Problems In Electronic Packaging Research Articles

An Automatic Finite Element Method-Boundary Element Method Coupling Method for Elastic–Plastic Problems of Multiscale Structures in Electronic Packaging

Abstract We introduce a coupled finite and boundary element method for elastic-plastic analysis over multiscale electronic packaging structures. Based on the finite element-boundary element (FE-BE) coupling algorithm, an automatic implementation procedure for the coupling of the abaqus with a self-written elastic BE code is introduced for elastic problems. In the mixed finite element method (FEM)-boundary element method (BEM) model, the effective stiffness and effective forces at the interfacial boundary are evaluated by the self-written BE code. Then, the obtained effective stiffness and effective forces are assembled to the global FE formulations by using the user subroutine (UEL) in abaqus. Numerical simulation of structures with plastic deformation, stress concentration, etc. is carried out by using FEM theory. The boundary element method is used for linear elastic domains with large-scale structures. The proposed method offers several key improvements compared with current analysis methods available for multiscale electronic packaging structures. The benefits are: (i) the powerful pre- and postprocessing of abaqus; (ii) the higher accuracy of the solution; (iii) the computational cost and time can be reduced by using the scheme; and (iv) solving systems with infinite extension by using the BEM as a supplement. Furthermore, we demonstrate the ability of the proposed approach to handle multiscale structures in electronic packaging problems.

An isogeometric boundary element method for heat transfer problems of multiscale structures in electronic packaging with arbitrary heat sources

We present an isogeometric boundary element method (IGABEM) capable of studying heat transfer problems for multiscale structures in electronic packaging problems. This method offers a number of key improvements compared with current analysis methods available for electronic packaging problems. The method benefits from the accuracy, computational efficiency and CAD integration that have consistently been shown as features of the IGABEM. In addition, the current method can efficiently evaluate the nearly singular integrals caused by multiscale structures, owing to the use of a proposed hybrid integration scheme. By changing a tolerance, the scheme enables engineers to achieve any desired balance between accuracy and computational efficiency as may be appropriate to the situation. To study heat transfer problems with an arbitrary heat source, the radial integral method is used to transform the domain integral to an equivalent boundary integral. Numerical results are compared with available analytical solutions and finite element solutions and demonstrate the effectiveness of the proposed approach.

Thermal analysis of electronic packaging structure using isogeometric boundary element method

The purpose of this paper is to carry out heat transfer analysis of integrated circuit (IC) packaging structures by the isogemoetric boundary element method (IGABEM). In service time, chips of electronic packaging structure produce lots of heat, which leads to resultant equations including domain integrals. In this work, the radial integration method is used to deal with domain integrals caused by the heat source. Since material properties of electronic packaging structure are piecewise continuous, the subregion isogemoetric boundary element method is introduced in the present IGABEM. In addition, the multi-scale property of structure leads to challenge of IGABEM analysis in electronic packaging problems. This largely results from the difficulty of integrating nearly singular integrals in an accurate and efficient manner. To deal with this problem, a hybrid nearly singular integration scheme, which delivers results of engineering accuracy in an optimal time is used in this work. Finally, a set of numerical examples demonstrate the ability of the present IGABEM to produce accurate temperature distributions.

Reduction of Epistemic Model Uncertainty in Simulation-Based Multidisciplinary Design

Model uncertainty is a significant source of epistemic uncertainty that affects the prediction of a multidisciplinary system. In order to achieve a reliable design, it is critical to ensure that the disciplinary/subsystem simulation models are trustworthy, so that the aggregated uncertainty of system quantities of interest (QOIs) is acceptable. Reduction of model uncertainty can be achieved by gathering additional experiments and simulations data; however, resource allocation for multidisciplinary design optimization (MDO) and analysis remains a challenging task due to the complex structure of the system, which involves decision makings about where (sampling locations), what (disciplinary responses), and which type (simulations versus experiments) for allocating more resources. Instead of trying to concurrently make the above decisions, which would be generally intractable, we develop a novel approach in this paper to break the decision making into a sequential procedure. First, a multidisciplinary uncertainty analysis (MUA) is developed to identify the input settings with unacceptable amounts of uncertainty with respect to the system QOIs. Next, a multidisciplinary statistical sensitivity analysis (MSSA) is developed to investigate the relative contributions of (functional) disciplinary responses to the uncertainty of system QOIs. The input settings and critical responses to allocate resources are selected based on the results from MUA and MSSA, with the aid of a new correlation analysis derived from spatial-random-process (SRP) modeling concepts, ensuring the sparsity of the selected inputs. Finally, an enhanced preposterior analysis predicts the effectiveness of allocating experimental and/or computational resource to answer the question about which type of resource to allocate. The proposed method is applied to a benchmark electronic packaging problem to demonstrate how epistemic model uncertainty is gradually reduced via resource allocation for data gathering.

