Flora Somidin

Intermetallic Compound Formation on Solder Alloy/Cu-Substrate Interface Using Lead-Free Sn-0.7Cu/Recycled-Aluminum Composite Solder

Feasibility of using recycled-Aluminum (re-Al) as reinforcement particulates in Sn-0.7Cu is assessed by powder technology method, whereby re-Al particulates are produced from discarded aluminum beverage cans. This paper focuses on the intermetallic compound (IMC) formation study between the fabricated solder composite on Cu-substrate. Throughout this study, four different composition of Sn-0.7Cu/re-Al (0.0, 3.0, 3.5, 4.0 wt.%) were studied. X-ray diffraction (XRD) was used to analyze the IMCs phase formation between the interfaces. New IMC phase of Cu9Al4 was detected beside Cu6Sn5 and Cu3Sn in the composite solder samples. However, Sn-0.7Cu/3.0re-Al showed least formation of brittle IMCs compared to the monolithic solder.

The Effects of Electromigration to the Solder Joint Formation: A Comparison Between 99.3Sn-0.7Cu and 96.5Sn-3.0Ag-0.5Cu Lead Free Solder

Electromigration effects on the solder joint formation of 99.3Sn-0.7Cu and 96.5Sn-3.0Ag-0.5Cu lead-free solder with Cu electroplated Ni layer wire were investigated. The electromigration effects on the solder joints were studied after current density stressing at 1 x 103 A/cm2 in room temperature for 0 h, 120 h, and 240 h. The research work found that intermetallic compound (IMC) formation on the joint is increases for both solders with longer period of current stress applied. Higher IMC thickness growth in 99.3Sn-0.7Cu solder joint compared to 99.3Sn-0.7Cu is detected and both anode regions of the solder joints show higher IMC thickness growth compared to cathode region. Experimental results show 99.3Sn-0.7Cu solder joint is more prone to failure under current stress compared to 96.5Sn-3.0Ag-0.5Cu solder joint with thicker IMC which translates to higher brittleness.

Formation of Cu6Sn5/(Cu, Ni)6Sn5 Intermetallic Compounds between Cu3Sn-Rich Sn-Cu/Sn-Cu-Ni Powdered Alloys and Molten Sn by Transient Liquid Bonding

This paper presents the use of the transient liquid phase concept to grow the high temperature Cu6Sn5 intermetallic compound between Cu3Sn-rich powdered alloys and molten Sn. In this study, high temperature powdered alloys containing high fractions of Cu3Sn were fabricated from a chill-cast Sn-60 wt.%Cu alloy. A ternary alloy with composition of Sn-59 wt.%Cu-1 wt.%Ni was also prepared to investigate the effect of Ni. The reaction products were obtained at 250°C over a period of 30 minutes. The results provide new insight into the mechanism of the interfacial reaction between liquid Sn and solid Cu3Sn-rich alloy with and without Ni additions.

Hybrid Microwave-Assisted Rapid Sintering Process for Fabrication of Sn-0.7Cu+1.0wt.%Si3N4 Composite Solder

Hybrid microwave-assisted powder metallurgy sintering process is an emerging technology in synthesizing composite solder. In this study, a combination of microwave-energy heating and radiant heating from SiC crucible (so called hybrid heating) for the powder metallurgy sintering process for fabrication of Sn-0.7Cu+1.0wt.%Si3N4 composite solder was developed. The influence of different microwave power output with and without SiC crucible on the heating rate was measured. The effect of the increasing microwave exposure time on the microhardness values of Sn-0.7Cu+1.0wt.%Si3N4 composite solder sintered pellets were also measured to correlate the effect of heating behavior of the hybrid microwave-sintering and the present of the sintering mechanism within the green compact samples. It can be observed that the increasing of microwave power output has marginal effect to the heating rate of the setup. Higher heating rate using optimum power output (800 W) can be realized with the present of SiC crucible (susceptor material). The results revealed that the microhardness of the Sn-0.7Cu+1.0wt.%Si3N4 green compact decreases as microwave exposure time is increased. While, minimal microhardness value changes after 3 minutes (230 oC) using the 800 W of microwave exposure time.

Effects of Recycled-Aluminum Additions on the Mechanical Properties of Sn-0.7Cu/Cu-Substrate Lead-Free Solder Joints

Varying amount of recycled-Aluminum (0, 3.0, 3.5 and 4.0 wt.% re-Al) particulates produced from aluminium beverage cans were successfully reincorporated into Sn-0.7Cu base matrix solder material via powder metallurgy technique. This paper focuses on the mechanical properties aspect of the new solder when joint on Cu-substrate. The hardness of the composite solders sintered bulks was enhanced with the increasing re-Al additions. Moreover, the composite solders have shown enhancement of shear stress strength at the solder joints. Fracture surface of the failure samples were analyzed using scanning electron microscope (SEM) which have indicated all samples failed under ductile fracture mechanism. However, with the refining dimples formation shown on the fractograph, this report suggests the increasing re-Al reinforcement has optimized the solder joints ductility strength.

Thermal Properties of Sn-0.7Cu/re-Al Composite Lead-Free Solder

Composite approach in lead-free solder development was perceived as an expectation in finding new robust solder. Accordingly, Sn-0.7Cu/re-Al composite lead-free solder with varying amount of recycled-Aluminum (0, 3.0, 3.5 and 4.0 wt.% re-Al) particulates produced from aluminum beverage cans were successfully fabricated via powder metallurgy techniques in this study. This paper focuses on the thermal properties focusing on the melting temperature of the new developed Sn-0.7Cu/re-Al lead-free composite solder. The melting temperature (Tm) of the new solders was determined using differential scanning calorimetry (DSC). The melting temperature of the composite solders has showed comparable results with the monolithic solders of Sn-0.7Cu lead-free solder.