Abstract: A molded semiconductor device (24) having greater resistance to package cracking during board mounting in addition to increased thermal performance is provided wherein the device has a reduced semiconductor die to flag interface and a drop-in heat sink. The semiconductor die (12) is mounted on a leadframe (16) having a flag (15) with an opening to expose a substantial portion of the inactive surface (14) of the die (12). Decreasing the interfacial contact area between the die (12) and the flag (15) reduces the risk of package cracking during board mounting by limiting the area where delamination typically occurs. An encapsulant (22) forms a package body which encompasses an opening (23) to expose a substantial portion of the inactive surface (14) of the semiconductor die (12). A heat sink (26) is inserted into the opening (23), directly coupling the heat sink (26) to the die (12), after the semiconductor package is mounted onto a printed circuit board.
Abstract: A semiconductor-mounting heat-sink base for use with a plastic package or flexible printed wiring board which eliminates the possibility of semiconductor or package reliability being adversely affected due to a difference in thermal expansion coefficient between the heat sink base and the semiconductor or plastic package. The heat-sink base has a semiconductor-mounting portion comprising a Cu--W or Cu--Mo composite alloy containing 5 to 25 wt. % of copper made by an infiltration process, and a portion adjacent to a plastic package which comprises a copper or copper alloy containing not less than 95% of copper.
Abstract: A two-step analog-to-digital converter and BiCMOS fabrication method. The fabrication method provides pseudosubstrate isolation of digital CMOS devices from the analog devices. The converter uses NPN current switching in a flash analog-to-digital converter and in a digital-to-analog converter for low noise operation. CMOS digital error correction and BiCMOS output drivers provide high packing density plus large output load handling. Timing control aggregates switching events and puts them into intervals when noise sensitive operations are inactive. The fabrication method uses a thin epitaxial layer with limited thermal processing to provide NPN and PNP devices with large breakdown and Early voltages. Laser trimmed resistors provide small long term drift due to dopant stabilization in underlying BPSG and low hydrogen nitride passivation.
February 21, 1995
Date of Patent:
January 2, 1996
Glenn A. DeJong, Kantilal Bacrania, Michael D. Church, Gregory J. Fisher, John T. Gasner, Akira Ito, Jeffrey M. Johnston, Dave Kutchmarick, Choong-Sun Rhee
Abstract: A bipolar integrated circuit with N-type wells (2) formed in a P-type substrate (1) includes in first wells, first transistors (EBC), the well of which constitutes the collector. P-type base region (7a) is formed in the first well with an N+ emitter region (8) formed in the base region. In at least a second well forming a collector, a composite second transistor (E'B'C') is constituted by an elemental third transistor (E.sub.1 B.sub.1 C') comprising regions of the same doping level as the first transistor and an elemental fourth transistor (E.sub.2 B.sub.2 C') having a base region (11) with a high doping level with respect to that of the bases of the first transistor. Emitter regions (8b, 12) of the elemental transistors are of the same doping level as that of the first transistors. The emitters and bases of the third and fourth elementary transistors are interconnected and constitute the emitter and the base of the composite second transistor.
Abstract: An SOI/DI IC chip including a handle wafer in the form of a section of silicon substrate contiguous with the layer of insulation beneath the silicon slice containing the device regions separated by trenches filled with low-conductivity polysilicon dielectric. One of the trenches is etched through the layer of insulation, and the polysilicon in that trench is doped to provide desired electrical conductivity to establish electrical contact with the handle wafer. Metallization is applied over the top of this one trench to make possible electrical connection to the handle wafer from above the chip by use of conventional wiring techniques.
Abstract: The present invention provides a sub-mount type device for emitting light which has high speed response and yet can radiate heat sufficiently. The sub-mount type device for emitting light comprises a heat sink (4), a sub-mount body (62) mounted on the heat sink (4) which comprises an insulating layer (38) with a upper face and a lower face, a upper electrode (42) on the upper face and a lower electrode 44 and 36 on the lower face, the insulating layer having two parts of the insulating layer (38) thickness of which is different, and a chip (30) for emitting light above the thinner part (39) of the insulating layer (38).
