Effect of air-contaminated TiN on the deposition characteristics of Cu film by MOCVD

공기 중에 노출된 MOCVD TiN 기판이 MOCVD Cu 증착에 미치는 효과

The deposition characteristics of Cu film by MOCVD using (hfac)Cu(1,5-COD)(1,1,1,5,5,5-hexafluro-2,4-pentadionato Cu(I) 1,5-cryclooctadiene) as a precursor have been investigated in terms of substrate conditions. Two different substrates such as air-exposed TiN and non-contaminated TiN were used for the MOCVD of Cu. MOCVD of Cu on the air-exposed TiN affected the nucleation rate of Cu as well as its growth, resulting in the Cu films having poor interconnection between particles with relatively small grains. On the other hand, in-situ MOCVD of Cu led to the Cu films having a significantly improved interconnection between particles with larger grains, indicating the resistivity as low as $2.0{\mu}{\Omega}-cm$ for the films having more than 1900$\AA$ thickness. Moreover, better adhesion of Cu films to the TiN by using in-situ MOCVD has been obtained. Finally, initial coalescence mechanism of Cu was suggested in this paper in terms of different substrate conditions by observing the surface morphology of the Cu films deposited by MOCVD.

(hfac) Cu(1,5-COD)(1,1,1,5,5,5-hexafluro-2,4-pentadionato Cu(I) 1,5-cyclooctadine) 증착원을 이용하여 MOCVD(metal organic chemical vapor deposition)로 Cu 박막을 형성시키고, MOCVD에 의한 TiN 기판 변화가 Cu 증착에 미치는 영향을 조사하였다. 공기 중에 노출시킨 기판은 MOCVD 에 의한 Cu 핵생성 및 초기성장에 영향을 미쳐 입자크기가 작고, 입자간의 연결성이 떨어졌으며, in-situ MOCVD Cu의 경우는 입자크기가 크고, 입자간의 연결성이 우수하여 1900$\AA$ 이상의 두께에서는 $2.0{\mu}{\Omega}-cm$ 정도의 낮은 비저항을 유지하였다. 또한 접착력에서는 in-situ MOCVD TiN 의 경우가 보다 우수하였다. 이와 같은 결과를 토대로 MOCVD Cu 성장단계를 제시하였다.