analog IC Interconnect material composition

[layout_designer]

Hi
When a foundry says cu or al interconnect material, is it 100% cu or al or will there be an alloy of these metals? there is not much info about this composition in the pdk.

Any help in this please
thanks

 

[Hughes]

Usually it is a multi-layer structure.

 

[layout_designer]

Hi Hughes

when we connect a node of one transistor to some other component we use a metal and some vias to connect them. Apart from these are there any other layers?

what is the composition of these layers? are these layers made of single metal or alloys of one main metal like cu or al.

can u please elaborate.
thanks in advance