Abstract: A modification of the self-aligned double poly fabrication process for bipolar transistors employs a thin sacrificial dielectric film to protect the wafer surface during the etching of an emitter opening through an overlying polysilicon contact layer. The sacrificial layer, which is preferably silicon dioxide for a silicon wafer, is thick enough to serve as an etch stop but thin enough to permit dopant from the polysilicon contact to be driven-in through the film to form an extrinsic base region. The dielectric film is left in place under the base contact polysilicon, but removed from the emitter area. It is preferably about 10-20 Angstroms thick when implemented as a silicon dioxide film. With this material system, the extrinsic base drive-in is preferably performed either by a rapid isothermal anneal at about 1,000.degree. C. for about 30-40 seconds, or in a furnace at about 975.degree. C. for about 10 minutes.
Abstract: A semiconductor device includes at least a first semiconductor chip and a second semiconductor chip each having a first surface and a second surface. The second surface of the first semiconductor chip confronts the first surface of the second semiconductor chip. Additionally, the semiconductor device includes a plurality of leads having inner portions and outer portions, where the inner portions of the leads are electrically coupled to selected portions on one of the first and second surfaces of each of the first and second semiconductor chips. An insulator is interposed between the second surface of the first semiconductor chip and the first surface of the second semiconductor chip at portions other than the selected portions. Further, a resin package encapsulates the first and second semiconductor chips so that the outer portions of the leads project outside the resin package.
Abstract: A method for preventing cross-contamination of semiconductor wafers during processing comprising covering a surface portion of a support assembly with a process compatible material, engaging a semiconductor wafer with the support assembly, processing the wafer while it is engaged with the support member, and removing the process compatible material from the support assembly after said material is considered to be contaminated. A shield particularly adapted for this process includes a shield portion made from a process compatible material and a process-compatible adhesive for attaching the shield portion to the support assembly.
Abstract: The present invention provides a bonding structure between a dielectric substrate made of a dielectric material and a packaging substrate made of a heat conductive material involved in microwave integrated circuits. Both the dielectric and heat conductive materials have different coefficients of thermal expansions. The dielectric substrate has a top surface formed thereon with a top metallization pattern constituting impedance matching circuits and a bottom surface being bonded through a soldering agent to the packaging substrate. The bottom surface of the dielectric substrate has a bottom metallization pattern being selectively formed in a predetermined area thereon so that the soldering agent is applied only on the bottom metallization pattern to bond the dielectric and packaging substrates with each other. The bottom metallization pattern may be the same as the top metallization pattern.
Abstract: A chip carrier for a semiconductor chip, the chip having a specified thickness and lateral configuration and size. A conductive holder of the carrier has a main surface including a chip mounting surface portion for mounting the semiconductor chip thereon and a peripheral surface portion surrounding the mounting surface portion. An insulative collar member is affixed to the peripheral surface portion and has inner wall surfaces surrounding the mounting surface portion and defining a recess, of depth and lateral configuration and size dimensions respectively corresponding to those of the chip, for receiving therein and thereby positioning the chip on the conductive holder.
Abstract: Positive mechanical alignment is provided between substrates using micro-bump contacts by forming "detented" conductive bump contacts on one substrate having a concave end which receive and align the generally convex contour of bump contacts on the other substrate. Various configurations of concavities and convexities are described. Flux may be disposed in the concave end of the detented bump contact to promote formation of joints between the concave and convex bump contacts. Both bump contacts may be formed of reflowable material, such as solder, or one or the other of the contacts may be formed of a non-reflowable material which may also function as a standoff between the two substrates. Each substrate is provided with a plurality of bump contacts, and one substrate may be provided with a combination of convex and concave bump contacts corresponding to concave and convex bump contacts on the other substrate. The inventive technique is useful for joining die-to-die, die-to-substrate, or package-to-substrate.
Abstract: A semiconductor device is manufactured by subdividing the chip carrier into a plurality of functional substrates, such as a signal connection substrate, a capacitor substrate, a resistor substrate and a power supply substrate. The several substrates are individually manufactured and tested before they are assembled. Advantageously, the manufacturing and testing of the substrates are carried out in parallel, so as to reduce manufacturing time of the semiconductor device.Each substrate has a top interconnect layer and a bottom interconnect layer. Each interconnect layer has a plurality of bond pads in an identical pattern. The pads are formed using the same design rules, structure, pitch, diameter and fabrication process for each layer. This identity allows the different functional substrates to be electrically interchanged without changing the interconnection layers. Although changes internal in the substrate may be required.
