By Topic

Components and Packaging Technologies, IEEE Transactions on

Issue 2 • Date June 2008

Filter Results

Displaying Results 1 - 25 of 43
  • Table of contents

    Publication Year: 2008 , Page(s): C1
    Save to Project icon | Request Permissions | PDF file iconPDF (253 KB)  
    Freely Available from IEEE
  • IEEE Transactions on Components and Packaging Technologies publication information

    Publication Year: 2008 , Page(s): C2
    Save to Project icon | Request Permissions | PDF file iconPDF (43 KB)  
    Freely Available from IEEE
  • Table of contents

    Publication Year: 2008 , Page(s): 241 - 242
    Save to Project icon | Request Permissions | PDF file iconPDF (53 KB)  
    Freely Available from IEEE
  • Foreword

    Publication Year: 2008 , Page(s): 243 - 244
    Save to Project icon | Request Permissions | PDF file iconPDF (383 KB) |  | HTML iconHTML  
    Freely Available from IEEE
  • An Effective Method for Calculation of Corner Stresses With Applications to Plastic IC Packages

    Publication Year: 2008 , Page(s): 245 - 251
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1024 KB) |  | HTML iconHTML  

    Plastic integrated circuit (IC) packages are usually composite components made of multiple bonded materials with different mechanical and thermal properties. High stresses often occur at corners between different components within the packages where discontinuities of geometry or material properties are present. Delaminations usually initiate from these corners when packages undergo adverse thermal or moisture environments. Hence, in order to prevent delaminations from occurring and to improve package reliability performance, it is crucial to accurately and efficiently evaluate the stresses at corners within the package. However, with conventional finite element methods, it is always a challenge to give an accurate description of the stresses at the corners since these corners represent stress singularity points. In this paper, an effective method is developed to precisely evaluate the stresses in the vicinity of internal corners within the packages. A new variable-order singular boundary element is constructed with a built-in accurate description of the stresses at the corner. This method is versatile for solving general corner problems involving wedges, two-material and three-material corners and interfacial cracks that are common in the IC packages. This method is verified by solving a bimaterial interface crack problem with known solution. Comparisons are made with other conventional methods such as displacement-based quarter-point singular elements and normal quadratic elements, on the calculation of interfacial stress intensity factors. Results show that the new method has significant advantages in giving more accurate results with much less computational resources needed. The new method is applied to a typical plastic IC package with multiple internal corners and interface cracks. The possible failure sites and failure modes within the package are predicted and the results agree well with package evaluations done in the industry. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Interfacial Delamination Mechanisms During Soldering Reflow With Moisture Preconditioning

    Publication Year: 2008 , Page(s): 252 - 259
    Cited by:  Papers (21)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (984 KB) |  | HTML iconHTML  

    This paper first examines the commonly-used thermal-moisture analogy approach in thermal-moisture analogy approach. We conclude that such an analogy using a normalized concentration approach does not exist in the case of soldering reflow, when the solubility of each diffusing material varies with temperature or the saturated moisture concentration is not a constant over an entire range of reflow temperatures. The whole field vapor pressure distribution of a flip chip BGA package at reflow is obtained based on a multiscale vapor pressure model. Results reveal that moisture diffusion and vapor pressure have different distributions and are not proportional. The vapor pressure in the package saturates much faster than the moisture diffusion during reflow. This implies that the vapor pressure reaches the saturated pressure level in an early stage of moisture absorption, even the package is far from moisture saturated. However, the interfacial adhesion degrades continuously with moisture absorption. Therefore, the package moisture sensitivity performance will largely reply on the adhesion strength at elevated temperature with moisture. A specially designed experiment with a selection of six different underfills for flip chip packages was conducted. Results confirm that there is no correlation between moisture absorption and the subsequent interface delamination at reflow. The adhesion at high temperature with moisture is the only key modulator that correlates well with test data. Such a parameter is a comprehensive indicator, which includes the effects of thermal mismatch, vapor pressure, temperature and moisture. In this paper, a micromechanics based mechanism analysis on interfacial delamination is also presented. With the implementation of interface properties into the model study, it shows that the critical stress, which results in the unstable void growth and delamination at interface, is significantly reduced when the effect of moisture on debonding is considered. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Driving Mechanisms of Delamination Related Reliability Problems in Exposed Pad Packages

