DEVELOPMENT OF NOVEL LEAD-FREE SOLDER COMPOSITES USING CARBON NANOTUBE REINFORCEMENTS

In this study, Sn - Ag - Cu based nanocomposites with carbon nanotubes (CNTs) as reinforcements were successfully synthesized via the powder metallurgy technique. Lead-free solder powders were firstly blended together with varying weight percentages of CNTs. The materials were then compacted, sintered and finally extruded at room temperature. The extruded materials were characterized for their microstructural, thermal and mechanical properties. The porosity of the nanocomposites was observed to increase with increasing weight percentages of CNTs, accordingly the density of the nanocomposites was reduced. Thermomechanical analysis of the solder nanocomposites showed that the use of CNTs as reinforcements decreased the average coefficient of thermal expansion of the solder matrix. Furthermore, the results of mechanical properties characterization revealed that the addition of CNTs aids in enhancing the microhardness and the overall strength of the nanocomposite solder. An attempt is made in the present study to correlate the variation in weight percentages of the carbon nanotubes with the properties of the resultant nanocomposite materials.

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Effect of Presence of Carbon Nanotubes on the Wettability and Mechanical Performance of Sn-Ag-Cu Solder

Electronic and Photonic Packaging, Electrical Systems Design and Photonics, and Nanotechnology ◽

10.1115/imece2005-79457 ◽

2005 ◽

Cited By ~ 1

Author(s):

S. M. L. Nai ◽

J. Wei ◽

Manoj Gupta

Keyword(s):

Mechanical Properties ◽

Carbon Nanotubes ◽

Flip Chip ◽

Composite Solder ◽

Mechanical Performance ◽

Melting Temperatures ◽

Micron Size ◽

Free Solder ◽

Mechanical Properties Characterization ◽

Made In

In this study, Sn-Ag-Cu based nanocomposites with carbon nanotubes (CNTs) as reinforcements were successfully synthesized using the powder metallurgy technique. Micron size lead-free solder particles were blended together with varying weight percentages of CNTs. Blended powder mixtures were then compacted, sintered and finally extruded at room temperature. The extruded materials were characterized for their melting temperatures, wettability and mechanical properties. Experimental results revealed that the melting temperatures of the composite solders did not have any significant changes. Wettability property of the composite solder was also found to improve with addition of reinforcements. Moreover, the results of mechanical properties characterization exhibited an increase in overall strength of the composite solders. An attempt is made in the present study to correlate the variation in weight percentages of reinforcement with the properties of the resultant nanocomposite materials. These advanced interconnect materials will benefit industries like the microelectronics flip chip assembly and packaging, MEMS systems and NEMS systems.

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Effects of Shear Cycling on the Mechanical Properties of SAC and SAC+X Lead Free Solder Joints

ASME 2019 International Technical Conference and Exhibition on Packaging and Integration of Electronic and Photonic Microsystems ◽

10.1115/ipack2019-6567 ◽

2019 ◽

Cited By ~ 2

Author(s):

Mohd Aminul Hoque ◽

Md Mahmudur Chowdhury ◽

Sa’d Hamasha ◽

Jeffrey C. Suhling ◽

Pradeep Lall

Keyword(s):

Mechanical Properties ◽

Solder Joints ◽

Coefficient Of Thermal Expansion ◽

Real Life ◽

Material Behavior ◽

Lead Free ◽

Lead Free Solder ◽

Cyclic Shear ◽

Mechanical Cycling ◽

Free Solder

Abstract Solder joint reliability is a chief concern in electronic assemblies. Electronic packages consist of various materials, each having their own Coefficient of Thermal Expansion (CTE). When assembled packages experience high temperature gradients and thermal cycles, a mismatch in the CTE values brings about cyclic shear strains in the solder joints, which can ultimately lead to failure. Thus, it is important to understand the effects of shear cycling on the damage accumulated in solder joints. Previous studies conducted on the effect of mechanical cycling on the material behavior of lead free solders have been performed on bulk samples subjected to tension and compression. Our goal in this study was to determine the evolution of the mechanical properties of doped lead free solder joints when subjected to mechanical shear cycling. Experiments conducted on actual solder joints would help us gain a better understanding on the real life effects of shear cycling. The test specimens consisted of a 3 × 3 array of nine solder joints of approximately 0.75 mm diameter. With the aid of specially designed test fixtures, the specimens were gripped and then subjected to mechanical cycling in the shear using an Instron Micromechanical tester. Testing was performed on both SAC305 and SACX (SAC+Bi) solder joints. The joints were cycled for certain durations, and a nanoindentation system was used to measure the evolution of the mechanical properties (elastic modulus, hardness, creep rate) as a function of the number of shear cycles.