Multidisciplinary Inverse Reliability Analysis Based on Collaborative Optimization with Combination of Linear Approximations

Multidisciplinary reliability is an important part of the reliability-based multidisciplinary design optimization (RBMDO). However, it usually has a considerable amount of calculation. The purpose of this paper is to improve the computational efficiency of multidisciplinary inverse reliability analysis. A multidisciplinary inverse reliability analysis method based on collaborative optimization with combination of linear approximations (CLA-CO) is proposed in this paper. In the proposed method, the multidisciplinary reliability assessment problem is first transformed into a problem of most probable failure point (MPP) search of inverse reliability, and then the process of searching for MPP of multidisciplinary inverse reliability is performed based on the framework of CLA-CO. This method improves the MPP searching process through two elements. One is treating the discipline analyses as the equality constraints in the subsystem optimization, and the other is using linear approximations corresponding to subsystem responses as the replacement of the consistency equality constraint in system optimization. With these two elements, the proposed method realizes the parallel analysis of each discipline, and it also has a higher computational efficiency. Additionally, there are no difficulties in applying the proposed method to problems with nonnormal distribution variables. One mathematical test problem and an electronic packaging problem are used to demonstrate the effectiveness of the proposed method.

A New Direction in Computational Electromagnetics: Solving Large Problems Using the Parallel FDTD on the BlueGene/L Supercomputer Providing Teraflop-Level Performance

Rapid developments in high-performance supercomputers, with upward of 65,536 processors and 32 terabytes of memory, have dramatically changed the landscape in computational electromagnetics. The IBM BlueGene/L supercomputer are examples. They have recently made it possible to solve extremely large problems efficiently. For instance, they have reduced 52 days of simulation on a single Pentium 4 processor to only about 10 minutes on 4000 processors in a BlueGene/L supercomputer. In this article, we investigate the performance of a parallel Finite-Difference Time-Domain (FDTD) code on a large BlueGene/L system. We show that the efficiency of the code is excellent, and can reach up to 90%. The code has been used to simulate a number of electrically large problems, including a 100 * 100 patch antenna array, a 144-element dual- polarized Vivaldi array, a 40-element helical antenna array, and an electronic packaging problem. The results presented serve to demonstrate the efficiency of the parallelization of the code on the BlueGene/L system. In addition, we also introduce the development of the high-performance Beowulf clusters for simulation of electrically large problems.

Parametric and Optimal Design in Electronic Packaging Using DSC: Computational, Geometrical, and Material Aspects

Abstract The disturbed state concept (DSC) with the hierarchical single surface (HISS) plasticity model have been proposed and validated previously for a wide range of problems in electronic packaging. In this paper, detailed analyses are performed with the DSC∕HISS model to study the effect of various factors, such as computational and geometrical aspects and material parameters, on the failure life of chip substrate systems. The results and the methodology can be used for parametric analyses and optimal design of problems in electronic packaging.

Efficient Uncertainty Analysis Methods for Multidisciplinary Robust Design

Efficient Uncertainty Analysis Methods for Multidisciplinary Robust Design

Optimal simultaneous interpolation/extrapolation algorithm of electromagnetic responses in time and frequency domains

In this paper, an optimal simultaneous interpolation and extrapolation algorithm in the time and frequency domains is carried out by adaptively choosing the order of the associate Hermite (AH) expansion. Due to the isomorphism of the AH function and its Fourier transform, the time-domain signal and its corresponding frequency-domain transform can be expanded as two isomorphic AH expansions, that can be used for simultaneous interpolation and extrapolation in the time and frequency domains from the partial sampled data of the two waveforms. By using an optimization algorithm, the origin of the expansion and the optimal scaling factor can be found. Hence, by using an adaptive procedure, the order of the expansion can be chosen that leads to accurate interpolation and extrapolation. Some numerical examples are presented to illustrate the efficiency of this method for the complex signal both with and without random noise. The proposed algorithm is also applied to analyze the time- and frequency-domain responses of the ground bounce and lead frame problems in electronic packaging in which the proposed algorithm remains stable when a large order of Hermite expansion is required.

