Silicon nanostencils with integrated support structures

We describe the fabrication of single crystal silicon membranes for stencil mask deposition. The membranes are created using standard microfabrication techniques combined with focussed ion beam milling to give structures with openings hundreds of micrometers to 50 nm in size. Deflection of the membrane structures under the deposition of highly stressed metals films is measured for vacuum deposited tantalum films, and used to estimate a film stress of 1.3 ± 0.1 GPa. In order to overcome these significant deflections, we have integrated simple stiffening structures into the membranes themselves which both preserve line of sight to the sample as well as provide a sufficiently large bending moment to resist vertical deflections which would otherwise cause noticeable feature broadening. Deposition of metallic nanowires on the surface shows good agreement with the calculated and measured deflections of the reinforced structures.