Merged-mask micro-machining process

The present invention provides merged-mask processes for fabricating micromachined devices in general and mirrored assemblies for use in optical scanning devices in particular. A method of fabricating a three dimensional structure, comprising, providing a substrate, applying a layer of a first masking material onto the substrate, applying a layer of a second masking material onto the layer of the first masking material, patterning the layer of the second masking material, applying a layer of a third masking material onto the portions not covered by the patterned layer of the second masking material, the layer of the third masking material is at least as thick as the combined thickness of the layers of the first and second masking materials, patterning the layers of the first and third masking materials, etching the exposed portions of the substrate, etching the exposed portions of the layers of the first and third masking materials and etching the exposed portions of the substrate.