Abstract: A multichip module is assembled using flip-chip bonding technology, a stencil printable solder paste and standard surface mount equipment for interconnecting signaling input/output contact pads on devices within such multichip module.

Abstract: A fragile device, such as an integrated circuit chip or a multichip assembly, is packaged by first dispensing a sol surrounding the sides of the device. The sol is laterally confined by means of a rim member typically made of a pre-molded plastic material. The amount of the sol dispensed is not sufficient to run over the top of the rim member. The sol is then heated to form a gel. If desired, a cover member can be put into place onto the top surface of the rim member, for the purpose of additional mechanical protection of the fragile device, for example.

Abstract: The specification describes an interconnect strategy for memory chip packages to reduce or eliminate alpha particle contamination from the use of high lead solder interconnections in the vicinity of semiconductor memory cells. In the primary embodiment a high tin solder is recommended. A multi-layer under bump metallization is described that is compatible with high tin solders and flip-chip solder bump technology.

Abstract: The specification describes a method for dispensing IC chips from a chip carrier tape for a flip-chip assembly operation. In a conventional assembly operation, the solder bumped side of the chip is the top side of the chip as loaded on the tape, and is normally the side of the chip that engages the head of the pick tool. For flip-chip assembly it is necessary to invert the chip for solder bonding to an interconnect substrate. In the technique of the invention, the chip carrier tape is inverted and inserted into the dispensing machine upside down. The IC chips are then ejected through the back of the tape instead of being lifted from the from of the tape. In this way the pick tool head engages the back side of the solder bumped chip and the chip is in the proper orientation for flip-chip placement and bonding on the interconnect substrate.

Abstract: Cleaning of a micromimiature high-density flip-chip assembly is carried out by spinning the assembly while applying cleaning fluid to a central portion of the assembly. Confinement of the cleaning fluid to a critical interconnection space of the assembly is ensured by a centrally apertured cover that resiliently engages the top of the assembly. During spinning, cleaning fluid is introduced through the aperture in the cover and is directed into and confined to flow radially in the interconnection space.

Abstract: The bottom and side surfaces of an electronic device, such as an integrated circuit chip or a multichip assembly, are surrounded by a soft gel medium. The gel medium is laterally confined by a rigid plastic rim that is epoxy-bonded in place along its perimeter. A plate, made of plastic or metal, can be attached to the top surface of the rim, in order to provide a cover for the package.

Abstract: A novel packaging of semiconductor elements, such as MCM tiles, with a variety of printed circuit or wired boards (PWB), the packages occupying a small size, at least in the vertical direction, relative to prior art OMPAC devices. The MCM tile includes an interconnection substrate with peripheral metallizations and at least one chip or integrated circuit (IC) mounted on the substrate by solder reflow or conductive adhesive technology. The PWB which may be a single level or a multilevel, is provided with an aperture for accommodation of at least one chip therein. Depending on the type of interconnection between the substrate and the PWB, the aperture may be larger than the substrate of the MCM tile for wire bonding interconnection or smaller than the substrate for solder reflow or conductive adhesive interconnection. In the wire bonding case, the MCM tile is positioned within the aperture resting on the surface of the PWB or of a structural member or of a heat sink which encloses one end of the aperture.

Abstract: A composite spin lock prepulse method compensates for magnetic field inhomogeneities in objects or materials under study using nuclear magnetic resonance (NMR). The effective magnetic field seen by an object or material under study using NMR often is characterized by an off-resonance component, which results in the magnetization of the object or material having a component that diverges from the intended orientation after RF pulses. The method according to the present invention recognizes and utilizes the observation that aligning the off-resonance component of the magnetization in the x-z plane can be achieved when the amplitude of a preceding 90.degree. y flip pulse is known, and that the effective field can be placed in alignment with the resulting magnetization, if necessary or desired, by adjusting the amplitude of the locking pulse as a function of the amplitude of the flip pulse.

Abstract: A card screen and a lickerin screen are provided for a forty inch carding machine having the usual side ribs and end blanks. The grid bars in both the card screen and the lickerin screen are of triangular configuration in cross-section and are structured to provide increased air flow for the removal of trash. One side of each grid bar extends downwardly in use at an angle of about 50.degree. to the radii of the main cylinder, or lickerin roll, another side extends radially from the main cylinder, and the third side extends between the first two sides in closely spaced substantially parallel relation to the main screen. There is no center rib and the grid bars extend the entire distance between the side ribs.

Abstract: An add-on system as disclosed for use with an existing multilevel antennae switching matrix of the type having a plurality of input ports, each supplied by a respective input signal source with at least one unused input port being available and a plurality of output ports are connected to receivers. The add-on system uses a plurality of switching devices which are each selectively operable to couple each of the input signal sources to a different one of the unused input ports. This provides that when an attempt to effect an interconnection between a desired one of the input ports and a desired output port is blocked then the input signal source which supplies the desired input port associated with an attempt connection is coupled to any one of the unused input ports for facilitating the connection at that port to the desired output port.

Abstract: A technique for monitoring the drawdown zone of an optical fiber preform is disclosed. The technique involves detecting the caustic rays emanating from the drawdown zone. Analysis of these rays allows one to determine the geometric properties of both the drawdown zone and the resultant optical fiber. In addition, detailed information concerning the index of refraction distribution in the fiber may be obtained. The process is amenable to realtime applications during the drawing of an optical fiber.