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Components, Hybrids, and Manufacturing Technology, IEEE Transactions on

Issue 2 • Date June 1980

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Displaying Results 1 - 16 of 16
  • Foreword

    Page(s): 209 - 210
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    Freely Available from IEEE
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  • Molybdenum in the Electronics Industry

    Page(s): 232 - 236
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    Molybdenum, which is widely used in the electronics industry, is usually a misunderstood metal. An introduction to its manufacture and present use is presented. The new development of cladding molybdenum with various materials and/or elements, which not only improves the reliability of the electronic device but also reduces production costs, is described. View full abstract»

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  • Statistics of Wire Lengths on Circuit Boards

    Page(s): 305 - 306
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    The expected length of connecting wire on a rectangular board has been found based on random starting and stopping points. Two cases of connections are considered. One case uses x and y motion and the other uses a direct path. The results are important in the consideration and design of circuit performance in electronics packaging. The same probability distributions are also directly applicable to the problem of searching on tape and arrays. View full abstract»

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  • Thick-film Technology: An Introduction to the Materials

    Page(s): 211 - 225
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    The use of thick-film technology to manufacture electronic circuits and discrete passive components continues to grow at a rapid rate worldwide. When applied to hybrid microcircuits, it can be viewed as a means of packaging active devices, spanning the gap between monolithic integrated circuit chips and printed circuit boards with attached active and passive components. The strength of the thick-film approach is a consequence of function, size, and unit cost trade-offs; advances in materials have played a major role relative to each of these factors. Thick-film materials are developed to meet needs defined by electronic circuit design and process engineers. A general understanding of thick films is provided from a materials standpoint, particularly for the new engineer. Background is developed for a basic, yet simple, understanding of the components that make up resistor, conductor, and dielectric compositions, of processing, and of the properties of the final thick-film composite structures. View full abstract»

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  • A Low Pressure Capacitance Type Pressure to Electric Transducing Element

    Page(s): 261 - 265
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    A great variety of pressure transducers with electrical output have been developed for pressure measurements using a number of different operating principles. Virtually all pressure to electric transducers consist of a fluid pressure sensitive member which converts fluid pressure into mechanical movement or force. A new pressure to electric transducer is described. It is a low pressure (0 to I psig) device having a capacitor configuration in which the transducing element is an elastic capacitor consisting of integrally bonded elastic layers, which make up the dielectric core and conducting plates of the capacitor. The element has a nominal capacitance of 100 pF and a pressure sensitivity of approximately 1.3 pF/in of water pressure. The characteristics of the pressure to electric transducer are discussed and include the element's sensitivity to pressure and longterm stability characteristics. The effect of temperature on element performance is also discussed. View full abstract»

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  • Design of an Internal Fuse for a High-Frequency Solid Tantalum Capacitor

    Page(s): 244 - 249
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    A miniature fuse module was designed and incorporated into a solid tantalum capacitor for high-frequency bypass applications. The fuse consists of a fine bimetallic wire which reacts exothermically upon reaching a critical initiation temperature. It is housed in an electrically and thermally insulative body to minimize fusing energy. The desirability of having fused devices is discussed. Design constraints, in particular those design considerations which minimize inductance and series resistance while optimizing fusing characteristics, are presented. Construction techniques to produce fuse assemblies and join them to capacitors are reviewed, and parametric measurements of fused and unfused devices are compared. Factors affecting the amount of energy required to actuate the fuse and the reliability of actuation are identified. Typically, fuse actuation occurs within 25 ms of short circuit capacitor failure and requires between 1.5 and 2.5 A to initiate with the total energy used being less than 150 mJ. A device can now be produced that withstands switching and transient surges without incident while protecting circuits and equipment from disruption and damage caused by short circut capacitor failures. View full abstract»

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  • Contamination Control in Lead Bonding to Thick and Thin Films

