The present application discloses a method of forming a semiconductor structure. In at least one embodiment, the method includes forming a polysilicon layer over a substrate. A mask layer is formed over the polysilicon layer. The mask layer is patterned to form a patterned mask layer. A polysilicon structure is formed by etching the polysilicon layer using the patterned mask layer as a mask. The polysilicon structure has an upper surface and a lower surface, and the etching of the polysilicon layer is arranged to cause a width of the upper surface of the polysilicon structure greater than that of the lower surface of the polysilicon structure.