Effects of input power, gas flow rate and hydrogen concentration on Cu film deposition by a radio frequency driven non-thermal atmospheric pressure plasma jet

Abstract

A radio frequency driven non-thermal atmospheric plasma jet with a copper wire used as precursor is applied for Cu film deposition. The effects of input power, hydrogen concentration (CH2) and gas flow rate on the discharge parameters, and eventually on film deposition rate and its properties are investigated. The results show that, besides the plasma gas temperature (Tg), the discharge current flowing through the copper wire (Ifc) is also a key parameter for Cu film deposition. With increasing input power, both Tg and Ifc increase, which both facilitate the increase of film deposition rate, surface roughness and particle size on the film. Higher gas flow rate leads to lower Tg, and results in the decrease of the deposition rate, surface roughness and particle size. The influences of CH2 in plasma forming gas on Cu film deposition have dual characters, due to the increase in the Tg and decease in the Ifc with CH2 increase. When the CH2 is below1.6‰, increasing CH2 has promotion role on the film deposition rate increase and particle size enlargement on the film, and the results reverse as the CH2 is above 1.6‰.