Simulation of Effect of Solder Balls Layout on Warpage and Interfacial Stresses of FBGA

2012 ◽  
Vol 165 ◽  
pp. 334-338
Author(s):  
Chia Lung Chang ◽  
Li Chung Chen ◽  
Po Hsien Li
Keyword(s):  
Coefficient Of Thermal Expansion ◽  
The Finite Element Method ◽  
Interfacial Stresses ◽  
Sequential Processing ◽  
Die Attach ◽  
Fine Pitch ◽  
Processing Step ◽  
Solder Balls ◽  
Simulation Results ◽  
Processing Steps

The finite element method is used to construct the sequential processing model of the package. The model is used to simulate the warpage and interfacial stresses of FBGA (Fine-pitch Ball Grid Array) package due to the coefficient of thermal expansion mismatch between layered materials of package during assembly processes. The processing model uses the function of element birth and death to simulate the processing step of package model, considering the sequentially accumulated warpage and stresses during the processing steps. The induced package stresses can cause the delamination between die/die attach interface. In order to verify the simulation results, the simulated package warpage of a standard package is compared with the measurement of package warpage of the package. In this study, the effect of solder balls layout on the warpage and interfacial stresses at die/die attach interface is discussed by simulation results.

Effect of Material Properties and Thickness of Die Attach on Delamination of Die Attach/Die Paddle Interface in Electronic Package

2010 ◽  
Author(s):  
Chia-Lung Chang ◽  
Po-Hsien Li
Keyword(s):  
Material Properties ◽  
Coefficient Of Thermal Expansion ◽  
Damage Parameter ◽  
Stress And Strain ◽  
Thermal Expansion Mismatch ◽  
The Finite Element Method ◽  
Electronic Package ◽  
Die Attach ◽  
Encapsulation Process ◽  
Die Bonding

The electronic package is a multi-layered structure that is consisted of several materials. Under the temperature loadings, the interfacial stresses between layered components are generated due to the CTE (coefficient of thermal expansion) mismatch between different materials. In die bonding process, the void or defect might exist at the die attach/die paddle interface. The void cause further delamination on the interface during the encapsulation process. In this study, the finite element method is used to construct the model of electronic package with a void on the die attach/die paddle interface. The energy release rate based on J integration, which is calculated by the stress and strain around the tip of crack, is used as a damage parameter to predict the tendency of further delamination during encapsulation. Effect of material properties (Young’s modulus and CTE) and die attach thickness on delamination of die attach/die paddle interface in package during encapsulation is studied.

scholarly journals Reliability Evaluation of Fan-Out Type 3D Packaging-On-Packaging

Micromachines ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 295
Author(s):  
Pao-Hsiung Wang ◽  
Yu-Wei Huang ◽  
Kuo-Ning Chiang
Keyword(s):  
Finite Element ◽  
Thermal Cycling ◽  
Glass Substrate ◽  
High Speed ◽  
Coefficient Of Thermal Expansion ◽  
Three Dimensional ◽  
Design Parameters ◽  
Time To Failure ◽  
Wafer Level ◽  
Fine Pitch

The development of fan-out packaging technology for fine-pitch and high-pin-count applications is a hot topic in semiconductor research. To reduce the package footprint and improve system performance, many applications have adopted packaging-on-packaging (PoP) architecture. Given its inherent characteristics, glass is a good material for high-speed transmission applications. Therefore, this study proposes a fan-out wafer-level packaging (FO-WLP) with glass substrate-type PoP. The reliability life of the proposed FO-WLP was evaluated under thermal cycling conditions through finite element simulations and empirical calculations. Considering the simulation processing time and consistency with the experimentally obtained mean time to failure (MTTF) of the packaging, both two- and three-dimensional finite element models were developed with appropriate mechanical theories, and were verified to have similar MTTFs. Next, the FO-WLP structure was optimized by simulating various design parameters. The coefficient of thermal expansion of the glass substrate exerted the strongest effect on the reliability life under thermal cycling loading. In addition, the upper and lower pad thicknesses and the buffer layer thickness significantly affected the reliability life of both the FO-WLP and the FO-WLP-type PoP.

scholarly journals Secretion of Polypeptide Crystals from Tetrahymena thermophila Secretory Organelles (Mucocysts) Depends on Processing by a Cysteine Cathepsin, Cth4p

2015 ◽  
Vol 14 (8) ◽  
pp. 817-833 ◽  
Author(s):  
Santosh Kumar ◽  
Joseph S. Briguglio ◽  
Aaron P. Turkewitz
Keyword(s):  
Tetrahymena Thermophila ◽  
Secretory Granules ◽  
Content Type ◽  
Sequential Processing ◽  
Cysteine Cathepsin ◽  
Endoproteolytic Cleavage ◽  
Extracellular Stimuli ◽  
Peptide Secretion ◽  
Processing Steps

