A method of forming patterns for a semiconductor device includes preparing a hardmask composition including a carbon allotrope, a spin-on hardmask (SOH) material, an aromatic ring-containing polymer, and a solvent, applying the hardmask composition to an etching target layer, forming a hardmask by heat-treating the applied hardmask composition, forming a photoresist pattern on the hardmask, forming a hardmask pattern by etching the hardmask using the photoresist pattern as an etching mask, and forming an etched pattern by etching the etching target layer using the hardmask pattern as an etching mask.