Solder Joint Shape Prediction Using a Modified Perzyna Viscoplastic Model

2004 ◽  
Vol 127 (3) ◽  
pp. 290-298 ◽  
Author(s):  
Mudasir Ahmad ◽  
Ken Hubbard ◽  
Mason Hu
Keyword(s):  
Surface Tension ◽  
Numerical Model ◽  
Solder Joint ◽  
Solder Joints ◽  
Element Analysis ◽  
Closed Form Solutions ◽  
Joint Construction ◽  
Shape Prediction ◽  
Applied Forces ◽  
Joint Shape

Ball grid array solder joint reliability is known to be dependent on the shape of solder joints after reflow. To ensure good solder joint formation and prevent solder bridging, it is critical to understand the amount of paste volume needed during assembly and reflow. The final shape of the solder joint is a function of surface tension, wetting area, gravity, and applied forces. In this paper, a new methodology to simulate solder joint shape is presented. Large deformation viscoplastic finite element analysis is used to simulate incompressible fluid flow. A numerical model for surface tension is outlined and validated with closed-form solutions. The results of the numerical model are compared to other known solder joint shape prediction methods. The effects of package weight, coplanarity, warpage, paste volume, pad misregistration, and joint construction on solder joint shape are then analyzed. Recommendations are provided on ways to maximize standoff height and avoid bridging. Finally, the formation of leadless solder joints is studied and compared to experimental data.

Study on the Conversion Method of Three-Dimensional Shape Prediction Model of BGA Solder Joints

2013 ◽  
Vol 706-708 ◽  
pp. 1693-1696
Author(s):  
Hua Bin Zhao ◽  
De Jian Zhou
Keyword(s):  
Solder Joints ◽  
Three Dimensional ◽  
Ball Grid Array ◽  
Analysis Software ◽  
Surface Evolver ◽  
Element Analysis ◽  
Shape Prediction ◽  
Dimensional Shape ◽  
Point Line ◽  
Three Dimensional Shape

In the study of three-dimensional shape prediction of SMT solder joints, the software Surface Evolver has been widely applied as a quick and accurate effective tool for the prediction of solder joints shape. But the model it builds is not able to be directly imported into any finite element analysis software like ANSYS, and even after the import it still needs a lot of time to mend the import model. For this issue, to predict of the solder joints shape of ball grid array (BGA), the implement programs of three conversion methods of point-line-area method, axisymmetric method and infinitesimal method are given. By comparison, axisymmetric method and infinitesimal method are more suitable for the shape conversion of BGA solder joints.

Reflow Process Simulation for Dispersion Evaluation of Solder Joint Shape on Chip Component

2009 ◽  
Author(s):  
Kanji Takagi ◽  
Qiang Yu ◽  
Tadahiro Shibutani ◽  
Hiroki Miyauchi
Keyword(s):  
Surface Tension ◽  
Solder Joint ◽  
High Reliability ◽  
Electronic Components ◽  
Reflow Process ◽  
Solder Joint Reliability ◽  
Automotive Electronic ◽  
Joint Reliability ◽  
On Chip ◽  
Joint Shape

The miniaturization and high reliability for automotive electronic components has been strongly requested. Generally, electronic component and printed wiring board are connected using solder joint. The reliability of solder joint has widely dispersion. For the dispersion reduction of solder joint reliability, not only design factors but manufacturing factors should be optimized. The evaluation of manufacturing factors for solder joint reliability was very difficult by experimental evaluation alone. Therefore, the reflow process simulation was established. The simulation was reenacted soldering process on chip component, which was the most severe reliability in automotive electronic components. The novelty of simulation was the coupled analysis of flow and rigid for simulating self-alignment of chip component. In this simulation, contact angle and surface tension was very important factor. So, these characteristics were measured based on Spread test and Wetting balance tests using the specimens. In the result, the solder joint shape of analysis was agree with the one of specimens using the measured contact angle and surface tension. Next, the effect of manufacturing process dispersion for solder joint shape was evaluated. The factors were mount offset and length unbalance of electrodes on chip component. As a result, the mount offset was not affected solder joint shape of chip component until a certain level. Also, the unbalance of electrode of chip component was not almost affected for solder joint shape of chip component because a part was moved to the center of part by surface tension of solder joint. Finally, the relation between the estimated solder joint shape and fatigue life of solder joints is evaluated using crack propagation analysis based on Manson-Coffin’s law and Miner’s rule. When the value of mount offset was large, the crack propagation mode was changed and the fatigue life of solder joint was decreased. As mentioned above, it was able to evaluate the relation between manufacturing factors and solder joint reliability. Accordingly, this simulation was very useful for consideration on the miniaturization, high reliability and appropriate margin for design of electronic components.

