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Components, Hybrids, and Manufacturing Technology, IEEE Transactions on

Issue 1 • Date March 1987

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Displaying Results 1 - 19 of 19
  • Foreword

    Page(s): 2
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    Freely Available from IEEE
  • In situ Examination of Segregation and Wear Processes of Precious Metal Electrical Contact Alloys

    Page(s): 47 - 55
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    The electrical contact resistance and friction coefficient of gold-based (ASTM B541) and palladium-based (ASTM B540) precious metal electrical contact materials have been measured simultaneously with au in situ pin-on-plate device in a scanning Auger analytical system. Intermittent surface analysis of the wear track was performed as wear of the contact surface progressed without repositioning of the pin in the wear track. The wear process was one of adhesive wear. Initially, a prow formed on the pin, and subsequently, debris was transferred back and forth between the pin and plate. The identity and partial pressures of gases in contact with the wear surface were controlled precisely, thereby avoiding exposure to unwanted gas phase contaminants. The friction coefficient varied from 2.2 to 2.6 for high vacuum ambients containing oxygen (10-6 torr) or nitrogen (10-7 torr) but was 1.6 for an atmospheric ambient (700 torr) of 0.05 oxygen in nitrogen. In comparison, the friction coefficient was <0.5 in laboratory air. The electrical contact resistance was < mOmegfor all test conditions but varied inversely with the friction coefficient. Segregation of sulfur to the wear track was observed in situ in the 700-torr ambient after as few as ten wear cycles. The friction coefficients for these tests were larger than for previous experiments; the increase was attributed to surface depletion of copper. View full abstract»

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  • An Electric Double-Layer Capacitor With Activated Carbon Fiber Electrodes

    Page(s): 100 - 102
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    An electric double-layer capacitor with activated carbon fiber (ACF) electrodes has been developed. The capacitor features ultrahigh capacitance (0.033 F-0.68 F) in a small thin structure (13.5-mm diameter x 8 mm or 21.5-mm diameter x 9 mm). A technique for carbonization and activation of the phenolic resin-based fiber and a plasma spraying technique for the metal electrodes enabled us to make the small-size capacitor for memory backup use and as a replacement for small-size batteries. Micropores larger than 2 nm in diameter in the ACF effectively work to form an electric double layer which results in a highperformance capacitor over a wide temperature range from -25 to 70°C. View full abstract»

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  • Sliding Studies of New Connector Contact Lubricants

    Page(s): 24 - 31
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    A widely used lubricant for the contacts of separable connectors is a five-ring polyphenylether fluid. However, the heat to which electronic equipment can be continuously subjected due to increased packaging density and to elevated ambient temperatures may be beyond the limit of thin coatings of this fluid due to its volatility. A search for new lubricants was therefore initiated, and the first part of this work is described. A friction and wear evaluation of various organic fluids and a grease using clad DG R-156 and cobalt-gold electroplate contact materials was conducted. It was found that a six-ring polyphenylether and viscous perfiuoroalkypolylether fluids (>500 centistokes (cSt) at 25°C) · are good lubricants and possess other desirable characteristics such as very low volatility, thermal stability, and oxidation resistance. The second part of the study, presented elsewhere, develops quantitative life data for the several fluids and makes recommendations concerning lubrication practices. View full abstract»

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  • Problems Associated with Quality control Sampling in Modern IC Manufacturing

    Page(s): 107 - 110
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    Existing sampling plans are not very efficient in situations when a fraction of defective items is on the order of 0.0001. They usually command a 100-percent inspection, but it still does not provide for 100percent quality since in semiconductor manufacturing the inspection is never totally reliable and can easily introduce an error of almost the same order as the fraction of defectives. Skip-lot strategies can rarely be used because most of the customers frequently require inspection of every shipped lot. An inspection policy is suggested which combines the ideas of various sampling strategies and provides a guarantee against undesirable levels of average outgoing quality as well as protection against poor quality on a lot-to-lot basis. The method is based on observing the number of good items between defective ones and shifting to a 100percent inspection when certain conditions are not met. View full abstract»

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  • The Steady-State Analysis of Networks Containing Uniform or Nonuniform Distributed RC Structures

