ACP Mfg. tech. for rigid & flex board interconnection

Anisotropic Conductive Paste / Anisotropic Conductive Adhesive (ACP/ACA) type of Flex-on-Board (FOB) bonding method ensures good electricity between the flex electrode and organic substrate electrode for fine pitch ≤0.3mm design layout. ACP is an alternative material for connecting two circuits except Anisotropic Conductive Film (ACF), besides, it is industry acceptable lead free environment friendly material. The conductive particle passes electricity after heat press and the binder bonds the circuits and spacing to form solid interconnection. By conductive particle size selection, particle density and distribution control, a Z-axis electrically conductive pathway is formed. The adhesive does not conduct in the X-Y plane, thereby isolating the adjacent pathways. ACP have been used for Flip Chip gold bump bonding process in liquid crystal display(LCD) driver IC or Chip On Flex(COF) assembly in finger print sensor, while the application for rigid & flex board interconnection is relatively few. This paper describes the investigation of alternative low cost flex board bonding process which using Anisotropic Conductive Paste as an interconnection material on organic board such as PET.