Cylinder-Type Capacitor and Storage Device, and Method(s) for Fabricating the Same

Abstract

A one cylinder storage device and a method for fabricating a capacitor are disclosed, realizing simplified fabrication by overexposure with a mask having a plurality of holes, in which the method includes forming a contact hole in an insulating layer on a semiconductor substrate; forming a conductive layer on the insulating layer to fill the contact hole; forming a photoresist layer on the conductive layer; forming a photoresist layer pattern by overexposure and generating a side lobe phenomenon; forming a cylindrical lower electrode by patterning the conductive layer using the photoresist layer pattern as a mask; and forming a dielectric layer and an upper electrode covering the lower electrode.

1 . A method for fabricating a capacitor comprising:
 forming an insulating layer on a semiconductor substrate,   forming a contact hole in the insulating layer;   forming a conductive layer on the insulating layer to fill the contact hole;   forming a photoresist layer on the conductive layer;   forming a photoresist layer pattern in the photoresist layer by overexposure to generate a side lobe phenomenon;   forming a cylindrical lower electrode by patterning the conductive layer using the photoresist layer pattern as a mask; and   forming a dielectric layer and an upper electrode covering the lower electrode.   
   
   
       2 . The method of  claim 1 , wherein the step of forming the photoresist layer pattern includes:
 positioning a mask above the photoresist layer, the mask having a transmission part corresponding to the contact hole;   overexposing the photoresist layer using the mask; and   developing the overexposed photoresist layer.   
   
   
       3 . The method of  claim 2 , wherein the mask includes:
 a semi-transmission part through which light is transmitted at a transmittance of 6% to 15%; and   a transmission part corresponding to the portion for the contact hole, through which light is transmitted at about 100%.   
   
   
       4 . The method of  claim 2 , wherein an energy level of the overexposing is from about one and a half times to about two and a half times as high as an exposure energy level for patterning the contact hole. 
   
   
       5 . The method of  claim 1 , wherein the conductive layer comprises a conductive polysilicon layer. 
   
   
       6 . The method of  claim 1 , wherein the patterning process of the conductive layer comprises RIE (Reactive Ion Etching). 
   
   
       7 . A cylinder-type storage device, comprising:
 a plug in a dielectric layer on a semiconductor substrate, said plug comprising a conductive material; and   a lower electrode on the dielectric layer and in contact with the plug, the lower electrode comprising the conductive material, and wherein sidewalls of the lower electrode are substantially cylindrical in shape and have a flat upper surface.   
   
   
       8 . The cylinder-type storage device as recited in  claim 7 , wherein said plug and said lower electrode are unitary. 
   
   
       9 . The cylinder-type storage device as recited in  claim 7 , further comprising an etch stop layer on the dielectric layer, wherein an opening in the etch stop layer has a greater diameter than, and completely overlaps, an opening in the dielectric layer for the plug. 
   
   
       10 . The cylinder-type storage device as recited in  claim 7 , wherein a base of the lower electrode fills the opening in the etch stop layer. 
   
   
       11 . The cylinder-type storage device as recited in  claim 7 , wherein the etch stop layer has a thickness of from approximately 2,000 Å to approximately 3,000 Å. 
   
   
       12 . The cylinder-type storage device as recited in  claim 7 , wherein the conductive material comprises polysilicon. 
   
   
       13 . The cylinder-type storage device as recited in  claim 7 , wherein the sidewalls of the lower electrode have a substantially constant thickness. 
   
   
       14 . The cylinder-type storage device as recited in  claim 7 , further comprising a dielectric layer lining said sidewalls of the lower electrode, and an upper conductive electrode substantially filling said a cylinder defined by the substantially cylindrical sidewalls of the lower electrode. 
   
   
       15 . The method of  claim 1 , wherein the conductive layer is formed to a depth which is dependent on a height of the cylindrical lower electrode. 
   
   
       16 . The method of claim  23 , wherein the depth of the conductive layer may range between 2,000 Å and 10,000 Å, and the height of the cylindrical lower electrode is 2,000 Å to 10,000 Å. 
   
   
       17 . The method of  claim 2 , wherein the mask is a phase shift mask. 
   
   
       18 . The method of  claim 2 , wherein the mask has partially transmissive areas and transparent areas. 
   
   
       19 . The method of  claim 2 , further comprising overexposing the photoresist layer to create a virtual image on the semiconductor substrate from a peak. 
   
   
       20 . The method of  claim 1 , wherein the photoresist pattern in the photoresist layer has at least one substantially cylindrically-shaped structure.