Development of polycarbonate-containing block copolymers for thin film self-assembly applications

• Published in: Polymer chemistry 2016-01, Vol.7 (4), p.94-95
• Main Authors: Vora, Ankit, Wojtecki, Rudy J, Schmidt, Kristin, Chunder, Anindarupa, Cheng, Joy Y, Nelson, Alshakim, Sanders, Daniel P
• Format: Article
• Language: English
• ISSN: 1759-9954; 1759-9962
• DOI: 10.1039/c5py01846c

Access to well-defined materials is one of the key requirements for successful implementation of block copolymer-based lithography for advanced semiconductor nodes. We report on the development of polystyrene- b -polytrimethylene carbonate (PS- b -PTMC) block copolymer (BCP) using organocatalytic ring opening polymerization of trimethylene carbonate (TMC) from hydroxyl-functional polystyrene macroinitiator as a materials candidate for directed self-assembly applications. The impact of organocatalyst choice and the extent of TMC conversion on the quality of PS- b -PTMC BCP were studied using gel permeation chromatography and nuclear magnetic resonance (NMR) spectroscopy techniques. As a direct method to identify PTMC homopolymer content in the resulting BCPs, a new NMR-based technique was developed. Finally, the influence of BCP purity on the thin film morphology was studied using atomic force microscopy and grazing incidence small angle X-ray scattering techniques. Our results indicate that the PTMC homopolymer impurity negatively impacts the thin film morphology, which is extremely important for lithographic applications. High quality block copolymers are needed for thin film self-assembly and directed self-assembly applications.