All-copper contacting technology for film-vs-film electric connection using cool plasma sintering

Tiling expansion enables the fabrication of large-area electronics at a much lower equipment cost than manufacturing a large-area device in one piece. Thin connection technology is expected to play a key role there. Contact resistances of the existing film-type flexible connectors are, however, rather high, compared with the conventional connectors or soldering. To realize a lower contact resistance, we inserted copper ink between two mating electrodes on a pair of films and sintered it by cool plasma sintering, a technology recently developed by our group. We achieved a contact resistance of about 20 mΩ, which is sufficiently low and compatible with the most demanding applications.