The Sn-3.5Ag-1.0Cu-0.1Zn/Cu Intermetallic Interface under Thermal Aging (original) (raw)
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Universiti Teknologi MARA, Perlis, 2012
Due to environmental concerns, lead-free solders were introduced to replace the lead-based solders in microelectronics devices technology. Although there were many lead-free solder available, the SnAg -Cu was considered as the best choice. But the solder has its draw backs in terms of melting temperature and intermetallic formations. To improve the solder, a fourth element Zn was added into the solder and was synthesized via powder metallurgy route. This research studies the effect of 0.1wt% Zn addition on the mechanical properties and intermetallic formation on Cu substrate. For the mechanical test, the Vickers hardness (Hν), yield strength (σ y) and ultimate tensile strength (σ UTS) were reported. The mechanical test for Zn based composites solder shows better properties compared to un-doped counterparts. For intermetallic, the solders were melted at 250 o C and aged at 150 o C until 400 hours. The phases formed and its growth was studied under SEM and by energy dispersive x-ray (EDX). The addition of Zinc has improved the mechanical properties of SnAg -Cu solder, while the SEM results show the presence of Cu 6 Sn 5 and Cu 3 Sn intermetallics. The addition of 0.1wt% Zn has retarded the growth of the Cu3Sn intermetallic but not the total intermetallic thickness.
Intermetallic Evolution of Sn-3.5 Ag-1.0 Cu-0.1 Zn/Cu Interface under Thermal Aging
2013
Due to environmental concerns, lead-free solders were introduced in replacing the leadbased solders in microelectronics devices technology. Although there are many lead-free solder available, the SnAg -Cu is considered the best choice. But the solder has its draw backs in terms of melting temperature and intermetallic formations. To improve the solder, a fourth element Zn was added into the solder. The new composite solders were synthesized via powder metallurgy route. This research studies the effect of 0.1wt% Zn addition on the hardness and intermetallic formation on Cu substrate. For the hardness results, the micro Vickers values were reported. For intermetallic, the solders were melted at 250 o C and aged at 150 o C until 400 hours. The microhardness value for Zn based composites solder shows higher micro Vickers hardness compared to un-doped counterparts. The phases formed and its growth was studied under SEM and by energy dispensive x-ray (EDX). The SEM results show the presence of Cu 6 Sn 5 and Cu 3 Sn intermetallics and the Cu 5 Zn 8 intermetallic was not detected. The addition of 0.1wt% Zn has retarded the growth of the Cu 3 Sn intermetallic but not the total intermetallic thickness.
2012 35th IEEE/CPMT International Electronics Manufacturing Technology Conference (IEMT), 2012
Due to environmental concern regarding toxicity of leadbased solder, the lead-free solders were introduced as a replacing solder in microelectronics devices technology. In this study, the effects of 0.1, 0.4 and 0.7 wt% Zn additions on the intermetallic formation and thickness of Sn-3.5Ag-1.0Cu solder on Cu substrate after long time aging were investigated. The X-Ray Diffraction (XRD) analysis shown that there were Cu 6 Sn 5 , Cu 3 Sn, β-Sn, CuZn and Ag 3 Sn phase formed after sintering process. The morphology of the intermetallic was observed under Scanning Electron Microscope (SEM) and the elemental distribution was confirmed by Energy Dispersive X-ray (EDX). The intermetallic thickness increases as the aging temperature increases while the addition of zinc into the system has suppressed the intermetallic formation.
The effect of adding Zn into the Sn–Ag–Cu solder on the intermetallic growth rate
Journal of Materials Science: Materials in Electronics, 2014
Due to toxicity of lead in the commercial solder, lead-free solders were proposed. Among the potential leadfree solders, the SnAg -Cu solders were considered as a potential replacement. To further improve the solder properties, a fourth element was added into the SnAg -Cu solder. The present study investigates the effect of different weight percentage of Zn (up to 0.7 wt%) into the Sn-3.5Ag-1.0Cu solder on intermetallic and growth rate (k) after long time thermal aging. The solders were prepared using powder metallurgy method and X-ray diffraction analysis shows that there were Cu 6 Sn 5 , Cu 3 Sn, CuZn and Ag 3 Sn phases present after solder preparation. The solders were reacted with Cu substrate at 250°C for 1 min and aged at 150°C until 1,000 h. The morphology of the intermetallic was observed under scanning electron microscope and the elemental distribution was confirmed by energy dispersive X-ray. Intermetallic thickness and growth kinetic result show that the additions of 0.4 % zinc is sufficient in retarding the Cu 6 Sn 5 and Cu 3 Sn intermetallic growth.
2016
The need for replacing lead based solder has received great attention among researchers because of their toxicity. The Sn-Ag-Cu family is the most promising candidate. However, these solder systems need better improvement in terms of controlling their intermetallic formation, growth rate and also their mechanical properties. In this study, the Sn-3.5Ag-l.0Cu solder was studied and three different amounts of Zn were added into the solder system. The solder was prepared using powder metallurgy method. It was characterized for their melting temperature, hardness and density. For intermetallic study, the solder was melted at 250°C on a Cu substrate and placed in an oven at 150°C until 1000 h. After the aging process, the solder joint was cross-sectioned and analysed under a Scanning Electron Microscope and Energy Dispersive X-ray. The thickness of Cu₆Sn₅ and Cu₃ Sn intermetallics were measured using image J software and their growths kinetic were calculated. The shear joint specimen was...
