METHOD FOR MANUFACTURING A TRENCH ISOLATION

摘要

PURPOSE: A trench isolation method is provided to improve a reliability and prevent a bridge due to a poly stringer generated in a dent portion by removing SiN liner dent formed at edge portions of the trench. CONSTITUTION: A trench(108) is formed by etching a semiconductor substrate(100) using a trench etching mask(106). After a thermal oxide(110) is formed in the trench, a SiN liner(112) is formed on the trench etching mask and the thermal oxide. A trench isolating layer(114) is formed by filling the trench. H3PO4 strip process is performed to remove the trench etching mask(106) while a portion of the SiN liner(112) is both etched, thereby generating a SiN liner dent(115). A poly spacer(116a) is formed at the dent portion(115) by filling a polysilicon layer into the dent portion, and then an oxide layer(118) is formed by oxidation the poly spacer(116a). Thereby, a bridge is prevent when a gate poly formation.