Contact geometry effects on friciton in MEMS probe arrays

Abstract

This paper examines the friction and wear properties between a laterally unconstrained slider and an array of AFM-like probe tips. Specifically, it focuses on how variations in the actual number of contacts and contact geometry (varied by tip wear) influence the friction forces. Results show that the steady state friction coefficient increases dramatically as the number of contact points increases. Additionally, initial variations in the friction forces due to rapid tip wear become steady after sliding distances greater than 1 mm. These results combined with SEM images of the tip wear imply that the wear rate becomes minimal as the contact pressure is reduced to approximately 20 MPa.