Abstract: An antifuse structure particularly suitable for field programmable gate arrays is presented. In most present day processes the antifuse structure is formed with a refractory metal layer, amorphous silicon layer and refractory metal layer sandwiched between two metal interconnection lines. Unprogrammed resistances of very high values, programmed resistances of very low values, short programming times and desirable programming voltages are among the advantages realized.

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: The present invention provides for an embedded test circuit in an integrated circuit. The integrated circuit has a plurality of conducting line segments and fuse elements therebetween with each fuse element selectively connectable in series through the crossing line segments and programming circuits between a pair of programming terminals. Each fuse element is also associated with a pair of test lines with each test line connected to one of the line segments having the fuse element between the test lines. Each test line pair is selectively connectable to a pair of test terminals. The resistance of a selected fuse element is measured by selectively passing a current between the first and second programming terminals through the selected fuse element and selectively measuring a voltage drop across the selected fuse element through the pair of test terminals.

Abstract: The invention provides a packaging technique implementing an electronic circuit, comprising several individually packaged sub-circuits, on a circuit board within the footprint of a single package. The embodiment of the present invention is particularly advantageous when implementing application specific integrated circuits (ASICs) or field programmable gate arrays (FPGAs). Selected pins of an upper package are electrically coupled to corresponding pins of the next lower adjacent package such that the pins of the uppermost package can be coupled to the pins of the lowermost package and correspondingly to the signal leads and power bus conductors of the printed circuit board. Portions of selected pins may be removed from one or more packages prior to forming the stacked structure to electrically isolate corresponding pins of upper packages from the pins of lower packages. A template is provided that permits rapid identification of pins to be removed before the packages are configured in the stack.

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. The method comprises forming a first metal interconnection layer on the first insulating layer; forming a programming layer on the first metal interconnection line; forming a relatively thin, second insulating layer over the programming layer; forming a first aperture through the second insulating layer where the antifuse is to be located to expose a portion of the programming layer; forming a barrier metal layer on the second insulating layer and in said first aperture to contact the portion of said programming layer; forming a relatively thick, third insulating layer on the barrier metal layer; forming a second aperture to expose a portion of the barrier metal layer; and forming a second metal interconnection layer on the third insulating layer and in the second aperture to contact the portion of the second barrier metal layer.

Abstract: A FPGA matching the organization and performance of mask programmable gate arrays is presented. The core array is organized into rows of continuous series transistors (CSTs) and rows of small latch/logic blocks. The source/drains and gate of each of the transistors are connected to line segments. The input and output terminals of the blocks are also connected to line segments. Programmable antifuses are located at the intersections of the line segments, which also include others for power and routing purposes. The FPGA can be efficiently configured into a user's application with the flexibility of the CSTs and the efficiency of the latch/logic blocks, which may also be configured into RAM arrays.

Abstract: An antifuse structure particularly suitable for field programmable gate arrays is presented. In most present day processes the antifuse structure is formed with a refractory metal layer, amorphous silicon layer and refractory metal layer sandwiched between two metal interconnection lines. Unprogrammed resistances of very high values, programmed resistances of very low values, short programming times and desirable programming voltages are among the advantages realized.

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: A voltage regulator especially adaptable for use with field-programmable gate arrays (FPGA). The voltage regulator is configurable as a true voltage regulator or, alternatively, as a pseudo-voltage regulator. The voltage regulator includes circuitry to rapidly generate an operating voltage for the core or nucleus logic elements. Additional circuitry is provided to reduce the steady-state power consumption once the operating voltage is reached. To compensate for die-to-die variations, additional circuitry is also provided to adjust the compensation delays or switching rates.

Abstract: An antifuse in an integrated circuit which has first and second conducting lines, a semiconductor layer of amorphous silicon between the first and second conducting lines, and a barrier metal layer of TiN between the semiconductor layer and the first conducting layer is disclosed. The TiN layer is nonstoichiometric composition to enhance the probability of said antifuse having a desired resistance when said antifuse is programmed. More specifically, the TiN layer has a composition of Ti.sub.1.0 N.sub.0.5-0.8.

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 FPGA matching the organization and performance of mask programmable gate arrays is presented. The core array is organized into rows of continuous series transistors (CSTs) and rows of small latch/logic blocks. The source/drains and gate of each of the transistors are connected to line segments. The input and output terminals of the blocks are also connected to line segments. Programmable antifuses are located at the intersections of the line segments, which also include others for power and routing purposes. The FPGA can be efficiently configured into a user's application with the flexibility of the CSTs and the efficiency of the latch/logic blocks, which may also be configured into RAM arrays.

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 first storing means for storing a signal from the first storing means, and a second multiplexer connected to an output terminal of the latch.