Partially-overlapped interconnect structure and method of making

Abstract

The present invention is concerned with an interconnect structure for providing electrical communication between an interconnect and a contact in a semiconductor device which includes a contact formed of aluminum or aluminum-copper, an aluminum-copper alloy film which is capable of substantially preventing the contact from being etched by an etchant and which covers substantially the contact, and an interconnect line formed of aluminum or aluminum-copper which at least partially covers the aluminum-copper film sufficient to provide electrical communication between the interconnect line and the contact. The present invention also provides a method for fabricating such interconnect structure.

1 . An interconnect structure for providing electrical communication between an interconnect and a contact in a semiconductor device comprising: 
 a contact of a first metallic material;    an alloy film covers substantially said contact, and    an interconnect line of a second metallic material at least partially covers said alloy film.    
     
     
         2 . An interconnect structure according to  claim 1 , wherein said first and said second metallic materials are selected from the group consisting of aluminum, aluminum alloys, copper, copper alloys, gold, gold alloys, silver and silver alloys.  
     
     
         3 . An interconnect structure according to  claim 1 , wherein said first and said second metallic materials are the same.  
     
     
         4 . An interconnect structure according to  claim 1 , wherein said first and said second metallic materials are aluminum and said alloy film is aluminum-copper.  
     
     
         5 . An interconnect structure according to  claim 1 , wherein said contact is a stud providing electrical communication between two interconnect lines.  
     
     
         6 . An interconnect structure according to  claim 1 , wherein said interconnect line and said contact are formed in an insulating material.  
     
     
         7 . An interconnect structure according to  claim 1 , wherein said alloy film is formed by first depositing a copper layer on an aluminum contact and then annealing to form an alloy.  
     
     
         8 . An interconnect structure according to  claim 1 , wherein said alloy film is capable of substantially preventing the contact from being etched by an etchant.  
     
     
         9 . An interconnect structure according to  claim 1 , wherein said interconnect line at least partially covers the alloy film sufficient to provide electrical communication between said interconnect line and said contact.  
     
     
         10 . A semiconductor structure comprising. 
 a contact formed of aluminum or aluminum-copper,    an aluminum-copper film capable of substantially preventing the contact from being etched by an etchant covers substantially said contact, and    an interconnect line formed of aluminum or aluminum-copper at least partially covers said aluminum-copper film sufficient to provide electrical communication between said interconnect line and said contact.    
     
     
         11 . A semiconductor structure according to  claim 10 , wherein said contact and said interconnect line are formed of aluminum.  
     
     
         12 . A semiconductor structure according to  claim 10 , wherein said aluminum-copper film is an etch-stop film sufficient to prevent said contact from being etched by an etchant during an etching process for said interconnect line.  
     
     
         13 . A method of fabricating an interconnect line on a contact in a semiconductor device comprising the steps of: 
 forming a contact of a first metallic material,    forming an alloy film to substantially cover said contact, said alloy film is capable of substantially preventing said contact from being etched by an etchant in a process for forming said interconnect line, and    forming an interconnect line of a second metallic material to at least partially cover said alloy film sufficient to provide electrical communication between said contact and said interconnect line.    
     
     
         14 . A method according to  claim 13 , wherein said first and said second metallic materials are selected from the group consisting of aluminum, aluminum alloys, copper, copper alloys, gold, gold alloys, silver and silver alloys.  
     
     
         15 . A method according to  claim 13 , wherein said first and said second metallic materials are aluminum and said alloy film is aluminum-copper.  
     
     
         16 . A method according to  claim 13 , wherein said contact is a stud connecting electrically between two interconnect lines.  
     
     
         17 . A method according to  claim 13 , wherein said interconnect line and said contact are formed in an insulating material.  
     
     
         18 . A method according to  claim 17 , wherein said insulating material is selected from the group consisting of silicon oxide, silicon nitride silicon oxynitride and low dielectric constant polymers.  
     
     
         19 . A method according to  claim 13 , wherein said forming step for said alloy film further comprising the steps of first depositing a layer of copper on an aluminum stud and then annealing to form an aluminum-copper layer overlying said stud.  
     
     
         20 . A method according to  claim 13 , wherein said forming step for said alloy film is a self-aligned forming method.