/output DRAM

A negative wordline DRAM array having n groups of m wordlines, in which one group is driven by a group decoder circuit (having a voltage swing between ground and a circuit high voltage (2 v)) and one driver circuit in each group is exposed to a boosted wordline high voltage (2.8 v) greater than the circuit high voltage, in which the wordline driver circuits have an output stage comprising a standard nfet in series with a high threshold voltage pfet, so that, during activation, the unselected driver circuits exposed to the boosted wordline high voltage have a very low leakage through the pfet, while the selected driver circuit has a high but tolerable leakage (2 &mgr;A) because Vqs on the nfet is nearly at the nfet threshold. The net active power from the entire array is less than that of a conventional configuration due to the reduced voltage swing, while the number of transistors exposed to high voltage stress is reduced from 9 to 1 and the number of buffer nfets required to reduce voltage drop across an active nfet is reduced from 8 to 1.

High performance CMOS word-line driver

Provision of differential etching of layers by, for example, an etch stop layer or implantation, allows a second trough etch to be performed in accordance with a block-out mask (which does not require high accuracy of registration) to provide troughs or recesses of different depths in layers of insulator. When the recesses or troughs are filled by metal deposition and patterned by planarization in accordance with damascene processing, structurally robust conductors of differing thicknesses may be achieved and optimized to enhance noise immunity and/or signal propagation speed in different functional regions of an integrated circuit such as the so-called array and support portions of a dynamic random access memory.

Fabrication of interconnects with two different thicknesses

DRAM with column slices improves circuit redundancy. Slices have global column length, and memory is divided in groups with size of redundancy columns having slices. Failure detected among slices of corresponding storage is replaced by corresponding redundancy column slice, such that column redundancy division is in vertical column direction. Column includes global data line shared by column slices and multiple blocks. Redundant column is added to memory array, and redundant control circuits or comparator are proximate to data sense amplifiers. Defective column address are provided to controller through non-volatile memory, or laser-blown or electrically-programmable fuses. When column address is presented, incoming address is compared with stored address, such that select data is output on redundant data line when equal addresses (i.e., hit detect), or normal data is output when unequal addresses (i.e., 'miss' detected).

Column redundancy based on column slices

Disclosed is a semiconductor memory having a hierarchical bit line and/or word line architecture. In one embodiment, a memory having a hierarchical bit line architecture, particularly suitable for cells smaller than 8F.sup.2, includes a master bit line pair in each column, including first and second master bit lines with portions vertically spaced from one another. The first and second master bit lines twist with respect to one another in the vertical direction such that the first master bit line alternately overlies and underlies the second master bit line. A plurality of local bit line pairs in each column are coupled to memory cells, with at least one of the local bit lines coupled to a master bit line. In other embodiments, hierarchical word line configurations are disclosed including master word lines, sub-master word lines, and local word lines, electrically interconnected to one another via either switches, electrical contacts, or electrical circuits.

Semiconductor memory having hierarchical bit line and/or word line

A method and apparatus for repairing a semiconductor memory device. A row redundancy replacement arrangement is provided to repair the memory device consisting of a first plurality of redundant true word lines and a second plurality of redundant complement word lines to simultaneously replace the same first number of first normal word lines and the same second number of the normal complement word lines. An address reordering scheme, preferably implemented as a word line selector circuit and controlled by redundancy control logic and address inputs, allows the redundant true (complement) word lines to replace the normal true (complement) word lines when making the repair. The redundancy replacement arrangement ensures that consistency of the bit map is maintained at all times, irrespective whether the memory device operates in a normal or in a redundancy mode. This approach introduces an added flexibility of incorporating the redundancy replacement without affecting the column access speed.

Method and apparatus for redundancy word line replacement in a

A circuit and method of using a test mode to control the timing of an internal signal using an external control in an integrated circuit. The test mode is designed such that the timing of the internal signal is derived from the external control which can be arbitrarily controlled by a tester. The external signal can be applied to an existing pin for chip control, provided that there is no conflict between the test mode and the operation of the integrated circuit.

Circuit and method to externally adjust internal circuit timing

A method for generating a floating bitline test mode using digitally controllable bitline equalizers is provided. The method utilizes digitally controlled dummy timing cycles to detect a leaky bitline during the floating bitline test mode. A negative pulsed TEST signal is generated to cause the bitline equalizers to go low and cause the floating bitline state. The implementation of dummy timing cycles eliminates the need for additional external control of internal timings during a bitline test mode. Upon the termination of the dummy timing cycle, the normal read operation continues without interruption.

Floating bitline test mode with digitally controllable bitline equalizers

A semiconductor structure having electrical conductors positioned over each other, but electrically isolated from each other, is disclosed. The lower conductor has a recess in its upper surface, and the recess is at least partially filled with an oxide-type material, thereby isolating the lower conductor from the upper conductor. These conductors would normally contact each other because of the somewhat imprecise patterning and etching steps used to fabricate a multitude of conductive elements, e.g., in a very dense semiconductor structure. Stacked capacitor cells incorporating this structure are also disclosed.

Stacked electrical device having regions of electrical isolation and

A semiconductor structure to prevent gate wrap-around and corner parasitic leakage comprising a semiconductor substrate having a planar surface. A trench is located in the substrate, the trench having a sidewall. An intersection of the trench and the surface forms a corner. A dielectric lines the sidewall of the trench. And, a corner dielectric co-aligned with the corner extends a subminimum dimension distance over the substrate from the corner.

Method of making corner protected shallow trench field effect transistor

Row redundancy control circuits which effectively reduce design space are arranged parallel to word direction and are arranged at the bottom of the redundancy block. This architecture change makes it possible to effectively lay out the redundancy control block by introducing (1) split-global-bus shared with local row redundancy wires, (2) half-length-one-way row redundancy-wordline-enable-signal wires which allows space saving, and (3) distributed wordline enable decoders designed to take advantage of the saved space. An illegal normal/redundancy access problem caused by the address versus timing skew has also been solved. The timing necessary for this detection is given locally by using its adjacent redundancy match detection. This allows the circuit to operate completely as an address driven circuit, resulting in fast and reliable redundancy match detection. In addition, a sample wordline enable signal (SWLE) is generated by using row redundancy match detection. One two-input OR gate allows the time at which SWLE sets sample wordline (SWL) to be the same as the time at which wordline enable (WLE) signal sets wordline (WL). The time at which SWLE sets SWL remains consistent regardless of mode, eliminating the existing reliability concern. This two-input OR gate combined with row redundancy match detection works as an ideal sample wordline enable generator.

Row redundancy block architecture

A method of testing a RAM. The RAM array is arranged in rows and columns. The rows are grouped into word line groups. The method includes the steps of: a) asserting an array select signal; b) selecting a group of rows in the array; c) selecting at least one row of the selected group of rows; and, d) repeating steps b and c until all of the groups are selected. Array Sense Amps may be set when the first group is selected and remain set until the last group is selected. In one test, word lines in all of the selected rows are activated and remain activated until the final selected row is selected. In a second test, word lines in selected groups are toggled with RAS. If a group contains a known defective word line, that group is either not addressed or its selection is disabled. In each selected group, one row, alternating rows or, all of the rows may be selected.

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Norwalk, CT, United States of America

Hing Wong