scholarly journals Theoretical and Experimental Investigation of Warpage Evolution of Flip Chip Package on Packaging during Fabrication

Materials ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 4816
Author(s):  
Hsien-Chie Cheng ◽  
Ling-Ching Tai ◽  
Yan-Cheng Liu
Keyword(s):  
Elastic Properties ◽  
Process Simulation ◽  
Flip Chip ◽  
Measurement Data ◽  
Viscoelastic Behavior ◽  
Mapping Method ◽  
Simulation Framework ◽  
Element Analysis ◽  
Analytical Estimate ◽  
Molding Compound

This study attempts to investigate the warpage behavior of a flip chip package-on-package (FCPoP) assembly during fabrication process. A process simulation framework that integrates thermal and mechanical finite element analysis (FEA), effective modeling and ANSYS element death-birth technique is introduced for effectively predicting the process-induced warpage. The mechanical FEA takes into account the viscoelastic behavior and cure shrinkage of the epoxy molding compound. In order to enhance the computational and modeling efficiency and retain the prediction accuracy at the same time, this study proposes a novel effective approach that combines the trace mapping method, rule of mixture and FEA to estimate the effective orthotropic elastic properties of the coreless substrate and core interposer. The study begins with experimental measurement of the temperature-dependent elastic and viscoelastic properties of the components in the assembly, followed by the prediction of the effective elastic properties of the orthotropic interposer and substrate. The predicted effective results are compared against the results of the ROM/analytical estimate and the FEA-based effective approach. Moreover, the warpages obtained from the proposed process simulation framework are validated by the in-line measurement data, and good agreement is presented. Finally, key factors that may influence process-induced warpage are examined via parametric analysis.

Characterization of Cure-Dependent Viscoelastic Behavior for Molding Compound and Application to Package Warpage Simulation

2009 ◽  
Author(s):  
Tz-Cheng Chiu ◽  
Je-Li Kung ◽  
Yi-Shao Lai
Keyword(s):  
Finite Element ◽  
Viscoelastic Model ◽  
Viscoelastic Behavior ◽  
Relaxation Modulus ◽  
Cure Kinetics ◽  
Constitutive Relationship ◽  
Element Analysis ◽  
Molding Compound ◽  
Modeling Methodology ◽  
Bga Package

In this study a process-dependent viscoelastic model is developed for considering the constitutive relationship of an epoxy molding compound. The process dependence is realized by incorporating the phenomenological models for the cure kinetics, the cure-dependent volume shrinkage, and the cure-dependent viscoelastic stress relaxation modulus into the constitutive model for the molding compound. The cure-dependent viscoelastic model is incorporated into numerical finite element analysis to simulate warpage of an overmolded chip scale ball grid array (BGA) package under uniform cooling from reflow to room temperature. The simulation results are compared to Shadow Moire´ experimental data for validating the modeling methodology. Additional finite element analyses are performed to investigate the influence of molding compound constitutive behavior (temperature-dependent elastic or viscoelastic) on the package warpage prediction, and to consider the package warpage evolution during the post-mold curing (PMC) process.

Numerical and Experimental Study of Interface Delamination in Flip Chip BGA Package

2010 ◽  
Vol 132 (1) ◽  
Author(s):  
Hu Guojun ◽  
Andrew A. O. Tay ◽  
Luan Jing-En ◽  
Ma Yiyi
Keyword(s):  
Thermal Expansion ◽  
Material Properties ◽  
Flip Chip ◽  
Coefficient Of Thermal Expansion ◽  
Element Analysis ◽  
Epoxy Molding Compound ◽  
Molding Compound ◽  
Interface Delamination ◽  
Underfill Material ◽  
Die Thickness

The reliability of the flip chip package is strongly influenced by underfill, which has a much higher coefficient of thermal expansion (CTE) compared with other packaging materials and leads to large thermomechanical stresses developed during the assembly processes. Thermal expansion mismatch between different materials causes interface delamination between epoxy molding compound and silicon die as well as interface delamination between underfill and silicon die. The main objective of this study is to investigate the effects of underfill material properties, fillet height, and silicon die thickness on the interface delamination between epoxy molding compound and silicon die during a lead-free solder reflow process based on the modified virtual crack closure method. Based on finite element analysis and experiment study, it can be concluded that the energy release rates at reflow temperature are the suitable criteria for the estimation of interface delamination. Furthermore, it is found that underfill material properties (elastic modulus, CTE, and chemical cure shrinkage), fillet height, and silicon die thickness can be optimized to reduce the risk of interface delamination between epoxy molding compound and silicon die in the flip chip ball grid array package.

