METHOD FOR MANUFACTURING A TRENCH ISOLATION

摘要

PURPOSE: A trench isolation forming method is provided to reduce an etching speed of a silicon nitride liner and a dent of an edge portion of a trench by forming the silicon nitride liner between a thermal oxide and a trench isolating layer. CONSTITUTION: The method comprises the steps of forming a trench etching mask on a semiconductor substrate(100); forming a trench(104) by etching the semiconductor substrate using the trench etching mask as a mask; growing a thermal oxide layer(105) at both sidewalls and the bottom of the trench; forming a high temperature oxide(106) on the thermal oxide(105) and the semiconductor substrate; forming a SiN liner(107) on the high temperature oxide in order to prevent oxidation of the inner wall of the trench; filling a trench isolation layer(108) into the trench(104); polishing or etch-back the trench oxidation layer(108), the SiN liner(107) and the high temperature oxide(106) to expose the surface of the trench etching mask; and removing the trench etching mask.