METHOD FOR FORMING A TRENCH ISOLATION

摘要

PURPOSE: A trench isolation forming method is provided to prevent a liner dent and a short fail of a gate electrode using a spacer as a mask pattern for forming the trench. CONSTITUTION: The STI(shallow trench isolation) method comprises the steps of: forming a first and a second insulating layers(102,104) on a semiconductor substrate(100); patterning the second insulating layer(104) using a desired mask pattern; forming a spacer(106) having different etching selectivity compared to the second insulating layer(104) at both sidewalls of the second insulating layer(104); forming a trench(107) by sequentially etching the first insulating layer(102) and the semiconductor substrate(100) using the second insulating pattern and the spacer(106) as a mask; forming a third insulating layer(108) at bottom and both sidewalls of the trench(107); forming a fourth insulating layer(110) and a fifth insulating layer(112) for filling the trench; flattening the fifth and the fourth insulating layers to expose the second insulating layer(104); removing the second insulating layer(104); and forming a trench isolation by etching the first insulating layer(102), the spacer(106) and a portion of the fifth insulating layer(112).