A study of thermo-mechanical reliability of lead-free PTH solder joints

摘要

Purpose - The purpose of this paper is to consider PTH solder joint reliability, particularly on the PTH solder joints with partial hole-fill and without pin protrusion. Also, the impact of voiding on the solder joint reliability is discussed. Design/methodology/approach - Thermal cycling tests for samples of different hole-fill percentages and voiding were conducted, and cross-sections of the PTH solder joints were performed to evaluate the solder microstructure, intermetallic formation, via hole-fill, and the condition of the PTH metallization and PCB dielectric prior to thermal cycling and at different times during thermal cycling. Findings - Different failure mechanisms were observed for solder joints with and without pin protrusion. PTH components with pin protrusion had better through hole-fill and less voids than PTH components without pin protrusion. Originality/value - The paper discusses in detail the effect of hole-fill percentage and voiding on PTH solder joint reliability.