A specific type of buried defect in lamellar phase diblock copolymer was studied by experiments and simulations using self-consistent field theory (SCFT). The defects had 3-dimensional structures and created hexagonally arranged holes. They existed not only on the substrate with the guide structures but in fingerprints. The simulation results suggested that one of the causes of the defects is mismatch of the surface affinity of the neutral layer.

This paper introduces a fabrication method to achieve sub-15 nm line-and-space (L/S) patterns by combining grapho- and chemo-epitaxy using poly(styrene-block-methyl methacrylate) copolymer (PS-b-PMMA). The fabrication method is simple, since it eliminates photoresist stripping and also does not require any special materials to form pinning patterns. In this process, the ridges formed on spin-on-glass (SOG) surface work as physical guides and the photoresists on them are utilized as a pinning layer. Fine PS-b-PMMA L/S patterns were obtained in sufficient critical dimension (CD) range of the guide patterns that corresponded to the 15% dose margin using ArF immersion lithography. 3-dimensional grid defects were found to be the origin of the short defects. The half-pitch (hp) 15 nm L/S patterns were transferred successfully to SOG/spin-on-carbon (SOC) stacked substrate.

We also describe fabrication of sub-10 nm L/S patterns using a high-chi block copolymer (BCP).