Method of fabricating semiconductor memory device

Abstract

A method of fabricating a semiconductor device includes applying a coating oxide film to a surface of a substrate including a semiconductor substrate so that a recess formed in the surface is filled with the coating oxide film, applying a steam oxidation treatment to the substrate at a first temperature, soaking the substrate in heated water while applying a megasonic wave to the substrate in the heated water, and applying a steam oxidation treatment to the substrate at a second temperature higher than the first temperature.

1 . A method of fabricating a semiconductor device, comprising:
 applying a coating oxide film forming a solution to a recess formed in a surface of a substrate including a semiconductor substrate;   baking the substrate at a post-coating baking temperature and forming a coating oxide film so that the recess is filled with the coating oxidation;   soaking the substrate in heated water while applying a megasonic wave to the heated water; and   applying a steam oxidation treatment to the substrate.   
     
     
         2 . The method according to  claim 1 , wherein the coating oxide film includes polysilazane. 
     
     
         3 . The method according to  claim 1 , wherein the megasonic wave is applied to the heated water for several tens minutes or more. 
     
     
         4 . The method according to  claim 1 , wherein the heated water has a temperature which is at or above 50° C. 
     
     
         5 . The method according to  claim 1 , wherein the megasonic wave has a frequency ranging from several hundreds kHz to several MHz. 
     
     
         6 . The method according to  claim 1 , wherein the megasonic wave has output ranging from several tens W to 2 kW. 
     
     
         7 . The method according to  claim 1 , wherein the first temperature ranges from 200° C. to 400° C., and the second temperature is at or above 400° C. 
     
     
         8 . The method according to  claim 1 , wherein the substrate is configured into a film configuration including an insulating film for processing, and in the recess forming step, a trench for element isolation is formed in the semiconductor substrate as the recess. 
     
     
         9 . The method according to  claim 1 , wherein the substrate has a film structure for forming a gate electrode on the semiconductor substrate, and in the recess forming step, the film structure is etched so that a plurality of gate electrodes are separately formed.