Manufacturing method of semiconductor device with filling insulating film into trench

Abstract

Forming of a first silicon oxide film is started on an internal surface of a trench formed on a surface or upwardly of a semiconductor substrate according to an HDP technique. Then, deposition of the first silicon oxide film stops before an opening of the trench closes. Further, the first silicon oxide film deposited in the vicinity of an opening is etched, and a second silicon oxide film is formed on the first silicon oxide film deposited on the bottom of the trench according to the HDP technique. In this manner, the first and second silicon oxide films can be laminated on the bottom of the trench.

What is claimed is:  
     
         1 . A manufacturing method of a semiconductor device, comprising: 
 forming a trench on a surface of a semiconductor substrate;    oxidizing thermally an internal surface of the trench;    forming a first silicon oxide film into the trench with a high density plasma;    removing the first silicon oxide film formed on a side face of the internal surface until a part of the side face is exposed;    oxidizing thermally the part of the side face exposed; and    forming a second silicon oxide film on the first silicon oxide film and on the side face with a high density plasma.    
     
     
         2 . The manufacturing method of the semiconductor device of  claim 1 , wherein said removing includes isotropic wet etching.  
     
     
         3 . A manufacturing method of a semiconductor device, comprising: 
 forming a trench on a surface of a semiconductor substrate;    forming a first silicon oxide film into the trench with a high density plasma;    removing the first silicon oxide film formed on the surface until the surface is exposed; and    forming a second silicon oxide film on the first silicon oxide film and on the exposed surface with a high density plasma.    
     
     
         4 . The manufacturing method of the semiconductor device of  claim 3 , wherein said removing includes chemical mechanical polishing.  
     
     
         5 . A manufacturing method of a semiconductor device, comprising: 
 forming an insulating film on a semiconductor substrate,    forming a polysilicon film on the insulating film;    forming a trench penetrating the insulating film and the polysilicon film and dug in the semiconductor substrate;    forming a thermal oxide film on an internal surface of the trench by a oxidation of an oxygen radical; and    filling a first silicon oxide film into the trench with a high density plasma.    
     
     
         6 . The manufacturing method of the semiconductor device of  claim 5 , further comprising: 
 removing the first silicon oxide film formed on a side face of the internal surface until a part of the side face is exposed; and    forming a second silicon oxide film on the first silicon oxide film and on the side face with a high density plasma.    
     
     
         7 . A manufacturing method of a semiconductor device, comprising: 
 forming an insulating film on a semiconductor substrate;    forming a polysilicon film on the insulating film;    forming a trench penetrating the insulating film and the polysilicon film and dug in the semiconductor substrate;    forming a first thermal oxide film and a second thermal oxide film by a thermal oxidation of the semiconductor substrate and the polysilicon film on an internal surface of the trench,    forming a first silicon oxide film on the first thermal oxide film and the second thermal oxide film with a high density plasma;    removing the first silicon oxide film formed on an upper part of the second thermal oxide film; and    forming a second silicon oxide film on the first silicon oxide film with a high density plasma.    
     
     
         8 . The manufacturing method of the semiconductor device of  claim 7 , wherein in said forming the first silicon oxide film, a height of a lowest surface of the first silicon oxide film in the trench is higher than a height of a surface of the insulating film.  
     
     
         9 . A semiconductor device comprising: 
 a semiconductor substrate having a trench on a surface;    a first insulating film identified by a back face contacting with a bottom face and a lower part of a side face of the trench;    a bottom insulator identified by a bottom face and a side face contacting with a surface of said first insulating film;    a second insulating film identified by a back face contacting with an upper part of the side face of the trench and identified by an end face contacting with an end face of said first insulating film; and    a upper insulator identified by a side face contracting with a surface of said second insulating film and identified by a bottom face contacting an upper face of said bottom insulator.    
     
     
         10 . A semiconductor device comprising: 
 a semiconductor substrate having a trench on a surface;    an insulating film identified by a back face contacting with the surface of said semiconductor substrate and having a first opening on the trench;    a polysilicon film disposed on a surface of said insulating film and having a second opening over the trench;    a silicon oxide film identified by a back face contacting with a bottom face and a side face of the trench and a side face of the second opening of said polysilicon film and identified by an uniform film thickness; and    an insulator identified by a bottom face and a side face contacting with a surface of said silicon oxide film.    
     
     
         11 . The semiconductor device of  claim 10 , wherein an aspect ratio of the trench exceeds three.  
     
     
         12 . A semiconductor device comprising: 
 a semiconductor substrate having a first trench on a surface;    a silicon oxide film identified by a back face contacting with a bottom face and a side face of the first trench;    a bottom insulator identified by a bottom face and a side face contacting with a surface of said silicon oxide film and identified by an upper face having a second trench; and    an upper insulator identified by a bottom face and a side face contacting with the second trench and identified by a height of an upper face being equal to that of an upper face of said bottom insulator.    
     
     
         13 . A semiconductor device comprising: 
 a semiconductor substrate having a trench on a surface;    an insulating film identified by a back face contacting with the surface of said semiconductor substrate and having a first opening on the trench;    a polysilicon film disposed on a surface of said insulating film and having a second opening over the trench;    a first silicon oxide film contacting with a bottom face and a side face of the trench and a side face of the first opening;    a bottom insulator having a bottom face and a side face coming into contact with a surface of the silicon oxide film;    a second silicon oxide film identified by a back face contacting with said polysilicon film and identified by a surface contacting with said bottom insulator and identified by one end contacting with said insulating film and identified by a height of the other end being equal to that of an upper face of said bottom insulator; and    an upper insulator identified by a bottom face contacting with the other end of said second silicon oxide film and the upper face of said bottom insulator and identified by a side face contacting with a side face of said polysilicon film.