In recent years, with the reduction in the size of electronic devices and the increase in functionality, connection terminals in components (e.g., electronic components in liquid crystal products) have been miniaturized. Consequently, in the field of mounting electronics, as a conductive adhesive that can easily connect between such terminals, film-shaped adhesives are widely used. The conductive adhesive is used, for example, for connection between a printed circuit board or printed wiring board, such as a flexible printed wiring board or flexible printed circuit board (FPC) or a rigid printed wiring board or rigid printed circuit board (PWB or PCB) provided with connecting electrodes made of copper electrodes, and a circuit board or wiring board, such as a glass substrate provided with connecting electrodes, such as copper electrodes, and for connection between a printed circuit board or printed wiring board and electronic components, such as IC chips.
The conductive adhesive is an adhesive having anisotropic conductivity in which conductive particles are orientationally dispersed in an insulating resin composition. The conductive adhesive is interposed between adherends, and heat and pressure are applied thereto. When heat and pressure are applied, the resin in the adhesive flows and seals the surfaces of electrodes, and at the same time, bonding is performed such that some of conductive particles are grasped between electrodes which face each other to achieve electrical connection. Conventionally, gold plating is performed on the surface of a connecting electrode provided on a printed circuit board or the like in order to prevent oxidation and to ensure conductivity.