Abstract: A process is disclosed for forming an integrated circuit device, such as an EPROM device, with a floating gate electrode with a discontinuous phase of metal silicide formed on a surface thereof is described. The process for forming such a discontinuous phase of metal silicide on the surface of a polysilicon floating gate electrode for the device comprises the steps of depositing a first polysilicon layer over a substrate, and preferably over a thin oxide layer on the substrate capable of functioning as a gate oxide; then forming a very thin layer of a silicide-forming metal over the polysilicon layer; and heating the structure sufficiently to cause all of the silicide-forming metal to react with the underlying polysilicon layer to form metal silicide and to coalesce the metal silicide into a discontinuous phase on the surface of the polysilicon layer.

Abstract: A novel semiconductor fabrication chamber includes a quartz vessel and a metal vessel with a resilient sealing member disposed between the quartz and metal vessels to define a vacuum chamber, along with a cooling assembly mounted on a quartz flange extending around the perimeter of the quartz vessel. A liquid or gaseous cooling medium is passed through the cooling assembly to reduce the operating temperature of a portion of the resilient sealing member in contact with the quartz flange during semiconductor fabrication processing so as to extend the useful life of the sealing member. The cooling assembly is secured to the quartz flange using a plurality of clamping fixtures for easy installation and retrofitting.

Abstract: A critical temperature rise .DELTA.R is selected at a value for which electromigration of atoms in the metal conductive line deposited on a semiconductive substrate is predominantly a grain boundary electromigration. Selection of the critical resistance rise is made by performing a number of tests on different ones of a plurality of substantially identical bow tie conductive lines formed of alternating narrow and wide sections interconnected by tapering line sections. Temperatures for the selection of the critical resistance rise are calculated rather than measured so as to more accurately reflect the relatively high local temperature at the site of a void in the metallic conductive line. Plot of a plurality of line widths against temperature for a given current density enables selection of a minimum line width or maximum void depth that will occur in a condition of predominantly grain boundary electromigration and before a large amount of bulk electromigration occurs.

Abstract: In a physical design automation system for producing an optimized cell placement for an integrated circuit chip, a placement optimization methodology is decomposed into a plurality of cell placement optimization processes that are performed simultaneously by parallel processors on input data representing the chip. The results of the optimization processes are recomposed to produce an optimized cell placement. The fitness of the optimized cell placement is analyzed, and the parallel processors are controlled to selectively repeat performing the optimization processes for further optimizing the optimized cell placement if the fitness does not satisfy a predetermined criterion. The system can be applied to initial placement, routing, placement improvement and other problems. The processors can perform the same optimization process on different placements, or on areas of a single placement.

Abstract: A low dielectric constant insulation layer for an integrated circuit structure material, and a method of making same. The low dielectric constant insulation layer comprises a porous insulation layer, preferably sandwiched between non-porous upper and lower insulation layers. The porous insulation layer is formed by depositing a composite layer comprising an insulation material or a material which can be converted to an insulation material, by a converting process and a material which can be converted to a gas upon subjection to the converting process. Release of the gas leaves behind a porous matrix of the insulation material which has a lower dielectric constant than the composite layer.

Abstract: A methodology for generating structural descriptions of complex digital devices from high-level descriptions and specifications is disclosed. The methodology uses a systematic technique to map and enforce consistency of the semantics imbedded in the intent of the original, high-level descriptions. The design activity is essentially a series of transformations operating upon various levels of design representations. At each level, the intended meaning (semantics) and formal software manipulations are captured to derive a more detailed level describing hardware meeting the design goals. Important features of the methodology are: capturing the users concepts, intent, specification, descriptions, constraints and trade-offs; architectural partitioning; what-if analysis at a high level; sizing estimation; timing estimation; architectural trade-off; conceptual design with implementation estimation; and timing closure.

