(181a) Fabrication of Nanostructures Via Directed Self-Assembly of Block Copolymers

One of the Bottom-up lithography methods, the block copolymer direct self-assembly technique, offers the potential to complement Top-down lithography due to cost effectiveness and the simple process. Self-assembled block copolymers through phase separation can be applied to fabricate nanotemplates to produce continuously evolving small devices such as memory devices.In this study, finger-print like lamella patterns at nanometer scale were fabricated via directed self-assembly of symmetric PS-b-PMMA copolymer (volume fraction ratio of two blocks = 5:5). Block copolymers composed of blocks with different chemical properties are oriented parallel to the substrate due to differences in surface energy. Therefore, the vertical orientation of the thin film was induced by controlling the properties of the surface using the random copolymer. Morphological changes of block copolymers were observed and measured by varying various process conditions. First, morphological evolution was intensively observed by varying the thickness of the block copolymer thin film. Morphological evolution was also intensively observed by varying the annealing process conditions leading to nanostructure formation of the microdomains. Finally, the PMMA block was selectively removed by UVO and acetic acid etching. Control of the etching time is required to produce a thin film of desired morphology and thickness. A metal will be selectively deposited in between the PS nanotrench patterns. Subsequently, the residual PS domains will be removed and the reliability of the metal nanopattern will be analyzed through finite element method (FEM) simulation.