CRITICAL-REVIEW - ADHESION IN SURFACE MICROMECHANICAL STRUCTURES

We present a review on the state of knowledge of surface phenomena beh ind adhesion in surface micromechanical structures. After introducing the problem of release-related and in-use adhesion, a theoretical fram ework for understanding the various surface forces that cause strong a dhesion of micromechanical structures is presented. Various approaches are described for reducing the work of adhesion. These include surfac e roughening and chemical modification of polycrystalline silicon surf aces. The constraints that fabrication processes such as release, dryi ng, assembly, and packaging place on surface treatments are described in general. Finally, we briefly outline some of the important scientif ic and technological issues in adhesion and friction phenomena in micr omechanical structures that remain to be clarified. (C) 1997 American Vacuum Society.