METHOD FOR FORMING A TRENCH ISOLATION OF SEMICONDUCTOR DEVICES

摘要

PURPOSE: A trench isolation method is provided to improve trench isolation properties and prevent a gate poly stringer by preventing a recess phenomenon of an oxidation preventing layer. CONSTITUTION: A pad oxide(32) and an active nitride(34) are sequentially formed on a semiconductor substrate(30). A trench(38) is formed by etching the active nitride, the pad oxide and the semiconductor substrate using a trench mask(36), and then a portion of the active nitride(34) formed at both sides of the trench(38) is removed by wet etching. A thermal oxide(42), an oxidation preventing nitride(44) and an HTO(hot thermal oxide) layer(46) are sequentially formed on the resultant structure. At this time, since the area of the active nitride(34) is reduced, the surface area of the insulating layers(44,46) is increased. Thereby, a recess of the oxidation preventing nitride(44) and the HTO layer(46) is substantially prevented.