ELEMENT ISOLATION METHOD USING DOUBLE LOCAL OXIDATION OF SILICON PROCESS

摘要

The method uses a double LOCOS process to obtain an effective electrical isolation between the impurity diffusion regions having a field oxide film there between and the reduce the side diffusion length, when forming the field oxide film, thereby reducing a bird's beak shape. The method comprises forming a pad oxide film (2) and a nitride film (3) on a substrate (1) to leave the film (3) at a dummy active region (6) by patterning the film (3), forming a field oxide film (4) by a first LOCOS process, removing forming a pad oxide film (2) and a nitride film (3) thereon, patterning the nitride film (3) to leave the film (3) at an actual active region (7) and forming a field oxide film (4) by a second LOCOS process.