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Components, Hybrids, and Manufacturing Technology, IEEE Transactions on

Issue 2 • Date Jun 1989

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Displaying Results 1 - 19 of 19
  • The effects of dopants on the electrical resistivity in lead magnesium niobate multilayer ceramic capacitors

    Publication Year: 1989 , Page(s): 310 - 315
    Cited by:  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (460 KB)  

    Electrical resistivity studies were performed on multilayer ceramic capacitors (MLC) based on lead magnesium niobate and containing dopants of lead titanate, lead zinc niobate, and lead cobalt niobate. The results showed that lead titanate and/or lead zinc niobate had no effect on the electrical resistivity while lead cobalt niobate decreased the resistivity. In samples without lead cobalt niobate, the authors observed a conduction mechanism with an activation energy of ~1 eV, which is commonly observed in barium titanate based dielectrics. This is attributed to ionic conduction by the motion of oxygen vacancies. The increase in conductivity (or decrease in resistivity) resulting from the addition of lead cobalt niobate was attributed to electronic conduction through charge hopping among the cations. This conduction mechanism was characterized by an activation energy of ~0.5 eV. The transition between electronic and ionic conduction was a function of temperature and the concentration of lead cobalt niobate. Since the activation energy associated with the long-term failure was previously determined by a matrix of temperature and voltage accelerated-life tests to be ~1 eV, the authors conclude that conduction through charge hopping is not affecting the long-term reliability of these devices View full abstract»

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  • Theory of pseudoplastic screen inks in orifice printing

    Publication Year: 1989 , Page(s): 254 - 258
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    The theory of orifice printing with high-viscosity nonNewtonian screenable inks in thick-film hybrids is presented. Theoretical models describing various aspects of the printing have been found from fluid mechanics. The nature of pressure losses in printing has been investigated using the law of conservation of energy. The rheological suitability of screenable inks in the orifice printing has been studied. The study shows that the pseudoplastic property of the inks seems to be desired for the flow inside the tube, but not as much at the tip of the nozzle, where Newtonian rheology is more suitable View full abstract»

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  • Surface-mount attachment reliability of clip-leaded ceramic chip carriers on FR-4 circuit boards

    Publication Year: 1989 , Page(s): 284 - 296
    Cited by:  Papers (38)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1376 KB)  

    The reliability of the attachment of 100 I/O ceramic chip carriers (CCs) surface mounted to FR-4 epoxy/glass circuit boards using clip-leads has been investigated. Clip-leads, commercially available from two vendors, of significantly different designs were utilized. The accelerated tests involved the accurate reproduction of the thermal and physical conditions-internal cyclic power dissipation, external thermal cycling of forced air stream, thermal gradients, mounting hardware, etc.-encountered by the product in use. The test acceleration (by acceleration factors between 12 and 20 for mean time to failure) was accomplished with shorter dwell times at the temperature extremes, resulting in 96 accelerated fatigue cycles per day. The distinct difference in lead compliancy between the two clip-lead designs is clearly reflected in the results of the accelerated reliability tests. The Type-A `J-lead design' clip-lead (K=58 lb/in) CCs showed a median life to failure of 12000 cycles, while the Type-B `hinged S-bend design' clip-lead (K=7.5 lb/in) CCs exhibited no failures when the test was terminated at 100000 cycles. Failure mode analysis shows that all Type-A clip-lead solder joints have failed after 48000 accelerated cycles due to the CC/substrate expansion mismatch: at 100000 accelerated cycles a significant number of clip joints showed cracks due to the solder/ceramic CC material expansion differential View full abstract»

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  • Two novel additive processes to manufacture circuit boards: direct laser writing and direct electrostatic transfer and deposition

    Publication Year: 1989 , Page(s): 267 - 272
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (528 KB)  

    Two technologies are described to manufacture bare circuit boards. Both methods are dry processes and are additive by nature. The first technology is a process whereby circuit lines are written directly onto the substrate from a CAD/CAM database. There is no need for artwork to be generated with its inherent limitations. A circuit board is manufactured by applying a film of heat-sensitive adhesive to a substrate and depositing on the film a layer of conductive powder. The powder and film are then activated by laser radiation to define the circuitry. The excess powder is then removed and the substrate fired to cure or bond the powder to the substrate. The second technology is directed toward higher-volume production and requires the use of a master pattern. The fundamental principles involved are well understood in the photocopying field. The master pattern consists of a conductive base on which there is a pattern layer. The master pattern is also easily created by direct laser writing. The pattern layer receives an electrostatic charge. The master pattern is contacted by a developer containing a conductive material in the form of a powder or link and which transfers the conductive material to the pattern by electrostatic force. A substrate is then brought to a position closely adjacent to the master pattern and electrostatic force is used to deposit the particles from the pattern onto the substrate to accurately define the circuitry. The particles are then fixed by heating View full abstract»

