Provided is a method of forming a pattern for an integrated circuit. The method includes forming a first layer over a substrate, wherein the first layer's etch rate is sensitive to a radiation, such as an extreme ultraviolet (EUV) radiation or an electron beam (e-beam). The method further includes forming a resist layer over the first layer and exposing the resist layer to the radiation for patterning. During the exposure, various portions of the first layer change their etch rate in response to an energy dose of the radiation received therein. The method further includes developing the resist layer, etching the first layer, and etching the substrate to form a pattern. The radiation-sensitivity of the first layer serves to reduce critical dimension variance of the pattern.