Effect of nano-Cu addition on microstructure evolution of Sn0.7Ag0.5Cu-BiNi/Cu solder joint

2017 ◽  
Vol 29 (2) ◽  
pp. 92-98 ◽  
Author(s):  
Gaofang Ban ◽  
Fenglian Sun ◽  
Yang Liu ◽  
Shaonan Cong

Purpose The purpose of this paper is to focus on the fabrication of SnAgCu (SAC) nanocomposites solder and study the effect of Cu nanopowders (nano-Cu) addition on the microstructure evolution of resultant nanocomposite solder after reflow and thermal aging. Design/methodology/approach Mechanical mixing is used in this work to incorporate nanoparticles into the solder and produce more homogeneous mixture. Standard metallographic procedures are applied for microstructural analysis of solder joints. Findings It is found that nano-Cu doped into Sn0.7Ag0.5Cu-BiNi solder has no appreciable influence on melting temperature of the composite solder. The addition of Cu nanoparticles refines the microstructure of bulk solder and suppresses the growth of interfacial intermetallic compound (IMC) layers. However, interfacial IMC grain size increases slightly after 1.0 per cent nano-Cu added. Originality/value The paper demonstrates a method of nano-composite solder paste preparation by means of mechanical mixing and a comparison study of the microstructure evolution of composite solder with the basic SAC solder.

2017 ◽  
Vol 34 (1) ◽  
pp. 40-44 ◽  
Author(s):  
Hao Zhang ◽  
Yang Liu ◽  
Fenglian Sun ◽  
Gaofang Ban ◽  
Jiajie Fan

Purpose This paper aimed to investigate the effects of nano-copper particles on the melting behaviors, wettability and defect formation mechanism of the Sn58Bi composite solder pastes. Design/methodology/approach In this paper, the mechanical stirring method was used to get the nano-composite solder pastes. Findings Experimental results indicated that the addition of 3 wt.% (weight percentage) 50 nm copper particles showed limited effects on the melting behaviors of the Sn58Bi composite solder paste. The spreading rate of the Sn58Bi composite solder paste showed a decreasing trend with the increase of the weight percentage of 50 nm copper particles from 0 to 3 wt.%. With the addition of copper particles of diameters 50 nm, 500 nm or 6.5 μm into the Sn58Bi solder paste, the porosities of the three types of solder pastes showed a similar trend. The porosity increased with the increase of the weight percentage of copper particles. Based on the experimental results, a model of the void formation mechanism was proposed. During reflow, the copper particles reacted with Sn in the matrix and formed intermetallic compounds, which gathered around the voids produced by the volatilization of flux. The exclusion of the voids was suppressed and eventually led to the formation of defects. Originality/value This study provides an optimized material for the second and third level packaging. A model of the void formation mechanism was proposed.


2018 ◽  
Vol 280 ◽  
pp. 206-211 ◽  
Author(s):  
Rita Mohd Said ◽  
Mohd Arif Anuar Mohd Salleh ◽  
Nur Ain Athirah Amran ◽  
Mohd Izrul Izwan Ramli

The evolution in microstructure of Sn-Cu based solder paste with different copper (Cu) content subjected to multiple reflow cycles was investigated. In this study, the Sn-0.7Cu (SC) solder paste was used as based material. The Cu particles were added into SC solder paste to produce new Sn-4Cu and Sn-10Cu solder paste. After that, the solder paste was then reflowed on Cu-OSP surface finished and subjected to six times reflows. Characterization focuses on the bulk solder microstructure, morphology and intermetallic compound (IMC) thickness after multiple reflows. Results reveal that solder composition significantly affect the microstructure formation and growth of IMC.