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  • Electrical properties of K2O-doped Ba0.5Sr 0.5TiO3 ceramic humidity sensor

    Publication Year: 1989 , Page(s): 259 - 266
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    A ceramic humidity sensor using Ba0.5Sr0.5TiO3 doped with a few molar percent of potassium oxide was studied. It was characterized by long life, was reversible without repeated high-temperature thermal desorption processes, and conductance against relative humidity (RH) sensitivity, as high as four orders of magnitude, was found at low frequencies. This sensor showed a good exponential relationship between the conductance, RH, and temperature at low frequencies. The plots of the relative dielectric dispersion against RH showed that it had an apparent dielectric constant increase at low frequency as a result of the electrode and water molecular polarization effects. By complex impedance plots with a non-Debye capacitor concept, an equivalent circuit model was established which could well simulate all the electrical properties of the sensor in the range of 65-95% RH for all measured temperatures (25°C-85°C) and frequencies (5 Hz-13 MHz). In the measurement of this sensor, an inductance loop over the low RH (15% and 30%) and low frequencies (5 to 40 Hz) range was observed, which might be due to the desorption of water vapor at the electrode surface for reduction reactions View full abstract»

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  • Calculation of electrical parameters of a thin-film multichip package

    Publication Year: 1989 , Page(s): 303 - 309
    Cited by:  Papers (15)  |  Patents (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (564 KB)  

    The calculations of the electrical parameters of a thin-film multichip package are presented. It is shown that a commonly used 2-D device simulator, PISCES, can be used to compute the electrical parameters of the thin-film lines up to a frequency where the skin effect is important. For trapezoidal conductor cross-sections, it is shown that the maximum variations of self- and mutual (coupling) capacitances are within 10% of their corresponding rectangular values when the sidewall angle of the conductor is varied up to 30°, and the line cross-section area is kept constant. For the case when the conductor base is kept constant, the variation in mutual capacitance is found to be within 30% and that for self-capacitance is found to be within 12% when the sidewall angle is varied up to 30°. A simple R-L-C circuit is used to represent a three-conductor lossy transmission line system, and SPICE is used to analyze the responses in the time domain. A thin-film multichip package design is briefly outlined. A HP-8510 network analyzer is used to verify the simulation results View full abstract»

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  • Commutation with metal fiber brushes

    Publication Year: 1989 , Page(s): 246 - 253
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (656 KB)  

    For many years it has been widely held that metal fiber brushes cannot be used on commutators because the chopping action of commutator bars would cause fiber breakage and catastrophic wear, and current surges across adjoining bars would cause severe arcing and thus fast erosion. Recent experiments with copper fiber brushes in a protective argon atmosphere, using simulated commutation as well as running them as working brushes in an electromotor, contradict both of these assumptions. No fiber breakage was observed, arcing was only moderately stronger than with carbon brushes, and the total dimensionless wear rate in the motor was only about twice that on a polished copper rotor under otherwise comparable conditions View full abstract»

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  • The influence of composition and Cr particle size of Cu/Cr contacts on chopping current, contact resistance, and breakdown voltage in vacuum interrupters

    Publication Year: 1989 , Page(s): 273 - 283
    Cited by:  Papers (32)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (780 KB)  

    A range of commercially produced Cu/Cr materials with different compositions (25% to 75% Cu) and Cr particle sizes (up to 160 μm) has been investigated for their differences in chopping currents, contact resistance, breakdown voltage, contact erosion, and contact appearance. Test parameters have been chosen to reflect actual switching conditions. The properties of the Cu/Cr contact materials have been investigated after prestressing the electrodes with defined numbers of break arcs of 1 and 5 kA with alternating and unchanged polarity. It was found that the differences in properties of Cu75/Cr25 and Cu50/Cr50 contacts are minor as long as the same Cr particle size is used. Fine Cr particles increased the breakdown voltage and the rise in breakdown voltage after prestressing and the total erosion of contacts. While the mean chopping current values remained almost unaffected by fine Cr particles, the maximum values of chopping currents were deceased by using fine Cr particle sizes. Contact resistance and cathode surface structure after prestressing remained unaffected by a change in Cr particle size View full abstract»

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  • Multichip thin-film technology on silicon

    Publication Year: 1989 , Page(s): 185 - 194
    Cited by:  Papers (5)  |  Patents (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1112 KB)  

    A novel hybrid technique that uses pretested integrated circuits mounted into holes etched in a silicon wafer has been developed. The chips are interconnected with planar thin-film metallization. This approach achieves near-wafer-scale-integration density, while allowing the use of separately fabricated and tested devices. Test wafers with three monolithic chips and one chip mounted in a hole were fabricated as proof of concept. The key processes developed included fabrication of metallized and patterned wafers with etched holes, mounting of die in etched holes with planar topside topology, and deposition and patterning of the interlevel dielectric and metal links. An organic resin derived from benzocyclobutene was evaluated as the interlevel dielectric. Wafers were thermally cycled to evaluate the compatibility of materials and the process. No cracks or chip movement were observed after 50 cycles from -25°C to +85°C View full abstract»

