Semiconductor devices and methods of forming a trench in a semiconductor device

Abstract

Semiconductor devices and methods to form a trench in a semiconductor device are disclosed. A disclosed process comprises: forming a hollow by etching a portion of a semiconductor substrate; forming a side wall layer in an inner side wall of the hollow; forming a trench by further etching the semiconductor substrate exposed through the bottom of the hollow; and filling the trench by forming an insulation film on the side wall layer and the trench.

1 . A semiconductor device comprising: 
 a trench formed in a semiconductor substrate;    a side wall layer formed on an inner side wall of the trench; and    an insulation film formed on the side wall layer and the trench for filling the trench.    
     
     
         2 . A semiconductor device as defined in  claim 1 , wherein the side wall layer is formed at a predetermined height from a top surface of the semiconductor substrate.  
     
     
         3 . A semiconductor device as defined in  claim 1 , wherein a height of the side wall layer is less than a depth of the trench.  
     
     
         4 . A semiconductor device as defined in  claim 1 , wherein the side wall layer has a width of approximately 200-400 Å measured from the inner side wall of the trench.  
     
     
         5 . A semiconductor device as defined in  claim 1 , wherein the side wall layer comprises a silicon nitride film.  
     
     
         6 . A semiconductor device as defined in  claim 1 , wherein the insulation film comprises an oxide film.  
     
     
         7 . A method of forming a trench in a semiconductor device comprising: 
 forming a hollow by etching a portion of a semiconductor substrate;    forming a side wall layer on an inner side wall of the hollow;    forming a trench by further etching the semiconductor substrate exposed through the bottom of the hollow; and    filling the trench by forming an insulation film on the side wall layer and the trench.    
     
     
         8 . A method as defined in  claim 7 , wherein the side wall layer has a width of approximately 200-400 Å measured from the inner side wall of the trench.  
     
     
         9 . A method as defined in  claim 7 , wherein the side wall layer comprises a silicon nitride film.  
     
     
         10 . A method as defined in  claim 7 , wherein the insulation film comprises an oxide film.  
     
     
         11 . A method as defined in  claim 7 , wherein forming the side wall layer on the inner side wall of the hollow further comprises: 
 forming a sacrificial layer on the hollow and the semiconductor substrate; and    forming the side wall layer by etching back the sacrificial layer such that the sacrificial layer remains on the inner side wall of the hollow.    
     
     
         12 . A method as defined in  claim 11 , wherein the sacrificial layer comprises a silicon nitride film.  
     
     
         13 . A method as defined in  claim 11 , wherein the side wall layer has a width of approximately 200-400 Å measured from the inner side wall of the hollow.  
     
     
         14 . A method as defined in  claim 7 , further comprising: 
 before forming the hollow, forming a pad oxide layer and a polishing stop layer,    wherein the hollow is formed by etching the polishing stop layer, the pad oxide layer and the semiconductor substrate.    
     
     
         15 . A method as defined in  claim 14 , wherein the polishing stop layer comprises a silicon nitride film.  
     
     
         16 . A method as defined in  claim 14 , wherein the pad oxide layer is formed at a thickness of approximately 100-300 Å.  
     
     
         17 . A method as defined in  claim 14 , wherein the polishing stop layer is formed at a thickness of approximately 1500-3000 Å.  
     
     
         18 . A method as defined in  claim 14 , wherein the insulation film is formed to fill the trench on entire surfaces of the polishing stop layer, the side wall layer and the trench, and the insulation film is then chemically mechanically polished until the polishing stop layer is exposed.  
     
     
         19 . A method as defined in  claim 18 , wherein the insulation film comprises an oxide film.  
     
     
         20 . A method as defined in  claim 7 , wherein, before the insulation film is formed, a liner oxide layer is formed on the side wall layer and the trench, and the insulation film is then formed on the liner oxide layer to fill the trench.