Creating multi-layered structures with freestanding parts in SU-8

This paper reports on a new method to create multi-layered structures with freestanding parts in SU-8. Examples of such structures are beams partially resting on a post or microchannels. The method, based on high-absorption UV light with a wavelength of 313 nm in SU-8, is fast, uses only traditional micromachining equipment and requires very few processing steps. It is well suited for thin freestanding layers (<15 µm). Furthermore, a variant of a method that uses a built-in UV blocking layer to enable freestanding structures is described in detail. This method has a broader application range in terms of the thickness of the freestanding parts. Both methods are applied to the fabrication of optical fiber clamps.