|
Recently, it is required to develop a method for fabricating cylindrical micro-components in the field of measurement
and medical engineering. Here, electrolytic etching of fine stainless-steel pipes patterned by laser-scan lithography was
researched. The pipe diameter was 100 μm. At first, a pipe coated with 3-7 μm thick positive resist (tok, PMER P
LA-900) was exposed to a violet laser beam with a wavelength of 408 nm (Neoark,TC20-4030-45). The laser beam was
reshaped in a circle by placing a pinhole, and irradiated on the pipe by reducing the size in 1/20 using a reduction
projection optics. Linearly arrayed 22 slit patterns with a width of 25 μm and a length of 175 μm were delineated in
every 90-degree circumferential direction. That is, 88 slits in total were delineated at an exposure speed of 110 μm/s. In
the axial direction, patterns were delineated at intervals of 90 μm. Following the pattern delineation, the pipe masked by
the resist patterns was electrolytically etched. The pipe was used as an anode and an aluminum cylinder was set as a
cathode around the pipe. As the electrolyte, aqueous solution of NaCl and NH4Cl was used. After etching the pipe, the
resist was removed by ultrasonic cleaning in acetone. Although feasibility for fabricating multi-slit pipes was
demonstrated, sizes of the etched slits were enlarged being caused by the undercut, and the shapes were partially
deformed, and all the pipes were snapped at the chuck side.
|
