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1.
Experimental study on the thermo-mechanical effects of underfill and low-CTE substrate in a flip-chip device 总被引:1,自引:0,他引:1
Yasuyuki Morita Kazuo Arakawa Mitsugu Todo Masayuki Kaneto 《Microelectronics Reliability》2006,46(5-6):923-929
Moiré interferometry was used to analyze the thermal deformation of four flip-chip devices mounted on FR-4 substrate and a new multi-layer substrate, with and without underfill. Thermal loading was applied by cooling the devices from 100 °C to room temperature (25 °C). The effects of underfill and the low-CTE (coefficient of thermal expansion) substrate on thermal deformation were investigated. The experimental results showed that the underfill curved in a manner similar to the silicon chip. For the flip-chip devices mounted on the multi-layer substrate, the CTE mismatch between the silicon chip and substrate was reduced, and bending deformation decreased. Of the four flip-chip devices studied, the underfilled flip-chip device mounted on the multi-layer substrate had the least deformed solder balls. 相似文献
2.
Paul S. Ho Guotao Wang Min Ding Jie-Hua Zhao Xiang Dai 《Microelectronics Reliability》2004,44(5):719-737
In this article, we review the reliability issues for plastic flip-chip packages, which have become an enabling technology for future packaging development. The evolution of area-array interconnects with high I/O counts and power dissipation has made thermal deformation an important reliability concern for flip-chip packages. Significant advances have been made in understanding the thermo-mechanical behavior of flip-chip packages based on recent studies using moiré interferometry. Results from moiré studies are reviewed by focusing on the role of the underfill to show how it reduces the shear strains of the solder balls but shifts the reliability concern to delamination of the underfill interfaces. The development of the high-resolution moiré interferometry based on the phase-shift technique provided a powerful method for quantitative analysis of thermal deformation and strain distribution for high-density flip-chip packages. This method has been applied to study plastic flip-chip packages and the results and impacts on delamination at the die/underfill interface and in the underfill region above the plated through-hole via are discussed. Here a related reliability problem of die cracking during packaging assembly and test is also discussed. Finally, we discuss briefly two emerging reliability issues for advanced flip-chip packages, one on the packaging effect on Cu/low k interconnect reliability and the other on electromigration of solder balls in flip-chip packages. 相似文献
3.
A new accelerated stress test method was developed to evaluate creep life of flip-chip solder joints with underfill. With this method, a cyclic creep test can be done simply by applying a displacement to the FR-4 printed circuit board (PCB) board in the axial direction. The creep fatigue test was performed under displacement control with real-time electrical continuity monitoring. Test results show that the displacement arising from the force is equivalent to the thermal stress during thermal expansion. It was found that the magnitude of displacement was proportional to the inelastic strain sustained by the solder joints. This indicates that the creep fatigue life obtained will not only reflect the quality of the solder joints, but can also be used to characterize the reliability of the flip-chip assembly. Finite element modeling was also performed to confirm the agreement of deformation of the solder joints under mechanical and thermal loading. Results suggest that deformation and strain of the flip-chip assembly are consistent or comparable between the mechanical and thermal cycling. The failure analysis indicates that fatigue cracks often initiate from the top edge of a corner solder joint in the creep fatigue test, which is similar to what would happen in thermal cycling test. Lastly, the effect of underfill on the creep fatigue test is discussed. It is postulated that the test method is applicable to other flip-chip assemblies, such as conductive adhesive interconnections. 相似文献
4.
