Micron Technology Incorporated

Daryl L Habersetzer

James E Miller, Jr

Manny K Ma

Gordon D Roberts

Jeffrey D Bruce

Eric T Stubbs

Kurt D Beigel

Casey R Kurth

Patrick J Mullarkey

Jason E Graalum

Douglas John Cutter

Scott James Derner

Kurt D Biegel

Circuitry for programming antifuse elements is provided which permits all antifuse elements in a bank to be programmed simultaneously, thereby enhancing the speed at which antifuse elements may be programmed. In one embodiment, a feedback circuit is associated with each antifuse element to stop the flow of current through the antifuse element once it is programmed. In another embodiment, circuitry is provided for generating a separate programming pulse for each antifuse element, which is selected for programming.

Circuit for programming antifuse bits

As part of a memory array, a circuit is provided for altering the drive applied to an access transistor that regulates electrical communication within the memory array. In one embodiment, the circuit is used to alter the drive applied to a sense amp's voltage-pulling transistor, thereby allowing modification of the voltage-pulling rate for components of the sense amp. A sample of test data is written to the memory array and read several times at varying drive rates in order to determine the sense amp's ability to accommodate external circuitry. In another embodiment, the circuit is used to alter the drive applied to a bleeder device that regulates communication between the digit lines of the memory array and its cell plate. Slowing said communication allows defects within the memory array to have a more pronounced effect and hence increases the chances of finding such defects during testing. The circuit is configured to accept and apply a plurality of voltages, either through a contact pad or from a series of discrete voltage sources coupled to the circuit.

Method of preparing to test a capacitor

A memory device includes an address selection circuit to store addresses of selected rows of memory cells. During a refresh mode, only the memory cells of the selected rows are refreshed. The addresses of the selected rows can be stored automatically by the memory device during a memory operation mode or manually by a user during a programming mode.

Partial array self-refresh

A method of verifying whether unprogrammed antifuses are leaky in a semiconductor memory. The method involves the steps of: connecting the antifuse in series with a node; providing current to the node, the current being sufficient to charge the node from a first to a second voltage; detecting whether the voltage at the node charges to the second voltage, or remains at the first voltage to indicate that the antifuse is leaky; outputting signals indicating the result of the detection; and detecting the voltage at the node remains at the first voltage indicates that the antifuse is leaky. In another embodiment, a method of verifying whether antifuses have been programmed properly in a semiconductor memory. The method includes the steps of: connecting the antifuse in series with a node; providing current to the node through a parallel combination of a first transistor and a second transistor that is sufficient to charge the node from a first voltage to a second voltage; and detecting whether the voltage at the node charges to the second voltage or remains at the first voltage to indicate that the antifuse is programmed properly; outputting first and second signals indicating the result of the detection; and detecting the voltage at the node remains at the first voltage indicates that the antifuse is programmed properly.

Circuit and method for voltage regulation in a semiconductor device

A memory device includes an address selection circuit to store addresses of selected rows of memory cells. During a refresh mode, only the memory cells of the selected rows are refreshed. The addresses of the selected rows can be stored by a user or automatically.

A test-mode latching circuit residing on an integrated circuit with test circuitry and operational circuitry has an enable state and a disable state. In the enable state, a test key is able to be latched so as to trigger a test mode. In the disable state, test key inputs are not latched, and thus, test modes are not entered. Initially, the circuit is readily enabled so that the IC can be tested upon fabrication. The circuit is locked in a disable state before external sale. A re-enable circuit is present to preclude inadvertent switching of the latching circuit back into the enable state during customer operation. Safeguards are implemented to avoid inadvertently re-enabling the latching circuit. To re-enable the latching circuit, an out-of-spec voltage is applied to an anti-fuse capacitor or programmable logic circuit while an out-of-spec voltage of the same or another signal is detected at a field device. In one embodiment, the state switches to the enable state in response to the out-of-spec voltage. In alternative embodiments, an additional or subsequent signal, such as a prescribed clock pattern, occurs before the first circuit switches to the enable state.

Method for disabling and re-enabling access to IC test functions

Method of compensating for a defect within a semiconductor device

Apparatus for disabling and re-enabling access to IC test functions

A test-mode latching circuit residing on an integrated circuit with test circuitry and operational circuitry has an enable state and a disable state. In the enable state, a test key is able to be latched so as to trigger a test mode. In the disable state, test key inputs are not latched and, thus, test modes are not entered. Initially, the circuit is readily enabled so that the IC can be tested upon fabrication. The circuit is locked in a disable state before external sale. A re-enable circuit is present to preclude inadvertent switching of the latching circuit back into the enable state during customer operation. Safeguards are implemented to avoid inadvertently re-enabling the latching circuit. To re-enable the latching circuit, an out-of-spec voltage is applied to an anti-fuse capacitor or programmable logic circuit while an out-of-spec voltage of the same or another signal is detected at a field device. In one embodiment, the state switches to the enable state in response to the out-of-spec voltage. In alternative embodiments, an additional or subsequent signal, such as a prescribed clock pattern, occurs before the first circuit switches to the enable state.

Driver circuit for a voltage-pulling device

A method of verifying whether unprogrammed antifuses are leaky in a semiconductor memory. The method involves the steps of: connecting the antifuse in series with a node; providing current to the node, the current being sufficient to charge the node from a first to a second voltage; detecting whether the voltage at the node charges to the second voltage, or remains at the first voltage to indicate that the antifuse is leaky; outputting signals indicating the result of the detection; and detecting the voltage at the node remains at the first voltage indicates that the antifuse is leaky. In another embodiment, a method of verifying whether antifuses have been programmed properly in a semiconductor memory. The method includes the steps of: connecting the antifuse in series with a node; providing current to the node through a parallel combination of a first transistor and a second transistor that is sufficient to charge the node from a first voltage to a second voltage; and detecting whether the voltage at the node charges to the second voltage or remain at the first voltage to indicate that the antifuse is programmed properly; outputting first and second signals indicating the result of the detection; and detecting the voltage at the node remains at the first voltage indicates that the antifuse is programmed properly.

Growing community of inventors

Boise, ID, United States of America

Daryl L Habersetzer