Nonlinear Viscoelastic Finite Element Analysis of Adhesive Joints

1988 ◽  
Vol 16 (3) ◽  
pp. 146-170 ◽  
Author(s):  
S. Roy ◽  
J. N. Reddy
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Viscoelastic Behavior ◽  
Bonded Joints ◽  
Adhesively Bonded ◽  
Element Analysis ◽  
Adhesively Bonded Joints ◽  
Nonlinear Viscoelastic ◽  
Structural Failures ◽  
Updated Lagrangian

Abstract A good understanding of the process of adhesion from the mechanics viewpoint and the predictive capability for structural failures associated with adhesively bonded joints require a realistic modeling (both constitutive and kinematic) of the constituent materials. The present investigation deals with the development of an Updated Lagrangian formulation and the associated finite element analysis of adhesively bonded joints. The formulation accounts for the geometric nonlinearity of the adherends and the nonlinear viscoelastic behavior of the adhesive. Sample numerical problems are presented to show the stress and strain distributions in bonded joints.

Effect of agglomeration and dispersion on the elastic properties of polymer nanocomposites: A Monte Carlo finite element analysis

2016 ◽  
Vol 58 (3) ◽  
pp. 269-279 ◽  
Author(s):  
Hassan S. Hedia ◽  
Saad M. Aldousari ◽  
Ahmed K. Abdellatif ◽  
Gamal S. Abdelhaffez
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Monte Carlo ◽  
Polymer Nanocomposites ◽  
Elastic Properties ◽  
Element Analysis

Measurement and Calculation of Elastic Properties in Low Carbon Steel Sheet

2005 ◽  
Vol 495-497 ◽  
pp. 1591-1596 ◽  
Author(s):  
Vladimir Luzin ◽  
S. Banovic ◽  
Thomas Gnäupel-Herold ◽  
Henry Prask ◽  
R.E. Ricker
Keyword(s):  
Carbon Steel ◽  
Elastic Property ◽  
Elastic Properties ◽  
Steel Sheet ◽  
Low Carbon Steel ◽  
Low Carbon ◽  
Forming Process ◽  
Element Analysis ◽  
Wide Range ◽  
Carbon Steel Sheet

Low carbon steel (usually in sheet form) has found a wide range of applications in industry due to its high formability. The inner and outer panels of a car body are good examples of such an implementation. While low carbon steel has been used in this application for many decades, a reliable predictive capability of the forming process and “springback” has still not been achieved. NIST has been involved in addressing this and other formability problems for several years. In this paper, texture produced by the in-plane straining and its relationship to springback is reported. Low carbon steel sheet was examined in the as-received condition and after balanced biaxial straining to 25%. This was performed using the Marciniak in-plane stretching test. Both experimental measurements and numerical calculations have been utilized to evaluate anisotropy and evolution of the elastic properties during forming. We employ several techniques for elastic property measurements (dynamic mechanical analysis, static four point bending, mechanical resonance frequency measurements), and several calculation schemes (orientation distribution function averaging, finite element analysis) which are based on texture measurements (neutron diffraction, electron back scattering diffraction). The following objectives are pursued: a) To test a range of different experimental techniques for elastic property measurements in sheet metals; b) To validate numerical calculation methods of the elastic properties by experiments; c) To evaluate elastic property changes (and texture development) during biaxial straining. On the basis of the investigation, recommendations are made for the evaluation of elastic properties in textured sheet metal.

Analysis of Nonlinear Flexural Behavior of Thick Composites With Fiber Waviness

1999 ◽  
Author(s):  
H.-J. Chun ◽  
S. W. Lee ◽  
I. M. Daniel
Keyword(s):  
Finite Element ◽  
Composite Plate ◽  
Current Model ◽  
Geometrical Nonlinearity ◽  
Mapping Method ◽  
Flexural Behavior ◽  
Analysis Model ◽  
Element Analysis ◽  
Fiber Waviness ◽  
Thick Composites

Abstract A finite element analysis model was developed to predict flexural behavior of thick composites with uniform, graded and localized fiber waviness. In the analyses, material and geometrical nonlinearties due to fiber waviness were incorporated into the model utilizing energy density and an incremental method. In the model, two kinds of geometrical nonlinearity were considered, one due to reorientation of fibers and the other due to difference of curvatures from one finite element to another during deformation. The finite element analyses utilize the iterative mapping method to incorporate these geometrical nonlinear factors. The model was used to predict not only the flexural behavior of a flat thick composite plate but also of a thick composite plate with initial curvature. Flat composite specimens with various degrees of fiber waviness were fabricated and four-point flexural tests were conducted. The predicted nonlinear behavior by the current model was compared with results from the thin slice model [7] and experiments. Good agreement was observed among them.

