Thin Film Programmable Interconnect Arrays

A new low cost material is presented for the realization of thin film programmable interconnect arrays for selective switching of chip to substrate interconnects from a high impedance state to a low impedance state. The programmable interconnect arrays are realized using a tri-level graphite-filled polyimide system as an interlayer material between metallic electrodes. The interconnects are switched from a high impedance to a low impedance state using an activation current to heat the material between the electrodes. This current causes an irreversible change of material resistivity which persists even after the current is removed. The graphite loading of the individual layers is varied in order to obtain the optimal interconnect characteristics. The characteristics of interest at this time are the dc levels of the interconnect initial resistance and the final resistance as well as the magnitude of the change in resistance between the initial and final states. Results of various layer combinations including 5/30/30, 0/18/0 and 3/3/3 wt% graphite are presented.