In this study, we introduce a simple and effective method to induce directed self-assembly (DSA) of symmetric block copolymers (BCPs) on large area using soft grating patterns. By physically rubbing poly(tetrafluoro ethylene) (PTFE) at various temperatures near its melting point, the horizontally aligned PTFE grating patterns with ~ 20nm in amplitude and ~ 200nm in pitch distance are produced on flat Si substrates due to its low friction coefficient and high wear rate. Then thin films of symmetric polystyrene-block-poly(methyl methacrylate) copolymers (PS-b-PMMA) form on the patterned substrates as spin-coated at 2000 rpm. To induce BCP self-assembly on the patterned surface, the thin films are solvent-annealed in vapor of organic solvents like acetone, tetrahydrofuran, toluene. Even though initial morphology of the as-spun BCP thin films is irregular, the parallel orientation of lamellar nanostructures of PS-b-PMMA is generated after solvent-annealing process. Interestingly, it is observed that those lamellar nanostructures are aligned along the pitch of underlying PTFE grating patterns and their ordering behavior are surprisingly improved by the grating patterns as compared to the BCP morphology on flat substrates. As the BCP patterns are used as templates for metal (Au, Ag, Pt) deposition process, extremely aligned metal nano-wires can be produced on the Si substrates. The ordering behavior of BCP thin films on the patterned surface is characterized by using atomic force microscopy (AFM) and scanning electron microscopy (SEM).