Patent ID: 7514312

Claim:
A method of manufacturing semiconductor devices, the method comprising: (a) providing a semiconductor substrate in which a cell region and a peripheral region are divided and an active region and a field region are defined; (b) sequentially forming a pad oxide film and a pad nitride film on the semiconductor substrate; (c) etching the pad nitride film and the pad oxide film of the field region in the cell region using a first photoresist pattern; (d) etching the semiconductor substrate in the field region of the cell region using a patterned pad nitride film as an etch mask to form first trenches in the semiconductor substrate; (e) forming a second photoresist pattern through which the field region defined in the peripheral region is exposed, wherein the second photoresist pattern covers over the first trenches; (f) etching the pad nitride film, the pad oxide film, and the semiconductor substrate using the second photoresist pattern as a mask, to form second trenches and to make rounded top corners of the semiconductor substrate in the peripheral region; (g) removing the second photoresist pattern; (h) forming isolation films within the first and second trenches; (i) removing the pad nitride film and the pad oxide film to expose the semiconductor substrate of the active region; and (j) forming a gate oxide film on the semiconductor substrate of the exposed active region.