Self-assembling block copolymers generate nanostructured patterns which are useful for a wide range of applications. In this paper we demonstrate the capability to control the morphology of the self-assembling process of PS-b-PMMA diblock copolymer thin films on unpatterned surfaces by means of fast thermal treatment performed in a rapid thermal processing machine. The methodology involves the use of radiation sources in order to rapidly drive the polymeric film above the glass transition temperature. Highly ordered patterns were obtained for perpendicular-oriented cylindrical and lamellar PS-b-PMMA block copolymers in less than 60 s. This approach offers the unprecedented opportunity to investigate in detail the kinetics of the block copolymer self-assembly during the early stages of the process, providing a much deeper understanding of the chemical and physical phenomena governing these processes.

The pattern coarsening dynamics in symmetric polystyrene-b-polymethylmethacrylate (PS-b-PMMA) block copolymer thin films under conventional thermal treatments is extremely slow, resulting in limited correlation length values even after prolonged annealing at relatively high temperatures. This study describes the kinetics of symmetric block copolymer microphase separation when subjected to a thermal treatment based on the use of a Rapid Thermal Processing (RTP) system. The proposed methodology allows self-organization of symmetric PS-b-PMMA thin films in few seconds, taking advantage of the amount of solvent naturally trapped within the film during the spinning process. Distinct and self-registered morphologies, coexisting along the sample thickness, are obtained in symmetric PS-b-PMMA samples, with periodic lamellae laying over a hexagonal pattern of PMMA cylinders embedded in the PS matrix and perpendicularly oriented with respect to the substrate. The ordering dynamics and morphological evolution of the coexisting dual structures are delineated and the intimate mechanism of the self-assembly and coarsening processes is discussed and elucidated.

Tailoring surface energies is the key factor to control the orientation of nanoscopic structures in thin block copolymer (BCP) films. In the general frame of the “grafting to” approach, this paper reports on the use of Rapid Thermal Processing (RTP) technology to perform flash grafting reactions of a hydroxyl terminated poly(styrene-r-methylmethacrylate) random copolymer to the activated silicon wafer surface. The perpendicular orientation of the cylindrical morphology of an asymmetric PS-b-PMMA block copolymer is achieved when the thickness of the random copolymer layer is higher than 6.0 nm. The grafting time to achieve this thickness reduces from about 750 s, when the RTP grafting process is performed at 230 °C, to 15 s at 310 °C. For a symmetric PS-b-PMMA block copolymer, the perpendicularly oriented lamellar morphology is obtained when the random layer thickness is higher than 3.5 nm, that is after 60 s RTP grafting time at 250 °C. In addition, TGA-GC-MS analysis indicates that a chain structural reorganization, which occurs during the RTP treatment at high temperature, affords a more stable film structure without changing its surface characteristics. In conclusion, the RTP technology allows the “grafting to” approach to be successfully integrated into the next generation lithographic processes and affords the unprecedented opportunity to study the grafting of macromolecules on time scales and in temperature ranges that have never been explored before, shedding new light on the early stages and on the dynamics of these processes.