A COF substrate may include a base film, first upper conductive patterns, at least one second upper conductive pattern and lower conductive patterns. The first upper conductive patterns may be arranged on an upper surface of the base film. Each of the first upper conductive patterns may have an inner pattern and an outer pattern spaced apart from each other. The second upper conductive pattern may be arranged on the upper surface of the base film between the first upper conductive patterns. The lower conductive patterns may be arranged on a lower surface of the base film. The lower conductive patterns may be electrically connected between the inner pattern and the outer pattern. Thus, conductive materials causing a short between the panel patterns may not exist between the inner pattern and the outer pattern on the upper surface of the base film.