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

Abstract

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.

Distortions of parabolic mirror optics for stereophonic lithography and prospects of compensations

“…On the other hand, as a new application of lithography, the replication of rough and large patterns on curved surfaces such as cylindrical pipes and shafts is required and has been researched. Such patterning technologies are expected to be applied to fabrications of cylindrical components such as micro-turbines and micro-screws, 1) axial encoders, 2) micro-coils, 3,4) micro axial pumps, 5) bearing grooves, 6) surface texturing, 7) high-density spirals for improving heat conductivity, 8) medical stents, 9) meshed needles, 10) and others. Recently, in addition to such cylindrically curved surfaces, patterning on arbitrarily but gently curved surfaces has begun to be required to make health monitoring devices and accessories such as wiring and electrode parts to attach them to curved body surfaces.…”

Feasibility of stereophonic projection lithography applying a parabolic magic mirror system

“…[11][12][13] The authors have been developing various lithography tools for printing or delineating 10-50 μm patterns on cylindrical surfaces of pipes or shafts with diameters between 100 μm and 6 mm also. [14][15][16][17][18] In addition, exposure tools for forming patterns on inner surfaces of pipes or concave surfaces are also developed. 19,20) However, it was difficult to print patterns on arbitrarily curved surfaces such as spherical, barrel-like, paddle-like, waved, and freely warped ones.…”