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Components, Packaging, and Manufacturing Technology, Part A, IEEE Transactions on

Issue 3 • Date Sept. 1998

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Displaying Results 1 - 17 of 17
  • Foreword thermal investigations of ICs and microstructures (THERMINIC)

    Page(s): 397 - 398
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    Freely Available from IEEE
  • Thermal parameters measurement method of electronics materials

    Page(s): 424 - 433
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    The fast and precise photoacoustic methods of determination of all thermal parameters and additionally the optical absorption coefficient in the case of nonopaque solid state materials used in the electronic industry are presented. The procedures that allow one to determine the thermal diffusivity, thermal effusivity, thermal conductivity and specific heat of any material are presented. Both methods (for opaque and nonopaque material) are based on a comparison of thermal impedance frequency phase and amplitude characteristics of the samples with pattern characteristics. In the case of opaque materials they are the functions of thermal material parameters and the frequency of modulation. For nonopaque materials pattern characteristics are functions of universal and absolute arguments. Experimental results illustrating the procedures are presented and discussed for the following materials: silicon, copper, brass, and epoxy molding compound Hysol MG-40F-R View full abstract»

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  • Conductive adhesives for high-frequency applications

    Page(s): 469 - 477
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    In this paper, we present results from measurements and simulations on epoxy-based anisotropic electrically conductive adhesive joints (ACA). We have studied two different types of connections, flip-chip bonded Si test chip and a simple transmission line gap bridged by a copper foil. The test chips were mounted on three different substrates, a rigid FR-4 board, a flexible board and a high-frequency teflon-based duroid substrate. Equivalent electrical models are discussed based on physical considerations and the parameters were then fitted to measurement data in the high-frequency CAD tool HP MDS, A HP8510 network analyzer was used to measure S-parameters on rigid FR-4 and flexible boards in the frequency range 500 MHz-8 GHz for both flip-chips and bridges. For the duroid mounted flip-chips and bridges, the frequency range was 1-30 GHz. The microstructures of the ACAs were studied by cross-sectioning and then using scanning electron microscopy (SEM). For low frequency applications (500 MHz-8 GHz) the results indicated that the ACA flip-chip joint and the bridge joint mounted on the FR-4 board or flexible board can be used. For high-frequency applications (1-30 GHz) the results showed that the ACA flip-chip joint and the bridge joint mounted on the duroid substrate can be used. For duroid and FR-4 mounted flipchip joints and bridge joints ACA has proved to be as good as or even better than the solder joint, for FR-4 in the frequency range 45 MHz-2 GHz and for the duroid substrate 1-30 GHz View full abstract»

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  • Radiative properties of SIMOX

    Page(s): 441 - 449
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    The first experimental results of the temperature dependent radiative properties of separation by implantation of oxygen (SIMOX) wafers, in the literature, have been reported in this study. These measurements have been performed in the temperature range of 17 to 800°C and wavelength range of 0.8 to 20 μm using a spectral emissometer. A modeling approach based on Multi-Rad, a matrix method of representing multi-layers, has been adopted to interpret the experimental data. Operating ranges of wavelength for pyrometry have been suggested for a reliable monitoring of temperature for processing SIMOX wafers View full abstract»

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  • Propagation analysis for thermal modeling

    Page(s): 418 - 423
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    Propagation analysis was originally developed as a tool for the analysis of the transmission line matrix (TLM) numerical technique and its relationship to other numerical methods for heat-flow. It provides a useful alternative to the conventional frequency-domain methods for analyzing parabolic differential equations. This paper outlines the details of the technique and demonstrates the manner in which it provides information about attenuation and phase in what is essentially lossy wave propagation View full abstract»

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  • Photothermal examination of adhesion in semiconductor devices

    Page(s): 434 - 440
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    The adhesion quality influence on the phase and amplitude characteristics of the thermal transmittance in the layered structures is determined theoretically and experimentally. The photothermal pictures of ultrasonic bonds, the galvanized lead frame, and the semiconductor chips soldered to the lead frame are presented and discussed View full abstract»

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  • High frequency measurements and simulations on wire-bonded modules on the sequential build-up boards (SBU's)

    Page(s): 478 - 491
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    This paper presents the results from high-frequency measurements and simulations on sequential build-up boards (SBU's). A high-frequency test pattern was designed in order to investigate the high-frequency properties of SBU's. The SBU boards were supplied by four different manufacturers. The test boards contained patterns for crosstalk, impedance matching, stray capacitance, and wire-bonding. The test boards consisted of doublesided FR-4 core with two built-up layers on each side. However, the high-frequency test board was only on one side of the core. The test patterns were located in layer five and layer six. Two different line spacings between signal track and victim track, 50 and 100 μm, were considered. The S-parameters were measured on a network analyzer in the frequency range 45 MHz-10 GHz. In the time domain experiment, the near-end and the far-end response in the victim track was measured. All the simulations were carried out, using the simulation programs P-Spice, HP MDS, and a two-dimensional (2-D) finite difference program. Impedance measurements and simulations were performed in layer five and six with conductor widths corresponding to characteristic impedances of 50 and 55 Ω. The line widths ranged from 40 to 65 μm in layer five and 150 to 200 μm in layer six. Reference tracks were designed in order to estimate conductor and dielectric losses View full abstract»