    Page(s): 75 - 81
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    A number of lumped models which have been used to simulate distributed RC networks have certain limitations. To overcome these limitations an exact model for inclusion into a nodal analysis program is proposed. The accuracy of this model is demonstrated and the incorporation of frequency-dependent dielectric loss into the model is discussed. The principal use of the model, in the simulation of trimmed distributed networks in active filters, is described, and some representative parameters are given. View full abstract»

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  • Improved Contacts in Glass-Encapsulated Capacitors

    Page(s): 103 - 106
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    Ceramic chip capacitors hermetically sealed into glass sleeves are used extensively in the electronics industry. However, glass-encapsulated capacitors can loose contact at the termination lead wire. To improve the contact reliability, a brazing operation is suggested that coincides with the present sealing temperature of 720°C. For this purpose a nickel coating over the conventional termination and a braze paste for use in nitrogen was developed. It was found that an electroplated nickel coating and a braze paste consisting of "Incusil 15" were most satisfactory. However, the brazing operation increases the dissipation factor from 0.6 percent for conventional glass-encapsulated capacitors to about 1.8 percent for brazed and sealed capacitors. To test the contact reliability, the capacitors were temperature cycled between 30 and 210°C for up to 1000 times. In this test seven of the 36 conventional glass-encapsulated capacitors failed through loss of contact, whereas none of the 180 brazed and sealed capacitors failed. This result is a significant improvement in the contact reliability of glass-encapsulated capacitors. View full abstract»

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  • Comparison of the Inherent Arc Erosion Behaviors of Silver-Cadmium Oxide and Silver-Tin Oxide Contact Materials

    Page(s): 56 - 62
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    Powder metallurgically produced silver-cadmium oxide and silver-tin oxide materials with equal volume percentages of oxide were electrically tested to evaluate and compare the effects of the different oxides on the arc erosion behaviors. The silver-tin oxide material had less steady-state erosion, better weld resistance, and higher contact resitance compared to silver-cadmium oxide. The eroded surface structures were examined and used to explain these quantitative results. The arc-affected erosion surfaces of the silver-tin oxide material consisted of silver, tin oxide, and porosity distributed across the contact surface, yielding Iow weld strengths but high contact resistance. The silver-cadmium oxide eroded surfaces had large elevated oxide-depleted areas which yielded Iow contact resistance but higher weld strengths. Theories of how these 'eroded surface structures developed under the given conditions are presented for the silver-cadmium oxide and the silver-tin oxide materials. View full abstract»

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  • Mass Transport in Stationary Contact Points

    Page(s): 89 - 99
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    Recent experimental work with direct current on aluminum-aluminum contacts has demonstrated that the electron flow through the narrow areas of real contact is accompanied by a flow of atoms. Three possible atomic transport mechanisms are considered: electromigration, thermotransport, and diffusion. Their relative contributions to the mass flow are derived based upon accepted models for spatial distribution of current and temperature close to the contact point. When applying material parameters as for aluminum, electromigration appears to be the dominating effect. The migration rate varies strongly with temperature and is also expected to be far higher along grain boundaries, dislocations, etc., than for volume migration through the metal lattice. The process of current-induced mass transport through the contact points is, according to the derived model, nonstationary and may be significant to the electrical properties of the contact. View full abstract»

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  • A Study on the Thickness of Rhodium Oxide Film Produced by the Surface Deactivation Treatment of Rhodium-Plated Contact Reed Switches

    Page(s): 42 - 46
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    Surface deactivation treatment, i.e., oxygen treatment at high temperatures, was invented to prevent adsorption and catalysis of rhodium-plated contact surfaces. This oxygen treatment was also found to be effective to inhibit soft sticking, a kind of locking phenomena that is one of the most serious problems in the field of electrical contacts. So far, oxygen on rhodium-plated contact surfaces treated with oxygen at 450°C or above is found to be present in the state of rhodium oxide (Rh203). However, research on the thickness of rhodium oxide film remained to be carried out. This time the rhodium-plated contact surfaces are examined precisely to obtain information about the thickness of rhodium oxide film produced by oxygen treatment at 450°C or above, by utilizing ellipsometry and Auger electron spectroscopy. As a result of these investigations, it is found that the thickness of rhodium oxide film by oxygen treatment at 450°C is about 60 A and that the thickness of rhodium oxide film increases as the oxygen treatment temperature rises. View full abstract»

