TRENCH ISOLATION TYPE SEMICONDUCTOR DEVICE AND METHOD FOR FORMING TRENCH ISOLATION LAYER

摘要

PURPOSE: A trench isolation layer formed in a trench with high aspect ratio is provided to prevent a silicon nitride liner from being damaged when lower and upper parts of the trench are filled with different insulating materials. CONSTITUTION: The silicon nitride liner(15) is formed on a substrate(10) in which the trench for device isolation is formed by trench etching. As a protection layer, a silicon oxide liner(17) such as HTO is overlaid on the silicon nitride liner(15) by CVD. The silicon oxide liner(17) is then subjected to densification at high temperature of 800°C or more. Next, the first insulating material such as SOG is filled in the trench and partially removed by etching. When the first insulating material is etched from the upper part of the trench, the silicon oxide liner(17) prevents the damage of the silicon nitride liner(15). Next, the second insulating material(25) such as HDP CVD is filled in the upper part of the trench.