Effects of antimony on the microstructure,thermal properties,mechanical performance,and interfacial behavior of Sn–0.7Cu–0.05Ni–xSb/Cu solder joints

Journal of Materials Science: Materials in Electronics - We investigated a new, lead-free solder alloy to replace traditional lead-based solder alloys. A Sn–0.7Cu–0.05Ni solder alloy...     

Growth mechanisms of intermetallic compounds and Bi-rich layer in ball grid array structure Cu/Sn-58Bi/Cu solder joints during solid–solid and liquid–solid electromigration

Journal of Materials Science: Materials in Electronics - Sn-58Bi solder has attracted much attention due to its low melting temperature and low cost in recent years. However, Sn-58Bi solder might...     

Effect of Ni and Co nanoparticle-doped flux on microstructure of SAC305 solder matrix

Microstructure of the eutectic region and β-Sn grain of the solder matrix play an important role in the properties of the Sn-based solder joint. In the present study, Ni and Co nanoparticle (NP)-doped flux were added into the SAC305 solder matrix to observe their effect on the microstructure of the eutectic region and β-Sn grain during the reflow process. Results reveal that after the addition of Ni and Co NP-doped flux, the size of β-Sn grain and the size of IMC particles present in the eutectic region significantly reduced. The area of the eutectic region also increased. Reduction in size of β-Sn grain and IMC particles improves the mechanical and structural properties of the solder joint.

     

Modeling the effects of temperature on the rheology of solder pastes and flux system

Solder paste is one of the most important process materials today in surface mount technology. Stencil printing of solder paste onto PCBs constitutes an important stage in the reflow soldering of surface mount devices. A high proportion of the solder-related defects can be attributed to the stencil printing process. This is likely to continue with the trend toward miniaturization and the implementation of die-size packages. To achieve repeatable solder deposits from board-to-board and pad-to-pad requires an understanding of the paste rheology. One of the key factors that influences solder paste rheology is temperature. A change in temperature will cause the viscosity of the solder paste to change. This change could be ambient or from the stencil printing process itself. This is likely to impact on the performance of the solder paste. In this paper, we present the effect of temperature on the rheological properties of solder paste and the flux vehicle system. Current models show a single variable dependence of viscosity with temperature. The model presented here incorporates shear rates and can be used for any solder paste or non-Newtonian material. The effects of temperature on solder paste flux medium, particle size and distribution, and metal alloy content are also presented.     

A review on nanodispersed lead-free solders in electronics: synthesis,microstructure and intermetallic growth characteristics

Journal of Materials Science - Lead-free solder research has witnessed a great jump in the past decades due to the increased restrictions over the use of toxic lead-bearing solder alloys. Among the...     

Wettability and interfacial whiskers of Sn–9Zn–0.5Ga–0.08Nd solder with Sn,SnBi and Au/Ni coatings

The wettability and interfacial whiskers of Sn–9Zn–0.5Ga–0.08Nd solder were investigated. The results indicated that Sn–9Zn–0.5Nd–0.08Nd solder has shown good wettability using water soluble flux and self made flux based on wetting balance testing, and solder with SnBi coating has shown superiority wettability among all three coatings. Moreover, no whisker was observed in Sn–9Zn–0.5Ga–0.08Nd solder with different coatings. But in Sn–9Zn–0.5Ga–1Nd solder, fewer whiskers were observed in solder with SnBi coating compared with Sn and Au/Ni coatings, which can be attributed to the refinement effect of Bi.     

Metallurgically and mechanically reliable microsilver-sintered joints for automotive power module applications

Journal of Materials Science: Materials in Electronics - Conventional soldering methods with Pb-containing and Pb-free solder alloys have been extensively used in the manufacturing of the power...     

Investigation on Cu–Sn intermetallic compounds growth and signal transmission loss of the diverse copper lines after soldering in printed circuit board

Journal of Materials Science: Materials in Electronics - The growth of IMCs at solder/substrate interface becomes more important with the sustaining advancement of integrated circuit technology....     

Effects of Bi content on thermal,microstructure and mechanical properties of Sn-Bi-In-Zn solder alloy systems

Journal of Materials Science: Materials in Electronics - In the present study, various amounts of Bi were added to two groups of Sn-In-Zn lead-free solder alloy systems (Sn-[x] Bi-2In-9Zn...     

Interface behavior and performance of Sn–Ag–Cu lead-free solder bearing Tb

Journal of Materials Science: Materials in Electronics - To further improve the performance of the Sn–3.5Ag–0.5Cu solder, trace amount of rare earth Tb was added. The wettability, shear...     

Effect of Ni-coated carbon nanotubes addition on the wettability,microhardness, and shear strength of Sn-3.0Ag-0.5Cu/Cu lead-free solder joints

Journal of Materials Science: Materials in Electronics - Sn-3.0Ag-0.5Cu lead-free solder reinforced with different mass fractions (0, 0.05, 0.1, 0.2, 0.5 wt%) of Ni-coated carbon nanotubes...     

