Abstract: A combination of a current limiting resistor and a clamping Schottky diode prevent substantial forward biasing of a pn junction associated with a pad in a snapback device during normal operation, but do not substantially affect triggering of the device during an unbiased electrostatic discharge event.

Abstract: A number of antifuse support circuits and methods for operating them are disclosed according to embodiments of the present invention. An external pin is coupled to a common bus line in an integrated circuit to deliver an elevated voltage to program antifuses in a programming mode. An antifuse having a first terminal coupled to the common bus line is selected to be programmed by a control transistor in a program driver circuit coupled to a second terminal of the antifuse. The program driver circuit has a high-voltage transistor with a diode coupled to its gate to bear a portion of the elevated voltage after the antifuse has been programmed. The program driver circuit also has an impedance transistor between the high-voltage transistor and the control transistor to reduce leakage current and the possibility of a snap-back condition in the control transistor. A read circuit includes a transistor coupled between a read voltage source and the second terminal to read the antifuse in an active mode.

Abstract: According to embodiments of the present invention, circuits have elements to protect a high-voltage transistor in a gate dielectric antifuse circuit. An antifuse has a layer of gate dielectric between a first terminal coupled to receive an elevated voltage and a second terminal, and a high-voltage transistor is coupled to the antifuse and has a gate terminal. An intermediate voltage between the supply voltage and the elevated voltage is coupled to the gate terminal of the high-voltage transistor to protect the high-voltage transistor.

Abstract: According to embodiments of the present invention, an antifuse circuit is operated by coupling an elevated voltage to a first terminal of an antifuse, controlling current in the antifuse with a program driver circuit coupled to a second terminal of the antifuse, and shunting current around the antifuse with a bypass circuit coupled between the first terminal of the antifuse and the program driver circuit to protect the antifuse. The antifuse includes a layer of gate dielectric between the first terminal and the second terminal. The embodiments of the present invention protect a gate dielectric antifuse.

Abstract: A fuse for use in a semiconductor device includes spaced-apart terminals with at least two layers of conductive material and a single-layer conductive link joining the spaced-apart terminals and including a single layer of conductive material. A first, lower layer of the terminals of each fuse may be formed from conductively doped polysilicon. The second, upper layer of each fuse terminal may be formed from a polycide, a metal silicide, a metal, or a conductive alloy. The conductive link of each fuse may be formed from either the material of the first layer or the material of the second layer. Methods for fabricating the fuse include forming the first and second layers and patterning the first and second layers so as to form a fuse with the desired structure.

Abstract: A large-scale substrate carries semiconductor devices and at least one pair of common conductive regions in communication therewith. Each common conductive region is configured to be electrically connected with both a force contact and a sense contact of burn-in stressing equipment. Such equipment includes at least one pair of force contacts for applying a force voltage across a pair of common conductive regions and, thus, across the large-scale substrate. A corresponding pair of sense contacts facilitates monitoring of a voltage applied across each of the semiconductor devices by the force contacts. Methods and systems for evaluating a voltage that has been applied to two or more semiconductor devices by way of a single pair of force contacts are also disclosed, as are methods and systems for, in response to a measured voltage, modifying the force voltage so that a desired voltage may be applied across each of the semiconductor devices.

Abstract: A method, circuit and system for determining burn-in reliability from wafer level burn-in. The method according to the present invention includes recording the number of failures in each IC die in nonvolatile elements on-chip at points in time over the duration of wafer level burn-in testing. The number of failures in each IC die, along with their associated points in time, may be used to create burn-in reliability curves which are conventionally derived using other processes that may be less cost effective or not possible to effect with unpackaged IC dice. Circuits and systems associated with the method of the present invention are also disclosed.

Abstract: A metal silicide fuse for a semiconductor device. The fuse includes a conductive region positioned adjacent a common well of a first conductivity type, a terminal region positioned adjacent a well of a second conductivity type, and a narrowed region located between the terminal region and the conductive region and positioned adjacent a boundary between the two wells. Upon applying at least a programming current to the fuse, the fuse “blows” at the narrowed region. The diode or diodes between wells of different conductivity types wells and the Schottky diode or diodes between the remaining portions of the fuse and wells adjacent thereto control the flow of current through the remainder of the fuse and through the associated wells of the semiconductor device. When the fuse has been “blown,” the diodes and Schottky diodes prevent current of a normal operating voltage from flowing through the wells of the semiconductor device.

