Development of conductive adhesive joining for surface-mounting electronics manufacturing

This paper presents the results of a study of process development for conductive adhesives as solder replacement. The main objective of the work was to investigate the potentials for using conventional surface-mounting equipment for component assembly with conductive adhesives. Two processes have been studied: one which uses both anisotropically and isotropically conductive adhesives and one which uses isotropically conductive adhesives only. The results from the work show that currently available surface-mounting machinery can be used for the conductive adhesive joining process. However, further work is needed to optimize the processing conditions. Transmission electron microscopy analysis of the adhesive joints after temperature cycling and humidity testing shows that oxide layer formation on metal surfaces can be one of the mechanisms which causes decrease in the electrical performance of the joint