Semiconductor device and method of fabricating the same

Abstract

According to a method of fabricating a semiconductor device, a first mask pattern is used to etch first device isolation layers and active lines or form grooves, in which word lines will be provided. Thereafter, the active lines are etched in a self-alignment manner by using the first mask pattern as an etch mask. As a result, it is possible to suppress mask misalignment from occurring.

1 .- 8 . (canceled) 
     
     
         9 . A semiconductor device, comprising:
 a substrate; and   a word line provided in the substrate to extend along a first direction,   wherein the word line has a first width at a first height and a second width at a second height different from the first height, and the first and second widths are different from each other.   
     
     
         10 . The device of  claim 9 , wherein the word line has a convex-concave bottom surface. 
     
     
         11 . The device of  claim 9 , wherein the first height is higher than the second height and the first width is greater than the second width. 
     
     
         12 . The device of  claim 9 , wherein the first height is higher than the second height and the first width is smaller than the second width. 
     
     
         13 . The device of  claim 9 , further comprising:
 a plurality of line-shaped first device isolation layers extending along a second direction crossing the first direction; and   a second device isolation layer between the first device isolation layers and adjacent to a bottom surface of the word line.   
     
     
         14 . The device of  claim 13 , wherein a bottom surface of the second device isolation layer is rounded. 
     
     
         15 . The device of  claim 14 , wherein the first height is higher than the second height and the first width is smaller than the second width. 
     
     
         16 .- 20 . (canceled)