Abstract: An integrated circuit package, as well as a method for fabricating the same, is herein disclosed. The integrated circuit package of the present invention includes a cavity located within an assembly of laminated printed wiring boards. Such cavity provides two or more bonding tiers for connection with a semiconductor die. The contact pads are further connected, through conductive vias, to external connection means such as solder balls or pins. The semiconductor die is encapsulated with a molding compound through a transfer molding process. The present invention is especially advantageous in manufacturing pin grid array ("PGA") and ball grid array ("BGA")integrated circuit packages.

Abstract: An apparatus and method for locating a good approximation of optimal Steiner tree routing in the presence of rectilinear obstacles, including finding a Steiner tree on an escape graph. The escape graph is constructed by forming lines from given points (pins) and obstacles. Obstacles and the segments of obstacles are provided with lines parallel to that segment at a given minimum distance S.sub.min from the obstacle. The lines are constructed until they reach either a boundary of an obstacle or a boundary of the core. For pins which do belong to a boundary of an obstacle, a ray, perpendicular to the segment of the boundary on which the pin is located is constructed from the pin and out from the obstacle until it reaches another obstacle or a boundary of the core. For pins which do not belong to an obstacle, vertical and horizontal lines are constructed. A Steiner tree may then be found on the escape graph by using any number of algorithms such as algorithm S and algorithm M.

Abstract: A CMOS driver circuit which differentially drives a pair of transmission lines at a first terminal in response to a signal on the CMOS driver circuit's input terminal for reception of said signal at a second terminal is provided. The driver circuit has two pairs of drive transistors. Each drive transistor has first and second source/drains and a gate. Each drive transistor pair is connected to one of said transmission line pair, and has a NMOS transistor and a PMOS transistor.

Abstract: An optimized translation lookaside buffer (TLB) utilizes a least-recently-used algorithm for determining the replacement of virtual-to-physical memory translation entries. The TLB is faster and requires less chip area for fabrication. In addition to speed and size, the TLB is also optimized since many characteristics of the TLB may be changed without significantly changing the overall layout of the TLB. A TLB generating program may thus be used as a design aid. The translation lookaside buffer includes a level decoding circuit which allows masking of a variable number of the bits of a virtual address when it is compared to values stored within the TLB. The masking technique may be used for indicating a TLB hit or miss of a virtual address to be translated, and may also be used for invalidating selected entries within the TLB.

Abstract: A substrate includes a non-conductive support layer and a plurality "n" of conductive leads disposed on the support layer. The leads are arranged in a generally radial pattern about a central point on the support layer, each of the leads having a width "w" and spaced a distance "d" from one another at their innermost ends, thereby forming a generally square opening of side dimension "s". The substrate accommodates semiconductor dies ranging in size from smaller than the opening, to approximately equal to that of the opening, to substantially larger than the opening, such as four times the size (linear dimension) of the opening. The die is bonded to the substrate. Other elements of a semiconductor device assembly are added to the resulting structure. Method and apparatus are disclosed.

Abstract: A ring-shaped, substantially planar structure is described for interposing between a chip and a substrate. The ring-shaped structure, being more flexible than a similar solid structure, conforms more readily to any irregularities in the surface of the substrate. Through holes in the planar structure facilitate controlled formation of reflow solder connections between the chip and the substrate. In one embodiment, the ring shape of the planar structure has a gap to facilitate better conformance to irregularities in the surface of the substrate and to minimize "levering" of the chip. Other embodiments provide for "kerfing" of the ring-shaped planar structure to permit even greater flexibility of the structure and less levering of the chip. Angled through holes permit adaptation of mismatched solder bump patterns on the chip and substrate.

Abstract: The present invention provides for a burn-in test which is conducted on the wafer level, before the dies are separated into individual chips and packaged. In a preferred embodiment of the invention, a series of chips are each connected to an external current, ground, and/or alternate signal source(s) for burn-in. Generally, the method herein for a burn-in of a semiconductor die comprises the step of: (a) providing an electrical connection between a die on a semiconductor wafer and an external current source; (b) heating the semiconductor wafer; and (c) applying a common signal across the electrical connection to burn in the die. A preferred method herein provides a semiconductor wafer including a multiplicity of dies and wafer level test points, at least one layer of conductive lines overlying the semiconductor wafer, a means for connecting an individual conductive line to a test point on the wafer; and a means for connecting the conductive lines to an external signal source for exercising the dies.