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  • Packaging factors affecting the fatigue life of power transistor die bonds

    Page(s): 459 - 468
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    This paper presents an overview of die bond fatigue and a study of packaging and assembly factors and their influence on power transistor cyclic life. Power transistors with soft solder die bonds will fail by catastrophic failure, under cyclic conditions, as fatigue cracks develop and propagate through the die bond. Susceptibility to catastrophic failure increases over the life of the device, as crack growth through the die bond destroys the capability of the device to transfer heat. Power cycling tests followed by failure analysis show that die bond thickness has the most significant effect on catastrophic failure, followed by die bond thickness variation. Analysis shows, that for a given device, the die bond is not uniform and that the nonuniformity or die tilt (ratio of average to minimum thickness) influences device life by affecting strain concentration and crack growth. Oxygen content in the package, also influences device life to a lesser extent, as indicated by a statistical analysis of residual gas analysis results compared to cyclic life. This can be explained by crack closure effects during the development of die bond fatigue cracks. These findings further the understanding of die bond physics of failure and underscore the importance of optimizing die bond thickness in design and limiting variations and oxygen content in hermetic metal packages, during device manufacturing and assembly View full abstract»

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  • A novel lightweight microwave packaging technology

    Page(s): 515 - 520
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    Spray-formed alloys of silicon-aluminum have been used as the basis for a new microwave packaging technology for aerospace applications, taking advantage of the low thermal expansivity, high thermal conductivity and unusually low density of these materials. These high-silicon Si-Al alloys are relatively easy to machine to tight tolerances using standard workshop facilities and they can be electroplated with relative ease. Demonstrator microwave amplifier modules designed for space application have been successfully produced and tested. The packages comprise kovar side-walls supplied with appropriate RF and DC feedthroughs, which are bonded to the Si-Al base by diffusion soldering. This package configuration provides rigid bases for the circuitry and a weight saving of typically 30% over all-kovar packages View full abstract»

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  • Development of large-area BaTi03 ceramics with optimized depletion regions as dielectrics for planar power electronics

    Page(s): 492 - 499
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    High-voltage (500 V) barium titanate (BaTiO3) ceramics are under development as compact high-permittivity dielectrics for planar structures in integrated power-electronic converters. Dielectric requirements include a high permittivity for meeting the dimensional constraints in converters, a high power-handling capability, low loss, and flat permittivity and tanδ frequency responses up to 1 MHz. Dopant materials examined here focused on fine powders of Al203 and Al added during the sintering process. Best results were obtained by diffusion of externally-placed Al during the sintering cycle, with BaTiO3 permittivities εr ~1000, and loss tangents tanδ <~4% over 1 kHz to 1 MHz. This paper describes fabrication and doping methods aimed at achieving such specifications. Electrical C-V testing up to 500 V on specimens of thickness 0.5-0.7 mm (with E-field intensities up to 106 V/m) was carried out using l-kHz bridge measurements, as well as in a power-electronic chopper circuit employing a BJT switch, and operating up to 500 V with pulse widths ~25 μs and repetition rates ~4 kHz View full abstract»

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  • Adaptive modeling of the transients of submicron integrated circuits [monolithic microwave devices]

    Page(s): 412 - 417
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    The development and application of a transient, multiple-grid solution system are shown to lead to a dramatic decrease in the computational time requirements for complex three-dimensional (3-D) thermal problems. A multiple-grid solution technique is presented which successfully handles multiple materials and temperature-dependent thermal conductivity. The meshing technique is adaptive in both space and time, is independent of the initial grid size, and allows the user to specify the desired accuracy requirements. Based on the steady-state solution of a given problem and the predicted error fields, a template of nest levels is identified which resolves the physics everywhere in the computational domain to within the specified accuracy criterion. The nesting template is then used to solve the transient problem over the nested grids with automatically determined adaptive time steps. The application of this spatially and temporally adaptive system reduces the computational time requirements by two orders of magnitude over conventional transient methods. Consequently, concurrent electrical and thermal design of high-performance integrated circuits becomes, for the first time, both possible and practical View full abstract»

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  • Characterization of self-heating in advanced VLSI interconnect lines based on thermal finite element simulation

    Page(s): 406 - 411
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    In this paper, self-heating of interconnects has been shown to affect the lifetime of next generation integrated circuits significantly more severely than today's. The paper proves the necessity for extending the system of design rules, proposes a thermal design rule, and presents an efficient and quantitatively accurate thermal simulator as tool for the design process View full abstract»