    Publication Year: 2008 , Page(s): 260 - 268
    Cited by:  Papers (8)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1317 KB) |  | HTML iconHTML  

    Exposed pad packages were introduced in the late 1980s and early 1990s because of their excellent thermal and electrical performance. Despite these advantages, the exposed pad packages experience a lot of thermo-hygro-mechanical related reliability problems during qualification and testing. Examples are die lift, which occurs predominantly after moisture sensitivity level conditions, and die-attach to leadframe delamination leading to downbond stitch breaks during temperature cycling. In this chapter, nonlinear finite element (FE) models using fracture mechanics based J-integral calculations are used to assess the reliability problems of the exposed pad package family. Using the parametric FE models any geometrical and material effects can be explored to their impact on the occurrence diepad delamination, and dielift. For instance the impact of diepad size is found to be of much less importance as the impact of die thickness is. Using the fracture mechanics approach, the starting location for the delamination from thermo-hygro-mechanical point of view is deducted. The results indicate that when diepad delamination is present, cracks are likely to grow beneath the die and dielift will occur. The interaction between dielift and other failure modes, such as lifted ball bonds, are not found to be very significant. The FE models are combined with simulation-based optimization methods to deduct design guidelines for optimal reliability of the exposed pad family. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Effect of Non-Uniform Moisture Distribution on the Hygroscopic Swelling Coefficient

    Publication Year: 2008 , Page(s): 269 - 276
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1037 KB) |  | HTML iconHTML  

    The coefficient of hygroscopic swelling is a material property used to measure the volumetric change with moisture absorption under given humidity and temperature conditions. Current hygroscopic swelling characterization techniques use an averaged approach based on the averaged moisture content. However, the moisture distribution is not uniform across the test specimen during measurement. This introduces analysis errors in determining the material property. In this paper, an exact analytical solution was derived to obtain the accurate coefficient of hygroscopic swelling, with the consideration of 3-D moisture diffusion across the specimen. The correlation between the locally defined and the averaged coefficient of hygroscopic swelling was obtained analytically. The results showed that the coefficient of hygroscopic swelling obtained based on the previous method using the averaged approach may overestimate the property up to 250%. The methodology and formulation developed in this paper was then applied to analyze a set of existing experimental data, and results were compared to the current approach. This paper also investigated the reliability of a flip chip ball grid array package under high accelerated stress test condition (120degC/100%RH). Finite element analysis simulation results revealed the significance of contribution of hygroscopic swelling induced tensile stresses under bump region. The finite element results gave an insight of the failure mechanism associated with moisture absorption. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Influence of Nonuniform Initial Porosity Distribution on Adhesive Failure in Electronic Packages

    Publication Year: 2008 , Page(s): 277 - 284
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1259 KB) |  | HTML iconHTML  

    Adhesives in electronic packages contain numerous pores and cavities of various size-scales. Moisture diffuses into these voids. During reflow soldering, the simultaneous action of thermal stresses and moisture-induced internal pressure drives both pre-existing and newly nucleated voids to grow and coalesce, causing adhesive failure. In this work, a nonuniform initial porosity distribution in the adhesive is assumed. The entire adhesive is modeled by void-containing cells that incorporate vapor pressure effects on void growth and coalescence through an extended Gurson porous material model. Our computations show that increasing nonuniformity in the adhesive's initial porosity f 0 drives the formation of multiple damage zones. Under the influence of vapor pressure or residual stresses, interface delamination becomes the likely failure mode in low mean porosity adhesives with nonuniform f 0. For high mean porosity adhesives, the combination of vapor pressure and nonuniform f 0 distribution induces large-scale voiding throughout the adhesive. Residual stresses further accelerate voiding activity and growth of the damage zones, resulting in brittle-like adhesive rupture. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Thermal Cycle Reliability and Failure Mechanisms of CCGA and PBGA Assemblies With and Without Corner Staking

    Publication Year: 2008 , Page(s): 285 - 296
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2938 KB) |  | HTML iconHTML  

