Restructuring in block copolymer thin films: In situ GISAXS investigations during solvent vapor annealing

Abstract

Block copolymer (BCP) thin films have been proposed for a number of nanotechnology applications, such as nanolithography and as nanotemplates, nanoporous membranes and sensors. Solvent vapor annealing (SVA) has emerged as a powerful technique for manipulating and controlling the structure of BCP thin films, e.g., by healing defects, by altering the orientation of the microdomains and by changing the morphology. Due to high time resolution and compatibility with SVA environments, grazing-incidence small-angle X-ray scattering (GISAXS) is an indispensable technique for studying the SVA process, providing information of the BCP thin film structure both laterally and along the film normal. Especially, state-of-the-art combined GISAXS/SVA setups at synchrotron sources have facilitated in situ and real-time studies of the SVA process with a time resolution of a few seconds, giving important insight into the pathways and mechanisms of SVA induced restructuring. We give a short introduction to the GISAXS method and review recent theoretical studies, experimental techniques such as sample preparation and in situ chambers together with SVA protocols, and we review and discuss experimental results. We conclude by giving an outlook on emerging developments of the in situ real-time GISAXS scattering technique in combination with new approaches to control BCP thin film structures using SVA.