基于埋置式基板的3D-MCM封装结构的研制 总被引:2,自引:0,他引:2
研制一种用于无线传感网的多芯片组件(3D-MCM) . 采用层压、开槽等工艺获得埋置式高密度多层有机(FR-4)基板,通过板上芯片(COB) 、板上倒装芯片(FCOB) 、球栅阵列(BGA)等技术,并通过引线键合、倒装焊等多种互连方式将不同类型的半导体芯片三维封装于一种由叠层模块所形成的立体封装结构中;通过封装表层的植球工艺形成与表面组装技术(SMT)兼容的BGA器件输出端子;利用不同熔点焊球实现了工艺兼容的封装体内各级BGA的垂直互连,形成了融合多种互连方式3D-MCM封装结构. 埋置式基板的应用解决了BGA与引线键合芯片同面组装情况下芯片封装面高出焊球高度的关键问题. 对封装结构的散热特性进行了数值模拟和测试,结果表明组件具有高的热机械可靠性. 电学测试结果表明组件实现了电功能,从而满足了无线传感网小型化、高可靠性和低成本的设计要求. 相似文献
5.
《Microelectronics Reliability》2014,54(6-7):1206-1211
With the aim to miniaturize and to reduce the cost, the increasing demand, regarding to advanced 3D-packages as well as high performance applications, accelerates the development of 3D-silicon integrated circuits. The trend to smaller and lighter electronics has highlighted many efforts towards size reduction and increased performance in electronic products. The radio frequency (RF) performances are limited by parasitic effects due to the resistor–inductor–capacitor (RLC) network, between the wire bond connections from the dies to the lead frame. The use of flip-chip bonding technology for very fine pitch packaging allows high integration and limits parasitic inductances. Electromigration (EM) and thermomigration (TM) may have serious reliability issues for fine-pitch Pb-free solder bumps in the flip-chip technology used in consumer electronic products. A possibility to extend the reliability is the use of plastic ball in the solder bumps. Bumps containing a plastic solder balls have an excellent reliability. Using a plastic ball with a low Young modulus, the solder hardness is moderated and the stress on a ball is relaxed. Due to this, the stress does not concentrate on the solder joint which prolongs the lifetime. In this investigation, the thermal–electrical–mechanical coupling of electromigration on bumps containing a plastic solder is studied. 相似文献
6.
Underfill constraint effects during thermomechanical cycling of flip-chip solder joints 总被引:2,自引:0,他引:2
The presence of an “underfill” encapsulant between a microelectronic device and the underlying substrate is known to substantially
improve the thermal fatigue life of flip-chip (FC) solder joints, primarily due to load-transfer from the solder to the encapsulant.
In this study, a new single joint-shear (SJS) test, which allows the measurement of the strain response of an individual solder
ball during thermomechanical cycling (TMC), has been used to investigate the impact of the constraint imposed by the underfill
on a solder joint. Finite element (FE) modeling has been used to demonstrate that the SJS sample geometry captures most of
the deformation characteristics of an FC joint and to provide insight into experimental observations. It has been shown that
the strain response of a eutectic Pb-Sn solder joint is influenced significantly by in-situ microstructural coarsening during
TMC, which in turn is dependent on the underfill properties. In general, underfill properties, which allow the imposition
of large compressive-hydrostatic stresses on the solder joint, were the most effective in reducing coarsening. Phase coarsening
prevented the stabilization of the stress-strain response of the solder, even in the absence of crack damage, and was found
to depend strongly on the local inelastic-strain state within the joint. This necessitates that future solder deformation
models account for strain-history-dependent microstructural evolution and that underfill properties be optimized to minimize
the extent of coarsening during TMC in order to maximize joint life. 相似文献
7.
Finite element based fatigue life estimation of the solder joints with effect of intermetallic compound growth 总被引:1,自引:0,他引:1
This paper develops an analysis procedure to study the effects of intermetallic compound (IMC) growth on the fatigue life of 63Sn-37Pb (lead-rich)/96.5Sn-3.5Ag (lead-free) solder balls for flip-chip plastic ball grid array packages under thermal cycling test conditions. In this analysis procedure, the thickness of the IMC increased with the number of thermal cycles, and was determined using the growth rate equation. A series of non-linear finite element analyses was conducted to simulate the stress/strain history at the critical locations of the solder balls with various IMC thicknesses in thermal cycling tests. The simulated stress/strain results were then employed in a fatigue life prediction model to determine the relationship between the predicted fatigue life of the solder ball and the IMC thickness. Based on the concept of continuous damage accumulation and incorporated with the linear damage rule, this study defines the damage of each thermal cycle as the reciprocal of the predicted fatigue life of the solder joints with the corresponding IMC thickness. The final fatigue failure of the solder ball was determined as the number of cycles corresponding to the cumulative damage equal to unity. Results show that the solder joint fatigue life decreased as the IMC thickness increased. Moreover, the predicted thermal fatigue life of lead-rich solders based on the effects of IMC growth is apparently smaller than that without considering the IMC growth in the reliability analysis. Results also show that the influence of the IMC thickness on the fatigue life prediction of the lead-free solder joint can be ignored. 相似文献
8.
