Subject: CPU interconnects: beyond copper?

Complex ICs (CPUs and the like) are moving away from aluminum 
interconnects to copper, since copper conducts better and would generate 
less heat.

I understand that silver and gold are better conductors than copper.  
While gold is rather expensive, silver is reasonably priced per ounce, and 
I do not think a chip would use more than an ounce or two.  Given that 
they find a way of modifying the IC production process to work with it, is 
it possible that we will see a shift to silver-interconnect ICs?  Or is 
there a problem with it that I don't understand?

Also, are there any better conductors than copper/silver/gold that could 
possibly be used instead?

Re: CPU interconnects: beyond copper?