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  • Vitreous carbon matrix for low-wear carbon/metal current collectors

    Publication Year: 1989 , Page(s): 224 - 228
    Cited by:  Patents (7)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (388 KB)  

    Friction, wear, and resistivity are reported for composite specimens made of copper fibers in vitreous or glassy carbon matrix. The resistivity and friction are shown to be comparable to reported values for typical copper graphite specimens, and the wear is shown to be exceptionally low. The experiments reported show that sound composites can be made by polymerization and pyrolysis of an organic material to form a glassy-carbon matrix around copper alloy fibers. This is a radically different process from the techniques of forming such composites from powder, or by pressure infusion of the metal into a graphitic body. Although the vitreous carbon is hard, it does not appear to act as an abrasive on a soft material. Qualitative observations in handling the composite material indicate that it is tough, and this is attributed to the energy absorption by the metal fibers View full abstract»

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  • Ultra-reliable packaging for silicon-on-silicon WSI

    Publication Year: 1989 , Page(s): 170 - 179
    Cited by:  Papers (10)  |  Patents (7)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1032 KB)  

    Silicon-on-silicon WSI (wafer-scale integration) packaging provides electronic equipment with significant reductions in size, weight, cost, and IC junction temperatures, together with significant increases in reliability and high-speed electrical performance. It combines semiconductor lithography techniques, printed-circuit multilayer techniques, and hybrid multichip module techniques. The silicon substrate has multiple layers of metallization and dielectric and services as a silicon circuit board. The author discusses the advantages of using silicon instead of conventional ceramic as the substrate materials and reviews the published status of this technology at other organizations. While conventional hybrid packages are successfully being used in early implementations to reduce size and weight, there exists an untapped potential for significant reliability improvements by switching to packages specifically designed for silicon substrates. Several potential packaging approaches are reviewed and results are presented for the fatigue life and thermal performance of silicon substrates View full abstract»

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  • Multi-layer thin-film substrates for multi-chip packaging

    Publication Year: 1989 , Page(s): 180 - 184
    Cited by:  Papers (6)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (548 KB)  

    It is commonly recognized that multiple chip module (MCM) packaging offers great advantages in system performance by virtue of the elimination of an entire level of interconnection. Multilayer thin-film module technologies for high-performance multiple chip packaging were developed and integrated. The technologies, which feature four copper layers, polyimide dielectric, controlled-impedance transmission lines, and solder bump assembly, were demonstrated on a variety of vehicles including, recently, a 4-kbyte RAM module operating at above 100-MHz clock frequency. The generic MCM substrate technology is described. The process can be designed to be compatible with a number of substrate materials as required for specific applications View full abstract»

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  • Tribological properties of edge card connector spring/tab interface

    Publication Year: 1989 , Page(s): 206 - 214
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (460 KB)  

    The influence of multilayer surface coatings on the tribological behavior of an edge-card connector was studied. The card tab had a multilayer structure consisting of a printed circuit board with overplated layers of copper, nickel, hard gold, and soft gold; the thickness of each was found to alter the frictional characteristics of the surface. Dry experimental data were found to agree with Finkin's theoretical model for solid film lubrication. As the thickness of soft gold increased for both dry and lubricated conditions, the coefficient of friction and wear increased. Surface roughness was observed to increase friction, and the increase of the soft gold-layer thickness had the tendency to increase surface roughness. It was found that the addition of a minimum layer of lubricant can lower the friction on the contact surface and reduce the influence of the layered surface coatings. The coefficient of friction remained relatively constant from thin film to flooded conditions. The difference in wear between dry and thin-film-lubricant conditions was minor View full abstract»

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  • Fretting damage in tin-plated aluminum and copper connectors

    Publication Year: 1989 , Page(s): 215 - 223
    Cited by:  Papers (7)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (976 KB)  

    A number of bolted-type tin-plated aluminum and copper connectors commonly used for distribution transformers were examined using scanning electron microscopy (SEM), energy-dispersive X-ray analysis (EDX), Auger electron spectroscopy (AES), X-ray analysis, and optical microscopy. In addition, the contact resistance of the connector contact zones was measured using a point probe. The connectors studied had been removed from service because of unsatisfactory performance under normal operating conditions as manifested either by overheating or instability. The results of the detailed examination show the presence of extensive fretting damage in the contacting surfaces. The fretting debris was composed mainly of tin oxide and oxidized base metal particles. Localized melting and wear of the tin plating down to the underlying substrate were also observed in some of the connectors examined View full abstract»

