Electrical characteristics of a new class of conductive adhesive

Conventional conductive adhesives are composed of micro-sized filler metal and polymer matrix. Currently. the conductivity of conventional conductive adhesives is generated by small contact points formed among the particles during the curing process and by the tunneling effect. Therefore, conventional conductive adhesives generally exhibit higher electrical resistance than metal solder materials. In this study, a new class of conductive adhesive, composed of nano-particles, and micro-particles in epoxy, was developed to improve electrical conductivity. This study used four conventional conductive adhesives (CCA1 to 4) and three hybrid conductive adhesives (HCA1 to 3). Scanning electron microscopy (SEM) observation was used to investigate the configuration of nano-particles and micro-particles. The electrical resistance of HCA1 to 3 was investigated and compared to CCA1 to 4 using a four-point probe method, When 2 mass% of nano-particle content was added to the micro-particle (HCA1). the electrical resistance decreased compared to CCA3, At 4 mass% of nano-particle content (HCA2), the electrical resistance value was similar to CCA3, However,at 8 mass% of nano-particle content (HCA3), the electrical resistance continued to increase, and exceeded that of CCA3.