Advanced interconnect materials for ink-jet printing by low temperature sintering

In this study, we reported the development of a novel highly electrically conductive adhesive (ECA) that can be used in ink-jet printing and have the function of adhesive by a single step of low temperature sintering/curing. With the introduction of silver nanoparticles into the formulation, the electrical resistivity of the resulting ECAs is about 10^-5 ohm-cm after sintering at 180degC or using a typical lead-free reflow profile (sintering/curing time: several minutes), which is compatible with industrial processis and favorable for the industrial applications. As is known, the strong adhesion of epoxy may enable the resulting ECA to be printed on various kinds of substrates, especially on flexible organic substrates, which is very promising for microelectronic applications. Moreover, the effects of time, temperature and the acid on the electrical resistivity of the ECA have been investigated, providing an in-depth understanding of the enhanced electrical properties. Finally, the contact resistance of the ECA on Cu surface can be stabilized for more than 1500 hrs. Thus the newly developed ECA can be ink-jettable, be compatible with industrial processes, has very low electrical resistivity by low temperature sintering/curing and could provide a strong adhesion to various substrates. The superior material properties of the formulated ECA combined with ink-jet printing technology will be very promising for a wide range of industrial applications in electronic industry.