New assembling technique for BGA packages without thermal processes

A new assembling technique for flip-chip mounting without heating processes was developed. The proposed construction is an FR4 substrate with ring sha ped connectors. It is a typical flip-chip technology. The chip is placed, w ith its active part face-down, directly on to the connecting areas of the s ubstrate. The electrical connection is obtained through a mechanical contac t between the ring-shaped clips and the chip bumps. The main advantage of t he ring-clip-bump attachment technique is the possibility for multi-chip mo dules repairing without thermal processes. It is a lead-free assembling tec hnology involving only "conventional" processes. (C) 2001 Elsevier Science Ltd. All rights reserved.