Pyrolyzed microstructures made by two-photon polymerization: comparative study

Pyrolysis of microstructures made by two-photon lithography (TPP) allows to decrease the size of the objects and modify their chemical composition at the same time. While pyrolyzed TPP-made structures were previously studied, due to different experimental conditions – first of all, annealing temperature and duration, and microstructures’ shape – it’s impossible to compare the effect of pyrolysis on structures’ shrinkage and survival rate for the photoresists reported in the study. In this work we compare the effect of pyrolysis on solid objects sized by tenths of micrometers produced from three commercially available photoresists: IP-Dip, OrmoComp ® , and SZ2080 TM by TPP. We analyzed the structures’ size reduction, modification of chemical composition and adhesion to the silicon wafer substrate for the pyrolysis temperatures of 450°C and 690°C in the argon atmosphere [1] . Fig. 1 shows SEM images of microcube sructure with 34×40.2×50 µ m 3 dimensions made of IP-Dip before and after pyrolysis at 450°C. As a result of pyrolysis the microcube shrinks and deforms. However, with adjusted printing parameters and pyrolysis procedure, it is possible to achieve uniform shrinkage and apply pyrolysis as a repeatable postprocessing step for TPP-made structures made of IP-Dip, OrmoComp ® , and SZ2080 TM . Using thermogravimetric analysis, scanning electron microscopy, and X-ray energy dispersive analysis, we have detected pyrolysis-induced changes in microstructures’ size, chemical composition, survival rate and adhesion.