    Area array packages (AAPs) with 1.27 mm pitch have been the packages of choice for commercial applications; they are now starting to be implemented for use in military and aerospace applications. Thermal cycling characteristics of plastic ball grid array (PBGA) and chip scale package assemblies, because of their wide usage for commercial applications, have been extensively reported on in literature. Thermal cycling represents the on-off environmental condition for most electronic products and therefore is a key factor that defines reliability. However, very limited data is available for thermal cycling behavior of ceramic packages commonly used for the aerospace applications. For high reliability applications, numerous AAPs are available with an identical design pattern both in ceramic and plastic packages. This paper compares assembly reliability of ceramic and plastic packages with the identical inputs/outputs (I/Os) and pattern. The ceramic package was in the form of ceramic column grid array (CCGA) with 560 I/Os peripheral array with the identical pad design as its plastic counterpart. The effects of the following key parameters on reliability of both CCGA and PBGA assemblies were investigated:(1) thermal cycle ranges, -50degC/75degC, -55degC/100degC, and -55degC/125degC; (2) corner staking on failure mechanisms for two thermal cycle profiles, -55degC/125degC and -50degC/75degC; (3) package interchangeability, i.e., using PBGA package on CCGA pad design with a larger pad. Packages were assembled on polyimide boards and their daisy chains were continuously monitored. Optical photomicrographs were taken at various thermal cycle intervals to document damage progress and behavior. Representative samples along with their cross-sectional photomicrographs at higher magnification, taken by scanning electron microscopy and analyzed by energy dispersive X-ray, are- - also presented. The inspection documents were used to determine crack propagation and failure analyses for packages with and without corner staking. In assemblies with corner staking adhesive, a transition in failure from corner columns to center columns was observed when maximum temperature in thermal cycling profiles changed. This is a new failure mechanism not reported on in literature. Finite element analysis (FEA) was used to predict such global failure mode changes. FEA findings are also presented. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Interfacial Adhesion Study for SAM Induced Covalent Bonded Copper-EMC Interface by Molecular Dynamics Simulation

    Publication Year: 2008 , Page(s): 297 - 308
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1754 KB) |  | HTML iconHTML  

    Copper-epoxy molding compound (Cu-EMC) interface is known to be the weakest joint in the electronic packages, which causes delamination during a reliability test. A prime reason is the lack of adhesion between Cu and the epoxy compound. To solve the problem, a self-assembly monolayer (SAM) is introduced to improve adhesion of copper-epoxy system. Thiols/disulfides, which can effectively deposited on Cu surface, were selected as the SAM to act as surface modifier to Cu substrate. The selection of thiols/disulfides candidate with an appropriate tail group is essential for the adhesion enhancement. To promote adhesion, the SAM structures should be able to form high density covalent bonds with the EMC. This paper focuses on the use of molecular dynamics (MD) simulation to study the covalent bonds effect on the adhesion in Cu-SAM-EMC system. The data is used as a means to select SAM candidates with good interfacial adhesion strength. In this study, MD simulation models of the Cu-SAM-EMC system with covalent bonding and optimized SAM density were built to evaluate the interfacial bonding energy between the EMC and SAM coated substrate. The results show that the interfacial bonding energy changed with different SAM coatings on the Cu substrate. The modelling results were compared with the experimental button shear data. The shear test shows that when Cu substrates have been coated with SAM with amine/amide groups, adhesion increased significantly. A consistent qualitative trend is observed in the results calculated by the MD simulations. The sheared samples, which were analysed by the time-of-flight secondary ion mass spectrometer techniques, further confirmed the existence of covalent bonds at the interface. This proves that the covalent bonding at the interface is a key mechanism in enhancing the interfacial adhesion. This work illustrates that MD can help in understanding the behavior of bonding of SAM to polymer at the molecular scale. The MD can be a useful tool to se- - lect SAM structure for adhesion promotion in a Cu-SAM-EMC system. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • High Cycle Cyclic Torsion Fatigue of PBGA Pb-Free Solder Joints

    Publication Year: 2008 , Page(s): 309 - 314
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (743 KB) |  | HTML iconHTML  

    In this study, a comprehensive experimental and numerical approach was used to investigate high cycle cyclic torsion fatigue behavior of lead-free solder joints in a plastic ball grid array (PBGA) package. The test vehicle was a commercial laptop motherboard. The motherboard was subjected to torsional loading and life tests were conducted. Using finite element analysis (FEA), the test assembly was simulated as a global model and the BGA component was simulated as a local model. Strains measured on the motherboard surface near by the BGA were used to calibrate the FEA models. By combining the life test results and FEA simulations, a high cycle fatigue model for the lead-free solder joints was generated based on the Coffin-Manson strain-range fatigue damage model. This model can now be used to predict the cycles to failure of BGA interconnects for new electronic product design under cyclic torsion loading. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Realization of Ultra Fine Pitch Traces on LCP Substrates

