Thermal cycle/aging reliability of lead free 0201 assemblies

This paper presents the test results and comparative literature data on the influence of a few key manufacturing parameters and defects associated with the 0201 components using lead-free and tin-lead solder alloys. A large number of test vehicles assembled with 0201 components were subjected to isothermal aging at 150degC and thermal cycling in the range of -55degC to 100degC in order to establish their reliability. The shear tests were carried out at various aging intervals up to 500 hours to determine the effects of aging damage on the solder joint strength and this data are presented and compared to virgin assemblies. Weibull plots are given for reliability to establish solder joint aging behavior for the lead free assemblies compared to lead based solder as well as data correlation for various sets of data. Optical inspection photos taken during thermal cycling to establish damage progress, scanning electron microscopy (SEM) photos to reveal details of damage at 1500 cycles, and cross-sectional photomicrographs showing interconnect microstructural changes and intermetallic formation are also be presented