Simulations, analysis and characterization of the development profiles for the thick SU-8 UV lithography process

A two-dimensional (2D) simulation system is developed for the ultraviolet (UV) lithography process of thick SU-8. A series of simulations and experiments have been conducted to verify the simulation system and to study the effects of different lithography parameters on the line width deviations and sidewall profiles of the SU-8 microstructures. All studies are carried out on SU-8 2075 layers under UV source with 365nm (2.6mW/cm²) wavelength. The final development profiles of the SU-8 for air gaps with and without index matching materials, for various line/space and for different development time have been investigated and analyzed by combining simulation and experimental results. The results confirm the validity of the proposed simulation system and this is useful to accurately design and control the dimensions of some SU-8 microstructures.