Flash memory device and method of manufacturing the same

Abstract

A non-volatile memory device includes a semiconductor substrate having an active region defined by isolation films that extend along a first direction. A control gate line extends along in a second direction perpendicular to the first direction. First and second floating gates are formed on the active region and below the control gate line. An island conductive line is formed between the first and second floating gates and within the isolation films. The island conductive line extends along the first direction and is configured to receive a voltage in order to prevent interference between the first and second floating gates.

1 . A method of manufacturing a non-volatile memory device, the method comprising:
 etching a semiconductor to form a trench;   providing a first insulating layer within the first trench without completely filling the trench, so that a groove is formed within the trench;   providing a conductive layer within the groove, so that the conductive layer remains only at a lower portion of the groove to define an island conductive line;   forming a second insulating layer within the groove and over the island conductive line, wherein the first and second insulating layers define an isolation structure, the island conductive line being provided within the isolation structure;   forming first and second floating gates on first and second sides of the isolation structure, so that the isolation structure is provided between the first and second floating gates; and   forming a control gate line over the first and second floating gates.   
   
   
       2 . The method as claimed in  claim 1 , wherein the first insulating layer and the second insulating layer are formed using a high density plasma oxide film. 
   
   
       3 . The method as claimed in  claim 1 , wherein the providing-a-conductive-layer-within-the-groove step includes:
 providing a polysilicon layer within the groove and over the first insulating layer; and   etching the polysilicon layer until the polysilicon layer remains only at a lower portion of the groove.   
   
   
       4 . A method of manufacturing a non-volatile memory device, the method comprising:
 forming a tunnel oxide film and a first polysilicon layer on a semiconductor substrate;   etching the first polysilicon layer, the tunnel oxide film, and a portion of the semiconductor substrate to form an isolation trench arranged in a first direction;   forming a first insulating layer within the isolation trench to form a groove defined by the first insulating layer;   forming an island polysilicon line at a lower portion of the groove;   forming a second insulating layer within the groove and over the island polysilicon line to define an isolation structure, the isolation structure including the first and second insulation layers, the island polysilicon layer being provided within the isolation structure;   forming second polysilicon layer on the first polysilicon layer to form a floating gate having a lamination film of the first polysilicon layer and the second polysilicon layer; and   forming a control gate over the second polysilicon layer.   
   
   
       5 . The method as claimed in  claim 4 , wherein the first insulating layer and the second insulating layer are formed using a high density plasma oxide film. 
   
   
       6 . The method as claimed in  claim 4 , wherein forming island polysilicon line comprises:
 forming a polysilicon layer on the entire surface of the semiconductor substrate in which the first insulating layer is formed; and   etching back the polysilicon layer so that the polysilicon layer remains only at the lower portion of the groove.   
   
   
       7 . The method as claimed in  claim 4 , wherein the etching of the first polysilicon layer, the tunnel oxide film, and the semiconductor substrate is performed using a hard mask film as a mask. 
   
   
       8 . The method as claimed in  claim 4 , the isolation trench has a depth of about 2000 Å. 
   
   
       9 . The method as claimed in  claim 7 , wherein the hard mask film is a nitride film.