    Publication Year: 2008 , Page(s): 315 - 321
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2179 KB) |  | HTML iconHTML  

    Liquid crystal polymer (LCP) is being utilized in a variety of applications that could benefit from the realization of ultra fine pitch conductive traces on the surface of the LCP substrate. LCP has unique chemical properties that not only benefit the intended application, but can also be exploited to realize ultra fine pitch traces. Through a series of experiments, it was discovered that a thin film of Ti can form TiC with the surface of an Ar ion ablated LCP substrate. This layer then provides sufficient adhesion for other metals to be deposited so that ultra fine pitch traces can be patterned. Using this process, 10 mum wide traces on a 20 mum pitch with high yield were demonstrated and analyzed. Smaller feature size test structures were also demonstrated. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Shape Optimization of Micro-Channel Heat Sink for Micro-Electronic Cooling

    Publication Year: 2008 , Page(s): 322 - 330
    Cited by:  Papers (13)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (725 KB) |  | HTML iconHTML  

    A numerical investigation of 3D fluid flow and heat transfer in a rectangular micro-channel has been carried out using water as a cooling fluid in a silicon substrate. Navier-Stokes and energy equations for laminar flow and conjugate heat transfer are solved using a finite volume solver. Solutions are first carefully validated with available analytical and experimental results; the shape of the micro-channel is then optimized using surrogate methods. Ratios of the width of the micro-channel to the depth and the width of the fin to the depth are selected as design variables. Design points are selected through a four-level full factorial design. A single objective function thermal resistance, formulated using pumping power as a constraint, is optimized. Mass flow rate is adjusted by the constant pumping power constraint. Response surface approximation, kriging, and radial basis neural network methods are applied to construct surrogates and the optimum point is searched by sequential quadratic programming. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Thermal Cycling Aging Effect on the Shear Strength, Microstructure, Intermetallic Compounds (IMC) and Crack Initiation and Propagation of Reflow Soldered Sn-3.8Ag-0.7Cu and Wave Soldered Sn-3.5Ag Ceramic Chip Components

    Publication Year: 2008 , Page(s): 331 - 344
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (3320 KB) |  | HTML iconHTML  

    Temperature cycling of electronic components was carried out at two different temperature profiles, the first ranging between -55degC and 100degC (TC1) and the second between 0degC and 100degC (TC2). Totally, 7000 cycles were run at TC1 and 14500cycles at TC2. The test board's top-side components were surface mounted using Sn-3.8Ag-0.7Cu solder alloy, and the bottom side surface mount devices (SMD) were wave soldered with Sn-3.5Ag alloy. The solder joint degradation was investigated as a function of cycle number by means of shear force measurements and cross-sectioning. The shear force drop was correlated to both crack initiation time and propagation rate, and microstructural changes. The effect of manufacturing process (reflow versus wave soldering) and component size (0805 versus 0603 components) on the shear force were also investigated. For both reflow and wave soldered components, the harsher the test environment the faster and largest the decrease in shear force. The shear force is higher for the 0805 components compared to the 0603. The effect of component size on the residual shear force is higher for the testing condition TC1. TC1 also seems to have a higher effect on the residual shear force compared to TC2. The main difference between wave soldered and reflow soldered components is that the shear force is in average higher for the wave soldered components compared to the reflow soldered. For the reflow soldered components using SAC, the microstructure coarsens as a function of temperature cycling, especially the Ag3Sn intermetallic particles. Furthermore, this alloy shows an increase in intermetallic compound (IMC) layer thickness (Cu-Ni-Sn), and its growth is controlled by a diffusion mechanism. The IMC growth coefficient is for the SAC system tested at TC1 0.0231 mum/h1/2 (0.00053 mum/h) and for TC2 0.0054 mum/h1/2 (2.9*10-5 mum/h). The microstructural changes during thermal cycling are a result of- - both static and strain-enhanced aging. For the wave soldered components the microstructure also became coarser, however, the IMC layer (Ni3Sn4) thickness did not change. The IMC layer growth does not affect the shear force for the test conditions applied in this work. The shear force decrease observed in the present work as a result of thermal cycling is a result of both microstructural coarsening and crack propagation inside the solder joint. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Moisture Lifetime Testing of RF MEMS Switches Packaged in Liquid Crystal Polymer

