Effects of Tooling Tip Wear and Fixture Rigidity on Solder Ball Shear and Ball Pull Tests

2007 ◽  
Author(s):  
Fubin Song ◽  
S. W. Ricky Lee
Keyword(s):  
Shear Test ◽  
Failure Modes ◽  
Progressive Failure ◽  
Rigid Plate ◽  
Ball Shear ◽  
Pull Test ◽  
Pull Strength ◽  
Ball Shear Test ◽  
Significant Difference ◽  
Pull Tests

The present study is aimed at evaluating the effect of ball shear tool wear and fixture rigidity on ball shear and ball pull tests respectively. In particular, the emphasis is placed on understanding the progressive failure mechanism during the ball shear test. The location of crack initiating is investigated on two kinds of shear tool with different wear features. In this paper, the experimental investigation is presented. Specimens with PBGA solder balls are fabricated and a series of ball shear and pull tests are conducted. In the shear test, the shear tool is stopped at a certain stage during test, and then the specimens are inspected by SEM. The failure modes and location of cracks are characterized. From the ball attachment strength and crack location of the ball shear test, no significant difference is found between the shear tools with different wear features. For investigating the effect of fixture rigidity on the ball pull test, two kinds of PBGA package with different sizes was fixed on the fixtures with and without gluing on a rigid plate. The failure modes and ball pull strength with different fixture rigidity were compared. The test results indicate that more brittle failures are found on the specimens without gluing on the rigid plate during the ball pull test, both on two kinds of package with different sizes. In addition, the data scattering of ball pull strength is large on the case without gluing on rigid plate.

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.

A New Method for the Solder Ball Pull Test Using a Shape Memory Alloy Tube

2004 ◽  
Author(s):  
Jeffery Lo ◽  
Dennis Lau ◽  
S. W. Ricky Lee ◽  
Simon Chan ◽  
Frank Chan ◽  
...  
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Shear Test ◽  
Solder Ball ◽  
Shear Loading ◽  
Ball Shear ◽  
Pull Test ◽  
Ball Shear Test ◽  
Attachment Strength ◽  
Inner Diameter

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.

Mechanical Property Evaluation of Sn-3.0A-0.5Cu BGA Solder Joints Using High-Speed Ball Shear Test

2009 ◽  
Vol 38 (12) ◽  
pp. 2489-2495 ◽  
Author(s):  
Sang-Su Ha ◽  
Jin-Kyu Jang ◽  
Sang-Ok Ha ◽  
Jong-Woong Kim ◽  
Jeong-Won Yoon ◽  
...  
Keyword(s):  
Mechanical Property ◽  
High Speed ◽  
Shear Test ◽  
Solder Joints ◽  
Ball Shear ◽  
Property Evaluation ◽  
Ball Shear Test

The mechanics of the solder ball shear test and the effect of shear rate

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

scholarly journals Effect of Structural Design Parameters on Wafer Level CSP Ball Shear Strength and Their Influence on Accelerated Thermal Cycling Reliability

2009 ◽  
Author(s):  
Nikhil Lakhkar ◽  
Puligandla Viswanadham ◽  
Dereje Agonafer
Keyword(s):  
Thermal Cycling ◽  
Shear Test ◽  
Solder Ball ◽  
Wafer Level ◽  
Ball Shear ◽  
Ball Size ◽  
Ball Shear Test ◽  
Accelerated Thermal Cycling ◽  
Ball Shear Strength ◽  
Board Level

Ball shear testing is typically conducted in Wafer level chip scale package (WLCSP) fabrication to estimate the strength of the solder ball attachment. Generally, the solder ball shear strength is dependent on the solder ball size, pad size, solder/pad interface treatment, reflow temperature and time. Solder ball strength is also a function of ram speed and height at which the ball is sheared with respect to the wafer. Recent investigations suggest that ball shear test is being used as an indicator for board level reliability of assemblies. In current market lead time for launching a new product is very short. Unfortunately, it takes several weeks to qualify a new product by board level qualification process. If there is a methodology through which one can predict the board level performance by extrapolating the wafer level test, it will save great amount of resources in testing and millions of dollars worth of testing time. In the first part of this study, we conducted a wafer level ball shear test. A DOE was created for varying wafer level structural parameters like solder ball size and type. Ball shear tests and Accelerated thermal cycling have similar failure signatures of compression on inner side and tension on outer side. Thus, for specific cases there is a possibility of correlating the two failure methodologies based on their failure signatures. Strain rate for ball shear test was determined based on shear speed and solder pad diameter. Strain rate for accelerated thermal cycling was determined based on difference in CTE between board and package. In this paper, results from ball shear test and accelerated thermal cycling are compared to find correlations for specific cases. The correlations derived from this study are statistical and empirical.

scholarly journals The Influence of Recycling on the Properties of Interface between Ceramic and Dental Alloys

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Yinghui Wang ◽  
Honglan Huang ◽  
Honglei Lin ◽  
Lei Jiang ◽  
Yu Pan ◽  
...  
Keyword(s):  
Bond Strength ◽  
Thermal Cycling ◽  
Shear Test ◽  
Failure Modes ◽  
Dental Alloys ◽  
Exact Probability ◽  
Interfacial Morphology ◽  
Significant Difference ◽  
Metal Ceramic ◽  
Pt Alloys

Statement of Problem. Results are discrepant regarding the metal-ceramic interface of dental alloys affected by recycling. Purpose. The purpose of this study was to evaluate the effect of recycling on the properties of interface between 2 dental alloys and their corresponding porcelains. Materials and Methods. Noble alloy (Pd-Cu-Ga) and high-noble alloy (Au-Pt) were used in this study. Metal matrices (cylinders Φ4 mm×4 mm with pedestal Φ5 mm×1 mm) were prepared by arc melting in argon after recasting 1-3 times. Corresponding porcelain with overall dimensions of Φ4 mm×2 mm was veneered on each metal cylinder. There were 22 specimens in each alloy group. Specifically, two specimens of each group were chosen randomly for interfacial morphology and diffusion analyses by scanning electron microscopy (SEM) equipped with energy-dispersive X-ray spectroscopy (EDS). The remaining 20 specimens were divided into 2 groups with or without thermal cycling. The bond strength was evaluated by shear test, and the data were analyzed by two-way analysis of variance (ANOVA). The failure mode of shear test specimen was observed with a stereoscopic microscopy and subjected to the exact probability test (α=0.05). Results. According to the results from SEM, no obvious difference was observed in the interfacial morphology of both Pd-Cu-Ga and Au-Pt alloys among different recasting specimens. EDS analysis revealed that no significant difference was found in the width of elemental diffusion among 2 test alloys after recycling 1-3 times. Notably, in Pd-Cu-Ga alloy groups, the peak of Ga in thrice recasting was lower than those in first and second recastings. And there was no significant difference (P>0.05) in the metal-ceramic shear bond strength of Pd-Cu-Ga and Au-Pt alloys after recycling 1-3 times, with or without thermal cycling. The results of failure modes observed on specimens were not affected by the recycling and thermal cycling in the 2 tested alloys. Conclusions. Within the limitations of this study, the Pd-Cu-Ga and Au-Pt alloys can be recycled 2 times without significant changes on the properties of metal-ceramic interface, with or without thermal cycling.

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