Abstract: A number of antifuse support circuits and methods for operating them are disclosed according to embodiments of the present invention. An external pin is coupled to a common bus line in an integrated circuit to deliver an elevated voltage to program antifuses in a programming mode. An antifuse having a first terminal coupled to the common bus line is selected to be programmed by a control transistor in a program driver circuit coupled to a second terminal of the antifuse. The program driver circuit has a high-voltage transistor with a diode coupled to its gate to bear a portion of the elevated voltage after the antifuse has been programmed. The program driver circuit also has an impedance transistor between the high-voltage transistor and the control transistor to reduce leakage current and the possibility of a snap-back condition in the control transistor. A read circuit includes a transistor coupled between a read voltage source and the second terminal to read the antifuse in an active mode.

Abstract: Systems and methods are provided for a temperature-compensated threshold voltage VT. The stability problems associated with temperature changes are reduced for LL4TCMOS SRAM cells by providing a temperature-compensated VTN. According to one embodiment, a temperature-based modulation of a VBB potential back-biases a triple-well transistor with a temperature-compensated voltage to provide the pull-down transistor with a temperature-compensated VTN that is flat or relatively flat with respect to temperature. One embodiment provides a bias generator, including a charge pump coupled to a body terminal of the transistor(s), and a comparator coupled to the charge pump. The comparator includes a first input that receives a reference voltage, a second input that receives a VT-dependent voltage, and an output that presents a control signal to the charge pump and causes the charge pump to selectively charge the body terminal of the transistor to compensate for temperature changes.

Abstract: Systems and methods are provided for regulating a memory circuit. The memory circuit regulation system includes an array regulator adapted for distributing an array supply voltage to a memory cell array, and at least one periphery regulator adapted for distributing at least one periphery supply voltage to at least one periphery circuit. In one embodiment, the array supply voltage is higher than the at least one periphery supply voltage to account for the fundamental lower limit of voltage operation for the LL4TCMOS SRAM cells. The higher array supply voltage provides appropriate stability margins for the SRAM cells so as to discourage or prevent accidental writes to the cells. In another embodiment, the array regulator sources a temperature-dependent current to provide an offset to the temperature-dependent subthreshold leakage current in the plurality of LL4TCMOS SRAM cells.

Abstract: A metal silicide fuse for a semiconductor device. The fuse includes a conductive region positioned adjacent a common well of a first conductivity type, a terminal region positioned adjacent a well of a second conductivity type, and a narrowed region located between the terminal region and the conductive region and positioned adjacent a boundary between the two wells. Upon applying at least a programming current to the fuse, the fuse “blows” at the narrowed region. The diode or diodes between wells of different conductivity types wells and the Schottky diode or diodes between the remaining portions of the fuse and wells adjacent thereto control the flow of current through the remainder of the fuse and through the associated wells of the semiconductor device. When the fuse has been “blown,” the diodes and Schottky diodes prevent current of a normal operating voltage from flowing through the wells of the semiconductor device.

Abstract: A metal silicide fuse for a semiconductor device. The fuse includes a conductive region positioned adjacent a common well of a first conductivity type, a terminal region positioned adjacent a well of a second conductivity type, and a narrowed region located between the terminal region and the conductive region and positioned adjacent a boundary between the two wells. Upon applying at least a programming current to the fuse, the fuse “blows” at the narrowed region. The diode or diodes between wells of different conductivity types wells and the Schottky diode or diodes between the remaining portions of the fuse and wells adjacent thereto control the flow of current through the remainder of the fuse and through the associated wells of the semiconductor device. When the fuse has been “blown,” the diodes and Schottky diodes prevent current of a normal operating voltage from flowing through the wells of the semiconductor device.

