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

Issue 3 • Date Sep 1997

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Displaying Results 1 - 13 of 13
  • 1/f noise in bismuth ruthenate based thick-film resistors

    Publication Year: 1997 , Page(s): 355 - 360
    Cited by:  Papers (5)  |  Patents (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (144 KB)  

    We report measurements of 1/f noise in bismuth ruthenate (Bi2 Ru2O7) thick-film resistors in the frequency range of 1 Hz to 40 kHz including the dependence of the noise on the bias current, resistance in the range 1 kΩ to 400 kΩ and laser trimming effects. The noise spectra show that the magnitude of the noise parameterized by the relative noise index parameter C has the approximate dependence given by C=3×10-15 (Rsns)0.6, where ns is the aspect ratio and Rs is the sheet resistance. Technologically this is an important result since it allows the prediction of the approximate level of noise for any resistor made from the BIROX series compounds from the ink resistivity and the dimensions of the resistor. The link between the noise magnitude and noise models is examined View full abstract»

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  • Three-dimensional visualization of multilayered assemblies using X-ray laminography

    Publication Year: 1997 , Page(s): 361 - 366
    Cited by:  Papers (8)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (100 KB)  

    The imaging technique of X-ray laminography is useful for studying defects in ball grid array, gull-wing and J-lead solder joints. In this process, X-ray images are made to depict cross-sectional planes in multilayered assemblies. It is desirable to be able to create a three-dimensional (3-D) visualization of the assembly by stacking a succession of laminographic cross sections of neighboring planes. In the past this has not been possible for highly layered assemblies because the images contain inherent blurring, which causes the signal-to noise ratio for a 3-D reconstruction to be extremely poor. This paper explains a technique for reconstructing accurate 3-D visualizations of assemblies based upon a small number of laminographic images. Experimental results are described that show that this technique is sensitive to small defects in metallic objects such as ball grid array (BGA) joints View full abstract»

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  • Adhesion strength and microstructural evaluation in electroless Ni-P metallized AlN substrate

    Publication Year: 1997 , Page(s): 342 - 354
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (444 KB)  

    The adhesion strength of the electroless Ni (EN)-plated AlN substrates is studied through investigation of the microstructural morphologies at the AlN-EN interfaces. Etching sites around the Al-Y-O compounds on the etched AlN substrate provide the anchor acceptors for interlocking the EN film to achieve a high adhesion strength. Separation of the EN film from the AlN substrate under the action of force leaves the fracture cracks propagating along the AlN/EN interface, cutting through the anchors and making the fragmental EN films around the etching sites reside on the AlN fracture surface. However, the polished AlN substrate lacks the interlocking sites and fails to obstruct the cracks propagating along the AlN/EN interface, and thus results in a poor adhesion strength. An appropriate adhesion strength of 13.7 MPa with a small standard deviation (±2.3 MPa) can be obtained for the previously etched and 10 μm thick EN-plated AlN substrate View full abstract»

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  • Electronic Components Obsolescence

    Publication Year: 1997 , Page(s): 368 - 371
    Cited by:  Papers (4)
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  • Moisture absorption and desorption predictions for plastic ball grid array packages

    Publication Year: 1997 , Page(s): 274 - 279
    Cited by:  Papers (61)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (160 KB)  

    Plastic electronic packages are known to absorb moisture when exposed to humid ambient conditions during storage in tape and reel in the factory. Reliability becomes a concern when packages are exposed to a humid environment for a prolonged time and then processed through a reflow oven. Thermo-mechanical and moisture induced interfacial stresses generated between the die attach and die may lead to die delamination and package cracking. Current package level moisture evaluation methods are based on experimental weight gain measurements and visual inspection after reflow for cracking or delamination. This study presents a finite element analysis (FEA) simulation of the moisture weight gain or loss in plastic ball grid array (PBGA) packages as a function of time, including the effects of package geometry and material selection. Experimental weight gain and bake-out data for a 68 I/O PBGA package are shown to closely match FEA model predictions. Diffusivity and solubility property data for common packaging materials are given as a function of temperature from 23 to 210°C. Solder pot dip tests performed at 230°C indicate that popcorn failures result when the moisture concentration in the die attach region exceeds 0.0048 g/cm3 for the specific package tested View full abstract»

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  • Modeling thermally induced viscoplastic deformation and low cycle fatigue of CBGA solder joints in a surface mount package

    Publication Year: 1997 , Page(s): 280 - 285
    Cited by:  Papers (12)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (160 KB)  

    A nonlinear finite element model was used to analyze the thermally induced viscoplastic deformation and low cycle fatigue behavior of the lead-tin (Pb-Sn) solder joints in a 32 mm ceramic ball grid array (CBGA) surface mount package. The effects of the cyclic frequency, hold (dwell) time, and temperature ramp rate on the response of the viscoplastic (creep and plastic) deformation for the CBGA solder joints were studied by applying four different low cycle thermal fatigue loads to the package. The modeling results show that the maximum viscoplastic strains occur in and around the edge CBGA solder joint. The cyclic creep strain (ratchetting) is very significant and dominates the constituent of the accumulated viscoplastic strain. The equivalent plastic strain increases with the increase of cyclic frequency and ramp rate, and decreases as the hold time increases. However, the equivalent creep strain decreases with the increase of cyclic frequency and ramp rate, but increases as the hold time increases. In the solder joint, the Pb37-Sn63 solder paste has approximately 2× larger equivalent plastic strains, and 10× larger equivalent creep strains than that in the Pb90-Sn10 solder ball during thermal cycling View full abstract»

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  • A high heat flux IGBT micro exchanger setup

    Publication Year: 1997 , Page(s): 334 - 341
    Cited by:  Papers (19)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (196 KB)  

