Electrodeposition of Copper for ULSI Metallization
최창희 , 이효종 , 민석홍 , 김기범 , 이동녕 Chang Hee Choi , Hyo Jong Lee , Seok Hong Min , Ki Bum Kim , Dong Nyung Lee
Abstract
The microstructural evolution of Cu films deposited by electroplating was investigated with the variation of the deposition rate from 0.1 ㎛/min to 3 ㎛/min by using a copper sulfate solution. Electrodeposition of copper was conducted on 0.1 ㎛ or 0.5 ㎛ thick copper seed layer deposited by sputtering process. The growth characteristics were investigated by monitoring the surface microstructure, electrical resistivity and chemical composition. The feasibility of electroplating process for ultra-large-scale integration(ULSI) metallization scheme was demonstrated through preferred crystallographic growth direction, resistivity and step coverage. The uniform Cu film was successfully electroplated at deposition rates from 0.5 to 3 ㎛/min and its continuous growth on the copper seed layer was observed in every specimen. The resistivity of as-deposited copper film made at deposition rates from 0.5 to 3 ㎛/min was about 2.5μΩ-㎝ and subsequent annealing in a vacuum at 200℃ for 2 min reduced it to 2.3μΩ-㎝.