Robert Albert Boie

Integration and packaging of MEMS relays

Micro machined relays provide switching solutions that are advantageous over existing technology in many aspects of device performance. In order to fully benefit from the MEMS solution n switching, however, a general integration strategy to various integrated circuit electronics needs to be developed. We describe the design and test of such an integration scheme utilizing flip-chip bonding of MEMS relays onto another substrate carrying the remainder of the circuitry. Individual devices consists of cantilever-like mechanical structure carrying a mobile electrode that is electrostatically actuated. The presence of a second substrate in the flip-chip bonded geometry provides the unique possibility of placing electrostatic actuators on both sides of the cantilever, thereby allowing active turn- on and turn-off of the relay device. The fabricated relays show switching time as short as 10 microsecond(s) , actuation voltages as low as 25V, on-state DC resistance as low as 2 (Omega) and open-state DC resistance as large as 1013 (Omega) . The device is assembled and packaged using a single-step flip- chip bonding process. Upon flip-chip bonding, the MEMS devices are completely enclosed in a small cavity between the two substrates that is sealed by a ring-type solder seal. Such techniques provide the opportunity for the integrated chip to be further packaged using conventional cost-effective packaging techniques.