METHOD FOR FORMING ISOLATION LAYER OF SEMICONDUCTOR DEVICE

摘要

PURPOSE: A method for forming an isolation layer of a semiconductor device is provided to simplify a process by utilizing a shallow trench isolation process using a nitride layer spacer. CONSTITUTION: A method for forming an isolation layer of a semiconductor device comprises the following steps. An ISO photoresist is formed to define an active area and an isolation area on a silicon substrate(31). A trench is formed by etching an exposed silicon substrate. A nitride layer is formed on an upper portion of the whole structure including the trench after removing the photoresist. The nitride layer of the upper portion of the silicon substrate and the nitride layer of a lower portion of the trench are removed by performing a blanket etch process. A nitride layer spacer(33A) is formed at a side wall of the trench. A high density plasma oxide layer(34) is formed on the upper portion of the whole structure. The silicon substrate is flattened and a gate oxide layer(35) is formed the upper portion of the whole structure.