New Flip-Chip Bonding Technology NSD (Non-Conductive Film Stud-Bump Direct Interconnection) Method Using Resin Encapsulation Sheet ―Examination of Material Physical Properties and Joint Reliability by FEM ―

摘要

We developed a new flip-chip process called the NSD (Non-Conductive Film Stud-Bump Direct Interconnection) method. First, a resin encapsulation sheet is attached to the substrate by heat compression. Stud-bumps are formed on an IC chip by means of conventional wire-bonding technology. The chip is then attached to the substrate. Finally, the encapsulation sheet is heated and compressed using a heating tool, during which the stud-bumps contact the electrodes on the substrate to form electrical interconnections that follow the substrate warp. When the encapsulation sheet cools, a compression force is generated between the IC chip and substrate, thus maintaining the interconnections. Highly reliable interconnections were obtained by optimizing the encapsulation sheet properties using the Finite Element Method (FEM). We report on the relationship between the encapsulation sheet properties and the reliability when bare ICs are attached using the NSD method onto an ALIVH~(TM) substrate, which utilizes unique epoxy-impregnated aramid non-woven cloth.