Fabrication of microstructures with continuous surface profiles and very large sag heights by laser lithography

The fabrication of microstructures with continuous surface profiles and very large sag heights by a laser lithographic process on a commercially available laser lithography system is presented. The fabricated structures possess sag heights up to 60 µm with a pitch of 400 µm. Fabrication imperfections due to nonlinearities in the photoresist response and the isotropy of the development process have been compensated in the exposure data to minimize profile deviations. Therefore, an empirical process model is proposed based on experimentally determined development rates. The achievable accuracy of the data pre shape and exposure method as well as their limitations are discussed.