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1.
Ye Tian Justin Chow Xi Liu Yi Ping Wu Suresh K. Sitaraman 《Journal of Electronic Materials》2013,42(2):230-239
With continued advances in microelectronics, it is anticipated that next-generation microelectronic assemblies will require a reduction of the flip-chip solder bump pitch to 100 μm or less from the current industrial practice of 130 μm to 150 μm. With this reduction in pitch size, and thus in bump height and diameter, the interaction between die pad metallurgy and substrate pad metallurgy becomes more critical due to the shorter diffusion path and greater stress. Existing literature has not addressed such metallurgical interaction in actual fine-pitch flip-chip assemblies. This work studies intermetallic growth and kinetics in fine-pitch lead-free solder bumps through thermal aging of flip-chip assemblies. Based on this study, it is seen that Ni from the die pad diffuses to the substrate pad region and Cu from the substrate pad diffuses to the die pad region, thus the resulting intermetallic compounds at the die and substrate pad regions are influenced by the other pad as well. Such cross-pad interaction is much stronger in fine-pitch solder bumps with smaller standoff height. It is seen that the die pad region contains Ni3P and (Cu,Ni)6Sn5 after thermal aging, while the substrate pad region contains Cu3Sn and (Cu,Ni)6Sn5. By digitally measuring the thickness of the interfacial phases, the kinetics parameters and the activation energy were calculated for the growth of (Cu,Ni)6Sn5 on the substrate side. The Cu diffusion coefficient through the intermetallic compound (IMC) layer was found to be 0.03370 μm2/h, 0.1423 μm2/h, and 0.4463 μm2/h at 100°C, 125°C, and 150°C, respectively, and the apparent activation energy for the growth of compound layers was 67.89 kJ/mol. 相似文献
2.
Ye Tian Xi Liu Justin Chow Yi Ping Wu Suresh K. Sitaraman 《Journal of Electronic Materials》2013,42(8):2724-2731
The intermetallic compound (IMC) evolution in Cu pad/Sn-Ag-Cu solder interface and Sn-Ag-Cu solder/Ni pad interface was investigated using thermal shock experiments with 100-μm-pitch flip-chip assemblies. The experiments show that low standoff height of solder joints and high thermomechanical stress play a great role in the interfacial IMC microstructure evolution under thermal shock, and strong cross-reaction of pad metallurgies is evident in the intermetallic growth. Furthermore, by comparing the IMC growth during thermal aging and thermal shock, it was found that thermal shock accelerates IMC growth and that kinetic models based on thermal aging experiments underpredict IMC growth in thermal shock experiments. Therefore, new diffusion kinetic parameters were determined for the growth of (Cu,Ni)6Sn5 using thermal shock experiments, and the Cu diffusion coefficient through the IMC layer was calculated to be 0.2028 μm2/h under thermal shock. Finite-element models also show that the solder stresses are higher under thermal shock, which could explain why the IMC growth is faster and greater under thermal shock cycling as opposed to thermal aging. 相似文献
3.
电子封装使用多种性能各异的材料,这些材料的热膨胀系数各不相同.把其组合成一个整体后,当温度变化时,在不同的材料界面会产生压缩或拉伸应力.建立了完全焊点阵列形式的模型,采用局部温度加载方式,对塑料球栅阵列封装的热应力进行了数值模拟. 相似文献
4.
CGA(陶瓷栅格阵列)封装件由于具有良好的散热性、高可靠性等优势,在军事、航天领域的应用正不断增多.从CGA件的封装结构、设计尺寸到装焊工艺进行了介绍和分析,对装配过程中的难点、关键点作出了说明和探讨. 相似文献
5.
Tae-Kyu Lee 《Journal of Electronic Materials》2013,42(4):599-606
The interaction between electrical current and the long-term reliability of fine-pitch ball grid array packages with Sn-3.0Ag-0.5Cu (wt.%) solder ball interconnects is investigated. In this study, 0.4-mm fine-pitch packages with 300-μm-diameter Sn-Ag-Cu solder balls are used. Electrical current was applied under various conditions to two different package substrate surface finishes to compare the effects of chemically unmixed and mixed joint structures: a Cu/SAC305/Cu structure and a NiAu/SAC305/Cu structure, respectively. To study the thermal impact on the thermal fatigue performance and long-term reliability, the samples were thermally cycled from 0°C to 100°C with and without current stressing. Based on Weibull plots, the characteristic lifetime was degraded for the mixed joint structure, but little degradation was observed for the unmixed joint structure. The microstructure evolution was observed during constant current stressing and current stressing during thermal cycling. Accelerated intermetallic precipitation depletion at the package-side interface was observed in NiAu/SAC305/Cu structures due to current stressing, which was identified as the potential reason for the degradation in the thermal cycling performance. 相似文献
6.
