Probing Self-Assembly of Cylindrical Morphology Block Copolymer Using in Situ and ex Situ Grazing Incidence Small-Angle X-ray Scattering: The Attractive Case of Graphoepitaxy

The self-assembly of polystyrene-block-poly(methyl methacrylate) (PS-b-PMMA) copolymer (BCP) films, leading to hexagonal arrays of perpendicular PMMA cylinders in a PS matrix, and its ordering kinetics were investigated using ex situ and in situ grazing incidence small-angle X-ray scattering (GISAXS). The ex situ measurements have provided accurate information about the structural changes in self-assembled BCP films with multiple processing parameters (PMMA removal process, film thickness, annealing treatment). Such structural information proves essential since BCP films are envisioned as template materials for density multiplication in nanolithography. Moreover, the temperature-dependent GISAXS measurements indicate that phase-separation starts around 140 °C and annealing up to 240 °C is required to form homogeneous self-assembled films within the short baking times required by industry. Furthermore, the guiding effect of an hydrogen silsesquioxane (HSQ) line grating commensurable with the polymer period...