Infineon Technologies Ag

Kabushiki Kaisha Toshiba

Other

Norbert Rehm

Jan Zieleman

Thomas Roehr

Joerg W Wohlfahrt

Michael Jacob

Hans-Oliver Joachim

Rath Ung

Robert C Perry

Dirk Fuhrmann

Rob Perry

Daisaburo Takashima

Tadashi Miyakawa

A programmable activate-precharge cycle are provided for a DRAM device. Activate and precharge signals associated with the activate-precharge cycle are generated on the basis of the programmed rate and precharge time with respect to an internal clock of the DRAM device. The activate and precharge signals are coupled to wordlines of the DRAM device, and switched from one wordline to another under internal or external control. One or more functions of the DRAM device are tested while the activate and precharge signals are coupled to wordline. The manner in which switching the activate and precharge signals from one wordline to another wordline is configured depending on the type of testing to be conducted.

Test mode for programming rate and precharge time for DRAM activate-precharge cycle

A random access memory including an array of memory cells configured to store memory cell data, a first circuit, and a second circuit. The first circuit is configured to compare test data and memory cell data to obtain comparison results. The second circuit is configured to compress the comparison results and store the compressed comparison results.

Random access memory including circuit to compress comparison results

A memory device and methods to exploit extra or dummy wordlines in the memory device, wherein the extra wordlines are not part of a main memory area of the memory device but, when activated, connect their attached memory cells to the bitlines of the main memory area. The extra wordlines are connected to a voltage in such a manner so as to simulate a floating wordline condition. Associated with each extra wordline is a driver circuit that connects the extra wordline to a voltage to allow it to charge up to the voltage, and subsequently disconnects the wordline from the voltage to allow it to float. While the extra wordline is floating, measurements may be made on the memory device to gather data useful for testing production memory chips for floating wordline conditions. According to another aspect, one or more extra wordlines may be activated to connect its attached memory cells to bitlines, thereby increasing the capacitance on the bitlines. This is useful during certain test mode conditions of a memory device, or on a more permanent basis to enhance the performance of the memory device.

Simulating a floating wordline condition in a memory device, and related techniques

Embodiments of the invention generally provide methods and systems for increasing the level of parallelism in testing memory devices. A set of test signals provided by a memory tester may be shared by two or more devices under test. A chip selector may be used to select at least one or all the devices sharing a given set of test signals. By sharing test signals between multiple devices, the level of parallel testing may be increased without increasing the pin count and complexity of memory testers and probe cards.

Test parallelism increase by tester controllable switching of chip select groups

A random access memory including first memory cells, second memory cells, a first voltage source, and a second voltage source. The first voltage source is configured to control the first memory cells. The second voltage source is configured to control the second memory cells. Also, the first voltage source is configured to be trimmed independently of the second voltage source to provide a first voltage that reduces leakage from the first memory cells and the second voltage source is configured to be trimmed independently of the first voltage source to provide a second voltage that reduces leakage from the second memory cells.

Random access memory including first and second voltage sources

A method and apparatus according to the present invention enable wafer chips to be configured with a single power on and off sequence and further enable a chip parameter to be adjusted during a wafer test without utilizing that sequence. In particular, each wafer chip under test is assigned a unique programmable identification. Once each chip has been assigned a corresponding identification, the chips may each be individually accessible by that identification to provide parameter values to chip registers to configure that chip. The configured chips may be subsequently tested in parallel to evaluate the parameter settings. In addition, the present invention enables chips to share data I/O pins or lines, thereby reducing the quantity of testing machine pins utilized for each chip and enabling a greater quantity of chips to be tested in a parallel fashion.

Method and apparatus for selectively accessing and configuring individual chips of a semi-conductor wafer

Devices and methods that allow floating word lines in memory arrays to be detected are provided. By driving local word lines from each side with divided drive lines, local word lines on one side of the memory array may be set to an predetermined voltage level (e.g., an intermediate voltage level between Vand V). After disconnecting the local word lines on the one side, memory cells on the other side may be tested for read failures, which may indicate floating word lines on the one side.

Test mode for detecting a floating word line

A memory cell signal window testing apparatusand method for testing the signal window of a memory are disclosed. First data is written to a memory cell during a write cycle. A low cell signal is read from the memory cell during a first read cycle. A comparison is made between the low signal and a low reference signal. The result of the comparison is stored in a first storage register. Second data is then written to the memory cell during a write cycle. A high cell signal is read from the memory cell during a second read cycle. A comparison is made between the high cell signal and a high reference signal. The result of the comparison is stored in a second storage register. The results in the first and second storage registers are compared and an output is provided indicating that the memory cell has failed the test if the comparison shows that both the low cell signal is higher than the low reference signal and the high cell signal is lower than the high reference signal.

Memory cell signal window testing apparatus

A method for reducing noise coupling in a memory array is disclosed. The memory array includes a plurality memory cells interconnected by wordlines, bitlines, and platelines. The memory cells are arranged in columns having first and second bitlines coupled to a sense amplifier. During a memory access, at least adjacent bitlines pairs are not activated. The selected bitline pair or pairs are provided with a plateline pulse.

Reducing effects of noise coupling in integrated circuits with memory arrays

A redundancy unit includes first and second fuse blocks for programming the redundancy element. One fuse block has laser blowable fuses and the other electrical fuses. The redundancy unit can be programmed by either one of the fuse blocks, enabling the redundancy unit to able to be used for defects identified before packaging and as well as after.

Hybrid fuses for redundancy

A memory IC having improved sensing during reads is disclosed. The IC includes the use of first and second reference voltages for sensing to compensate for asymmetry that exists between cells on bitline true and bitline complement. The first reference voltage is used for sensing a cell on bitline true while the second reference voltage is used for sensing a cell on bitline complement.

Sensing of memory integrated circuits

An improved redundancy scheme for chained memory architecture is disclosed. The redundancy scheme comprises including redundant cells as part of the memory chain. As such, a redundant cell is used to repair a defective cell within the chain. This eliminates the need in conventional chained architecture to replace the whole memory block when there is a defective cell.

Redundancy in series grouped memory architecture

A memory chain with capacitors having different capacitances, depending on the location of the memory cell within the chain, is described. Varying the capacitances of the capacitors advantageously enables an effective capacitance for all memory cells within the chain to be about the same.

Variable capacitances for memory cells within a cell group

The present invention describes an information recorder which is integrated into an IC, such as ferroelectric RAM device. The recorder counts desired events, such as memory accesses or length of time powered up and stores such information in a latch. The information can be retrieved from the latch to assist in failure analysis and device characterization.

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Apex, NC, United States of America

Norbert Rehm