Grain structure evolution and its impact on the fatigue reliability of lead-free solder joints in BGA packaging assembly

Author(s):  
Huili Xu ◽  
Tae-Kyu Lee ◽  
Choong-Un Kim
Author(s):  
Doseop Kim ◽  
Qiang Yu ◽  
Yusuke Kobayashi ◽  
Tadahiro Shibutani

There have been serious debates about whether Pb should be removed from solder joints, in view of environmental problems. These debates have now developed to the extent that a remarkable movement to establish regulations for the removal of Pb has emerged, especially in European countries and Japan. Therefore, Many studies have been aggressively undertaken to develop technologies for replacing Sn-Pb solder with lead-free alternative. From the results obtained so far, it has been proven that the fatigue strength in lead-free solder joints is almost equivalent to the fatigue strength of Sn-Pb eutectic solder joints. However, a new problem is that voids are very easily formed in lead-free solder joints during the reflow process, and the effect of the voids on the fatigue strength of solder joints has attracted attention. In this study, the relationship between the voids and fatigue strength of solder joints was examined using mechanical shear fatigue test and FEM (finite element method) analysis. Using the mechanical shear fatigue test, the effect of the position and size of voids on fatigue crack initiation and crack propagation has been investigated. And quantitative evaluation of fatigue life of solder joints with the voids has been enabled by Manson-Coffin’s law and Miner’ rule.


2005 ◽  
Vol 46 (11) ◽  
pp. 2316-2321 ◽  
Author(s):  
Qiang Yu ◽  
Jae-Chul Jin ◽  
Do-Seop Kim ◽  
Masaki Shiratori

2017 ◽  
Vol 66 (4) ◽  
pp. 1229-1237 ◽  
Author(s):  
P. Wild ◽  
T. Grozinger ◽  
D. Lorenz ◽  
A. Zimmermann

2015 ◽  
Vol 772 ◽  
pp. 284-289 ◽  
Author(s):  
Sabuj Mallik ◽  
Jude Njoku ◽  
Gabriel Takyi

Voiding in solder joints poses a serious reliability concern for electronic products. The aim of this research was to quantify the void formation in lead-free solder joints through X-ray inspections. Experiments were designed to investigate how void formation is affected by solder bump size and shape, differences in reflow time and temperature, and differences in solder paste formulation. Four different lead-free solder paste samples were used to produce solder bumps on a number of test boards, using surface mount reflow soldering process. Using an advanced X-ray inspection system void percentages were measured for three different size and shape solder bumps. Results indicate that the voiding in solder joint is strongly influenced by solder bump size and shape, with voids found to have increased when bump size decreased. A longer soaking period during reflow stage has negatively affectedsolder voids. Voiding was also accelerated with smaller solder particles in solder paste.


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