Method for fabricating semiconductor device

Abstract

A method for fabricating a semiconductor device includes etching a substrate to form a plurality of trenches, forming first liner layers over bottom surfaces and inner sidewalls of the trenches to a first height, forming sacrificial liner layers on one of the inner sidewalls of the trenches where the first liner layers are formed, forming third sacrificial layers to a second height, so that the third sacrificial layers are buried over the trenches where the sacrificial liner layers are formed, removing portions of the sacrificial liner layers exposed by the third sacrificial layers to form sacrificial patterns, forming second liner layers on the inner sidewalls of the trenches exposed by the third sacrificial layers, and removing the third sacrificial layers to form side contact regions opening one of the inner sidewalls of the trenches in a line form.

1 - 19 . (canceled) 
     
     
         20 . A method for fabricating a semiconductor device, comprising:
 etching a substrate to form a plurality of trenches;   forming first liner layers over bottom surfaces and inner sidewalls of the trenches to a first height;   forming side contact conductive layers on first inner sidewalls of the trenches exposed by the first liner layers;   forming third sacrificial layers to a second height which is higher than the first height, so that the third sacrificial layers are buried over the trenches where the side contact conductive layers are formed; and   removing portions of the side contact conductive layers exposed by the third sacrificial layers to form side contacts in a line form on second inner sidewalls, opposite from the first inner sidewalls, of the trenches.   
     
     
         21 . The method of  claim 20 , wherein the forming of the first liner layers comprises:
 forming a first liner over the surface profile of the trenches;   forming first sacrificial layers buried over the trenches to the first height; and   removing portions of the first liner exposed by the first sacrificial layers.   
     
     
         22 . The method of  claim 21 , wherein the forming of the side contact conductive layers on the first inner sidewalls of the trenches comprises:
 forming conductive layers for forming side contacts on the inner sidewalls of the trenches exposed by the first sacrificial layers;   forming a mask pattern covering the first inner sidewalls of the trenches; and   removing exposed portions of the conductive layers using the mask pattern.   
     
     
         23 . The method of  claim 22 , further comprising:
 forming a second sacrificial layer buried over the trenches, after the forming of the conductive layers; and   etching the second sacrificial layer to a certain thickness to expose the conductive layers using the mask pattern.   
     
     
         24 . The method of  claim 20 , further comprising forming second liner layers on the inner sidewalls of the trenches exposed by the third sacrificial layers. 
     
     
         25 . The method of  claim 20 , further comprising:
 forming doped polysilicon layers buried over the trenches where the side contacts are formed;   performing a thermal treatment process to silicide the side contacts buried over side contact regions; and   removing the doped polysilicon layers.   
     
     
         26 . A method for fabricating a semiconductor device, comprising:
 etching a substrate including a cell region and an edge region to form a plurality of trenches;   forming a first liner layer over the surface profile of the trenches;   forming first sacrificial layers over the trenches to a first height;   forming a mask pattern covering the edge region;   removing portions of the first liner layer exposed by the first sacrificial layers and the mask pattern;   forming side contact conductive layers on one of the inner sidewalls of the trenches in the cell region;   forming third sacrificial layers to a second height which is higher than the first height, so that the third sacrificial layers are buried over the trenches; and   removing portions of the side contact conductive layers exposed by the third sacrificial layers to form side contacts in a line form on one of the inner sidewalls of the trenches.   
     
     
         27 . The method of  claim 26 , wherein the forming of the side contact conductive layers on one of the inner sidewalls of the trenches comprises:
 forming conductive layers for forming side contacts on the inner sidewalls of the trenches exposed by the first sacrificial layers;   forming a mask pattern covering one of the inner sidewalls of the trenches in the cell region; and   removing exposed portions of the conductive layers using the mask pattern.   
     
     
         28 . The method of  claim 27 , further comprising:
 forming a second sacrificial layer buried over the trenches, after the forming of the conductive layers; and   etching the second sacrificial layer to a certain thickness to expose the conductive layers using the mask pattern.   
     
     
         29 . The method of  claim 26 , further comprising forming second liner layers on the inner sidewalls of the trenches exposed by the third sacrificial layers, after the removing of portions of the side contact conductive layers. 
     
     
         30 . The method of  claim 26 , further comprising:
 forming doped polysilicon layers buried over the trenches where the side contacts are formed;   performing a thermal treatment process to silicide the side contacts buried over side contact regions; and   removing the doped polysilicon layers.