Synchronous scan-projection lithography on overall circumference of fine pipes with a diameter of 2 mm

Abstract

The scan-projection exposure of small-diameter pipe surfaces was investigated using a newly developed prototype exposure system. It is necessary to secure a very large depth of focus for printing thick resist patterns on round pipe surfaces with a roughness larger than that of semiconductor wafers. For this reason, a camera lens with a low numerical aperture of 0.089 was used as a projection lens, and the momentary exposure area was limited by a narrow slit with a width of 800 µm. Thus, patterns on a flat reticle were replicated on a pipe surface by linearly moving the reticle and rotating the pipe synchronously. By using a reticle with inclined line-and-space patterns, helical patterns with a width of 30 µm were successfully replicated on stainless-steel pipes with an outer diameter of 2 mm and coated with a 10-µm-thick negative resist. The patterns replicated at the start and stop edges were smoothly stitched seamlessly.

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

“…Stent-like patterns were replicated on a pipe surface coated with a resist using a handmade exposure system developed in the past research [12,13]. The system is shown in Fig.…”

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.…”