Abstract: A method for preparing a semiconductor device is provided. The method for preparing the semiconductor device includes: providing a substrate, and forming a first dielectric layer on one side of the substrate, where the substrate includes an array area and a peripheral area arranged outside of the array area; forming an initial mask pattern on one side of the first dielectric layer away from the substrate; performing at least two patterning processes on the initial mask pattern, to form a first mask pattern in the array area and to form a second mask pattern in the peripheral area. The first mask pattern has a first height, the second mask pattern has a second height, and the second height is greater than the first height. Both of the array area and the peripheral area are exposed by using each of the at least two patterning processes.