Metal-assisted Chemical Etching (MaCE) of silicon is a new method to fabricate complex 1D, 2D and 3D silicon nanostructures. In this process, silicon etching is confined to a small region surrounding metal catalyst nanoparticles, thin films or shaped structures that travel in three dimensions during the etching process. This presentation will cover MaCE fundamentals including basic chemistry and how catalyst shape can be used to control the etching path to fabricate complex 3D silicon features including vertical and sloping channels, spirals, cycloids, "S-shaped" undercuts and more. This presentation will also detail the use of pinning structures to induce new bending and rotational modes to fabricate features with curved bottoms and with pre-defined rotation angles. Features ranging from 25 nm to 10 μm with aspect ratios greater than 10:1 and taper angles ~0.2° are easily achieved with this process.

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