Abstract: A field programmable gate array integrated circuit which has numerous features for testing prior to programming the antifuses in the integrated circuit is provided. The circuits used to program the antifuses are also used for much of the preprogramming testing. The functionality of continuous series transistors and latch logic blocks may be tested together with the continuity of their programmable connections. Programmable input/output buffer circuits and clock circuits which set the desired clock network paths may be tested with signals on a serial scan path which passes through the input/output buffer circuits and clock circuits. Process characterization tests without the requirement of high-speed test equipment are also provided.

Abstract: An FPGA includes primary resources and redundant resources. To program an FPGA to perform a desired function, a pattern of programmable elements to be programmed that takes advantage of primary resources only is first prepared. This pattern is then modified responsive to previously obtained information about defects within the FPGA. The modified pattern takes advantage of redundant resources as direct or indirect substitutes for FPGA elements rendered unusable by defects. The FPGA is programmed in accordance with the modified pattern.

Abstract: The present invention provides a voltage regulator especially adaptable for use with a field-programmable gate array (FPGA). The voltage regulator of the present invention rapidly generates an operating voltage for the core or nucleus logic elements upon application of external power while preventing degradation of the fuses. The core or regulated voltage of a FPGA can be set to a level that provides maximum performance with minimum power consumption or, alternatively, permits propagation delays and switching rates to be adjusted so as to compensate for die to die variation. Since it is common for electrical parameters of FPGA manufactured in different wafer fabrication facilities to vary, the voltage regulator is configurable as a true voltage regulator or, alternatively, as a pseudo-voltage regulator. The voltage regulator comprises an operational transconductance amplifier with a single gain stage followed by an NMOS source follower.

Abstract: The present invention provides for an antifuse in an integrated circuit, which has a stacked antifuse structure on a first interconnection line. The stacked structure has a first programming layer of amorphous silicon on the first interconnection line, a very thin insulating layer of silicon dioxide on the first programming layer, and a second programming layer of amorphous silicon on the very thin oxide layer. A second interconnection line on the second programming layer completes the antifuse which has a low leakage current between the first and second interconnection lines.

Abstract: An integrated circuit having system logic with programmable elements, decoding logic coupled to the programmable elements for addressing the programmable elements and a plurality of input/output buffer circuits for passing signals between the system logic and the exterior of the integrated circuit through input/output terminals is disclosed. Each input/output buffer circuit comprises an output driver stage having an output terminal connected to an input/output terminal; and a plurality of cells, each cell having a multiplexer, a flip-flop connected to an output terminal of the first multiplexer for storing a signal from the first multiplexer, a latch connected to an output terminal of the flip-flop for storing a signal from the flip-flop, and a second multiplexer connected to an output terminal of the latch.

Abstract: Various improvements in the fabrication of an antifuse having silicon-amorphous silicon-metal layer structure are presented. Included are improved deposition techniques for the amorphous silicon layer. The improvements include steps for the fabrication of such an antifuse without the use of platinum and the resulting antifuse and contact structures.

Abstract: The present invention provides for a method of forming an antifuse in an integrated circuit having a first insulating layer on a semiconductor substrate.

Abstract: An improved RAM-logic tile (RLT) for use in a field programmable gate array (FPGA) is presented. The RLTs are located at the intersection of global horizontal and vertical lines. Wiring segments run locally between RLTs and contain programmable antifuses for connecting segments within an RLT and to neighboring RLTs. The RLTs are implemented with transmission gates and can be efficiently configured into a memory structure and/or logic device.

Abstract: An antifuse structure in an integrated circuit including a first interconnection line, a second interconnection line formed over the first interconnection line, and a plurality of programming layers between the first and second interconnection lines. Each pair of programming layers has a metal layer therebetween which dissolves with the programming layers to form a conducting link during the programming of such antifuse structure. Such antifuse structure may also include a conductive plug between the programming layers and the second interconnection line.

Abstract: A field programmable gate array integrated circuit which has numerous features for testing prior to programming the antifuses in the integrated circuit is provided. The circuits used to program the antifuses are also used for much of the preprogramming testing. The functionality of continuous series transistors and latch logic blocks may be tested together with the continuity of their programmable connections. Programmable input/output buffer circuits and clock circuits which set the desired clock network paths may be tested with signals on a serial scan path which passes through the input/output buffer circuits and clock circuits. Process characterization tests without the requirement of high-speed test equipment are also provided.