    Page(s): 281 - 287
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    Degraded wax residues from processing steps have been found to be a major source of contamination on beam lead devices for hybrid microcircuits. Two avenues of approach were used to solve bonding problems traced to this contamination: 1) a search was initiated for a more thermoxidatively stable and more easily removed wax, and 2) an effort was made to determine the level of cleanliness necessary for successful bonding and the most efficient method of attaining this level. A series of halocarbon waxes (polytrifluorochlorocthylenes) was found to be stable both chemically and thermally. The carbon contamination levels were decreased after improved solvent cleaning techniques and measured ~2 rim. This level compares with values as high as 9 nm after typical solvent cleaning. Plasma and ultraviolet cleaning both reduced carbon residues to 0.2-0.8 nm. Ball bonds made with weld forces of 1.0-1.5 N were successful on ultraviolet (UV) and plasma cleaned surfaces near 200°C and near 327°C for surfaces cleaned by improved solvent techniques. The beeswaxes presently used had adequate and better bondability than the more stable halocarbon waxes when only solvent cleaning was used and temperatures did not exceed 125°C to avoid charring. View full abstract»

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  • Ceramic Humidity Sensors

    Page(s): 237 - 243
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    A novel humidity sensor using a MgCr204-TiO2 porous ceramic has been developed for an automatic microwave oven. Physical properties of the MgCr204-TiO2 ceramic, construction and humidity characteristics of the sensors, and outlines of the control of the automatic microwave oven by humidity sensing are described. The MgCr204-TiO2 ceramic exhibits a typical porous structure and semiconduction. The porous ceramic easily absorbs water vapor throughout the pores. The ceramic grain surfaces behave like electrolytes. The ceramic humidity sensor utilizing its humidity sensitive effects and rejuvenating response to heat treatment exhibits high humidity and long term stability. The novel humidity sensor has been applied in many processes such as microwave ovens, air conditioners, dryers, etc. View full abstract»

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  • A New Mechanism for Lateral Erosion

    Page(s): 292 - 296
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    Although miniature dry reed sealed contacts are in increasing demand in telecommunications, their use is often limited to low current switching. Attempts to use dry reed contacts to switch higher currents lead to resistance failures or failures to release after a relatively small number of operations. These premature failures are always due to the formation of pips and craters resulting from localized arc erosion. It has long been recognized that the delocalization of the erosion would lead to better utilization of the contact material and consequently to a longer contact life. A new mechanism promoting lateral erosion is demonstrated and shown to operate under various electrical loads. The spreading of the erosion is linked to the microstructure of the precious metal layer with the most favorable structures having a high density of voids. The generation of the voids depends on the method of deposition of the contact metal layers. They can be readily produced in the case of electroplating by codepositing foreign molecules which can be decomposed by a subsequent heat treatment. A comparative study is presented of the wearability under electrical load of reed sealed contacts using either conventional dense gold or heat-treated void-containing gold as the contact material. Under diversified electrical stresses, the void-containing gold contacts show an improvement in mean life to failure ranging from a factor of seven to ten. View full abstract»

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  • Ion-Implanted p-Resistor Reliability

    Page(s): 258 - 261
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    One of the key aspects of large-scale integration in bipolar technology depends on the use of high valued resistors. Ion implantation can lead to higher valued resistors not possible with diffused technology. Two different process technologies, pre-emitter and post-emitter, for making ion-implanted resistors are described. Also described are measured profiles, reliability studies carried out on p-resistors made by the two technologies, and a model describing the resistor drift with voltage and temperature. View full abstract»

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  • Connector Finishes: Tin in Place of Gold

    Page(s): 226 - 232
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    Gold has been the natural choice as a contact material for low-voltage circuits (dry circuits) because of its properties and characteristics. In addition to having low electrical resistivity, it is not attacked by most chemicals and does not form surface oxides and sulphides so that good electrical contact is made with minimal force, even at low voltages. The rapidly escalating price of gold has motivated the investigation of less costly connector finishes. Some of these developments are reviewed. In particular, tin and its alloys form thin oxide films which may be easily broken, so that low-resistance metal-to-metal contact can be established with the underlying tin base. Changes in connector design are aiding the development of new contact materials. View full abstract»

