METHOD OF FORMING AN ISOLATION FILM IN SEMICONDUCTOR DEVICE

摘要

A method for forming an isolation layer of a semiconductor device is provided to improve EFH(effective field oxide height) variation in a cell region without causing contamination of photoresist and a lifting-off phenomenon of a photoresist pattern by performing a wet etch process using an etch mask as a patterned sacrificial layer in a peripheral circuit region during a process for etching an isolation layer for controlling EFH in the cell region. A trench(112) is formed in an isolation region of a cell region and a peripheral circuit region in a semiconductor substrate(100). The trench is filled with an isolation layer(114). A sacrificial layer(116) and a photoresist pattern are sequentially formed on the isolation layer. By using the photoresist pattern as an etch mask, the sacrificial layer is patterned to remove the sacrificial layer in the cell region. The photoresist pattern is removed. The isolation layer in the cell region is etched by using the patterned sacrificial layer as an etch mask. A tunnel insulation layer(102a), an electron storage layer(104) and a hard mask(110) can be formed on the semiconductor substrate in an active region of the cell region.