Brittle Failure Mechanism of SnAgCu and SnPb Solder Balls during High Speed Ball Shear and Cold Ball Pull Tests

2007 ◽  
Author(s):  
Fubin Song ◽  
S. W. Ricky Lee ◽  
Keith Newman ◽  
Bob Sykes ◽  
Stephen Clark
Keyword(s):  
Failure Mechanism ◽  
Brittle Failure ◽  
High Speed ◽  
Ball Shear ◽  
Snpb Solder ◽  
Solder Balls ◽  
Pull Tests

Measurement of impact toughness of eutectic SnPb and SnAgCu solder joints in ball grid array by mini-impact tester

2008 ◽  
Vol 23 (5) ◽  
pp. 1482-1487 ◽  
Author(s):  
Yuhuan Xu ◽  
Shengquan Ou ◽  
K.N. Tu ◽  
Kejun Zeng ◽  
Rajiv Dunne
Keyword(s):  
Impact Toughness ◽  
High Speed ◽  
Solder Joints ◽  
Ball Grid Array ◽  
Snagcu Solder ◽  
Snpb Solder ◽  
Impact Tester ◽  
Pull Tests ◽  
The Impact ◽  
Eutectic Snpb

The most frequent cause of failure for wireless, handheld, and portable consumer electronic products is an accidental drop to the ground. The impact may cause interfacial fracture of ball-grid-array solder joints. Existing metrology, such as ball shear and ball pull tests, cannot characterize the impact-induced high speed fracture failure. In this study, a mini-impact tester was utilized to measure the impact toughness and to characterize the impact reliability of both eutectic SnPb and SnAgCu solder joints. The annealing effect at 150 °C on the impact toughness was investigated, and the fractured surfaces were examined. The impact toughness of SnAgCu solder joints with the plating of electroless Ni/immersion Au (ENIG) became worse after annealing, decreasing from 10 or 11 mJ to 7 mJ. On the other hand, an improvement of the impact toughness of eutectic SnPb solder joints with ENIG was recorded after annealing, increasing from 6 or 10 to 15 mJ. Annealing has softened the bulk SnPb solder so that more plastic deformation can occur to absorb the impact energy.

Effect of Solder Mask Thickness on Shear and Pull Tests of Lead-Free Solder Balls

2006 ◽  
Author(s):  
Fubin Song ◽  
S. W. Ricky Lee
Keyword(s):  
Shear Test ◽  
Shear Tests ◽  
Obvious Effect ◽  
Ball Shear ◽  
Pull Test ◽  
Ball Shear Test ◽  
Solder Balls ◽  
Solder Mask ◽  
Free Solder ◽  
Pull Tests

The present study is aimed at investigating the effect of solder mask thickness on the solder ball shear test. Compared to the ball pull test, less brittle failures were found in the ball shear test. This is most likely caused by the support of solder mask. So far there is not publication reporting the effect of solder mask in detail. In this paper, specimens with various thicknesses of solder mask were fabricated and a series of ball shear tests were conducted. Cold ball pull (CBP) tests were performed as well for parallel studies. The attachment strength of solder balls under multiple reflows was evaluated as an index for comparison. The test results indicate that, in ball shear tests, brittle failures can be identified more easily in specimens with thinner solder mask after multiple reflows, especially for tests with higher shear speed and more reflows. No obvious effect of solder mask thickness on the ball pull test was found, regardless of different pulling speeds and multiple reflows.

Predictive Failure Analysis of Solder Joints with Simultaneous High Speed EBSD and EDS

2018 ◽  
Author(s):  
J. Lindsay ◽  
P. Trimby ◽  
J. Goulden ◽  
S. McCracken ◽  
R. Andrews
Keyword(s):  
High Speed ◽  
Solder Joints ◽  
Phase Distribution ◽  
Bond Failure ◽  
Microstructural Parameters ◽  
Snpb Solder ◽  
Grain Orientations ◽  
Accelerated Thermal Cycling ◽  
The Relationship ◽  
Opening Up

Abstract The results presented here show how high-speed simultaneous EBSD and EDS can be used to characterize the essential microstructural parameters in SnPb solder joints with high resolution and precision. Analyses of both intact and failed solder joints have been carried out. Regions of strain localization that are not apparent from the Sn and Pb phase distribution are identified in the intact bond, providing key insights into the mechanism of potential bond failure. In addition, EBSD provides a wealth of quantitative detail such as the relationship between parent Sn grain orientations and Pb coarsening, the morphology and distribution of IMCs on a sub-micron scale and accurate grain size information for all phases within the joint. Such analyses enable a better understanding of the microstructural developments leading up to failure, opening up the possibility of improved accelerated thermal cycling (ATC) testing and better quality control.

Interfacial Microstructure Evolution Between Eutectic SnAgCu Solder and Al/Ni(V)/Cu Thin Films

2002 ◽  
Vol 17 (7) ◽  
pp. 1612-1621 ◽  
Author(s):  
M. Li ◽  
F. Zhang ◽  
W. T. Chen ◽  
K. Zeng ◽  
K. N. Tu ◽  
...  
Keyword(s):  
Thin Films ◽  
Phase Diagram ◽  
Solid State ◽  
Brittle Failure ◽  
Ternary Phase ◽  
Interfacial Microstructure ◽  
Snagcu Solder ◽  
Ball Shear ◽  
Aging Study ◽  
Eutectic Snpb

The evolution of interfacial microstructure of eutectic SnAgCu and SnPb solders on Al/Ni(V)/Cu thin films was investigated after various heat treatments. In the eutectic SnPb system, the Ni(V) layer was well protected after 20 reflow cycles at 220 °C. In the SnAgCu solder system, after 5 reflow cycles at 260 °C, the (Cu,Ni)6Sn5 ternary phase formed and Sn was detected in the Ni(V) layer. After 20 reflow cycles, the Ni(V) layer disappeared and spalling of the (Cu,Ni)6Sn5 was observed, which explains the transition to brittle failure mode after ball shear testing. The different interfacial reactions that occurred in the molten SnAgCu and SnPb systems were explained in terms of different solubilities of Cu in the two systems. The dissolution and formation of the (Cu,Ni)6Sn5phase were discussed on the basis of a Sn–Ni–Cu phase diagram. In the solid-state aging study of the SnAgCu samples annealed at 150 °C for up to 1000 h, the Ni(V) layer was intact and the intermetallic compound formed was Cu6Sn5 and not (Cu,Ni)6Sn5, which is the same as was observed for the eutectic SnPb system.

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