Micron Technology Incorporated

Kim M Pierce

Kurt D Beigel

Patrick J Mullarkey

Douglas John Cutter

Fan Ho

Brett M Debenham

Dien S Luong

Adrian E Ong

Roland Ochoa

Gregory L Cowan

Todd A Merritt

Jeffrey P Wright

Charles L Ingalls

Michael Amiel Shore

Hua Zheng

Brent Keeth

Troy A Manning

Terry R Lee

Kevin J Ryan

Chris G Martin

Thomas W Voshell

Wallace E Fister

Mike Pearson

Method and apparatus are disclosed for checking the resistance of antifuse elements in an integrated circuit. A voltage based on the resistance of an antifuse element is compared to a voltage based on a known resistance, and an output signal is generated whose binary value indicates whether the resistance of the antifuse element is higher or lower than the known value of resistance. The method and apparatus are useful in verifying the programming of antifuse elements.

Method and apparatus for checking the resistance of programmable elements

A semiconductor integrated circuit and method for compressing test stimuli to one test output signal during a test mode. The test output signal is driven from one input/output node of the semiconductor integrated circuit to a test station through a load board interface. Buffer circuitry on the semiconductor integrated circuit drive a high impedance to the input/output nodes of the integrated circuit during the test mode. The load board interface allows a single test station to receive test output signals from a plurality of semiconductor integrated circuits of the invention during the test mode, thereby allowing one test station to simultaneously test a plurality of circuits.

Semiconductor integrated circuit having compression circuitry for compressing test data, and the test system for utilizing the semiconductor integrated circuit

Semiconductor integrated circuit having compression circuitry for compressing test data, and the test system and method for utilizing the semiconductor integrated circuit

An on-chip test circuit in an integrated circuit memory device includes a test mode terminal and a test data storage circuit having an input coupled to a data terminal of the memory device and an output coupled to a memory-cell array in the memory device. The storage circuit further includes terminals adapted to receive respective read test data and write test data signals. The storage circuit stores bits of data applied on the data terminal when the write test data signal is active. The storage circuit provides on its output the bits of stored data when the read test data signal is active. An error detection circuit includes a first input coupled to the memory-cell array and a second input coupled to the output of the storage circuit. The error detection circuit develops an active error signal on an output when the data on its input is unequal. A test control circuit is coupled to the terminals of the test data storage circuit, and to the test mode terminal. When the test mode signal is active, the test control circuit operates in a first mode to transfer data on the data terminal into the storage circuit, and operates in a second mode to transfer data from the storage circuit to the memory cells in the array. The test control circuit then operates in a third mode to access data stored in the memory cells and in the storage circuit such that the error detection circuit compares the data stored in each addressed memory cell to the data initially transferred to that memory cell.

On-chip circuit and method for testing memory devices

An integrated circuit memory device has a plurality of nonvolatile programmable elements which are used to store a pass/fail status bit at selected milestones in a test sequence. At selected points in the test process an element may be programmed to indicate that the device has passed the tests associated with the selected point in the process. Prior to performing further tests on the device, the element is read to verify that it passed previous tests in the test process. If the appropriate elements are not programmed, the device is rejected. A rejected device may be retested according to the previous test steps. Laser fuses, electrically programmable fuses or antifuses are used to store test results. The use of electrically writeable nonvolatile memory elements allows for programming of the elements after the device has been packaged.

Method and apparatus for storage of test results within an integrated circuit

Method and apparatus are disclosed for reducing antifuse programming time by connecting the programming voltage to the electrode of the antifuse element that has roughened polysilicon.

Method and apparatus for reducing antifuse programming time

Method and apparatus are disclosed for checking the resistance of programmable circuits in an integrated circuit where each programmable circuit includes a programmable element, such as an antifuse. A precharged node is connected to the programmable element and the voltage at the node discharges based on the resistance of the programmable element. An output signal is produced whose binary value is based on the voltage at the node after a sufficient time has elapsed to allow the initial voltage to discharge based on the resistance of the programmable element.

A memory device includes an output data path that transfers data from an I/O circuit coupled to a memory array to an output tri-state buffer. A comparing circuit compares data from the I/O circuit to a desired data pattern. If the data does not match the desired pattern, the comparing circuit outputs an error signal that is input to the output buffer. When the output buffer receives the error signal, the output buffer is disabled and outputs a tri-state condition on a data bus. Since the error signal corresponds to more than one data bit, the tri-state condition of the output buffer is held for more than one tick of the data clock, rather than only a single tick. Consequently, the tri-state condition remains on the bus for sufficiently long that a test system can detect the tri-state condition even at very high clock frequencies.

Method and apparatus for memory array compressed data testing

Semiconductor integrated circuit having compression circuitry for

An antifuse bank includes a bank of self-decoupling anti fuse circuits. The anti fuse circuits are programmed according to a pattern of address bits by blowing antifuses corresponding to bits of the address. The antifuses are blown by applying a high voltage across the antifuse. As each antifuse is blown, its resistance drops and current through the antifuse increases. The self-decoupling circuit detects the increased current flow and, when the anti fuse resistance is sufficiently low, limits current flow through the anti fuse. The antifuse thus does not load the high voltage source as other antifuses are blown.

Self current limiting antifuse circuit

An antifuse bank includes a bank of self-decoupling antifuse circuits. The antifuse circuits are programmed according to a pattern of address bits by blowing antifuses corresponding to bits of the address. The antifuses are blown by applying a high voltage across the antifuse. As each antifuse is blown, its resistance drops and current through the antifuse increases. The self-decoupling circuit detects the increased current flow and, when the antifuse resistance is sufficiently low, limits current flow through the antifuse. The antifuse thus does not load the high voltage source as other antifuses are blown.

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Meridian, ID, United States of America

Kim M Pierce