The effects of additives to SnAgCu alloys on microstructure and drop impact reliability of solder joints

Liu, Weiping; Lee, Ning-Cheng

doi:10.1007/s11837-007-0085-5

Cited by 89 publications

(45 citation statements)

References 4 publications

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“…In solder joints specifically, the microstructure can affect the performance including the fatigue life during thermal cycling [135], the tolerance to drop impacts [136] and the resistance to electromigration [137]. Since the mechanism by which reinforcement particle additions cause a refinement in the the intermetallics present in are unclear, this study focuses on the microstructure formation in reinforced solder joints.…”

Section: Summary and Remarksmentioning

confidence: 99%

Microstructure Formation in Reinforced Sn-Cu Lead-free Solder Alloys

Salleh¹,

Anuar²

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Electronics manufacturers are pushing the limits in reducing the physical size of circuitry while simultaneously increasing the number of transistors to satisfy Moore's Law [1]. This includes investing in new materials, and configuring new ways to manufacture complex 3D (three dimensional) electronic packaging [1]. One key requirement of new materials and techniques is ensuring the high reliability of the resultant products in various challenging operating environments including thermal and mechanical extremes [2][3][4]. A viable method to enhance the properties and performance of a solder joint is by incorporation of reinforcement particles to the solder matrix, either by intrinsic or extrinsic methods. In this thesis a series of Sn-Cu Pb-free solder alloys with extrinsic or intrinsic phase reinforcement were manufactured and the microstructure and soldering behavior were investigated in detail.Additions of extrinsic reinforcement in the form of nano-sized ceramic material were made using a microwave sintering powder metallurgy (PM) method, which is a viable method to improve the mechanical and thermal properties of Pb-free solder materials. In addition, the advanced processing routes ensures a homogenous distributions of reinforcement particles is present. To investigate the performance of the reinforced bulk solders including thermal and mechanical properties and relate this to the microstructure, samples were investigated using techniques such as synchrotron micro-XRF, HRTEM, SEM, XPS, dilatometery, DSC and shear and microhardness testing. A hypothesis of how reinforcement improves solder properties is developed and discussed. Synchrotron X-ray radiography imaging (SXRI) was used to analyse the development of microstructure and the complex interactions occurring in the solders. Based on the properties of the fabricated solder, the microwave sintering PM route was discussed as a promising method for the reinforcement of Pb-free solders.The initial formation of interfacial IMC products was studied in Sn-Cu based solder alloys by in situ experiment techniques such as SXRI and UHV-TEM. The results provide direct experimental evidence of real-time initial Cu6Sn5 layer development during soldering and also the stress creation and release events that arise due to the polymorphic transformations of the Cu6Sn5 phase and the associated volumetric change.ii In addition, the nucleation and growth behavior of primary intermetallics which can be considered an intrinsic reinforcing material in solder joints was studied. Here, the nucleation and growth behavior of primary Cu6Sn5 and β-Sn crystals in some of the most commonly used solder alloys including Sn-0.7Cu and Sn-3.0Ag-0.5Cu is explained. This also includes the effects of Ni additions for refining primary Cu6Sn5 in Sn-Cu solder joints. Using SXRI, observations were made during solder joint solidification, which is difficult using conventional methods. The initial nucleation and solidification kinetics of primary Cu6Sn5 crystals were discussed.The growth of pri...

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Section: Summary and Remarksmentioning

confidence: 99%

Microstructure Formation in Reinforced Sn-Cu Lead-free Solder Alloys

Salleh¹,

Anuar²

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“…A variety of lead-free solder alloys have been investigated, such as SnAg, SnCu, SnAgCu and so on. These alloys have good solderability, thermal fatigue reliability and compatibility with the components and circuits [5]. Hence, they are recommended to be the most potential alternatives for SnPb solder [6][7][8][9][10][11].…”

Section: Introductionmentioning

confidence: 99%

“…Liu et al [5,12] reported that the Mn/Ce doped Sn1.0Ag0.5Cu alloys achieved a homogeneous microstructure, high strength in drop tests and high reliability in dynamic bending tests. The Sn1.0Ag0.5Cu ?…”

Section: Introductionmentioning

confidence: 99%

The effects of Mn powder additions on the microstructures and tensile property of SnAgCu/Cu solder joints

Shen

Zhang

et al. 2014

J Mater Sci: Mater Electron

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In this paper, the effects of Mn powder on fusion property of Sn3.0Ag0.5Cu solder alloy and microstructures as well as tensile property of the solder joints of Sn3.0Ag0.5Cu/Cu were investigated by differential scanning calorimetry analysis, scanning electron microscopy and tensile tests. The results showed that the addition of Mn dramatically suppressed under cooling of SnAgCu solder alloy. Mn addition contributed to the growth of Cu 6 Sn 5 intermetallic compound layers since it provided nucleation sites for Cu 6 Sn 5 at the solder joints. Moreover, Mn addition increased the hardness of the solder alloys and reduced the tensile strength of SnAgCu/Cu solder joints. During aging, the growth of IMC layers of SnAgCuMn/Cu solder joints was slower than that of SnAgCu/Cu solder joints, and the tensile strength of all the solder joints increased after aging.

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“…The effects of reinforcement on the microstructural, mechanical, thermal and electrical properties of the resultant composite solder have been extensively investigated by several researchers [9][10][11][12]. One of the choices of reinforcement is carbon nanotubes (CNTs).…”

Section: Introductionmentioning

confidence: 99%

Creep mitigation in Sn–Ag–Cu composite solder with Ni-coated carbon nanotubes

Han

Jing

Nai

et al. 2011

J Mater Sci: Mater Electron

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In the present study, the powder metallurgy route was used to successfully incorporate Ni-coated carbon nanotubes into SnAgCu solder, to form a nanocomposite solder. Nanoindentation tests were performed on both composite and SnAgCu solder samples to investigate their creep behaviour at room temperature. Characterization results revealed that with the addition of Ni-coated carbon nanotubes, the creep behaviour of composite solder improved significantly as compared to that of the unreinforced solder alloy. Moreover, increasing the maximum load from 20 to 100 mN increased the percentage reduction in creep strain rate from 4 to 28%, for the composite compared to SnAgCu solder after 300 s of holding.

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The effects of additives to SnAgCu alloys on microstructure and drop impact reliability of solder joints

Cited by 89 publications

References 4 publications

Microstructure Formation in Reinforced Sn-Cu Lead-free Solder Alloys

Microstructure Formation in Reinforced Sn-Cu Lead-free Solder Alloys

The effects of Mn powder additions on the microstructures and tensile property of SnAgCu/Cu solder joints

Creep mitigation in Sn–Ag–Cu composite solder with Ni-coated carbon nanotubes

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