To simulate the formation of TSSOP solder joint with SAC solder and assess on the effects of the stencil design and the misalignment on the joint shape

2005 ◽  
Author(s):  
X.J. Zhao ◽  
J.F.J.M. Caers
Keyword(s):  
Solder Joint ◽  
Joint Shape ◽  
Sac Solder

Microstructure evolution observation for SAC solder joint: Comparison between thermal cycling and thermal storage

2009 ◽  
Vol 49 (9-11) ◽  
pp. 1267-1272 ◽  
Author(s):  
M. Berthou ◽  
P. Retailleau ◽  
H. Frémont ◽  
A. Guédon-Gracia ◽  
C. Jéphos-Davennel
Keyword(s):  
Solder Joint ◽  
Thermal Cycling ◽  
Microstructure Evolution ◽  
Thermal Storage ◽  
Sac Solder

Influence Of Solder Joint Shape On The Thermo-Mechanical Reliability Of CSP's

2004 ◽  
Vol 1 (2) ◽  
pp. 53-63 ◽  
Author(s):  
Co van Veen ◽  
Bart Vandevelde ◽  
Eric Beyne
Keyword(s):  
Solder Joint ◽  
Force Constant ◽  
Local Stress ◽  
Simulation Software ◽  
Temperature Cycling ◽  
Circuit Board ◽  
Surface Evolver ◽  
Joint Shape ◽  
Profile Estimation ◽  
Analytical Expressions

Not only the stand-off height but also the shape of a solder joint has a strong influence on the joint reliability under temperature cycling. The shape determines the size of the local stress and strain concentrations. It is therefore very important to know well the joint shape after reflow. In a previous paper closed analytical expressions were derived for liquid bump shapes, as a function of pad size and bump height [1]. The bump deformation as a function of the chip weight could be derived from the force constant. In the present paper closed analytical expressions are derived for the force constant for liquid bumps having unequal spherical pad sizes. It turns out that the force constant for compression can be optimized as a function of the ratio of those pad sizes. The shape of the bump and especially the contact angle is of interest for modeling activities where geometrical effects do play a role. Furthermore from the variation in bumps heights on a chip an estimate can be made of the tilt of the chip after assembly. The solder profile estimation by the analytical expressions is validated by experimental results. Also a comparison with the solder profile estimation by the simulation software Surface Evolver is done. Both comparisons showed that the analytical estimation of the standoff height is very good as long as the gravitation energy contributed by the chip weight is less than 10% of the total energy. Finally, an example is shown where the analytical model and Surface Evolver are the geometrical input for a finite element model. The example considers a CSP assembled at both sides of the printed circuit board.

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.

Package Tilt Prediction Using Surface Evolver

2007 ◽  
Author(s):  
Benjie B. Hornales ◽  
Erwin Ian V. Almagro
Keyword(s):  
Solder Joint ◽  
Visual Basic ◽  
Command Line ◽  
Surface Evolver ◽  
Joint Geometry ◽  
Joint Prediction ◽  
Joint Shape ◽  
User Friendly ◽  
Board Level ◽  
Data Surface

In board level package mounting process, many parameters will influence the final joint shape including the package stand-off height. If the stand-off height of solder joints at opposite ends does not equal, package tilting will occur. As a proactive measure to ascertain no tilting issues for newly develop packages, a methodology of predicting package tilting for BGA is developed using an energybased simulation model with surface evolver. The solder joint prediction model developed by Brakke proved to be very useful in predicting solder joint geometry after reflow and it will also be used to predict package tilting for BGA during board level mounting. This paper will discuss the capability of Surface Evolver in predicting solder joint geometry like solder ball height and diameter, and solder joint height. Then it moves on to discuss the methodology in using the same tool in predicting package tilting in board mounting process. It will be shown that the result of the surface evolver is well within the experimental data. Surface evolver program requires a command line input programming which is not very user-friendly, so a user interface was created using Visual Basic® 6 so that the engineer will only need to input relevant parameters into the program and command encoding is done automatically.

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.

A method of research for the reliability of solder joint shape

2021 ◽  
Author(s):  
Wenchao Tian ◽  
Xuewei Hou ◽  
Hao Cui ◽  
Xuegui Feng
Keyword(s):  
Solder Joint ◽  
Joint Shape

Mechanical Properties and Microstructure of Cu Core Solder Ball (CCSB) Compared with SAC305 Solder for 2.5D and 3D Structure Package (PKG)

2020 ◽  
Vol 12 (4) ◽  
pp. 556-563
Author(s):  
Jae-Yeol Son ◽  
Haksan Jeong ◽  
Seulgi Lee ◽  
Yeongwoo Lee ◽  
Seung-Boo Jung
Keyword(s):  
Mechanical Properties ◽  
Solder Joint ◽  
High Performance ◽  
3D Structure ◽  
Sac305 Solder ◽  
High Pressure And Temperature ◽  
Ball Surface ◽  
Solder Balls ◽  
2D Structure ◽  
Sac Solder

Package structures are continually becoming more complicated to achieve high-performance devices. Thus, the 2D structure of package needs to be modified to a 2.5D or 3D structure. Therefore, standoff properties at the solder joint are required to prevent Si chip damage and electrical shorts when the solder joint is located between the substrate and interposer. Cu-core solder balls (CCSB) are the most popular interconnection choice for a 2.5D package because they have better standoff properties than the general SAC solder. The mechanical properties of CCSBs were evaluated by ball shear tests and measuring bump height as compared with Sn–3.0 wt.%Ag–0.5 wt.% Cu solder. The bump heights of CCSBs and Sn–3.0 wt.%Ag–0.5 wt.% Cu were measured under several compressive pressure conditions at room temperature, 175 °C and 235 °C. The stand-off height of the CCSBs dramatically better than that of Sn–3.0 wt.%Ag–0.5 wt.% Cu solder under high pressure and temperature. The shear strength of the CCSBs was stronger than that of SAC solder at all multiple reflows due to the finer microstructure and higher stacking of dislocations at the interface of the Cu core ball surface.

Sign in / Sign up

Export Citation Format

Share Document