Investigation of IMC Thickness Effect on the Lead-free Solder Ball Attachment Strength: Comparison between Ball Shear Test and Cold Bump Pull Test Results

Author(s):  
F. Song ◽  
S.W.R. Lee
Author(s):  
Jeffery Lo ◽  
Dennis Lau ◽  
S. W. Ricky Lee ◽  
Simon Chan ◽  
Frank Chan ◽  
...  

The solder ball shear test is a commonly used method to evaluate the attachment strength of solder balls. However, some previous studies indicated that the solder ball shear test may not be suitable for showing the effect of intermetallic compound (IMC) growth due to thermal aging. This is because the IMC layer is thin and not susceptible to the shear loading. Since the IMC layer consists of brittle materials, the ball pull test should be a better method to evaluate the solder ball attachment strength. The major challenge of conducting a solder ball pull test is how to grip the solder ball. This paper presents an innovative method for conducting the solder ball pull test. A shape memory alloy (SMA) tube is used to grip the solder ball and pull it off from the substrate. The inner diameter of the SMA tube is originally smaller than the diameter of the solder ball under testing. Once the temperature is raised to higher than the switching temperature of SMA, the SMA tube will expand radially, resulting an inner diameter larger than the solder ball. After the SMA tube cools down, the tube contracts and grips the solder ball firmly. The solder ball can then be pulled off from the attached substrate by frictional force. A prototype of the aforementioned solder ball pull test device has been developed. Some preliminary testing results are presented in this paper.


2005 ◽  
Vol 486-487 ◽  
pp. 269-272 ◽  
Author(s):  
Jong Woong Kim ◽  
Sun Kyu Park ◽  
Seung Boo Jung

Ball shear test was investigated in terms of the effects of important test parameter, i.e., shear height, with an experimental and non-linear finite element analysis for evaluating the solder joint integrity of area array packages. The substrate was a common SMD type with solder bond pad openings of 460 ㎛ in diameter. It was observed that increasing the shear height, at a fixed shear speed, has the effect of decreasing the shear force. The high shear height could cause some bad effects on the test results such as unexpected high standard deviation values or shear tip sliding from the solder ball surface. The low shear height conditions were favorable for screening the type of brittle interfacial fractures or the degraded layers in the interfaces.


Author(s):  
Vithyacharan Retnasamy ◽  
Zaliman Sauli ◽  
Phaklen Ehkan ◽  
Steven Taniselass

Author(s):  
Takahiro Kano ◽  
Ikuo Shohji ◽  
Tetsuyuki Tsuchida ◽  
Toshikazu Ookubo

An electroless Ni/Pd/Au plated electrode is expected to be used as an electrode material for lead-free solder to improve joint reliability. The aim of this study is to investigate the effect of the thickness of the Pd layer on joint properties of the lead-free solder joint with the electroless Ni/Pd/Au plated electrode. Solder ball joints were fabricated with Sn-3Ag-0.5Cu (mass%) lead-free solder balls and electroless Ni/Pd/Au and Ni/Au plated electrodes. Ball shear force and microstructure of the joint were investigated. The (Cu,Ni)6Sn5 reaction layer formed in the joint interface in all specimens. The thickness of the reaction layer decreased with increasing the thickness of the Pd layer. In the joint with a Pd layer 0.36 μm thick, the remained Pd layer was observed in the joint interface. In the joint, impact shear force decreased compared with that of the joint without the remained Pd layer. On the contrary, when the thickness of the Pd layer was less than 0.36 μm, the Pd layer was not remained in the joint interface and impact shear force improved. Impact shear force of the joint with the electroless Ni/Pd/Au plated electrode was higher than that with the electroless Ni/Au one.


2006 ◽  
Vol 417 (1-2) ◽  
pp. 259-274 ◽  
Author(s):  
Julian Yan Hon Chia ◽  
Brian Cotterell ◽  
Tai Chong Chai

Author(s):  
Akihiro Hirata ◽  
Ikuo Shohji ◽  
Tetsuyuki Tsuchida ◽  
Toshikazu Ookubo

The aim of this study is to investigate the joint properties of Sn-58mass%Bi and Sn-57mass%Bi-0.5mass%Sb low-melting lead-free solder balls on the electroless Ni/Au and Ni/Pd/Au plated Cu electrodes fabricated with a lead-free plating solution. Compared with the conventional Ni plating solution containing lead, the soldered joints with Ni/Au and Ni/Pd/Au electrodes fabricated with the lead-free plating solution showed comparable joint properties. In the joints with Ni/Pd/Au electrodes, ball shear force increased when the Pd layer is dissolved into solder by multi reflows. In both joints with Ni/Au and Ni/Pd/Au electrodes, a part of the Ni layer was dissolved into solder and thus the (Ni,Cu)3Sn4 intermetallic compound layer formed at the joint interface. Ball shear force decreased upon aging due to the growth of the (Ni,Cu)3Sn4 layer at the joint interface.


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