Lifetime Estimation of an ACF in Navigation (March 2010)

Recently, liquid crystal display (LCD) panels have become very important components for portable electronics. In the high-density interconnection material, anisotropic conductive films (ACFs) are used to connect the outer lead of the tape-automated bonding to the transparent indium tin oxide electrodes of the LCD panel. The ACF consists of an adhesive polymer matrix and randomly dispersed conductive balls. In this paper, we analyzed the failure mode/mechanism of ACF which were identified as conductive ball corrosion, delamination, cracking, and polymer expansion/swelling. In the accelerated life test, we selected primary stress factors, such as temperature and humidity. As time passed, an increase in connection resistance was observed. Low [50% relative humidity (RH)] and high (95% RH) conditions of average humidity show about 3-4 times difference in lifetime at the same average temperature of 30 ^°C. Hence, the humidity was shown to be more highly influential on the lifetime of the ACF, considering the driving patterns of regular consumers.