Alternative fine pitch solution of low cost and high throughput thermal compression bonding by using capillary underfill

Abstract

During last couple years, Flip Chip package form factor provide the ideal solution for high I/O and better electrical performance on handheld/networking market which included high frequency and high speed product characterization. With developing the fine pitch in chip attach process, there is a methodology called thermal compression bonding combining with capillary underfill (TCB+UF) technology, which is comibined between traditional mass reflow (MR) and thermal compression bonding with non-conductive paste (TCBNCP) [1][2]. Besides, process operation cylce time could be reduced since unit per hour throughput increase while applying underfill. A Flip Chip Ball Grid Array (FCBGA) with large die size, fine pitch Cu pillar bump, and the organic laminated substrate with bump on trace (BOT) was used as test vehicle for this study. Different flux transfer methodologies were also applied into DOE study to approach high throughput UPH and reduce process cycle time. The characterization analysis will utilize simulation methodology & typical reliability testing (Temperature Cycle Test, unbias HAST and High Temperature Storage Test) condition as a quality judgment metrology for TCB+UF process evaluation. Finally, this paper will find out the suitable TCB+UF of key process feasibility data for future fine pitch product application.