Study on thermal simulation technology for SMA in lead-free reflow soldering

Author(s):  
Wu Zhaohua ◽  
Zhou Dejian
2013 ◽  
Vol 690-693 ◽  
pp. 2578-2582
Author(s):  
Wan Lei Liang ◽  
Xiao Dan Guan ◽  
Peng Zhao

Reflow soldering process parameters have distinct effect on the lead-free reflow profile and its key indicators. To determine the relationship between reflow soldering process parameters and lead-free reflow profile is significant for obtaining the correct reflow profile. The result of orthogonal experimental shows that the most influential factors of the change rate of heat-up RS are conveyor speed S, temperature set value of the heating zone 1 T1 and the temperature set value of heating zone 2 T2 in sequence; the most influential factors of the soaking time TS are conveyor speed S, the temperature set value of heating zone 4 T4 and the temperature set value of heating zone 2 T2 in sequence; the most influential factors of the reflow peak temperature PT are conveyor speed S, the temperature set value of heating zone 7 T7 and the temperature set value of heating zone 6 T6 in sequence; the most influential factors of the reflow time TAL are conveyor speed S and the temperature set value of heating zone 6 T6 in sequence.


2014 ◽  
Vol 602-605 ◽  
pp. 180-184
Author(s):  
Xuan Jun Dai ◽  
Hong Yan Huang

The reflow soldering process under infrared hot air environment was simulated based on a typical BGA SMA and a twelve-zone reflow oven. Then the optimal soldering process parameters were obtained based on 6σ analysis method and related software. The results could be used to direct the lead-free soldering process parameters setting, and the soldering quality was ensured effectively.


2016 ◽  
Vol 28 (2) ◽  
pp. 41-62 ◽  
Author(s):  
Chun Sean Lau ◽  
C.Y. Khor ◽  
D. Soares ◽  
J.C. Teixeira ◽  
M.Z. Abdullah

Purpose The purpose of the present study was to review the thermo-mechanical challenges of reflowed lead-free solder joints in surface mount components (SMCs). The topics of the review include challenges in modelling of the reflow soldering process, optimization and the future challenges in the reflow soldering process. Besides, the numerical approach of lead-free solder reliability is also discussed. Design/methodology/approach Lead-free reflow soldering is one of the most significant processes in the development of surface mount technology, especially toward the miniaturization of the advanced SMCs package. The challenges lead to more complex thermal responses when the PCB assembly passes through the reflow oven. The virtual modelling tools facilitate the modelling and simulation of the lead-free reflow process, which provide more data and clear visualization on the particular process. Findings With the growing trend of computer power and software capability, the multidisciplinary simulation, such as the temperature and thermal stress of lead-free SMCs, under the influenced of a specific process atmosphere can be provided. A simulation modelling technique for the thermal response and flow field prediction of a reflow process is cost-effective and has greatly helped the engineer to eliminate guesswork. Besides, simulated-based optimization methods of the reflow process have gained popularity because of them being economical and have reduced time-consumption, and these provide more information compared to the experimental hardware. The advantages and disadvantages of the simulation modelling in the reflow soldering process are also briefly discussed. Practical implications This literature review provides the engineers and researchers with a profound understanding of the thermo-mechanical challenges of reflowed lead-free solder joints in SMCs and the challenges of simulation modelling in the reflow process. Originality/value The unique challenges in solder joint reliability, and direction of future research in reflow process were identified to clarify the solutions to solve lead-free reliability issues in the electronics manufacturing industry.


2015 ◽  
Vol 60 (2) ◽  
pp. 1445-1448 ◽  
Author(s):  
D. Koncz-Horváth ◽  
G. Gergely ◽  
Z. Gácsi

Abstract In lead-free reflow soldering, the presence of voids should be taken into account. For this reason, the effect of the applied heating profiles was examined via the characterization of voids in galvanic and immersion Sn coatings. According to EU Directive 2002/95/EC, the screening of Pb element of reflow soldering (i.e. of electrical and electronic equipment) is necessary; and the practical implementation of this measurement is largely affected by the characteristics of the solder (i.e. the presence of voids and the inhomogeneity of the solder). Comparing the results of the above two coating methods, it was found that by chemical coating more voids were formed and the detected lead content was higher than for galvanic Sn. The standard deviation of Ag and Cu concentrations was mainly influenced by the appearance of large compounds in the second case, while with chemical coating, no large compounds were formed due to the elevated number of voids.


2012 ◽  
Vol 488-489 ◽  
pp. 1375-1379 ◽  
Author(s):  
O. Saliza Azlina ◽  
A. Ourdjini ◽  
I. Siti Rabiatull Aisha

Due to environmental concern, lead-free solder are taking the place of eutectic Sn-Pb solder in electronic packaging industry. Among various lead free alloys, Sn–Ag–Cu (SAC) alloys are leading lead-free candidate solders for various applications because it is offered better properties. This study investigates the interfacial reactions during reflow soldering and isothermal aging between Sn-3.0Ag-0.5Cu (SAC305) and Sn-3.0Ag-0.5Cu-0.05Ni (SACN30505) on electroless nickel/ immersion palladium/immersion gold (ENEPIG) surface finish. The substrates were subjected to isothermal aging at 125°C for up to 2000 hours with solder size diameter of 500μm. The results indicated that after reflow soldering, (Cu, Ni)6Sn5 IMC is formed between solder and substrate while after aging treatment a new IMC was formed between (Cu, Ni)6Sn5 and substrate known as (Ni, Cu)3Sn4. Moreover, after soldering and isothermal aging, Ni-doped (SACN) solder represents a thicker IMC compared to SAC solder. Aging time of solder joints results in an increase of IMC’s thickness and changes their morphologies to become more spherical, dense and with larger grain size. In addition, the results also revealed that the thickness of intermetallics formed is proportional to the aging duration.


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