A real Chip Size Package (CSP) of the face down type using ACF (Anisotropic Conductive Film) and PI substrate (Tape for Tape Automated Bonding), called “T-CSP (Tape-CSP) ”, has been developed. The Au-ball bumps that were formed on the LSI's Al electrodes were connected to Cu patterns on PI substrate using ACF. Solder balls were mounted into the through holes of PI substrate, after that, it's treated through each reflow process, cleaning, marking, and cutting. This T-CSP has many advantages ; the structure and the process are very simple. It can be applied an reel to reel line. So its cost also is lower than ordinary mold type ones. Furthermore, since the Robust design was performed and a high performance ACF was developed, T-CSP has very high reliability as LSI packages, that is, it clears both JEDEC level 1 tests, and also 1500 cycles of BLT (Board Level Thermal-Cycle Test) from-25 to + 125 degree C.
