Chemical vapor deposition of copper thin films for ultra large scale integration

초고집적회로를 위한 구리박막의 화학적 형성기술

  • Published : 1997.02.01

Abstract

We have investigated the formation techniques of copper thin films which would be useful for sub-quarter-micron integrated circuits. A chemical vapor deposition technology has been tried for the better side wall formation of the thin films, and a metal organic compound, named (hface)Cu(VTMS) (hexafluoroacetylacetonate vinyltrimethylsilane copper(I)) was used as the precursors. We have deposited the copper thin films on TiN and $SiO_2$substrates. The film resistivity and deposition selectivity have been measured as functions of substrate temperature and chamber pressure. Best electrical properties were obtained at $180^{\circ}C$ of substrate temperature and 0.6 Torr of chamber pressure. Under the optimum deposition conditions, polycrystalline copper structures were observed to be grown, and the deposition rate of 120 nm/min was measured. The electrical resistivity as low as 0.25$mu \Omega$.cm, and the surface roughness of 15.5 nm were also measured. These are the suitable electrical and material properties required in the sub-quarter-micron device fabrication. Also, in the substrate temperature range of 140-$250^{\circ}C$, high deposition selectivity was observed between TiN and $SiO_2$.

0.25$\mu\textrm{m}$이하의 최소선폭을 같는 초고집적회로에 사용할 수 있는 구리박막의 형성기술 을 조사하였다. 본 실험에서는 측면박막 형성에 적합한 화학적 증착을 시도하였으며 (hfac)Cu(VTMS)(hexafluoroacetylacetonate vinyltrimethylisilane copper(I))로 명명된 금속 유기 화합물을 원료로 사용하였다. 구리박막의 형성은 TiN와 $SiO_2$모재 위에 이루어 졌으며, 형성 중에 모재의 온도와 증착용기 내 압력의 함수로서 집적회로 공정상 주요 변수인 박막 의 비저항, 박막의 증착선택도를 측정하였다. 구리박막은 모재온도 $180^{\circ}C$와 증착용기의 압력 0.6Torr의 조건에서 가장 좋은 전기적 성질을 보여 주었다. 이 조건에서 형성된 구리박막은 다결정 구조를 나타내었으며 구리박막의 증착속도는 120nm/min, 비저항은 0.25$mu \Omega$.cm, 평균거칠기는 15.5nm로서 0.25$\mu\textrm{m}$이하 선폭의 집적회로에서 요구되는 전기적, 재료적 사양에 근접한 구리박막을 얻었다. 또한 140-$250^{\circ}C$의 모재 온도 범위에서 TiN모재와 $SiO_2$모재 사 이에 뚜렸한 증착선택성이 관측되었다.

Keywords

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