Abstract: A process monitor for a CMOS integrated circuit includes first and second delay units that are connected in a ring to constitute a ring oscillator that generates pulses having different phases at the outputs of the delay units respectively. The delay units affect the frequency of the pulses and also the rising and falling edges of the pulses differently depending on the process factor of PMOS and NMOS transistors in the delay units. The process factor can be computed from the frequency, or the ratio of the phase differences between the rising and falling edges of the pulses at the outputs of the first and second delay units. The oscillatory configuration of the monitor is highly sensitive to variations in process factor, and enables the monitor to be embodied by a relatively small number of elements that can fit in two input/output slots in a standard integrated circuit layout.

Abstract: Fine, sub-micron line features and patterns are created in a sensitized layer on a semiconductor wafer by a beam of low wavelength radiation, such as X-rays or Gamma-rays. A stream of such radiation is concentrated and collimated by a concentrator, the output of which is disposed in close proximity to the sensitized surface of the wafer. In this manner, the sensitized surface can be converted from one chemical state to another chemical state, essentially point-by-point. By moving one or the other of the beam or the wafer, line features can be converted in the sensitized surface. Typically, non-converted areas of the sensitized surface are removed, for further processing a layer underlying the sensitized surface.

Abstract: An integrated circuit includes a ground plane structure which provides a uniform ground potential throughout the integrated circuit and improves its performance. The ground plane structure is carried atop the active circuit elements of the integrated circuit and connects with each of the ground-potential contact pads of the circuit. A method of making the integrated circuit includes applying a ground plane precursor structure over all of the integrated circuit topology, and removing portions of the precursor structure where the ground plane is not desired. A method of providing bump structures at each of the contact pads for use in TAB bonding of the electrical connections of the integrated circuit to a package structure is also set forth.

Abstract: An apparatus and method for improved clock distribution and control in an integrated circuit which minimizes clock skew between various parts of the integrated circuit chip. Clock loads are evenly distributed between tributaries. Capacitive loading is utilized to balance any differences between tributaries and for minimizing clock skew throughout the integrated circuit.

Abstract: A technique is describe for effecting very-high resolution semiconductor lithography using direct-write afocal electron-beam exposure of a sensitized wafer. A positioning mechanism and needle-like probe similar to those used in scanning-tunneling microscopy are used in conjunction with a controllable electron field emission source to produce a near-field electron beam capable of exposing an electron-beam sensitive resist on a wafer surface. Conventional e-beam resists are used. The technique can be used in conjunction with scanning-tunneling-like operation of the apparatus to record the appearance and nature of the wafer surface, thereby providing information about the location of underlying features. This location information can be used to assist in aligning the exposure patterns to existing structures in the semiconductor wafer.

Abstract: A technique for providing testable core-cell based integrated circuits is described whereby a boundary-scan like technique is employed, but not limited to the external pins (bond pads) of an integrated circuit. An interior boundary-scan path is provided for all peripheral signals of core cells and logic blocks which are not connected to pins of the integrated circuit. This technique provides complete controllability and observability of each core cell and/or logic block on an integrated circuit die, while remaining compatible with test techniques designed into the core cells, and remaining fully compatible with external boundary scan techniques. Method and apparatus are described.

Abstract: An efficient technique for providing ROM memory on a microprocessor local bus is described whereby a ROM and all necessary address decoding and control circuitry is incorporated in a single integrated circuit. By doing this, only one chip is required to add ROM to a microprocessor local bus, saving considerable space and power over discrete implementations. The ROM is implemented in a wide memory format, matching the bus width of the microprocessor to which it is connected. This permits full-speed access to the local bus ROM, and eliminates any need for such techniques as ROM "shadowing".