Lead-free soldering: Materials science and solder joint reliability

Mechanical Properties and Solder Joint Reliability of Low-Melting Sn-Bi-Cu Lead Free Solder Alloy

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...

Solder Creep-Fatigue Model Parameters for SAC & SnAg Lead-Free Solder Joint Reliability Estimation

For many of the Pb-free solders required under the European RoHS directive, there is now sufficient information, primarily in the form of the results of accelerated thermal cycling of various levels of severity, to develop acceleration models for the creep-fatigue of these solders. In this paper the parameters for the SAC405/305, SAC205, SAC105 and SnAg to replace the parameters for eutectic Sn...

Lead-Free Soldering for Space Applications Lead-Free Solder Body of Knowledge

Lead-free Solder Joint Quality Investigation

New Pb-free materials ask thorough verification because their properties as wetting, solderability and mechanical properties are different from these SnPb. In this paper are presented some new facts from creep and stress relaxation investigation including new arrangement for measurement. Results from creep, stress, shear and bend testing are presented for three types of solder (Sn/3.5Ag, Sn/3.8...

Reliability of Lead-Free LGAs and BGAs: Effects of Solder Joint Size, Cyclic Strain and Microstructure

An accelerated thermal cycle experiment comparing similarly constructed area array devices representing Land Grid Array (LGA) and Ball Grid Array (BGA) technology with 0.254, 0.30, and 0.40mm diameter SAC305 solder balls was performed. The devices were subjected to three thermal cycle conditions in order to promote 2nd level solder fatigue. Failure data was compared using Weibull analyses. The ...