9.
Zhang Z.Q. Shi S.H. Wong C.P. 《Components and Packaging Technologies, IEEE Transactions on》2001,24(1):59-66
No-flow underfill process in flip-chip assembly has become a promising technology toward a smaller, faster and more cost-efficient packaging technology. The current available no-flow underfill materials are mainly designed for eutectic tin-lead solders. With the advance of lead-free interconnection due to the environmental concerns, a new no-flow underfill chemistry needs to be developed for lead-free solder bumped flip-chip applications. Many epoxy resin/hexahydro-4-methyl phthalic anhydride/metal acetylacetonate material systems have been screened in terms of their curing behavior. Some potential base formulations with curing peak temperatures higher than 200°C (based on differential scanning calorimetry at a heating rate of 5°C/min) are selected for further study. The proper fluxing agents are developed and the effects of fluxing agents on the curing behavior and cured material properties of the potential base formulations are studied using differential scanning calorimetry, thermomechanical analysis, dynamic-mechanical analysis, thermogravimetric analysis, and rheometer. Fluxing capability of the developed no-flow formulations is evaluated using the wetting test of lead-free solder balls on a copper board. The developed no-flow underfill formulations show sufficient fluxing capability and good potential for lead-free solder bumped flip-chip applications 相似文献
10.
Galloway J. Syed A. WonJoon Kang JinYoung Kim Cannis J. Ka Y. SeungMo Kim TaeSeong Kim GiSong Lee SangHyun Ryu 《Components and Packaging Technologies, IEEE Transactions on》2005,28(2):297-302
Ball grid array (BGA) package styles use solder balls as electrical interconnects between packages and application boards. Solder balls are rigid and tend to fracture under thermal fatigue and/or shock loading. Metalized polymer spheres (MPS) offer a more compliant interconnect, compared to solder balls, thereby increasing the thermal cycling fatigue life. A reduction in thermal and electrical performance may be expected for MPS interconnects as a result of its higher thermal and electrical resistances. A 5% and an 8% increase in MPS thermal resistance was measured for a carrier array ball grid array (CABGA) package and a plastic ball grid array (PBGA) package, respectively, compared to eutectic solder balls. However, this small reduction was offset by large gains in the solder joint life. A 1.6 times increase in the mean thermal fatigue life was measured for a CABGA using MPS interconnects compared to eutectic solder balls. A first-order model showed that eutectic solder balls provide greater process margins, compared to MPS interconnects, due to the ball collapse during reflow. 相似文献
11.
Yeh-Fang Duann Jen-Hung Chiang Shung-Jim Yang Hsun-Wen Chang 《Journal of Electronic Materials》2005,34(7):1026-1029
The 63Sn-37Pb solder ball (φ=300 μm) was attached to gold-nickel-plated plastic ball grid array (PBGA) substrates, with gold
and nickel thicknesses of 0.6 μm and 7 μm, respectively. The thickness of the intermetallic compound (IMC) in solder balls
was measured following each instance of infrared (IR) reflow (90 sec at 230 °C), level II preconditioning, a pressure cooking
test (for 96 h or 168 h), and a temperature cycle test (with 500 or 1,000 cycles). Scanning electron microscopy (SEM) was
used to identify the cross-section sites of the solder balls following testing. Following all the reliability tests, the IMC
demonstrated that an IMC thickness exceeding 5 μm will reduce the solder ball shear strength owing to diffusion of Ni into
the solder balls. 相似文献
12.
