Effects of Plasma Pretreatment of the Cu Seed Layer on Cu Electroplating

Cu seed layer 표면의 플라즈마 전처리가 Cu 전기도금 공정에 미치는 효과에 관한 연구

  • O, Jun-Hwan (Dept.of Metallurgical Engineering, Inha University) ;
  • Lee, Seong-Uk (Dept.of Metallurgical Engineering, Inha University) ;
  • Lee, Jong-Mu (Dept.of Metallurgical Engineering, Inha University)
  • Published : 2001.09.01

Abstract

Electroplating is an attractive alternative deposition method for copper with the need for a conformal and conductive seed layer In addition, the Cu seed layer should be highly pure so as not to compromise the effective resistivity of the filled copper interconnect structure. This seed layer requires low electrical resistivity, low levels of impurities, smooth interface, good adhesion to the barrier metal and low thickness concurrent with coherence for ensuring void-free fill. The electrical conductivity of the surface plays an important role in formation of initial Cu nuclei, Cu nucleation is much easier on the substrate with higher electrical conductivities. It is also known that the nucleation processes of Cu are very sensitive to surface condition. In this study, copper seed layers deposited by magnetron sputtering onto a tantalum nitride barrier layer were used for electroplating copper in the forward pulsed mode. Prior to electroplating a copper film, the Cu seed layer was cleaned by plasma H$_2$ and $N_2$. In the plasma treatment exposure tome was varied from 1 to 20 min and plasma power from 20 to 140W. Effects of plasma pretreatment to Cu seed/Tantalum nitride (TaN)/borophosphosilicate glass (BPSG) samples on electroplating of copper (Cu) films were investigated.

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