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  • Electronic Connector Contact Lubricants: The Polyether Fluids

    Page(s): 32 - 41
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    The results of a search for connector contact lubricants which have higher service temperatures than a widely used fivering polyphenylether (5-PPE) fluid are reported in a companion paper and continued here. Comprehensive studies of the mechanisms of lubricant depletion and their applicability to fluid coatings were made. They show that the maximum service temperature to which contacts with a coating from a 0.5-wt% solution of the 5-PPE in a volatile solvent, such as 1,1,1trichloroethane, may be continuously subjected is about 30-50°C assuming a product life of 20 years. The temperature limit depends on the configuration of the connector and the criterion of failure. A 2.0-wt% coating of the 5-PPE can be used at 40-60°C. A 2.0-wt% coating of a sixring polyphenylether (6-PPE) fluid has an estimated maximum service temperature of 85-110°C at the same conditions. Furthermore, it is effective at temperatures below 0°C, which is less than its pour point. Low-volatility viscous perfluoroalkylpolyether (PFAE) fluids are good lubricants but can be depleted by surface migration, unlike the PPE's which are nonwetting, and may contaminate surfaces adjacent to the connector. They are therefore less desirable than PPE's. It is recommended that a 2.0-wt% coating of 6-PPE be used when a connector contact lubricant having a broad service temperature range is required. The 5-PPE is not an ideal lubricant for long-lived applications much above room temperature but is effective within its lower maximum operating temperature limits. View full abstract»

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  • Fretting corrosion of Tin-plated copper alloy

    Page(s): 63 - 67
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    The rise in contact resistance of a tin-plated copper alloy under cyclical minute motion has been studied for both dry circuit and with electrical loads. In the range of circuit voltage and current investigated, the electrical conduction through slightly corroded contacts is shown not to be affected by the electrical load. For moderately corroded contacts, the resistance characteristic shows a sustained plateau near the melting voltage of Sn; and for severely corroded contacts, plateau occurs in the resistance range corresponding to the voltage range of the melting, sublimation, and decomposition of the oxides and the vaporization of tin. Based on our observation, a consistent picture of fretting corrosion and electrical conduction through such contacts is presented. View full abstract»

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  • Fretting Corrosion of Tin-Coated Electrical Contacts

    Page(s): 68 - 74
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    Fretting corrosion is one of the most important failure mechanisms for separable contacts with base-metal materials. The fretting corrosion behavior of a specific tin-coated connector contact has been investigated. A periodic relative displacement between the connecting parts was induced, while the contact resistance was monitored continuously. For various contact forces the experiments show a strong and reproducible relationship between the amplitude of the imposed displacement and the number of cycles to failure. This makes it possible to indicate the conditions, in terms of contact force and microdisplacement, in which a reliable contact performance can be obtained with tin-coated electrical contacts. View full abstract»

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  • Bouncing of Contacts Under Current Load(The Influence of Mechanical System Parameters and Load Current on the Closing Process of Electrical Contacts)

    Page(s): 122 - 126
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    The closing process of real contactor contacts with load current are described. The experiments were carried out while varying the parameters of the mechanical system of the real contactor and the load current. The experimental data analysis of the process· is given. The results of the statistical processing of the experiments are considered. View full abstract»

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  • Chip Alignment Templates for Multichip Module Assembly

    Page(s): 111 - 121
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    Future high-performance large-scale digital systems will increasingly require high-density multichip hybrid packaging techniques. Chip attachment by flip-chip mounting, as in the well-established eontrolled-collapse solder-bump contact approach, has several fundamental advantages over the more familiar wire-bonded hybrid assembly approach. However, testing of flip-chip mounted assemblies and replacement of defective parts, along with the alignment of chip bonding pads to substrate pads, involves substantial practical difficulties. A chip alignment template, aligned to and permanently mounted on the hybrid substrate, is proposed. Anisotropic etching of silicon wafers provides a high-precision technique compatible with batch fabrication of the templates. Fabrication of such templates and factors influencing chip alignment accuracy are discussed. View full abstract»