    Much progress has been made over the past few years in the design of power electronic components leading to increasing development of IGBT transistors. Now IGBT's can dissipate power densities higher than 400 W/cm2 and the thermal environment has become a major factor in their behavior. The aim of this paper is to demonstrate the high performance of a silicon microchannel setup. First, a thermal study enables the theoretical behavior of the setup to be analyzed. Then an optimization method based on genetic algorithms allows us to determine the best sizes for the microchannels. Finally, the theoretical results are compared with experimental measurements View full abstract»

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  • Finite element analysis of PWB warpage due to the solder masking process

    Publication Year: 1997 , Page(s): 295 - 306
    Cited by:  Papers (13)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (264 KB)  

    Researchers have begun to examine the various manufacturing processes that a printed wiring board (PWB) undergoes during its production, such as lamination, solder masking, and soldering process to determine their impact on board warpage. The goal of this paper is to determine effects of the solder masking process on the PWB warpage. Finite element analysis was used to study the effects of the solder masking process, in particular the curtain coating and curing processes on PWB warpage of four different board designs. These analyses have aided development of general guidelines that should be observed when selecting solder masking material View full abstract»

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  • Fatigue-strength prediction of microelectronics solder joints under thermal cyclic loading

    Publication Year: 1997 , Page(s): 266 - 273
    Cited by:  Papers (7)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (196 KB)  

    The stress-strain analyses for the solder joints in a thin single outline package (TSOP), a ball grid array (BGA) assembly, and a leadless ceramic chip carrier (LCCC) are carried out to investigate the plastic-creep behavior, and stress relaxation behavior due to the temperature cycling or isothermal cyclic loading. The temperature dependence of plastic behavior (yield stress) and creep behavior (creep properties) are taken into consideration in all numerical analyses. The results of finite element analysis (FEA) show that in an accelerated temperature cycling test, long high-temperature and low-temperature dwell times do not contribute to the increase of the cyclic inelastic equivalent strain range in solder joints (although the creep behavior occurring during the dwell times in an operating condition is important enough to be taken into consideration for estimating the fatigue life of solder joints). Based upon the results of the strain analyses, some efficient testing processes of temperature cycling and isothermal fatigue tests for the microelectronic solder joints are proposed, and the cycling tests are carried out. The experimental results show a good agreement with the analytic results View full abstract»

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  • Thermal phenomena in compact electronic enclosures: a numerical study

    Publication Year: 1997 , Page(s): 286 - 294
    Cited by:  Papers (8)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (260 KB)  

    Thermal phenomena in passively cooled compact electronic enclosures is numerically investigated in this study. Coupled heat transfer and fluid flow is considered. Conduction in the components and enclosure walls, and convection in the fluid is accounted for in the model. The governing steady-state nondimensional equations with appropriate boundary conditions are solved using finite volume formulation. Uniform energy generation is assumed in the components. Computations are performed for a range of power dissipation levels, component thermophysical properties, component configurations, internal enclosure volume available for natural convection in an enclosure with or without vents. Baseline computations are performed for an enclosure with a centrally located component. Lower maximum component temperatures are produced in vented enclosures for low power dissipation, high component thermal conductivity and continuous component configuration. The results of this parametric study are used to develop an empirical correlation for the maximum component temperature in the enclosure View full abstract»

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  • Finite element analysis of PWB warpage due to cured solder mask-sensitivity analysis

    Publication Year: 1997 , Page(s): 307 - 316
    Cited by:  Papers (7)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (268 KB)  

    This paper describes the impact of different types of cured solder mask and mask thicknesses on printed wiring board (PWB) warpage. Finite element analysis (FEA) was used to study the sensitivity of board warpage to changes in the mask material properties (different types of solder mask), and to variations in mask thickness. The sensitivity analysis of the influence of cured solder mask and variations in mask thickness on PWB warpage are the focus of this paper. The study reported in this paper was carried out with four different board designs, and the results are presented here. The results of these analyses have resulted in general guidelines which should be observed when selecting masking materials View full abstract»

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  • A study on thermal-stress-reliability of Si-based PLC substrate

    Publication Year: 1997 , Page(s): 327 - 333
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (152 KB)  

    Planar lightwave technology is rapidly advancing and promises excellent performance as economical opto-electro-devices. To confirm its feasibility, it is very important to estimate its mechanical reliability especially against the thermal stresses caused by the difference of the thermal expansion coefficients of Silicon and silica glass. This paper examines the thermal strain and stress distribution on silicon-based Planar-Lightwave-Circuits (PLC) substrates and the stress concentration on silicon terrace structures prepared for mounting active optical devices. Experimental data on the fracture strength of silicon obtained by three-point-bending tests are given. Finally, the thermal-stress-reliability of PLC substrates based on probabilistic analysis is calculated and it is confirmed that the PLC substrate, even its present form, is reliable enough for a new family of optical components View full abstract»

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  • Coffin-Manson fatigue model of underfilled flip-chips

    Publication Year: 1997 , Page(s): 317 - 326
    Cited by:  Papers (31)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (276 KB)  

    The fatigue life of an underfilled flip-chip package has been evaluated using the Coffin-Manson relation and finite element modeling (FEM)-computed solder shear strain for typical flip-chip structures. In the course of this effort, numerical simulations were performed for underfill materials of varying thermo-structural properties, two chip sizes, and two solder bump heights. The results were used to examine the parametric sensitivity of the thermal strain in the solder joints and the axial, as well as shear stress in the underfill material. The predicted improvement in the number of cycles-to-failure of the underfilled flip-chip was found to agree with empirical observation. However, the maximum improvement achievable by underfilling was found to be limited by the adhesion strength of the underfill material 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