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  • Getting the quality and reliability terminology straight

    Page(s): 521 - 523
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    Failures are often due to a complex set of stochastic interactions between the loads that act on a product and the various elements (design, materials, components, software, fabrication) that comprise the product. Preventing failures by understanding and improving product quality and reliability is sometimes hindered by the misapplication of important terminology. The intent of this article is to reduce miscommunications by defining some of the key vocabulary used in the field of quality and reliability, and by explaining their misuse and appropriate use View full abstract»

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  • Effect of surface reactivity of lubricants on the properties of aluminum electrical contacts

    Page(s): 500 - 505
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    Lubricants are used in electrical contacts to minimize friction and mechanical wear and protect electrical interfaces against corrosion, This paper provides an example of the importance of differentiating between the lubrication and “electrical-contact protection” properties of lubricants. The paper reports on the frictional properties and the effect on contact resistance of stearic acid boundary films on aluminum. Stearic acid is an effective lubricant for aluminum because the long-chained acid molecules are chemically attached to the native aluminum oxide surface film. In an electrical contact, mechanical disruption of this native oxide film during sliding exposes the underlying aluminum metal to the stearic acid. The ensuing chemical reaction of the acid with the exposed metal leads to chemical breakdown of the lubricant and immediate surface oxidation of the aluminum. This reaction engenders a large increase in contact resistance. These observations provide unambiguous evidence that stearic acid is unacceptable as a lubricant for aluminum electrical contacts, although it is effective as a conventional lubricant for aluminum View full abstract»

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  • Precision measurement and mapping of die-attach thermal resistance

    Page(s): 506 - 514
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    The thermal resistance of the attachment between a die and its carrier contributes strongly to the total temperature rise in an electronic system. The die attach resistance often differs substantially from the value predicted using the bulk thermal conductivity of the attachment material because of partial voiding and delamination. These defects can be introduced during the attachment process or during subsequent exposure to humidity or temperature fluctuations. This manuscript develops a technique for precisely measuring the spatially-averaged die-attach thermal resistance and for mapping spatial variations of the resistance in the plane of the die. The spatially-averaged resistance measurements use transient electrical heating and thermometry at frequencies up to 1 kHz to achieve a value of the uncertainty near 10-6 m2K/W, which is a substantial improvement over existing steady-state methods. Spatial variations are captured using scanning laser-reflectance thermometry and a deconvolution method detailed here. The data in this manuscript show the impact of the adhesive material, the adhesive thickness, and the attachment pressure on the thermal resistance, as well as the spatial variation of the resistance resulting from incomplete contact View full abstract»

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  • A thermal benchmark chip: design and applications

    Page(s): 399 - 405
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    A 1.2-μm complementary metal-oxide-semiconductor (CMOS) thermal benchmark chip has been designed, fabricated and tested. The chip is suitable to support various steady-state and transient measurements, e.g., heating and cooling curves, in-chip thermal couplings. It facilitates the calibration of various chip temperature mapping equipment. Besides the description of the chip design experimental results are presented in order to demonstrate the wide usability of this measurement supporting tool View full abstract»

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  • High performance no-flow underfills for low-cost flip-chip applications: material characterization

    Page(s): 450 - 458
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    Underfill encapsulant is critical to the reliability of the flip-chip solder joint interconnects. Novel no-flow underfill encapsulant is an attractive flip-chip encapsulant due to the simplification of the no-flow underfilling process. To develop the no-flow underfill material suitable for the no-flow underfilling process of flip-chip solder joint interconnects, we have studied and developed a series of metal chelate latent catalysts for the no-flow underfill formulation. The latent catalyst has minimal reaction with the epoxy resin (cycloaliphatic type epoxy) and the crosslinker (or hardener) at the low temperature (<180°C) prior to the solder reflow and then rapid reaction takes place to form the low-cost high performance underfills. The effects of the concentration of the hardener and catalyst on the curing profile and physical properties of the cured formulations were studied. The kinetics and exothermic heat of the curing reactions of these formulations were investigated by differential scanning calorimetry (DSC). Glass transition temperature (Tg) and thermal coefficient of expansion (TCE) of these cured resins were investigated by thermo-mechanical analyzer (TMA). Storage moduli (E',E") and crosslinking density of the cured formulations were measured by dynamic-mechanical analyzer (TMA). Weight loss of these formulations during curing was investigated by thermo-gravimetric analyzer (TGA). Additionally, some comparison results of our successful novel generic underfills with the current commercial experimental no-flow underfills are reported View full abstract»

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Aims & Scope

This Transaction ceased production in 1998. The current publication is titled IEEE Transactions on Components, Packaging, and Manufacturing Technology.

Full Aims & Scope