Concurrent Engineering Design of Sheet Stamping by Using an Inverse FE Approach

1997 ◽  
Author(s):  
Shiyong Yang ◽  
Kikuo Nezu
Keyword(s):  
Finite Element ◽  
Concurrent Engineering ◽  
Process Simulation ◽  
Three Dimensional ◽  
Sheet Forming ◽  
Design Stage ◽  
Forming Process ◽  
Element Analysis ◽  
Preliminary Design Stage ◽  
Product And Process

Abstract An inverse finite element (FE) algorithm is proposed for sheet forming process simulation. With the inverse finite element analysis (FEA) program developed, a new method for concurrent engineering (CE) design for sheet metal forming product and process is proposed. After the product geometry is defined by using parametric patches, the input models for process simulation can be created without the necessity to define the initial blank and the geometry of tools, thus simplifying the design process and facilitating the designer to look into the formability and quality of the product being designed at preliminary design stage. With resort to a commercially available software, P3/PATRAN, arbitrarily three-dimensional product can be designed for manufacturability for sheet forming process by following the procedures given.

Finite Element Analysis of Stress Singularities in Attached Flip Chip Packages

2000 ◽  
Vol 122 (4) ◽  
pp. 301-305 ◽  
Author(s):  
A. Q. Xu ◽  
H. F. Nied
Keyword(s):  
Contact Angle ◽  
Finite Element ◽  
Glass Fiber ◽  
Flip Chip ◽  
Three Dimensional ◽  
Stress Singularity ◽  
Local Stress ◽  
Stress Singularities ◽  
Element Analysis ◽  
Three Dimensional Finite Element

Cracking and delamination at the interfaces of different materials in plastic IC packages is a well-known failure mechanism. The investigation of local stress behavior, including characterization of stress singularities, is an important problem in predicting and preventing crack initiation and propagation. In this study, a three-dimensional finite element procedure is used to compute the strength of stress singularities at various three-dimensional corners in a typical Flip-Chip assembled Chip-on-Board (FCOB) package. It is found that the stress singularities at the three-dimensional corners are always more severe than those at the corresponding two-dimensional edges, which suggests that they are more likely to be the potential delamination sites. Furthermore, it is demonstrated that the stress singularity at the upper silicon die/epoxy fillet edge can be completely eliminated by an appropriate choice in geometry. A weak stress singularity at the FR4 board/epoxy edge is shown to exist, with a stronger singularity located at the internal die/epoxy corner. The influence of the epoxy contact angle and the FR4 glass fiber orientation on stress state is also investigated. A general result is that the strength of the stress singularity increases with increased epoxy contact angle. In addition, it is shown that the stress singularity effect can be minimized by choosing an appropriate orientation between the glass fiber in the FR4 board and the silicon die. Based on these results, several guidelines for minimizing edge stresses in IC packages are presented. [S1043-7398(00)00904-X]

scholarly journals Accommodative Haptics Study Based on Flexible Amplification Mechanism

2020 ◽  
pp. 1-7
Author(s):  
Wenjing Wang ◽  
Qiuyue Du ◽  
Wenjing Chen ◽  
Bin Tian ◽  
Wenjing Wang
Keyword(s):  
Measurement Data ◽  
Theoretical Method ◽  
Structural Features ◽  
Stable Range ◽  
Element Analysis ◽  
Output Displacement ◽  
Amplification Ratio ◽  
Motion Trajectories ◽  
Bridge Type ◽  
Lens Power

In this study, we take the effect of the anterior movement of the optic into account and propose a novel haptic based on lever-type and bridge-type flexible amplification mechanisms. Based on the consideration of the offset of the rotation center of the flexible hinge, we have deduced the formula for calculating the amplification ratio of the proposed four-stage amplifier. The geometric parameters and the material property parameters, in terms of the clinical measurement data of the human eye, are assumed to restrain the structural features and motion trajectories for the amplifier. As the ciliary muscle achieves the contraction limit, the output displacement and amplification ratio reach the highest and lowest values, separately, and gradually approach a stable range. The amplification ratio of formula calculation and FEA (Finite Element Analysis) are around 18.86 and 17.79, respectively, with the input displacement ranging from 0.115mm to 0.127mm. The error of the amplification ratio between theoretical method and FEA is less than 5%. The presented haptic acting as a four-stage displacement amplifier, enables an improved lens power of 3.80 diopters to obtain much more focus shift to achieve a better near visual performance for patients.

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