    Publication Year: 2008 , Page(s): 345 - 350
    Cited by:  Papers (3)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (899 KB) |  | HTML iconHTML  

    This paper presents for the first time the effects of moisture on radio frequency microelectromechanical systems (MEMS) switches packaged entirely inside a flexible, organic polymer [namely, liquid crystal polymer (LCP)]. Moisture tests were administered at 100degC and 100% relative humidity to evaluate long-term exposures and at 85degC and 85% relative humidity to evaluate short-term exposures. The effect of the moisture was quantified by before and after S-parameter measurements, by a weight gain analysis, and by visual inspection. Both global and localized bonding techniques were investigated to compare the best-case scenario to a more practical case. The effects of an 18 mum thick copper layer on both sides of the package were studied as well as the size of the bonding contact area. It was found that many packages that passed the Military Standard 883 G, Method 1014.12 for seal quality were unable to provide adequate protection from moisture. This indicates that the requirements for MEMS devices is more rigorous than the Military Standard. This standard is commonly quoted in literature as a metric for qualifying polymer packaging techniques. This paper demonstrates the necessity for proper testing of MEMS devices in a moist environment. It has been determined that for the bonding methods presented in this paper, an LCP packaged MEMS switch could potentially survive 7-10 h in jungle conditions, 5-7 weeks in ambient conditions, or 1.4-1.8 years in desert conditions. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Geometrical Design of Plate-Fin Heat Sinks Using Hybridization of MOEA and RSM

    Publication Year: 2008 , Page(s): 351 - 360
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1213 KB) |  | HTML iconHTML  

    The work in this paper is aimed at demonstrating the practical multiobjective optimization of plate-fin heat sinks and the superiority of using a combined response surface method and multiobjective evolutionary optimizer over solely using the evolutionary optimizer. The design problem assigned is to minimize a heat sink junction temperature and fan pumping power. Design variables determine a heat sink geometry and inlet air velocity. Design constraints are given in such a way that the maximum and minimum fin heights are properly limited. Function evaluation is carried out by using finite volume analysis software. Two multiobjective evolutionary optimization strategies, real-code strength Pareto evolutionary algorithm with and without the use of a response surface technique, are implemented to explore the Pareto optimal front. The optimum results obtained from both design approaches are compared and discussed. It is illustrated that the multiobjective evolutionary technique is a powerful tool for the multiobjective design of electronic air-cooled heat sinks. With the same design conditions and an equal number of function evaluations, the multiobjective optimizer in association with the response surface technique totally outperforms the other. The design parameters affecting the diversity of the Pareto front include fin thickness, fin height distribution, and inlet air velocity while the plate base thickness and the total number of fins of the non-dominated solutions tend to approach certain values. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Investigation of Mechanical and Electrical Characteristics for Cracked Conductive Particle in Anisotropic Conductive Adhesive (ACA) Assembly

    Publication Year: 2008 , Page(s): 361 - 369
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1398 KB) |  | HTML iconHTML  

    In an anisotropic conductive adhesive (ACA) assembly, the electrical conduction is usually achieved with the conductive particles between the bumps of integrated circuit (IC) and corresponding conductive tracks on the glass substrate. Fully understanding of the mechanical and electrical characteristics of ACA particles can help to optimize the assembly process and improve the reliability of ACA interconnection. Most conductive particles used in the ACA assembly are with cracks in the metal coating of the particles after the ACA bonding. This paper introduced the fracture analysis by applying the cohesive elements in the numerical model of the nickel-coated polymer particle and further simulating the cracks initiation and propagation in the nickel coating during the ACA bonding. The simulation results showed that the stress distribution on the nickel-coated particle with cracks was significantly different from that on the nickel-coated particle without crack, indicating that the stress analysis by taking the crack into consideration is very important for the reliability assessment of the ACA interconnection. The stress analysis of cohesive elements indicated that the cracks initiated at the central area of the nickel coating and propagated to the polar area. Furthermore, by the introduction of a new parameter of the virtual resistance, a mathematical model was established to describe the electrical characteristics of the nickel-coated particle with cracks. The particle resistance of the nickel-coated particle with cracks was found to be much higher than that of the particle without crack in the optimized bonding pressure range, indicating that it is necessary to take the crack into consideration for the particle conduction analysis as well. Therefore, the fracture analysis on the conductive particle by taking the crack into consideration could accurately evaluate the reliability of ACA interconnection and avoid serious reliability issues. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Influence of Sn Grain Size and Orientation on the Thermomechanical Response and Reliability of Pb-free Solder Joints