2014 ◽  
Vol 26 (3) ◽  
pp. 147-161 ◽  
Author(s):  
Ervina Efzan Mhd Noor ◽  
Amares Singh

Purpose – The aim of the present study was to gather and review all the important properties of the Sn–Ag–Cu (SAC) solder alloy. The SAC solder alloy has been proposed as the alternative solder to overcome the environmental concern of lead (Pb) solder. Many researchers have studied the SAC solder alloy and found that the properties such as melting temperature, wettability, microstructure and interfacial, together with mechanical properties, are better for the SAC solder than the tin – lead (SnPb) solders. Meanwhile, addition of various elements and nanoparticles seems to produce enhancement on the prior bulk solder alloy as well. These benefits suggest that the SAC solder alloy could be the next alternative solder for the electronic packaging industry. Although many studies have been conducted for this particular solder alloy, a compilation of all these properties regarding the SAC solder alloy is still not available for a review to say. Design/methodology/approach – Soldering is identified as the metallurgical joining method in electronic packaging industry which uses filler metal, or well known as the solder, with a melting point < 425°C (Yoon et al., 2009; Ervina and Marini, 2012). The SAC solder has been developed by many methods and even alloying it with some elements to enhance its properties (Law et al., 2006; Tsao et al., 2010; Wang et al., 2002; Gain et al., 2011). The development toward miniaturization, meanwhile, requires much smaller solder joints and fine-pitch interconnections for microelectronic packaging in electronic devices which demand better solder joint reliability of SAC solder Although many studies have been done based on the SAC solder, a review based on the important characteristics and the fundamental factor involving the SAC solder is still not sufficient. Henceforth, this paper resolves in stating all its important properties based on the SAC solder including its alloying of elements and nanoparticles addition for further understanding. Findings – Various Pb-free solders have been studied and investigated to overcome the health and environmental concern of the SnPb solder. In terms of the melting temperature, the SAC solder seems to possess a high melting temperature of 227°C than the Pb solder SnPb. Here, the melting temperature of this solder falls within the range of the average reflow temperature in the electronic packaging industry and would not really affect the process of connection. A good amendment here is, this melting temperature can actually be reduced by adding some element such as titanium and zinc. The addition of these elements tends to decrease the melting temperature of the SAC solder alloy to about 3°C. Adding nanoparticles, meanwhile, tend to increase the melting temperature slightly; nonetheless, this increment was not seemed to damage other devices due to the very slight increment and no drastic changes in the solidification temperature. Henceforth, this paper reviews all the properties of the Pb-free SAC solder system by how it is developed from overcoming environmental problem to achieving and sustaining as the viable candidate in the electronic packaging industry. The Pb-free SAC solder can be the alternative to all drawbacks that the traditional SnPb solder possesses and also an upcoming new invention for the future needs. Although many studies have been done in this particular solder, not much information is gathered in a review to give better understanding for SAC solder alloy. In that, this paper reviews and gathers the importance of this SAC solder in the electronic packaging industry and provides information for better knowledge. Originality/value – This paper resolves in stating of all its important properties based on the SAC solder including its alloying of elements and nanoparticles addition for further understanding.


2006 ◽  
Vol 312 ◽  
pp. 237-242 ◽  
Author(s):  
Xiao Ping Zhang ◽  
C.S.H. Lim ◽  
Yiu Wing Mai ◽  
Yao Wu Shi

Thermal fatigue performance and creep resistance of soldered connections are crucial to the integrity and reliability of microelectronics, optoelectronics and photonics packaging systems. In this work, creep and thermal fatigue behaviours of lap shear joints soldered by a tin-based nanocomposite solder were characterized at different temperatures, with a comparison to a traditional Sn60Pb40 solder. The results show that the nano-composite solder has much better creep resistance and thermal creep fatigue property than the Sn60Pb40 solder. This is mainly due to the uniformly dispersed nano-sized Ag particles that have provided effective impediment to dislocation movement and grain boundary sliding, in addition to the alloying effect. The creep fractography analysis by SEM shows that a progressive shear deformation occurred as the main creep fracture mechanism. Sn60Pb solder joints deform dominantly by transgranular sliding, while the nano-composite solder joints creep by intergranular mechanism through grain boundary sliding and voids growth.


