Synthesis and morphology studies of polysiloxane-based triblock copolymers

Abstract

The directed self-assembly (DSA) behavior of block copolymers (BCPs) has recently been widely studied because of its potential application to the nanofabrication of semi-conductors. In this study, a novel molecular design based on the A-B-C triblock copolymer was developed: polystyrene-b-poly(dimethyl siloxane)-b-poly(substituted siloxane) (PS-b-PDMS-b-PMSCXOH, where X = 3 or 6). The high χ parameter between the PS and PDMS segments was expected to effectively reduce line edge roughness (LER) and resulted in a smooth interface with a lamellar nanostructure. The high etching resistance of Si-containing blocks also facilitates the potential pattern transfer to Si substrate. Small-angle X-ray scattering (SAXS) and transmission electron microscopy (TEM) were used to reveal the self-assembly morphologies of A-B-C triblock copolymers, which are more complex compared to commonly studied binary system of A-B diblock copolymer. The reduced interface roughness in the microphase-separated nanostructures that can lead to reducing LER of patterns observed in bulk.