    Publication Year: 2008 , Page(s): 370 - 381
    Cited by:  Papers (24)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2384 KB) |  | HTML iconHTML  

    The size and crystal orientation of Sn grains in Pb-free, near eutectic Sn-Ag-Cu solder joints were examined. A clear dependence of the thermomechanical fatigue response of these solder joints on Sn grain orientation was observed (Sn has a body centered tetragonal crystal structure). Fabricated joints tend to have three orientations in a cyclic twin relationship, but among the population of solder balls, this orientation triplet appears to be randomly oriented. In thermally cycled joints, solder balls with dominant Sn grains having the particular orientation with the c-axis nearly parallel to the plane of the substrate were observed to fail before neighboring balls with different orientations. This results from the fact that the coefficient of thermal expansion of Sn in the basal plane (along the alpha-axis) is half the value along the c-axis; joints observed to be damaged had the maximum coefficient of thermal expansion mismatch between solder and substrate at the joint interface, as well as a tensile stress modes during the hot part of the thermal cycle. Localized recrystallization was observed in regions of maximum strain caused by differential expansion conditions, and its connection with crack nucleation is discussed. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Evaluation of Thermal Resistance Matrix Method for an Embedded Power Electronic Module

    Publication Year: 2008 , Page(s): 382 - 387
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (676 KB) |  | HTML iconHTML  

    Thermal characterization provides data on the thermal performance of electronic components under given cooling conditions. The most common thermal characterization parameter used to characterize the behavior of electronic components is the thermal resistance. In this work, experiments are conducted to obtain thermal characterization data for different chips in a multichip package. Using this data, it is shown that the assumption of a linear temperature rise with input power is valid within the expected range of operation of the electronic module. Secondly, the applicability of a resistance matrix superposition methodology to the packaging structure of an integrated power electronic module is evaluated. The temperatures and the associated uncertainties involved in using the resistance matrix superposition method are compared to those obtained directly by powering all chips. It is shown that for any arbitrary power losses from the chips, the resistance matrix superposition method can predict the temperatures of a multichip package with reasonable accuracy for temperature rise up to 50degC. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • On the Homogenization of Multilayered Interconnect for Interfacial Fracture Analysis

    Publication Year: 2008 , Page(s): 388 - 398
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (839 KB) |  | HTML iconHTML  

    The interface crack problem for Cu/low-k interconnect is considered using global-and-local finite element analysis. In the global analysis the thin film interconnect is represented by a homogenized layer with equivalent material properties. Local model around the interface crack tip is analyzed with displacement boundary condition extracted from the global modeling result to determine the fracture mechanics parameters. It is shown that, for the global-and-local modeling approach, interconnect homogenization using representative volume element (RVE) approach provides accurate prediction on the fracture mechanics parameters for an interface crack under either thermal or mechanical loads, while significant error occurs when the interconnect, even though having thickness less than 1/100 of the whole component thickness, is neglected in the global analysis. The problem of an interface crack between low-k dielectric and etch-stop thin film in a flip-chip package under thermal excursion is also investigated as an application example of the global-and-local modeling approach. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Driver IC and COG Package Design

    Publication Year: 2008 , Page(s): 399 - 406
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2128 KB) |  | HTML iconHTML  

    This paper investigates the interconnection between the driver integrated circuit (IC) and glass substrate via anisotropic conductive adhesive (ACF) of chip on glass package. The conductive particle deformation is evaluated using a novel method, optical microscope (OM) inspection. The proposed method is more convenient than the traditional approach using scanning electron microscopy applied in the manufacturing process. Interconnection performance is easily judged using OM, allowing poor interconnection between the driver IC and glass substrate to be screened out. Several types of driver ICs with different bump area ratios (total input bump area/total output bump area, input/output ratio) and length/width (L/W) ratios are designed in this experiment. The conductive particle deformations are investigated in this study. Driver ICs with L/W ratios larger than 15 have better conductive particle deformation uniformity at each position. The average deformation degree at the driver IC center position is larger than that at the side and edge positions. The deformation degree at the input position with a smaller bump area is better than that at the output position. The conductive resistance increases with the reliability testing time because of the thermal stress effect and softening of the ACF polymer material. The deformation degree is related to the conductive resistance of the interconnection. The conductive resistance is lower at the center and input positions with larger deformation degree. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Effect of Local Hot Spots on the Maximum Dissipation Rates During Flow Boiling in a Microchannel

