Structural and Micromechanical Assessment of Electrochemically Grown Metal Layers for Si Magnetic Microactuators

Abstract

The electrochemical deposition of Cu metal layers for Si based microactuator devices is investigated as a function of the substrate structure. For the direct deposition of Cu onto Si, a two step process involving pre-deposition of an intermediate layer under alkaline conditions has been developed. This has allowed the optimization of the process in terms of film adherence and thickness. On the other hand, for processes involving the use of dielectric sacrificial layers, the electrochemical growth of the Cu film requires a metallic seed layer. In this case, the growth of Cu onto Au coated surfaces has been investigated, and the process has been applied to the development of test microactuator structures based on the integration of Cu coils onto Si micromachined devices. The fabrication of these devices demonstrates the full compatibility of Electrochemical processes with Si standard micromachining technologies.