Low Resistive Ru Thin Film on Dielectrics without Adhesive Liner for Sub-2nm Interconnects

A low-pressure deposited, low-resistivity Ru thin film enables interconnects without adhesive liners for sub-2nm nodes and beyond. The newly developed low-pressure Ru deposition offers (1) a larger grain size of 14 nm, (2) smaller surface roughness of Ra = 0.16 nm, and the highest film density of 12.1 g/cm³, resulting in a record-low resistivity of 22.45 μΩ∙cm at a thickness of 20 nm in the as-deposited state, without any additional thermal annealing. The 10 nm Ru thin film exhibits sufficiently high adhesive strength on SiO<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> without the need for adhesive liners. The effective resistance, including liner resistance, is reduced by 15.9% compared to that with a Ta adhesive liner. The Ru thin film without the liner is a strong candidate for future advanced technology nodes.