Controlling the microstructure from the gold-tin reaction

Tsai, Jang-Zern; Chang, C. W.; Shieh, Y. C.; Hu, Yu; Kao, C. R.

doi:10.1007/s11664-005-0231-1

Cited by 98 publications

(45 citation statements)

References 17 publications

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“…However, the development of lead-free solders for high temperature applications has not yet advanced 2,3) . Many research groups paid the attention to the Au-Sn, Zn-Sn and Bi-Ag system alloys as a candidate of lead-free alloys, in the viewpoint of heat, electricity and melting point properties [4][5][6][7][8][9][10] . However, Au system alloys were restricted in the application of high temperature solders because of high cost of Au.…”

Section: Introductionmentioning

confidence: 99%

Tensile Properties of Bi Alloys and a Case Study for Alloy Design in Their Application to High Temperature Solders

Choi

et al. 2017

Mater. Trans.

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The s-orbital energy levels (Mk) of some alloying elements in a Bi cluster model were obtained on the basis of the molecular orbital calculation. In contrast, binary Bi-Cu/-Ag/-Zn system alloys with ΔMk of 0.013-0.343 were manufactured and tension-or hardness-tested, where ΔMk was the compositional average of Mk. The ultimate tensile strength and hardness were improved as alloying elements were added and increased in alloys. There was the relation between the ultimate tensile strength, fracture strain or hardness and ΔMk. Further, the compositions of Bi-2.0Ag-0.5Cu (ΔMk: 0.180), Bi-5.0Ag-0.5Cu (ΔMk: 0.379) and Bi-0.25Cu-0.25Sb (ΔMk: 0.044) were proposed as ternary alloys. It is found that the ultimate tensile strength, fracture strain and hardness values of ternary alloys could be also able to predict using their estimation lines obtained from binary Bi system alloys.

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Section: Introductionmentioning

confidence: 99%

Tensile Properties of Bi Alloys and a Case Study for Alloy Design in Their Application to High Temperature Solders

Choi

et al. 2017

Mater. Trans.

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“…This observation is consistent with the microstructure results of reflowing a Ni/Au/Sn structure at 290°C. 15,16 While the eutectic microstructure and evolution of the plated Au/Sn on Ni after reflow were already investigated in Refs. 15 and 16, our research focus was to bond large Si chips to commercial ceramic packages without using any flux.…”

Section: Resultsmentioning

confidence: 99%

Fluxless Bonding of Large Silicon Chips to Ceramic Packages Using Electroplated Eutectic Au/Sn/Au Structures

Wang

Kim

Lee

2009

Journal of Elec Materi

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A fluxless process of bonding large silicon chips to ceramic packages has been developed using a Au-Sn eutectic solder. The solder was initially electroplated in the form of a Au/Sn/Au multilayer structure on a ceramic package and reflowed at 430°C for 10 min to achieve a uniform eutectic 80Au-20Sn composition. A 9 mm 9 9 mm silicon chip deposited with Cr/Au dual layers was then bonded to the ceramic package at 320°C for 3 min. The reflow and bonding processes were performed in a 50-mTorr vacuum to suppress oxidation. Therefore, no flux was used. Even without any flux, high-quality joints were produced. Microstructure and composition of the joints were studied using scanning electron microscopy with energy-dispersive x-ray spectroscopy. Scanning acoustic microscopy was used to verify the joint quality over the entire bonding area. To employ the x-ray diffraction method, samples were made by reflowing the Au/Sn/Au structure plated on a package. This was followed by a bonding process, without a Si chip, so that x-rays could scan the solder surface. Joints exhibited a typical eutectic structure and consisted of (Au,Ni)Sn and (Au,Ni) 5 Sn phases. This novel fluxless bonding method can be applied to packaging of a variety of devices on ceramic packages. Its fluxless nature is particularly valuable for packaging devices that cannot be exposed to flux such as sensors, optical devices, medical devices, and laser diodes.

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“…Many studies of the AuSn20 solder are focusing on the soldering process, the microstructure evolution in the soldering joints [6,7], and the solder alloy's performance [8][9][10]. Considering the manufacturing of this alloy, some unsolved problems still remain, such as the microstructure evolution in the processing and the mechanical behavior of the bulk AuSn20 solder alloy.…”

Section: Introductionmentioning

confidence: 99%

Evolution of primary phases and high-temperature compressive behaviors of as-cast AuSn20 alloys prepared by different solidification pathways

et al. 2011

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The as-cast AuSn20 eutectic alloys prepared by four different solidification pathways have been investigated in terms of the microstructure and the high-temperature compressive behaviors. The primary phases appeared in the four alloys are very sensitive to the cooling rate, which decrease in the size and the volume fraction as the cooling rate increases. The morphologies of the primary ζ′-Au 5 Sn phase are in dendritic at low cooling rate and change to rosette-like at high cooling rate. When the cooling rate is about 3.5× 10 4 K/min, the primary ζ′-Au 5 Sn can be suppressed but small δ-AuSn particles appear instead as the primary phase. The compressive behaviors at 220°C exhibit a low yielding stress and a long stress platform for the alloy prepared by injection casting with a copper crucible, which indicates an advantageous processing route for the production of the AuSn20 strips or foils.

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Controlling the microstructure from the gold-tin reaction

Cited by 98 publications

References 17 publications

Tensile Properties of Bi Alloys and a Case Study for Alloy Design in Their Application to High Temperature Solders

Tensile Properties of Bi Alloys and a Case Study for Alloy Design in Their Application to High Temperature Solders

Fluxless Bonding of Large Silicon Chips to Ceramic Packages Using Electroplated Eutectic Au/Sn/Au Structures

Evolution of primary phases and high-temperature compressive behaviors of as-cast AuSn20 alloys prepared by different solidification pathways

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