Effect of process parameters on the angular distribution of sputtered Cu flux in long-throw sputtering system

Abstract

In this work, the angular distribution of the sputtered Cu flux in a long throw sputtering (LTS) system is extracted from the comparison of experimentally-measured profiles of deposited films with simulated profiles of films in overhang contact structure. And effects of the sputtering process parameters such as Ar pressure during sputtering, RF power on substrates, and DC power on Cu target are investigated for a DC magnetron sputtering system with LTS. The bottom step coverage in contact is enhanced with decreasing operating pressure and is increased with increasing substrate RF power up to 200 W. However, the bottom step-coverage was reduced with substrate RF power above 400 W, possibly due to the re-sputtering effect of the deposited Cu films. DC power on Cu target does not affect the angular distribution of Cu atoms while the overall deposition rate is increased. Based on the estimated angular distribution of sputtered Cu flux, the profile of Cu film is deposition on a deep via of aspect ratio 10 and compared to the simulation of the film profile that shows a good agreement.