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반도체 구리 배선공정에서 표면 전처리가 이후 구리 전해/무전해 전착 박막에 미치는 영향

Effect of Surface Pretreatment on Film Properties Deposited by Electro-/Electroless Deposition in Cu Interconnection

  • 임태호 (숭실대학교 공과대학 화학공학과) ;
  • 김재정 (서울대학교 공과대학 화학생물공학부)
  • Lim, Taeho (Department of chemical engineering, Soongsil University) ;
  • Kim, Jae Jeong (Department of chemical and biological engineering, Seoul National University)
  • 투고 : 2016.10.14
  • 심사 : 2016.12.01
  • 발행 : 2017.02.28

초록

본 연구에서는 구리 배선 공정에서 구리 씨앗층 표면에 형성되는 구리 자연산화물을 제거하는 표면 전처리가 후속 구리 전착에 미치는 영향을 살펴보았다. 구리 배선 공정의 화학적 기계적 연마 공정에서 사용하는 citric acid 기반의 용액을 구리 표면 전처리 과정에 적용하여 표면에 존재하는 구리 자연 산화물을 제거하였고, 용액 조성 변화를 통해 산화물 제거의 선택성을 높여 구리 씨앗층의 손실을 최소화하였다. 또한 표면 전처리 후 구리 전해 전착과 무전해 전착을 시도하여 전착한 박막의 비저항, 표면 거칠기 등의 성질을 비교하고, 이를 통해 선택적으로 구리 산화물을 제거한 이후에 전착된 박막의 비저항과 표면 거칠기가 가장 낮게 나타남을 확인하였다.

This study investigated the effect of surface pretreatment, which removes native Cu oxides on Cu seed layer, on subsequent Cu electro-/electroless deposition in Cu interconnection. The native Cu oxides were removed by using citric acid-based solution frequently used in Cu chemical mechanical polishing process and the selective Cu oxide removal was successfully achieved by controlling the solution composition. The characterization of electro-/electrolessly deposited Cu films after the oxide removal was then performed in terms of film resistivity, surface roughness, etc. It was observed that the lowest film resistivity and surface roughness were obtained from the substrate whose native Cu oxides were selectively removed.

키워드

참고문헌

  1. "The National Technology Roadmap for Semiconductors",11, 1997 Edition, Semiconductor IndustryAssociation, Washington D.C., USA (1997).
  2. S.-K. Kim, M. C. Kang, H.-C. Koo, S. K. Cho, J. J. Kim, and J.-K. Yeo, 'Cu Metallization for Giga Level Devices Using Electrodeposition' J. Korean Electrochem. Soc., 10, 94 (2007). https://doi.org/10.5229/JKES.2007.10.2.094
  3. T. Lim, K. J. Park, M. J. Kim, H.-C. Koo, and J. J. Kim, 'Real-Time Observation of Cu Electroless Deposition Using OCP Measurement Assisted by QCM' J. Electrochem. Soc., 159, D724 (2012). https://doi.org/10.1149/2.056212jes
  4. T. Lim, K. J. Park, M. J. Kim, H.-C. Koo, K. H. Kim, S. Choe, and J. J. Kim, 'Real-Time Observation of Cu Electroless Deposition: Synergetic Suppression Effect of 2,2'-dipyridyl and 3-N,N'-Dimethylaminodithio-carbamoyl-1-propanesulfonic Acid' J. Electrochem. Soc., 161, D135 (2014). https://doi.org/10.1149/2.028404jes
  5. International Technology Roadmap for Semiconductors Reports 2.0 More Moore, 32, 2015 Edition, International Technology Roadmap for Semiconductors (2015).
  6. V. R. K. Gorantla, K. A. Assiongbon, S. V. Babu, and D. Roy, 'Citric Acid as a Complexing Agent in CMP of Cu - Investigation of Surface Reactions Using Impedance Spectroscopy' J. Electrochem. Soc., 152, G404 (2005). https://doi.org/10.1149/1.1890786
  7. A. F. Mayadas and M. Shatzkes, 'Electrical-Resistivity Model for Polycrystalline Films: the Case of Arbitrary Reflection at External Surfaces' Phys. Rev. B, 1, 1382 (1970). https://doi.org/10.1103/PhysRevB.1.1382
  8. F. M. Smits, 'Measurement of Sheet Resistivities with the Four-Point Probe' Bell Labs Techn. J., 37, 711 (1958). https://doi.org/10.1002/j.1538-7305.1958.tb03883.x
  9. J.-C. Chen and W.-T. Tsai, 'Effects of Hydrogen Peroxide and Alumina on Surface Characteristics of Copper Chemical-Mechanical Polishing in Citric Acid Slurries' Mater. Chem. Phys., 87, 387 (2004). https://doi.org/10.1016/j.matchemphys.2004.06.007
  10. M. J. Kim and J. J. Kim, 'Electrodeposition for the Fabrication of Copper Interconnection in Semiconductor Devices' Korean Chem. Eng. Res., 52, 26 (2014). https://doi.org/10.9713/kcer.2014.52.1.26