Nanomechanical properties of SU8-photoresist thin films

SU8 photoresist thin films were fabricated using spin-coating with UV-photolithography technique. The nanomechanical tests were successfully conducted on a thin SU8 film on a Si-substrate to evaluate its elastic modulus and hardness. The tests were executed with great precision using a Bruker Hysitron Tribo Indenter equipped with a Berkovich indenter. The load (Pmax) varied between 70 μN and 500 μN, while the loading rate ranged from 5 to 20 μN/s. At an applied peak load of 100 µN and a loading rate of 10 µN/s, the elastic modulus and hardness obtained for SU8 pristine were found to be 6.50 ± 0.05 GPa and 454.6 ± 7.9 MPa respectively. It has been shown that elastic modulus and hardness increase with greater indentation depth.