The effect of bonding force on the electrical performance and reliability of NCA joints processed at a lowered temperature

The effect of the bonding force during flip chip-on-flex (FCOF) assembly on the electrical performance of the nonconductive adhesive (NCA) interconnects was investigated in this study, under the precondition of a reduced processing temperature in order to minimize thermally-induced damage to the low-cost flexible substrates. Pressure cooker tests (PCT) were performed to assess the reliability performance of the adhesive joints in high temperature and high humidity conditions. The assembly process was modified and the processing temperature and the bonding force were adjusted according to the experimental results to enable the use of low cost substrates, such as poly(ethylene terephthalate) (PET) materials in smart card fabrication.