A Novel Running-in Method for Improving Life-Time of Bulk-Fabricated Silicon MEMS Devices

摘要

A running-in process is usually intentionally employed as an effective way to make friction pairs in macro-scale machinery more suitable for heavy load conditions. For silicon-based microelectromechanical systems (MEMS) with rubbing parts, however, even a short-time period of running-in under air or nitrogen environment can induce severe damage on rubbing surfaces, which prohibits any possibility of continuing operation. In this article, we demonstrate a new running-in process for MEMS devices, which can effectively reduce undesirable initial wear and thus generate an endurable bearing surface. The new running-in process consists of two steps of tapping treatment. A home-made microfriction test system has been developed to evaluate the effectiveness of this method. Through the tapping treatments, bearing spots on the rubbing sidewalls are restricted on several dominant locations, and the spreading of wear scar often observed in the test conditions without the tapping treatments is eliminated. After the running-in process, the life-time of the tested silicon MEMS devices has been extended in dry nitrogen test environment from 1 min to more than 1 h.