Low contact force probing on copper electrodes

A contact method between IC pads and probes at low contact force is a key to developing a probe card with over ten thousand probes and MEMS probe cards. In this paper, we have investigated the characteristics of new low-force contact methods on Cu electrodes in addition to Al electrodes. One method is to use an electric breakdown by applying voltage to the electrodes, and another one is to deoxidize the native oxide on the surface of the Cu electrode before probing. A conventional needle probe card of tungsten probes was used for the experiment. At a contact force of 1 mN, a contact resistance of less than 2 Ω was obtained by the deoxidization process, and 0.7 Ω was obtained by a combination of both the oxidation and electric breakdown by applying 10 V.