ABSTRACT In many organisms, sophisticated mechanisms facilitate release of peptides in response to extracellular stimuli. In the ciliate Tetrahymena thermophila , efficient peptide secretion depends on specialized vesicles called mucocysts that contain dense crystalline cores that expand rapidly during exocytosis. Core assembly depends of endoproteolytic cleavage of mucocyst proproteins by an aspartyl protease, cathepsin 3 ( CTH3 ). Here, we show that a second enzyme identified by expression profiling, Cth4p, is also required for processing of proGrl proteins and for assembly of functional mucocysts. Cth4p is a cysteine cathepsin that localizes partially to endolysosomal structures and appears to act downstream of, and may be activated by, Cth3p. Disruption of CTH4 results in cells (Δ cth4 ) that show aberrant trimming of Grl proproteins, as well as grossly aberrant mucocyst exocytosis. Surprisingly, Δ cth4 cells succeed in assembling crystalline mucocyst cores. However, those cores do not undergo normal directional expansion during exocytosis, and they thus fail to efficiently extrude from the cells. We could phenocopy the Δ cth4 defects by mutating conserved catalytic residues, indicating that the in vivo function of Cth4p is enzymatic. Our results indicate that as for canonical proteins packaged in animal secretory granules, the maturation of mucocyst proproteins involves sequential processing steps. The Δ cth4 defects uncouple, in an unanticipated way, the assembly of mucocyst cores and their subsequent expansion and thereby reveal a previously unsuspected aspect of polypeptide secretion in ciliates.

FEMLIB: An Object-Oriented Framework for Optimization and Simulation

1995 ◽  
Author(s):  
Michael M. Tiller ◽  
Jonathan A. Dantzig
Keyword(s):  
Material Properties ◽  
Object Oriented ◽  
The Finite Element Method ◽  
Simulation And Optimization ◽  
Gradient Based ◽  
Level Problem ◽  
Simulation Results ◽  
Optimization And Simulation ◽  
High Level ◽  
Simulation Parameters

Abstract In this paper we discuss the design of an object-oriented framework for simulation and optimization. Although oriented around high-level problem solving, the framework defines several classes of problems and includes concrete implementations of common algorithms for solving these problems. Simulations are run by combining these algorithms, as needed, for a particular problem. Included in this framework is the capability to compute the sensitivity of simulation results to the different simulation parameters (e.g. material properties, boundary conditions, etc). This sensitivity information is valuable in performing optimization because it allows the use of gradient-based optimization algorithms. Also included in the system are many useful abstractions and implementations related to the finite element method.

Modeling and Testing of Linear Electric Servo System

2012 ◽  
Vol 241-244 ◽  
pp. 1411-1417
Author(s):  
Xue Jiao Zhao ◽  
Fan Lin
Keyword(s):  
Data Collection ◽  
Data Processing ◽  
Servo System ◽  
Mathematic Model ◽  
Simulation Results ◽  
Processing Steps

A mathematic model of the electric servo system was founded in this paper and several groups of data collection and data processing were executed to check up the model veracity. This paper described the data processing steps and analyzed the contrast of test and simulation results. This model is effectual to describe the performance of this kind of servo in respect that the results are mainly consentaneous.

A Two Step Damage Prognosis Method for Beam-Like Truss Structures

2014 ◽  
Vol 578-579 ◽  
pp. 1092-1095
Author(s):  
Hao Kai Jia ◽  
Ling Yu
Keyword(s):  
Finite Element Method ◽  
Strain Energy ◽  
Truss Structure ◽  
Truss Structures ◽  
Second Step ◽  
The Finite Element Method ◽  
Modal Strain Energy ◽  
Damage Prognosis ◽  
Modal Curvature ◽  
Simulation Results

In this study, a two step damage prognosis method is proposed for beam-like truss structures via combining modal curvature change (MCC) with modal strain energy change ratio (MSECR). Changes in the modal curvature and the elemental strain energy are selected as the indicator of damage prognosis. Different damage elements with different damage degrees are simulated. In the first step, the finite element method is used to model a beam-like truss structure and the displacement modes are got. The damage region is estimated by the MCC of top and bottom chords of a beam-like truss structure. In the second step, the elemental MSECR in the damage region is calculated and the maximum MSECR element is deemed as the damage element. The simulation results show that this method can accurately locate the damage in the beam-like truss structure.

scholarly journals Investigation on Die Crack in a Stacked Die Package Using Finite Element Analysis

2021 ◽  
pp. 83-91
Author(s):  
Jefferson Talledo
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Coefficient Of Thermal Expansion ◽  
Crack Problem ◽  
Element Analysis ◽  
Robust Solution ◽  
Die Attach ◽  
Die Stress ◽  
Cte Mismatch ◽  
Semiconductor Packages

Die crack is one of the problems in stacked die semiconductor packages. As silicon dies become thinner in such packages due to miniaturization requirement, the tendency to have die crack increases. This study presents the investigation done on a die crack issue in a stacked die package using finite element analysis (FEA). The die stress induced during the package assembly processes from die attach to package strip reflow was analyzed and compared with the actual die crack failure in terms of the location of maximum die stress at unit level as well as strip level. Stresses in the die due to coefficient of thermal expansion (CTE) mismatch of the package component materials and mechanical bending of the package in strip format were taken into consideration. Comparison of the die stress with actual die crack pointed to strip bending as the cause of the problem and not CTE mismatch. It was found that the die crack was not due to the thermal processes involved during package assembly. This study showed that analyzing die stress using FEA could help identify the root cause of a die crack problem during the stacked die package assembly and manufacturing as crack occurs at locations of maximum stress. The die crack mechanism can also be understood through FEA simulation and such understanding is very important in coming up with robust solution.

