Impact of Isothermal Aging on the Long-Term Reliability of Fine-Pitch Ball Grid Array Packages With Different Sn-Ag-Cu Solder Joints

Abstract Both the number and the variants of ball grid array packages (BGAs) are tending to increase on network printed board assemblies with sizes ranging from a few millimeter die size wafer level packages with low ball count to large multidie system-in-package (SiP) BGAs with 60–70 mm side lengths and thousands of I/Os. One big challenge, especially for large BGAs, SiPs, and for thin fine-pitch BGA assemblies, is the dynamic warpage during the reflow soldering process. This warpage could lead to solder balls losing contact with the solder paste and its flux during parts of the soldering process, and this may result in solder joints with irregular shapes, indicating poor or no coalescence between the added solder and the BGA balls. This defect is called head-on-pillow (HoP) and is a failure type that is difficult to determine. In this study, x-ray inspection was used as a first step to find deliberately induced HoP defects, followed by prying off of the BGAs to verify real HoP defects and the fault detection correlation between the two methods. The result clearly shows that many of the solder joints classified as potential HoP defects in the x-ray analysis have no evidence at all of HoP after pry-off. This illustrates the difficulty of determining where to draw the line between pass and fail for HoP defects when using x-ray inspection.

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Impact of isothermal aging on fine pitch BGA packages with Sn-Ag-Cu solder interconnects

International Symposium on Microelectronics ◽

10.4071/isom-2010-tp4-paper3 ◽

2010 ◽

Vol 2010 (1) ◽

pp. 000298-000305

Author(s):

Tae-Kyu Lee ◽

Weidong Xie ◽

Thomas R. Bieler ◽

Kuo-Chuan Liu ◽

Jie Xue

Keyword(s):

Thermal Cycling ◽

Microstructure Evolution ◽

Isothermal Aging ◽

Substrate Surface ◽

Solder Interconnects ◽

Surface Finishes ◽

Bga Packages ◽

Fine Pitch ◽

Solder Balls

The interaction between isothermal aging and long-term reliability of fine pitch ball grid array (BGA) packages with Sn-3.0Ag-0.5Cu (wt%) solder ball interconnects are investigated. In this study, 0.4mm fine pitch packages with 0.3mm diameter Sn-Ag-Cu solder balls are used. Two different die sizes and two different package substrate surface finishes are selected to compare the internal strain impact and alloy effect, especially the Ni effect during thermal cycling. To see the thermal impact on the thermal performance and long-term reliability, the samples are isothermally aged and thermal cycled from 0 to 100°C with a 10minute dwell time. Based on weibull plots for each aging condition, the lifetime of the package reduced approximately 44% with 150°C aging precondition. The microstructure evolution is observed during thermal aging and thermal cycling with different phase microstructure transformations between electrolytic Ni/Au and OSP surface finishes, focusing on the microstructure evolution near the package side interface. Different mechanisms after aging at various conditions are observed, and their impacts on the fatigue life of solder joints are discussed.

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Impact of Conformal Coating Material on the Long-Term Reliability of Ball Grid Array Solder Joints

Procedia Manufacturing ◽

10.1016/j.promfg.2020.01.202 ◽

2019 ◽

Vol 38 ◽

pp. 1138-1142

Author(s):

Abid-Alrahman Fawzi Abbas ◽

Christopher M. Greene ◽

Krishnaswami Srihari ◽

Daryl Santos ◽

Ganesh Pandiarajan

Keyword(s):

Solder Joints ◽

Ball Grid Array ◽

Coating Material ◽

Conformal Coating

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Rapid Temperature Cycling (RTC) Methodology for Reliability Assessment of Solder Interconnection in Tape Ball Grid Array (TBGA) Assembly

Journal of Electronic Packaging ◽

10.1115/1.2056574 ◽

2005 ◽

Vol 127 (4) ◽

pp. 466-473 ◽

Cited By ~ 4

Author(s):

B. L. Chen ◽

X. Q. Shi ◽

G. Y. Li ◽

K. H. Ang ◽

Jason P. Pickering

Keyword(s):

Solder Joints ◽

Reliability Assessment ◽

Ball Grid Array ◽

Temperature Cycling ◽

Rapid Temperature ◽

Reliability Of Solder Joints ◽

Solder Joint Fatigue ◽

Time Required ◽

Failure Location

In this study, a thermoelectric cooler-based rapid temperature cycling (RTC) testing method was established and applied to assess the long term reliability of solder joints in tape ball grid array (TBGA) assembly. This RTC testing methodology can significantly reduce the time required to determine the reliability of electronic packaging components. A three-parameter Weibull analysis characterized with a parameter of failure free time was used for assembly reliability assessment. It was found that the RTC not only speedily assesses the long-term reliability of solder joints within days, but also has the similar failure location and failure mode observed in accelerated temperature cycling (ATC) test. Based on the RTC and ATC reliability experiments and the modified Coffin-Manson equation, the solder joint fatigue predictive life can be obtained. The simulation results were found to be in good agreement with the test results from the RTC. As a result, a new reliability assessment methodology was established as an alternative to ATC for the evaluation of long-term reliability of electronic packages.

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