Trench interconnect structure and formation method

Abstract

Embodiments concern vertical interconnect structures having sub-micron widths for use in integrated circuits, and methods of their manufacture, which result in reduced interconnect resistance, I 2 R losses, and defects or variations due to cusping. Embodiments of the methods involve forming an opening in an insulating layer, where the opening forms a trench that exposes an underlying portion of a metal layer. Additional embodiments involve depositing multiple layers of conductive material within the opening and above the insulating layer, where one of the conductive layers includes aluminum and is deposited using a “cold aluminum” process, and a second one of the conductive layers also includes aluminum, but is deposited using a “hot aluminum” process. The interconnect structures are adapted for use in conjunction with memory cells and apparatus incorporating such memory cells, as well as other integrated circuits.

1 . A method of forming a interconnect structure within a semiconductor device, the method comprising:
 forming an opening in an insulator to access a horizontal conductor;   forming a barrier layer on the horizontal conductor;   forming a first conductor portion on the barrier layer, the first conductor portion being formed from a metal conductor material using a process below a reflow temperature of the metal conductor material; and   forming a second conductor portion on the first conductor portion, the second conductor portion being formed from the metal conductor material using process above the reflow temperature of the metal conductor.   
     
     
         2 . The method of  claim 1 , wherein forming a first conductor portion includes forming a first conductor portion from a metal conductor material that includes aluminum. 
     
     
         3 . The method of  claim 1 , wherein forming a first conductor portion includes forming a first conductor portion from a metal conductor material that includes copper. 
     
     
         4 . The method of  claim 1 , wherein forming a first conductor portion includes forming a first conductor portion from a metal conductor material that is substantially pure aluminum. 
     
     
         5 . The method of  claim 1 , wherein forming a first conductor portion includes forming a first conductor portion at a temperature below 400° C. 
     
     
         6 . The method of  claim 1 , wherein forming a first conductor portion includes forming a first conductor portion at a temperature in a range between approximately 250° C. and 350° C. 
     
     
         7 . The method of  claim 1 , wherein forming a first conductor portion includes forming a first conductor portion at a temperature in a range between approximately 0° C. and 250° C. 
     
     
         8 . The method of  claim 1 , further including forming a second horizontal conductor integrally formed with the second conductor portion. 
     
     
         9 . A method of forming a interconnect structure within a semiconductor device, the method comprising:
 forming a trench via having a trench shape with a width of about 0.35 microns or less in an insulator to access a horizontal conductor;   forming a barrier layer on the horizontal conductor;   forming a first conductor portion on the barrier layer, the first conductor portion being formed from a metal conductor material using a process below a reflow temperature of the metal conductor material; and   forming a second conductor portion on the first conductor portion, the second conductor portion being formed from the metal conductor material using process above the reflow temperature of the metal conductor.   
     
     
         10 . The method of  claim 9 , wherein forming the barrier layer includes forming a barrier layer with a thickness in a range of about 100-200 angstroms. 
     
     
         11 . The method of  claim 9 , wherein forming first conductor portion includes forming a first conductor portion with a thickness in a range of about 2500-3500 angstroms. 
     
     
         12 . The method of  claim 9 , wherein forming a first conductor portion includes forming a first conductor portion from a metal conductor material that includes aluminum and titanium. 
     
     
         13 . The method of  claim 9 , wherein forming a first conductor portion includes forming a first conductor portion from a metal conductor material that includes copper. 
     
     
         14 . The method of  claim 9 , wherein forming a first conductor portion includes forming a first conductor portion from a metal conductor material that is substantially pure aluminum. 
     
     
         15 . A method of forming a interconnect structure within a semiconductor device, the method comprising:
 forming an opening in an insulator to access a horizontal conductor, the opening having a length in a horizontal plane that is sufficiently greater than a width of the opening;   forming a barrier layer on the horizontal conductor;   forming a first conductor portion on the barrier layer, the first conductor portion being formed from a metal conductor material using a process below a reflow temperature of the metal conductor material; and   forming a second conductor portion on the first conductor portion, the second conductor portion being formed from the metal conductor material using process above the reflow temperature of the metal conductor.   
     
     
         16 . The method of  claim 15 , wherein forming the barrier layer includes forming a barrier layer with a thickness in a range of about 100-200 angstroms. 
     
     
         17 . The method of  claim 15 , wherein forming the barrier layer includes forming a barrier layer that covers the horizontal conductor and sidewalls of the opening. 
     
     
         18 . The method of  claim 16 , wherein forming first conductor portion includes forming a first conductor portion with a thickness in a range of about 2500-3500 angstroms. 
     
     
         19 . The method of  claim 18 , wherein forming the second conductor portion includes forming a second conductor portion with a thickness in a range of about 200-300 angstroms. 
     
     
         20 . The method of  claim 15 , wherein forming the first conductor portion and the second conductor portion includes forming the first conductor portion and the second conductor portion from an aluminum conductor material.