Bi-Layered Model of Interfacial Thermal Stresses with the Effect of Different Temperatures in the Layers

2011 ◽  
Vol 87 ◽  
pp. 63-70 ◽  
Author(s):  
Sujan Debnath ◽  
Muhammad Ekhlasur Rahman ◽  
Woldemichael Dereje Engida ◽  
M. V. V. Murthy ◽  
K.N. Seetharamu
Keyword(s):  
Thermal Stresses ◽  
Physical Design ◽  
Temperature Gradients ◽  
Interfacial Stress ◽  
Stress Model ◽  
Interfacial Stresses ◽  
Linear Temperature ◽  
Layered Model ◽  
Die Attach ◽  
Different Temperatures

An interfacial shearing and peeling stress model is proposed to account for different uniform temperatures and thickness wise linear temperature gradients in the layers. This upgraded model can be viewed as a more generic form to determine interfacial stresses under different temperature conditions in a bi-layered assembly. The selected shearing and peeling stress results are presented for the case of die and die attach as commonly seen in electronic packaging. The obtained results can be useful in interfacial stress evaluations and physical design of bi-material assemblies, which are used in microelectronics and photonic applications.

scholarly journals Head-on-Pillow Defect Detection: X-Ray Inspection Limitations

2019 ◽  
Vol 16 (2) ◽  
pp. 91-102
Author(s):  
Lars Bruno ◽  
Benny Gustafson
Keyword(s):  
Solder Joints ◽  
Solder Paste ◽  
Wafer Level ◽  
Reflow Soldering ◽  
X Ray ◽  
Soldering Process ◽  
Irregular Shapes ◽  
Fine Pitch ◽  
Solder Balls ◽  
Ball Grid Array Packages

Abstract Both the number and the variants of ball grid array packages (BGAs) are tending to increase on network printed board assemblies with sizes ranging from a few millimeter die size wafer level packages with low ball count to large multidie system-in-package (SiP) BGAs with 60–70 mm side lengths and thousands of I/Os. One big challenge, especially for large BGAs, SiPs, and for thin fine-pitch BGA assemblies, is the dynamic warpage during the reflow soldering process. This warpage could lead to solder balls losing contact with the solder paste and its flux during parts of the soldering process, and this may result in solder joints with irregular shapes, indicating poor or no coalescence between the added solder and the BGA balls. This defect is called head-on-pillow (HoP) and is a failure type that is difficult to determine. In this study, x-ray inspection was used as a first step to find deliberately induced HoP defects, followed by prying off of the BGAs to verify real HoP defects and the fault detection correlation between the two methods. The result clearly shows that many of the solder joints classified as potential HoP defects in the x-ray analysis have no evidence at all of HoP after pry-off. This illustrates the difficulty of determining where to draw the line between pass and fail for HoP defects when using x-ray inspection.

Preliminary simulation analysis of the temperature fluctuation effect on Taiji-1 Laser interferometer

2021 ◽  
pp. 2140003
Author(s):  
Xiaoqin Deng ◽  
Ran Yang ◽  
Yu Niu ◽  
Keyword(s):  
Temperature Fluctuation ◽  
Laser Interferometer ◽  
Simulation Analysis ◽  
Optical Path Difference ◽  
Path Difference ◽  
Optical Simulation ◽  
The Finite Element Method ◽  
Fluctuation Noise ◽  
Fluctuation Amplitude ◽  
Simulation Results

Space-borne gravitational wave detection imposes a demanding requirement on the sensitivity of the laser interferometer. Among all disturbances that affect the measurement accuracy of the laser interferometer, temperature fluctuations contribute significantly. In this paper, the structure model and the interference path design of Taiji-1 laser interferometer have been used to conduct a preliminary simulation analysis of the temperature fluctuation noise through the finite element method. The temperature, the displacement and the optical path difference fluctuations have been obtained and theoretically analyzed. The preliminary simulation results are consistent with the theoretical analysis, which shows that the thermal–structural–optical simulation scheme adopted in this paper is reasonable. With the preliminary simulation results and the actual temperature control of Taiji-1 laser interferometer, we estimate that in Taiji-1 laser interferometer system, the temperature fluctuation is below the order of mK, the node displacement is within [Formula: see text][Formula: see text]pm, and the interference arm length difference fluctuation amplitude of the laser interferometer is also within [Formula: see text][Formula: see text]pm.

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