An ion milling pattern transfer technique for fabrication of three-dimensional micromechanical structures

We describe a useful method of transferring mask patterns over large distances using ion milling. This technique exploits the anisotropy of a collimated ion beam to etch the projection of a stencil mask pattern into a thin film. This method avoids the difficulties associated with photoresist processing on highly nonplanar substrates, and thus provides an alternative process avenue for the development of three-dimensional microstructures. We demonstrate this technique, in a process including wet anisotropic silicon etching, by fabricating arrays of high aspect ratio barbs which are intended for use in tissue fasteners in biomedical applications