Contact Resistance Evolution of Au-Au Micro-Contacts with Encapsulated Ag Colloids

This paper reports the contact resistance evolution results of thin film, sputtered gold with encapsulated Ag colloids, micro-contacts dynamically tested up to 3kHz. The upper contact support structure consists of a sputtered gold surface micromachined, fixed-fixed beam designed with sufficient restoring force to overcome adhesion. The hemisphere-upper and planar-lower contacts are mated with a calibrated, external load resulting in approximately 100μN´s of contact force. Contact resistance is measured, in-situ, using a cross-bar configuration and the entire apparatus is isolated from external vibration and housed in an enclosure to minimize contamination due to ambient environment. Additionally, contact cycling and data collection are automated using a computer and LabVIEW. The results showed that Au-Au micro-contact had a final resistance of 14Ωs after 10 million cycles and 81Ωs after 8 million cycles with Au-Ag micro-contacts.