Effects of processing and storage conditions on the tribological behavior of monolayer lubricants for MEMS

COLL 160

Michael T. Dugger1, Joshua S. Wiehn1, and Diane E. Peebles2. (1) Microsystem Materials, Tribology and Technology, Sandia National Laboratories, P.O. Box 5800, MS0889, Albuquerque, NM 87185-0889, (2) Materials Characterization, Sandia National Laboratories, P. O. Box 5800, MS 0886, Albuquerque, NM 87185-0886
Organic monolayers are used on silicon surface micromachined (SMM) devices to improve yield and insure proper device operation. Changes in the chemistry of surfaces can have significant impact on the performance of SMM devices. These changes can result from mechanical stress, or interaction of the monolayer with other adsorbed species during post-fabrication processes or storage. Surface analysis, including x-ray photoelectron spectroscopy and scanning probe microscopy, has been used to investigate the chemistry and structure of films exposed to a variety of processing and storage conditions. Diagnostic microelectromechanical system (MEMS) devices have been used to investigate the effects of these exposure conditions on the friction behavior of chemisorbed monolayer lubricants. This paper will discuss correlations between surface chemistry, structure, adhesion, and static and dynamic friction behavior of adsorbed monolayers used in MEMS.