    Publication Year: 2008 , Page(s): 407 - 416
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1622 KB) |  | HTML iconHTML  

    One of the most promising technologies to replace air-cooling of micro-processor chips is flow boiling in microchannels. The very high heat flux dissipation from micro-processor chips is highly non-uniform due to the presence of multiple localized hot spots usually related to the localization of bridges and gate oxide shorts. Previous studies focused on the performance of microchannels under uniform heating conditions. Recently, Revellin and Thome (see Int. J. Heat Mass Transf., vol 51, no.5-6, p. 1216-25, 2008) have proposed a new theoretical model to predict the critical heat flux (CHF) in microchannels. This model has been modified here to take into account a non-uniform axial heat flux along a microchannel. The model is used here to perform a local hot spot study to investigate the effects of fluid, saturation temperature, mass flux, microchannel diameter, heated length, size, location and number of hot spots as well as the distance between two consecutive hot spots. Based on the present simulations, to best dissipate a hot spot's heat flux, microchannel heat sinks should follow the following recommendations for a channel of fixed length: determine the optimum channel diameter for the fluid (typically either very small or large is best), utilize as high of mass flux as feasible, and design with as low of saturation temperature as possible. Furthermore, the local hot spot size should be as small as possible, the number of local hot spots as few as possible and the distance between two hot spots as large as possible. Utilizing the present numerical method for individual microchannels arranged in parallel in a multi-microchannel cooling element, it is possible to simulate the entire power dissipation profile of a microprocessor die for local limits of CHF. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Estimating the Engineering Properties of Electronic Packaging Materials

    Publication Year: 2008 , Page(s): 417 - 424
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (539 KB) |  | HTML iconHTML  

    Silica-filled epoxy composites represent an important class of electronic packaging materials. In this paper, a series of semi-empirical equations are proposed for estimating the density, temperature-dependant modulus, expansion coefficient and Poisson's ratio of silica-filled epoxy composites as a function of the silica content and glass transition temperature. The density and expansion coefficients are calculated using the rule of mixtures, while the composite moduli in the glassy and rubbery plateaus are derived using the Halpin-Tsai equation, the theory of rubber visco-elasticity, and elementary considerations of the polymer cross-link density. A four-parameter sigmoidal function is shown to account well for the composite stiffness in the transition region between the glassy and rubbery states, while a three-parameter single rise to maximum equation expresses the change in the composite's Poisson ratio with silica content. The models are corroborated against a large data library of actual packaging materials. Their usefulness in calculating e.g., the warpage in a plastic ball-grid array package is demonstrated in a worked example. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Micro-Arcing and Arc Erosion Minimization Using a DC Hybrid Switching Device

    Publication Year: 2008 , Page(s): 425 - 430
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (848 KB) |  | HTML iconHTML  

    Hybrid switching devices utilize the advantages of both conventional electrical contacts and solid state electronics to minimize arcing during opening and closing operations. This can result in higher reliability and reduces the need for high cost specialist contact materials. The hybrid switch does not eliminate arcing completely, due to the inductive nature of circuits; micro-arcing is known to occur. An experimental dc hybrid switching device is introduced which minimizes arcing for 42 V applications. The characteristics of micro-arcing are investigated to determine the factors which influence the duration of micro-arcs. Surface profiling techniques are used to determine low level contact erosion. The magnitude of contact erosion is related to the micro-arcing. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.

Aims & Scope

IEEE Transactions on Components and Packaging Technologies publishes research and applications articles on the modeling, building blocks, technical infrastructure, and analysis underpinning electronic, photonic, MEMS and sensor packaging.

 

This Transaction ceased production in 2010. The current publication is titled IEEE Transactions on Components, Packaging, and Manufacturing Technology.

Full Aims & Scope

Meet Our Editors

Editor-in-Chief
Koneru Ramakrishna
Freescale Semiconductor, Inc.