Fabrication of Meshed Pipes with a Diameter of 100 µm and a Structure Composed of Fine Slit Arrays

Abstract

Feasibility for fabricating meshed pipes was investigated using laser-scan lithography and electrolytic etching onto stainless-steel pipes with an outer diameter of 100 µm. Such meshed pipes will be useful as needles for filtering particles and granules mixed in liquids. The meshed pipes were designed by arraying 30 slits linearly in 8 lines by a circumferential angle pitch of 45º. Each 30-slit array was alternately shifted a half pitch in the axial direction from the neighbored slit-arrays. The target sizes of slits were 50 µm wide and 100 µm long, and the designed distance between slits in the axial direction was also 100 µm. Because the slit widths and lengths were enlarged by the undercut during the etching, slit patterns were delineated by reducing the sizes to 20 µm wide and 75 µm long. As a result, etched slit patterns with mean width and length of 18.5 µm and 74.9 µm, respectively, were obtained. When 6 pipes were etched, all the slits were successfully penetrated in two pipes. Although side walls of slits were inclined and contour edges became twofold caused by the undercut, it was judged that the new fabrication method of meshed pipes is feasible for developing various functional needles.