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.

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.

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.

Thermal Aging Effect on the Ball Shear Strength of Pb-Free Solders on a Ceramic Substrate With Pd/Ag Surface Metallization

2000 ◽  
Author(s):  
Xing Jia Huang ◽  
Shi-Wei Ricky Lee ◽  
Wan Sze Tse
Keyword(s):  
Shear Strength ◽  
Thermal Aging ◽  
Aging Effect ◽  
Ceramic Substrate ◽  
Shear Tests ◽  
Ball Shear ◽  
Solder Balls ◽  
Surface Metallization ◽  
Free Solder ◽  
Ball Shear Strength

Abstract In the present study, solder balls of two Pb-free solder alloys, 95.5Sn-3.8Ag-0.7Cu and 91.8Sn-3.4Ag-4.8Bi, were reflowed on a ceramic substrate with the surface metallization of Pd/Ag. The specimens were subjected to thermal aging for 250 hours at the temperatures of 85°C, 125°C and 150°C, respectively. For comparison, specimens with 63Sn-37Pb solder were also fabricated and tested. Ball shear tests were performed to evaluate the effect of thermal aging on various solders. In general, the testing results indicated that the shear strength of solder balls decreased gradually with respect to the increase of thermal aging temperature. The shear strength of 95.5Sn-3.8Ag-0.7Cu solder balls was found to be least sensitive to the thermal aging. Besides, it was identified that the predominant failure mode in the ball shear tests was the fracture at the interface between the Pd/Ag metallization and the ceramic substrate.

The specific work of fracture in ball shear test and the integrity of solder balls

2006 ◽  
Vol 428 (1-2) ◽  
pp. 67-72 ◽  
Author(s):  
Julian Yan Hon Chia ◽  
Brian Cotterell ◽  
Augustine Yew Heng Cheong
Keyword(s):  
Shear Test ◽  
Specific Work ◽  
Ball Shear ◽  
Ball Shear Test ◽  
Solder Balls ◽  
Work Of Fracture ◽  
Specific Work Of Fracture
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