Methods of forming semiconductor trench and forming dual trenches, and structure for isolating devices

摘要

Methods of forming a semiconductor trench and forming dual trenches and a structure for isolating devices are provided. The structure for isolating devices is disposed in a substrate having a periphery area and an array area. The structure for isolating devices includes a first isolation structure and a second isolation structure. The first isolation structure has a profile with at least three steps and is disposed in the substrate in the periphery area. The second isolation structure has a profile with at least two steps and is disposed in the substrate in the array area.