A novel fabrication technology for smooth 3D inclined polymer microstructures with adjustable angles

Abstract

A novel technique for the fabrication of three-dimensional microstructures with inclined planes of adjustable angles is proposed. Angles of inclination from 19 to 90 degrees could be easily achieved by an inclined UV exposure on SU8 resist with thickness from 100 to 1000 μm. Glycerol is employed as an index matching material during exposure to compensate the refractive index difference between air and SU8, thus extends the possible inclined angles from 54° (in air) down to 19° (in glycerol). 45° inclined mirrors can be easily fabricated by this method. To eliminate reflection induced patterns, CK-6020L resist is employed as an antireflection coating layer and mesa structures with surface of optical quality has also been successfully demonstrated by 5 times exposures in corresponding directions.