Solder Joint Formation in Surface Mount Technology—Part I: Analysis

1990 ◽  
Vol 112 (3) ◽  
pp. 210-218 ◽  
Author(s):  
S. M. Heinrich ◽  
A. F. Elkouh ◽  
N. J. Nigro ◽  
Ping S. Lee
Keyword(s):  
Solder Joint ◽  
Laboratory Data ◽  
Integral Form ◽  
Contact Angles ◽  
Reflow Process ◽  
Cross Sectional ◽  
Joint Formation ◽  
Surface Mount ◽  
Theoretical Predictions ◽  
Joint Shape

An analytical model of solder joint formation during a surface mount reflow process is developed in the present paper, and the solution is obtained in an explicit integral form. For two limiting cases—infinitesimal and infinite solder areas—the solution is expressed in closed form. Numerical results illustrate the influence of the process parameters (surface tension, density, and cross-sectional area of the molten solder, and the contact angles between the solder andpretinning) on joint shape and overall fillet dimensions. Comparisons between theoretical predictions and laboratory data show excellent agreement.

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.

Effect of Chip and Pad Geometry on Solder Joint Formation in SMT

1993 ◽  
Vol 115 (4) ◽  
pp. 433-439 ◽  
Author(s):  
S. M. Heinrich ◽  
P. E. Liedtke ◽  
N. J. Nigro ◽  
A. F. Elkouh ◽  
P. S. Lee
Keyword(s):  
Solder Joint ◽  
Printed Circuit Board ◽  
Integrated Approach ◽  
Contact Angles ◽  
Circuit Board ◽  
Zero Gravity ◽  
Cross Sectional ◽  
Board Density ◽  
Joint Formation ◽  
Maximum Utility

An analytical model of solder joint formation during a surface mount reflow process is developed for two-dimensional fillets whose flow may be restricted due to “finite” metallizations on a leadless component and the printed circuit board. Although these height and length constraints on the fillet geometry may result in obtuse contact angles, the solution is obtained in the form of an explicit integral, similar to that previously derived by the authors for the case of acute contact angles. This solution may also be recast into the form of elliptic integrals of the first and second kinds, thereby permitting one to evaluate the fillet geometry using mathematical tables or special function software, if desired, rather than resorting to a computer-based numerical quadrature. In addition an approximate zero-gravity solution is given by means of simple closed-form expressions relating the height, length, contact angles, and cross-sectional area of the fillet. Numerical results generated by implementing the “exact” integral solution for the joint profile are given in the form of dimensionless plots, relating fillet geometry to the solder properties (surface tension and density), amount of solder, chip height, and pad length. Also presented in dimensionless form are the approximate results from the zero-gravity model, which are independent of solder properties, yet are of sufficient accuracy for “small” joints. Because of their dimensionless nature, the results of the present paper may be of maximum utility to process engineers aiming to achieve desired joint geometries (e.g., to maximize fatigue life or to eliminate bridging problems), or to board designers responsible for selecting efficient footprint patterns to maximize board density. Models of solder joint formation, such as the one presented here, may be of most value when used in conjunction with stress analysis packages (e.g., finite element programs) and appropriate fatigue models. In this way an integrated approach to the design of solder joints and circuit boards may be taken, resulting in improved product reliability and performance.

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.

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.

Solder Joint Formation Simulation and Component Tombstoning Prediction During Reflow

1998 ◽  
Vol 120 (2) ◽  
pp. 141-144 ◽  
Author(s):  
X. Wu ◽  
X. Dou ◽  
C.-P. Yeh ◽  
K. Waytt
Keyword(s):  
Solder Joint ◽  
Model Simulation ◽  
Software Tool ◽  
Solder Paste ◽  
Reflow Process ◽  
Surface Evolver ◽  
Joint Formation ◽  
Geometry Design ◽  
Reliability Performance ◽  
Public Domain Software

The failure of electrical devices associated with solder joints has become one of the most critical reliability issues for surface-mounted devices. Solder joint reliability performance has been found to be highly dependent on the solder joint configuration, which, in turn, is governed by bond pad size, alloy material, and leadframe structure, as well as solder reflow characteristics. To investigate tombstone effects causing solder joint failure during leadless component reflow process, this work has focused on (1) developing a numerical model for the simulations of the solder joint formation during the reflow process, and (2) determining possibility that a tombstone effect for the leadless component may occur by analyzing the force and torque in the problem. Using this methodology, the tombstone effect associated with different pad geometry configurations and solder paste amount has been analyzed through the application of the public domain software tool Surface Evolver. Simulations show that the tombstoning is very sensitive to pad/component geometry design, solder surface tension, solder paste volume, wetting area, and wetting angle. This model simulation can be used to determine optimal solder paste volume, pad geometry configurations, and solder material for avoiding tombstone effects.

Kajian Kandungan Fe dalam Air Tanah Terhadap Kadar Ekskresi Yodium dalam Urin pada Anak Sekolah di Desa Cerme Kecamatan Panjatan Kabupaten Kulon Progo

2017 ◽  
Vol 19 (1) ◽  
pp. 7-11
Author(s):  
Vivi Linda Fristianti ◽  
Nur Hidayat ◽  
Slamet Iskandar
Keyword(s):  
Elementary School ◽  
Ground Water ◽  
School Children ◽  
Laboratory Data ◽  
Simple Random Sampling ◽  
Optimal Level ◽  
The Body ◽  
Design Data ◽  
Cross Sectional ◽  
Fe Content

Background : IDD problem is a serious problem, 33% of districts in Indonesia are endemic, 21% of endemic mild, moderate endemic 5% and 7% by weight endemic. Urine Iodine Excretion (EYU) illustrates the iodine intake of a person, because 90% of the iodine that enter the body are excreted through the urine. Blocking agents are substances certain minerals such as iron, manganese and calcium, which can bind iodine in groundwater. Objectives : This study aims to determine the relationship of Fe content in ground water sources against EYU levels in school children in the village of the District Cerme Panjatan Kulon Progo. Methods : An observational analytic research with cross sectional design. Data collection is done in May - June 2015. Location research Elementary School Cerme, District Panjatan Kulon Progo. The subjects of the study as many as 34 children in elementary school classroom Cerme 3, 4 and 5 were taken by simple random sampling. Well water and urine samples taken students then tested the iron in the Central Health Laboratory test Yogyakarta and iodine in urine in Magelang BP2GAKY Laboratory. Data analysis using Spearman Range test with significancy level : 0.05. Result : Fe content in the ground water is below the normal threshold is <0.3 mg / L. While levels EYU school children who are under the optimal level of 5.9%, the optimal level of 32.4%, and the optimum levels above 61.8% (optimal: 100 - 199μg / L). Conclusion : There was no significant relationship between the Fe content in groundwater with levels of EYU in school children in District Panjatan Kulon Progo (p = 0.447).   Keywords: Fe, EYU

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