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  • Wear of Silver-Graphite Brushes Against Various Ring Materials at High-Current Densities

    Page(s): 288 - 291
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    A study has been carried out to evaluate noble metals for potential use as ring materials for high-speed high-current applications. A pin-on-disk friction apparatus was constructed so as to allow sliding tests to be carried out at high speeds and high-current densities in controlled environments. The pin material was a silver-graphite brush composite while the flat material was one of the elemental metals nickel, copper, silver, gold, platinum, palladium, rhodium, ruthenium, rhenium, or iridium. The pressure was 0.2 N/mm2, the current density was 0.8 A/mm2, and the sliding speed was 4 m/s. The friction, wear, and electrical resistance were determined in wet CO2 and dry air. In general, and surprisingly, materials which give high friction give low wear although, in fact, both the friction and the electrical resistance values covered a narrow range. The wear results are not in agreement with earlier data obtained during tests of silver pins sliding against the same metals at much lower loads, speeds, and electrical current densities, in which case the low wear metals were those with low metallurgical compatibility against silver, or else metals with a hexagonal crystal structure. In these new tests, the wear behavior at high speeds and high-current densities with silver-graphite brushes obeys essentially the same compatibility relationships, but referred to the graphite. The best performance in terms of low wear was provided by the metals rhodium, palladium, and platinum. View full abstract»

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  • A Fracture Mechanics Approach to Structural Reliability of Ceramic Capacitors

    Page(s): 250 - 257
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    Physical defects, such as cracks, spa!Is, and delaminations, may be associated with a significant percentage of the multilayered capacitors produced for high reliability applications. These defects may lead to severe cracking of the capacitors and eventually to their electrical failure. This paper presents a fracture mechanics approach to the reliability assessment of physically defective capacitors used under high mechanical stress conditions. This approach requires both the characterization of the material properties (fracture toughness, elastic moduli, et cetera) of the multilayer capacitor and of the part's application (environment and operational conditions). From these results the mechanical reliability of a capacitor can be estimated for different system applications and realistic limits can be determined for the allowable sizes and types of defects. View full abstract»

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  • A New Bilateral Optoisolator Circuit

    Page(s): 266 - 280
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    A simple optoisolator circuit is proposed which has bilateral transmission. It is composed of two optoisolators in a positive feedback arrangement without going into instability. The experimental and analytical results show that this circuit simulates not only the transmission gain or attenuation corresponding to the step-up or step-down transformer, but also the bilateral amplification. Other features, such as an impedance buffer, improvement of the frequency response, and high packaging density, are also achieved. View full abstract»

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  • The Lubrication of Gold Surfaces by Plasma-Deposited Thin Films of Fluorocarbon Polymer

    Page(s): 297 - 304
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    Thin films of fluorocarbon material have been deposited on gold-plated substrates by the technique of RF-induced plasma polymerization of fluorocarbon monomer gases. The deposited films have been evaluated for suitability as contact lubricants by determining the friction and wear characteristics of the substrates in the presence and absence of the film and by a comparison to substrates coated with microcrystalline wax, a typical contact lubricant currently in use. The data were obtained using a rider/flat wear tester. Electrical conduction through the films has been characterized by contact resistance measurements. The results show that there exists a range of film thicknesses that provide a significant improvement in friction and wear relative to unlubricated substrates at a low ohmic contact resistance. The microcrystalline wax, however, provided the best protection. View full abstract»

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Aims & Scope

This Transaction ceased production in 1993. The current publication is titled IEEE Transactions on Components, Packaging, and Manufacturing Technology.

Full Aims & Scope