Integrated circuit devices including an element having a non-linear shaped upper surface and methods of forming the same

Abstract

Integrated circuit devices and methods of forming the same are provided. The methods may include sequentially forming an underlying mask layer and a preliminary first mask layer on a substrate, forming a first mask structure by removing a portion of the preliminary first mask layer, and then forming a preliminary second mask layer. The preliminary second mask layer may enclose the first mask structure in a plan view. The methods may also include forming a second mask structure by removing a portion of the preliminary second mask layer and forming a vertical channel region including a portion of the substrate by sequentially etching the underlying mask layer and the substrate. The second mask structure may be connected to the first mask structure, and etching the underlying mask layer may be performed using the first and the second mask structures as an etch mask.