SEMICONDUCTOR DEVICE WITH DEEP TRENCH ISOLATION

A semiconductor device is provided. The semiconductor device includes a first region having a first gate structure disposed on a substrate and a second region having a second gate structure disposed on the substrate, a hard mask formed on the substrate, the first gate structure, and the second gate structure, a deep trench formed in the substrate between the first region and the second region, and formed to penetrate the hard mask to reach an inside of the substrate, and a planarized gap-fill insulating layer formed on the second gate structure and formed inside the deep trench. A topmost surface of the planarized gap-fill insulating layer and a topmost surface of the hard mask are coplanar.