Sn–Ag–Cu solder reaction with Au/Pd/Ni(P) and Au/Pd(P)/Ni(P) platings

Ho, Cheng–En; Lin, Yung-Chi; Wang, S. J.

doi:10.1016/j.tsf.2012.12.070

Cited by 24 publications

(5 citation statements)

References 21 publications

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“…Gold surface finishes are widely used on pads in electronic packaging (Huang et al, 2013;Ho et al, 2013;Bukat et al, 2010;Xu et al, 2009). The reason is that Au is oxidation-resistant and exhibits excellent wettability for most Sn-based solder alloys.…”

Section: Introductionmentioning

confidence: 99%

Effect of Au-Sn IMCs’ formation and morphologies on shear properties of laser reflowed micro-solder joints

Liu

Wang

et al. 2015

Soldering &Amp; Surface Mount Technology

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Purpose – The purpose of this paper is to investigate the effect of typical morphologies of Au-Sn IMCs (intermetallic compounds) at the interfaces of solder and pads on shear properties of laser reflowed micro-solder joints. Design/methodology/approach – Sn-2.0Ag-0.75Cu-3.0Bi (SnAgCuBi) solder balls (120 μm in diameter), pads with 0.1, 0.5, 0.9 or 4.0 μm thickness of Au surface finish, and different laser input energies were utilized to fabricate micro-solder joints with Au-Sn IMCs having different typical morphologies. The joints were performed by a shear test through a DAGE bond test system. Fracture surfaces of the joints were analyzed by scanning electron microscopy and energy-dispersive X-ray spectrometry to identify fracture modes and locations. Findings – Morphologies of Au-Sn IMCs would affect shear properties of the joints remarkably. When needle-like AuSn4 IMCs formed at the interfaces of solder and pads, almost entire surfaces presented the manner of ductile fracture. Moreover, shear forces of this kind of solder joints were higher than those of joints without Au-Sn IMCs or with a nearly continuous/continuous Au-Sn IMCs layer. The reason was that the shear performance of the solder joints with needle-like AuSn4 IMCs was enhanced by an interlocking effect between solder and needle-like AuSn4 IMCs. As a nearly continuous or continuous Au-Sn IMCs layer formed, the fracture surfaces presented more character of brittle than ductile fracture. However, if an Au layer still remained under Au-Sn IMCs, the shear performance of the joints would be enhanced. Originality/value – The results in this study can be used to optimize microstructures and shear properties of laser reflowed micro-solder joints.

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Section: Introductionmentioning

confidence: 99%

Effect of Au-Sn IMCs’ formation and morphologies on shear properties of laser reflowed micro-solder joints

Liu

Wang

et al. 2015

Soldering &Amp; Surface Mount Technology

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“…As the solid-state aging time increased, the needle-type morphology of Ni 3 Sn 4 changed to a chunk-type morphology, and the Ni 3 P layer thickened. The Ni-Sn-P layer was supposed to be present between the Ni 3 Sn 4 and Ni 3 P layer [ 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 ]. However, after solid-state aging, it was not distinguished without the spalling of Ni 3 Sn 4 IMCs.…”

Section: Resultsmentioning

confidence: 99%

“…Here, thin Ni 3 P layers were visible underneath the Ni 3 Sn 4 IMCs only after 500 h of aging and the Ni-Sn-P layer was not detected in any specimen. Literatures reported that first forming phase was (Pd,Ni)Sn 4 during the reactions between Sn-based solders and ENEPIG [ 16 , 17 , 18 , 19 , 20 ]. Therefore, the Ni 3 Sn 4 layer was formed and grew under the branch-like (Pd,Ni)Sn 4 IMCs.…”

Section: Resultsmentioning

confidence: 99%

“…Experiments to verify the usefulness and mechanical reliability of ENEPIG have been performed with various kinds of solders. Most of the studies were performed with Sn-3.0Ag-0.5Cu solder [ 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 ] and a small number of studies were performed with Sn-Ag [ 25 , 26 ] and Sn-Bi alloys [ 27 , 28 ]. Through these experiments, it was proven that the use of ENEPIG, instead of ENIG, reduced the consumption of the Ni-P layer and delayed the formation of the Ni 3 SN 4 /Ni-Sn-P microstructure, thereby preventing brittle fracture and improving the mechanical reliability.…”

