A method of forming a three-dimensional lithographic pattern is provided. The method includes providing a substrate. A first photoresist layer is formed on the substrate. The first photoresist layer corresponds to a first exposure removal dose. A second photoresist layer is formed on the first photoresist layer. The second photoresist layer corresponds to a second exposure removal dose, which is different from the first exposure removal dose. A reticle with multiple regions of different light transmittances is provided. Through the reticle, the first and second photoresist layers are exposed to form a first removable region in the first photoresist layer and a second removable region in the second photoresist layer. The second removable region is different from the first removable region. The first and second photoresist layers are then developed to remove the first and second removable regions.