Characterizing the intermetallic formed during ball attach process

Abstract

Continuously miniaturization of electronic components using PCB's technology for the manufacturing of SDRAM's uses a solder ball attach process, producing a joint which robustness and electrical response are crucial factors to success. At present, near-eutectic Sn-Ag-Cu alloys are the leading candidates for Pb-free solders. According to Chun et al., the rapid formation of Cu-Sn intermetallic compounds at the interface affects the reliability of this solder joint and represents a major concern. In this study we characterize the interface of an attachment between the copper layer conductors of a memory and a solder ball which allows further bonding to printed circuit modules, see figure 1.a.