Materials Science and Engineering: A, 2010
In the present study, the effects of separate and dual addition of small amount of Ag and Cu on the microstructure and mechanical properties of the eutectic Sn-9Zn solder alloy were investigated. Results indicate that alloying of Ag and/or Cu resulted in refine the coarse needle-like Zn-rich phase and formation of intermetallic compounds (IMCs) with the eutectic solder. Single addition of Ag led to formation of AgZn, Ag 5 Zn 8 and -AgZn 3 IMCs, which results in significant increase in both ultimate tensile strength (UTS) and ductility, while, the flower shaped and rod shaped Cu 6 Sn 5, ␥-Cu 5 Zn 8 and -CuZn 5 IMCs produced by Cu alloying, results in small increase in UTS and ductility. The dual addition of Ag and Cu suppressed the appearance of Ag 5 Zn 8 IMCs due to the competition for Zn between Cu and Ag, which results in slight decrease in UTS and ductility of Sn-9Zn-1.5Ag solder. Worthy of notice is that all alloys demonstrated an increase in both UTS and yield stress with increasing strain rate and/or decreasing testing temperature, indicating that the tensile behavior of the four alloys often exhibits a strain rate and temperature dependence.
Properties enhancement of low Ag-content Sn–Ag–Cu lead-free solders containing small amount of Zn
This study examines the effect of Zn addition on the microstructure, melt properties and tensile behavior of low Ag-content Sn–1.0Ag–0.3Cu (SAC103) lead-free solder. The results show that addition of 2.0 wt.% Zn to SAC(103) solder resulted in an excessive tensile strength and low ductility, which may be attributed to the dual effect of grain refinement and formation of course (Cu, Ag) 5 Zn 8 intermetallic compound (IMC) particles. Meanwhile, the alloy with 3.0 wt.% Zn exhibited both the highest strength and large ductility, which may be due to the high volume percentage of fine (Cu, Ag) 5 Zn 8 particles and fiber-like Ag 3 Sn precipitates. These eutectic micro-constituents contributed more significantly to the obstacles for disloca-tion pileup along the slip systems in Zn-containing SAC(103) solders, as it shows better deformation resistance than the plain SAC(103) solder. Besides, the addition of Zn not only reduced the liquidus and melting temperatures, but also decreased the undercooling and pasty range of SAC(103) solder.
Journal of Alloys and Compounds, 2010
Sn-9Zn with various additions of Sn-3.5Ag-0.5Cu powder was prepared by mechanically dispersing different weight percentages (1, 3, 5 and 7) of Sn-Ag-Cu powder into Sn-9Zn solder paste. In the Sn-Zn solder, scallop-shaped AuZn 3 intermetallic compound was found at the interfaces. On the other hand, in the Sn-3.5Ag-0.5Cu content solders, an additional e-AgZn 3 intermetallic compound layer was found to be well adhered on the top surface of the AuZn 3 layer and the e-AgZn 3 layer thickness increased with the number of reflow cycles. In addition, fine spherical-shaped e-AgZn 3 intermetallic compound particles as well as an acicular-shaped Zn-rich phase was clearly observed in the b-Sn matrix. On increasing the Sn-Ag-Cu content, the shear load was increased from 1.80 to 2.03 kg after one reflow cycle. In the Sn-3.5Ag-0.5Cu content solders, the fracture surfaces exhibited typical ductile behavior with very rough dimpled surfaces while the fracture surface in the Sn-Zn solder gave fractures with a brittle appearance. In the fracture surface of the Sn-3.5Ag-0.5Cu content solders, some dimples were clearly observed associated with the formation of spherical-shaped e-AgZn 3 intermetallic compound particles.
Influence of Bi on microstructures evolution and mechanical properties in Sn–Ag–Cu lead-free solder
Journal of Alloys and Compounds, 2004
Sn-Ag-Cu-Bi solders, which have high quality and performance that can meet the requirement of electronic packaging, have been investigated in this paper. The research was focused on the influence of aging on the microstructural evolution and mechanical properties in Sn-3Ag-0.5Cu-xBi (x = 0-3 wt.%) solders. The effect of Bi was discussed based on the experimental results. The experimental results indicated that the addition of Bi enhanced the tensile strength of the solders but decreased their elongation. After aging treatment, Sn-3Ag-0.5Cu solder showed significant change in strength and elongation which resulted from the obvious coarsening of Ag 3 Sn and Cu 6 Sn 5 intermetallics. As for Bi-bearing solders, Bi precipitation in Sn matrix was only observed in Sn-3Ag-0.5Cu-3Bi solder after being aged at 120 • C for 100 h, while all the Bi-bearing solders exhibited relatively stable mechanical properties with aging time which can be attributed to the strengthening effect of Bi from solid solution strengthening to precipitating strengthening.