Rotational UV lithography device for cylindrical substrate exposure

Optical photolithograhy is a well developed technique, which is normally restricted to planar substrates used in microelectronics or microelectromechanical system fabrication. For other applications--e.g., patterning of stents--photolithography would be an attractive alternative to techniques such as laser structuring provided that the planar technique could be adapted to cylindrical geometries. This study presents the development of a three-dimensional UV photolithography exposure method using a synchronizing movement between a planar Cr mask and a circular substrate. This technique was successfully applied to tubes with outer diameters between 1 and 5 mm. A lateral resolution for a 5 microm feature size of 4.8 microm was achieved, which is close to the resolution of 4.6 microm for similar planar films.