Solder Joint Formation in Surface Mount Technology—Part II: Design

1990 ◽  
Vol 112 (3) ◽  
pp. 219-222 ◽  
Author(s):  
S. M. Heinrich ◽  
N. J. Nigro ◽  
A. F. Elkouh ◽  
P. S. Lee
Keyword(s):  
Surface Tension ◽  
Solder Joint ◽  
Solder Joints ◽  
Cross Sectional Area ◽  
Surface Mount Technology ◽  
Sectional Area ◽  
Cross Sectional ◽  
Joint Formation ◽  
Surface Mount ◽  
Surface Tension Model

In this paper dimensionless design curves relating fillet height and length to joint cross-sectional area are presented for surface-mount solder joints. Based on an analytical surface tension model, the advantage of these dimensionless curves is that they may be used for arbitrary values of solder density and surface tension. The range of applicability of previously developed approximate formulae for predicting joint dimensions is also investigated. A simple example problem is included to illustrate the use of both the design curves and the approximate formulae.

A Two-Body Formulation for Solder Joint Shape Prediction

1998 ◽  
Vol 120 (3) ◽  
pp. 302-308 ◽  
Author(s):  
F. P. Renken ◽  
G. Subbarayan
Keyword(s):  
Solder Joint ◽  
Surface Area ◽  
Flip Chip ◽  
Contact Angles ◽  
Sessile Droplet ◽  
Solution Approach ◽  
Shape Prediction ◽  
Body Formulation ◽  
Wetted Surface Area ◽  
Joint Shape

Solder shape prediction is essential for accurate fatigue life determination and joint design optimization. In the present paper, a new solution approach using the surface tension theory is developed to simultaneously predict standoff height, wetted surface area, contact angles, and solder shape by including energy effects between a molten solder body and an arbitrarily shaped solid body. Existing models for solder shape prediction do not appear to determine all characteristics including joint standoff height, wetted surface area, and contact angles simultaneously. A general two-body axisymmetric finite element code is developed and coupled with a constrained optimizer to solve four illustrative examples. These examples include the shape of a sessile droplet on a fixed pad, a flip-chip joint, a sessile droplet on a free surface, and a typical ceramic ball grid array solder joint. In all four examples, the results predicted by the present approach compare favorably with available experimental and numerical results.

Micro Solder Joint Reliability and Warpage Investigations of Extremely Thin Double-layered Stacked-chip Packaging

2021 ◽  
Author(s):  
Chang-Chun Lee ◽  
Kuo-Shu Kao ◽  
Hou-Chun Liu ◽  
Chia-Ping Hsieh ◽  
Tao-Chih Chang
Keyword(s):  
Solder Joint ◽  
Solder Joints ◽  
Chip Thickness ◽  
Temperature Cycling ◽  
Nonlinear Material ◽  
Element Analysis ◽  
Fatigue Lifetime ◽  
Joint Reliability ◽  
Packaging Structure ◽  
Ic Package

Abstract To overcome the limited operational speed for nano-scaled transistors, scaling electronic devices to small and thin packaging and high-density arrangements have become the technological mainstream in designing versatile packaging architectures. Among these, a promising candidate is the 3D-IC package due to its excellent capability of heterogeneous integration. However, sequential reliability is a troublesome concern given the complex packaging structure, especially for the assembly of micro solder joints. To address this issue, we propose a double-layered, thin stacked chip package under the application of temperature cycling load. The packaging warpage and creep impact of SnAg micro solder joints on their fatigue lifespan are examined separately. Nonlinear material/geometry finite element analysis is used on important designed factors, including the elastic modulus of underfill, chip thickness, and the radius and pitch of through silicon via (TSV). The simulated results indicate that the best fatigue lifetime of SnAg micro solder joint can be achieved at 10 µm of each chip thickness, 230 and 5 µm for TSV pitch and radius within the examined designed extent. Moreover, a hard underfill material requires consideration when the mounted chips thicken. Consequently, reliability significantly improves by dispersing thermo-mechanical stress/strain of the SnAg microjoints to neighboring underfill and related packaging components, especially for large TSV array spacing.

