Interface Tailoring to Enhance Thin Film Adhesion — A Review

Abstract

Although thin film applications find increasingly important application in new technologies, the basic investigation of their adhesion mechanisms has, until recently, been greatly neglected. Although empirically developed adhesion processes have served us well, it seems likely that a deeper understanding of the critical physical origins of adhesion may offer advances in the ability to join new systems strongly and to design more reliable processing technologies. In the recent surge of research interest in this area, it has become clear that adhesion results from a variety of factors, ranging from interface chemistry to the elastic properties of the interface materials. Recognizing the role of these factors, it becomes desirable to use new techniques to tailor the interface properties for maximum adhesion. This can be achieved in many ways, by suitably chosen treatments before, during or after deposition of the film. Several such methods depend on the interaction of ion beams with interface materials, in order to adjust the interface structure on an atomic scale. In this discussion, we shall review some of the phenomena observed for thin films deposited on solid substrates. We shall then discuss the opportunities to tailor the interface properties in order to enable or improve adhesion performance.