A display device which can prevent a contact defect of a driver IC and a manufacturing method thereof are disclosed. According to the method, a plurality of pattern lines and a plurality of contact electrodes on a substrate are formed. Each pattern line and each contact electrode are connected each other. Anisotropic conductive films, in which a plurality of conductive balls are included, on the substrate are arranged. A plurality of driving circuits on the substrate and allowing bumps of the driving circuits to be opposite the anisotropic conductive films are arranged. Pressure and heat are applied to the driving circuits such that the bumps of the driving circuits allow the conductive balls to be electrically connected to the contact electrodes. A plurality of contact layers connected with the conductive balls are formed by irradiating laser light on contact regions to melt the pattern lines and the contact electrodes.