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Development of Lead-Free Solder Composites Containing Nanosized Hybrid (ZrO2 + 8 mol.% Y2O3) Particulates

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.111.59 ◽

2006 ◽

Vol 111 ◽

pp. 59-62 ◽

Cited By ~ 10

Author(s):

Sharon M.L. Nai ◽

Jun Wei ◽

Manoj Gupta

Keyword(s):

Coefficient Of Thermal Expansion ◽

Thermomechanical Analysis ◽

Lead Free ◽

Microstructural Development ◽

Thermal And Mechanical Properties ◽

Average Coefficient ◽

Density Values ◽

Free Solder ◽

Nanocomposite Solder ◽

Made In

In this study, lead-free composite solders were successfully synthesized, with varying amount of nanosized ZrO2 + 8 mol.% Y2O3 particulates incorporated into 95.8 Sn – 3.5 Ag – 0.7 Cu solder. These composite materials were fabricated using the powder metallurgy technique involving blending, compaction, sintering and extrusion. The extruded materials were then characterized in terms of their physical properties, microstructural development, thermal and mechanical properties. Experimental results revealed that with the addition of increasing amount of reinforcements, the density values of the composite solders decreased, but there was no influence on the melting point of the composite solders. Thermomechanical analysis of the solder nanocomposites showed that the use of reinforcements lowered the average coefficient of thermal expansion of the solder material. Moreover, the results of mechanical property characterizations revealed that the addition of reinforcements aids in improving the overall strength of the nanocomposite solder. An attempt is made in the present study to correlate the variation in volume percentages of the hybrid reinforcements with the properties of the resultant nanocomposite materials.

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Effect of Terbium Additions on Microstructural, Thermal and Mechanical Properties of Eutectic Sn-3.5Ag Pb- Free Solder for Low Cost Electronic Assembly

JOURNAL OF ADVANCES IN PHYSICS ◽

10.24297/jap.v16i1.8239 ◽

2019 ◽

Vol 16 (1) ◽

pp. 79-94

Author(s):

Rizk Mostafa Shalaby ◽

Fatma Elzahraa Ibrahim ◽

Mostafa Kamal

Keyword(s):

Mechanical Properties ◽

Rare Earth ◽

Earth Element ◽

Low Cost ◽

Solder Matrix ◽

Lead Free ◽

Lead Free Solder ◽

Thermal And Mechanical Properties ◽

Electronic Assembly ◽

Free Solder

This work methodically concentrated on the effect of a trace amount of rare earth element terbium, Tb (0.1, 0.2, 0.3, 0.4 and 0.5 wt. %) on the properties of eutectic Sn-3.5 wt. %Ag were studied. The results indicated that addition of Tb rare earth can be refined the microstructure of the solder and intermetallic compound (IMC) Ag3Sn phase appeared in the solder matrix. Add a few quantity of rare earth Tb enhances the hardness and strength of eutectic Sn-Ag lead free solder joint. Also, results indicate that adding Tb to the eutectic Sn-3.5Ag remarkably enhances solderability, reliability, thermal and mechanical properties. It is also found that increasing in mechanical strength can depend on crystalline size refining in addition to some regular precipitates from IMC, Ag3Sn.

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Effect of aluminum content on structure, transport and mechanical properties of Sn-Zn eutectic lead free solder alloy rapidly solidified from melt.

JOURNAL OF ADVANCES IN PHYSICS ◽

10.24297/jap.v10i1.1343 ◽

2015 ◽

Vol 10 (1) ◽

pp. 2641-2648

Author(s):

Rizk Mostafa Shalaby ◽

Mohamed Munther ◽

Abu-Bakr Al-Bidawi ◽

Mustafa Kamal

Keyword(s):

Mechanical Properties ◽

Melting Point ◽

Lead Free ◽

Al Alloy ◽

Lead Free Solder ◽

Pronounced Increase ◽

Mass Unit ◽

Size Refinement ◽

Free Solder ◽

Lead Free Solders

The greatest advantage of Sn-Zn eutectic is its low melting point (198 oC) which is close to the melting point. of Sn-Pb eutectic solder (183 oC), as well as its low price per mass unit compared with Sn-Ag and Sn-Ag-Cu solders. In this paper, the effect of 0.0, 1.0, 2.0, 3.0, 4.0, and 5.0 wt. % Al as ternary additions on melting temperature, microstructure, microhardness and mechanical properties of the Sn-9Zn lead-free solders were investigated. It is shown that the alloying additions of Al at 4 wt. % to the Sn-Zn binary system lead to lower of the melting point to 195.72 ËšC.Â From x-ray diffraction analysis, an aluminium phase, designated Î±-Al is detected for 4 and 5 wt. % Al compositions. The formation of an aluminium phase causes a pronounced increase in the electrical resistivity and microhardness. The ternary Sn-9Zn-2 wt.%Al exhibits micro hardness superior to Sn-9Zn binary alloy. The better Vickers hardness and melting points of the ternary alloy is attributed to solid solution effect, grain size refinement and precipitation of Al and Zn in the Sn matrix.Â The Sn-9%Zn-4%Al alloy is a lead-free solder designed for possible drop-in replacement of Pb-Sn solders.Â Â

