LCD driver IC assembly technologies and status

According to the difference of flex substrate, (reel tape), there are three assembly types for an LCD driver IC: COG, TCP and COF, respectively. TCP is the maturest of these types for stability of raw material supply and other specifications. TCP is the major assembly type of LCD driver IC in Taiwan's large TFT LCD panel house but due to its package structure and the raw material applied in this package, there is some limitation in fine pitch application of this package type. So, COF has the potential for compact and portable applications in the future. There are three kinds of assembly methods in COF: the first is ACF which uses an anisotropic conductive film to connect the copper lead of the tape and gold bump of the IC; the second is eutectic bonding by using the thermo-pressure to join the copper lead of the tape and gold bump of the IC; finally there is NCP which uses non-conductive paste to adhere the copper lead of the tape and gold bump of the IC. This paper briefly reviews the status of Taiwan's large TFT panel house, the internal driver IC design house, and the back-end assembly house. The different material properties of the raw material for the PI tape are also compared in the paper.