Fabrication of Stent-Like Mesh Structures Using Synchronized Scan Rotation Lithography and Wet Etching

Stent-like complicated cylindrical structures were made with pipes of stainless-steel SUS 304 using new lithography and wet chemical etching. In the new lithography, patterns on a flat reticle were printed on a pipe coated with a resist film by synchronously scanning the reticle linearly and rotating the pipe around the axis, and limiting the momentary exposure area on the top ridge of the pipe by placing an oblong slit on the reticle in parallel to the pipe axis. The patterned pipe was wetly etched in an aqueous solution of ferric chloride using the resist patterns as etching masks. Because the etching was progressed equally in all the directions from the resist pattern edges, masked parts under the resist patterns were also gradually etched from the pattern edges and undercut during the pipe was penetrated through the wall. Caused by the undercut, obtained mesh widths became narrower than the resist pattern widths. However, a stent-like mesh structure with widths of 108±12.4 (3σ) µm was decently fabricated by appropriately controlling the resist pattern width and the etching time. To attain higher accuracy in the future, cross section profiles of the mesh and relationship between resist pattern widths and mesh widths were discussed in detail.