Prediction of Equilibrium and Stability of Molten Solder Profiles by Finite Element Analysis

2002 ◽  
Author(s):  
Takahiro Nagata ◽  
Takaya Kobayashi ◽  
Hiroshi Sakuta
Keyword(s):  
Surface Tension ◽  
Solder Joint ◽  
Flip Chip ◽  
Deformation Analysis ◽  
Rigid Plastic ◽  
Element Analysis ◽  
Liquid Drops ◽  
Practical Applications ◽  
Updating Procedure ◽  
2D And 3D

In development of surface mount technology for Ball Grid Array (BGA) or flip-chip assemblies, it is important to reduce stress concentration in solder joints as it is immediately effective in improving the fatigue life of the assembly. Thus, the ability to predict and control the joint geometries is critical to obtaining robust and reliable designs of interconnects. Other than the issue of the bump shape, there are many problems concerning soldering such as bridging or self-alignment in which surface tension is definitely involved. This paper attempts to apply the FEM approach in solving these problems. Rigid-plastic FEM which is based on iteration for the velocity field in an incompressible viscous fluid is an approach to large deformation analysis. The flow stress is described by the viscosity of the fluid and the strain rate. By introducing an automatic mesh updating procedure, transient problems with free boundary can be treated. We applied this concept to the prediction of solder joint shapes. In this kind of problem, effects of surface tension dominate. Since surface tension is a distributed load that depends on surface curvature, we employed 2D and 3D methods in which the load is updated based on instantaneous state of surface. To verify the accuracy of this method, we analyzed some shape and stability problems of liquid drops for which theoretical solutions were given. Practical applications of the method were also performed for the 2D and 3D solder joint problems, and the results showed a good agreement with experimental ones.

scholarly journals The Effect of Epoxy Polymer Addition in Sn-Ag-Cu and Sn-Bi Solder Joints

Materials ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 960 ◽  
Author(s):  
Min-Soo Kang ◽  
Do-Seok Kim ◽  
Young-Eui Shin
Keyword(s):  
Solder Joint ◽  
Strain Energy ◽  
Printed Circuit Board ◽  
Solder Joints ◽  
Circuit Board ◽  
Solder Paste ◽  
Element Analysis ◽  
Printed Circuit ◽  
Shock Testing ◽  
Polymer Addition

To analyze the reinforcement effect of adding polymer to solder paste, epoxies were mixed with two currently available Sn-3.0Ag-0.5Cu (wt.% SAC305) and Sn-59Bi (wt.%) solder pastes and specimens prepared by bonding chip resistors to a printed circuit board. The effect of repetitive thermal stress on the solder joints was then analyzed experimentally using thermal shock testing (−40 °C to 125 °C) over 2000 cycles. The viscoplastic stress–strain curves generated in the solder were simulated using finite element analysis, and the hysteresis loop was calculated. The growth and propagation of cracks in the solder were also predicted using strain energy formulas. It was confirmed that the epoxy paste dispersed the stress inside the solder joint by externally supporting the solder fillet, and crack formation was suppressed, improving the lifetime of the solder joint.

A Procedure for Automated Shape and Life Prediction in Flip-Chip and BGA Solder Joints

1996 ◽  
Vol 118 (3) ◽  
pp. 127-133 ◽  
Author(s):  
G. Subbarayan
Keyword(s):  
Finite Element ◽  
Solder Joint ◽  
Life Prediction ◽  
Flip Chip ◽  
Solder Joints ◽  
Three Dimensional ◽  
Reliability Estimation ◽  
Element Mesh ◽  
Shape Prediction ◽  
Dimensional Finite Element

In this paper, a three-dimensional shape prediction model and a finite element solution procedure for flip-chip and BGA solder joints are developed. The developed system is capable of calculating the solder joint geometry and the fatigue life automatically without any intervention from the user. The automation achieved will enable fast reliability estimation and improved accuracy, since the two-dimensional finite element mesh used for solder shape prediction is used to generate the three-dimensional finite element mesh for stress analysis. The implementation of the procedure is verified using the solution for a flip-chip joint from literature, and the capability of the code is demonstrated on a hypothetical three-dimensional solder joint with square pads that are rotated with respect to each other, and offset from each other. The system developed in the study represents the first instance of an integrated, automated finite element procedure for both shape and fatigue life prediction in general three-dimensional solder joints. The automation achieved in the system enables fast reliability estimation in a design environment, and the optimal design of flip-chip and BGA solder joint configurations for maximum life.

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