ELEMENT ISOLATION STRUCTURE OF SEMICONDUCTOR AND METHOD FOR FORMING THE SAME

摘要

PURPOSE: A device isolation structure of a semiconductor device and a forming method thereof are provided to prevent poly stringer by forming a deep trench inside a shallow trench. CONSTITUTION: A semiconductor substrate(101) includes an inactive region and an active region. A deep trench(121) is formed in the inactive region of the semiconductor substrate. A shallow trench(131) is overlapped with the deep trench. An oxide film(133) and a first device isolation pattern are formed in the deep trench. A second device isolation pattern is contacted with the first device isolation pattern.