Fusible I/O interconnection systems and methods for flip-chip packaging involving substrate-mounted studbumps

摘要

Methods are disclosed for electrically connecting I/O bond-pads on a chip to corresponding I/O bond-pads on a substrate. In an exemplary method a respective stud-bump is formed on each I/O bond-pad on the substrate. The stud-bumps can be made of a fusible material, or a layer of fusible material can be formed on each I/O bond-pad on the chip. The chip is flipped and placed on the stud-bumps such that the I/O bond-pads on the chip are registered with the corresponding stud-bumps on the substrate. At each stud-bump, the fusible material is caused to fuse with and electrically connect the respective stud-bump to the respective I/O bond-pad on the chip. The method can include forming under-bump metallization (UBM) on each of the I/O bond-pads on the chip before placing the chip on the stud-bumps. The resulting structures provide robust I/O connections and can be fabricated using fewer process steps and using process steps that are compatible with other processes in wafer-fabrication and chip-assembly facilities.