Abstract: The present invention provides for an integrated circuit antifuse structure having a first metal interconnection line, a programing layer over the first interconnection line, an etch stop layer over the programming layer, a sacrificial buffer layer over the etch stop layer, an insulating layer over the buffer layer, and a second metal interconnection line over the insulating layer. An aperture extends through the insulating layer and the buffer layer. The buffer layer has etching characteristics which are different from those of the insulating layer and the etch stop layer. This permits the aperture through the insulating layer to be formed with substantially vertical sides and through the buffer layer to be formed with substantially sloped sides. The second interconnection line extends into the aperture to form an antifuse structure with a low capacitance and a consistent programming voltage.

Abstract: A method and resulting antifuse structure in an integrated circuit include a first metal interconnection layer on a first insulating layer over the substrate of the integrated circuit, a second insulating layer over the first metal interconnection layer. The second insulating layer has a via therein and a programming layer is located in the via. Such programming layer includes a first region on the first metal interconnection layer which is removed from sides of the second insulating layer in the via, and a second region on the sides of the second insulating layer via. The first region has substantially a first thickness, the second region has substantially a second thickness which is greater than the first thickness. Upon programming the antifuse structure, a conducting link forms in the first region of the programming layer.

Abstract: A bandgap generator including an MOS current mirror, first and second bipolar transistors and an MOS transistor pair operating in saturation. Cascode transistors interconnect the saturation transistor pair and the MOS transistor pair. A bias resistor interconnects the one of the cascode transistors and one transistor of the MOS current mirror.

Abstract: An integrated circuit having system logic with programmable elements, decoding logic coupled to the programmable elements for addressing the programmable elements and a plurality of input/output buffer circuits for passing signals between the system logic and the exterior of the integrated circuit through input/output terminals is disclosed. Each input/output buffer circuit comprises an output driver stage having an output terminal connected to an input/output terminal; and a plurality of cells, each cell having a multiplexer, a flip-flop connected to an output terminal of the first multiplexer for storing a signal from the first multiplexer, a latch connected to an output terminal of the flip-flop for storing a signal from the flip-flop, and a second multiplexer connected to an output terminal of the latch.

Abstract: Various improvements in the fabrication of an antifuse having silicon-amorphous silicon-metal layer structure are presented. Included are improved deposition techniques for the amorphous silicon layer. The improvements include steps for the fabrication of such an antifuse without the use of platinum and the resulting antifuse and contact structures.

Abstract: A method of forming an antifuse in an integrated circuit having an insulating layer on a semiconductor substrate is provided. The method comprises forming a first metal interconnection layer on the insulating layer; forming a first barrier metal layer on the first metal interconnection layer; forming an amorphous silicon layer on the first barrier metal layer; forming another barrier metal layer atop the amorphous silicon layer; and forming a second metal interconnection layer on the second barrier metal layer. In at least one of the barrier metal forming steps, the barrier metal is formed by sputtering a barrier metal target which includes a semiconductor dopant, such as dopant.

Abstract: An antifuse structure in an integrated circuit is provided. The antifuse structure has a first metal interconnection line and a first insulating layer over the first metal interconnection line. The first insulating layer has a via exposing a top surface of the first metal interconnection line. In the first aperture a metal plug contacts the first metal interconnection layer and has a top surface substantially coplanar with a top surface of the first insulating layer. A metal pad contacts and covers the top surface of the metal plug. The metal pad should be formed by a viscous barrier metal, such as TiW, to smooth the surface of the metal plug. A second insulating layer, relatively thin with respect to said first insulating layer, covers the metal pad and has an aperture exposing a top surface of the metal pad. A programming layer deposited over the second insulating layer and into the aperture contacts the top surface of metal pad. A second metal interconnection line rests on the programming layer.

Abstract: An antifuse structure in an integrated circuit including a first interconnection line, a second interconnection line formed over the first interconnection line, and a plurality of programming layers between the first and second interconnection lines. Each pair of programming layers has a metal layer therebetween which dissolves with the programming layers to form a conducting link during the programming of such antifuse structure. Such antifuse structure may also include a conductive plug between the programming layers and the second interconnection line.

Abstract: A voltage regulator especially adaptable for use with field-programmable gate arrays (FPGAs). The voltage regulator includes a frequency compensated differential amplifier, a configurable feedback network for setting the gain of the voltage regulator, and a plurality of source follower devices for driving the feedback network and providing a regulated supply voltage. A bandgap generator may also be provided for generating a reference bias voltage that is independent of temperature.

Abstract: A method and structure for an improved antifuse in an integrated circuit having a sacrificial layer under a programming layer which forces a conductive link upon programming to be formed away from corner regions of the via structures. The method includes the unique step of forming an improved aperture or via with sides through an inter dielectric layer where the antifuse is to be located. The improved aperture or via exposes a portion of a metal interconnection line through a portion of sacrificial layer located away from the inter dielectric layer sides. Such improved method of forming the antifuse also provides a superior antifuse structure.