Abstract: A high-strength Pb-free solder alloy, based on the Sn--Ag--Zn system, is disclosed. The Pb-free solder alloy contains, in weight percent, 0.2-0.6% Zn, 1-6% Ag, one or both 0.2-0.6% In and 0.2-0.6% Bi, and the balance Sn. The addition of Zn significantly improves the mechanical strength and creep resistance of e.g., Sn--3.5% Ag eutectic solder while maintaining substantially the same level of ductility. The increase in strength is as much as 48% over that of the Sn--3.5% Ag alloy. This strengthening from the Zn additions is attributed to a uniform solidification structure and a substantial refinement of the precipitates in the alloy. Essentially all of the added Zn resides in the more corrosion-resistant, Ag-based, intermetallic precipitates, leaving the Sn-rich matrix primarily free of Zn in solid solution.

Abstract: Pb-free solder alloys based on the Sn-In-Zn system (exemplarily 86:5:9 weight %) are disclosed. Compositions can have a melting temperature in the range 183.degree. C..+-.10.degree. C. and thus can be readily substituted for conventional 40 Pb-60 Sn solder. The novel compositions also can possess superior mechanical properties, compared to the 40/60 Pb-Sn composition, and readily wets copper. Bi and/or Sb may be added to the Sn-In-Zn base to reduce the tendency for the formation of lower temperature phases.

Abstract: A balanced driver circuit which essentially eliminates inductive noise without a power dissipation penalty is disclosed. The balanced driver circuit is similar to a conventional balanced driver circuit however the circuit is impedance matched at both ends and has resistors connected in series with the outputs of the emitter followers in the chip. The resistors are equal in value to a termination resistor less the output impedance of the emitter followers. The impedance between the pair of signal leads, referred to as the primary and secondary leads is equal to the sum of the termination resistors. The current traversing the secondary lead has the same amplitude, but the opposite sign as the current traversing the primary lead. Thus, there is negligible current return through the common ground leads.

Abstract: We have discovered that the strength of arc fusion splices in optical fiber can be adversely affected by particles (e.g., SiO.sub.2 particles) from the electrodes. Disclosed is a method of arc fusion splicing that can substantially increase the probability that a given fiber splice will meet a given strength requirement. The method comprises initiating the arc in a "cleaning" position selected such that the probability of incidence on the fibers of particles from the electrodes is relatively low, followed by changing the relative position between the electrodes with the arc therebetween and the fibers to the conventional "heating" position and forming the splice.

Abstract: Disclosed is an apparatus which can serve to detect, count, size discriminate and analyze the chemical composition of particles in the air or process gases. In a preferred embodiment, the particles enter via a capillary into a differentially pumped chamber. A pulsed laser which is continuously fired is focused at an opening in the chamber. When the particles come into the path of the laser beam, the particles are fragmented and ionized. A dual time of flight mass spectrum is produced, recorded with an oscilloscope and analyzed with a computer. The mass spectrum information enables the determination of the chemical nature and concentration of the species of the particles, the particle size and the elemental composition of airborne particles in real time. Once these parameters are determined the source of the particles can be determined and eliminated from the environment and process. Thus, the inventive apparatus is advantageously used in conjunction with a facility, i.e.

Abstract: This invention is embodied in an apparatus for assessing the effects of controlled amounts of well-characterized ionic or other particles on the reliability of electronic components. The chamber includes a high efficiency filter that purifies the input air and a recirculating system which ensures substantially laminar, constant velocity air flow, controllable humidity, and steady state conditions throughout at least a portion of the chamber. Particles are introduced into the chamber from a particle generator through a series of output ports that ensure a uniform concentration of particles throughout at least a portion of the chamber. Substantially constant conditions are achieved by constantly introducing new particles into the chamber, withdrawing a continuous flow of particle-laden air from the chamber, removing essentially all the particles from the particle-laden air withdrawn from the chamber and introducing a continuous flow of filtered air into the chamber.

