Hoong Joo Lee

Structural Properties of Potassium Encapsulated in Carbon Nanotubes

We have investigated structural phases of potassium in carbon nanotubes using a structural optimization process applied to an atomistic simulation method. As the radius of the carbon nanotubes is increased, various structural phases ranging from an atomic strand to multi-shell packs composed of coaxial cylindrical shells and helical, layered, and crystalline structures are found to emerge. Numbers of helical atom rows composed of coaxial tubes and orthogonal vectors of a circular rolling of a triangular network can explain multi-shell phases of potassium in carbon nanotubes.

Suppression of sidelobe and overlap error in AttPSM metal layer lithography using rule-based OPC

Overlap errors and sidel-lobe printing caused by the design rule reduction in the lithography using attenuated phase shift mask have become serious. Overlap errors and side-lobes can be simultaneously solved by the rule-based correction using scattering bars with the rules extracted from test patterns. Process parameters affecting the attPSM lithography simulation have been determined by the fitting method to the process data. Overlap errors have been solved applying the correction rules to the metal patterns overlapped with contact or via. Moreover, the optimal insertion rule of the scattering bars has made it possible to suppress the side-lobes and to enhance DOF at the same time. Compared to the existing Cr shield method, the proposed rule-based correction with scattering bars can reduce the process complexity and time for mask production.