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  • Pb-Sn Alloy Microstructure: Potential Reliability Indicator for Interconnects

    Page(s): 82 - 88
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    Investigation of the microstructure and chemistry of Pb-Sn alloy interconnects by scanning electron microscopy (SEM) and X-ray microanalysis shows that certain physical and chemical characteristics of the Pb-rich and Sn-rich phases are indicative of crack formation during temperature cycling. Those solder alloy interconnects that crack when temperature cycled exhibit significantly different microstructure patterns compared with solder interconnects that do not crack. Energy dispersive X-ray (EDX) data indicate that cracking is more pronounced when impurities such as Al, Au, or W are inadvertently introduced into the alloy material. View full abstract»

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  • Silver-Metal Oxides as Contact Materials

    Page(s): 127 - 134
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    After a short historical survey, the requirements for silvermetal oxide are explained. These requirements are compared with the technical contact properties of the materials, which are discussed for a large number of the most different silver-metal oxides with regard to · welding on make, · erosion on make, · temperature rise of closed contacts after a large number of switching operations, · erosion on break, · arc movement in the magnetic field, · arc extinction. The effect of a third component, dosing materials in low concentrations, is also included. This is followed by a description of the most important methods of manufacture. Starting from internal oxidation on the one hand and sintering on the other, as well as methods which are based on both technologies, the stages of production are represented in diagrammatic form. The results of a large number of experimental investigations lead to the ranges of application of silver-metal oxides and their limits compared with other materials. Looking to the future, it is shown that Ag/CdO will probably be replaced, if the development continues, by the essentially more environmentally acceptable material Ag/SnO2during the next 5-10 years. View full abstract»

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  • Sliding Monolithic Brush Systems for Large Currents

    Page(s): 3 - 17
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    An improved system for collecting and transferring electrical current between relatively moving parts, as in a homopolar machine, is described. The use of solid brushes for collecting or transferring current in systems involving relatively moving parts, such as motors or generators, has been proven reliable and reasonably efficient for many commercial and industrial applications. With recent advances in the design of electrical machinery, particularly involving power-rated homopolar machines, the need has arisen for improved systems capable of more efficiently collecting and transferring machine current. This need is primarily due to the combined much greater electrical currents and speeds required to generate more power or transmit more torque within a given volume than was previously possible. The disadvantages and inadequacies of present current collecting and transfer systems are eliminated by providing a new solid brush type current collection system which selectively uses compatible materials for the moving and stationary contact members. These contact members are operated in an atmospheric environment which utilizes nonoxidizing gases, such as carbon dioxide, having either water or organic additives for the purpose of operating the collector system at higher temperatures, higher current densities, and higher velocities than is possible with conventional systems. The system development of compatible brush and ring materials, ambient environment gas and vapors, and the need for adequate cooling are presented here. Preliminary test results of the developed system in a machine environment reveal a strong feasibility for meeting the current collection goal of 155 A/cm2, a requirement which designers of advanced machines consider viable for a number of high power applications of interest. To transfer current in the most efficient artless manner, the solid brush collector system will require forced cooling to maintain the interface temperature at relatively Iow values thus to achieve Iow friction and Iow wear rates of the sliding contact members. View full abstract»

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  • Monitoring, Controlling, and Resolving Connector-Related Concerns

    Page(s): 18 - 23
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    lnterconnection components like connectors, pins, and printed wiring board fingers are usually required to satisfy manufacturers and/or users specifications prior to being used. This entails monitoring such components for quality and, if necessary, controlling or resolving problems that arise. The following examples of such situations are discussed: 1) incoming material inspection procedures for monitoring quality of precious metal inlays used as contact finish, involving contact resistance measurements; 2) pass-fail requirement testing and demerit rating of discolored pins with electroplated gold finishes; 3) cleaning procedure for excessive lubricant in contact area; 4) controlling for uniformity in coverage of lubricant on contact areas; 5) resolving resistance failure of pins from solder reflow contamination with proper cleaning and production procedures; and 6) resolving resistance failure of connector contacts by using such analytical techniques as laser mass spectroscopy and gas chromatograph mass spectroscopy to detect failure mode and develop cleaning procedures. 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