Abstract
In recent years, Anisotropic Conductive Films (ACFs) have been widely used in microelectronic packaging applications due to their potential advantages, which include low processing temperatures, high-resolution capabilities, and compatibility for nonsolderable materials. In this study, we investigated a novel, thermosonic ACF flip-chip bonding process using ultrasonic vibration. The thermosonic ACF flip-chip bonding was characterized in terms of adhesion strength and electrical property in comparison with conventional thermo-compression ACF bonding. ACF has a nickel particle with a 4-μm diameter, and its recommended thermo-compression bonding conditions were 453 K for bonding temperature and 10 s for bonding time. The investigated thermosonic flip-chip bonding conditions were 433 K and 453 K for bonding temperature and 0.5 s and 1 s for bonding time at each temperature, respectively. In addition, a cross-section of the ACF joint was observed using scanning electron microscopy. As a result, the developed thermosonic flip-chip bonding process showed good electrical and mechanical characteristics, as compared with those of the conventional thermo-compression bonding process. In the future, we expect that a thermosonic flip-chip bonding method with ACFs can be effectively applied to reduce the bonding temperature and time.
