MEMS IC test probe utilizing fritting contacts

This paper describes how a micro-electro-mechanical system (MEMS) probe can be applied to IC testing, MEMS probe cards are requisite to tests of higher pad-density and smaller pad-pitch chips with high-speed signals above 1 GHz. Zn addition, if a microactuator is integrated into each probe, we can realize a novel probe card in which contacts can directly be switched on and off. The critical problem of the micromachined probe cards, however, is that each micromachined probe cannot generate or endure the force required to break the oxide on an Al pad surface mechanically. Furthermore, for the design of the switching probe card, the force necessary to disconnect the contact should be clarified. We experimentally found that the fritting makes it possible to get low resistance contact to Al pads without applying external forces. Using the Au bump, the contact resistance to Al pads was about 0.3 Ohm and the disconnection force was around 0.3 mN. In this report, we have carried out analytical calculation to estimate the performance of three different cantilever-type microactuator mechanism and to select and design the microactuator suitable for the switching probe card.