Plastic encapsulated components for cars

Thermal management in electronics packaging is important. Thermal stress greatly affects reliability and aging of electronic circuits. Our group developed a thermal simulation tool named TRESCOM for investigating thermal problems in electronic packaging. We used this tool for steady-state and dynamic analyses of the thermal qualities of PLCC and CLCC components. Our investigation demonstrated the surprising result that the thermal performance of the plastic encapsulated components is superior to hermetically sealed ceramic components. We conclude that plastic packages are reliable and can compete with ceramic packages at the elevated temperatures that are found in automotive applications.

Applications of FEM for multiple laminated structure in electronic packaging

A special finite-element method for multiple laminated structure, previously proposed by the authors, is presented here. It can provide attractive results without three-dimensional finite-element discretization and can be applied to electronic packaging problems. The thermal stress analysis of the basic IC model, the practical IC model with lead fingers and the electronic printed board with solder bump joints are selected as the problems to deal with, and analyzed in detail. From the results of the basic IC model, the influences of varying chip size and package thickness for the stress distributions, are presented. The causes of failure for the real IC device are presented from the results of the practical IC model. In addition, influences of the solder joint arrangements for the thermal stresses are presented from the results of the electronic printed board with solder bump joints.

Phase-shifting analysis in moire´ interferometry and its applications in electronic packaging

In layered materials and structures, it is essential to observe stress and strain concentrations, strain gradients, failure initiation and growth, and local microstructure evolution. In this study, an innovative phase-shifting technique is proposed, coupled with image-processing software, to investigate several interesting problems in electronic packaging. A window-based graphics interface for phase shifting in a moire interferometry system is introduced. The phase shifting is accomplished by driving the reference grating in the moire interferometry system with a low-voltage piezo stack. Three images obtained from three shifts and the original image are used to derive the phase diagram, which is used for displacement and strain calculations. Automatic fringe numbering is achieved by the phase shifting, which significantly simplifies the traditional fringe-counting and -ranking process. The strain calculation is also automatic, utilizing the space derivative of the displacement. A three- point bending beam is used for the demonstration. In addition, a power plastic IC package and a flip-chip package are selected to demonstrate the power of the system. A nanoscale deformation field is obtained for both the corner area and the flip-chip solder balls.

Thermomechanical Finite Element Analysis of Problems in Electronic Packaging Using the Disturbed State Concept: Part 1—Theory and Formulation

Accurate prediction of the thermomechanical cyclic behavior of joints and interfaces in semiconductor devices is essential for their reliable design. In order to understand and predict the behavior of such interfaces there is a need for improved and unified constitutive models that can include elastic, inelastic, viscous, and temperature dependent microstructural behavior. Furthermore, such unified material models should be implemented in finite element procedures so as to yield accurate and reliable predictions of stresses, strains, deformations, microcracking, damage, and number of cycles to failure due to thermomechanical loading. The main objective of this paper is to present implementation of such an unified constitutive model in a finite element procedure and its application to typical problems in electronic packaging; details of the constitutive model are given by Desai et al. (1995). Details of the theoretical formulation is presented in this Part 1, while its applications and validations are presented in Part 2, Basaran et al. (1998).

Thermomechanical Finite Element Analysis of Problems in Electronic Packaging Using the Disturbed State Concept: Part 2—Verification and Application

The finite element procedure with the unified disturbed state modeling concept presented in Part I, Basaran et al. (1998), is verified here with respect to laboratory test results for Pb40/Sn60 eutectic solder alloy. This solder alloy is a commonly used interconnection material for surface mount technology packages. It is demonstrated that the proposed procedure provides highly satisfactory correlation with the observed laboratory behavior of materials and with test results for a chip-substrate system simulated in the laboratory.

