Manufacturing method of semiconductor devices

Abstract

An element isolation method of a semiconductor device comprises the steps of forming an oxide film on a semiconductor substrate; forming a nitride film on the oxide film; forming an isolation trench on the semiconductor device, the isolation trench being formed through the nitride film and oxide film; forming an oxide insulation layer on the semiconductor substrate to fill the isolation trench and cover the nitride film; flattening the surface of the semiconductor substrate to expose the nitride film by removing a surface portion of the oxide insulation layer in the isolation trench and the oxide insulation layer on the nitride film; heating the flattened semiconductor substrate in a nitrogen-containing gas atmosphere under reduced pressure to form an oxy-nitride film at an interface between an inside wall of the isolation trench and the oxide insulation layer in the isolation trench; and removing the nitride film and the oxide film on the semiconductor substrate.

What is claimed is:  
     
         1 . A method for manufacturing a semiconductor device, comprising the steps of: 
 forming an oxide film on a semiconductor substrate;    forming a nitride film on the oxide film;    forming an isolation trench on the semiconductor device, the isolation trench being formed through the nitride film and oxide film;    forming an oxide insulation layer on the semiconductor substrate to fill the isolation trench and cover the nitride film;    flattening the surface of the semiconductor substrate to expose the nitride film by removing a surface portion of the oxide insulation layer in the isolation trench and the oxide insulation layer on the nitride film;    heating the flattened semiconductor substrate in a nitrogen-containing gas atmosphere under reduced pressure to form an oxy-nitride film at an interface between an inside wall of the isolation trench and the oxide insulation layer in the isolation trench; and    removing the nitride film and the oxide film on the semiconductor substrate.    
     
     
         2 . The method for manufacturing a semiconductor device according to    claim 1   , wherein the nitrogen containing gas atmosphere comprises at least one selected from the group consisting of NO, N 2 O, NO 2  and NH 3 .  
     
     
         3 . The method for manufacturing a semiconductor device according to    claim 1   , wherein the reduced pressure of the nitrogen-containing atmosphere is less than 1 atm.  
     
     
         4 . A method for manufacturing a semiconductor device, comprising the steps of: 
 forming a first oxide film on a semiconductor substrate;    forming a nitride film on the first oxide film;    forming an isolation trench on the semiconductor substrate, the isolation trench being formed through the nitride film and first oxide film;    forming a second oxide layer on a surface of the isolation trench;    heating the semiconductor substrate having the isolation trench in a nitrogen-containing gas atmosphere under reduced pressure to form an oxy-nitride film on a surface of the isolation trench;    forming an oxide insulation layer on the semiconductor substrate to fill the isolation trench and cover the nitride film;    flattening a surface of the semiconductor substrate by removing a surface portion of the oxide insulation layer in the isolation trench and the oxide insulation layer on the nitride film; and    removing the nitride film and the first oxide film on the semiconductor substrate.    
     
     
         5 . The method for manufacturing a semiconductor device according to    claim 4   , wherein the nitrogen containing gas atmosphere comprises at least one selected from the group consisting of NO, N 2 O, NO 2  and NH 3 .  
     
     
         6 . The method for manufacturing a semiconductor device according to    claim 4   , wherein the reduced pressure of the nitrogen-containing atmosphere is less than 1 atm.