The influence of alloy composition of lowmelting Sn-Bi-Cu lead-free solder alloys on mechanical properties and solder joint reliabilities were investigated. The mechanically optimum alloy composition is Sn-40Bi-0.1Cu (mass%). The addition of 40mass%Bi improves the ductility and restrains the fillet-lifting, which are problems of lead-free solders with Bi. The addition of copper improves both th...

To give a proper and accurate estimation of the fatigue life of ball grid array (BGA) solder joints, a mechanical fatigue test method under mixed-mode loading is proposed. Experiments were conducted with 63Sn/37Pb and Sn/3.5Ag/0.75Cu solder joints in room temperature. The mechanical low cycle fatigue tests were performed under several loading angles. The loading angle is controlled by several g...

The joining of lead-free Sn-3.0Ag-0.5Cu (SAC305) solder alloy to metal substrate with the addition of a porous Cu interlayer was investigated. Two types of porous Cu interlayers, namely 15 ppi—pore per inch (P15) and 25 ppi (P25) were sandwiched in between SAC305/Cu substrate. The soldering process was carried out at soldering time of 60, 180, and 300 s at three temperature levels of 267, 287, ...

Currently, the portable electronic products trend to high speed, light weight, miniaturization and multifunctionality. In that field, solder joint reliability in term of both drop impact and thermal cycling loading conditions is a great concern for portable electronic products. The transition to lead-free solder happened to coincide with a dramatic increase in portable electronic products. Sn–A...

Three types of inexpensive Pb-free solder joints, namely Zn-based and Bi-based solders, and a CuSn alloy were studied for application to the high-temperature operation of wide band-gap power semiconductor devices using GaN or SiC. Zn– Al solder sheets, whose melting point is 380°C were prepared, and then surface oxides were removed by RF plasma etching. Subsequently, Cu thin films were deposite...

The finite element procedure with the unified disturbed state modeling concept presented in Part I, Basaran et al. (1998), is verified here with respect to laboratory test results for Pb40/Sn60 eutectic solder alloy. This solder alloy is a commonly used interconnection material for surface mount technology packages. It is demonstrated that the proposed procedure provides highly satisfactory cor...

Au (0.05 μm) 69.4 μm Electromigration may affect the reliability of flip-chip solder joints. Eutectic solder is a two-phase alloy, so its electromigration behavior is different from that in aluminum or copper interconnects. In addition, a flipchip solder joint has a built-in currentcrowding configuration to enhance electromigration failure. To better understand electromigration in SnPb and lead...

Sn-Ag-Cu (SAC) alloy is currently recognized as the standard lead-free solder alloy for packaging of interconnects in the electronics industry, and highAg-content SAC alloys are the most popular choice. However, this choice has been encumbered by the fragility of the solder joints that has been observed in drop testing as well as the high cost of the Ag itself. Therefore, low-Ag-content SAC all...

Low temperature, Sn-based Pb-free solders were developed by making alloy additions to the starting material, 96.5Sn-3.5Ag (mass%). The melting behavior was determined using Differential Scanning Calorimetry (DSC). The solder microstructure was evaluated by optical microscopy and electron probe microanalysis (EPMA). Shear strength measurements, hardness tests, intermetallic compound (IMC) layer ...