Thermomechanical analysis in electronic packaging with unified constitutive model for materials and joints

A unified constitutive modeling approach based on the disturbed state concept (DSC) provides improved characterization of thermomechanical response of joining (solders), ceramics and printed wire board (PWB) materials in electronic packaging. Various versions in the DSC approach are calibrated and validated with respect to laboratory test data, and are implemented in a nonlinear finite element (FE) procedure. The hierarchical nature of this procedure permits the user to choose a constitutive model, simple (elastic) to sophisticated (elastovisco-plastic with disturbance), depending upon the material and need. The FE is used to analyze thermomechanical behavior of two typical problems: (1) leadless ceramic chip carrier (LCCC) package; (2) solder ball connect (SBC) package. The FE results under cyclic thermal loading are compared with experimental data for the two packages, and with a previous FE analysis for the SBC package. In conjunction with the idea of critical disturbance at which thermal fatigue failure can occur, the analyzes allow identification of cycles to failure, N/sub f/, and evaluation of reliability of the package. In the case of the SBC package, the analysis permits an evaluation of ball spacing on the thermomechanical behavior. The DSC approach can provide an integrated and improved procedure compared to available models for elastic, plastic, creep strains, and microcracking leading to degradation of strength and fatigue failure for a wide range of problems in electronic packaging under thermomechanical loading.

Thermomechanical Response of Materials and Interfaces in Electronic Packaging: Part II—Unified Constitutive Models, Validation, and Design

The constitutive modeling approach based on the disturbed state concept (DSC) described in Part I, provides a unified basis for the characterization of thermomechanical response of materials and joints in electronic chip-substrate systems. Using the material constants given in Part I, the DSC model predictions, obtained by integrating the incremental constitutive equations, are shown here to provide satisfactory backpredietions of stress-strain, fatigue, and failure responses of typical solder materials. The DSC also provides a simple criterion based on the critical disturbance to identify cyclic fatigue failure. Model predictions show good correlation with those from previous models. It is also shown how the DSC model can be used for design applications. Overall, based on Papers I and II, it can be stated that the DSC can provide a new and powerful means to characterize the thermomechanical behavior of materials and joints in a number of problems in electronic packaging.

Thermomechanical Response of Materials and Interfaces in Electronic Packaging: Part I—Unified Constitutive Model and Calibration

The disturbed state concept (DSC) presented here provides a unified and versatile methodology for constitutive modeling of thermomechanical response of materials and interfaces/joints in electronic chip-substrate systems. It allows for inclusion of such important features as elastic, plastic and creep strains, microcracking and degradation, strengthening, and fatigue failure. It provides the flexibility to adopt different hierarchical versions in the range of simple (e.g., elastic) to sophisticated (thermoviscoplastic with microcracking and damage), depending on the user’s specific need. This paper presents the basic theory and procedures for finding parameters in the model based on laboratory test data and their values for typical solder materials. Validation of the models with respect to laboratory test behavior and different criteria for the identification of cyclic fatigue and failure, including a new criterion based on the DSC and design applications, are presented in the compendium paper (Part II, Desai et al., 1997). Based on these results, the DSC shows excellent potential for unified characterization of the stress-strain-strength and failure behavior of engineering materials in electronic packaging problems.

Fusion-related technology transfer at the Sandia National Laboratories

The technology Transfer Program at Sandia National Laboratories is focused on market pull and rapid commercialization. The emphasis is to apply lab strengths to problems of national importance by partnering with industry and universities with the result of enhancing the US economic competitiveness. The technology transfer of fusion-related technologies enhances the mission of the fusion program at Sandia. The short-term strategy in the Pulsed Power Center at Sandia is to develop teaming arrangements with other Sandia organizations to become participants in existing CRADAs. To that end, they are using the expertise and facilities in fusion-related lasers to participate in CRADAs for laser debridement with Massachusetts General Hospital and laser Light Detection and Ranging (LIDAR) with Mission Research Corporation. In addition, they are working with an existing CRADA partner to use the Quick Silver Code to solve advanced electronic packaging problems. The longer-term strategy is to establish CRADAs in surface treatment of metals with ion beams, deep penetration electron beam welding and food irradiation for disinfestation and sterilization. The strong interest shown by industry in these three areas demonstrates the potential commercial value in high average power electron and ion beam systems.

Aluminum composite materials for multichip modules

In the intensive materials development activities for electronic packaging and thermal management applications, the subclass of materials in which SiC particles reinforce aluminum alloy matrices has emerged as one with an especially attractive combination of physical properties, manufacturing flexibility, and cost. One benefit of these materials is the ability to tailor the physical properties through the selection of both reinforcement and alloy variables to match the thermal expansion coefficient of other electronic materials. In addition, the manufacturing flexibility of the various processes allows for shape complexity as well as selective reinforcement placement in the component to optimize system producibility. Finally, because raw materials are inherently inexpensive and low-cost production routes have been identified, aluminum composites may offer a range of cost-effective solutions to emerging problems in electronic packaging and thermal-management applications.