Home/Technical Glossary/ACF Bonding ACF Bonding The process of creating electrical conductive adhesive bonds between flexible and rigid circuit boards, glass panel displays and flex foils with very fine pitch (<30 micron) is known as ACF Bonding. The essential characteristics of this process are heating and cooling of the adhesive under pressure. Small, spherical particles are suspended in the adhesive, which can be in the form of foil, flex or paste. Before bonding, the particles are separated by an isolating matrix of adhesive. The parts to be joined are first brought together with the adhesive in between, and tacked (ACF laminating). Temperature, time and pressure are applied and cause plastic deformation of the adhesive and compression of the particles. The particles that are trapped between the conductors form a conductive interface between the pads on the two mating surfaces and conduct only in the Z axis. Subsequent cooling and full curing of the adhesive while still in the compressed condition stabilize the joint. For more information, take a look at our paper on Conductive Adhesive Bonding.