Thin film capacitor avoiding short circuit between electrodes

Abstract

There is provided a thin film capacitor including (a) a lower electrode, (b) an insulating layer formed burying the lower electrode therein and formed with a via-hole reaching the lower electrode, (c) a dielectric layer formed on an inner sidewall of the via-hole and covering an exposed surface of the lower electrode therewith, and (d) an upper electrode surrounded by the dielectric layer. In accordance with the thin film capacitor, the upper electrode is formed to be buried in the via-hole formed above the lower electrode. Hence, it is possible to prevent short-circuit between the upper and lower electrodes, and degradation of the dielectric layer during fabrication of a thin film capacitor, both of which enhances reliability of a capacitor. In addition, a multi-layered wiring structure could be readily fabricated on the thin film capacitor.

What is claimed is:  
     
         1 . A method of fabricating a thin film capacitor, comprising the steps of: 
 (a) forming a lower electrode either directly on a substrate or on a substrate with an insulating film sandwiched therebetween;    (b) forming an insulating layer over said lower electrode and said substrate;    (c) forming a via-hole through said insulating layer so that said via-hole reaches said lower electrode, to thereby expose a portion of a surface of said lower electrode;    (d) forming a dielectric layer so that said dielectric layer covers at least said exposed portion of a surface of said lower electrode; and    (e) forming an electrically conductive layer on said dielectric layer.    
     
     
         2 . A method of fabricating a thin film capacitor, comprising the steps of: 
 (a) forming a lower electrode either directly on a substrate or on a substrate with an insulating film sandwiched therebetween;    (b) forming an insulating layer over said lower electrode and said substrate;    (c) forming a via-hole through said insulating layer so that said via-hole reaches said lower electrode, to thereby expose a portion of a surface of said lower electrode;    (d) forming a dielectric layer so that said dielectric layer covers at least said exposed portion of a surface of said lower electrode;    (e) forming an electrically conductive layer on said dielectric layer so that said via-hole is not fully filled with said electrically conductive layer, said electrically conductive layer having two- or more-layered structure wherein layers have different resistances from one another;    (f) removing at least the outermost layer of said electrically conductive layer in a region other than said via-hole; and    (g) forming a metal plating film on said outermost layer in said via-hole.    
     
     
         3 . The method as set forth in  claim 2 , wherein said metal plating film is formed of a metal selected from the group consisting of copper, silver, gold, iron, nickel, tin, platinum, palladium, zinc, and alloys thereof.  
     
     
         4 . The method as set forth in  claim 2 , wherein said step (f) includes the steps of forming a mask filling said via-hole therewith, and etching said electrically conductive layer.  
     
     
         5 . The method as set forth in  claim 2 , wherein said electrically conductive film is formed in said step (e) so that it includes a three-layered structure including a first electrically conductive layer, a second electrically conductive layer formed on said first electrically conductive layer, and a third electrically conductive layer formed on said second electrically conductive layer, 
 said first and third electrically conductive layers being composed of a metal or metals selected from the group consisting of copper, silver, aluminum, metals belonging to VIIIa group, and metals belonging to Ib group, said second electrically conductive layer being composed of a metal or metals selected from the group consisting of titanium, chromium, metals belonging to IVa group, metals belonging to Va group, metals belonging to Via group, and alloys thereof.    
     
     
         6 . The method as set forth in  claim 2 , wherein said electrically conductive film is formed in said step (e) so that it includes a four-layered structure including a first electrically conductive layer, a second electrically conductive layer formed on said first electrically conductive layer, a third electrically conductive layer formed on said second electrically conductive layer, and a fourth electrically conductive layer formed on said third electrically conductive layer, 
 said first and third electrically conductive layers being composed of a metal or metals selected from the group consisting of titanium, chromium, metals belonging to IVa group, metals belonging to Va group, metals belonging to VIa group, and alloys thereof, said second and fourth electrically conductive layers being composed of a metal or metals selected from the group consisting of copper, silver, aluminum, metals belonging to VIIIa group, and metals belonging to Ib group.    
     
     
         7 . The method as set forth in  claim 2 , wherein said electrically conductive film is removed in a region other than said via-hole in said step (f) to thereby planarize a product resulting from said step (e).  
     
     
         8 . The method as set forth in  claim 2 , wherein said lower electrode is formed in said step (a) so that said via-hole has a width smaller than a width of said lower electrode.  
     
     
         9 . The method as set forth in  claim 2 , wherein said lower electrode is formed in said step (a) so as to be planar in shape.  
     