Chong D.Y.R. Che F.X. Pang J.H.L. Luhua Xu Xiong B.S. Toh H.J. Lim B.K. 《Advanced Packaging, IEEE Transactions on》2008,31(1):66-75
Board-level drop testing is an effective method to characterize the solder joint reliability performance of miniature handheld products. In this study, drop test of printed circuit boards (PCBs) with a four-screw support condition was conducted for a 15 mm times 15 mm fine-pitch ball grid array (FBGA) package assembly with solder ball compositions of 36Pb-62Sn-2Ag and Sn-4Ag-0.5Cu on printed circuit board (PCB) surface finishes of organic solderability preservative, electroless nickel immersion gold, and immersion tin. Finite element modeling of the FBGA assembly was performed to study the stress-strain behavior of the solder joints during drop test. The drop test results revealed a strong influence of different intermetallic compound formation on soldered assemblies drop durability. The lead-based solder supersedes the lead-free composition regardless of the types of surface finish. Joints on organic solderability preservative were found to be strongest for each solder type. Other factors affecting drop reliability such as component location on the board and thermal cycling aging effects are reported. Finite element modeling results showed that a solder joint is more prone to failure on the PCB side, and the predicted solder joint stresses are location dependent. Predicted failure sites based on simulation results are consistent with experimental observations. 相似文献
7.
球栅阵列技术已经激起了电子行业的人们强烈的兴趣。随着人们的目光愈来愈多地关注于BGA器件的组装的时候,对BGA器件进行组装时所产生的清洗和干燥的问题受到了人们广泛的关注,各种各样的BGA器件和焊膏需要采用合适的清洗处理方法。 相似文献
8.
Tae-Kyu Lee Weidong Xie Bite Zhou Thomas Bieler Kuo-Chuan Liu 《Journal of Electronic Materials》2011,40(9):1967-1976
The interaction between isothermal aging and long-term reliability of fine-pitch ball grid array (BGA) packages with two
different die sizes was investigated. Both 5 mm × 5 mm and 10.05 mm × 10.05 mm die-attached packages with Sn-3.0Ag-0.5Cu (wt.%)
solder balls were used to compare the correlation between the internal strain difference and isothermal aging on microstructural
evolution during thermal cycling. To determine their long-term reliability, the samples were isothermally aged and thermally
cycled from 0°C to 100°C with 10-min dwell time. Based on Weibull plots for each aging condition, the packages with large
dies attached showed shorter characteristic lifetimes, because of the relatively higher stress, but showed less lifetime degradation
with isothermal aging compared with the smaller die-attached samples. Microstructure analysis using orientation imaging microscopy
(OIM) revealed the evolution of the microstructure during thermal cycling, showing a higher degree of recrystallization inside
the bulk solder for joints that were isothermally aged and experienced higher stress. The possible mechanisms giving rise
to these observations are discussed. 相似文献
9.
The interaction between isothermal aging and the long-term reliability of fine-pitch ball grid array (BGA) packages with Sn-3.0Ag-0.5Cu
(wt.%) solder ball interconnects was investigated. In this study, 0.4-mm fine-pitch packages with 300-μm-diameter Sn-Ag-Cu solder balls were used. Two different package substrate surface finishes were selected to compare their
effects on the final solder composition, especially the effect of Ni, during thermal cycling. To study the impact on thermal
performance and long-term reliability, samples were isothermally aged and thermally cycled from 0°C to 100°C with 10 min dwell
time. Based on Weibull plots for each aging condition, package lifetime was reduced by approximately 44% by aging at 150°C.
Aging at 100°C showed a smaller impact but similar trend. The microstructure evolution was observed during thermal aging and
thermal cycling with different phase microstructure transformations between electrolytic Ni/Au and organic solderability preservative
(OSP) surface finishes, focusing on the microstructure evolution near the package-side interface. Different mechanisms after
aging at various conditions were observed, and their impacts on the fatigue lifetime of solder joints are discussed. 相似文献
10.
