Cu metallization using a permanent magnet electron cyclotron resonance microwave plasma/sputtering hybrid system

Abstract

A permanent magnet electron cyclotron resonance microwave plasma source has been coupled to a copper sputter target to produce ionized copper fluxes for submicron integrated circuit metallization. A custom launcher assembly allows the use of microwave powers up to 5 kW in a metal deposition environment to produce plasma densities ≳1012 cm−3, well above the cutoff density at 2.45 GHz of ∼1×1011 cm−3. Six hundred nm, 1.1:1 aspect ratio features have been filled with copper, and 250 nm, 6:1 aspect ratio features have been successfully lined. Copper ionization fractions for the conditions used for lining and filling, determined by a combination of Langmuir probe measurements and optical emission spectroscopy, are between 10% and 35%.