     
         10 . A method of fabricating a patterned structure, comprising the steps of: 
 (a) forming a four-layered structure on a substrate which is formed at least one via-hole, said four-layered structure including a first electrically conductive layer, a second electrically conductive layer formed on said first electrically conductive layer, a third electrically conductive layer formed on said second electrically conductive layer, and a fourth electrically conductive layer formed on said third electrically conductive layer;    (b) depositing a resist film on said fourth electrically conductive layer;    (c) removing said resist film in a region other than said via-hole;    (d) removing said fourth electrically conductive layer in a region other than said via-hole;    (e) removing said resist film residual in said via-hole;    (f) depositing a first metal film only in said via-hole by electroplating;    (g) removing an exposed portion of said third electrically conductive layer to thereby expose said second electrically conductive layer;    (h) forming a patterned resist film on said second electrically conductive layer;    (i) depositing a second metal film in said patterned resist film by electroplating;    (j) removing said patterned resist film; and    (k) removing said first and second electrically conductive layers in a region where said patterned resist film used to be.    
     
     
         11 . The method as set forth in  claim 10 , wherein said first and third electrically conductive layers are composed of a metal or metals selected from the group consisting of titanium, chromium, metals belonging to IVa group, metals belonging to Va group, metals belonging to VIa group, and alloys thereof, and said second and fourth electrically conductive layers are composed of a metal or metals selected from the group consisting of copper, silver, aluminum, metals belonging to VIIIa group, and metals belonging to Ib group.  
     
     
         12 . The method as set forth in  claim 10 , wherein said first metal film is composed of a metal selected from the group consisting of copper, silver, gold, iron, nickel, tin, platinum, palladium, zinc, and alloys thereof.  
     
     
         13 . A method of fabricating a patterned structure, comprising the steps of: 
 (a) forming a four-layered structure on a substrate which is formed at least one via-hole, said four-layered structure including a first electrically conductive layer, a second electrically conductive layer formed on said first electrically conductive layer, a third electrically conductive layer formed on said second electrically conductive layer, and a fourth electrically conductive layer formed on said third electrically conductive layer;    (b) depositing a resist film on said fourth electrically conductive layer;    (c) removing said resist film in a region other than said via-hole;    (d) removing said fourth electrically conductive layer in a region other than said via-hole;    (e) removing said resist film residual in said via-hole;    (f) depositing a first metal film only in said via-hole by electroplating;    (g) removing an exposed portion of said third electrically conductive layer to thereby expose said second electrically conductive layer;    (h) forming a patterned resist film on said second electrically conductive layer;    (i) removing said second electrically conductive layer in a region not covered with said patterned resist film;    (j) removing said patterned resist film;    (k) depositing a second metal film by electroplating in a region where said patterned resist film used to be; and    (k) removing said first electrically conductive layer in a region where said patterned resist film used not to be.    
     
     
         14 . The method as set forth in  claim 13 , wherein said first and third electrically conductive layers are composed of a metal or metals selected from the group consisting of titanium, chromium, metals belonging to IVa group, metals belonging to Va group, metals belonging to VIa group, and alloys thereof, and said second and fourth electrically conductive layers are composed of a metal or metals selected from the group consisting of copper, silver, aluminum, metals belonging to VIIIa group, and metals belonging to Ib group.  
     
     
         15 . The method as set forth in  claim 13 , wherein said first metal film is composed of a metal selected from the group consisting of copper, silver, gold, iron, nickel, tin, platinum, palladium, zinc, and alloys thereof.  
     
     
         16 . A method of fabricating a patterned structure, comprising the steps of: 
 (a) forming first and second electrically conductive layers in this order on a substrate;    (b) forming a patterned resist film on said second electrically conductive layer;    (c) etching said second electrically conductive layer with said patterned resist film being used as a mask;    (d) removing said patterned resist film;    (e) depositing a first metal film only on said second electrically conductive layer by electroplating; and    (f) removing said first electrically conductive layer in a region not covered with said first metal film.    
     
     
         17 . The method as set forth in  claim 16 , wherein said first electrically conductive layer is composed of a metal or metals selected from titanium, chromium, the group consisting of metals belonging to IVa group, metals belonging to Va group, metals belonging to VIa group, and alloys thereof, and said second electrically conductive layer is composed of a metal or metals selected from the group consisting of copper, silver, aluminum, metals belonging to VIIIa group, and metals belonging to Ib group.  
     
