Contact Hole Multiplication by Directed Self-Assembly of Block Copolymer with Homopolymer-Blending

Directed self-assembly (DSA) of cylindrical block copolymers (BCPs) with graphoepitaxy demonstrates great promise in contact hole multiplication at sub-7 nm technology nodes. However, achieving defect-free device patterns with conventional lithography remains a significant challenge. This study aims to investigate the impact of blending homopolymer polystyrene (PS) with BCP on the self-assembly behavior within confined elliptical spaces. Comprehensive experimental and simulation studies were conducted to examine different BCP blending systems. The results demonstrate that introducing homopolymer PS enables the formation of defect-free bi-pore structures in elongated elliptical template holes. Therefore, blending a homopolymer PS with BCP provides valuable insights for advanced lithography techniques, facilitating the fabrication of high-quality patterns at sub-7 nm technology nodes.