In situ investigation of SnAgCu solder alloy microstructure

Effects of process conditions on reliability, microstructure evolution and failure modes of SnAgCu solder joints

In this study, microstructure evolution at intermetallic interfaces in SnAgCu solder joints of an area array component was investigated at various stages of a thermal cycling test. Failure modes of solder joints were analyzed to determine the effects of process conditions on crack propagation. Lead-free printed-circuit-board (PCB) assemblies were carried out using different foot print designs o...

Effect of PWB Plating on the Microstructure and Reliability of SnAgCu Solder Joints

This paper describes the interaction of the NEMI recommended lead-free solder for reflow assembly (Sn3.8Ag0.7Cu) with different commercial printed wiring board (PWB) platings. It also discusses the effects of plating type and manufacturer on the strength of the lead-free solder joints. PWBs from two different manufacturers with the same four types of plating were examined. The platings were org...

Measurement of deformations in SnAgCu solder interconnects under in situ thermal loading

Optical microscopy was used to discern the different grain orientations and grain boundaries on the polished cross-sections of neareutectic lead-free board-level SnAgCu (SAC) solder interconnects. Strain distributions with submicron accuracy of the deformations on the cross-sections of the solder interconnects were measured when the package was subjected to thermal loading from room temperature...

Reduced Impedance and Superconductivity of SnAgCu Solder Alloy at High Frequency

Skin effect of lead-free solder joints is investigated over a wide frequency band. Contrary to common believe that ‘effective impedance of solder alloys increases with frequency’, resistance tends to saturate when frequency reaches a critical value, 10 MHz for SAC solder alloys. Negative surface impedance growth rate is observed when employs square waveform AC current loading at high current de...

Microstructure-sensitive investigation of magnesium alloy fatigue