Enhancement of creep resistance and thermal behavior of eutectic Sn–Cu lead-free solder alloy by Ag and In-additions

El-Daly, A.A.; Hammad, A.E.

doi:10.1016/j.matdes.2012.04.007

Cited by 124 publications

(53 citation statements)

References 17 publications

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“…Furthermore, the ternary Sn-Bi-Cu ternary alloys may also be considered as promising lead-free solders 19 . Recently, Ag, Bi or In-containing Sn-Cu alloys have received some attention, and in several prominent reliability test programs Sn-Cu-Ag and Sn-Cu-In alloys demonstrated superior performance, at least in its mechanical strength 20,21 . Tai et al 22 showed that creep resistance of Sn-3.5Ag was improved significantly for Cu particle-reinforced composite solder joints at 25 o C, 65 o C and 105 o C. The tensile strength increased with increasing Bi content in the Sn-Cu eutectic solder alloy, which was attributed to the presence of Bi and its role in refining microstructure and solid solution strengthening 23 .…”

Section: Introductionmentioning

confidence: 99%

Microstructural evolution and mechanical properties of Sn-Bi-Cu ternary eutectic alloy produced by directional solidification

2018

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Sn-36Bi-22Cu (wt.%) ternary eutectic alloy was prepared using vacuum melting furnace and casting furnace. The samples were directionally solidified upwards solidification rate varying from 8.3 to 166 µm/s and at a constant temperature gradient (4.2 K/mm) in a Bridgman-type directional solidification furnace. The composition analysis of the phases and the intermetallics (Cu 3 Sn and Cu 6 Sn 5 ) were determined from EDX and XRD analysis respectively. The variation of the lamellar spacing (Bi-rich phase) and the Cu 3 Sn phase spacing with the solidification rate were investigated. The dependence of microhardness, ultimate compressive strength and compressive yield strength on solidification rate were determined. The spacing and microhardness were measured from both longitudinal and transverse sections of the samples. The dependence of microhardness on the lamellar spacing and the Cu 3 Sn phase spacing were also determined. The relationships between phase spacings, solidification rate and mechanical properties were determined from linear regression analysis.

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Section: Introductionmentioning

confidence: 99%

Microstructural evolution and mechanical properties of Sn-Bi-Cu ternary eutectic alloy produced by directional solidification

2018

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“…In the studies of El-Daly and Hammad [113,120] Increasing amount of SiC reinforcement also resulted in an increase of the microhardness value of the reinforced solder. The findings of Wang et al [114], on studying the influence of SiC reinforcements to Sn-3.7Ag-0.9Zn where β-Sn dendrites, Ag3Sn and AgZn intermetallics were able to be refined, can be observed in Figure 21.…”

Section: Mechanical Properties Of Reinforced Soldermentioning

confidence: 96%

“…Effects of Ag and In additions is reported to result in formations of fine primary Ag3Sn fibers and Cu6Sn5 eutectic microstructure [113]. As shown in Figure 13, the additions of Ag and In result in a refining of β-Sn grains and may improve the creep resistance properties of the solder.…”

Section: Microstructure Of Reinforced Soldermentioning

confidence: 97%

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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“…Therefore, several Pb-free solder alloys, including Sn-Zn [4] , Sn-Sb [5] , Sn-Cu [6] and Sn-Ag alloys [7] , have received more attention. In fact, full implementation of new Pb-free solders implies a detailed knowledge and understanding of their thermodynamics, wettability, microstructure, and so on.…”

Section: Introductionmentioning

confidence: 99%

“…In fact, full implementation of new Pb-free solders implies a detailed knowledge and understanding of their thermodynamics, wettability, microstructure, and so on. Ji [8] studied Sn-0.7Cu solder alloy by pressureless and fluxless ultrasonic-assisted die bonding, they observed that the joint consisted of sole (Cu,Ni) 6 Sn 5 plus a thin layer of Cu 3 Sn, and compared with transient-liquid-phase soldering, this method dramatically reduces the processing time and there was no external force acted on the dies. Spinelli [9] investigated the interrelationship of thermal parameter, microstructure and microhardness of Bi-Ag solder alloys by directional solidification.…”

Section: Introductionmentioning

confidence: 99%

Effect of reflow cycles on interfacial morphology of Sn-3.0Ag-0.5Cu/Cu soldered joints during solid-state aging

Cao

Cui

et al. 2018

Proceedings of the 2018 8th International Conference on Manufacturing Science and Engineering (ICMSE 2018)

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Abstract. The morphology of intermetallic compounds (IMCs) at Sn-3.0Ag-0.5Cu/Cu interface was investigated during solid-state aging with multiple reflow cycles. Results showed the scallop shape of Cu 6 Sn 5 becomes elongated type with an increase in the aspect ratio gradually with increasing reflow cycles. Moreover, the thicknesses of the interfacial IMCs layer all increase linearly with the square root of aging time whatever reflow soldering cycles, and the growth kinetics equations of different reflow cycles are obtained by linear regression. It confirms that the growth of all IMCs layers follows the diffusion control mechanism. It is worth to mention that the growth coefficients increase successively with the addition of reflow cycle, indicating the IMCs layer would be thicker as increasing reflow cycles. Hence, to improve the reliability of solder joint, only one reflow cycle and proper soldering time is needed.

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Enhancement of creep resistance and thermal behavior of eutectic Sn–Cu lead-free solder alloy by Ag and In-additions

Cited by 124 publications

References 17 publications

Microstructural evolution and mechanical properties of Sn-Bi-Cu ternary eutectic alloy produced by directional solidification

Microstructural evolution and mechanical properties of Sn-Bi-Cu ternary eutectic alloy produced by directional solidification

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

Effect of reflow cycles on interfacial morphology of Sn-3.0Ag-0.5Cu/Cu soldered joints during solid-state aging

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