ИСТИНА

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 microstruc- tures’ 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, OrmoComp⃝R , and SZ2080TM 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 μm3 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 post- processing step for TPP-made structures made of IP-Dip, OrmoComp⃝R , and SZ2080TM . 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. In conclusion, we have analyzed the effect of pyrolysis on microstructures made of three photoresists for the temperatures of 450◦C and 690◦C. All photoresists have their advantages: pyrolyzed IP-Dip structures have the highest shrinkage ratio of 2.1 at the temperature of 450◦C, OrmoComp⃝R structures demonstrate best adhesion and survival rate after pyrolysis, while SZ2080TM structures are good at decoupling from the substrate’s surface and uniform shrinking. The results of the current work can be applied for developing pyrolysis as a standard post- processing technique for 3D microstructures created via TPP technology, which may be useful for overcoming the regular TPP restrictions. This work was supported by Russian Science Foundation (20-12-00371), the Ministry of Science and Higher Education of the Russian Federation (14.W03.31.0008) and MSU Quantum Technology Center. [1] M.I. Sharipova, T.G. Baluyan, K.A. Abrashitova, G.E. Kulagin, A.K. Petrov, A.S. Chizhov, T.B. Shatalova, D. Chubich, D.A.Kolymagin, A.G. Vitukhnovsky, V.O. Bessonov, and A.A. Fedyanin, “Effect of pyrolysis on microstructures made of various photoresists by two-photon polymerization: comparative study,” Opt. Mater. Express11, 371-384 (2021).