Interference lithography for the synthesis of three-dimensional lattices in SU-8: Interrelation between porosity, an exposure dose and a grating period

• Three dimensional gratings with different periods were synthesized in SU-8.
• The best exposure time is different for making of gratings with different periods.
• To obtain porous gratings with smaller periods smaller exposure doses are requires.
• The suitable range of exposure doses is much narrower for smaller periods.

Three-dimensional gratings with different periods were synthesized in SU-8 photoresist through its triple exposure to two-wave interference pattern. Interrelation between porosity, an exposure dose and a grating period were investigated. It was found that decreasing porous grating periods require decreasing density of absorbed laser radiation. Moreover, decrease of grating periods leads to a narrow range of radiation dose that allows us to obtain porous structure.