Abstract: Systems and methods are provided for regulating a memory circuit. The memory circuit regulation system includes an array regulator adapted for distributing an array supply voltage to a memory cell array, and at least one periphery regulator adapted for distributing at least one periphery supply voltage to at least one periphery circuit. In one embodiment, the array supply voltage is higher than the at least one periphery supply voltage to account for the fundamental lower limit of voltage operation for the LL4TCMOS SRAM cells. The higher array supply voltage provides appropriate stability margins for the SRAM cells so as to discourage or prevent accidental writes to the cells. In another embodiment, the array regulator sources a temperature-dependent current to provide an offset to the temperature-dependent subthreshold leakage current in the plurality of LL4TCMOS SRAM cells.

Abstract: Systems and methods are provided for a temperature-compensated threshold voltage VT. The stability problems associated with temperature changes are reduced for LL4TCMOS SRAM cells by providing a temperature-compensated VTN. According to one embodiment, a temperature-based modulation of a VBB potential back-biases a triple-well transistor with a temperature-compensated voltage to provide the pull-down transistor with a temperature-compensated VTN that is flat or relatively flat with respect to temperature. One embodiment provides a bias generator, including a charge pump coupled to a body terminal of the transistor(s), and a comparator coupled to the charge pump. The comparator includes a first input that receives a reference voltage, a second input that receives a VT-dependent voltage, and an output that presents a control signal to the charge pump and causes the charge pump to selectively charge the body terminal of the transistor to compensate for temperature changes.

Abstract: Systems and methods are provided for a temperature-compensated threshold voltage VT. The stability problems associated with temperature changes are reduced for LL4TCMOS SRAM cells by providing a temperature-compensated VTN. According to one embodiment, a temperature-based modulation of a VBB potential back-biases a triple-well transistor with a temperature-compensated voltage to provide the pull-down transistor with a temperature-compensated VTN that is flat or relatively flat with respect to temperature. One embodiment provides a bias generator, including a charge pump coupled to a body terminal of the transistor(s), and a comparator coupled to the charge pump. The comparator includes a first input that receives a reference voltage, a second input that receives a VT-dependent voltage, and an output that presents a control signal to the charge pump and causes the charge pump to selectively charge the body terminal of the transistor to compensate for temperature changes.

Abstract: An integrated circuit anti-fuse is described which is fabricated as a capacitor using a layer of oxide. The two plates of the anti-fuse are coupled to appropriate voltage levels to rupture the oxide and form a conductive short between the plates. One of the plates is formed as a diffused well which is coupled to an external voltage during programming. The well is biased to an internal voltage during normal operation of the circuit incorporating the anti-fuse.

Abstract: An electrostatic discharge (ESD) protection device is provided. The ESD protection device includes a substrate, a first and a second doped region formed in the substrate. The first and second doped regions are separated from each other by only the substrate region. The ESD protection device includes no gate above the first and second doped regions. Furthermore, the distance separating the first and second doped regions is defined by a length of a resist during a process of forming the ESD protection device.

Abstract: A metal silicide fuse for a semiconductor device. The fuse includes a conductive region positioned adjacent a common well of a first conductivity type, a terminal region positioned adjacent a well of a second conductivity type, and a narrowed region located between the terminal region and the conductive region and positioned adjacent a boundary between the two wells. Upon applying at least a programming current to the fuse, the fuse “blows” at the narrowed region. The diode or diodes between wells of different conductivity types wells and the Schottky diode or diodes between the remaining portions of the fuse and wells adjacent thereto control the flow of current through the remainder of the fuse and through the associated wells of the semiconductor device. When the fuse has been “blown,” the diodes and Schottky diodes prevent current of a normal operating voltage from flowing through the wells of the semiconductor device.

Abstract: An adjustable setpoint ESD core clamp for ESD protection circuits is disclosed. The core clamp includes an SCR whose P+N trigger junction is referenced to a diode stack. The SCR is non-avalanche triggered into a low impedance state at a set value of Vcc, as determined by the diode stack, which allows the ESD device to turn on at a lower voltage, thereby protecting internal circuitry.