First Demonstration of 16nm Pitch Subtractive Ru Interconnects for Advanced Technology Nodes

The world's first 16 nm pitch subtractive Ru interconnects have been demonstrated; both structural and electrical results are demonstrated utilizing a Spacer Assisted Litho-Etch Litho-Etch (SALELE) process. Critical elements for process control to enable this process have also been identified. Moreover, the electrical resistivity for 16 nm pitch resistors was measured by the Temperature Coefficient of Resistivity (TCR) method, confirming that a resistivity of < 20 μΩ-cm can be achieved for 16 nm pitch subtractive Ru lines with AR 2.5 and above, which strongly supports the potential advantage of subtractive Ru interconnects over conventional damascene Cu interconnects for achieving low line resistance at ultra scaled dimensions.