     
         18 . The method as set forth in  claim 16 , wherein said first metal film is composed of a metal selected from the group consisting of copper, silver, gold, iron, nickel, tin, platinum, palladium, zinc, and alloys thereof.  
     
     
         19 . A method of fabricating a patterned structure, comprising the steps of: 
 (a) forming a four-layered structure on a substrate, said four-layered structure including a first electrically conductive layer, a second electrically conductive layer formed on said first electrically conductive layer, a third electrically conductive layer formed on said second electrically conductive layer, and a fourth electrically conductive layer formed on said third electrically conductive layer;    (b) forming a patterned resist film on said fourth electrically conductive layer;    (c) etching said fourth electrically conductive layer with said patterned resist film being used as a mask;    (d) removing said patterned resist film;    (e) depositing a first metal film only on said fourth electrically conductive layer by electroplating; and    (f) removing said third, second and first electrically conductive layers in a region not covered with said first metal film.    
     
     
         20 . The method as set forth in  claim 19 , wherein said first and third electrically conductive layers are composed of a metal or metals selected from titanium, chromium, the group consisting of metals belonging to IVa group, metals belonging to Va group, metals belonging to Via group, and alloys thereof, and said second and fourth electrically conductive layers are composed of a metal or metals selected from the group consisting of copper, silver, aluminum, metals belonging to VIIIa group, and metals belonging to Ib group.  
     
     
         21 . The method as set forth in  claim 19 , wherein said first metal film is composed of a metal selected from the group consisting of copper, silver, gold, iron, nickel, tin, platinum, palladium, zinc, and alloys thereof.  
     
     
         22 . A method of fabricating a patterned structure, comprising the steps of: 
 (a) forming a patterned insulating layer on a substrate, said patterned insulating layer defining at least one via-hole;    (b) forming first and second electrically conductive layers in this order on said substrate;    (c) depositing a resist film over said second electrically conductive layer;    (d) removing said resist film in a region other than said via-hole;    (e) etching said second electrically conductive layer to thereby remove said second electrically conductive layer in a region other than said via-hole;    (f) removing said resist film in said via-hole;    (g) depositing a first metal film only on said second electrically conductive layer by electroplating; and    (h) removing said first electrically conductive layer in a region not covered with said first metal film.    
     
     
         23 . The method as set forth in  claim 22 , wherein said first electrically conductive layer is composed of a metal or metals selected from titanium, chromium, the group consisting of metals belonging to IVa group, metals belonging to Va group, metals belonging to VIa group, and alloys thereof, and said second electrically conductive layer is composed of a metal or metals selected from the group consisting of copper, silver, aluminum, metals belonging to VIIIa group, and metals belonging to Ib group.  
     
     
         24 . The method as set forth in  claim 22 , wherein said first metal film is composed of a metal selected from the group consisting of copper, silver, gold, iron, nickel, tin, platinum, palladium, zinc, and alloys thereof.  
     
     
         25 . A method of fabricating a patterned structure, comprising the steps of: 
 (a) forming a patterned insulating layer on a substrate, said patterned insulating layer defining at least one via-hole;    (b) forming first and second electrically conductive layers in this order on said substrate;    (c) depositing a resist film over said second electrically conductive layer;    (d) removing said resist film in a region other than said via-hole;    (e) etching said second electrically conductive layer to thereby remove said second electrically conductive layer in a region other than said via-hole;    (f) removing said resist film in said via-hole;    (g) depositing a first metal film only on said second electrically conductive layer by electroplating;    (h) removing said first electrically conductive layer in a region not covered with said first metal film;    (i) forming a second insulating layer on a product resulting from said step (h), said second insulating layer being patterned to define at least one second via-hole reaching said first metal film;    (j) forming a third insulating layer on said second insulating layer, said third insulating layer being patterned to define at least one third via-hole having a width greater than a width of said second via-hole; and    (k) repeating said steps (b) to (h).    
     
     
         26 . The method as set forth in  claim 25 , wherein said steps (i) to (k) are repeated by the desired number of times.  
     
     
         27 . A method of fabricating a patterned structure, comprising the steps of: 
 (a) forming a patterned insulating layer on a substrate, said patterned insulating layer defining at least one via-hole;    (b) forming a four-layered structure on said substrate, said four-layered structure including a first electrically conductive layer, a second electrically conductive layer formed on said first electrically conductive layer, a third electrically conductive layer formed on said second electrically conductive layer, and a fourth electrically conductive layer formed on said third electrically conductive layer;    (c) depositing a resist film over said fourth electrically conductive layer;    (d) removing said resist film in a region other than said via-hole;    (e) etching said fourth electrically conductive layer to thereby remove said fourth electrically conductive layer in a region other than said via-hole;    (f) removing said resist film in said via-hole;    (g) depositing a first metal film only on said fourth electrically conductive layer by electroplating; and    (h) removing said third, second and first electrically conductive layers in a region not covered with said first metal film.    
     
