Anisotropic conductive film (ACF) bonding is commonly applied to automotive systems. It is far better than zero insertion force (ZIF) connectors, board-to-board (BTB) connectors, or soldering. In cars, there is less space for connections and ACF offers a reliable and cost-effective way of making electrical connections.
For many years manufacturers have been using ACF to make electrical conductive adhesive bonds between flexible and rigid circuit boards, glass panel displays, and flex foils. The process heats and cools a paste that contains conductive particles. A little pressure is used to get accurate and strong bonds. After being widely used for fine pitch connections, it is now being used for a large variety of auto-safety and driver assistance systems. ACF is also used in sensor applications, advanced communication systems, and self-directed driving systems.
The electrically conductive adhesive bonds create interconnections between flex and rigid circuit boards. This bonding technique allows for smaller models and sleek looking cell phones. The slim LCD TVs we use at home are also made using electrically conductive adhesive bonds. These days, no printed circuit board is complete without the use of ACF bonding. The material is used for adhesion, electrical link, and padding of the nearby terminal.
The ACF contains tiny spherical particles which when heated in a compressed state can make the electrical connection between two parts. There is no need for wiring which makes it a very cost-effective joining solution. The adhesive has a conductive material which can be either foil, flex, or paste. Particle density and thickness is ensured when conductive particles are scattered in an even manner.
Before ACF bonding, there is ACF lamination. The adhesive isolates the particles and when two parts to be joined are tacked together it is called as ACF lamination. A thermode is then used to heat up while pressing together the circuit boards with the adhesive. The adhesive flows and traps the conductive particles thus creating an electrical connection. To get a strong joint the spot to be bonded is then cooled. The amount of filler content is low thus eliminating the risk of short circuits. Conductive particles can be graphite, gold, or gold-plated plastic. All these have their advantages and disadvantages.