Super stretched solder interconnects for wafer level packaging

Abstract

A cost-effective wafer level packaging technique termed "stretch and break", based on stretching and detachment of solder interconnections, has been established. Excellent coplanarity, essential for wafer level test and burn-in, is inherent in the process. The technique allows the freedom to use solder materials of up to 400°C melting temperature for forming the interconnection. The shape of the interconnection can also be easily manipulated for optimum performance. The mechanical and thermal cycling reliabilities of the stretched solder interconnection has been found to be significantly better than those of conventional solder joints. © 2006 IEEE.