Recent advances in anisotropic conductive films (ACFs) technology for green electronic assembly

Anisotropic Conductive films (ACFs) have been widely used in semiconductor and display applications for chip-on-glass (COG), flex-on-glass (FOG), flex-on-board (FOB), chip-on-flex (COF), chip-on-board (COB) interconnections due to their green and energy saving, fine-pitch capability, simple process, and cost effectiveness. There have been many technical innovations in terms of materials and processing technologies. In this presentation, novel energy saving vertical ultrasonic bonding ACF processing method and extremely low temperature curable ACFs will be introduced as recent ACF processing and materials innovation for energy saving solutions. Room temperature operating vertical Ultrasonic (U/S) bonding method was successfully invented as an alternative of conventional thermo-compression (T/C) bonding method. By utilizing spontaneous heat generation at the ACF layer by vertical U/S vibration, U/S bonding achieved significant energy saving, less than 3 seconds bonding time, reduced assembly thermal damage, good adhesion strength, good contact resistances, and reliability. In addition, low temperature bonding was also successfully conducted at 110°C for 15 seconds using newly invented photo active-ACFs. The PA-ACFs can save significant energy saving by reducing the bonding temperature down to 110°C.