Section: Introductionmentioning

confidence: 99%

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Diffusion Barrier Properties of the Intermetallic Compound Layers Formed in the Pt Nanoparticles Alloyed Sn-58Bi Solder Joints Reacted with ENIG and ENEPIG Surface Finishes

2022

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Pt-nanoparticle (NP)-alloyed Sn-58Bi solders were reacted with electroless nickel-immersion gold (ENIG) and electroless nickel-electroless palladium-immersion gold (ENEPIG) surface finishes. We investigated formation of intermetallic compounds (IMCs) and their diffusion barrier properties at reaction interfaces as functions of Pt NP content in the composite solders and duration of solid-state aging at 100 °C. At Sn-58Bi-xPt/ENIG interfaces, typical Ni3Sn4/Ni3P(P-rich layer) microstructure was formed. With the large consumption of the Ni-P layer, the Ni-P and Cu layers were intermixed and Cu atoms spread over the composite solder after 500 h of aging. By contrast, a (Pd,Ni)Sn4/thin Ni3Sn4 microstructure was observed at the Sn-58Bi-xPt/ENEPIG interfaces. The (Pd,Ni)Sn4 IMC effectively suppressed the consumption of the Ni-P layer and Ni3Sn4 growth, functioning as a good diffusion barrier. Therefore, the Sn-58Bi-xPt/ENEPIG joint survived 500 h of aging without microstructural degradation. Based on the experimental results and analysis of this study, Sn-58Bi-0.05Pt/ENEPIG is suggested as the optimum combination for future low-temperature soldering systems.

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“…The reaction between the molten solder and Ni layer resulted in the establishment of different types of IMCs, depend on the types of solders as well as surface finish being applied. For Sn-Ag-Cu solder and ENIG surface finish, during initial reflow, the topmost Au layer dissolved into the molten solder, leaving the Ni layer exposed to the molten SAC solder [16]. The Ni then acts as barrier and prevents Cu diffusion (from Cu substrate) into the interface, thus limiting the IMC thickness formed as thin IMC layer (below 4µm) is desirable to achieve good metallurgical bonding.…”

Section: Interfacial Reaction Of Solder Alloy and Surface Finishmentioning

confidence: 99%

A review on the effect of surface finish and cooling rate on solder joint reliability

Kahar¹,

Akhtar²,

Idris³

et al. 2016

WIT Transactions on the Built Environment

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With increasing environmental concern over the toxicity of lead (Pb) combined with strict regulations, the use of lead-based solders provides an inevitable driving force for the development of lead-free solder alloys. Many studies have been conducted for the evaluation of the solder joint reliability with respect to solder alloys and surface finishes. However, as the demand of electronic devices is increasing, there is a need to improve the mechanical properties of the solder joint in order to keep up with the current evolution of electronic devices' technology. In this study, the effect of surface finish and cooling rate on solder joint reliability using nickel-based surface finish was summarized. The study focused on nickel based surface finish (ENIG and ENEPIG) with different cooling media, slow (furnace), medium (air) and fast (water). It was found that the type of surface finish and the cooling rate can change the morphology of the solder intermetallic compound (IMC) and directly changes the solder joint mechanical properties. A faster cooling rate was reported to provide finer IMC grains which might be translated into better solder joint strength. The findings presented here may provide a better understanding for further study and facilitate improvements in terms of solder joint reliability.

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Sn–Ag–Cu solder reaction with Au/Pd/Ni(P) and Au/Pd(P)/Ni(P) platings

Cited by 24 publications

References 21 publications

Effect of Au-Sn IMCs’ formation and morphologies on shear properties of laser reflowed micro-solder joints

Effect of Au-Sn IMCs’ formation and morphologies on shear properties of laser reflowed micro-solder joints

Diffusion Barrier Properties of the Intermetallic Compound Layers Formed in the Pt Nanoparticles Alloyed Sn-58Bi Solder Joints Reacted with ENIG and ENEPIG Surface Finishes

A review on the effect of surface finish and cooling rate on solder joint reliability

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