Assembly and reliability of micro-scale solder interconnections for flip-chip MCMs

The essential features of a high-yield, cost-effective flip-chip multichip module (MCM) fabrication process using automated, whole wafer assembly are discussed. Tests demonstrating (1) superior cleanability of a new AT&T-YD flux as defined by wetting angle measurements and (2) the robust reflow realignment of flip-chip joints assembled using this flux are described and their results reported in detail. Finally, studies of the low-cycle fatigue behavior of flip-chip solder microjoints are presented. The results of this research point the way to designs and processes for the cost effective assembly of reliable flip-chip MCMs.<>