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  • Internal thermal resistance of a multi-chip packaging design for VLSI based systems

    Publication Year: 1989 , Page(s): 163 - 169
    Cited by:  Papers (23)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (632 KB)  

    A heat-transfer study is conducted for the steady-state internal thermal resistance of a multichip packaging technology for VLSI-based systems. This technology, which is known as advanced VLSI packaging (AVP), has chips flip-chip soldered and interconnected on a silicon substrate. AVP's thermal management approach is to dissipate chip power through the silicon substrate to a heat sink or other packaging levels. The authors found a need to control the chip-to-substrate interface; therefore, they use a three-dimensional heat conduction analysis to characterize this interface. They simulate thermal performance of typical AVP assemblies affected by thermal vias, solder bump heights, high-power I O drivers, and chip sizes. The authors also analyze and measure the internal resistances of an experimental package consisting of three WE32100 chips. These resistances are predicted as 3.7, 4.7, and 5.0°C/W, respectively; they are confirmed by the experimental data. The authors demonstrate the low thermal resistance achieved: 3.0°C/W for a 1-cm square chip and 10°C/W for a 0.25-cm square chip. They also provide their insight into the roles of different conduction paths involved View full abstract»

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  • A thick-film coplanar probe for time domain measurements

    Publication Year: 1989 , Page(s): 297 - 302
    Cited by:  Papers (4)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (412 KB)  

    The design, fabrication, and characterization of coplanar probes are presented. The probes are designed to work as launchers/adapters for performing wideband microwave measurements on planar geometry lines. The probes are made in the form of tapered coplanar lines, fabricated on alumina, teflon, and teflon-ceramic composite substrates. The time-domain reflectometry (TDR) technique was used to characterize the probes. Equivalent networks for the probes are developed using the modified transient circuit analysis program (MTCAP) by fitting a simulated TDR response to the measured TDR waveform and using a circuit simulation program (e.g. SPICE) to analyze the obtained equivalent network. The equivalent network of the probe thus obtained can then be used to de-embed the probe's contribution to a wideband microwave measurement, and thereby reducing measurement errors View full abstract»

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  • Techniques for fabrication of wafer scale interconnections in multichip packages

    Publication Year: 1989 , Page(s): 195 - 205
    Cited by:  Papers (7)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1444 KB)  

    Wafer-scale hybrid packaging (WSHP), multichip modules (MCM), high-density interconnect (HDI), thin-film multilayer (TFML) packaging, and advanced VLSI packaging (AVP) are different terms used to refer to an approach for fabricating chip-to-chip connections using semiconductor technology. However, persistent yield problems have made successful scale-up of the technology to full-sized, system-oriented wafer-scale packages difficult. Most of these problems can be traced to stress resulting from the different thermal properties of the various materials used in fabrication and the high-temperature processing steps involved. The authors explore use of focused-electron-beam and ion-beam repair strategies for coping with residual faults in a model high-yield liftoff process for fabricating wafer-scale interconnections in multichip packages View full abstract»

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  • Electrically and frictionally derived mound temperatures in carbon graphite brushes

    Publication Year: 1989 , Page(s): 229 - 236
    Cited by:  Papers (8)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (528 KB)  

    Thermal mounding in brushes can cause concentrations of electrical and mechanical loading. Joule heating due to current constriction and plastic work dissipation associated with sliding friction give rise to very intense subsurface heat sources local to the thermal mound. Coupled with the nonlinear material thermal properties of brush grade carbon graphites, temperatures of thousands of degrees Celsius can result. Numerical and analytical simulations of mound temperatures are presented as the mound evolves from cold to hot. The temperature field about a thermal mound in an electrical brush is estimated using a heat conduction equation with frictional and electrical internal heat sources. Properties vary realistically with temperature, and variations due to changes in current, sliding speed, and other factors are also presented View full abstract»

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  • On the two modes of operation of monolithic Ag-C brushes

    Publication Year: 1989 , Page(s): 237 - 245
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (980 KB)  

    The previously observed transition from low-temperature (mode I) to high-temperature (mode II) behavior in silver-graphite brushes can be explained either by changes of constriction resistance through the temperature dependence of electrical resistivity and hardness at negligible film resistivity and one to three contact spots, or by loss of graphite lubrication within the interfacial film. These two interpretations were tested by controlling the contact spot temperature: (1) by heating in an oven and (2) by local heat input through friction. Correlated studies of contact resistance, friction, wear rate, wear chip size, wear chip microstructure, and calculations of contact spot temperatures favor the second hypothesis. Micrographic evidence suggests that this occurs through desorption of water vapor from the graphite. It is found that primary wear particles form due to the wedge mechanism and by cutting by graphite fragments steeply inclined to the interface. Silver fragments may consolidate into secondary wear particles 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