A review of lead-free solders for electronics applications

Review Article: Effect of alloying elements on properties and microstructures of SnAgCu solders

During soldering and service, intermetallic compounds (IMCs) have an important impact on the performance and reliability of electronic products. A thin and continuous intermetallic layer facilitates the formation of reliable solder joints and improves the creep and fatigue resistance of solder joints. However, if the IMCs overgrow, the coarse IMC becomes brittle and tends to crack under stress, leading to a decrease in solder joint reliability. Based on the latest developments in the field of lead-free solders at home and abroad, this paper comprehensively reviews the interfacial reaction between SnAgCu Pb-free solders and different substrates and the growth behavior of IMCs and clarifies the growth mechanism of interfacial IMCs. The effects of the modification measures of lead-free solder on the IMCs and reliability of SnAgCu/substrate interface are analyzed, which provide a theoretical basis for the development and application of new lead-free solder.

Interface reaction and intermetallic compound growth behavior of Sn-Ag-Cu lead-free solder joints on different substrates in electronic packaging

Effects of Ni modified MWCNTs on the microstructural evolution and shear strength of Sn-3.0Ag-0.5Cu composite solder joints

Influence of indium addition on characteristics of Sn-0.3Ag-0.7Cu solder alloy

Influence of Bi on microstructures evolution and mechanical properties in Sn–Ag–Cu lead-free solder

The solder materials used to make the solder joints for this study are: eutectic Sn-3Ag-0.5Cu solder; Sn-3Ag-0.5Cu-1Bi solder; and Sn-3Ag-0.5Cu-3Bi quaternary solder. In order to study the microstructure evolution and the IMC growth kinetics, the solder joints were aged isothermally in a resistance oven at 150/spl plusmn/5/spl deg/C with different periods of 0, 50, 100, 250, 500, and 1000 hours. The result show that: the morphology of IMC changes from scallop-like to planar in the aging process; the mean thickness of IMC layer solder joints is found to increase linearly with the square root of aging time, namely the growth of IMC is controlled by atom diffusion; the IMC growth rate decreased as Bi content increased. For the solders discussed above, the comparative IMC growth rate sequence from fast to slow is Sn-3Ag-0.5Cu > Sn-3Ag-0.5Cu-1Bi > Sn-3g-0.5Cu-3Bi.

The effect of Bi on the IMC growth in Sn-3Ag-0.5Cu solder interface during aging process

Three lead-free solder alloys, Sn-3Ag-0.5Cu, Sn-3Ag-0.5Cu-1Bi and Sn-3Ag-0.5Cu-3Bi, were used in the current experiments to investigated the microstructural evolution as well as the kinetics of intermetallic compound (IMC) layer growth. The experimental results indicated that the thickness of Cu6Sn5 intermetallic layer at the solder/Cu interface increases with aging temperature, while the growth rate of IMC in Sn-3Ag-0.5Cu-3Bi/Cu joints is slower than that in Sn-3Ag-0.5Cu-1Bi/Cu joints and Sn-Ag-Cu solder joints. The effect of Bi element is attributed to the accumulation of Bi near the joint and the enhancement of the activation energy by the addition of Bi

Lai Wang

Papers

Influence of Bi on microstructures evolution and mechanical properties in Sn–Ag–Cu lead-free solder

The effect of Bi on the IMC growth in Sn-3Ag-0.5Cu solder interface during aging process

Effect of Bi on the kinetics of intermetallics growth in Sn-3Ag-0.5Cu/Cu solder joint