Semiconductor device with ferro-electric capacitor

Abstract

A semiconductor device has a ferro-electric capacitor with small leak current and less process deterioration even upon miniaturization. The semiconductor device includes: a semiconductor element formed in a semiconductor substrate; lamination of an interlayer insulating film and a lower insulating shielding film having a hydrogen/moisture shielding function, the lamination being formed covering the semiconductor element; a conductive adhesion enhancing film formed above the lower insulating shielding film; and a ferro-electric capacitor including a lower electrode formed above the conductive adhesion enhancing film, a ferro-electric film formed on the lower electrode and being disposed within the lower electrode as viewed in plan, and an upper electrode formed on the ferro-electric film and being disposed within the ferro-electric film as viewed in plan, wherein the conductive adhesion enhancing film has a function of improving adhesion of the lower electrode and reducing leak current of the ferro-electric capacitor.

1 .- 11 . (canceled) 
     
     
         12 . A method for manufacturing a semiconductor device comprising steps of:
 (a) depositing an insulating oxygen barrier layer and an interlayer insulating film on a semiconductor substrate formed with a transistor;   (b) forming an insulating hydrogen diffusion preventive film above said interlayer insulating film;   (c) forming a conductive adhesion enhancing film containing Ti above said insulating hydrogen diffusion preventive film;   (d) forming a ferro-electric capacitor including a lamination of a lower electrode, a ferro-electric film and an upper electrode, with an upper layer not protruding outside a lower layer, above said conductive adhesion enhancing film; and   (e) performing annealing in an oxygen-containing atmosphere after said step (d).   
     
     
         13 . The method for manufacturing a semiconductor device according to  claim 12 , wherein said step (b) forms, by physical deposition or chemical deposition, a film made of at least one material selected from a group consisting of aluminum oxide, aluminum nitride, TiAlN, tantalum oxide, titanium oxide and zirconium oxide. 
     
     
         14 . The method for manufacturing a semiconductor device according to  claim 13 , wherein said step (b) forms an aluminum oxide film having a thickness of 1 to 100 nm. 
     
     
         15 . The method for manufacturing a semiconductor device according to  claim 12 , wherein said step (c) forms, by physical deposition or chemical deposition, a film made of at least one material selected from a group consisting of Ti, TiN, TiAlN and TiAlON. 
     
     
         16 . The method for manufacturing a semiconductor device according to  claim 15 , wherein said step (c) form a Ti film by sputtering. 
     
     
         17 . The method for manufacturing a semiconductor device according to  claim 16 , wherein said step (c) performs sputtering at a substrate temperature of 10 to 200° C. 
     
     
         18 . The method for manufacturing a semiconductor device according to  claim 12 , further comprising steps of:
 (f) forming conductive plugs through said insulating hydrogen diffusion preventive film, said interlayer insulating film and said insulating oxygen barrier film and reaching said transistors, between said steps (b) and (c); and   (g) forming a conductive oxygen barrier layer on said conductive adhesion enhancing film, between said steps (c) and (d).   
     
     
         19 . The method for manufacturing a semiconductor device according to  claim 18 , wherein said step (f) comprises steps of:
 (f-1) forming contact holes by etching through said insulating hydrogen diffusion preventive film, said interlayer insulating film and said insulating oxygen barrier layer;   (f-2) depositing plug material burying said contact holes; and   (f-3) removing said plug material on said insulating hydrogen diffusion preventive film by polishing, by using said insulating hydrogen diffusion preventive film as a stopper.   
     
     
         20 . The method for manufacturing a semiconductor device according to  claim 19 , wherein said step (f-3) is low pressure chemical mechanical polishing or electrolytic mechanical polishing.