Abstract: A notched insulation gate static induction transistor integrated circuit ording to the present invention comprises an enhancement mode CMOS logic circuit including a notched insulation gate static induction transistor in which a threshold voltage is determined to prevent current from flowing in a standby mode, and a depletion enhancement mode CMOS logic circuit including a notched insulation gate static induction transistor in which a threshold voltage is determined to cause current to slightly flow in the standby mode. The enhancement mode CMOS logic circuit and the depletion enhancement mode CMOS logic circuit are formed on a major surface of a substrate, and the depletion enhancement mode CMOS logic circuit is used in a circuit in which an average power consumption in a switching operation is higher than that in the standby mode.
April 17, 1995
Date of Patent:
December 12, 1995
Small Power Communication Systems Research Laboratories Co., Ltd.
Abstract: An antifuse is provided which includes a first conductive layer, an antifuse layer formed on the first conductive layer, and a second conductive layer formed on the antifuse layer. A portion of the antifuse layer forms a substantially orthogonal angle with the first conductive layer and the second conductive layer. This "corner" formation of the antifuse enhances the electric field at this location during programming, thereby providing a predictable location for the filament, i.e. the conductive path between the first and second conductive layers. This antifuse provides other advantages including: a relatively low programming voltage, good step coverage for the antifuse layer and the upper conductive layer, a low, stable resistance value, and minimal shearing effects on the filament.
Abstract: A semiconductor device comprises a plurality of leads respectively made up of an inner lead and an outer lead, a semiconductor chip electrically connected to the inner leads of the leads, and a package encapsulating at least the inner leads of the leads and the semiconductor chip so that the outer leads extend outwardly of the package. The package has an upper part and a lower part which have mutually different sizes such that a stepped part is formed between the upper and lower parts by the different sizes, and each of the outer leads have a wide part which is wider than other parts of the outer lead extending outwardly of the package only within the stepped part of the package.
Abstract: A memory component has a rectangular semiconductor substrate containing active memory circuits and output terminals on a major surface thereof. An insulating layer on the major surface receives a plurality of metal connection leads, connecting the output terminals to connection pads located on the major surface along only one of longer sides of the substrate. A plurality of additional pads are distributed between the connecting pads and are devoid of connection leads. A memory module comprising several stacked memory components is also described, which uses the additional pads as relays.
Abstract: There is disclosed a field effect transistor having a channel layer, an electron supply layer, and a spacer layer formed between the channel layer and the electron supply layer. The spacer layer has a thickness for spatially separating a two-dimensional electron gas from donor ions in the electron supply layer, and for forming the two-dimensional electron gas in the channel layer by the Coulomb force of the donor ions. The spacer layer material has better high frequency characteristics than that of the electron supply layer.
Abstract: A thermally and electrically enhanced surface mount package with up to at least 600 I/O connections, but possessing the flexibility and simplicity of conventional leadframes. The package includes an integrated circuit die having a plurality of bonding pads, a conductive substrate having a cavity formed therein for receiving the integrated circuit die, and a flexible circuit laminated on the conductive substrate. The flexible circuit includes at least a wiring pattern and an area array of bumps formed on pads at the periphery of the flexible circuit. The flexible circuit may include a plurality of openings through the flexible circuit beneath certain of the pads or traces of the wiring pattern so as to ground the certain of the pads (ground pads) or traces to the conductive substrate.
Abstract: Integrated circuit chip-to-chip interconnections are made via gold pads on each chip that are bonded to corresponding gold pads on a silicon wafer chip carrier. The pads on the chips and/or the pads on the carrier are characterized by texturing (roughening) with a feature size of the order of a micrometer or less, so that each of the pads on the chip can be attached to each of the pads on the carrier by compression bonding at room temperature--i.e., cold-well bonding. In particular, the texturing of the gold pads on the silicon carrier is obtained by etching V-grooves locally on the surface of the underlying silicon carrier in the regions of the pads, thermally growing a silicon dioxide layer on the silicon career, and depositing the gold on the silicon dioxide layer.