Bubble formation and growth during Transient Liquid Phase Bonding in Cu/SnAg system for microelectronic packaging

Journal of Materials Science: Materials in Electronics - In this work, we study the Transient Liquid Phase Bonding (TLPB) for flip chip interconnexion using copper pillar and SnAg solder alloy...     

Influence of phase inhomogeneity on the mechanical behavior of microscale Cu/Sn–58Bi/Cu solder joints

Journal of Materials Science: Materials in Electronics - Electronics are becoming smaller and more versatile, and the size of solder joints has decreased to tens of microns, inducing obvious...     

Effect of water on the dielectric behavior of solder

Journal of Materials Science: Materials in Electronics - The electrical conduction behavior of solder is well-known, but the dielectric behavior has been reported only recently. Water in the...     

Effect of Diamond Additions on Wettability and Distribution of SnAgCu Composite Solder

Diamond/SnAgCu composite solder bumps were prepared on Cu pad by mechanically incorporating diamond particles into Sn3.0Ag0.5Cu(SAC) solder powders,mixing with flux and reflowing at 260 ℃ for 60 s.The spreading areas of composite solder were calculated and the distributions of copper-coated diamonds were characterized.When diamond additions were below 3 wt%,the spreading area decreased with diamond additions,and the diamonds distributed mainly at the interface between solder and Cu pad;however,when additions were beyond 4 wt%,the discharge of diamond particle occurred,and the spreading area increased due to the reduction of surface energy.     

Investigation of Sn–Bi–In ternary solders with compositions varying from Sn–Bi eutectic point to 76 °C ternary eutectic

Journal of Materials Science: Materials in Electronics - The solder properties of Sn–Bi–In ternary solders of seven different compositions are examined. The compositions are...     

Thermal contact at solder/substrate interfaces during solidification

Abstract

Heat flux transients at the solder/substrate interface during the solidification of Sn–37Pb and Sn–3·5Ag solder alloys against metallic substrates were estimated by the lumped heat capacitance model and the contact condition was assessed by scanning electronic microscopy (SEM). Copper substrates yielded maximum contact heat flux followed by brass and aluminium substrates. The SEM study in the solder/substrate interfacial region revealed the existence of a clear gap with the aluminium substrate. A conforming contact was obtained with copper and brass substrates.     

Recent advances on SnBi low-temperature solder for electronic interconnections

Journal of Materials Science: Materials in Electronics - SnBi lead-free solder is widely applied in the field of low-temperature soldering due to its excellent creep resistance, relatively low...     

Effects of reflow atmosphere and flux on Sn whisker growth of Sn–Ag–Cu solders

We evaluated the Sn whisker growth behavior of Sn–Ag–Cu solder fillets on lead frames of quad flat packages (QFPs) upon OSP printed circuit boards that were exposed to 85 °C/85% relative humidity (RH) exposure. Three different concentrations of halogen flux for activated Sn-3.0wt%Ag–0.5wt%Cu were used to solder in air and in an inert N₂ reflow atmosphere. The lead frames of the QFPs consisted of Sn plated Cu and Fe-42wt%Ni (alloy 42). Sn whiskers were observed on the surface of the QFP solder fillet joints that were reflowed with halogen containing flux in an air atmosphere. A substantial amount of Sn oxides were formed in those solder fillets while whisker growth and the amount of Sn oxides increased with the halogen content. Sn oxide formation apparently enhanced whisker formation. The combination of air reflow atmosphere and high halogen flux was the worst combination for solder fillet oxidation resulting in Sn whisker formation regardless of the electrode’s lead frame composition of Cu or alloy 42. In contrast, an inert N₂ reflow atmosphere obviously prevented Sn whisker formation on Sn–Ag–Cu solder fillets under all conditions used in this work.     

Geometrical size effect on the interface diffusion of micro solder joint in electro-thermal coupling aging

This paper investigates the influence of diffusion layer (solder layer) thickness (δ) on interface diffusion in both thermal aging and electro-thermal coupling aging. The different δ (δ = 60, 120 and 240 μm) of Cu/Sn–3.0Ag–0.5Cu (SAC305)/Cu butt solder joints are used. The results indicate that the geometrical size (solder layer thickness) of solder joint has significant effect on element diffusion behavior. The diffusion coefficient, time exponent, element concentrations and diffusion flux are greatly dependent upon δ. The effects of δ on the interface diffusion is different between thermal aging and electro-thermal coupling aging, due to driving force for diffusion is different. During thermal aging, concentration gradient is the main driving force of diffusion, and diffusion coefficient, time exponent and diffusion flux are relatively low for a thin solder layer. However, under electro-thermal coupling condition, the electron wind force provides the dominating driving force for diffusion, and diffusion coefficient and diffusion flux of thin δ are significantly larger than the thick ones. The Cu concentration of the area near interface is relatively high for a thin solder layer in both tests. Under the same experimental temperature, the effects of δ on the electro-thermal coupling aging are more obvious than thermal aging.