Patent ID: 6080637
Filing Date: 2000-06-27
Classification: H01L,Y10S

Abstract:
A method of forming an insulator filled, shallow trench, isolation region, in a semiconductor substrate, comprising the steps of:forming a composite insulator on said semiconductor substrate comprised of an underlying pad oxide layer, a silicon nitride layer, and an overlying capping silicon oxide layer;creating an opening in said composite insulator layer, using a photoresist shape as a mask, exposing top surface of semiconductor substrate;creating a shallow trench, in said semiconductor substrate, using said photoresist shape as a mask;performing a thermal oxidation procedure, to grow a sidewall silicon dioxide layer, on the exposed surfaces of said shallow trench, while forming a thin sidewall silicon oxide layer, on the sides of said silicon nitride layer, exposed in said opening, in said composite insulator layer;performing a first wet etch procedure to remove said thin sidewall silicon oxide layer, from the sides of said silicon nitride layer;performing a second wet etch procedure, to laterally recess silicon nitride layer, under said capping silicon oxide layer, and exposing a portion of said pad oxide layer, located adjacent to the edges of said shallow trench;depositing a thick silicon oxide layer, completely filling said shallow trench, completely filling said opening in said composite insulator layer, including completely filling region of laterally recessed silicon nitride layer, and with said thick silicon oxide layer overlying the top surface of said capping silicon oxide layer;removing a portion of said thick silicon oxide layer, and said capping silicon oxide layer, from the top surface of said silicon nitride layer, creating a ""T"" shaped insulator, comprised of a narrow, thick silicon oxide shape, located in said shallow trench, and a wide, thick silicon oxide shape, overlying said narrow, thick silicon oxide shape, and overlying said portion, of said pad oxide layer, located adjacent to the edges of said shallow trench;removing said silicon nitride layer; andremoving said wide, thick silicon oxide shape, and said pad oxide layer, to form said insulator filled, shallow trench.