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.

Optimum Gullwing Fillet Solder Joint Under Thermomechanical Forces

2004 ◽  
Vol 126 (1) ◽  
pp. 52-56 ◽  
Author(s):  
L. L. Meekisho ◽  
K. Nelson-Owusu
Keyword(s):  
Surface Tension ◽  
Solder Joint ◽  
Mechanical Response ◽  
Molten Solder ◽  
Reflow Process ◽  
Solder Joint Reliability ◽  
Gravitational Effects ◽  
Joint Reliability ◽  
Fillet Joint ◽  
Surface Tension Forces

The final shape of a solidified solder fillet joint from a reflow process is determined by process parameters and the solder alloy’s physical properties, including surface tension, density, gravity, and wetting angles. This work investigates the influence of surface tension at the solder-atmosphere interface; gravitational effects on the solder, and the influence of wetting angles on the mechanical response of the solder joint when subjected to thermomechanical loads. The predicted optimum fillet shape with minimum fillet area corresponded to the case where the ratio of gravity-to-surface tension forces is almost zero, and wetting angles, θ1 and θ2 being 90 deg. Results from this study suggest that, the influence of gravity on the molten solder geometry is negligible and hence can be assumed to be inconsequential to solder joint reliability issues.

Thermal Cycling Analysis of BGA Solder Joint Reliability

2012 ◽  
Vol 2012 (DPC) ◽  
pp. 000542-000553
Author(s):  
Betty H. Yeung ◽  
Torsten Hauck ◽  
Brett Wilkerson ◽  
Thomas Koschmieder
Keyword(s):  
Solder Joint ◽  
Thermal Cycling ◽  
High Reliability ◽  
Fatigue Behavior ◽  
Temperature Cycling ◽  
Fractional Factorial ◽  
Sphere Diameter ◽  
Surface Evolver ◽  
Solder Joint Reliability ◽  
Joint Reliability

The solder joint reliability of semiconductor package interconnects is critical to product durability. A dominant failure mode is solder fatigue due to the CTE mismatch between BGA component and PCB at thermal cycling. It is well known that besides thermal expansion mismatch of component and board, the solder joint geometry has a great impact on fatigue behavior and time to failure. In this study, a combination of Surface Evolver and finite element analysis are use to predict the solder joint shapes for the assembly of medium pin count BGA's and to estimate the reliability at accelerated temperature cycling conditions. Results of Surface Evolver are compared with the assumption of a truncated sphere. The solder shape predictions are applied for a subsequent thermo-mechanical analysis of the BGA assembly. Inelastic creep deformation is evaluated for critical solder balls, and the Coffin-Manson relation is used to estimate the solder joint lifetime. The entire simulation procedure will be demonstrated for a product design study for high reliability automotive BGA's. A fractional factorial design is defined that considers solder sphere diameter and solder pad sizes on BGA substrate and on PCB side. Resulting creep values and lifetime estimates will be compared.

Lead-On-Chip Versus Chip-On-Lead Packages and Solder Failure Criteria

2000 ◽  
Vol 122 (3) ◽  
pp. 279-280 ◽  
Author(s):  
Boris Mirman
Keyword(s):  
Solder Joint ◽  
Failure Criteria ◽  
High Impact ◽  
Solder Joint Reliability ◽  
Joint Reliability ◽  
On Chip

High impact of peeling stresses on solder joint reliability, and how to account for these stresses in failure criteria, are discussed. [S1043-7398(00)00803-3]

Effect of Reflow Process for Solder Joint Reliability of Electronic Packages

2002 ◽  
Vol 2002.6 (0) ◽  
pp. 273-274
Author(s):  
Hidehisa SAKAI ◽  
Qiang YU ◽  
Masaki SHIRATORI ◽  
Msanori MOTEGI
Keyword(s):  
Solder Joint ◽  
Electronic Packages ◽  
Reflow Process ◽  
Solder Joint Reliability ◽  
Joint Reliability

ENEP – A Cost-Effective Alternative for High Reliability Soldering Applications

2010 ◽  
Vol 2010 (DPC) ◽  
pp. 002190-002224
Author(s):  
Gustavo Ramos ◽  
Mustafa Oezkoek ◽  
Sven Lamprecht ◽  
Hugh Roberts
Keyword(s):  
Solder Joint ◽  
Surface Finish ◽  
High Reliability ◽  
Electroless Nickel ◽  
High Price ◽  
Nickel Layer ◽  
Nickel Surface ◽  
Solder Joint Reliability ◽  
Joint Reliability ◽  
Pure Palladium

Electroless nickel / immersion gold (ENIG) has been recognized within the electronics packaging industry as a reliable surface finish for soldering applications. Unlike surface finishes, such as OSP, immersion silver or immersion tin, which produce a Cu-Sn intermetallic upon soldering, the nickel layer of ENIG acts as a barrier to minimize copper dissolution during the soldering application. This function is especially important for assemblies that require multiple reflow steps. However, if not properly controlled, excessive corrosion of the nickel by the immersion gold step can also cause the well documented “black pad” effect, often resulting in solder joint reliability issues, including brittle fracture. As an alternative to ENIG, an electroless pure palladium layer over the electroless nickel (ENEP) provides a solderable surface without the noted risk of damage to the underling nickel layer. By eliminating the corrosive attack of the gold bath, the final layer stack would be suitable for high reliability soldering involving both IC substrate and PWB applications. In addition, because of the current high price of gold, replacing it with a pure palladium deposit can offer measureable cost savings for the ENEP process in comparison to ENIG. The paper summarizes an in-depth study of the effect on solder joint reliability caused by replacing the immersion gold by an electroless pure palladium layer. The study includes evaluations for both Pb-free (Sn-3.0Ag-0.5Cu) and eutectic SnPb (63Sn-37Pb) soldering applications. Results of investigations include: (1) cold ball pull testing to evaluate solder joint integrity, (2) SEM examinations of the underlying nickel surface, (3) IMC examinations to quantify nickel thickness degradation after multiple solder reflow cycles and (4) surface wetting through solder spread examinations. The paper discusses the relatively simple surface finish that, if proven effective in large-scale fabrication, may offer measureable performance and cost benefits in comparison to the more traditional ENIG finish.

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