《Advanced Packaging, IEEE Transactions on》2009,32(4):711-719
13.
This paper reports a novel method to enhance solder ball or solder ring bonding strength by using electrowetting-on-dielectric (EWOD) effect. With a low melting point, the metal Sn has been widely used in electronic packaging technology. Since Sn will be molten into liquid when the temperature is increased above the melting point, the method for treating liquid can be herein employed. Contact angle of the molten Pb-free balls or ring structure on silicon substrate have been experimentally changed by applying electric field across the thin dielectric film between the molten solder and the conductive silicon substrate. The contact area between the solder and the substrate is enlarged due to the decrease of the contact angle. Our testing results on the EWOD enhanced packaging structures of solder balls, flip-chip and solder ring hermetic package generally show about 50% enhancement in bonding shear strength. The significantly enhanced solder link bonding strength is hopeful for improving packaging reliability and is promising to be used in high performance silicon based electronic or microelectromechanic SiP (system in package) technologies. 相似文献
14.
Yoshiharu Kariya Takuya Hosoi Shinichi Terashima Masamoto Tanaka Masahisa Otsuka 《Journal of Electronic Materials》2004,33(4):321-328
The mechanical shear fatigue test has been performed to study the effect of silver content on the fatigue properties of Sn-xAg-0.5Cu
(x=1, 2, 3, and 4) for flip-chip interconnections. The strength of the solder alloy increases with increasing silver content,
preventing shear plastic deformation of the solder bump. The flip-chip joints made using higher silver content solder, such
as 3%Ag and 4%Ag, exhibit longer fatigue life for all conditions. The fatigue ductility of the solder decreases with an increase
in the silver content. The fatigue endurance of 1%Ag solder is superior to other solders over the plastic strain range of
3%, even though the strength of the solder is the lowest in the solders tested. Based on this study, the 3Ag solder may exhibit
good fatigue performance for all conditions, and the 1Ag solder is optimum for severe strain conditions. 相似文献
15.
16.
Effect of Size of Lid-Substrate Adhesive on Reliability of Solder Balls in Thermally Enhanced Flip Chip PBGA Packages 总被引:1,自引:0,他引:1
Jen Y.-M. Fang C.-K. Yeh Y.-H. 《Components and Packaging Technologies, IEEE Transactions on》2006,29(4):718-726
Six design cases of lid-substrate adhesive with various combinations of widths and heights were analyzed to investigate how the size of the adhesive affects the reliability of the solder balls of thermally enhanced flip chip plastic ball grid array (FC-PBGA) packages in thermal cycling tests. Analysis results were compared with data on the reliability of conventional FC-PBGA packages. Thermal-mechanical behavior was simulated by the finite element (FE) method and the eutectic solder was assumed to exhibit elastic-viscoplastic behavior. The temperature-dependent nonlinear stress/strain relationship of the adhesive was experimentally determined and used in the FE analysis. Darveaux's model was employed to obtain the predicted fatigue life of the solder ball. Simulation results reveal that the fatigue life of the solder balls in thermally enhanced FC-PBGA packages is much shorter than that in conventional FC-PBGA packages, and the life of solder balls increases with both the width and the height of the adhesive. However, the effect of the width of the adhesive on the reliability of the solder ball is stronger than that of the height. Moreover, increasing either the width or the height reduces the plastic strain in the adhesive at critical locations, indicating that the reliability of the adhesive can be improved by its size. The predicted results of the life of solder balls for some selected studied packages are also compared with experimental data from thermal cycling tests in the paper 相似文献
17.
Grain-boundary character and grain growth in bulk tin and bulk lead-free solder alloys 总被引:1,自引:0,他引:1
A. U. Telang T. R. Bieler J. P. Lucas K. N. Subramanian L. P. Lehman Y. Xing E. J. Cotts 《Journal of Electronic Materials》2004,33(12):1412-1423
Grain-boundary deformation is the primary failure mode observed in solder joints. Understanding the effects of alloy composition
variations and cooling rates on microstructural stability and deformation processes will allow development of improved joints.