     
         28 . The method as set forth in  claim 27 , wherein said first and third electrically conductive layers are composed of a metal or metals selected from titanium, chromium, the group consisting of metals belonging to IVa group, metals belonging to Va group, metals belonging to VIa group, and alloys thereof, and said second and fourth electrically conductive layers are composed of a metal or metals selected from the group consisting of copper, silver, aluminum, metals belonging to VIIIa group, and metals belonging to Ib group.  
     
     
         29 . The method as set forth in  claim 27 , wherein said first metal film is composed of a metal selected from the group consisting of copper, silver, gold, iron, nickel, tin, platinum, palladium, zinc, and alloys thereof.  
     
     
         30 . A method of fabricating a patterned structure, comprising the steps of: 
 (a) forming a patterned insulating layer on a substrate, said patterned insulating layer defining at least one via-hole;    (b) forming a four-layered structure on said substrate, said four-layered structure including a first electrically conductive layer, a second electrically conductive layer formed on said first electrically conductive layer, a third electrically conductive layer formed on said second electrically conductive layer, and a fourth electrically conductive layer formed on said third electrically conductive layer;    (c) depositing a resist film over said fourth electrically conductive layer;    (d) removing said resist film in a region other than said via-hole;    (e) etching said fourth electrically conductive layer to thereby remove said fourth electrically conductive layer in a region other than said via-hole;    (f) removing said resist film in said via-hole;    (g) depositing a first metal film only on said fourth electrically conductive layer by electroplating;    (h) removing said third, second and first electrically conductive layers in a region not covered with said first metal film;    (i) forming a second insulating layer on a product resulting from said step (h), said second insulating layer being patterned to define at least one second via-hole reaching said first metal film;    (j) forming a third insulating layer on said second insulating layer, said third insulating layer being patterned to define at least one third via-hole having a width greater than a width of said second via-hole; and    (k) repeating said steps (b) to (h).    
     
     
         31 . The method as set forth in  claim 30 , wherein said steps (i) to (k) are repeated by the desired number of times.  
     
     
         32 . A method of fabricating a patterned structure, comprising the steps of: 
 (a) forming a patterned insulating layer on a substrate, said patterned insulating layer defining at least one via-hole;    (b) forming first and second electrically conductive layers in this order on said substrate, said second electrically conductive layer being composed of a catalyser metal which acts as a catalyser to metals with which electroless plating is carried out;    (c) depositing a resist film over said second electrically conductive layer;    (d) removing said resist film in a region other than said via-hole;    (e) etching said second and first electrically conductive layers in a region other than said via-hole;    (f) removing said resist film in said via-hole; and    (g) depositing first metal only on said second electrically conductive layer by electroless plating.    
     
     
         33 . The method as set forth in  claim 32 , wherein said first electrically conductive layer is composed of a metal or metals selected from titanium, chromium, the group consisting of metals belonging to IVa group, metals belonging to Va group, metals belonging to VIa group, and alloys thereof.  
     
     
         34 . A method of fabricating a patterned structure, comprising the steps of: 
 (a) forming a patterned insulating layer on a substrate, said patterned insulating layer defining at least one via-hole;    (b) forming first and second electrically conductive layers in this order on said substrate, said second electrically conductive layer being composed of a catalyser metal which acts as a catalyser to metals with which electroless plating is carried out;    (c) depositing a resist film over said second electrically conductive layer;    (d) removing said resist film in a region other than said via-hole;    (e) etching said second and first electrically conductive layers in a region other than said via-hole;    (f) removing said resist film in said via-hole;    (g) depositing first metal only on said second electrically conductive layer by electroless plating;    (h) forming a second insulating layer on a product resulting from said step (g), said second insulating layer being patterned to define at least one second via-hole reaching said second electrically conductive layer;    (i) forming a third insulating layer on said second insulating layer, said third insulating layer being patterned to define at least one third via-hole having a width greater than a width of said second via-hole; and    (j) repeating said steps (b) to (h).    
     
     
         35 . The method as set forth in  claim 34 , wherein said steps (h) to (j) may be repeated by the desired number of times.