2013 ◽  
Vol 288 ◽  
pp. 323-327 ◽  
Author(s):  
Y. Zhong ◽  
W. Zhang ◽  
C.Q. Wang ◽  
B. Li

Diamonds/SnAgCu composite solder bumps were prepared on Cu pad by mechanically incorporating diamond particles into Sn3.0Ag0.5Cu (SAC) solder paste and then reflowed at 260°C for 60s. Chemical copper plating method was proved to be an efficient way to achieve high addition amount of diamond particles (> 1 wt.%, which is much better than former studies) in solder, and to get solder bumps with better morphology. The spreading rate of this novel solder was turned out to be acceptable in operating range. Shear strength and microstructure of composite solder bumps were studied, showing that they could be influenced by the changes in morphology of the Ag3Sn net work caused by the various additions of Cu coated diamond particles.


2016 ◽  
Vol 28 (2) ◽  
pp. 84-92 ◽  
Author(s):  
Guang Chen ◽  
Bomin Huang ◽  
Hui Liu ◽  
Y.C. Chan ◽  
Zirong Tang ◽  
...  

Purpose The purpose of this paper is to investigate microstructure and properties of Sn3.0Ag0.5Cu-XAl2O3 composite solder which were prepared through powder metallurgy route. Design/methodology/approach Sn3.0Ag0.5Cu (SAC305)-XAl2O3 (X = 0.2, 0.4, 0.6, 0.8 Wt. %) composite solders were prepared through the powder metallurgy route. The morphology of composite solder powders which consists of Al2O3 particles and SAC solder powders after ball milling was observed. The retained ratio of Al2O3 nanoparticles in composite solder billets and solder joints were also quantitatively measured. Furthermore, the as-prepared composite solder alloys were studied extensively with regard to their microstructures, thermal property, wettability and mechanical properties. Findings After ball milling, the Al2O3 nanoparticles added were observed embedded into the surface of SAC solder powders. Only about 5-10 per cent of the initial Al2O3 nanoparticles added were detected in the composite solder joints after reflow. In addition, finer ß-Sn grains were achieved with addition of Al2O3 nanoparticles; the Al2O3 nanoparticles were found retained in the composite solder matrix. Besides, negligible changes in melting temperature and the considerably reduced undercooling were obtained in composite solder alloys. Wettability was improved by appropriate addition of Al2O3 nanoparticles. Microhardness and shear strength of composite solders were both improved after Al2O3 nanoparticles addition. Originality/value This paper indicated that powder metallurgy route offered a feasible approach to produce nanoparticle reinforced composite solder. In addition, the quantitative analysis of the actual retained ratio of the Al2O3 nanoparticles in solder joints provided practical implications for the manufacture of composite solders.


2020 ◽  
Vol 33 (1) ◽  
pp. 47-56
Author(s):  
Norliza Ismail ◽  
Azman Jalar ◽  
Maria Abu Bakar ◽  
Nur Shafiqa Safee ◽  
Wan Yusmawati Wan Yusoff ◽  
...  

Purpose The purpose of this paper is to investigate the effect of carbon nanotube (CNT) addition on microstructure, interfacial intermetallic compound (IMC) layer and micromechanical properties of Sn-3.0Ag-0.5Cu (SAC305)/CNT/Cu solder joint under blast wave condition. This work is an extension from the previous study of microstructural evolution and hardness properties of Sn-Ag-Cu (SAC) solder under blast wave condition. Design/methodology/approach SAC/CNT solder pastes were manufactured by mixing of SAC solder powder, fluxes and CNT with 0.02 and 0.04 by weight percentage (Wt.%) separately. This solder paste then printed on the printed circuit board (PCB) with the copper surface finish. Printed samples underwent reflow soldering to form the solder joint. Soldered samples then exposed to the open field air blast test with different weight charges of explosives. Microstructure, interfacial IMC layer and micromechanical behavior of SAC/CNT solder joints after blast test were observed and analyzed via optical microscope, field emission scanning microscope and nanoindentation. Findings Exposure to the blast wave induced the microstructure instability of SAC305/Cu and SAC/CNT/Cu solder joint. Interfacial IMC layer thickness and hardness properties increases with increase in explosive weight. The existence of CNT in the SAC305 solder system is increasing the resistance of solder joint to the blast wave. Originality/value Response of micromechanical properties of SAC305/CNT/Cu solder joint has been identified and provided a fundamental understanding of reliability solder joint, especially in extreme conditions such as for military applications.