Abstract: New solder compositions which can have improved mechanical properties are disclosed. In a preferred embodiment, the solder comprises a matrix material and magnetically dispersed particles. A desirable dispersion of the magnetic particles in the matrix material, is accomplished by applying a magnetic field to the molten matrix material containing magnetic particles and solidifying it in the presence of the magnetic field. The particle-dispersed microstructures improve the mechanical properties of the solder composition. The improved solder composition can be made into a powder to be used in solder paste, cream or reshaped while substantially retaining the improved mechanical properties.

Abstract: In accordance with the present invention, a silicon device fabricated on a (100) silicon substrate is provided with a (111) slant surface and an electrical contact comprising epitaxial low Schottky barrier silicide is formed on the (111) surface. For example, low resistance rare earth silicide contacts on V-groove surfaces are provided for the source and drain contacts of a field effect transistor. The resulting high quality contact permits downward scaling of the source and drain junction depths. As another example, rare earth silicide Schottky contacts are epitaxially grown on V-groove surfaces to provide low voltage rectifiers having both low power dissipation under forward bias and low reverse-bias leakage current.

Abstract: An induction furnace for reflowing a portion of an optical preform in order to draw a lightguide fiber therefrom. The furnace has an axially located tubular iridium susceptor which is centrally disposed within a beaker and a sleeve is positioned concentrically around the susceptor. The sleeve is surrounded by an insulating grain. A high frequency coil is energized to couple its electromagnetic field to the iridium susceptor to heat and reflow a portion of the preform in order to draw the fiber therefrom. The furnace housing is sealed to provide an inert, non-oxidizing atmosphere for the iridium susceptor.

Abstract: The present invention is embodied in a technique for precise and accurate height control in fabricating solder bumps or joints formed from a solder bump or bumps. A solder bump is formed by reflow of a conical solder body having base diameter D, height H and cone angle .theta., and has truncated sphere shape, with height h and truncation diameter d. We have found that D, H, and d can be selected such that .differential.h/.differential.H is small (typically .ltoreq.0.5), indicative of relative insensitivity of the bump height to variation in the height of the conical solder body. The inventive process is also applicable to a component (e.g., a laser) solder-bonded to a substrate, and can provide previously unattainable control of the spacing between component and substrate.

Abstract: By on-chip modification of a conventional balanced driver to yield special voltage levels, the power dissipation of a balanced, terminated transmission line circuit can be reduced by 50% or more relative to a conventional balanced driver or 25% or more relative to a conventional unbalanced driver. This reduction in power dissipation not only applies to point-to-point interconnections but also applies to bused interconnections. The low power balanced driver circuit can be implemented using ECL, BiCMOS, GaAs and CMOS technologies and no modifications are needed to the associated differential line receiver. Thus, the significant benefits of balanced interconnections, namely reduced crosstalk, increased noise immunity, and elimination of ground noise can be realized with a significant reduction in power dissipation.

Abstract: This invention is an apparatus which comprises a low reflection optical fiber termination. The apparatus comprises an optical fiber having a core, a cladding and a designated end. The core of the fiber has an effective refractive index N (exemplarily 1.484.+-.0.026). A terminator having a refractive index approximately equal to N (e.g. to within .+-.3.5%) is attached in such a manner that the terminator and the designated fiber end are in intimate contact. The closer the refractive index of the terminator is to the refractive index of the core of the fiber, the less back reflection occurs. A curable polymer having a high refractive index can be used to coat the terminator and a portion of the fiber. There is no need to polish, bend, cleave, twist or taper the end of the optical fiber prior to attaching the substrate to the optical fiber. Thus, the apparatus can be readily and inexpensively practiced not only in the factory but also in the field.

Abstract: A portable radio telephone device which is in the form of a wristwatch which is fastened to the user's wrist via a strap. The telephone device is comprised of two main components, a case and a strap. The case has a display and a transceiver. The strap or band has at least a top and a bottom layer which are attached to the case. The top layer of the band is releasable in the proximity where the case and strap meet. However, the top layer remains connected to the bottom layer of the strap by a pivotable hinge. The pivotable hinge is typically located opposite the case and permits the top layer to be rotated. The length of the top layer can be increased either by repositioning the case or having additional layers located beneath the top layer. The speaker is located on the end of the released top layer. The microphone is located on the band. When the top layer is released and rotated, the speaker is located in the palm of the user's hand and the microphone is positioned along the inside of the user's forearm.