Metal line stacking structure in semiconductor device and formation method thereof

Abstract

The method for forming a metal line stacking structure according to a preferred embodiment of the present invention comprises: sequentially forming a first barrier metal and a first metal layer on a lower dielectric layer that is disposed over a semiconductor substrate, and performing a plasma treatment; forming a second barrier metal on the plasma-treated first metal layer; selectively etching the second barrier metal, the first metal layer, and the first barrier metal to form a metal line layer including the second barrier metal, the first metal layer, and the first barrier metal, which respectively have a predetermined width; and sintering the metal line layer to raise a reaction between the first metal layer and the second barrier metal, thereby generating a metal compound layer.

1 . A metal line stacking structure in a semiconductor device, comprising:
 a metal line layer on a lower dielectric layer being disposed over the semiconductor substrate, the metal line layer having a predetermined width and including a first barrier metal, a first metal layer, and a second barrier metal that s are sequentially stacked;   a metal compound layer formed in interface between the first metal layer and the second barrier metal;   an inter-level dielectric layer formed over all the lower dielectric layer and the metal line layer;   a contact hole formed in the inter-level dielectric layer, a bottom of which is positioned within the metal compound; and   a metal plug being filled in the contact hole.   
   
   
       2 . The metal line stacking structure of  claim 1 , wherein the second barrier metal includes a titanium (Ti) layer and a titanium nitride (TiN) layer, wherein the TiN layer is formed on the Ti layer, and wherein a thickness of the Ti layer is between 100 and 300 angstroms, and a thickness of the TiN layer is between 200 and 600 angstroms. 
   
   
       3 . The metal line stacking structure of  claim 2 , wherein the first metal layer is formed of a material selected from the group consisting of aluminum, an aluminum-copper alloy, an aluminum-copper-silicon alloy, and an aluminum-silicon alloy, and wherein a thickness of the first metal layer is between 3000 and 8000 angstroms. 
   
   
       4 . The metal line stacking structure of  claim 3 , wherein the metal compound layer comprises TiAl 3  that is generated by a reaction between aluminum of the first metal layer and titanium (Ti) of the Ti layer. 
   
   
       5 . The metal line stacking structure of  claim 1 , further comprising a third barrier metal formed on an inner wall of the contact hole.