2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
F Sun ◽  
Zhen Pan ◽  
Yang Liu ◽  
Xiang Li ◽  
Haoyu Liu ◽  
...  

Purpose The purpose of this paper is to quickly manufacture full Cu3Sn-microporous copper composite joints for high-temperature power electronics applications and study the microstructure evolution and the shear strength of Cu3Sn at different bonding times. Design/methodology/approach In this paper, a novel structure of Cu/composite solder sheet/Cu was designed. The composite solder sheet was made of microporous copper filled with Sn. The composite joint was bonded by thermo-compression bonding under pressure of 0.6 MPa at 300°C. The microstructure evolution and the growth behavior of Cu3Sn at different bonding times were observed by electron microscope and metallographic microscope. The shear strength of the joint was measured by shear machine. Findings At initial bonding stage the copper atoms in the substrate and the copper atoms in the microporous copper dissolved into the liquid Sn. Then the scallop-liked Cu6Sn5 phases formed at the interface of liquid Sn/microporous copper and liquid Sn/Cu substrates. During the liquid Sn changing to Cu6Sn5 phases, Cu3Sn phases formed and grew at the interface of Cu6Sn5/Cu substrates and Cu6Sn5/microporous copper. After that the Cu3Sn phases continued to grow and the Cu3Sn-microporous copper composite joint with a thickness of 100 µm was successfully obtained. The growth rule of Cu3Sn was parabolic growth. The shear strength of the composite joints was about 155 MPa. Originality/value This paper presents a novel full Cu3Sn-microporous copper composite joint with high shear strength for high-temperature applications based on transient liquid phase bonding. The microstructure evolution and the growth behavior of Cu3Sn in the composite joints were studied. The shear strength and the fracture mechanism of the composite joints were studied.


2012 ◽  
Vol 24 (3) ◽  
pp. 839-847 ◽  
Author(s):  
A. Roshanghias ◽  
A. H. Kokabi ◽  
Y. Miyashita ◽  
Y. Mutoh ◽  
H. R. Madaah Hosseini

Crystals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 733
Author(s):  
Lu Liu ◽  
Songbai Xue ◽  
Ruiyang Ni ◽  
Peng Zhang ◽  
Jie Wu

In this study, a Sn–Bi composite solder paste with thermosetting epoxy (TSEP Sn–Bi) was prepared by mixing Sn–Bi solder powder, flux, and epoxy system. The melting characteristics of the Sn–Bi solder alloy and the curing reaction of the epoxy system were measured by differential scanning calorimeter (DSC). A reflow profile was optimized based on the Sn–Bi reflow profile, and the Organic Solderability Preservative (OSP) Cu pad mounted 0603 chip resistor was chosen to reflow soldering and to prepare samples of the corresponding joint. The high temperature and humidity reliability of the solder joints at 85 °C/85% RH (Relative Humidity) for 1000 h and the thermal cycle reliability of the solder joints from −40 °C to 125 °C for 1000 cycles were investigated. Compared to the Sn–Bi solder joint, the TSEP Sn–Bi solder joints had increased reliability. The microstructure observation shows that the epoxy resin curing process did not affect the transformation of the microstructure. The shear force of the TSEP Sn–Bi solder joints after 1000 cycles of thermal cycling test was 1.23–1.35 times higher than the Sn–Bi solder joint and after 1000 h of temperature and humidity tests was 1.14–1.27 times higher than the Sn–Bi solder joint. The fracture analysis indicated that the cured cover layer could still have a mechanical reinforcement to the TSEP Sn–Bi solder joints after these reliability tests.


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