Solder Volume Effect on Electromigration Failure Mechanism of Cu/Ni/Sn-Ag Microbumps

Park, Young-Bae; Park, Gyutae; Lee, Byeong-Rok; Kim, Jun-Beom; Son, Kirak

doi:10.1109/tcpmt.2020.3005644

Cited by 8 publications

(4 citation statements)

References 39 publications

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“…10 The images of Sn-3.5Ag/Al interfaces at 265 °C: for a 30 s of cross section and b vertical section, c 60 min of cross section and d vertical section [50] thereby reducing Kirkendall voids formed. Sn-3.5Ag/Cu can dissolve more Cu at higher reflux temperature [6]. It was found that adding 0.5 wt.% Cu in solder could reduce the dissolution rate of Cu.…”

Section: Sn-agmentioning

confidence: 94%

See 1 more Smart Citation

Microstructure and properties of Sn-Ag and Sn-Sb lead-free solders in electronics packaging: a review

Wang

Zhang

2021

J Mater Sci: Mater Electron

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Electronic devices need to work at high temperature in some fields for a long time, peculiarly step soldering technology, primary packaging and flip-chip connections, etc., along with the application of electronic products more and more widely. These phenomena promote the further development of hightemperature solders. Because of the high melting temperatures of Sn-Ag and Sn-Sb, they are suitable for high-temperature fields such as automotive electronics and avionics. In this review, the influences of trace elements and nanoparticles on microstructure, intermetallic components (IMC) growth, mechanical properties, wettability, melting behavior, and creep behavior of Sn-Ag and Sn-Sb solders have been summarized systematically. It was found that the addition of trace elements or nanoparticles into solders to be beneficial in improving the performance of Sn-Ag and Sn-Sb solders. Besides, the melting behavior of the solder at high temperatures can be further improved if Sn-Ag and Sn-Sb are used better as high-temperature solders.

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Section: Sn-agmentioning

confidence: 94%

“…Sn-Pb solders progressively took the place of lead-free solders in electronic packaging [5]. At present, the lead-free solders that have been widely used for electronic packaging are mainly Sn-Ag [6,7], Sn-Ag-Cu [8,9], Sn-Zn [10], Sn-Cu [11], Sn-Bi [12,13], etc., in recent years.…”

Section: Introductionmentioning

confidence: 99%

Microstructure and properties of Sn-Ag and Sn-Sb lead-free solders in electronics packaging: a review

Wang

Zhang

2021

J Mater Sci: Mater Electron

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“…Park et al investigated the electromigration performance of Cu pillar/Ni/Sn-Ag to analyze the potential mechanisms by which Ni layers improve the resistance to electromigration. Xu and Fu et al investigated the effect of grain orientation on electromigration properties and found that grain orientation rotated in response to electron flow [ 10 , 11 , 12 ]. In previous work [ 13 , 14 , 15 ], experimental and theoretical studies on Cu pillar microbumps were carried out and determined structural evolution, failure mechanisms, and life prediction models of lead-free solder under the micro-size effect.…”

Section: Introductionmentioning

confidence: 99%

Interfacial Reaction and Electromigration Failure of Cu Pillar/Ni/Sn-Ag/Cu Microbumps under Bidirectional Current Stressing

Chen

Zhao

et al. 2023

Materials

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The electromigration behavior of microbumps is inevitably altered under bidirectional currents. Herein, based on a designed test system, the effect of current direction and time proportion of forward current is investigated on Cu Pillar/Ni/Sn-1.8 Ag/Cu microbumps. Under thermo-electric stressing, microbumps are found to be susceptible to complete alloying to Cu6Sn5 and Cu3Sn. As a Ni layer prevents the contact of the Cu pillar with the solder, Sn atoms mainly react with the Cu pad, and the growth of Cu3Sn is concentrated on the Cu pad sides. With direct current densities of 3.5 × 104 A/cm2 at 125 °C, the dissolution of a Ni layer on the cathode leads to a direct contact reaction between the Cu pillar and the solder, and the consumption of the Cu pillar and the Cu pad shows an obvious polarity difference. However, with a bidirectional current, there is a canceling effect of an atomic electromigration flux. With current densities of 2.5 × 104 A/cm2 at 125 °C, as the time proportion of the forward current approaches 50%, a polarity structural evolution will be hard to detect, and the influence of the chemical flux on Cu-Sn compounds will be more obvious. The mechanical properties of Cu/Sn3.0Ag0.5Cu/Cu are analyzed at 125 °C with direct and bidirectional currents of 1.0 × 104 A/cm2. Compared with high-temperature stressing, the coupled direct currents significantly reduced the mechanical strength of the interconnects, and the Cu-Sn compound layers on the cathode became the vulnerable spot. While under bidirectional currents, as the canceling effect of the electromigration flux intensifies, the interconnect shear strength gradually increases, and the fracture location is no longer concentrated on the cathode sides.

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“…[ 1,2 ] Microbump interconnects have become the critical technology for improving the integration of microelectronic devices. [ 3 ] However, minute‐sized solder joints have to withstand a heavier current density, and its mechanical properties, electrical properties are also different. [ 4 ] Further, rich Sn in lead‐free exacerbates the Cu‐Sn interface reaction that causes the excessive growth of IMCsand changes the evolution mechanism.…”

Section: Introductionmentioning

confidence: 99%

Influence of Temperature and Current Stressing on Cu‐Sn Intermetallic Compound Growth Characteristics of Lead‐Free Microbump

Wei

Guo

et al. 2023

Advcd Theory and Sims

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A numerical analysis of the Cu flux on Cu/Sn/Cu is successfully used to establish kinetic models that are verified with reported data. Kinetic models are adopted to discuss the polarity effect of intermetallic compounds (IMCs) growth at different alloying stages. The models reveal that, before Sn solder is depleted during thermal aging, the net thermodiffusion Cu flux in Cu6Sn5 is over three times larger than that in Cu3Sn. While coupling with current stressing, the IMCs thickness increases from parabola‐like curves to a linear‐like relationship. The degree of influence decreases in the order of Cu6Sn5 on anode, Cu6Sn5 on cathode, Cu3Sn on anode, and Cu3Sn on cathode. Electromigration Cu flux in Sn is the critical factor that accelerates the anode's Cu6Sn5 growth, and its influence on the growth rate over 1000 times that on the anode's Cu3Sn. After Sn solder is depleted, Cu6Sn5 gradually converts into Cu3Sn, and its thickness is linearly decreases with square root of annealing time. When coupling with a current density of 1.0 × 105 A cm−2, the thickness ratio of Cu3Sn/Cu6Sn5 reduces from 1:2 to 1:6. Remarkably, irrespective of whether current exists or not, the depletion of Cu6Sn5 always takes much longer than that of Sn solder.

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Solder Volume Effect on Electromigration Failure Mechanism of Cu/Ni/Sn-Ag Microbumps

Cited by 8 publications

References 39 publications

Microstructure and properties of Sn-Ag and Sn-Sb lead-free solders in electronics packaging: a review

Microstructure and properties of Sn-Ag and Sn-Sb lead-free solders in electronics packaging: a review

Interfacial Reaction and Electromigration Failure of Cu Pillar/Ni/Sn-Ag/Cu Microbumps under Bidirectional Current Stressing

Influence of Temperature and Current Stressing on Cu‐Sn Intermetallic Compound Growth Characteristics of Lead‐Free Microbump

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