The effects of these variables on grain-boundary character were investigated in a pure-tin ingot and a reflowed sample; ingots
of Sn-3.5wt.%Ag and Sn-3.8wt.%Ag-0.7wt.%Cu; and solder balls with 1.63-wt.% or 3-wt.%Ag. The microstructure was characterized
using orientation imaging microscopy (OIM). After aging (150°C for 200 h), the fine-grained polycrystalline microstructure
in both pure-tin specimens grew considerably, revealing preferred misorientations and ledge formation at grain boundaries.
Aging of the alloy ingots showed only slight grain growth caused by precipitate pinning. The solder balls showed similar phenomena.
The role of alloying elements, cooling rate, and the anisotropy of the coefficient of thermal expansion (CTE) in tin on microstructural
evolution, grain-boundary character, and properties of solder joints are discussed. 相似文献
18.
The ball impact test was developed as a package-level measure for the board-level drop reliability of solder joints in the
sense that it leads to fracturing of solder joints around intermetallics, similar to that from a board-level drop test. We
investigated numerically the effects of constitutive relationships of solder alloy on transient structural responses of a
single package-level solder joint subjected to ball impact testing. This study focused on the characteristics of the ascending
part of the impact force profile. According to the piecewise linear stress-strain curve obtained for the Sn-4Ag-0.5Cu solder
alloy, parametric studies were performed by varying either segmental moduli or characteristic stresses of the curve at fixed
ratios, with regard to the lack of available rate-dependent material properties of solder alloys. 相似文献
19.
高密度陶瓷封装倒装焊器件的焊点尺寸已降低至100μm以下,焊点电流密度达到10~4 A/cm~2以上,由此引发的电迁移失效成为不可忽视的问题。以陶瓷封装菊花链倒装焊器件为研究对象,开展了Sn10Pb90、Sn63Pb37焊点热电环境可靠性评估试验,通过电连接检测及扫描电子显微镜(SEM)等方法对焊点互连情况进行分析。结果表明,Sn63Pb37焊点阴极侧金属间化合物(IMC)增长明显,表现出明显的极化现象,IMC厚度的平方与通电时间呈线性关系。通电时间达到576 h后Sn63Pb37焊点阴极侧产生微裂纹,而Sn10Pb90焊点在通电576 h后仍未出现异常,表现出优异的电迁移可靠性。研究结果对于直径100μm微焊点的陶瓷封装倒装焊器件的应用具有重要的意义。 相似文献
20.
Kozo Shimizu Teru Nakanishi Kazuaki Karasawa Kaoru Hashimoto Koichi Niwa 《Journal of Electronic Materials》1995,24(1):39-45
Recent high-density very large scale integrated (VLSI) interconnections in multichip modules require high-reliability solder
interconnection to enable us to achieve small interconnect size andlarge number of input/output terminals, and to minimize
soft errors in VLSIs induced by α-particle emission from solder. Lead-free solders such as indium (In)-alloy solders are a
possible alternative to conventional lead-tin (Pb-Sn) solders. To realize reliable interconnections using In-alloy solders,
fatigue behavior, finite element method (FEM) simulations, and dissolution and reaction between solder and metallization were
studied with flip-chip interconnection models. We measured the fatigue life of solder joints and the mechanical properties
of solders, and compared the results with a computer simulation based on the FEM. Indium-alloy solders have better mechanical
properties for solder joints, and their flip-chip interconnection models showed a longer fatigue life than that of Pb-Sn solder
in thermal shock tests between liquid nitrogen and room temperatures. The fatigue characteristics obtained by experiment agree
with that given by FEM analysis. Dissolution tests show that Pt film is resistant to dissolution into In solder, indicating
that Pt is an adequate barrier layer material for In solder. This test also shows that Au dissolution into the In-Sn solder
raises its melting point; however, Ag addition to In-Sn solder prevents melting point rise. Experimental results show that
In-alloy solders are suitable for fabricating reliable interconnections. 相似文献