Fabrication of nano-line patterns via directed self-assembly of silicon-containing block copolymers

Abstract

Directed self-assembly of a polystyrene-block-poly(4-(tert-butyldimethylsilyl)oxystyrene), PS-b-PSSi diblock copolymer has been investigated for nanolithography applications. Nanopatterns with various line widths were fabricated with different molecular weights either parallel cylinder BCPs or perpendicular lamellar BCPs. Since organic-inorganic block copolymers have a large difference in etch resistance between the organic and inorganic blocks, sub-20-nm lines of silicon oxide can be directly produced upon oxygen plasma treatment. Parallel cylinder nanodomains were obtained by using a single selective solvent. And perpendicular lamellar nanodomains were obtained simply by adjusting the relative composition of selective and non-selective solvents in the annealing solvent. The use of a PS-brush substrate surface treatment are especially advantageous for achieving long-rage ordering and minimizing defect densities, and the Si content in PSSi leaves a robust oxide etch mask after one-step reactive ion etching. In case of graphoepitaxally directed self-assembly, we used the PS-brush treated silicon trench substrate, could obtained silicon oxide line pattern within the trench using both parallel cylinder pattern and perpendicular lamellar pattern. In case of chemoepitaxally directed self-assembly, we fabricated chemical pre-pattern through crosslinking of the BCP line patterns. It was possible to overcoating and solvent vapor treatment, we could obtain final silicon oxide line pattern over the chemical pre-pattern, successfully. In addition, with thermal treatment to the solvent annealing, it was able to shorten processing time effectively.