A processing method is disclosed that enables an improved directed self-assembly (DSA) processing scheme by allowing the formation of improved guide strips in the DSA template that may enable the formation of sub-30 nm features on a substrate. The improved guide strips may be formed by improving the selectivity of wet chemical processing between different organic layers or films. In one embodiment, treating the organic layers with one or more wavelengths of ultraviolet light may improve selectivity. The first wavelength of UV light may be less than 200 nm and the second wavelength of UV light may be greater than 200 mn.