PATTERN FORMING METHOD, SEMICONDUCTOR MEMORY DEVICE, AND METHOD OF MANUFACTURING THE SAME

A method of forming a pattern includes forming an etch target layer over a substrate including a first area and a second area, forming a hardmask structure over the etch target layer, forming a photoresist pattern including a first photoresist pattern including an engraved pattern located in the first area and a second photoresist pattern including an embossed pattern located in the second area, forming an upper hardmask pattern including a plurality of openings, forming a reversible hardmask pattern filling the plurality of openings in the first area, and forming a feature pattern including a first pattern located in the first area and a second pattern located in the second area, wherein the first pattern includes a plurality of island patterns and a dam structure planarly surrounding the plurality of island patterns.