Site Redressing Techniques and Rework of Lead-Free Chip Scale Packages

The implementation of lead-free solder into an electronics assembly process necessitates the reassessment of the individual factors involved in component attachment and rework. A component assembly undergoes multiple thermal cycles during rework. With the use of lead-free solder, the assemblies are subjected to higher assembly and rework temperatures than those required for eutectic tin-lead assemblies. The rework of lead-free area array components involves the removal of defective component, preparation of the printed circuit board attachment pad (site redressing), solder paste replenishment or flux deposition, and component placement and reflow. This paper primarily focuses on the site redressing aspect of lead-free rework, followed by the development of rework processes for lead-free chip scale packages utilizing the knowledge gained in the site redressing studies.Copyright © 2003 by ASME