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Distribution and Microstructure Analysis of Ceramic Particles in the Lead-Free Solder Matrix

10.21203/rs.3.rs-36424/v1 ◽

2020 ◽

Author(s):

Manoj Kumar Pal ◽

Gréta Gergely ◽

Dániel Koncz-Horváth ◽

Zoltán Gácsi

Keyword(s):

Silicon Carbide ◽

Intermetallic Compounds ◽

Solder Alloy ◽

Solder Matrix ◽

Microstructure Analysis ◽

Lead Free ◽

Lead Free Solder ◽

Sac305 Solder ◽

Small Change ◽

Free Solder

Abstract The Sn-3.0Ag-0.5Cu solder alloy is a prominent candidate for the Pb-free solder, and SAC305 solder is generally employed in today’s electronic enterprise. In this study, the formation of intermetallic compounds (Cu6Sn5 and Ag3Sn) at the interface, average neighbour’s particle distance, and the morphological mosaic are examined by the addition of SiC and nickel-coated silicon carbide reinforcements within Sn-3.0Ag-0.5Cu solder. Results revealed that the addition of SiC and SiC(Ni) particles are associated with a small change to the average neighbor’s particle distance and a decrease of clustering rate to a certain limit of the Sn-3.0Ag-0.5Cu solder composites. Moreover, the development of the Cu6Sn5 and the structure of the Ag3Sn are improved with the addition of SiC and Ni coated SiC.

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Solder Joint Reliability of Sn-Cu and Sn-Ag-Cu Lead-Free Solder Alloys Solidified on Copper Substrates with Different Surface Roughnesses

Materials Science Forum ◽

10.4028/www.scientific.net/msf.830-831.265 ◽

2015 ◽

Vol 830-831 ◽

pp. 265-269

Author(s):

Satyanarayan ◽

K.N. Prabhu

Keyword(s):

Solder Joint ◽

Solder Matrix ◽

Lead Free ◽

Lead Free Solder ◽

Solder Alloys ◽

Cu Substrate ◽

Cu Substrates ◽

Free Solder ◽

Substrate Surfaces ◽

Lead Free Solders

In the present work, the bond strength of Sn-0.7Cu, Sn-0.3Ag-0.7Cu, Sn-2.5Ag-0.5Cu and Sn-3Ag-0.5Cu lead free solders solidified on Cu substrates was experimentally determined. The bond shear test was used to assess the integrity of Sn–Cu and Sn–Ag–Cu lead-free solder alloy drops solidified on smooth and rough Cu substrate surfaces. The increase in the surface roughness of Cu substrates improved the wettability of solders. The wettability was not affected by the Ag content of solders. Solder bonds on smooth surfaces yielded higher shear strength compared to rough surfaces. Fractured surfaces revealed the occurrence of ductile mode of failure on smooth Cu surfaces and a transition ridge on rough Cu surfaces. Though rough Cu substrate improved the wettability of solder alloys, solder bonds were sheared at a lower force leading to decreased shear energy density compared to the smooth Cu surface. A smooth surface finish and the presence of minor amounts of Ag in the alloy improved the integrity of the solder joint. Smoother surface is preferable as it favors failure in the solder matrix.

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Nanoindentation Characterization of Lead-free Solders and Intermetallic Compounds under Thermal Aging

International Symposium on Microelectronics ◽

10.4071/isom-2010-tp4-paper5 ◽

2010 ◽

Vol 2010 (1) ◽

pp. 000314-000318

Author(s):

Tong Jiang ◽

Fubin Song ◽

Chaoran Yang ◽

S. W. Ricky Lee

Keyword(s):

Mechanical Properties ◽

Thermal Aging ◽

Solder Joints ◽

Lead Free ◽

Small Range ◽

Lead Free Solder ◽

Solder Alloys ◽

Aging Test ◽

Free Solder ◽

Lead Free Solders

The enforcement of environmental legislation is pushing electronic products to take lead-free solder alloys as the substitute of traditional lead-tin solder alloys. Applications of such alloys require a better understanding of their mechanical behaviors. The mechanical properties of the lead-free solders and IMC layers are affected by the thermal aging. The lead-free solder joints on the pads subject to thermal aging test lead to IMC growth and cause corresponding reliability concerns. In this paper, the mechanical properties of the lead-free solders and IMCs were characterized by nanoindentation. Both the Sn-rich phase and Ag3Sn + β-Sn phase in the lead-free solder joint exhibit strain rate depended and aging soften effect. When lead-free solder joints were subject to thermal aging, Young's modulus of the (Cu, Ni)6Sn5 IMC and Cu6Sn5 IMC changed in very small range. While the hardness value decreased with the increasing of the thermal aging time.

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