Synthesis and Characterization of New Block Copolymers for Direct Self-assembly

Due to its high resolution, easy process, and independence to complex optical exposure systems, Directed Self Assembly (DSA) is a promising alternative patterning technology in microlithography area. In this paper, a new block copolymer was designed and synthesized through anionic polymerization. It has large molecular weight and low PDI. The formation of lamellae was confirmed and the L₀ of the polymer was analysed by using Small Angle X-ray Scattering (SAXS) and 2D-Fourier transform of SEM images. ICP dry etch data showed that the two blocks had a good etch rate ratio, which was good for pattern transfer. A neutral underlayer was crafted for the BCP to phase separate on and form perpendicular features. Annealing temperature and time were investigated for the phase separation of this BCP/Neutral layer system. It could be found this system shows phase separation after spin coating, without any anneal step, by analysis of finger print patterns. 50 nm lines could be found after spin coating. The dependence of L₀ on MW is described along with approaches and results of directed self-assembly using graphoepitaxy and this polymer and neutral layer.