Method for forming isolation region of semiconductor device

Abstract

A method for forming an isolation region of a semiconductor device to improve isolation characteristics between semiconductor devices. A first insulating layer is formed on a substrate, and a second insulating layer is formed on the first insulating layer. A field region of the substrate is defined by selectively removing the second insulating layer. A portion of the surface of the substrate is then exposed by selectively removing the first insulating layer using the second insulating layer as a mask. A third insulating layer is formed on the exposed portion of the substrate. Then insulating sidewalls are formed on sides of the first and second insulating layers. Next, a trench is then formed in the substrate using the second insulating layer and the insulating sidewalls as masks. Finally, a field oxide layer is formed in the trench to isolate semiconductor devices.

Dependencies are inferred from the claim text.