Fig. 1

a Schematic illustration of the curing process of the hydrogen silsesquioxane (HSQ) resists from a cage-like structure to a network structure. b Fourier transform infrared (FTIR) spectra of as-cast and extreme ultraviolet (EUV)-exposed HSQ films for the range of Si–O–Si vibration. c Schematic illustration of scattering-type scanning near-field optical microscope (s-SNOM, beam splitter B/S, parabolic mirror P/M, reference mirror R/M). s-SNOM images of (d) cage-like structure (1125 cm⁻¹) and e network structure (1067 cm⁻¹) for 150 mJ/cm². The red color indicates higher infrared absorption. The scale bar is 3 μm