Lei Nie Maik Mueller Michael Osterman Michael Pecht 《Journal of Electronic Materials》2010,39(8):1218-1232
In this study, ball grid array (BGA) packages with Sn-3.0Ag-0.5Cu (SAC305) solder balls were reballed with Sn-37Pb solder
balls. Three different reballing methods were used. The non-reballed lead-free BGAs were assembled with SAC305 and Sn-37Pb
solder pastes to form the lead-free and mixed assemblies. The reballed Sn-Pb BGAs were assembled with Sn-37Pb solder paste
to form the reballed Sn-Pb assemblies. All assemblies were subjected to a temperature cycling test with a temperature range
of −55°C to 125°C. For the same component type, the reballed BGA assemblies showed similar temperature cycling reliability
regardless of the reballing methods. However, the temperature cycling reliability of the reballed assemblies was worse than
that of the mixed and the lead-free assemblies. The mean cycles-to-failure of the mixed assemblies was larger than or equal
to that of the lead-free assemblies. Failure analysis revealed that the failure site in reballed Sn-Pb assemblies was located
in the bulk solder at the component side regardless of the component type and the reballing method, indicating that the reballing
method did not influence the crack propagation in reballed assemblies. The mixed assemblies had the same failure site as the
lead-free assemblies, i.e., in the bulk solder at the component side. The microstructure differences between the tin-lead,
lead-free, and mixed assemblies are also discussed in detail. 相似文献
11.
BGA器件不仅能够满足现在已有的其它组件所不能够提供的高性能、大量I/O数量的应用要求,也给如今的有引脚元器件提供了一种可靠的可替换方案。对于在组件体的底部位置安置有大量焊球阵列的BGA器件来说有四种主要的类型。表面阵列配置的组装技术将会成为电子组装业最主要的发展潮流。 相似文献
13.
近年来,许多国家禁止在电子产品中铅的使用,但是一些特定产品拥有豁免权。拥有豁免权的电子产品生产厂商面临含铅元器件供应缺乏的现状,因此生产厂商开始寻求利用焊球再成形技术把焊球阵列封装中的无铅焊球转变为锡铅焊球。焊球再成形技术曾经被用于元器件的回收再利用,但是关于焊球再成形元器件的可靠性信息十分有限。介绍了利用焊球再成形技术使无铅焊球阵列封装转变为锡铅焊球阵列封装。两种焊球去除方法和两种焊球再贴装方法分别用于实现从无铅焊球到锡铅焊球的转变,用以调查再成形工艺对于封装质量的影响。热时效试验以及焊球强度评估用于检测焊球再成形工艺过程。 相似文献
14.
Lei Nie ;Michael Osterman ;Michael Pecht ;Fubin Song ;Jeffrey Lo ;S.W. Ricky Lee 《电子工业专用设备》2009,(2):1-5
近年来,许多国家禁止在电子产品中铅的使用,但是一些特定产品拥有豁免权。拥有豁免权的电子产品生产厂商面临含铅元器件供应缺乏的现状,因此生产厂商开始寻求利用焊球再成形技术把焊球阵列封装中的无铅焊球转变为锡铅焊球。焊球再成形技术曾经被用于元器件的回收再利用.但是关于焊球再成形元器件的可靠性信息十分有限。介绍了利用焊球再成形技术使无铅焊球阵列封装转变为锡铅焊球阵列封装。两种焊球去除方法和两种焊球再贴装方法分别用于实现从无铅焊球到锡铅焊球的转变,用以调查再成形工艺对于封装质量的影响。热时效试验以及焊球强度评估用于检测焊球再成形工艺过程。 相似文献
15.
《Components and Packaging Technologies, IEEE Transactions on》2009,32(4):901-908
16.
《Components and Packaging Technologies, IEEE Transactions on》2009,32(1):12-19
17.
18.
PBGA封装的可靠性研究综述 总被引:1,自引:0,他引:1
杨建生 《电子产品可靠性与环境试验》2004,(1):53-57
通过传统BT类型的PWB材料与独特的PWB材料来PBGA封装的可靠性。相关的研究结果表明,后者同样具有相同的热循环稳定性和回流焊期间的疲劳强度,并具有较低的封装翘曲特点;模塑料的低吸湿性及粘片材料的高粘附强度和高断裂强度特性,有利于提高回流焊期间的疲劳强度和防止剥离现象的扩散。 相似文献
19.
建立了倒装陶瓷球栅阵列(flip chip ceramic ball grid array,FC-CBGA)封装的三维热模型。在5 W热负荷下,比较了裸芯片式、盖板式和盖板加装热沉三种情况下芯片的热性能,进而分析了有无热沉和不同空气流速下,盖板式封装的具体热流分配情况。结果表明:在自然对流下,与裸芯片式相比,采用盖板式能使芯片结点温度降低约16℃,盖板加装热沉能使芯片结温降低47℃。芯片产生的热量大部分向上流向盖板,且随着空气流速的增加比例增大;由芯片流向盖板的热量有相当大一部分经过侧面流向基板,且随着流速增大比例较小。 相似文献